WorldWideScience

Sample records for radiation belt variations

  1. Variations of Synchrotron Radio Emissions from Jupiter's Inner Radiation Belt

    Science.gov (United States)

    Lou, Y.-Q.

    2017-09-01

    Variations of Synchrotron Radio Emissions from Jupiter's Inner Radiation Belt Yu-Qing Lou* Physics Department, Tsinghua Centre for Astrophysics (THCA), Tsinghua-National Astronomical Observatories of China (NAOC) joint Research Centre for Astrophysics, Tsinghua University, Beijing 100084, China We describe the basic phenommenology of quasi-periodic 40 minute (QP-40) polar burst activities of Jupiter and their close correlation with the solar wind speed variations at the Jovian magnetosphere. Physically, relativistic electrons of QP-40 bursts most likely come from the circumpolar regions of the inner radiation belt (IRB) which gives off intense synchroton radio emissions in a wide wavelength range. Such relativistic electron bursts also give rise to beamed low-frequency radio bursts along polar magnetic field lines with distinct polarizations from Jupiter's two polar regions. Jovian aurora activities are expected to be also affected by such QP-40 burst activities. We present evidence of short-term (typical timescales shorter than an hour) variabilities of the IRB at 6cm wavelength and describe recent joint radio telescope observation campaign to monitor Jupiter in coordination with JUNO spacecraft. Except for low-frequency polarization features, we anticipate JUNO to detect QP-40 activities from both polar regions during the arrival of high-speed solar wind with intermittency. References 1. Y.-Q. Lou, The Astrophysical Journal, 548, 460 (2001). 2. Y.-Q. Lou, and C. Zheng, Mon. Not. Roy. Astron. Soc. Letters, 344, L1 (2003). 3. Y.-Q. Lou, H. G. Song, Y.Y. Liu, and M. Yang, Mon. Not. Roy. Astron. Soc. Letters, 421, L62 (2012). 4. Y.-Q. Lou, Geophysical Research Letters, 23, 609 (1996). 5. Y.-Q. Lou, Journal of Geophysical Research, 99, 14747 (1994). 6. G. R. Gladstone, et al., Nature, 415, 1000 (2002).

  2. Modeling of electron time variations in the radiation belts

    International Nuclear Information System (INIS)

    Chan, K.W.; Teague, M.J.; Schofield, N.J.; Vette, J.I.

    1979-01-01

    A review of the temporal variation in the trapped electron population of the inner and outer radiation zones is presented. Techniques presently used for modeling these zones are discussed and their deficiencies identified. An intermediate region is indicated between the zones in which the present modeling techniques are inadequate due to the magnitude and frequency of magnetic storms. Future trends are examined, and it is suggested that modeling of individual magnetic storms may be required in certain L bands. An analysis of seven magnetic storms is presented, establishing the independence of the depletion time of the storm flux and the storm magnitude. Provisional correlation between the storm magnitude and the Dst index is demonstrated

  3. Earth's radiation belts

    International Nuclear Information System (INIS)

    Moslehi Fard, M.

    1984-01-01

    The theory of trapped particles in a magnetic field of approximated dipole is described completely in the first part. Second part contains experimental results. The mechanism of radiation belt source ''albedo neutrons'' and also types of dissipation mechanism about radiation belt is explained. The trapped protons and electrons by radiation belt is discussed and the life-time of trapped particles are presented. Finally the magnetic fields of Moon, Venus, Mars, and Saturn, measured by passengers Mariner 4,10 and pioneer 10,11 are indicated. The experimental and theoretical results for the explanation of trapped plasma around the earth which is looked like two internal and external belt have almost good correspondence

  4. Solar Rotational Periodicities and the Semiannual Variation in the Solar Wind, Radiation Belt, and Aurora

    Science.gov (United States)

    Emery, Barbara A.; Richardson, Ian G.; Evans, David S.; Rich, Frederick J.; Wilson, Gordon R.

    2011-01-01

    The behavior of a number of solar wind, radiation belt, auroral and geomagnetic parameters is examined during the recent extended solar minimum and previous solar cycles, covering the period from January 1972 to July 2010. This period includes most of the solar minimum between Cycles 23 and 24, which was more extended than recent solar minima, with historically low values of most of these parameters in 2009. Solar rotational periodicities from S to 27 days were found from daily averages over 81 days for the parameters. There were very strong 9-day periodicities in many variables in 2005 -2008, triggered by recurring corotating high-speed streams (HSS). All rotational amplitudes were relatively large in the descending and early minimum phases of the solar cycle, when HSS are the predominant solar wind structures. There were minima in the amplitudes of all solar rotational periodicities near the end of each solar minimum, as well as at the start of the reversal of the solar magnetic field polarity at solar maximum (approx.1980, approx.1990, and approx. 2001) when the occurrence frequency of HSS is relatively low. Semiannual equinoctial periodicities, which were relatively strong in the 1995-1997 solar minimum, were found to be primarily the result of the changing amplitudes of the 13.5- and 27-day periodicities, where 13.5-day amplitudes were better correlated with heliospheric daily observations and 27-day amplitudes correlated better with Earth-based daily observations. The equinoctial rotational amplitudes of the Earth-based parameters were probably enhanced by a combination of the Russell-McPherron effect and a reduction in the solar wind-magnetosphere coupling efficiency during solstices. The rotational amplitudes were cross-correlated with each other, where the 27 -day amplitudes showed some of the weakest cross-correlations. The rotational amplitudes of the > 2 MeV radiation belt electron number fluxes were progressively weaker from 27- to 5-day periods

  5. Radiation Belt Test Model

    Science.gov (United States)

    Freeman, John W.

    2000-10-01

    Rice University has developed a dynamic model of the Earth's radiation belts based on real-time data driven boundary conditions and full adiabaticity. The Radiation Belt Test Model (RBTM) successfully replicates the major features of storm-time behavior of energetic electrons: sudden commencement induced main phase dropout and recovery phase enhancement. It is the only known model to accomplish the latter. The RBTM shows the extent to which new energetic electrons introduced to the magnetosphere near the geostationary orbit drift inward due to relaxation of the magnetic field. It also shows the effects of substorm related rapid motion of magnetotail field lines for which the 3rd adiabatic invariant is violated. The radial extent of this violation is seen to be sharply delineated to a region outside of 5Re, although this distance is determined by the Hilmer-Voigt magnetic field model used by the RBTM. The RBTM appears to provide an excellent platform on which to build parameterized refinements to compensate for unknown acceleration processes inside 5Re where adiabaticity is seen to hold. Moreover, built within the framework of the MSFM, it offers the prospect of an operational forecast model for MeV electrons.

  6. Variations of the Electron Fluxes in the Terrestrial Radiation Belts Due To the Impact of Corotating Interaction Regions and Interplanetary Coronal Mass Ejections

    Science.gov (United States)

    Benacquista, R.; Boscher, D.; Rochel, S.; Maget, V.

    2018-02-01

    In this paper, we study the variations of the radiation belts electron fluxes induced by the interaction of two types of solar wind structures with the Earth magnetosphere: the corotating interaction regions and the interplanetary coronal mass ejections. We use a statistical method based on the comparison of the preevent and postevent fluxes. Applied to the National Oceanic and Atmospheric Administration-Polar Operational Environmental Satellites data, this gives us the opportunity to extend previous studies focused on relativistic electrons at geosynchronous orbit. We enlighten how corotating interaction regions and Interplanetary Coronal Mass Ejections can impact differently the electron belts depending on the energy and the L shell. In addition, we provide a new insight concerning these variations by considering their amplitude. Finally, we show strong relations between the intensity of the magnetic storms related to the events and the variation of the flux. These relations concern both the capacity of the events to increase the flux and the deepness of these increases.

  7. Problems with models of the radiation belts

    International Nuclear Information System (INIS)

    Daly, E.J.; Lemaire, J.; Heynderickx, D.; Rodgers, D.J.

    1996-01-01

    The current standard models of the radiation-belt environment have many shortcomings, not the least of which is their extreme age. Most of the data used for them were acquired in the 1960's and early 1970's. Problems with the present models, and the ways in which data from more recent missions are being or can be used to create new models with improved functionality, are described. The phenomenology of the radiation belts, the effects on space systems, and geomagnetic coordinates and modeling are discussed. Errors found in present models, their functional limitations, and problems with their implementation and use are detailed. New modeling must address problems at low altitudes with the south Atlantic anomaly, east-west asymmetries and solar cycle variations and at high altitudes with the highly dynamic electron environment. The important issues in space environment modeling from the point of view of usability and relationship with effects evaluation are presented. New sources of data are discussed. Future requirements in the data, models, and analysis tools areas are presented

  8. Jupiter's magnetosphere and radiation belts

    Science.gov (United States)

    Kennel, C. F.; Coroniti, F. V.

    1979-01-01

    Radioastronomy and Pioneer data reveal the Jovian magnetosphere as a rotating magnetized source of relativistic particles and radio emission, comparable to astrophysical cosmic ray and radio sources, such as pulsars. According to Pioneer data, the magnetic field in the outer magnetosphere is radially extended into a highly time variable disk-shaped configuration which differs fundamentally from the earth's magnetosphere. The outer disk region, and the energetic particles confined in it, are modulated by Jupiter's 10 hr rotation period. The entire outer magnetosphere appears to change drastically on time scales of a few days to a week. In addition to its known modulation of the Jovian decametric radio bursts, Io was found to absorb some radiation belt particles and to accelerate others, and most importantly, to be a source of neutral atoms, and by inference, a heavy ion plasma which may significantly affect the hydrodynamic flow in the magnetosphere. Another important Pioneer finding is that the Jovian outer magnetosphere generates, or permits to escape, fluxes of relativistic electrons of such intensities that Jupiter may be regarded as the dominant source of 1 to 30 MeV cosmic ray electrons in the heliosphere.

  9. Storm-time radiation belt electron dynamics: Repeatability in the outer radiation belt

    Science.gov (United States)

    Murphy, K. R.; Mann, I. R.; Rae, J.; Watt, C.; Boyd, A. J.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J. F.

    2017-12-01

    During intervals of enhanced solar wind driving the outer radiation belt becomes extremely dynamic leading to geomagnetic storms. During these storms the flux of energetic electrons can vary by over 4 orders of magnitude. Despite recent advances in understanding the nature of competing storm-time electron loss and acceleration processes the dynamic behavior of the outer radiation belt remains poorly understood; the outer radiation belt can exhibit either no change, an enhancement, or depletion in radiation belt electrons. Using a new analysis of the total radiation belt electron content, calculated from the Van Allen probes phase space density (PSD), we statistically analyze the time-dependent and global response of the outer radiation belt during storms. We demonstrate that by removing adiabatic effects there is a clear and repeatable sequence of events in storm-time radiation belt electron dynamics. Namely, the relativistic (μ=1000 MeV/G) and ultra-relativistic (μ=4000 MeV/G) electron populations can be separated into two phases; an initial phase dominated by loss followed by a second phase dominated by acceleration. At lower energies, the radiation belt seed population of electrons (μ=150 MeV/G) shows no evidence of loss but rather a net enhancement during storms. Further, we investigate the dependence of electron dynamics as a function of the second adiabatic invariant, K. These results demonstrate a global coherency in the dynamics of the source, relativistic and ultra-relativistic electron populations as function of the second adiabatic invariant K. This analysis demonstrates two key aspects of storm-time radiation belt electron dynamics. First, the radiation belt responds repeatably to solar wind driving during geomagnetic storms. Second, the response of the radiation belt is energy dependent, relativistic electrons behaving differently than lower energy seed electrons. These results have important implications in radiation belt research. In particular

  10. Variations of electron fluxes in the outer radiation belt near the boundary of a trapping region during substorms

    International Nuclear Information System (INIS)

    Ginzburg, E.A.; Malyshev, A.B.

    1979-01-01

    Variations of electron fluxes with the energy Esub(e) > 0.7 MeV have been investigated near the high-latitude boundary of electron trapping region in the night and day sections of the magnetosphere. It is found that during substorms the natural changes of the structure of electron fluxes take place. On the night side of the magnetosphere after the flux boundary drift to the equator at the preliminary phase, its sharp drift to the pole at the explosion phase takes place with further slow ( during 1-2 hours) shift to the initial position. The boundary position reconstruction period coincide by duration with the life time of negative bays at magnetograms of the night section stations. On the day side the boundary of electron fluxes recorded drifts to the pole in 30-60 min after the beginning of the substorm exposion phase. The results obtained are interpreted within the framework of the theory of adiabatic drift of trapped electrons and their pitch-angular diffusion under the effect of very low frequency waves

  11. Electron Radiation Belts of the Solar System

    Science.gov (United States)

    Mauk, Barry; Fox, Nicola

    To address the question of what factors dictate similarities and differences between radiation belts, we present comparisons between the electron radiation belt spectra of all five strongly magnetized planets within the solar system: Earth, Jupiter, Saturn, Uranus, and Neptune. We choose the highest intensity observed electron spectrum within each system (highest specifically near 1 MeV) and compare them against expectations based on the so-called Kennel-Petschek limit (KP; 1966) for each system. For evaluating the KP limit, we begin with the new relativis-tically correct formulation of Summers et al. (2009) but then add several refinements of our own. Specifically, we: 1) utilized a much more flexible analytic spectral shape that allows us to accurately fit observed radiation belt spectra; 2) adopt the point of view that the anisotropy parameter is not a free parameter but must take on a minimal value, as originally proposed by Kennel and Petschek (1966); and 3) examine the differential characteristics of the KP limit along the lines of what Schulz and Davidson (1988) performed for the non-relativistic formula-tion. We find that three factors limit the highest electron radiation belt intensities within solar system planetary magnetospheres: a) whistler mode interactions that limit spectral intensities to a differential Kennel-Petschek limit (3 planets); b) the absence of robust acceleration pro-cesses associated with injection dynamics (1 planet); and c) material interactions between the radiation particles and clouds of gas and dust (1 planet).

  12. Estimates Of Radiation Belt Remediation Requirements

    Science.gov (United States)

    Tuszewski, M.; Hoyt, R. P.; Minor, B. M.

    2004-12-01

    A low-Earth orbit nuclear detonation could produce an intense artificial radiation belt of relativistic electrons. Many satellites would be destroyed within a few weeks. We present here simple estimates of radiation belt remediation by several different techniques, including electron absorption by gas release, pitch angle scattering by steady electric and magnetic fields from tether arrays, and pitch angle scattering by wave-particle interactions from in-situ transmitters. For each technique, the mass, size, and power requirements are estimated for a one-week remediation (e-folding) timescale, assuming that a 10 kTon blast trapped 1024 fission product electrons (1 to 8 MeV) at L = 1.5 in a dipolar belt of width dL = 0.1.

  13. Bayesian inference of radiation belt loss timescales.

    Science.gov (United States)

    Camporeale, E.; Chandorkar, M.

    2017-12-01

    Electron fluxes in the Earth's radiation belts are routinely studied using the classical quasi-linear radial diffusion model. Although this simplified linear equation has proven to be an indispensable tool in understanding the dynamics of the radiation belt, it requires specification of quantities such as the diffusion coefficient and electron loss timescales that are never directly measured. Researchers have so far assumed a-priori parameterisations for radiation belt quantities and derived the best fit using satellite data. The state of the art in this domain lacks a coherent formulation of this problem in a probabilistic framework. We present some recent progress that we have made in performing Bayesian inference of radial diffusion parameters. We achieve this by making extensive use of the theory connecting Gaussian Processes and linear partial differential equations, and performing Markov Chain Monte Carlo sampling of radial diffusion parameters. These results are important for understanding the role and the propagation of uncertainties in radiation belt simulations and, eventually, for providing a probabilistic forecast of energetic electron fluxes in a Space Weather context.

  14. 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.

  15. 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.

  16. Variation Process of Radiation Belt Electron Fluxes due to Interaction With Chorus and EMIC Rising-tone Emissions Localized in Longitude

    Science.gov (United States)

    Kubota, Y.; Omura, Y.

    2017-12-01

    Using results of test particle simulations of a large number of electrons interacting with a pair of chorus emissions, we create Green's functions to model the electron distribution function after all of the possible interactions with the waves [Omura et al., 2015]. Assuming that the waves are generated in a localized range of longitudes in the dawn side, we repeat taking the convolution integral of the Green's function with the distribution function of the electrons injected into the generation region of the localized waves. From numerical and theoretical analyses, we find that electron acceleration process only takes place efficiently below 4 MeV. Because extremely relativistic electrons go through the wave generation region rapidly due to grad-B0 and curvature drift, they don't have enough interaction time to be accelerated. In setting up the electrons after all interaction with chorus emissions as initial electron distribution function, we also compute the loss process of radiation belt electron fluxes due to interaction with EMIC rising-tone emissions generated in a localized range of longitudes in the dusk side [Kubota and Omura,2017]. References: (1) Omura, Y., Y. Miyashita, M. Yoshikawa, D. Summers, M. Hikishima, Y. Ebihara, and Y. Kubota (2015), Formation process of relativistic electron flux through interaction with chorus emissions in the Earth's inner magnetosphere, J. Geophys. Res. Space Physics, 120, 9545-9562, doi:10.1002/2015JA021563. (2) Kubota, Y., and Y. Omura (2017), Rapid precipitation of radiation belt electrons induced by EMIC rising tone emissions localized in longitude inside and outside the plasmapause, J. Geophys. Res. Space Physics, 122, 293-309, doi:10.1002/2016JA023267.

  17. Radiation Belts of Antiparticles in Planetary Magnetospheres

    Science.gov (United States)

    Pugacheva, G. I.; Gusev, A. A.; Jayanthi, U. B.; Martin, I. M.; Spjeldvik, W. N.

    2007-05-01

    The Earth's radiation belts could be populated, besides with electrons and protons, also by antiparticles, such as positrons (Basilova et al., 1982) and antiprotons (pbar). Positrons are born in the decay of pions that are directly produced in nuclear reactions of trapped relativistic inner zone protons with the residual atmosphere at altitudes in the range of about 500 to 3000 km over the Earth's surface. Antiprotons are born by high energy (E > 6 GeV) cosmic rays in p+p - p+p+p+ pbar and in p+p - p+p+n+nbar reactions. The trapping and storage of these charged anti-particles in the magnetosphere result in radiation belts similar to the classical Van Allen belts of protons and electrons. We describe the mathematical techniques used for numerical simulation of the trapped positron and antiproton belt fluxes. The pion and antiproton yields were simulated on the basis of the Russian nuclear reaction computer code MSDM, a Multy Stage Dynamical Model, Monte Carlo code, (i.e., Dementyev and Sobolevsky, 1999). For estimates of positron flux there we have accounted for ionisation, bremsstrahlung, and synchrotron energy losses. The resulting numerical estimates show that the positron flux with energy >100 MeV trapped into the radiation belt at L=1.2 is of the order ~1000 m-2 s-1 sr-1, and that it is very sensitive to the shape of the trapped proton spectrum. This confined positron flux is found to be greater than that albedo, not trapped, mixed electron/positron flux of about 50 m-2 s-1 sr-1 produced by CR in the same region at the top of the geomagnetic field line at L=1.2. As we show in report, this albedo flux also consists mostly of positrons. The trapped antiproton fluxes produced by CR in the Earth's upper rarified atmosphere were calculated in the energy range from 10 MeV to several GeV. In the simulations we included a mathematic consideration of the radial diffusion process, both an inner and an outer antiproton source, losses of particles due to ionization process

  18. Space electronics: radiation belts set new challenges

    International Nuclear Information System (INIS)

    Leray, J.L.; Barillot, C.; Boudenot, J.C.

    1999-01-01

    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)

  19. Statistical studies of energetic electrons in the outer radiation belt

    Energy Technology Data Exchange (ETDEWEB)

    Johnstone, A.D.; Rodgers, D.J.; Jones, G.H. E-mail: g.h.jones@ic.ac.uk

    1999-10-01

    The medium electron A (MEA) instrument aboard the CRRES spacecraft provided data on terrestrial radiation belt electrons in the energy range from 153 to 1582 keV, during 1990-91. These data have previously been used to produce an empirical model of the radiation belts from L=1.1 to 8.9, ordered according to 17 energy bands, 18 pitch angle bins, and 5 Kp ranges. Empirical models such as this are very valuable, but are prone to statistical fluctuations and gaps in coverage. In this study, in order to smooth the data and make it more easy to interpolate within data gaps, the pitch angle distribution at each energy in the model was fitted with a Bessel function. This provided a way to characterize the pitch angle in terms of only two parameters for each energy. It was not possible to model fluxes reliably within the loss cone because of poor statistics. The fitted distributions give an indication of the way in which pitch angle diffusion varies in the outer radiation belts. The two parameters of the Bessel function were found to vary systematically with L value, energy and Kp. Through the fitting of a simple function to these systematic variations, the number of parameters required to describe the model could be reduced drastically.

  20. On a new component of radiation belts

    International Nuclear Information System (INIS)

    Grigorov, N.L.; Kurnosova, L.V.; Razorenov, L.A.; Remizov, A.S.; Fradkin, M.I.; Moskovskij Gosudarstvennyj Univ.

    1982-01-01

    The mechanism of electron radiation belt filling with high-energy particles is discussed. Experimental data on particle fluxes in the Earth magnetosphere are presented. The experiments are carried out using the Cherenkov scintillation telescope installed on the ''Lightning-1'' satellite. Values of secondary particle flux obtained during the measurement at a height of 500 km and 30-40 th. km. coincide within the limits of errors. It is noted that secondary particle flux, equal to the albedo electron flux, is registered on large heights. This reason indicates the fact of forbidden angle filling with electrons with energies above 10 MeV

  1. Coordinates for Representing Radiation Belt Particle Flux

    Science.gov (United States)

    Roederer, Juan G.; Lejosne, Solène

    2018-02-01

    Fifty years have passed since the parameter "L-star" was introduced in geomagnetically trapped particle dynamics. It is thus timely to review the use of adiabatic theory in present-day studies of the radiation belts, with the intention of helping to prevent common misinterpretations and the frequent confusion between concepts like "distance to the equatorial point of a field line," McIlwain's L-value, and the trapped particle's adiabatic L* parameter. And too often do we miss in the recent literature a proper discussion of the extent to which some observed time and space signatures of particle flux could simply be due to changes in magnetospheric field, especially insofar as off-equatorial particles are concerned. We present a brief review on the history of radiation belt parameterization, some "recipes" on how to compute adiabatic parameters, and we illustrate our points with a real event in which magnetospheric disturbance is shown to adiabatically affect the particle fluxes measured onboard the Van Allen Probes.

  2. The Foundations of Radiation Belt Research

    Science.gov (United States)

    Ludwig, G. H.

    2008-12-01

    phenomenon. It also provided the first hint that there were two distinct radiation belts, although that conclusion was not reached until later. Although that new information was quickly announced, the results of the high altitude nuclear detonations were kept secret until well into 1959. They clearly revealed the charged particle shells created by the Argos nuclear detonations. The next major step in mapping and understanding the high-intensity radiation involved the launch of deep space probes Pioneers III and IV in December 1958 and March 1959. Although both launches fell short in their primary objective, to reach the moon, they traveled far enough from the Earth to fully meet the needs of the scientific experiment. They very clearly showed the two-radiation belt structure, and mapped its extent. They also showed the probable effect of a magnetic storm on 25 February, thus indicating the direct influence of solar activity on the outer belt. By the end of 1959, the existence of the Van Allen Radiation Belts and their general structure were solidly established, early information about the composition of the radiation was appearing in print, and energetic work was under way to understand the physics of the processes involved.

  3. Modeling of Jupiter's electron an ion radiation belts

    International Nuclear Information System (INIS)

    Sicard, Angelica

    2004-01-01

    In the Fifties, James Van Allen showed the existence of regions of the terrestrial magnetosphere consisted of energetic particles, trapped by the magnetic field: the radiation belts. The radiation belts of the Earth were the subject of many modeling works and are studied since several years at the Departement Environnement Spatial (DESP) of ONERA. In 1998, the DESP decided to adapt the radiation belts model of the Earth, Salammbo, to radiation environment of Jupiter. A first thesis was thus carried out on the subject and a first radiation belts model of electrons of Jupiter was developed [Santos-Costa, 2001]. The aim of this second thesis is to develop a radiation belts model for protons and heavy ions. In order to validate the developed model, the comparisons between Salammbo results and observations are essential. However, the validation is difficult in the case of protons and heavy ions because in-situ measurements of the probes are very few and most of the time contaminated by very energetic electrons. To solve this problem, a very good model of electrons radiation belts is essential to confirm or cancel the contamination of protons and heavy ions measurements. Thus, in parallel to the development of the protons and heavy ions radiation belts model, the electrons models, already existing, has been improved. Then Salammbo results have been compared to the different observations available (in-situ measurements, radio-astronomical observations). The different comparisons show a very good agreement between Salammbo results and observations. (author) [fr

  4. Space Weather Effects in the Earth's Radiation Belts

    Science.gov (United States)

    Baker, D. N.; Erickson, P. J.; Fennell, J. F.; Foster, J. C.; Jaynes, A. N.; Verronen, P. T.

    2018-02-01

    The first major scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or belts, of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. Recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed many novel properties of the radiation belts, especially for electrons at highly relativistic and ultra-relativistic kinetic energies. In this review we summarize the space weather impacts of the radiation belts. We demonstrate that many remarkable features of energetic particle changes are driven by strong solar and solar wind forcings. Recent comprehensive data show broadly and in many ways how high energy particles are accelerated, transported, and lost in the magnetosphere due to interplanetary shock wave interactions, coronal mass ejection impacts, and high-speed solar wind streams. We also discuss how radiation belt particles are intimately tied to other parts of the geospace system through atmosphere, ionosphere, and plasmasphere coupling. The new data have in many ways rewritten the textbooks about the radiation belts as a key space weather threat to human technological systems.

  5. Statistics of the outer radiation belt

    International Nuclear Information System (INIS)

    Rodgers, D.J.; Johnstone, A.D.

    1996-01-01

    The highly variable electron flux levels in the outer radiation belt come about by competition between time-dependent source and loss mechanisms. In order to identify some of the different mechanisms involved, we examine the statistics of the variability of fluxes at geostationary orbit. Data from the SEM-2 analyzer on Meteosat-3 and from GOES-7 are used. Correlation analysis is used to find time-delays between changes in flux at different energies. We see that low energy flux is added to this region during sub-storms and that higher energy fluxes appear after 2 or 3 days. Whilst the timescale for this process is brief compared to a complete cycle of the open-quote Recirculation close-quote energization process, it is consistent with the timescale of its final step endash outward radial diffusion. By isolating periods when no new injection of plasma occurs, we make an assessment of flux loss rates in a quiet magnetosphere. copyright 1996 American Institute of Physics

  6. Formation and Decay of the Inner Electron Radiation Belt

    Science.gov (United States)

    2017-01-09

    a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 09-01-2017 2. REPORT TYPE...radiation belt: CRAND and trapped solar protons......17 APPENDIX C - Inward diffusion and loss of radiation belt protons...transfer orbit that can be damaged by the intense charged -particle environment. Protons are the prominent hazard, often causing single event upsets in

  7. Survey of current situation in radiation belt modeling

    Science.gov (United States)

    Fung, Shing F.

    2004-01-01

    The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.

  8. Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization

    Science.gov (United States)

    Daglis, I.; Balasis, G.; Bourdarie, S.; Horne, R.; Khotyaintsev, Y.; Mann, I.; Santolik, O.; Turner, D.; Anastasiadis, A.; Georgiou, M.; Giannakis, O.; Papadimitriou, C.; Ropokis, G.; Sandberg, I.; Angelopoulos, V.; Glauert, S.; Grison, B., Kersten T.; Kolmasova, I.; Lazaro, D.; Mella, M.; Ozeke, L.; Usanova, M.

    2013-09-01

    We present the concept, objectives and expected impact of the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization) project, which is being implemented by a consortium of seven institutions (five European, one Canadian and one US) with support from the European Community's Seventh Framework Programme. The MAARBLE project employs multi-spacecraft monitoring of the geospace environment, complemented by ground-based monitoring, in order to analyze and assess the physical mechanisms leading to radiation belt particle energization and loss. Particular attention is paid to the role of ULF/VLF waves. A database containing properties of the waves is being created and will be made available to the scientific community. Based on the wave database, a statistical model of the wave activity dependent on the level of geomagnetic activity, solar wind forcing, and magnetospheric region will be developed. Multi-spacecraft particle measurements will be incorporated into data assimilation tools, leading to new understanding of the causal relationships between ULF/VLF waves and radiation belt dynamics. Data assimilation techniques have been proven as a valuable tool in the field of radiation belts, able to guide 'the best' estimate of the state of a complex system. The MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project has received funding from the European Union’s Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520.

  9. Radiation belt seed population and its association with the relativistic electron dynamics: A statistical study: Radiation Belt Seed Population

    International Nuclear Information System (INIS)

    Tang, C. L.; Wang, Y. X.; Ni, B.; Zhang, J.-C.

    2017-01-01

    Using the Van Allen Probes data, we study the radiation belt seed population and it associated with the relativistic electron dynamics during 74 geomagnetic storm events. Based on the flux changes of 1 MeV electrons before and after the storm peak, these storm events are divided into two groups of “non-preconditioned” and “preconditioned”. The statistical study shows that the storm intensity is of significant importance for the distribution of the seed population (336 keV electrons) in the outer radiation belt. However, substorm intensity can also be important to the evolution of the seed population for some geomagnetic storm events. For non-preconditioned storm events, the correlation between the peak fluxes and their L-shell locations of the seed population and relativistic electrons (592 keV, 1.0 MeV, 1.8 MeV, and 2.1 MeV) is consistent with the energy-dependent dynamic processes in the outer radiation belt. For preconditioned storm events, the correlation between the features of the seed population and relativistic electrons is not fully consistent with the energy-dependent processes. It is suggested that the good correlation between the radiation belt seed population and ≤1.0 MeV electrons contributes to the prediction of the evolution of ≤1.0 MeV electrons in the Earth’s outer radiation belt during periods of geomagnetic storms.

  10. An Experimental Concept for Probing Nonlinear Physics in Radiation Belts

    Science.gov (United States)

    Crabtree, C. E.; Ganguli, G.; Tejero, E. M.; Amatucci, B.; Siefring, C. L.

    2017-12-01

    A sounding rocket experiment, Space Measurement of Rocket-Released Turbulence (SMART), can be used to probe the nonlinear response to a known stimulus injected into the radiation belt. Release of high-speed neutral barium atoms (8- 10 km/s) generated by a shaped charge explosion in the ionosphere can be used as the source of free energy to seed weak turbulence in the ionosphere. The Ba atoms are photo-ionized forming a ring velocity distribution of heavy Ba+ that is known to generate lower hybrid waves. Induced nonlinear scattering will convert the lower hybrid waves into EM whistler/magnetosonic waves. The escape of the whistlers from the ionospheric region into the radiation belts has been studied and their observable signatures quantified. The novelty of the SMART experiment is to make coordinated measurement of the cause and effect of the turbulence in space plasmas and from that to deduce the role of nonlinear scattering in the radiation belts. Sounding rocket will carry a Ba release module and an instrumented daughter section that includes vector wave magnetic and electric field sensors, Langmuir probes and energetic particle detectors. The goal of these measurements is to determine the whistler and lower hybrid wave amplitudes and spectrum in the ionospheric source region and look for precipitated particles. The Ba release may occur at 600-700 km near apogee. Ground based cameras and radio diagnostics can be used to characterize the Ba and Ba+ release. The Van Allen Probes can be used to detect the propagation of the scattering-generated whistler waves and their effects in the radiation belts. By detecting whistlers and measuring their energy density in the radiation belts the SMART mission will confirm the nonlinear generation of whistlers through scattering of lower hybrid along with other nonlinear responses of the radiation belts and their connection to weak turbulence.

  11. High-energy outer radiation belt dynamic modeling

    International Nuclear Information System (INIS)

    Chiu, Y.T.; Nightingale, R.W.; Rinaldi, M.A.

    1989-01-01

    Specification of the average high-energy radiation belt environment in terms of phenomenological montages of satellite measurements has been available for some time. However, for many reasons both scientific and applicational (including concerns for a better understanding of the high-energy radiatino background in space), it is desirable to model the dynamic response of the high-energy radiation belts to sources, to losses, and to geomagnetic activity. Indeed, in the outer electron belt, this is the only mode of modeling that can handle the large intensity fluctuations. Anticipating the dynamic modeling objective of the upcoming Combined Release and Radiation Effects Satellite (CRRES) program, we have undertaken to initiate the study of the various essential elements in constructing a dynamic radiation belt model based on interpretation of satellite data according to simultaneous radial and pitch-angle diffusion theory. In order to prepare for the dynamic radiation belt modeling based on a large data set spanning a relatively large segment of L-values, such as required for CRRES, it is important to study a number of test cases with data of similar characteristics but more restricted in space-time coverage. In this way, models of increasing comprehensiveness can be built up from the experience of elucidating the dynamics of more restrictive data sets. The principal objectives of this paper are to discuss issues concerning dynamic modeling in general and to summarize in particular the good results of an initial attempt at constructing the dynamics of the outer electron radiation belt based on a moderately active data period from Lockheed's SC-3 instrument flown on board the SCATHA (P78-2) spacecraft. Further, we shall discuss the issues brought out and lessons learned in this test case

  12. Oscillations of the Outer Boundary of the Outer Radiation Belt During Sawtooth Oscillations

    Directory of Open Access Journals (Sweden)

    Jae-Hun Kim

    2006-09-01

    Full Text Available We report three sawtooth oscillation events observed at geosynchronous orbit where we find quasi-periodic (every 2-3 hours sudden flux increases followed by slow flux decreases at the energy levels of ˜50-400 keV. For these three sawtooth events, we have examined variations of the outer boundary of the outer radiation belt. In order to determine L values of the outer boundary, we have used data of relativistic electron flux observed by the SAMPEX satellite. We find that the outer boundary of the outer radiation belt oscillates periodically being consistent with sawtooth oscillation phases. Specifically, the outer boundary of the outer radiation belt expands (namely, the boundary L value increases following the sawtooth particle flux enhancement of each tooth, and then contracts (namely, the boundary L value decreases while the sawtooth flux decreases gradually until the next flux enhancement. On the other hand, it is repeatedly seen that the asymmetry of the magnetic field intensity between dayside and nightside decreases (increases due to the dipolarization (the stretching on the nightside as the sawtooth flux increases (decreases. This implies that the periodic magnetic field variations during the sawtooth oscillations are likely responsible for the expansion-contraction oscillations of the outer boundary of the outer radiation belt.

  13. Radiation Belt Transport Driven by Solar Wind Dynamic Pressure Fluctuations

    Science.gov (United States)

    Kress, B. T.; Hudson, M. K.; Ukhorskiy, A. Y.; Mueller, H.

    2012-12-01

    The creation of the Earth's outer zone radiation belts is attributed to earthward transport and adiabatic acceleration of electrons by drift-resonant interactions with electromagnetic fluctuations in the magnetosphere. Three types of radial transport driven by solar wind dynamic pressure fluctuations that have been identified are: (1) radial diffusion [Falthammer, 1965], (2) significant changes in the phase space density radial profile due to a single or few ULF drift-resonant interactions [Ukhorskiy et al., 2006; Degeling et al., 2008], and (3) shock associated injections of radiation belt electrons occurring in less than a drift period [Li et al., 1993]. A progress report will be given on work to fully characterize different forms of radial transport and their effect on the Earth's radiation belts. The work is being carried out by computing test-particle trajectories in electric and magnetic fields from a simple analytic ULF field model and from global MHD simulations of the magnetosphere. Degeling, A. W., L. G. Ozeke, R. Rankin, I. R. Mann, and K. Kabin (2008), Drift resonant generation of peaked relativistic electron distributions by Pc 5 ULF waves, textit{J. Geophys. Res., 113}, A02208, doi:10.1029/2007JA012411. Fälthammar, C.-G. (1965), Effects of Time-Dependent Electric Fields on Geomagnetically Trapped Radiation, J. Geophys. Res., 70(11), 2503-2516, doi:10.1029/JZ070i011p02503. Li, X., I. Roth, M. Temerin, J. R. Wygant, M. K. Hudson, and J. B. Blake (1993), Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC, textit{Geophys. Res. Lett., 20}(22), 2423-2426, doi:10.1029/93GL02701. Ukhorskiy, A. Y., B. J. Anderson, K. Takahashi, and N. A. Tsyganenko (2006), Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons, textit{Geophys. Res. Lett., 33}(6), L06111, doi:10.1029/2005GL024380.

  14. A comparison of outer electron radiation belt dropouts during solar ...

    Indian Academy of Sciences (India)

    Utilizing multiple data sources from the year 1997–2007, this study identifies radiation belt electron dropouts which are ultimately triggered when solar wind stream interfaces (SI) arrived at ... Center for Space Research, School for Physical and Chemical Sciences, North–West University, Potchefstroom 2520, South Africa.

  15. Quantitative Simulation of QARBM Challenge Events During Radiation Belt Enhancements

    Science.gov (United States)

    Li, W.; Ma, Q.; Thorne, R. M.; Bortnik, J.; Chu, X.

    2017-12-01

    Various physical processes are known to affect energetic electron dynamics in the Earth's radiation belts, but their quantitative effects at different times and locations in space need further investigation. This presentation focuses on discussing the quantitative roles of various physical processes that affect Earth's radiation belt electron dynamics during radiation belt enhancement challenge events (storm-time vs. non-storm-time) selected by the GEM Quantitative Assessment of Radiation Belt Modeling (QARBM) focus group. We construct realistic global distributions of whistler-mode chorus waves, adopt various versions of radial diffusion models (statistical and event-specific), and use the global evolution of other potentially important plasma waves including plasmaspheric hiss, magnetosonic waves, and electromagnetic ion cyclotron waves from all available multi-satellite measurements. These state-of-the-art wave properties and distributions on a global scale are used to calculate diffusion coefficients, that are then adopted as inputs to simulate the dynamical electron evolution using a 3D diffusion simulation during the storm-time and the non-storm-time acceleration events respectively. We explore the similarities and differences in the dominant physical processes that cause radiation belt electron dynamics during the storm-time and non-storm-time acceleration events. The quantitative role of each physical process is determined by comparing against the Van Allen Probes electron observations at different energies, pitch angles, and L-MLT regions. This quantitative comparison further indicates instances when quasilinear theory is sufficient to explain the observed electron dynamics or when nonlinear interaction is required to reproduce the energetic electron evolution observed by the Van Allen Probes.

  16. 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.

  17. 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...

  18. Nonlinear Whistler Wave Physics in the Radiation Belts

    Science.gov (United States)

    Crabtree, Chris

    2016-10-01

    Wave particle interactions between electrons and whistler waves are a dominant mechanism for controlling the dynamics of energetic electrons in the radiation belts. They are responsible for loss, via pitch-angle scattering of electrons into the loss cone, and energization to millions of electron volts. It has previously been theorized that large amplitude waves on the whistler branch may scatter their wave-vector nonlinearly via nonlinear Landau damping leading to important consequences for the global distribution of whistler wave energy density and hence the energetic electrons. It can dramatically reduce the lifetime of energetic electrons in the radiation belts by increasing the pitch angle scattering rate. The fundamental building block of this theory has now been confirmed through laboratory experiments. Here we report on in situ observations of wave electro-magnetic fields from the EMFISIS instrument on board NASA's Van Allen Probes that show the signatures of nonlinear scattering of whistler waves in the inner radiation belts. In the outer radiation belts, whistler mode chorus is believed to be responsible for the energization of electrons from 10s of Kev to MeV energies. Chorus is characterized by bursty large amplitude whistler mode waves with frequencies that change as a function of time on timescales corresponding to their growth. Theories explaining the chirping have been developed for decades based on electron trapping dynamics in a coherent wave. New high time resolution wave data from the Van Allen probes and advanced spectral techniques are revealing that the wave dynamics is highly structured, with sub-elements consisting of multiple chirping waves with discrete frequency hops between sub-elements. Laboratory experiments with energetic electron beams are currently reproducing the complex frequency vs time dynamics of whistler waves and in addition revealing signatures of wave-wave and beat-wave nonlinear wave-particle interactions. These new data

  19. Nonlinear Scattering of VLF Waves in the Radiation Belts

    Science.gov (United States)

    Crabtree, Chris; Rudakov, Leonid; Ganguli, Guru; Mithaiwala, Manish

    2014-10-01

    Electromagnetic VLF waves, such as whistler mode waves, control the lifetime of trapped electrons in the radiation belts by pitch-angle scattering. Since the pitch-angle scattering rate is a strong function of the wave properties, a solid understanding of VLF wave sources and propagation in the magnetosphere is critical to accurately calculate electron lifetimes. Nonlinear scattering (Nonlinear Landau Damping) is a mechanism that can strongly alter VLF wave propagation [Ganguli et al. 2010], primarily by altering the direction of propagation, and has not been accounted for in previous models of radiation belt dynamics. 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]. Recent results show that the threshold for nonlinear 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 scattering can then dramatically 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]. By considering these effects, the lifetimes of electrons can be dramatically reduced. This work is supported by the Naval Research Laboratory base program.

  20. Low altitude observations of the energetic electrons in the outer radiation belt during isolated substorms

    International Nuclear Information System (INIS)

    Varga, L.; Venkatesan, D.; Johns Hopkins Univ., Laurel, MD; Meng, C.I.

    1985-01-01

    The low energy (1-20 keV) detector registering particles onboard the polar-orbiting low altitude (approx. 850 km) DMSP-F2 and -F3 satellites also records high energy electrons penetrating the detector walls. Thus the dynamics of this electron population at L=3.5 can be studied during isolated periods of magnetospheric substorms identified by the indices of auroral electrojet (AE), geomagnetic (Ksub(p)) and ring current (Dsub(st)). Temporal changes in the electron flux during the substorms are observed to be an additional contribution riding over the top of the pre-storm (or geomagnetically quiet-time) electron population; the duration of the interval of intensity variations is observed to be about the same as that of the enhancement of the AE index. This indicates the temporal response of the outer radiation belt to the substorm activity, since the observation was made in the ''horns'' of the outer radiation belt. The observed enhanced radiation at low altitude may associate with the instantaneous increase and/or dumping of the outer radiation belt energetic electrons during each isolated substorm activity. (author)

  1. Canadian radiation belt science in the ILWS era

    Science.gov (United States)

    Mann, I. R.

    The Outer Radiation Belt Injection, Transport, Acceleration, and Loss Satellite (ORBITALS) is a Canadian Space Agency small satellite mission proposed as a Canadian contribution to the satellite infrastructure for the International Living With a Star (ILWS) program. Planned to operate contemporaneously with the NASA Radiation Belt Storm Probes (RBSP), the ORBITALS will monitor the energetic electron and ion populations in the inner magnetosphere across a wide range of energies (keV to tens of MeV) as well as the dynamic electric and magnetic fields, waves, and cold plasma environment which govern the injection, transport, acceleration and loss of these energetic and space weather critical particle populations in the inner magnetosphere. Currently in Phase A Design Study, the ORBITALS will be launched into a low-inclination GTO-like orbit which every second orbit maximizes the long lasting apogee-pass conjunctions with both the ground-based instruments of the Canadian Geospace Monitoring (CGSM) array as well as with the GOES East and West and geosynchronous communications satellites in the North American sector. In a twelve-hour orbit, every second apogee will conjunct with instrumentation 180 degree in longitude away in the Asian sector. Specifically, the ORBITALS will make the measurements necessary to reach reveal fundamental new understanding of the relative importance of different physical processes (for example VLF verses ULF waves) which shape the energetic particle populations in the inner magnetosphere, as well as providing the raw radiation measurements at MEO altitudes necessary for the development of the next-generation of radiation belt specification models. On-board experiments will also monitor the dose, single event upset, and deep-dielectric charging responses of electronic components on-orbit. Supporting ground-based measurements of ULF and higher frequency wave fields from the Canadian CARISMA (www.carisma.ca) magnetometer array, as well as from

  2. Internal Charging Design Environments for the Earths Radiation Belts

    Science.gov (United States)

    Minow, Joseph I.; Edwards, David L.

    2009-01-01

    Relativistic electrons in the Earth's radiation belts are a widely recognized threat to spacecraft because they penetrate lightly shielded vehicle hulls and deep into insulating materials where they accumulate to sufficient levels to produce electrostatic discharges. Strategies for evaluating the magnitude of the relativistic electron flux environment and its potential for producing ESD events are varied. Simple "rule of thumb" estimates such as the widely used 10(exp 10) e-/sq cm fluence within 10 hour threshold for the onset of pulsing in dielectric materials provide a quick estimate of when to expect charging issues. More sophisticated strategies based on models of the trapped electron flux within the Earth s magnetic field provide time dependent estimates of electron flux along spacecraft orbits and orbit integrate electron flux. Finally, measurements of electron flux can be used to demonstrate mean and extreme relativistic electron environments. This presentation will evaluate strategies used to specify energetic electron flux and fluence environments along spacecraft trajectories in the Earth s radiation belts.

  3. Examining Relativistic Electron Loss in the Outer Radiation Belt

    Science.gov (United States)

    Green, J. C.; Onsager, T. G.; O'Brien, P.

    2003-12-01

    Since the discovery of earth's radiation belts researchers have sought to identify the mechanisms that dictate the seemingly erratic relativistic electron flux levels in the outer belt. Contrary to intuition, relativistic electron flux levels do not always increase during geomagnetic storms even though these storms signify enhanced energy input from the solar wind to the magnetosphere [Reeves et al., 2003; O'Brien et al., 2001]. The fickle response of the radiation belt electrons to geomagnetic activity suggests that flux levels are determined by the outcome of a continuous competition between acceleration and loss. Some progress has been made developing and testing acceleration mechanisms but little is known about how relativistic electrons are lost. We examine relativistic electron losses in the outer belt focusing our attention on flux decrease events of the type first described by Onsager et al. [2002]. The study showed a sudden decrease of geosynchronous >2MeV electron flux occurring simultaneously with local stretching of the magnetic field. The decrease was first observed near 15:00 MLT and progressed to all local times after a period of ˜10 hours. Expanding on the work of Onsager et al. [2002], we have identified ˜ 51 such flux decrease events in the GOES and LANL data and present the results of a superposed epoch analysis of solar wind data, geomagnetic activity indicators, and locally measured magnetic field and plasma data. The analysis shows that flux decreases occur after 1-2 days of quiet condition. They begin when either the solar wind dynamic pressure increases or Bz turns southward pushing hot dense plasma earthward to form a partial ring current and stretched magnetic field at dusk. Adiabatic electron motion in response to the stretched magnetic field may explain the initial flux reduction; however, often the flux does not recover with the magnetic field recovery, indicating that true loss from the magnetosphere is occurring. Using Polar and

  4. Detailed characteristics of radiation belt electrons revealed by CSSWE/REPTile measurements: Geomagnetic activity response and precipitation observation

    Science.gov (United States)

    Zhang, K.; Li, X.; Schiller, Q.; Gerhardt, D.; Zhao, H.; Millan, R.

    2017-08-01

    Earth's outer radiation belt electrons are highly dynamic. We study the detailed characteristics of relativistic electrons in the outer belt using measurements from the Colorado Student Space Weather Experiment (CSSWE) mission, a low Earth orbit (LEO) CubeSat, which traverses the radiation belt four times in one orbit ( 1.5 h) and has the advantage of measuring the dynamic activities of the electrons including their rapid precipitation. We focus on the measured electron response to geomagnetic activity for different energies to show that there are abundant sub-MeV electrons in the inner belt and slot region. These electrons are further enhanced during active times, while there is a lack of >1.63 MeV electrons in these regions. We also show that the variation of measured electron flux at LEO is strongly dependent on the local magnetic field strength, which is far from a dipole approximation. Moreover, a specific precipitation band, which happened on 19 January 2013, is investigated based on the conjunctive measurement of CSSWE, the Balloon Array for Radiation belt Relativistic Electron Losses, and one of the Polar Operational Environmental Satellites. In this precipitation band event, the net loss of the 0.58-1.63 MeV electrons (L = 3.5-6) is estimated to account for 6.8% of the total electron content.

  5. The quiet time structure of energetic (35--560 keV) radiation belt electrons

    International Nuclear Information System (INIS)

    Lyons, L.R.; Williams, D.J.

    1975-01-01

    Detailed Explorer 45 equatorial observations of the quiet time structure of radiation belt electrons (35--560 keV) for 1.7approximately-less-thanLapproximately-less-than5.2 are presented. Throughout the slot region and outer regions of the plasmasphere the observed pitch angle distributions are found to agree with those expected from resonant interactions with the plasmaspheric whistler mode wave band. Coulomb collisions become the dominant loss mechanism within the inner zone. The overall two-zone structure of the observed radial profiles is found to agree with the equilibrium structure expected to result from a balance between pitch angle scattering losses and radial diffusion from an average outer zone source. This agreement suggests that the dominant quiet time source and loss mechanisms have been identified and evaluated for energetic radiation belt electrons within the plasmasphere. In the outer regions of the plasmasphere (Lapprox.5) the equilibrium structure is observed to be modified by daily flux variations associated with changes in the level of magnetic activity that occur even during relatively quiet times. Within the inner region of the plasmasphere (Lapproximately-less-than3.5), electron fluxes are decoupled from these magnetic activity variations by the long time scales (>10 days) required for pitch angle and radial diffusion. Consequently, fluxes of these electrons are observed to remain nearly constant at equilibrium levels throughout the quiet periods examined

  6. Prediction Model of the Outer Radiation Belt Developed by Chungbuk National University

    Directory of Open Access Journals (Sweden)

    Dae-Kyu Shin

    2014-12-01

    Full Text Available The Earth’s outer radiation belt often suffers from drastic changes in the electron fluxes. Since the electrons can be a potential threat to satellites, efforts have long been made to model and predict electron flux variations. In this paper, we describe a prediction model for the outer belt electrons that we have recently developed at Chungbuk National University. The model is based on a one-dimensional radial diffusion equation with observationally determined specifications of a few major ingredients in the following way. First, the boundary condition of the outer edge of the outer belt is specified by empirical functions that we determine using the THEMIS satellite observations of energetic electrons near the boundary. Second, the plasmapause locations are specified by empirical functions that we determine using the electron density data of THEMIS. Third, the model incorporates the local acceleration effect by chorus waves into the one-dimensional radial diffusion equation. We determine this chorus acceleration effect by first obtaining an empirical formula of chorus intensity as a function of drift shell parameter L*, incorporating it as a source term in the one-dimensional diffusion equation, and lastly calibrating the term to best agree with observations of a certain interval. We present a comparison of the model run results with and without the chorus acceleration effect, demonstrating that the chorus effect has been incorporated into the model to a reasonable degree.

  7. The evolution of Saturn's radiation belts modulated by changes in radial diffusion

    Science.gov (United States)

    Kollmann, P.; Roussos, E.; Kotova, A.; Paranicas, C.; Krupp, N.

    2017-12-01

    Globally magnetized planets, such as the Earth1 and Saturn2, are surrounded by radiation belts of protons and electrons with kinetic energies well into the million electronvolt range. The Earth's proton belt is supplied locally from galactic cosmic rays interacting with the atmosphere3, as well as from slow inward radial transport4. Its intensity shows a relationship with the solar cycle4,5 and abrupt dropouts due to geomagnetic storms6,7. Saturn's proton belts are simpler than the Earth's because cosmic rays are the principal source of energetic protons8 with virtually no contribution from inward transport, and these belts can therefore act as a prototype to understand more complex radiation belts. However, the time dependence of Saturn's proton belts had not been observed over sufficiently long timescales to test the driving mechanisms unambiguously. Here we analyse the evolution of Saturn's proton belts over a solar cycle using in-situ measurements from the Cassini Saturn orbiter and a numerical model. We find that the intensity in Saturn's proton radiation belts usually rises over time, interrupted by periods that last over a year for which the intensity is gradually dropping. These observations are inconsistent with predictions based on a modulation in the cosmic-ray source, as could be expected4,9 based on the evolution of the Earth's proton belts. We demonstrate that Saturn's intensity dropouts result instead from losses due to abrupt changes in magnetospheric radial diffusion.

  8. First Results of Modeling Radiation Belt Electron Dynamics with the SAMI3 Plasmasphere Model

    Science.gov (United States)

    Komar, C. M.; Glocer, A.; Huba, J.; Fok, M. C. H.; Kang, S. B.; Buzulukova, N.

    2017-12-01

    The radiation belts were one of the first discoveries of the Space Age some sixty years ago and radiation belt models have been improving since the discovery of the radiation belts. The plasmasphere is one region that has been critically important to determining the dynamics of radiation belt populations. This region of space plays a critical role in describing the distribution of chorus and magnetospheric hiss waves throughout the inner magnetosphere. Both of these waves have been shown to interact with energetic electrons in the radiation belts and can result in the energization or loss of radiation belt electrons. However, radiation belt models have been historically limited in describing the distribution of cold plasmaspheric plasma and have relied on empirically determined plasmasphere models. Some plasmasphere models use an azimuthally symmetric distribution of the plasmasphere which can fail to capture important plasmaspheric dynamics such as the development of plasmaspheric drainage plumes. Previous work have coupled the kinetic bounce-averaged Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model used to model ring current and radiation belt populations with the Block-adaptive Tree Solar wind Roe-type Upwind Scheme (BATSRUS) global magnetohydrodynamic model to self-consistently obtain the magnetospheric magnetic field and ionospheric potential. The present work will utilize this previous coupling and will additionally couple the SAMI3 plasmasphere model to better represent the dynamics on the plasmasphere and its role in determining the distribution of waves throughout the inner magnetosphere. First results on the relevance of chorus, hiss, and ultralow frequency waves on radiation belt electron dynamics will be discussed in context of the June 1st, 2013 storm-time dropout event.

  9. Forecasting of Radiation Belts: Results From the PROGRESS Project.

    Science.gov (United States)

    Balikhin, M. A.; Arber, T. D.; Ganushkina, N. Y.; Walker, S. N.

    2017-12-01

    Forecasting of Radiation Belts: Results from the PROGRESS Project. The overall goal of the PROGRESS project, funded in frame of EU Horizon2020 programme, is to combine first principles based models with the systems science methodologies to achieve reliable forecasts of the geo-space particle radiation environment.The PROGRESS incorporates three themes : The propagation of the solar wind to L1, Forecast of geomagnetic indices, and forecast of fluxes of energetic electrons within the magnetosphere. One of the important aspects of the PROGRESS project is the development of statistical wave models for magnetospheric waves that affect the dynamics of energetic electrons such as lower band chorus, hiss and equatorial noise. The error reduction ratio (ERR) concept has been used to optimise the set of solar wind and geomagnetic parameters for organisation of statistical wave models for these emissions. The resulting sets of parameters and statistical wave models will be presented and discussed. However the ERR analysis also indicates that the combination of solar wind and geomagnetic parameters accounts for only part of the variance of the emissions under investigation (lower band chorus, hiss and equatorial noise). In addition, advances in the forecast of fluxes of energetic electrons, exploiting empirical models and the first principles IMPTAM model achieved by the PROGRESS project is presented.

  10. 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

  11. Automated Identification and Shape Analysis of Chorus Elements in the Van Allen Radiation Belts

    Science.gov (United States)

    Sen Gupta, Ananya; Kletzing, Craig; Howk, Robin; Kurth, William; Matheny, Morgan

    2017-12-01

    An important goal of the Van Allen Probes mission is to understand wave-particle interaction by chorus emissions in terrestrial Van Allen radiation belts. To test models, statistical characterization of chorus properties, such as amplitude variation and sweep rates, is an important scientific goal. The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrumentation suite provides measurements of wave electric and magnetic fields as well as DC magnetic fields for the Van Allen Probes mission. However, manual inspection across terabytes of EMFISIS data is not feasible and as such introduces human confirmation bias. We present signal processing techniques for automated identification, shape analysis, and sweep rate characterization of high-amplitude whistler-mode chorus elements in the Van Allen radiation belts. Specifically, we develop signal processing techniques based on the radon transform that disambiguate chorus elements with a dominant sweep rate against hiss-like chorus. We present representative results validating our techniques and also provide statistical characterization of detected chorus elements across a case study of a 6 s epoch.

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

    International Nuclear Information System (INIS)

    Grigoryan, O.R.; Panasyuk, M.I.; Petrov, A.N.; Kudela, K.

    2005-01-01

    In this work the features of low-energy proton flux increases in near-equatorial region (McIlvein parameter L th 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)

  13. Rapid flattening of butterfly pitch angle distributions of radiation belt electrons by whistler-mode chorus

    Science.gov (United States)

    Yang, Chang; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Blake, J. B.; Funsten, H. O.

    2016-08-01

    Van Allen radiation belt electrons exhibit complex dynamics during geomagnetically active periods. Investigation of electron pitch angle distributions (PADs) can provide important information on the dominant physical mechanisms controlling radiation belt behaviors. Here we report a storm time radiation belt event where energetic electron PADs changed from butterfly distributions to normal or flattop distributions within several hours. Van Allen Probes observations showed that the flattening of butterfly PADs was closely related to the occurrence of whistler-mode chorus waves. Two-dimensional quasi-linear STEERB simulations demonstrate that the observed chorus can resonantly accelerate the near-equatorially trapped electrons and rapidly flatten the corresponding electron butterfly PADs. These results provide a new insight on how chorus waves affect the dynamic evolution of radiation belt electrons.

  14. Rapid flattening of butterfly pitch angle distributions of radiation belt electrons by whistler-mode chorus

    International Nuclear Information System (INIS)

    Yang, Chang; Changsha University of Science and Technology, Changsha; Su, Zhenpeng; Xiao, Fuliang; Zheng, Huinan

    2016-01-01

    Van Allen radiation belt electrons exhibit complex dynamics during geomagnetically active periods. Investigation of electron pitch angle distributions (PADs) can provide important information on the dominant physical mechanisms controlling radiation belt behaviors. In this paper, we report a storm time radiation belt event where energetic electron PADs changed from butterfly distributions to normal or flattop distributions within several hours. Van Allen Probes observations showed that the flattening of butterfly PADs was closely related to the occurrence of whistler-mode chorus waves. Two-dimensional quasi-linear STEERB simulations demonstrate that the observed chorus can resonantly accelerate the near-equatorially trapped electrons and rapidly flatten the corresponding electron butterfly PADs. Finally, these results provide a new insight on how chorus waves affect the dynamic evolution of radiation belt electrons.

  15. Detailed Characteristics of Radiation Belt Electrons Revealed by CSSWE/REPTile Measurements

    Science.gov (United States)

    Zhang, K.; Li, X.; Schiller, Q.; Gerhardt, D. T.; Millan, R. M.

    2016-12-01

    The outer radiation belt electrons are highly dynamic. We study the detailed characteristics of the relativistic electrons in the outer belt using measurements from the Colorado Student Space Weather Experiment (CSSWE) mission, a low Earth orbit Cubesat, which transverses the radiation belt four times in one orbit ( 1.5 hr) and has the advantage of measuring the dynamic activities of the electrons including their rapid precipitations. Among the features of the relativistic electrons, we show the measured electron distribution as a function of geomagnetic activities and local magnetic field strength. Moreover, a specific precipitation band, which happened on 19 Jan 2013, is investigated based on the conjunctive measurement of CSSWE and the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL). In this precipitation band event, the net loss of the 0.58 1.63 MeV electrons (L=3.5 6) is estimated to account for 6.84% of the total electron content.

  16. RF communications subsystem for the Radiation Belt Storm Probes mission

    Science.gov (United States)

    Srinivasan, Dipak K.; Artis, David; Baker, Ben; Stilwell, Robert; Wallis, Robert

    2009-12-01

    The NASA Radiation Belt Storm Probes (RBSP) mission, currently in Phase B, is a two-spacecraft, Earth-orbiting mission, which will launch in 2012. The spacecraft's S-band radio frequency (RF) telecommunications subsystem has three primary functions: provide spacecraft command capability, provide spacecraft telemetry and science data return, and provide accurate Doppler data for navigation. The primary communications link to the ground is via the Johns Hopkins University Applied Physics Laboratory's (JHU/APL) 18 m dish, with secondary links to the NASA 13 m Ground Network and the Tracking and Data Relay Spacecraft System (TDRSS) in single-access mode. The on-board RF subsystem features the APL-built coherent transceiver and in-house builds of a solid-state power amplifier and conical bifilar helix broad-beam antennas. The coherent transceiver provides coherency digitally, and controls the downlink data rate and encoding within its field-programmable gate array (FPGA). The transceiver also provides a critical command decoder (CCD) function, which is used to protect against box-level upsets in the C&DH subsystem. Because RBSP is a spin-stabilized mission, the antennas must be symmetric about the spin axis. Two broad-beam antennas point along both ends of the spin axis, providing communication coverage from boresight to 70°. An RF splitter excites both antennas; therefore, the mission is designed such that no communications are required close to 90° from the spin axis due to the interferometer effect from the two antennas. To maximize the total downlink volume from the spacecraft, the CCSDS File Delivery Protocol (CFDP) has been baselined for the RBSP mission. During real-time ground contacts with the APL ground station, downlinked files are checked for errors. Handshaking between flight and ground CFDP software results in requests to retransmit only the file fragments lost due to dropouts. This allows minimization of RF link margins, thereby maximizing data rate and

  17. 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

  18. Conceptual design of a Moving Belt Radiator (MBR) shuttle-attached experiment

    Science.gov (United States)

    Aguilar, Jerry L.

    1990-01-01

    The conceptual design of a shuttle-attached Moving Belt Radiator (MBR) experiment is presented. The MBR is an advanced radiator concept in which a rotating belt is used to radiate thermal energy to space. The experiment is developed with the primary focus being the verification of the dynamic characteristics of a rotating belt with a secondary objective of proving the thermal and sealing aspects in a reduced gravity, vacuum environment. The mechanical design, selection of the belt material and working fluid, a preliminary test plan, and program plan are presented. The strategy used for selecting the basic sizes and materials of the components are discussed. Shuttle and crew member requirements are presented with some options for increasing or decreasing the demands on the STS. An STS carrier and the criteria used in the selection process are presented. The proposed carrier for the Moving Belt Radiator experiment is the Hitchhiker-M. Safety issues are also listed with possible results. This experiment is designed so that a belt can be deployed, run at steady state conditions, run with dynamic perturbations imposed, verify the operation of the interface heat exchanger and seals, and finally be retracted into a stowed position for transport back to earth.

  19. Explaining the Diverse Response of the Ultra-relativistic Van Allen Radiation Belt to Solar Wind Forcing

    Science.gov (United States)

    Mann, I. R.; Ozeke, L.; Murphy, K. R.; Claudepierre, S. G.; Rae, J.; Milling, D. K.; Kale, A.; Baker, D. N.

    2017-12-01

    The NASA Van Allen Probes have opened a new window on the dynamics of ultra-relativistic electrons in the Van Allen radiation belts. Under different solar wind forcing the outer belt is seen to respond in a variety of apparently diverse and sometimes remarkable ways. For example, sometimes a third radiation belt is carved out (e.g., September 2012), or the belts can remain depleted for 10 days or more (September 2014). More usually there is a sequential response of a strong and sometimes rapid depletion followed by a re-energization, the latter increasing outer belt electron flux by orders of magnitude on hour timescales during some of the strongest storms of this solar cycle (e.g., March 2013, March 2015). Such dynamics also appear to be often bounded at low-L by an apparently impenetrable barrier at L 2.8 through which ultra-relativistic electrons do not penetrate. Many studies in the Van Allen Probes era have sought explanations for these apparently diverse features, often incorporating the effects from multiple plasma waves. In contrast, we show how this apparently diverse behaviour can instead be explained by one dominant process: ULF wave radial transport. Once ULF wave transport rates are accurately specified by observations, and coupled to the dynamical variation of the outer boundary condition at the edge of the outer belt, the observed diverse responses can all be explained. However, in order to get good agreement with observations, the modeling reveals the importance of still currently unexplained very fast loss in the main phase which results in an almost total extinction of the belts and decouples pre- and post-storm ultra-relativistic electron flux on hour timescales. Similarly, varying plasmasheet source populations are seen to be of critical importance such that near-tail dynamics play a crucial role in Van Allen belt dynamics. Nonetheless, simple models incorporating accurate transport rates derived directly from ULF wave measurements are shown to

  20. A three-dimensional phase space dynamical model of the Earth's radiation belt

    International Nuclear Information System (INIS)

    Boscher, D. M.; Beutier, T.; Bourdarie, S.

    1996-01-01

    A three dimensional phase space model of the Earth's radiation belt is presented. We have taken into account the magnetic and electric radial diffusions, the pitch angle diffusions due to Coulomb interactions and interactions with the plasmaspheric hiss, and the Coulomb drag. First, a steady state of the belt is presented. Two main maxima are obtained, corresponding to the inner and outer parts of the belt. Then, we have modelled a simple injection at the external boundary. The particle transport seems like what was measured aboard satellites. A high energy particle loss is found, by comparing the model results and the measurements. It remains to be explained

  1. Lognormal Kalman filter for assimilating phase space density data in the radiation belts

    Science.gov (United States)

    Kondrashov, D.; Ghil, M.; Shprits, Y.

    2011-11-01

    Data assimilation combines a physical model with sparse observations and has become an increasingly important tool for scientists and engineers in the design, operation, and use of satellites and other high-technology systems in the near-Earth space environment. Of particular importance is predicting fluxes of high-energy particles in the Van Allen radiation belts, since these fluxes can damage spaceborne platforms and instruments during strong geomagnetic storms. In transiting from a research setting to operational prediction of these fluxes, improved data assimilation is of the essence. The present study is motivated by the fact that phase space densities (PSDs) of high-energy electrons in the outer radiation belt—both simulated and observed—are subject to spatiotemporal variations that span several orders of magnitude. Standard data assimilation methods that are based on least squares minimization of normally distributed errors may not be adequate for handling the range of these variations. We propose herein a modification of Kalman filtering that uses a log-transformed, one-dimensional radial diffusion model for the PSDs and includes parameterized losses. The proposed methodology is first verified on model-simulated, synthetic data and then applied to actual satellite measurements. When the model errors are sufficiently smaller then observational errors, our methodology can significantly improve analysis and prediction skill for the PSDs compared to those of the standard Kalman filter formulation. This improvement is documented by monitoring the variance of the innovation sequence.

  2. Precipitated Fluxes of Radiation Belt Electrons via Injection of Whistler-Mode Waves

    Science.gov (United States)

    Kulkarni, P.; Inan, U. S.; Bell, T. F.

    2005-12-01

    Inan et al. (U.S. Inan et al., Controlled precipitation of radiation belt electrons, Journal of Geophysical Research-Space Physics, 108 (A5), 1186, doi: 10.1029/2002JA009580, 2003.) suggested that the lifetime of energetic (a few MeV) electrons in the inner radiation belts may be moderated by in situ injection of whistler mode waves at frequencies of a few kHz. We use the Stanford 2D VLF raytracing program (along with an accurate estimation of the path-integrated Landau damping based on data from the HYDRA instrument on the POLAR spacecraft) to determine the distribution of wave energy throughout the inner radiation belts as a function of injection point, wave frequency and injection wave normal angle. To determine the total wave power injected and its initial distribution in k-space (i.e., wave-normal angle), we apply the formulation of Wang and Bell ( T.N.C. Wang and T.F. Bell, Radiation resistance of a short dipole immersed in a cold magnetoionic medium, Radio Science, 4 (2), 167-177, February 1969) for an electric dipole antenna placed at a variety of locations throughout the inner radiation belts. For many wave frequencies and wave normal angles the results establish that most of the radiated power is concentrated in waves whose wave normals are located near the resonance cone. The combined use of the radiation pattern and ray-tracing including Landau damping allows us to make quantitative estimates of the magnetospheric distribution of wave power density for different source injection points. We use these results to estimate the number of individual space-based transmitters needed to significantly impact the lifetimes of energetic electrons in the inner radiation belts. Using the wave power distribution, we finally determine the energetic electron pitch angle scattering and the precipitated flux signatures that would be detected.

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

    International Nuclear Information System (INIS)

    Albeverio, S.; Blanchard, P.; Combe, P.; Rodriguez, R.; Sirugue, M.; Sirugue-Collin, M.

    1984-11-01

    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

  4. The Global Statistical Response of the Outer Radiation Belt During Geomagnetic Storms

    Science.gov (United States)

    Murphy, K. R.; Watt, C. E. J.; Mann, I. R.; Jonathan Rae, I.; Sibeck, D. G.; Boyd, A. J.; Forsyth, C. F.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J.

    2018-05-01

    Using the total radiation belt electron content calculated from Van Allen Probe phase space density, the time-dependent and global response of the outer radiation belt during storms is statistically studied. Using phase space density reduces the impacts of adiabatic changes in the main phase, allowing a separation of adiabatic and nonadiabatic effects and revealing a clear modality and repeatable sequence of events in storm time radiation belt electron dynamics. This sequence exhibits an important first adiabatic invariant (μ)-dependent behavior in the seed (150 MeV/G), relativistic (1,000 MeV/G), and ultrarelativistic (4,000 MeV/G) populations. The outer radiation belt statistically shows an initial phase dominated by loss followed by a second phase of rapid acceleration, while the seed population shows little loss and immediate enhancement. The time sequence of the transition to the acceleration is also strongly μ dependent and occurs at low μ first, appearing to be repeatable from storm to storm.

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

    International Nuclear Information System (INIS)

    Kurose, Y.; Hayashi, Y.; Horiguchi, I.; Fukaishi, K.; Kanechika, O.; Ishida, H.; Sakurai, Y.; Sakai, T.; Yamauchi, Y.; Kohno, Y.

    1996-01-01

    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

  6. Detection of the strange bodies on the conveyor belt using gamma radiation technique

    International Nuclear Information System (INIS)

    Barna, A.; Ochiana, G.; Oncescu, M.

    1990-01-01

    The aim of this paper is to present a method for the computation of the activity of a gamma radiation source used in a radiometric assembly designed to detect the strange bodies (iron, stone or wood-made granules) within the textile material on the conveyor belt. The mathematical modelling method based on the Monte Carlo procedure has been used, with different values of the errors of types I and II; the investigation method is the transmission of gamma radiations. (Author)

  7. Effects of Drift-Shell Splitting by Chorus Waves on Radiation Belt Electrons

    Science.gov (United States)

    Chan, A. A.; Zheng, L.; O'Brien, T. P., III; Tu, W.; Cunningham, G.; Elkington, S. R.; Albert, J.

    2015-12-01

    Drift shell splitting in the radiation belts breaks all three adiabatic invariants of charged particle motion via pitch angle scattering, and produces new diffusion terms that fully populate the diffusion tensor in the Fokker-Planck equation. Based on the stochastic differential equation method, the Radbelt Electron Model (REM) simulation code allows us to solve such a fully three-dimensional Fokker-Planck equation, and to elucidate the sources and transport mechanisms behind the phase space density variations. REM has been used to perform simulations with an empirical initial phase space density followed by a seed electron injection, with a Tsyganenko 1989 magnetic field model, and with chorus wave and ULF wave diffusion models. Our simulation results show that adding drift shell splitting changes the phase space location of the source to smaller L shells, which typically reduces local electron energization (compared to neglecting drift-shell splitting effects). Simulation results with and without drift-shell splitting effects are compared with Van Allen Probe measurements.

  8. Upper limit on the inner radiation belt MeV electron intensity

    Science.gov (United States)

    Li, X; Selesnick, RS; Baker, DN; Jaynes, AN; Kanekal, SG; Schiller, Q; Blum, L; Fennell, J; Blake, JB

    2015-01-01

    No instruments in the inner radiation belt are immune from the unforgiving penetration of the highly energetic protons (tens of MeV to GeV). The inner belt proton flux level, however, is relatively stable; thus, for any given instrument, the proton contamination often leads to a certain background noise. Measurements from the Relativistic Electron and Proton Telescope integrated little experiment on board Colorado Student Space Weather Experiment CubeSat, in a low Earth orbit, clearly demonstrate that there exist sub-MeV electrons in the inner belt because their flux level is orders of magnitude higher than the background, while higher-energy electron (>1.6 MeV) measurements cannot be distinguished from the background. Detailed analysis of high-quality measurements from the Relativistic Electron and Proton Telescope on board Van Allen Probes, in a geo-transfer-like orbit, provides, for the first time, quantified upper limits on MeV electron fluxes in various energy ranges in the inner belt. These upper limits are rather different from flux levels in the AE8 and AE9 models, which were developed based on older data sources. For 1.7, 2.5, and 3.3 MeV electrons, the upper limits are about 1 order of magnitude lower than predicted model fluxes. The implication of this difference is profound in that unless there are extreme solar wind conditions, which have not happened yet since the launch of Van Allen Probes, significant enhancements of MeV electrons do not occur in the inner belt even though such enhancements are commonly seen in the outer belt. Key Points Quantified upper limit of MeV electrons in the inner belt Actual MeV electron intensity likely much lower than the upper limit More detailed understanding of relativistic electrons in the magnetosphere PMID:26167446

  9. Observational evidence of competing source, loss, and transport processes for relativistic electrons in Earth's outer radiation belt

    Science.gov (United States)

    Turner, Drew; Mann, Ian; Usanova, Maria; Rodriguez, Juan; Henderson, Mike; Angelopoulos, Vassilis; Morley, Steven; Claudepierre, Seth; Li, Wen; Kellerman, Adam; Boyd, Alexander; Kim, Kyung-Chan

    Earth’s outer electron radiation belt is a region of extreme variability, with relativistic electron intensities changing by orders of magnitude over time scales ranging from minutes to years. Extreme variations of outer belt electrons ultimately result from the relative impacts of various competing source (and acceleration), loss, and transport processes. Most of these processes involve wave-particle interactions between outer belt electrons and different types of plasma waves in the inner magnetosphere, and in turn, the activity of these waves depends on different solar wind and magnetospheric driving conditions and thus can vary drastically from event to event. Using multipoint analysis with data from NASA’s Van Allen Probes, THEMIS, and SAMPEX missions, NOAA’s GOES and POES constellations, and ground-based observatories, we present results from case studies revealing how different source/acceleration and loss mechanisms compete during active periods to result in drastically different distributions of outer belt electrons. By using a combination of low-Earth orbiting and high-altitude-equatorial orbiting satellites, we briefly review how it is possible to get a much more complete picture of certain wave activity and electron losses over the full range of MLTs and L-shells throughout the radiation belt. We then show example cases highlighting the importance of particular mechanisms, including: substorm injections and whistler-mode chorus waves for the source and acceleration of relativistic electrons; magnetopause shadowing and wave-particle interactions with EMIC waves for sudden losses; and ULF wave activity for driving radial transport, a process which is important for redistributing relativistic electrons, contributing both to acceleration and loss processes. We show how relativistic electron enhancement events involve local acceleration that is consistent with wave-particle interactions between a seed population of 10s to 100s of keV electrons, with a

  10. Variation of Natural Gamma Radiation in Isparta

    International Nuclear Information System (INIS)

    Akkurt, I.

    2004-01-01

    There is always a radiation in the earth, and its level is generated primarily by galactic cosmic rays (GCR), consisting of energetic nuclei of all naturally occurring elements, interacting with atmospheric constituents, through atomic and nuclear collisions. The other sources of natural radiations are global average background radiation from terrestrial sources such as soils, rocks ete. Background radiation levels in the atmosphere vary in intensity with latitude, altitude and phase of the solar cycle. Variation of natural radiation as a function of altitude, geological structure etc has been investigated. The measurements were performed using portable radiation counter which connected to NaI(Tl) probe

  11. 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.

  12. Study the Precipitation of Radiation Belt Electrons during the Rapid Dropout Events

    Science.gov (United States)

    Tu, W.; Cunningham, G.; Li, X.; Chen, Y.

    2015-12-01

    During the main phase of storms, the relativistic electron flux in the radiation belt can drop by orders of magnitude on timescales of a few hours. Where do the electrons go? This is one of the most important outstanding questions in radiation belt studies. Radiation belt electrons can be lost either by transport across the magnetopause into interplanetary space or by precipitation into the atmosphere. In this work we first conduct a survey of the MeV electron dropouts using the Van Allen Probes data in conjunction with the low-altitude measurements of precipitating electrons by 6 NOAA/POES satellites. The dropout events are categorized into three types: precipitation-loss dominant, outward radial diffusion dominant, or with contributions from both mechanisms. The survey results suggest the relative importance of precipitation and outward radial diffusion to the fast dropouts of radiation belt electrons, and their extent in L-shell and electron energy. Then, for specific events identified as dominated by precipitation loss, we use the Drift-Diffusion model, which includes the effects of azimuthal drift and pitch angle diffusion, to simulate both the electron dropout observed by Van Allen Probes and the distributions of drift-loss-cone electrons observed by multiple low-earth-orbit satellites (6 POES and the Colorado Student Space Weather Experiment). The model quantifies the electron precipitation loss and pitch angle diffusion coefficient, Dxx, with high temporal and spatial resolution. Finally, by comparing the Dxx derived from the model with those estimated from the quasi-linear theory using wave data from Van Allen Probes and other event-specific wave models, we are able to test the validity of quasi-linear theory and seek direct evidence of the wave-particle interactions during the dropouts.

  13. Effects of Electromagnetic Perturbations on Particles Trapped in the Radiation Belts

    Energy Technology Data Exchange (ETDEWEB)

    Dungey, J. W. [Imperial College of Science and Technology, London (United Kingdom)

    1965-06-15

    Since the radiation belts were discovered by Van Allen in 1958, observations of trapped particles have rapidly built up a large body of information. Knowledge of the neutral atmosphere as well as the ionosphere shows that for energetic particles the probable time before colliding with another particle of any kind may be extremely long. Then the only feature known to affect the motion of the particle is the electromagnetic field and, conversely, over a long time even weak electromagnetic disturbances can be important. Consequently, electromagnetic disturbances should be important in determining the form of the radiation belts, and it will be seen that certain features encourage an interpretation of this kind. The physics of the radiation belts may be regarded as a part of plasma physics, namely the realm in which collisions are negligible. This needs qualifying in that there is a boundary layer (the ionosphere) where collisions are important, and this is analogous to laboratory plasma containment devices. The energy range of trapped particles is wide, but includes the energy range required for fusion reactors. The mean free time in the radiation belts is extreme, but the neglect of collisions yields a great simplification in theoretical work, and an understanding of collision-free plasmas is expected to be useful. Observations in space have great advantages. The quantity measured by a particle-detector sensitive to a limited range of energy and with a limited cone of acceptance is the velocity distribution function, which is fundamental in theoretical work. Local electric and magnetic measurements are also made with very little disturbance by the spacecraft. The disadvantage is that simultaneous measurements cannot be made at many different points.

  14. 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 - others: 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

  15. A new Predictive Model for Relativistic Electrons in Outer Radiation Belt

    Science.gov (United States)

    Chen, Y.

    2017-12-01

    Relativistic electrons trapped in the Earth's outer radiation belt present a highly hazardous radiation environment for spaceborne electronics. These energetic electrons, with kinetic energies up to several megaelectron-volt (MeV), manifest a highly dynamic and event-specific nature due to the delicate interplay of competing transport, acceleration and loss processes. Therefore, developing a forecasting capability for outer belt MeV electrons has long been a critical and challenging task for the space weather community. Recently, the vital roles of electron resonance with waves (including such as chorus and electromagnetic ion cyclotron) have been widely recognized; however, it is still difficult for current diffusion radiation belt models to reproduce the behavior of MeV electrons during individual geomagnetic storms, mainly because of the large uncertainties existing in input parameters. In this work, we expanded our previous cross-energy cross-pitch-angle coherence study and developed a new predictive model for MeV electrons over a wide range of L-shells inside the outer radiation belt. This new model uses NOAA POES observations from low-Earth-orbits (LEOs) as inputs to provide high-fidelity nowcast (multiple hour prediction) and forecast (> 1 day prediction) of the energization of MeV electrons as well as the evolving MeV electron distributions afterwards during storms. Performance of the predictive model is quantified by long-term in situ data from Van Allen Probes and LANL GEO satellites. This study adds new science significance to an existing LEO space infrastructure, and provides reliable and powerful tools to the whole space community.

  16. Dynamics of Quasi-Electrostatic Whistler waves in Earth's Radiation belts

    Science.gov (United States)

    Goyal, R.; Sharma, R. P.; Gupta, D. N.

    2017-12-01

    A numerical model is proposed to study the dynamics of high amplitude quasi-electrostatic whistler waves propagating near resonance cone angle and their interaction with finite frequency kinetic Alfvén waves (KAWs) in Earth's radiation belts. The quasi-electrostatic character of whistlers is narrated by dynamics of wave propagating near resonance cone. A high amplitude whistler wave packet is obtained using the present analysis which has also been observed by S/WAVES instrument onboard STEREO. The numerical simulation technique employed to study the dynamics, leads to localization (channelling) of waves as well as turbulent spectrum suggesting the transfer of wave energy over a range of frequencies. The turbulent spectrum also indicates the presence of quasi-electrostatic whistlers and density fluctuations associated with KAW in radiation belts plasma. The ponderomotive force of pump quasi-electrostatic whistlers (high frequency) is used to excite relatively much lower frequency waves (KAWs). The wave localization and steeper spectra could be responsible for particle energization or heating in radiation belts.

  17. Application of multi-parameter chorus and plasmaspheric hiss wave models in radiation belt modeling

    Science.gov (United States)

    Aryan, H.; Kang, S. B.; Balikhin, M. A.; Fok, M. C. H.; Agapitov, O. V.; Komar, C. M.; Kanekal, S. G.; Nagai, T.; Sibeck, D. G.

    2017-12-01

    Numerical simulation studies of the Earth's radiation belts are important to understand the acceleration and loss of energetic electrons. The Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model along with many other radiation belt models require inputs for pitch angle, energy, and cross diffusion of electrons, due to chorus and plasmaspheric hiss waves. These parameters are calculated using statistical wave distribution models of chorus and plasmaspheric hiss amplitudes. In this study we incorporate recently developed multi-parameter chorus and plasmaspheric hiss wave models based on geomagnetic index and solar wind parameters. We perform CIMI simulations for two geomagnetic storms and compare the flux enhancement of MeV electrons with data from the Van Allen Probes and Akebono satellites. We show that the relativistic electron fluxes calculated with multi-parameter wave models resembles the observations more accurately than the relativistic electron fluxes calculated with single-parameter wave models. This indicates that wave models based on a combination of geomagnetic index and solar wind parameters are more effective as inputs to radiation belt models.

  18. Modeling radiation belt dynamics using a 3-D layer method code

    Science.gov (United States)

    Wang, C.; Ma, Q.; Tao, X.; Zhang, Y.; Teng, S.; Albert, J. M.; Chan, A. A.; Li, W.; Ni, B.; Lu, Q.; Wang, S.

    2017-08-01

    A new 3-D diffusion code using a recently published layer method has been developed to analyze radiation belt electron dynamics. The code guarantees the positivity of the solution even when mixed diffusion terms are included. Unlike most of the previous codes, our 3-D code is developed directly in equatorial pitch angle (α0), momentum (p), and L shell coordinates; this eliminates the need to transform back and forth between (α0,p) coordinates and adiabatic invariant coordinates. Using (α0,p,L) is also convenient for direct comparison with satellite data. The new code has been validated by various numerical tests, and we apply the 3-D code to model the rapid electron flux enhancement following the geomagnetic storm on 17 March 2013, which is one of the Geospace Environment Modeling Focus Group challenge events. An event-specific global chorus wave model, an AL-dependent statistical plasmaspheric hiss wave model, and a recently published radial diffusion coefficient formula from Time History of Events and Macroscale Interactions during Substorms (THEMIS) statistics are used. The simulation results show good agreement with satellite observations, in general, supporting the scenario that the rapid enhancement of radiation belt electron flux for this event results from an increased level of the seed population by radial diffusion, with subsequent acceleration by chorus waves. Our results prove that the layer method can be readily used to model global radiation belt dynamics in three dimensions.

  19. Three-dimensional data assimilation and reanalysis of radiation belt electrons: Observations over two solar cycles, and operational forecasting.

    Science.gov (United States)

    Kellerman, A. C.; Shprits, Y.; Kondrashov, D. A.; Podladchikova, T.; Drozdov, A.; Subbotin, D.; Makarevich, R. A.; Donovan, E.; Nagai, T.

    2015-12-01

    Understanding of the dynamics in Earth's radiation belts is critical to accurate modeling and forecasting of space weather conditions, both which are important for design, and protection of our space-borne assets. In the current study, we utilize the Versatile Electron Radiation Belt (VERB) code, multi-spacecraft measurements, and a split-operator Kalman filter to recontructe the global state of the radiation belt system in the CRRES era and the current era. The reanalysis has revealed a never before seen 4-belt structure in the radiation belts during the March 1991 superstorm, and highlights several important aspects in regards to the the competition between the source, acceleration, loss, and transport of particles. In addition to the above, performing reanalysis in adiabatic coordinates relies on specification of the Earth's magnetic field, and associated observational, and model errors. We determine the observational errors for the Kalman filter directly from cross-spacecraft phase-space density (PSD) conjunctions, and obtain the error in VERB by comparison with reanalysis over a long time period. Specification of errors associated with several magnetic field models provides an important insight into the applicability of such models for radiation belt research. The comparison of CRRES area reanalysis with Van Allen Probe era reanalysis allows us to perform a global comparison of the dynamics of the radiation belts during different parts of the solar cycle and during different solar cycles. The data assimilative model is presently used to perform operational forecasts of the radiation belts (http://rbm.epss.ucla.edu/realtime-forecast/).

  20. Three-dimensional data assimilation and reanalysis of radiation belt electrons: Observations of a four-zone structure using five spacecraft and the VERB code

    Science.gov (United States)

    Kellerman, A. C.; Shprits, Y. Y.; Kondrashov, D.; Subbotin, D.; Makarevich, R. A.; Donovan, E.; Nagai, T.

    2014-11-01

    Obtaining the global state of radiation belt electrons through reanalysis is an important step toward validating our current understanding of radiation belt dynamics and for identification of new physical processes. In the current study, reanalysis of radiation belt electrons is achieved through data assimilation of five spacecraft with the 3-D Versatile Electron Radiation Belt (VERB) code using a split-operator Kalman filter technique. The spacecraft data are cleaned for noise, saturation effects, and then intercalibrated on an individual energy channel basis, by considering phase space density conjunctions in the T96 field model. Reanalysis during the CRRES era reveals a never-before-reported four-zone structure in the Earth's radiation belts during the 24 March 1991 shock-induced injection superstorm: (1) an inner belt, (2) the high-energy shock-injection belt, (3) a remnant outer radiation belt, and (4) a second outer radiation belt. The third belt formed near the same time as the second belt and was later enhanced across keV to MeV energies by a second particle injection observed by CRRES and the Northern Solar Terrestrial Array riometer network. During the recovery phase of the storm, the fourth belt was created near L*=4RE, lasting for several days. Evidence is provided that the fourth belt was likely created by a dominant local heating process. This study outlines the necessity to consider all diffusive processes acting simultaneously and the advantage of supporting ground-based data in quantifying the observed radiation belt dynamics. It is demonstrated that 3-D data assimilation can resolve various nondiffusive processes and provides a comprehensive picture of the electron radiation belts.

  1. To the problem on a charge state of energetic ions of radiation belts

    International Nuclear Information System (INIS)

    Panasyuk, M.I.

    1980-01-01

    Estimation of the effect of recharging processes upon formation of intensity maxima of radiation belt ions of different types is obtained as well as the ion charge states in the area of intensity maxima. Comparison of spatial position of intensity maxima of the H, He, C, O ions with the energies more than 1 MeV with the calculation results is presented. It provides the particle radial drift under the effect of sudden impulses and death at the expence of ionization losses. Application of adiabaticity criterion of the particle movement to the analysis of position of outer edge of radiation belt of heavy ions permitted to carry out estimation of the He, C, O ion charge state. He ions with the energy more than 1 MeV possess mainly the charge state of +2, C and O ions with the energy of several MeV over L=5-6 are in the ionized state almost completely, and during the drift into the depth of the belts the ion charge decreases to 3-4 over L approximately 3.5 with the energy increase. At the energies higher than several MeV the recharge processes are significant for the C and.O ions. For He ions with the energy higher 1 MeV and for H ions with more than 0.1 MeV the recharge role is not considerable

  2. Empirical radiation belt models: Comparison with in situ data and implications for environment definition

    Science.gov (United States)

    de Soria-Santacruz Pich, Maria; Jun, Insoo; Evans, Robin

    2017-09-01

    The empirical AP8/AE8 model has been the de facto Earth's radiation belts engineering reference for decades. The need from the community for a better model incubated the development of AP9/AE9/SPM, which addresses several shortcomings of the old model. We provide additional validation of AP9/AE9 by comparing in situ electron and proton data from Jason-2, Polar Orbiting Environmental Satellites (POES), and the Van Allen Probes spacecraft with the 5th, 50th, and 95th percentiles from AE9/AP9 and with the model outputs from AE8/AP8. The relatively short duration of Van Allen Probes and Jason-2 missions means that their measurements are most certainly the result of specific climatological conditions. In low Earth orbit (LEO), the Jason-2 proton flux is better reproduced by AP8 compared to AP9, while the POES electron data are well enveloped by AE9 5th and 95th percentiles. The shape of the South Atlantic anomaly (SAA) from Jason-2 data is better captured by AP9 compared to AP8, while the peak SAA flux is better reproduced by AP8. The <1.5 MeV inner belt electrons from Magnetic Electron Ion Spectrometer (MagEIS) are well enveloped by AE9 5th and 95th percentiles, while AE8 overpredicts the measurements. In the outer radiation belt, MagEIS and Relativistic Electron and Proton Telescope (REPT) electrons closely follow the median estimate from AE9, while AP9 5th and 95th percentiles generally envelope REPT proton measurements in the inner belt and slot regions. While AE9/AP9 offer the flexibility to specify the environment with different confidence levels, the dose and trapped proton peak flux for POES and Jason-2 trajectories from the AE9/AP9 50th percentile and above are larger than the estimates from the AE8/AP8 models.

  3. Electron flux enhancement in the inner radiation belt during moderate magnetic storms

    Directory of Open Access Journals (Sweden)

    H. Tadokoro

    2007-06-01

    Full Text Available During moderate magnetic storms, an electron channel (300–1100 keV of the NOAA satellite has shown sudden electron flux enhancements in the inner radiation belt. After examinating the possibility of contamination by different energetic particles, we conclude that these electron flux enhancements are reliable enough to be considered as natural phenomena, at least for the cases of small to moderate magnetic storms. Here, we define small and moderate storms to be those in which the minimum Dst ranges between −30 and −100 nT. The electron flux enhancements appear with over one order of magnitude at L~2 during these storms. The enhancement is not accompanied by any transport of electron flux from the outer belt. Statistical analysis shows that these phenomena have a duration of approximately 1 day during the period, starting with the main phase to the early recovery phase of the storms. The flux enhancement shows a dawn-dusk asymmetry; the amount of increased flux is larger in the dusk side. We suggest that this phenomenon could not be caused by the radial diffusion but would be due to pitch-angle scattering at the magnetic equator. The inner belt is not in a stationary state, as was previously believed, but is variable in response to the magnetic activity.

  4. The Magnetic Local Time Distribution of Energetic Electrons in the Radiation Belt Region

    Science.gov (United States)

    Allison, H. J.

    2017-12-01

    Using fourteen years of electron flux data from the National Oceanic and Atmospheric Administration Polar Operational Environmental Satellites (POES), a statistical study of the magnetic local time (MLT) distribution of the electron population is performed across a range of activity levels, defined by AE, AE*, Kp, solar wind velocity (Vsw), and VswBz. Three electron energies (>30, >100, and >300 keV) are considered. Dawn-dusk flux asymmetries larger than order of magnitude were observed for >30 and >100 keV electrons. For >300 keV electrons, dawn-dusk asymmetries were primarily due to a decrease in the average dusk-side flux beyond L* ˜ 4.5 that arose with increasing activity. For the >30 keV population, substorm injections enhance the dawn-side flux, which may not reach the dusk-side as the electrons can be on open drift paths and lost to the magnetopause. The asymmetries in the >300 keV population are attributed to the combination of magnetopause shadowing and >300 keV electron injections by large electric fields. We suggest that 3D radiation belt models could set the minimum energy boundary (Emin) to 30 keV or above at L* ˜6 during periods of low activity. However, for more moderate conditions, Emin should be larger than 100 keV and, for very extreme activities, ˜300 keV. Our observations show the extent that in-situ electron flux readings may vary during active periods due to the MLT of the satellite and highlight the importance of 4D radiation belt models to fully understand radiation belt processes.

  5. Multi-Point Measurements to Characterize Radiation Belt Electron Precipitation Loss

    Science.gov (United States)

    Blum, L. W.

    2017-12-01

    Multipoint measurements in the inner magnetosphere allow the spatial and temporal evolution of various particle populations and wave modes to be disentangled. To better characterize and quantify radiation belt precipitation loss, we utilize multi-point measurements both to study precipitating electrons directly as well as the potential drivers of this loss process. Magnetically conjugate CubeSat and balloon measurements are combined to estimate of the temporal and spatial characteristics of dusk-side precipitation features and quantify loss due to these events. To then understand the drivers of precipitation events, and what determines their spatial structure, we utilize measurements from the dual Van Allen Probes to estimate spatial and temporal scales of various wave modes in the inner magnetosphere, and compare these to precipitation characteristics. The structure, timing, and spatial extent of waves are compared to those of MeV electron precipitation during a few individual events to determine when and where EMIC waves cause radiation belt electron precipitation. Magnetically conjugate measurements provide observational support of the theoretical picture of duskside interaction of EMIC waves and MeV electrons leading to radiation belt loss. Finally, understanding the drivers controlling the spatial scales of wave activity in the inner magnetosphere is critical for uncovering the underlying physics behind the wave generation as well as for better predicting where and when waves will be present. Again using multipoint measurements from the Van Allen Probes, we estimate the spatial and temporal extents and evolution of plasma structures and their gradients in the inner magnetosphere, to better understand the drivers of magnetospheric wave characteristic scales. In particular, we focus on EMIC waves and the plasma parameters important for their growth, namely cold plasma density and cool and warm ion density, anisotropy, and composition.

  6. Quantifying the Precipitation Loss of Radiation Belt Electrons during a Rapid Dropout Event

    Science.gov (United States)

    Pham, K. H.; Tu, W.; Xiang, Z.

    2017-12-01

    Relativistic electron flux in the radiation belt can drop by orders of magnitude within the timespan of hours. In this study, we used the drift-diffusion model that includes azimuthal drift and pitch angle diffusion of electrons to simulate low-altitude electron distribution observed by POES/MetOp satellites for rapid radiation belt electron dropout event occurring on May 1, 2013. The event shows fast dropout of MeV energy electrons at L>4 over a few hours, observed by the Van Allen Probes mission. By simulating the electron distributions observed by multiple POES satellites, we resolve the precipitation loss with both high spatial and temporal resolution and a range of energies. We estimate the pitch angle diffusion coefficients as a function of energy, pitch angle, and L-shell, and calculate corresponding electron lifetimes during the event. The simulation results show fast electron precipitation loss at L>4 during the electron dropout, with estimated electron lifetimes on the order of half an hour for MeV energies. The electron loss rate show strong energy dependence with faster loss at higher energies, which suggest that this dropout event is dominated by quick and localized scattering process that prefers higher energy electrons. The estimated pitch angle diffusion rates from the model are then compared with in situ wave measurements from Van Allen Probes to uncover the underlying wave-particle-interaction mechanisms that are responsible for the fast electron precipitation. Comparing the resolved precipitation loss with the observed electron dropouts at high altitudes, our results will suggest the relative role of electron precipitation loss and outward radial diffusion to the radiation belt dropouts during storm and non-storm times, in addition to its energy and L dependence.

  7. Modelling formation of new radiation belts and response to ULF oscillations following March 24, 1991 SSC

    International Nuclear Information System (INIS)

    Hudson, M.K.; Kotelnikov, A.D.; Li, X.; Lyon, J.G.; Roth, I.; Temerin, M.; Wygant, J.R.; Blake, J.B.; Gussenhoven, M.S.; Yumoto, K.; Shiokawa, K.

    1996-01-01

    The rapid formation of a new proton radiation belt at L≅2.5 following the March 24, 1991 Storm Sudden Commencement (SSC) observed at the CRRES satellite is modelled using a relativistic guiding center test particle code. The new radiation belt formed on a time scale shorter than the drift period of eg. 20 MeV protons. The SSC is modelled by a bipolar electric field and associated compression and relaxation in the magnetic field, superimposed on a background dipole magnetic field. The source population consists of solar protons that populated the outer magnetosphere during the solar proton event that preceeded the SSC and trapped inner zone protons. The simulations show that both populations contribute to drift echoes in the 20 endash 80 MeV range measured by the Aerospace instrument and in lower energy channels of the Protel instrument on CRRES, while primary contribution to the newly trapped population is from solar protons. Proton acceleration by the SSC differs from electron acceleration in two notable ways: different source populations contribute and nonrelativistic conservation of the first adiabatic invariant leads to greater energization of protons for a given decrease in L than for relativistic electrons. Model drift echoes, energy spectra and flux distribution in L at the time of injection compare well with CRRES observations. On the outbound pass, ∼2 hours after the SSC, the broad spectral peak of the new radiation belt extends to higher energies (20 endash 40 MeV) than immediately after formation. Electron flux oscillations observed at this later time are attributed to post-SSC impulses evident in ground magnetograms, while two minute period ULF oscillations also evident in CRRES field data appear to be cavity modes in the inner magnetosphere. copyright 1996 American Institute of Physics

  8. 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.

  9. A virtual radiation belt observatory: Looking forward to the electronic geophysical year

    Science.gov (United States)

    Baker, D. N.; Green, J. C.; Kroehl, H. W.; Kihn, E.; Virbo Team

    During the International Geophysical Year (1957-1958), member countries established many new capabilities pursuing the major IGY objectives of collecting geophysical data as widely as possible and providing free access to these data for all scientists around the globe. A key achievement of the IGY was the establishment of a worldwide system of data centers and physical observatories. The worldwide scientific community has now endorsed and is promoting an electronic Geophysical Year (eGY) initiative. The proposed eGY concept would both commemorate the 50th anniversary of the IGY in 2007-2008 and would provide a forward impetus to geophysics in the 21st century, similar to that provide by the IGY fifty years ago. The eGY concept advocates the establishment of a series of virtual geophysical observatories now being deployed in cyberspace. We are developing the concept of a Virtual Radiation Belt Observatory (ViRBO) that will bring together near-earth particle and field measurements acquired by NASA, NOAA, DoD, DOE, and other spacecraft. We discuss plans to aggregate these measurements into a readily accessible database along with analysis, visualization, and display tools that will make radiation belt information available and useful both to the scientific community and to the user community. We envision that data from the various agencies along with models being developed under the auspices of the National Science Foundation Center for Integrated Space Weather Modeling (CISM) will help us to provide an excellent `climatology' of the radiation belts over the past several decades. In particular, we would plan to use these data to drive physical models of the radiation belts to form a gridded database which would characterize particle and field properties on solar-cycle (11-year) time scales. ViRBO will also provide up-to-date specification of conditions for event analysis and anomaly resolution. We are even examining the possibilities for near-realtime acquisition of

  10. Mass spectrometer determinations of solar wind He, Ne, and Ar and radiation belt He

    International Nuclear Information System (INIS)

    Warasila, R.L.

    1976-01-01

    A unique mass spectrometer system was built and used to measure He, Ne, and Ar abundances and isotopic ratios in various samples of spacecraft that have been exposed to the space environment. The Apollo 12 mission brought back sections of the Surveyor 3 vehicle suitable for mass spectrometric studies of implanted solar wind and solar cosmic ray particles. Using the mass spectrometer, a 4 He flux of 6-8 x 10 6 ions/cm 2 --sec was measured, and in addition 4 He/ 3 He = 2700 +- 50; 4 He/ 20 Ne = 410 + 30; 20 Ne/ 22 Ne = 13.5 +- 0.2; 20 Ne/ 36 Ar = 24.5 +- 2.5; and 36 Ar/ 38 Ar = 5.41 +- 0.20 isotopic abundances were measured. An upper limit for the flux of SCR 3 He in the 10-20 MeV/nucleon range was also determined, for the thirty-one month exposure period. In the radiation belt environment, 3 He was found in the aluminum antenna housing from the recovered second stage of a pre-Apollo Saturn test flight launched January 28, 1964 and returned to earth on April 28, 1966. The amount of 3 He found was about 6 x 10 -10 cc(STP)/cm 2 with a 4 He/ 3 He ratio of 145 or less. The 3 He was shown to come from the lower radiation belt as all other sources of 3 He were orders of magnitude lower than the observed value

  11. Modeling the Proton Radiation Belt With Van Allen Probes Relativistic Electron-Proton Telescope Data

    Science.gov (United States)

    Selesnick, R. S.; Baker, D. N.; Kanekal, S. G.; Hoxie, V. C.; Li, X.

    2018-01-01

    An empirical model of the proton radiation belt is constructed from data taken during 2013-2017 by the Relativistic Electron-Proton Telescopes on the Van Allen Probes satellites. The model intensity is a function of time, kinetic energy in the range 18-600 MeV, equatorial pitch angle, and L shell of proton guiding centers. Data are selected, on the basis of energy deposits in each of the nine silicon detectors, to reduce background caused by hard proton energy spectra at low L. Instrument response functions are computed by Monte Carlo integration, using simulated proton paths through a simplified structural model, to account for energy loss in shielding material for protons outside the nominal field of view. Overlap of energy channels, their wide angular response, and changing satellite orientation require the model dependencies on all three independent variables be determined simultaneously. This is done by least squares minimization with a customized steepest descent algorithm. Model uncertainty accounts for statistical data error and systematic error in the simulated instrument response. A proton energy spectrum is also computed from data taken during the 8 January 2014 solar event, to illustrate methods for the simpler case of an isotropic and homogeneous model distribution. Radiation belt and solar proton results are compared to intensities computed with a simplified, on-axis response that can provide a good approximation under limited circumstances.

  12. HEPD on NEXTSat-1: A High Energy Particle Detector for Measurements of Precipitating Radiation Belt Electrons

    Science.gov (United States)

    Sohn, Jongdae; Lee, Jaejin; Min, Kyoungwook; Lee, Junchan; Lee, Seunguk; Lee, Daeyoung; Jo, Gyeongbok; Yi, Yu; Na, Gowoon; Kang, Kyung-In; Shin, Goo-Hwan

    2018-05-01

    Radiation belt particles of the inner magnetosphere precipitate into the atmosphere in the subauroral regions when they are pitch-angle scattered into the loss cone by wave-particle interactions. Such particle precipitations are known to be especially enhanced during space storms, though they can also occur during quiet times. The observed characteristics of precipitating electrons can be distinctively different, in their time series as well as in their spectra, depending on the waves involved. The present paper describes the High Energy Particle Detector (HEPD) on board the Next Generation Small Satellite-1 (NEXTSat-1), which will measure these radiation belt electrons from a low-Earth polar orbit satellite to study the mechanisms related to electron precipitation in the sub-auroral regions. The HEPD is based on silicon barrier detectors and consists of three telescopes that are mounted on the satellite to have angles of 0°. 45°, and 90°, respectively with the local geomagnetic field during observations. With a high time resolution of 32 Hz and a high spectral resolution of 11 channels over the energy range from 350 keV to 2 MeV, together with the pitch angle information provided by the three telescopes, HEPD is capable of identifying physical processes, such as microbursts and dust-side relativistic electron precipitation (DREP) events associated with electron precipitations. NextSat-1 is scheduled for launch in early 2018.

  13. Wave-Particle Interactions in the Earth's Radiation Belts: Recent Advances and Unprecedented Future Opportunities

    Science.gov (United States)

    Li, W.

    2017-12-01

    In the collisionless heliospheric plasmas, wave-particle interaction is a fundamental physical process in transferring energy and momentum between particles with different species and energies. This presentation focuses on one of the important wave-particle interaction processes: interaction between whistler-mode waves and electrons. Whistler-mode waves have frequencies between proton and electron cyclotron frequency and are ubiquitously present in the heliospheric plasmas including solar wind and planetary magnetospheres. I use Earth's Van Allen radiation belt as "local space laboratory" to discuss the role of whistler-mode waves in energetic electron dynamics using multi-satellite observations, theory and modeling. I further discuss solar wind drivers leading to energetic electron dynamics in the Earth's radiation belts, which is critical in predicting space weather that has broad impacts on our technological systems and society. At last, I discuss the unprecedented future opportunities of exploring space science using multi-satellite observations and state-of-the-art theory and modeling.

  14. 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

    2015-05-15

    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.

  15. 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.

  16. Storm-time electron flux precipitation in the inner radiation belt caused by wave-particle interactions

    Directory of Open Access Journals (Sweden)

    H. Tadokoro

    2009-04-01

    Full Text Available It has been believed that electrons in the inner belt do not show the dynamical variation during magnetic storms except for great magnetic storms. However, Tadokoro et al. (2007 recently disclosed that low-altitude electrons in the inner belt frequently show flux variations during storms (Storm Time inner belt Electron Enhancement at the Low altitude (STEEL. This paper investigates a possible mechanism explaining STEEL during small and moderate storms, and shows that it is caused not by radial transport processes but by pitch angle scattering through wave-particle interactions. The waves related to wave-particle interactions are attributed to be banded whistler mode waves around 30 kHz observed in the inner magnetosphere by the Akebono satellite. The estimated pitch angle distribution based on a numerical calculation is roughly consistent with the observed results.

  17. Relativistic electrons of the outer radiation belt and methods of their forecast (review

    Directory of Open Access Journals (Sweden)

    Potapov A.S.

    2017-03-01

    Full Text Available The paper reviews studies of the dynamics of relativistic electrons in the geosynchronous region. It lists the physical processes that lead to the acceleration of electrons filling the outer radiation belt. As one of the space weather factors, high-energy electron fluxes pose a serious threat to the operation of satellite equipment in one of the most populated orbital regions. Necessity is emphasized for efforts to develop methods for forecasting the situation in this part of the magnetosphere, possible predictors are listed, and their classification is given. An example of a predictive model for forecasting relativistic electron flux with a 1–2-day lead time is proposed. Some questions of practical organization of prediction are discussed; the main objectives of short-term, medium-term, and long-term forecasts are listed.

  18. 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.; hide

    2016-01-01

    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, sing 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 (C) and interplanetary structure sunward of the MC had primarily northward magnetic field, perhaps leading to a concomitant lack of substorm activity and a 10 day long 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 5.5can 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 shownto be viable mechanisms.

  19. Wave-Particle Interactions in the Radiation Belts, Aurora,and Solar Wind: Opportunities for Lab Experiments

    Science.gov (United States)

    Kletzing, C.

    2017-12-01

    The physics of the creation, loss, and transport of radiation belt particles is intimately connected to the electric and magnetic fields which mediate these processes. A large range of field and particle interactions are involved in this physics from large-scale ring current ion and magnetic field dynamics to microscopic kinetic interactions of whistler-mode chorus waves with energetic electrons. To measure these kinds of radiation belt interactions, NASA implemented the two-satellite Van Allen Probes mission. As part of the mission, the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) investigation is an integrated set of instruments consisting of a triaxial fluxgate magnetometer (MAG) and a Waves instrument which includes a triaxial search coil magnetometer (MSC). We show a variety of waves thought to be important for wave particle interactionsin the radiation belts: low frequency ULF pulsations, EMIC waves, and whistler mode waves including upper and lower band chorus. Outside ofthe radiation belts, Alfven waves play a key role in both solar wind turbulenceand auroral particle acceleration. Several of these wave modes could benefit (or have benefitted) from laboratory studies to further refineour understanding of the detailed physics of the wave-particle interactionswhich lead to energization, pitch angle scattering, and cross-field transportWe illustrate some of the processes and compare the wave data with particle measurements to show relationships between wave activity and particle processobserved in the inner magnetosphere and heliosphere.

  20. Combined convective and diffusive modeling of the ring current and radiation belt electron dynamics using the VERB-4D code

    Science.gov (United States)

    Aseev, N.; Shprits, Y.; Drozdov, A.; Kellerman, A. C.; Wang, D.

    2017-12-01

    Ring current and radiation belts are key elements in the global dynamics of the Earth's magnetosphere. Comprehensive mathematical models are useful tools that allow us to understand the multiscale dynamics of these charged particle populations. In this work, we present results of simulations of combined ring current - radiation belt electron dynamics using the four-dimensional Versatile Electron Radiation Belt (VERB-4D) code. The VERB-4D code solves the modified Fokker-Planck equation including convective terms and models simultaneously ring current (1 - 100 keV) and radiation belt (100 keV - several MeV) electron dynamics. We apply the code to the number of geomagnetic storms that occurred in the past, compare the results with different satellite observations, and show how low-energy particles can affect the high-energy populations. Particularly, we use data from Polar Operational Environmental Satellite (POES) mission that provides a very good MLT coverage with 1.5-hour time resolution. The POES data allow us to validate the approach of the VERB-4D code for modeling MLT-dependent processes such as electron drift, wave-particle interactions, and magnetopause shadowing. We also show how different simulation parameters and empirical models can affect the results, making a particular emphasis on the electric and magnetic field models. This work will help us reveal advantages and disadvantages of the approach behind the code and determine its prediction efficiency.

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

    International Nuclear Information System (INIS)

    Li, W.; Ma, Q.; Thorne, R. M.; Bortnik, J.; Zhang, X.-J.

    2016-01-01

    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.

  2. Loss and source mechanisms of Jupiter's radiation belts near the inner boundary of trapping regions

    Science.gov (United States)

    Santos-Costa, Daniel; Bolton, Scott J.; Becker, Heidi N.; Clark, George; Kollmann, Peter; Paranicas, Chris; Mauk, Barry; Joergensen, John L.; Adriani, Alberto; Thorne, Richard M.; Bagenal, Fran; Janssen, Mike A.; Levin, Steve M.; Oyafuso, Fabiano A.; Williamson, Ross; Adumitroaie, Virgil; Ingersoll, Andrew P.; Kurth, Bill; Connerney, John E. P.

    2017-04-01

    We have merged a set of physics-based and empirical models to investigate the energy and spatial distributions of Jupiter's electron and proton populations in the inner and middle magnetospheric regions. Beyond the main source of plasma (> 5 Rj) where interchange instability is believed to drive the radial transport of charged particles, the method originally developed by Divine and Garrett [J. Geophys. Res., 88, 6889-6903, 1983] has been adapted. Closer to the planet where field fluctuations control the radial transport, a diffusion theory approach is used. Our results for the equatorial and mid-latitude regions are compared with Pioneer and Galileo Probe measurements. Data collected along Juno's polar orbit allow us to examine the features of Jupiter's radiation environment near the inner boundary of trapping regions. Significant discrepancies between Juno (JEDI keV energy particles and high energy radiation environment measurements made by Juno's SRU and ASC star cameras and the JIRAM infrared imager) and Galileo Probe data sets and models are observed close to the planet. Our simulations of Juno MWR observations of Jupiter's electron-belt emission confirm the limitation of our model to realistically depict the energy and spatial distributions of the ultra-energetic electrons. In this paper, we present our modeling approach, the data sets and resulting data-model comparisons for Juno's first science orbits. We describe our effort to improve our models of electron and proton belts. To gain a physical understanding of the dissimilarities with observations, we revisit the magnetic environment and the mechanisms of loss and source in our models.

  3. High Altitude Balloons as a Platform for Space Radiation Belt Science

    Science.gov (United States)

    Mazzino, L.; Buttenschoen, A.; Farr, Q.; Hodgson, C.; Johnson, W.; Mann, I. R.; Rae, J.; University of Alberta High Altitude Balloons (UA-HAB)

    2011-12-01

    The goals of the University of Alberta High Altitude Balloons Program (UA-HAB) are to i) use low cost balloons to address space radiation science, and ii) to utilise the excitement of "space mission" involvement to promote and facilitate the recruitment of undergraduate and graduate students in physics, engineering, and atmospheric sciences to pursue careers in space science and engineering. The University of Alberta High Altitude Balloons (UA-HAB) is a unique opportunity for University of Alberta students (undergraduate and graduate) to engage in the hands-on design, development, build, test and flight of a payload to operate on a high altitude balloon at around 30km altitude. The program development, including formal design and acceptance tests, reports and reviews, mirror those required in the development of an orbital satellite mission. This enables the students to gain a unique insight into how space missions are flown. UA-HAB is a one and half year program that offers a gateway into a high-altitude balloon mission through hands on experience, and builds skills for students who may be attracted to participate in future space missions in their careers. This early education will provide students with the experience necessary to better assess opportunities for pursuing a career in space science. Balloons offer a low-cost alternative to other suborbital platforms which can be used to address radiation belt science goals. In particular, the participants of this program have written grant proposal to secure funds for this project, have launched several 'weather balloon missions', and have designed, built, tested, and launched their particle detector called "Maple Leaf Particle Detector". This detector was focussed on monitoring cosmic rays and space radiation using shielded Geiger tubes, and was flown as one of the payloads from the institutions participating in the High Altitude Student Platform (HASP), organized by the Louisiana State University and the Louisiana

  4. Characteristics of pitch angle distributions of hundreds of keV electrons in the slot region and inner radiation belt

    Science.gov (United States)

    Zhao, H.; Li, X.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Baker, D. N.; Jaynes, A. N.; Malaspina, D. M.

    2014-12-01

    The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-the-art pitch angle-resolved data from the Magnetic Electron Ion Spectrometer instrument onboard the Van Allen Probes, a detailed analysis of hundreds of keV electron PADs below L = 4 is performed, in which the PADs are categorized into three types: normal (flux peaking at 90°), cap (exceedingly peaking narrowly around 90°), and 90° minimum (lower flux at 90°) PADs. By examining the characteristics of the PADs of ˜460 keV electrons for over a year, we find that the 90° minimum PADs are generally present in the inner belt (Lpitch angle scattering of hiss waves. Fitting the normal PADs into sinnα form, the parameter n is much higher below L = 3 than that in the outer belt and relatively constant in the inner belt but changes significantly in the slot region (2 mechanism can hardly explain the formation of 90° minimum PADs at the center of inner belt.

  5. 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.

    2015-01-01

    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 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. PMID:25975615

  6. Genetic variation in resistance to ionizing radiation

    International Nuclear Information System (INIS)

    Ayala, F.J.

    1991-01-01

    We proposed an investigation of genetically-determined individual differences in sensitivity to ionizing radiation. The model organism is Drosophila melanogaster. The gene coding for Cu,Zn superoxide dismutase (SOD) is the target locus, but the effects of variation in other components of the genome that modulate SOD levels are also taken into account. SOD scavenges oxygen radicals generated during exposure to ionizing radiation. It has been shown to protect against ionizing radiation damage to DNA, viruses, bacteria, mammalian cells, whole mice, and Drosophila. Two alleles, S and F, are commonly found in natural populations of D. melanogaster; in addition we have isolated from a natural population ''null'' (CA1) mutant that yields only 3.5% of normal SOD activity. The S, F, and CA1 alleles provide an ideal model system to investigate SOD-dependent radioresistance, because each allele yields different levels of SOD, so that S > F >> CA1. The roles of SOD level in radioresistance are being investigated in a series of experiments that measure the somatic and germ-line effects of increasing doses of ionizing radiation. In addition, we have pursued an unexpected genetic event-namely the nearly simultaneous transformation of several lines homozygous for the SOD ''null'' allele into predominately S lines. Using specifically designed probes and DNA amplification by means of the Tag polymerase chain reaction (PCR) we have shown that (1) the null allele was still present in the transformed lines, but was being gradually replaced by the S allele as a consequence of natural selection; and (2) that the transformation was due to the spontaneous deletion of a 0.68 Kb truncated P-element, the insertion of which is characteristic of the CA1 null allele

  7. 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

  8. Reanalyses of the radiation belt electron phase space density using nearly equatorial CRRES and polar-orbiting Akebono satellite observations

    Science.gov (United States)

    Ni, Binbin; Shprits, Yuri; Nagai, Tsugunobu; Thorne, Richard; Chen, Yue; Kondrashov, Dmitri; Kim, Hee-jeong

    2009-05-01

    Data assimilation techniques provide algorithms that allow for blending of incomplete and inaccurate data with physics-based dynamic models to reconstruct the electron phase space density (PSD) in the radiation belts. In this study, we perform reanalyses of the radial PSD profile using two independent data sources from the nearly equatorial CRRES Medium Electron A (MEA) observations and the polar-orbiting Akebono Radiation Monitor (RDM) measurements for a 50-day period from 18 August to 6 October 1990. We utilize the University of California, Los Angeles, One-Dimensional Versatile Electron Radiation Belt (UCLA 1-D VERB) code and a Kalman filtering approach. Comparison of the reanalyses obtained independently using the CRRES MEA and Akebono RDM measurements shows that the dynamics of the PSD can be accurately reconstructed using Kalman filtering even when available data are sparse, inaccurate, and contaminated by random errors. The reanalyses exhibit similarities in the locations and magnitudes of peaks in radial profiles of PSD and the rate and radial extent of the dropouts during storms. This study shows that when unidirectional data are not available, pitch angle averaged flux measurements can be used to infer the long-term behavior (climatology) of the radiation belts. The methodology of obtaining PSD from pitch angle averaged and unidirectional fluxes using the Tsyganenko and Stern (1996) magnetic field model is described in detail.

  9. Transport, charge exchange and loss of energetic heavy ions in the earth's radiation belts - Applicability and limitations of theory

    Science.gov (United States)

    Spjeldvik, W. N.

    1981-01-01

    Computer simulations of processes which control the relative abundances of ions in the trapping regions of geospace are compared with observations from discriminating ion detectors. Energy losses due to Coulomb collisions between ions and exospheric neutrals are considered, along with charge exchange losses and internal charge exchanges. The time evolution of energetic ion fluxes of equatorially mirroring ions under radial diffusion is modelled to include geomagnetic and geoelectric fluctutations. Limits to the validity of diffusion transport theory are discussed, and the simulation is noted to contain provisions for six ionic charge states and the source effect on the radiation belt oxygen ion distributions. Comparisons are made with ion flux data gathered on Explorer 45 and ISEE-1 spacecraft and results indicate that internal charge exchanges cause the radiation belt ion charge state to be independent of source charge rate characteristics, and relative charge state distribution is independent of the radially diffusive transport rate below the charge state redistribution zone.

  10. Neoclassical Diffusion of Radiation-Belt Electrons Across Very Low L-Shells

    Science.gov (United States)

    Cunningham, Gregory S.; Loridan, Vivien; Ripoll, Jean-François; Schulz, Michael

    2018-04-01

    In the presence of drift-shell splitting intrinsic to the International Geomagnetic Reference Field magnetic field model, pitch angle scattering from Coulomb collisions experienced by radiation-belt electrons in the upper atmosphere and ionosphere produces extra radial diffusion, a form of neoclassical diffusion. The strength of the neoclassical radial diffusion at L nuclear detonation. The data show apparent lifetimes 10-100 times as long as would have been expected from collisional pitch angle diffusion and Coulomb drag alone. Our model reproduces apparent lifetimes for >0.5-MeV electrons in the region 1.14 < L < 1.26 to within a factor of 2 (comparable to the uncertainty quoted for the observations). We conclude that neoclassical radial diffusion (resulting from drift-shell splitting intrinsic to International Geomagnetic Reference Field's azimuthal asymmetries) mitigates the decay expected from collisional pitch angle diffusion and inelastic energy loss alone and thus contributes importantly to the long apparent lifetimes observed at these low L-shells.

  11. Solar cyclic behavior of trapped energetic electrons in Earth's inner radiation belt

    Science.gov (United States)

    Abel, Bob; Thorne, Richard M.

    1994-10-01

    Magnetic electron spectrometer data from six satellites (OV3-3, OV1-14, OGO 5, S3-2, S3-3, and CRRES) have been used to study long-term (1966-1991) behavior of trapped energetic electrons in the inner radiation belt. Comparison of the observed energy spectra at L equal to or greater than 1.35 for different phases of the solar cycle reveals a clear trend toward enhanced fluxes during periods of solar maximum for energies below a few hundred keV; we suggest that this is caused by an increase in the rate of inward radial diffusion from a source at higher L. In contrast, for L less than 1.30, where atmospheric collisions become increasingly important, the electron flux is reduced during solar maximum; we attribute this to the expected increase in upper atmospheric densities. The electron flux above 1 MeV exhibits a systematic decay beyond 1979 to values well below the current NASA AE-8 model. This indicates that the natural background of high-energy electrons has previously been overestimated due to the long lasting presence of electrons produced by nuclear detonations in the upper atmosphere in the late 1950s and early 1960s.

  12. Multiple loss processes of relativistic electrons outside the heart of outer radiation belt during a storm sudden commencement

    International Nuclear Information System (INIS)

    Yu, J.

    2015-01-01

    By examining the compression-induced changes in the electron phase space density and pitch angle distribution observed by two satellites of Van Allen Probes (RBSP-A/B), we find that the relativistic electrons (>2 MeV) outside the heart of outer radiation belt (L*≥5) undergo multiple losses during a storm sudden commencement. The relativistic electron loss mainly occurs in the field-aligned direction (pitch angle α < 30° or >150°), and the flux decay of the field-aligned electrons is independent of the spatial location variations of the two satellites. However, the relativistic electrons in the pitch angle range of 30°–150° increase (decrease) with the decreasing (increasing) geocentric distance (|ΔL|<0.25) of the RBSP-B (RBSP-A) location, and the electron fluxes in the quasi-perpendicular direction display energy-dispersive oscillations in the Pc5 period range (2–10 min). The relativistic electron loss is confirmed by the decrease of electron phase space density at high-L shell after the magnetospheric compressions, and their loss is associated with the intense plasmaspheric hiss, electromagnetic ion cyclotron (EMIC) waves, relativistic electron precipitation (observed by POES/NOAA satellites at 850 km), and magnetic field fluctuations in the Pc5 band. Finally, the intense EMIC waves and whistler mode hiss jointly cause the rapidly pitch angle scattering loss of the relativistic electrons within 10 h. Moreover, the Pc5 ULF waves also lead to the slowly outward radial diffusion of the relativistic electrons in the high-L region with a negative electron phase space density gradient.

  13. Combined Global MHD and Test-Particle Simulation of a Radiation Belt Storm: Comparing Depletion, Recovery and Enhancement with in Situ Measurements

    Science.gov (United States)

    Sorathia, K.; Ukhorskiy, A. Y.; Merkin, V. G.; Wiltberger, M. J.; Lyon, J.; Claudepierre, S. G.; Fennell, J. F.

    2017-12-01

    During geomagnetic storms the intensities of radiation belt electrons exhibit dramatic variability. In the main phase electron intensities exhibit deep depletion over a broad region of the outer belt. The intensities then increase during the recovery phase, often to levels that significantly exceed their pre-storm values. In this study we analyze the depletion, recovery and enhancement of radiation belt intensities during the 2013 St. Patrick's geomagnetic storm. We simulate the dynamics of high-energy electrons using our newly-developed test-particle radiation belt model (CHIMP) based on a hybrid guiding-center/Lorentz integrator and electromagnetic fields derived from high-resolution global MHD (LFM) simulations. Our approach differs from previous work in that we use MHD flow information to identify and seed test-particles into regions of strong convection in the magnetotail. We address two science questions: 1) what are the relative roles of magnetopause losses, transport-driven atmospheric precipitation, and adiabatic cooling in the radiation belt depletion during the storm main phase? and 2) to what extent can enhanced convection/mesoscale injections account for the radiation belt buildup during the recovery phase? Our analysis is based on long-term model simulation and the comparison of our model results with electron intensity measurements from the MAGEIS experiment of the Van Allen Probes mission.

  14. Wave-Particle Interactions Involving Correlated Electron Bursts and Whistler Chorus in Earth's Radiation Belts

    Science.gov (United States)

    Echterling, N.; Schriver, D.; Roeder, J. L.; Fennell, J. F.

    2017-12-01

    During the recovery phase of substorm plasma injections, the Van Allen Probes commonly observe events of quasi-periodic energetic electron bursts correlating with simultaneously detected upper-band, whistler-mode chorus emissions. These electron bursts exhibit narrow ranges of pitch angles (75-80° and 100-105°) and energies (20-40 keV). Electron cyclotron harmonic (ECH) emissions are also commonly detected, but typically do not display correlation with the electron bursts. To examine sources of free energy and the generation of these wave emissions, an observed electron velocity distribution on January 13, 2013 is used as the starting condition for a particle in cell (PIC) simulation. Effects of temperature anisotropy (perpendicular temperature greater than parallel temperature), the presence of a loss cone and a cold electron population on the generation of whistler and ECH waves are examined to understand wave generation and nonlinear interactions with the particle population. These nonlinear interactions produce energy diffusion along with strong pitch angle scattering into the loss cone on the order of milliseconds, which is faster than a typical bounce period of seconds. To examine the quasi-periodic nature of the electron bursts, a loss-cone recycling technique is implemented to model the effects of the periodic emptying of the loss cone and electron injection on the growth of whistler and ECH waves. The results of the simulations are compared to the Van Allen Probe observations to determine electron acceleration, heating and transport in Earth's radiation belts due to wave-particle interactions.

  15. Observations of energetic helium ions in the Earth's radiation belts during a sequence of geomagnetic storms

    International Nuclear Information System (INIS)

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

    1981-01-01

    Every year a significant number of magnetic storms disturb the earth's magnetosphere and the trapped particle populations. In this paper, we present observations of energetic (MeV) helium ions made with Explorer 45 during a sequence of magnetic storms during June through December of 1972. The first of these storms started on June 17 and had a Dst index excursion to approx.190 gamma, and the MeV helium ions were perturbed primarily beyond 3 earth radii in the equatorial radiation belts with a typical flux increase of an order of magnitude at L = 4. The second storm period took place during August and was associated with very major solar flare activity. Although the Dst extremum was at best 35 gamma less than the June storm, this period can be characterized as irregular (or multi-storm) with strong compression of the magnetosphere and very large (order of magnitude) MeV helium ion flux enhancements down to Lapprox.2. Following this injection the trapped helium ion fluxes showed positive spectral slope with the peak beyond 3.15 MeV at L = 2.5; and at the lowest observable L shells (Lapprox.2--3) little flux decay (tau>100 days) was seen during the rest of the year. Any effects of two subsequent major magnetic storms in September and November were essentially undetectable in the prolonged after-effect of the August solar flare associated MeV helium ion injection. The helium ion radial profile of the phase space density showed a significant negative slope during this period, and we infer that radial diffusion constitutes a significant loss of helium ions on L shells above Lapprox. =4 during the aftermath of the August 1972 magnetic storm

  16. 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.

  17. 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.

  18. Intensity increase of energetic electrons in the outer radiation belt of the Earth in July 1972 according to data of the ''Prognoz-2'' artificial Earth satellite

    International Nuclear Information System (INIS)

    Blyudov, V.A.; Volodichev, N.N.; Nechaev, O.Yu.; Savenko, I.A.; Saraeva, M.A.; Shavrin, P.I.

    1979-01-01

    Carried out is the investigation of the 6-10 MeV electrons in the outer radiation belt of the Earth at the ''Prognoz-2'' artificial Earth satellite along the trajectory of the satellite motion according to the Mac Ilvain parameter L. With the help of a ternary coincidance telescope in Juny 1972, the formationand decay of the belt of energetic electrons with the maximum intensity in the L=3.7 region was recorded. The maximum fluxer of this belt electrons are estimated. It is supposed that the event recorded is the consequence of the magnetospherical disturbance that occured on 18.4.1972

  19. 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.

  20. Analyzing structural variations along strike in a deep-water thrust belt

    Science.gov (United States)

    Totake, Yukitsugu; Butler, Robert W. H.; Bond, Clare E.; Aziz, Aznan

    2018-03-01

    We characterize a deep-water fold-thrust arrays imaged by a high-resolution 3D seismic dataset in the offshore NW Borneo, Malaysia, to understand the kinematics behind spatial arrangement of structural variations throughout the fold-thrust system. The seismic volume used covers two sub-parallel fold trains associated with a series of fore-thrusts and back-thrusts. We measured fault heave, shortening value, fold geometries (forelimb dip, interlimb angle and crest depth) along strike in individual fold trains. Heave plot on strike projection allows to identify individual thrust segments showing semi-elliptical to triangular to bimodal patterns, and linkages of these segments. The linkage sites are marked by local minima in cumulative heave. These local heave minima are compensated by additional structures, such as small imbricate thrusts and tight folds indicated by large forelimb dip and small interlimb angle. Complementary profiles of the shortening amount for the two fold trains result in smoother gradient of total shortening across the structures. We interpret this reflects kinematic interaction between two fold-thrust trains. This type of along-strike variation analysis provides comprehensive understanding of a fold-thrust system and may provide an interpretative strategy for inferring the presence of complex multiple faults in less well-imaged parts of seismic volumes.

  1. Spatial characterization of relativistic electron enhancements in the Earth's outer radiation belt during the Van Allen Probes era

    Science.gov (United States)

    Pinto, V. A.; Bortnik, J.; Moya, P. S.; Lyons, L. R.; Sibeck, D. G.; Kanekal, S. G.

    2017-12-01

    Using Van Allen Probes Relativistic Electron-Proton Telescope (REPT) instrument we have identified 73 relativistic electron enhancement events in the outer radiation belt that occurred at different L values between L = 2.5 and L = 6.0. To determine an enhancement, we have used three different identification methods. We then determine the radial location, MLT location, timing and strength of those enhancements. We discuss the differences of each of the methods and test them to pinpoint the origin and spatial propagation of each enhancement. We have classified the events based on the radial propagation, speed of enhancement and intensity of fluxes and response for energy channels ranging from 1.8 MeV to 6.3 MeV. In addition, we have used OMNI data to study the statistical properties of the solar wind during each event and have classified similarities and differences that might be relevant for each group of enhancements and help us determine the physical process responsible for different types of enhancements. Additionally, we have used >2 MeV electron fluxes at geostationary orbit as measured by the GOES 13 and 15 Energetic Particle Sensor (EPS) instrument to compare our results with the geostationary orbit. Our results suggest that under certain conditions GOES data can be used to predict fluxes at the core of the radiation belt and vice-versa.

  2. 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

  3. 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

  4. Parametric variation of radiated power in Aditya Tokamak

    International Nuclear Information System (INIS)

    Tahiliani, Kumudni; Chowdhuri, M.B.; Manchanda, R.

    2017-01-01

    We report the study of parametric variation of radiated power in Aditya Tokamak for ohmic discharges. The radiated power was measured using AXUV diodes that are responsive to radiation in the range 1 eV to 4 keV and are insensitive to the neutral particles (<0.5 keV). Hence only the radiation power loss is measured and charge exchange losses are excluded. The measured radiated power was also used for the estimation of the effective ion charge, Z eff based on the scaling obtained by the regression analysis of the data from multiple Tokamaks. The estimated values were compared with the experimental Z eff values obtained from the visible continuum measurement. We also tested the scaling for modelled radiation power loss. (author)

  5. Calibration of an electron/proton monitor for the earth's radiation belt at 4 R/sub E/

    International Nuclear Information System (INIS)

    Higbie, P.R.; Belian, R.D.; Argo, H.V.; Baker, D.N.

    1982-03-01

    A charged particle dosimeter (the Burst Detector Dosimeter or BDD) was designed and fabricated and will be flown on certain of the Global Positioning Satellite (GPS) series of spacecraft. The BDD will monitor the dose received by the GPS spacecraft from the fluxes of electrons and protons in the Earth's radiation belt. The BDD uses absorbers in front of silicon sensors to determine the energy thresholds for measuring incident particle fluxes; and the magnitude of energy loss in a single sensor distinguishes between ions and electrons over a wide range of energies. Our electron calibrations were performed to determine accurately the energy response function of the dosimeter. The experimentally determined energy and angular responses are used to determine the equivalent energy thresholds and geometric factors for idealized step function responses

  6. FIREBIRD: A Dual Satellite Mission to Examine the Spatial and Energy Coherence Scales of Radiation Belt Electron Microbursts

    Science.gov (United States)

    Klumpar, D. M.; Spence, H. E.; Larsen, B. A.; Blake, J. B.; Springer, L.; Crew, A. B.; Mosleh, E.; Mashburn, K. W.

    2009-12-01

    FIREBIRD (Focused Investigations of Relativistic Electron Burst Intensity, Range, and Dynamics), a mission under NSF’s “CubeSat-based Science Missions for Space Weather and Atmospheric Research”, will address the broad scientific question: What is the role of microburst electron precipitation in radiation belt dynamics? There are four major candidate processes for losses of relativistic electrons from the outer radiation belt [Millan and Thorne, 2007]: wave-particle interactions with whistler-mode chorus, wave-particle interactions with electromagnetic ion-cyclotron (EMIC) waves, outward radial diffusion to the magnetopause, and loss of adiabaticity on stretched magnetic field lines. FIREBIRD will further investigate the role of whistler-mode chorus, by examining the microburst electron precipitation phenomenon attributed to chorus. Microbursts are thought to be a hallmark of rapid radiation belt losses, possibly removing the entire pre-storm outer zone in a single day [Lorentzen 2001b; O'Brien et al., 2004], yet they are also intimately tied to in-situ acceleration mechanisms. FIREBIRD’s two 1.5U (10 x 10 x 15 cm) CubeSats, each weighing up to 2 kg, will be placed into a common high-inclination bead-on-a-string orbit. The two satellites will remain within ~500 km of one another for six to twelve months, allowing characterization over the spatial scale regime from 10 - 500 km. Each satellite will carry an identical co-aligned pair of solid-state detectors sensitive to electrons from 30 keV to ~3 MeV with 100 msec time resolution. Simultaneous dual measurements provided by the twin FIREBIRD satellites will permit, for the first time, the determination of spatial scales of single microburst events. Along with energy-resolved spectra, these measurements will provide the critically needed answers on the radiation belt loss rate attributed to microbursts. There are three critical questions about relativistic electron microbursts that FIREBIRD can answer: 1) What

  7. Along-dip variations of structural style in the Somali Basin deep-water fold and thrust belt (East Africa)

    Science.gov (United States)

    Cruciani, Francesco; Rinaldo Barchi, Massimiliano

    2014-05-01

    Continental passive margins are place of extended slope-failure phenomena, which can lead to the formation of gravity-driven deep-water fold and thrust belts (DW-FTBs), in regions where no far-field compressional stress is active. These giant geological features, which are confined to the sedimentary section, consist of extensional-compressional linked systems detached over a common décollement, generally salt or shales. The continental passive margin of northern Kenya and southern Somalia is an excellent and relatively unexplored site for recognizing and understanding the DW-FTBs originated over a regional shale décollement. In this study we have interpreted a 2D seismic data-set of the 1980s, hosted by Marine Geoscience Data System at Lamont-Doherty Earth Observatory of Columbia University (http://www.marine-geo.org), and recently reprocessed by ENI, in order to investigate the structural style of a DW-FTB developed offshore of northern Kenya and southern Somalia (Somali Basin). This region records the oldest sedimentary section of the Indian Ocean since the breakup of Gondwana began in the Middle-Lower Jurassic separating Madagascar from Africa. From the Upper Cretaceous to at least the Lower Miocene, the margin has been characterized by gravitational collapse leading to the formation of a DW-FTB extending more than 400 km along-strike. The northern portion of the DW-FTB is about 150 km wide, whilst in the southern portion is few tens of km wide. We analysed the northern portion along a regional seismic section. Our study represents the first detailed structural interpretation of this DW-FTB since its discovery in the 1980s. The good quality of the available reprocessed seismic data has allowed us to identify remarkable along-dip variations in the structural style. The basal detachment constantly deepens landward, in agreement with a prevailing gravity-spreading deformation process (as in the case of the Niger Delta). On the seismic data are not visible, as

  8. Characteristics of Pitch Angle Distributions of 100s Kev Electrons in the Slot Region and Inner Radiation Belt­­­­­­­­

    Science.gov (United States)

    Zhao, H.; Li, X.; Blake, J. B.; Fennell, J.; Claudepierre, S. G.; Baker, D. N.; Jaynes, A. N.; Malaspina, D.

    2014-12-01

    The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-art pitch-angle-resolved data from the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes, a detailed analysis of 100s keV electron PADs below L =4 is performed, in which the PADs is categorized into three types: normal (flux peaking at 90°), cap (exceedingly peaking narrowly around 90°) and 90°-minimum (lower flux at 90°) PADs. By examining the characteristics of the PADs of 460 keV electrons for over a year, we find that the 90°-minimum PADs are generally present in the inner belt (Lpitch angle scattering of hiss waves. Fitting the normal PADs into sinnα form, the parameter n is much higher below L=3 than that in the outer belt and relatively constant in the inner belt but changes significantly in the slot region (2mechanism can hardly explain the formation of 90°-minimum PADs at the center of inner belt. These new and compelling observations, made possible by the high-quality measurements of MagEIS, present a challenge for the wave modelers, and future work is still needed to fully understand them.

  9. Variation of sodium on Mercury with solar radiation pressure

    International Nuclear Information System (INIS)

    Potter, A.E.; Morgan, T.H.

    1987-01-01

    It has been suggested that nonthermal Na atoms with velocities in excess of 2.1 km/sec in the Mercury atmosphere can be accelerated off the planet by solar radiation pressure; Na abundance may accordingly be expected to decrease with increasing radiation pressure. While this is confirmed by the present measurements, high resolution line profile measurements on Na emission indicate that very little, if any, of the Na is nonthermal, while the bulk is at a temperature approaching that of the planetary surface. Attention is given to explanations for the observed variation. 11 references

  10. Direct detection of albedo neutron decay electrons at the inner edge of the radiation belt and experimental determination of neutron density in near-Earth space

    Science.gov (United States)

    Li, X.; Selesnick, R.; Schiller, Q. A.; Zhang, K.; Zhao, H.; Baker, D. N.; Temerin, M. A.

    2017-12-01

    The galaxy is filled with cosmic ray particles, mostly protons with kinetic energy above hundreds of mega-electron volts (MeV). Soon after the discovery of Earth's Van Allen radiation belts almost six decades ago, it was recognized that the main source of inner belt protons, with kinetic energies of tens to hundreds of MeV, is Cosmic Ray Albedo Neutron Decay (CRAND). In this process, cosmic rays reaching the upper atmosphere from throughout the galaxy interact with neutral atoms to produce albedo neutrons which, being unstable to 𝛽 decay, are a potential source of geomagnetically trapped protons and electrons. Protons retain most of the neutrons' kinetic energy while the electrons have lower energies, mostly below 1 MeV. The viability of the electron source was, however, uncertain because measurements showed that electron intensity can vary greatly while the neutron decay rate should be almost constant. Recent measurements from the Relativistic Electron and Proton Telescope integrated little experiment (REPTile) onboard the Colorado Student Space Weather Experiment (CSSWE) CubeSat now show that CRAND is the main electron source for the radiation belt near its inner edge, and also contributes to the inner belt elsewhere. Furthermore, measurement of the CRAND electron intensity provides the first experimental determination of the neutron density in near-Earth space, 2x10-9/cm3, confirming earlier theoretical estimates.

  11. Van Allen Probes Science Gateway: Single-Point Access to Long-Term Radiation Belt Measurements and Space Weather Nowcasting

    Science.gov (United States)

    Romeo, G.; Barnes, R. J.; Ukhorskiy, A. Y.; Sotirelis, T.; Stephens, G.

    2017-12-01

    The Science Gateway gives single-point access to over 4.5 years of comprehensive wave and particle measurements from the Van Allen Probes NASA twin-spacecraft mission. The Gateway provides a set of visualization and data analysis tools including: HTML5-based interactive visualization of high-level data products from all instrument teams in the form of: line plots, orbital content plots, dynamical energy spectra, L-shell context plots (including two-spacecraft plotting), FFT spectra of wave data, solar wind and geomagnetic indices data, etc.; download custom multi-instrument CDF data files of selected data products; publication quality plots of digital data; combined orbit predicts for mission planning and coordination including: Van Allen Probes, MMS, THEMIS, Arase (ERG), Cluster, GOES, Geotail, FIREBIRD; magnetic footpoint calculator for coordination with LEO and ground-based assets; real-time computation and processing of empirical magnetic field models - computation of magnetic ephemeris, computation of adiabatic invariants. Van Allen Probes is the first spacecraft mission to provide a nowcast of the radiation environment in the heart of the radiation belts, where the radiation levels are the highest and most dangerous for spacecraft operations. For this purpose, all instruments continuously broadcast a subset of their science data in real time. Van Allen Probes partners with four foreign institutions who operate ground stations that receive the broadcast: Korea (KASI), the Czech republic (CAS), Argentina (CONAE), and Brazil (INPE). The SpWx broadcast is then collected at APL and delivered to the community via the Science Gateway.

  12. A new high background radiation area in the Geothermal region of Eastern Ghats Mobile Belt (EGMB) of Orissa, India

    International Nuclear Information System (INIS)

    Baranwal, V.C.; Sharma, S.P.; Sengupta, D.; Sandilya, M.K.; Bhaumik, B.K.; Guin, R.; Saha, S.K.

    2006-01-01

    A high natural radiation zone is investigated for the first time in a geothermal region of Eastern Ghats Mobile Belt (EGMB) of Orissa state in India. The surrounding area comprises a geothermal region which has surveyed using a portable pulsed Geiger-Muller counter. On the basis of findings of GM counter, an area was marked as a high radiation zone. Soil and rock samples collected from the high radiation zone were analyzed by γ-ray spectrometry (GRS) using NaI(Tl) detector. The radioactivity is found to be contributed mainly by thorium. Concentration of thorium is reported to be very high compared to their normal abundance in crustal rocks. Further, concentrations of 238 U and 40 K are also high compared to normal abundance in crustal rocks but their magnitude is comparatively less than that of thorium. The average concentrations of 238 U (i.e. U(β-γ)), 232 Th and 40 K are found to be 33, 459ppm and 3%, respectively, in soils and 312, 1723ppm and 5%, respectively, in the granitic rocks. Maximum concentrations of 238 U, 232 Th and 40 K are found to be 95, 1194ppm and 4%, respectively, in soils and 1434, 10,590ppm and 8%, respectively, in the granitic rocks. Radioactive element emits various energies in its decay chain. High energies are utilized to estimate the concentration of actual 238 U, 232 Th and 40 K using a NaI(Tl) detector, however, low energies are used for the same in an HPGe detector. Some of the rock samples (eight in number) were also analyzed using HPGe detector for studying the behavior of low energies emitted in the decay series of uranium and thorium. The absorbed gamma dose rate in air and external annual dose rate of the high radiation zone are calculated to be 2431nGy/h and 3.0mSv/y, respectively. It is approximately 10 times greater than the dose rates obtained outside the high radiation zone. The high concentration of uranium and thorium may be one of the possible heat sources together with the normal geothermal gradient for hot springs

  13. 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)

    Choi, C.-R.; Dokgo, K.; Min, K.-W.; Woo, M.-H.; Choi, E.-J.; Hwang, J.; Park, Y.-D.; Lee, D.-Y.

    2015-01-01

    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

  14. A revised model of Jupiter's inner electron belts: Updating the Divine radiation model

    Science.gov (United States)

    Garrett, Henry B.; Levin, Steven M.; Bolton, Scott J.; Evans, Robin W.; Bhattacharya, Bidushi

    2005-02-01

    In 1983, Divine presented a comprehensive model of the Jovian charged particle environment that has long served as a reference for missions to Jupiter. However, in situ observations by Galileo and synchrotron observations from Earth indicate the need to update the model in the inner radiation zone. Specifically, a review of the model for 1 MeV data. Further modifications incorporating observations from the Galileo and Cassini spacecraft will be reported in the future.

  15. Ducting of the Whistler-Mode Waves by Magnetic Field-Aligned Density Enhancements in the Radiation Belt

    Science.gov (United States)

    Streltsov, A. V.; Bengtson, M.; English, D.; Miller, M.; Turco, L.

    2017-12-01

    Whistler-mode waves (or whistlers) are the right-hand polarized electromagnetic waves with a frequency in the range above the lower hybrid frequency and below the electron cyclotron frequency. They can efficiently interact with energetic electrons in the equatorial magnetosphere and remediate them from the earth's radiation belt. These interactions are non-linear, they depend on the wave amplitude, and for them to be efficient the wave power needs to be delivered from the transmitter to the interaction region without significant losses. The main physical mechanism which can solve this problem is ducting/guiding of whistlers by magnetic field-aligned density inhomogeneities or ducts. We present results from a modeling of whistler-mode waves observed by the NASA Van Allen Probes satellites inside the ducts formed by density enhancements (also known as, high-density ducts or HDD). Our previous studies suggest that HDD can confine without leakage only waves with some particular parameters (frequency, perpendicular and parallel wavelength) connected with the parameters of the duct (like duct's "width" and "depth"). Our numerical results confirm that 1) the high-density ducts with amplitudes and perpendicular sizes observed by the RBSP satellites can indeed guide whistlers over significant distances along the ambient magnetic field with small leakage, and 2) the quality of the ducting indeed depends on the wave perpendicular and parallel wavelengths and, therefore, the fact that the wave is ducted by HDD can be used to determine parameters of the wave.

  16. A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region

    International Nuclear Information System (INIS)

    Yang, Chang; Su, Z.; Xiao, F.; Zheng, H.

    2017-01-01

    Energetic (hundreds of keV) electrons in the radiation belt slot region have been found to exhibit the butterfly pitch angle distributions. Resonant interactions with magnetosonic and whistler-mode waves are two potential mechanisms for the formation of these peculiar distributions. Here we perform a statistical study of energetic electron pitch angle distribution characteristics measured by Van Allen Probes in the slot region during a three-year period from May 2013 to May 2016. Our results show that electron butterfly distributions are closely related to magnetosonic waves rather than to whistlermode waves. Both electron butterfly distributions and magnetosonic waves occur more frequently at the geomagnetically active times than at the quiet times. In a statistical sense, more distinct butterfly distributions usually correspond to magnetosonic waves with larger amplitudes and vice versa. The averaged magnetosonic wave amplitude is less than 5 pT in the case of normal and flat-top distributions with a butterfly index BI = 1 but reaches ~ 35–95 pT in the case of distinct butterfly distributions with BI > 1:3. For magnetosonic waves with amplitudes > 50 pT, the occurrence rate of butterfly distribution is above 80%. Our study suggests that energetic electron butterfly distributions in the slot region are primarily caused by magnetosonic waves.

  17. Generation of Nonlinear Electric Field Bursts in the Outer Radiation Belt through Electrons Trapping by Oblique Whistler Waves

    Science.gov (United States)

    Agapitov, Oleksiy; Drake, James; Mozer, Forrest

    2016-04-01

    Huge numbers of different nonlinear structures (double layers, electron holes, non-linear whistlers, etc. referred to as Time Domain Structures - TDS) have been observed by the electric field experiment on board the Van Allen Probes. A large part of the observed non-linear structures are associated with whistler waves and some of them can be directly driven by whistlers. The parameters favorable for the generation of TDS were studied experimentally as well as making use of 2-D particle-in-cell (PIC) simulations for the system with inhomogeneous magnetic field. It is shown that an outward propagating front of whistlers and hot electrons amplifies oblique whistlers which collapse into regions of intense parallel electric field with properties consistent with recent observations of TDS from the Van Allen Probe satellites. Oblique whistlers seed the parallel electric fields that are driven by the beams. The resulting parallel electric fields trap and heat the precipitating electrons. These electrons drive spikes of intense parallel electric field with characteristics similar to the TDSs seen in the VAP data. The decoupling of the whistler wave and the nonlinear electrostatic component is shown in PIC simulation in the inhomogeneous magnetic field system. These effects are observed by the Van Allen Probes in the radiation belts. The precipitating hot electrons propagate away from the source region in intense bunches rather than as a smooth flux.

  18. Thermal electron acceleration by electric field spikes in the outer radiation belt: generation of field-aligned pitch angle distributions

    Science.gov (United States)

    Vasko, I.; Agapitov, O. V.; Mozer, F.; Artemyev, A.

    2015-12-01

    Van Allen Probes observations in the outer radiation belt have demonstrated an abundance non-linear electrostatic stucture called Time Domain Structures (TDS). One of the type of TDS is electrostatic electron-acoustic double layers (DL). Observed DLs are frequently accompanied by field-aligned (bi-directional) pitch angle distributions (PAD) of electrons with energies from hundred eVs up to several keV (rarely up to tens of keV). We perform numerical simulations of the DL interaction with thermal electrons making use of the test particle approach. DL parameters assumed in the simulations are adopted from observations. We show that DLs accelerate thermal electrons parallel to the magnetic field via the electrostatic Fermi mechanism, i.e. due to reflections from DL potential humps. Due to this interaction some fraction of electrons is scattered into the loss cone. The electron energy gain is larger for larger DL scalar potential amplitudes and higher propagation velocities. In addition to the Fermi mechanism electrons can be trapped by DLs in their generation region and accelerated due to transport to higher latitudes. Both mechanisms result in formation of field-aligned PADs for electrons with energies comparable to those found in observations. The Fermi mechanism provides field-aligned PADs for <1 keV electrons, while the trapping mechanism extends field-aligned PADs to higher energy electrons.

  19. Reproducing the observed energy-dependent structure of Earth's electron radiation belts during storm recovery with an event-specific diffusion model

    Czech Academy of Sciences Publication Activity Database

    Ripoll, J.-F.; Reeves, G. D.; Cunningham, G. S.; Loridan, V.; Denton, M.; Santolík, Ondřej; Kurth, W. S.; Kletzing, C. A.; Turner, D. L.; Henderson, M. G.; Ukhorskiy, A. Y.

    2016-01-01

    Roč. 43, č. 11 (2016), s. 5616-5625 ISSN 0094-8276 R&D Projects: GA MŠk(CZ) LH15304 Institutional support: RVO:68378289 Keywords : radiation belts * slot region * electron losses * wave particle interactions * hiss wave s * electron lifetimes Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.253, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2016GL068869/full

  20. Empirical model of the high-latitude boundary of the Earth's outer radiation belt at altitudes of up to 1000 km

    Science.gov (United States)

    Kalegaev, V. V.; Barinova, W. O.; Myagkova, I. N.; Eremeev, V. E.; Parunakyan, D. A.; Nguyen, M. D.; Barinov, O. G.

    2018-01-01

    An empirical model of the high-latitude boundary of the outer Earth's radiation belt (ERB) has been presented, which is based on the measurement data of electron fluxes on the polar low-orbit CORONAS-Photon, Meteor-M1, and Meteor-M2 satellites. The boundary was determined by a sharp decrease to the background level of the flux of trapped electrons with energies of 100 or 200 keV in the polar part of the profile of the outer radiation belt. A numerical algorithm has been implemented to determine the time moment, when the fastest flux changes are recorded. The primary search was carried out, first, on 30 s averaged data, then repeated on data with a higher resolution. A functional dependence was obtained in order to approximate the obtained set of intersections of the boundary by elliptical curve. The empirical model constructed using the CORONAS-Photon measurement data in the epoch of anomalously low geomagnetic activity reflects the longitude structure of the high-latitude boundary of the outer radiation belt associated with the internal Earth's magnetic field (MF), as well as its dependence on the universal time. Based on the data of intersections of the high-latitude boundary of the outer ERB (OERB) in the epoch of 2014-2016, the latitudinal shift of the boundary to the equator dependent on geomagnetic activity has been determined, as well as the nightside shift of the boundary due to the diurnal rotation of the Earth.

  1. High-altitude cosmic ray neutrons: probable source for the high-energy protons of the earth's radiation belts

    International Nuclear Information System (INIS)

    Hajnal, F.; Wilson, J.

    1992-01-01

    'Full Text:' Several High-altitude cosmic-ray neutron measurements were performed by the NASA Ames Laboratory in the mid-to late-1970s using airplanes flying at about 13km altitude along constant geomagnetic latitudes of 20, 44 and 51 degrees north. Bonner spheres and manganese, gold and aluminium foils were used in the measurements. In addition, large moderated BF-3 counters served as normalizing instruments. Data analyses performed at that time did not provide complete and unambiguous spectral information and field intensities. Recently, using our new unfolding methods and codes, and Bonner-sphere response function extensions for higher energies, 'new' neutron spectral intensities were obtained, which show progressive hardening of neutron spectra as a function of increasing geomagnetic latitude, with substantial increases in the energy region iron, 1 0 MeV to 10 GeV. For example, we found that the total neutron fluences at 20 and 51 degrees magnetic north are in the ratio of 1 to 5.2 and the 10 MeV to 10 GeV fluence ratio is 1 to 18. The magnitude of these ratios is quite remarkable. From the new results, the derived absolute neutron energy distribution is of the correct strength and shape for the albedo neutrons to be the main source of the high-energy protons trapped in the Earth's inner radiation belt. In addition, the results, depending on the extrapolation scheme used, indicate that the neutron dose equivalent rate may be as high as 0.1 mSv/h near the geomagnetic north pole and thus a significant contributor to the radiation exposures of pilots, flight attendants and the general public. (author)

  2. Variation of Neutron Moderating Power on HDPE by Gamma Radiation

    International Nuclear Information System (INIS)

    Park, Kwang June; Ju, June Sik; Kang, Hee Young; Shin, Hee Sung; Kim, Ho Dong

    2009-01-01

    High density polyethylene (HDPE) is degraded due to a radiation-induced oxidation when it is used as a neutron moderator in a neutron counter for a nuclear material accounting of spent fuels. The HDPE exposed to the gamma-ray emitted from the fission products in a spent nuclear fuel results in a radiation-induced degradation which changes its original molecular structure to others. So a neutron moderating power variation of HDPE, irradiated by a gamma radiation, was investigated in this work. Five HDPE moderator structures were exposed to the gamma radiation emitted from a 60 Co source to a level of 10 5 -10 9 rad to compare their post-irradiation properties. As a result of the neutron measurement test with 5 irradiated HDPE structures and a neutron measuring system, it was confirmed that the neutron moderating power for the 105 rad irradiated HDPE moderator revealed the largest decrease when the un-irradiated pure one was used as a reference. It implies that a neutron moderating power variation of HDPE is not directly proportional to the integrated gamma dose rate. To clarify the cause of these changes, some techniques such as a FTIR, an element analysis and a densitometry were employed. As a result of these analyses, it was confirmed that the molecular structure of the gamma irradiated HDPEs had partially changed to others, and the contents of hydrogen and oxygen had varied during the process of a radiation-induced degradation. The mechanism of these changes cannot be explained in detail at present, and thus need further study

  3. 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.

  4. Assessment of Radiation Background Variation for Moving Detection Systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, James Christopher [Los Alamos National Laboratory; Rennie, John Alan [Los Alamos National Laboratory; Toevs, James Waldo [Los Alamos National Laboratory; Wallace, Darrin J. [Los Alamos National Laboratory; Abhold, Mark Edward [Los Alamos National Laboratory

    2015-07-13

    The introduction points out that radiation backgrounds fluctuate across very short distances: factors include geology, soil composition, altitude, building structures, topography, and other manmade structures; and asphalt and concrete can vary significantly over short distances. Brief descriptions are given of the detection system, experimental setup, and background variation measurements. It is concluded that positive and negative gradients can greatly reduce the detection sensitivity of an MDS: negative gradients create opportunities for false negatives (nondetection), and positive gradients create a potentially unacceptable FAR (above 1%); the location of use for mobile detection is important to understand; spectroscopic systems provide more information for screening out false alarms and may be preferred for mobile use; and mobile monitor testing at LANL accounts for expected variations in the background.

  5. Along-strike structural variation and thermokinematic development of the Cenozoic Bitlis-Zagros fold-thrust belt, Turkey and Iraqi Kurdistan

    Science.gov (United States)

    Barber, Douglas E.; Stockli, Daniel F.; Koshnaw, Renas I.; Tamar-Agha, Mazin Y.; Yilmaz, Ismail O.

    2016-04-01

    The Bitlis-Zagros orogen in northern Iraq is a principal element of the Arabia-Eurasia continent collision and is characterized by the lateral intersection of two structural domains: the NW-SE trending Zagros proper system of Iran and the E-W trending Bitlis fold-thrust belt of Turkey and Syria. While these components in northern Iraq share a similar stratigraphic framework, they exhibit along-strike variations in the width and style of tectonic zones, fold morphology and trends, and structural inheritance. However, the distinctions of the Bitlis and Zagros segments remains poorly understood in terms of timing and deformation kinematics as well as first-order controls on fold-thrust development. Structural and stratigraphic study and seismic data combined with low-T thermochronometry provide the basis for reconstructions of the Bitlis-Zagros fold-thrust belt in southeastern Turkey and northern Iraq to elucidate the kinematic and temporal relationship of these two systems. Balanced cross-sections were constructed and incrementally restored to quantify the deformational evolution and use as input for thermokinematic models (FETKIN) to generate thermochronometric ages along the topographic surface of each cross-section line. The forward modeled thermochronometric ages from were then compared to new and previously published apatite and zircon (U-Th)/He and fission-track ages from southeastern Turkey and northern Iraq to test the validity of the timing, rate, and fault-motion geometry associated with each reconstruction. The results of these balanced theromokinematic restorations integrated with constraints from syn-tectonic sedimentation suggest that the Zagros belt between Erbil and Suleimaniyah was affected by an initial phase of Late Cretaceous exhumation related to the Proto-Zagros collision. During the main Zagros phase, deformation advanced rapidly and in-sequence from the Main Zagros Fault to the thin-skinned frontal thrusts (Kirkuk, Shakal, Qamar) from middle

  6. Detection of Chorus Elements and other Wave Signatures Using Geometric Computational Techniques in the Van Allen radiation belts

    Science.gov (United States)

    Sengupta, A.; Kletzing, C.; Howk, R.; Kurth, W. S.

    2017-12-01

    An important goal of the Van Allen Probes mission is to understand wave particle interactions that can energize relativistic electron in the Earth's Van Allen radiation belts. The EMFISIS instrumentation suite provides measurements of wave electric and magnetic fields of wave features such as chorus that participate in these interactions. Geometric signal processing discovers structural relationships, e.g. connectivity across ridge-like features in chorus elements to reveal properties such as dominant angles of the element (frequency sweep rate) and integrated power along the a given chorus element. These techniques disambiguate these wave features against background hiss-like chorus. This enables autonomous discovery of chorus elements across the large volumes of EMFISIS data. At the scale of individual or overlapping chorus elements, topological pattern recognition techniques enable interpretation of chorus microstructure by discovering connectivity and other geometric features within the wave signature of a single chorus element or between overlapping chorus elements. Thus chorus wave features can be quantified and studied at multiple scales of spectral geometry using geometric signal processing techniques. We present recently developed computational techniques that exploit spectral geometry of chorus elements and whistlers to enable large-scale automated discovery, detection and statistical analysis of these events over EMFISIS data. Specifically, we present different case studies across a diverse portfolio of chorus elements and discuss the performance of our algorithms regarding precision of detection as well as interpretation of chorus microstructure. We also provide large-scale statistical analysis on the distribution of dominant sweep rates and other properties of the detected chorus elements.

  7. Energetic electrons at Uranus: Bimodal diffusion in a satellite limited radiation belt

    International Nuclear Information System (INIS)

    Selesnick, R.S.; Stone, E.C.

    1991-01-01

    The Voyager 2 cosmic ray experiment observed intense electron fluxes in the middle magnetosphere of Uranus. High counting rates in several of the solid-state detectors precluded in the normal multiple coincidence analysis used for cosmic ray observations, and the authors have therefore performed laboratory measurements of the single-detector response to electrons. These calibrations allow a deconvolution from the counting rate data of the electron energy spectrum between energies of about 0.7 and 2.5 MeV. They present model fits to the differential intensity spectra from observations between L values of 6 and 15. The spectra are well represented by power laws in kinetic energy with spectral indices between 5 and 7. The phase space density at fixed values of the first two adiabatic invariants generally increases with L, indicative of an external source. However, there are also local minima associated with the satellites Ariel and Umbriel, indicating either a local source or an effective source due to nonconservation of the first two adiabatic invariants. For electrons which mirror at the highest magnetic latitudes, the local minimum associated with Ariel is radically displaced from the minimum L of that satellite by ∼0.5. The latitude variation of the satellite absorption efficiency predicts that if satellite losses are replenished primarily by radial diffusion there should be an increasing pitch angle anisotropy with decreasing L. The uniformity in the observed anisotropy outside the absorption regions then suggests that it is maintained by pitch angle diffusion. The effective source due to pitch angle diffusion is insufficient to cause the phase space density minimum associated with Ariel. Model solutions of the simultaneous radial and pitch angle diffusion equation show that the displacement of the high-latitude Ariel signature is also consistent with a larger effective source

  8. Variation in radiation doses in paediatric cardiac catheterisation procedures

    International Nuclear Information System (INIS)

    Al-Haj, A. N.; Lobriguito, A. M.; Rafeh, W.

    2008-01-01

    Paediatric cardiac catheterisation involves diagnostic and therapeutic procedures that range from simple to complex and can subject paediatric patients to varying radiation doses. The study aims to determine the variation in entrance doses in patients in terms of dose-area product (DAP) values and to investigate the methods for optimising radiation protection. A total of 190 paediatric patients belonging to age groups 0, 1, 5 and 10 y who underwent diagnostic and six selected therapeutic procedures at King Faisal Specialist Hospital and Research Centre, Riyadh (Saudi Arabia) were included in the study. Therapeutic procedures include coarctation (COA), patent ductus arteriosus (PDA), radiofrequency ablation, pulmonary, embolisation and septostomy. Fluoroscopy and cine radiography were used in all procedures. Patient demography (weight, age, gender and height), radiographic technique factors, fluoroscopy and cine time, frame rate, and DAP values were taken from patients records. Effective doses for each procedure were estimated from the DAP values. The mean DAP per procedure were analysed for correlation with patient equivalent cylindrical diameter, weight, fluoroscopy time and number of frames. Factors influencing the variation in doses were investigated. Initial results show that PDA occlusion has the highest mean DAP value of 23.21 Gy-cm 2 , while the diagnostic and septostomy procedures have the lowest value of 7.77 and 6.95 Gy-cm 2 , respectively. (authors)

  9. Analysis of the temporal variation of radiation balance components in arid rice (Oryza sativa L.) culture

    International Nuclear Information System (INIS)

    Prates, J.E.; Coelho, D.T.; Steinmetz, S.

    1988-01-01

    The time variation of measured radiation balance components in a cultived rice area (Oryza sativa L.) under arid conditions in the Brazil central-west region was analysed. The relation between global solar radiation, radiation balance, reflected radiation and terrestrial effective radiation in three different stages of the culture development: vegetative stage; blooming and maturation, was determined. (M.C.K.) [pt

  10. Spectral variation of the solar radiation during an eclipse

    Directory of Open Access Journals (Sweden)

    Peter Koepke

    2001-05-01

    Full Text Available The time dependent variation of the spectral extraterrestrial solar flux is modelled for the conditions during a total eclipse. These data are used to calculate irradiance and actinic flux at the Earth’s surface for atmospheric conditions of August 11, 1999 at Weihenstephan. These results are compared with measurements. It is shown, that the spectral composition of solar radiation varies during the eclipse, since solar limb darkening has a spectral dependence. The solar radiation differs from that of a hypothetical sun without limb darkening by up to 30% in the near IR at 1500 nm and 60% in the UV-B at 310 nm. As shown by a comparison of modelling and measurements, this spectral variation has to be taken into account for modelling of UV radiative quantities in the atmosphere and resulting photochemical processes. The effect of broken cloudiness on irradiance and actinic flux and its dependency on wavelength and receiver geometry is explained. Der Verlauf der spektralen extraterrestrischen solaren Strahlung wÄhrend einer Sonnenfinsternis wurde berechnet. Basierend auf diesen Daten, unter BerÜcksichtigung der atmosphÄrischen Bedingungen am 11. August 1999 in Weihenstephan, wurden Globalstrahlung und Aktinischer Fluss am Boden modelliert und mit Messwerten verglichen. Die spektrale Zusammensetzung der Strahlung Ändert sich wÄhrend einer Sonnenfinsternis, bedingt durch die wellenlÄngenabhÄngige Randverdunklung der Sonne. Im Vergleich zu einer hypothetischen Sonne ohne Randverdunklung ist die solare Strahlung im nahen IR um bis zu 30% gemindert und im UVB bei 310 nm um bis zu 60%. Diese spektralen Änderungen sollten bei der Modellierung von Strahlung, z.B. fÜr photochemische Prozesse berÜcksichtigt werden. Dies wurde durch Messung und Modellierung gezeigt. Der Einfluss von Wolken auf gemessene Werte von Globalstrahlung und Aktinischem Fluss wurde untersucht und erklÄrt.

  11. Mapping lightning discharges on Earth with lightning-generated whistlers wave emission in space and their effects on radiation belt electrons

    Science.gov (United States)

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

    2017-12-01

    It is widely accepted that the slot region of the Van Allen radiation belts is sculpted by the presence of whistler mode waves especially by plasmaspheric hiss emissions. In this work, we investigate the role of lightning-generated whistler waves (LGW), which also contribute to scatter electrons trapped in the plasmaphere but, in general, to a lesser extent due to their low mean amplitude and occurrence rate. Our goal is to revisit the characterization of LGW occurrence in the Earth's atmosphere and in space as well as the computation of LGW effects by looking at a series of particular events, among which intense events, in order to characterize maximal scattering effects. We use multicomponent measurements of whistler mode waves by the Waves instrument of Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes spacecraft as our primary data source. We combine this data set with local measurements of the plasma density. We also use the data of the World Wide Lightning Location Network in order to localize the source of lightning discharges on Earth and their radiated energy, both locally at the footprint of the spacecraft and, globally, along the drift path. We discuss how to relate the signal measured in space with the estimation of the power emitted in the atmosphere and the associated complexity. Using these unique data sets we model the coefficients of quasi-linear pitch angle diffusion and we estimate effects of these waves on radiation belt electrons. We show evidence that lightning generated whistlers can, at least in some cases, influence the radiation belt dynamics.

  12. Separation of the Galactic Cosmic Rays and Inner Earth Radiation Belt Contributions to the Daily Dose Onboard the International Space Station in 2005-2011

    Science.gov (United States)

    Lishnevskii, A. E.; Benghin, V. V.

    2018-03-01

    The DB-8 detectors of the ISS radiation monitoring system (RMS) have operated almost continuously onboard the ISS service module since August 2001 till December 2014. The RMS data obtained were used for the daily monitoring of the radiation environment aboard the station. This paper considers the technique of RMS data analysis that allows one to distinguish the contributions of galactic cosmic rays and the Earth's inner radiation belt to the daily dose based on the dosimetry data obtained as a result of the station's passage in areas of the highest geomagnetic latitudes. The paper presents the results of an analysis of the dosimetry data based on this technique for 2005-2011, as well as a comparison with similar results the authors obtained previously using the technique based on an analysis of the dosimetry data obtained during station passages in the area of the South Atlantic Anomaly.

  13. Van Allen Probe Observations of Chorus Wave Activity, Source and Seed electrons, and the Radiation Belt Response During ICME and CIR Storms

    Science.gov (United States)

    Bingham, S.; Mouikis, C.; Kistler, L. M.; Farrugia, C. J.; Paulson, K. W.; Huang, C. L.; Boyd, A. J.; Spence, H. E.; Kletzing, C.

    2017-12-01

    Whistler mode chorus waves are electromagnetic waves that have been shown to be a major contributor to enhancements in the outer radiation belt during geomagnetic storms. The temperature anisotropy of source electrons (10s of keV) provides the free energy for chorus waves, which can accelerate sub-relativistic seed electrons (100s of keV) to relativistic energies. This study uses Van Allen Probe observations to examine the excitation and plasma conditions associated with chorus wave observations, the development of the seed population, and the outer radiation belt response in the inner magnetosphere, for 25 ICME and 35 CIR storms. Plasma data from the Helium Oxygen Proton Electron (HOPE) instrument and magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) are used to identify chorus wave activity and to model a linear theory based proxy for chorus wave growth. A superposed epoch analysis shows a peak of chorus wave power on the dawnside during the storm main phase that spreads towards noon during the storm recovery phase. According to the linear theory results, this wave activity is driven by the enhanced convection driving plasma sheet electrons across the dayside. Both ICME and CIR storms show comparable levels of wave growth. Plasma data from the Magnetic Electron Ion Spectrometer (MagEIS) and the Relativistic Electron Proton Telescope (REPT) are used to observe the seed and relativistic electrons. A superposed epoch analysis of seed and relativistic electrons vs. L shows radiation belt enhancements with much greater frequency in the ICME storms, coinciding with a much stronger and earlier seed electron enhancement in the ICME storms.

  14. 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

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

    International Nuclear Information System (INIS)

    Koller, Josep; Reeves, Geoffrey D.; Friedel, Reiner H.W.

    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 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 physical

  16. Interaction of ring current and radiation belt protons with ducted plasmaspheric hiss. 2. Time evolution of the distribution function

    Science.gov (United States)

    Kozyra, J. U.; Rasmussen, C. E.; Miller, R. H.; Villalon, E.

    1995-11-01

    The evolution of the bounce-averaged ring current/radiation belt proton distribution is simulated during resonant interactions with ducted plasmaspheric hiss. The plasmaspheric hiss is assumed to be generated by ring current electrons and to be damped by the energetic protons. Thus energy is transferred between energetic electrons and protons using the plasmaspheric hiss as a mediary. The problem is not solved self-consistently. During the simulation period, interactions with ring current electrons (not represented in the model) are assumed to maintain the wave amplitudes in the presence of damping by the energetic protons, allowing the wave spectrum to be held fixed. Diffusion coefficients in pitch angle, cross pitch angle/energy, and energy were previously calculated by Kozyra et al. (1994) and are adopted for the present study. The simulation treats the energy range, E>=80 keV, within which the wave diffusion operates on a shorter timescale than other proton loss processes (i.e., Coulomb drag and charge exchange). These other loss processes are not included in the simulation. An interesting result of the simulation is that energy diffusion maximizes at moderate pitch angles near the edge of the atmospheric loss cone. Over the simulation period, diffusion in energy creates an order of magnitude enhancement in the bounce-averaged proton distribution function at moderate pitch angles. The loss cone is nearly empty because scattering of particles at small pitch angles is weak. The bounce-averaged flux distribution, mapped to ionospheric heights, results in elevated locally mirroring proton fluxes. OGO 5 observed order of magnitude enhancements in locally mirroring energetic protons at altitudes between 350 and 1300 km and invariant latitudes between 50° and 60° (Lundblad and Soraas, 1978). The proton distributions were highly anisotropic in pitch angle with nearly empty loss cones. The similarity between the observed distributions and those resulting from this

  17. Late Early-Cretaceous quartz diorite-granodiorite-monzogranite association from the Gaoligong belt, southeastern Tibet Plateau: Chemical variations and geodynamic implications

    Science.gov (United States)

    Zhu, Ren-Zhi; Lai, Shao-Cong; Qin, Jiang-Feng; Zhao, Shao-Wei; Wang, Jiang-Bo

    2017-09-01

    Geochemical variations in granitic rocks may be controlled by their source rocks, melting reactions and subsequent magmatic processes, which resulted from various geodynamic processes related to subduction, collision, or slab break-off. Here we report new LA-ICP-MS zircon U-Pb ages and Hf isotopes, whole-rock chemistry and Sr-Nd isotopes for the late Early Cretaceous quartz diorite, granodiorite and monzogranite in the Gaoligong belt, southeastern Tibet Plateau. The zircon U-Pb dating yield ages of 113.9 ± 1.6, 111.7 ± 0.8, and 112.8 ± 1.7 Ma for the quartz diorite, granodiorite, and monzogranite, respectively, which are coeval with bimodal magmatism in the central and northern Lhasa sub-terrane. There are the distinct sources regions for the quartz diorite and granodiorite-monzogranite association. The quartz diorites are sodic, calc-alkaline and have high Mg# (52-54) values. They also have elevated initial 87Sr/86Sr (0.707019 to 0.709176) and low εNd(t) (- 5.16 to - 7.63), with variable zircon εHf(t) values (+ 5.65 to - 9.02). Zircon chemical data indicate a typical crustal-derived character with high Th (142-1260 ppm) and U (106-1082 ppm) and moderate U/Yb ratios (0.30 to 2.32) and Y content (705-1888 ppm). Those data suggest that the quartz diorites were derived from partial melting of ancient basaltic lower crust by a mantle-derived magma in source region. The granodiorite-monzogranite association has high-K calc-alkaline, weakly peraluminous characters. They show lower Nb/Ta (5.57 to 13.8), CaO/Na2O (0.62 to 1.21), higher Al2O3/TiO2 (24.4 to 44.4) ratios, more evolved whole-rock Sr-Nd and zircon Hf isotopic signatures, all of which suggest derivation from mixed basaltic and metasedimentary source rocks in a deep crustal zone. We propose that the granitic magmatisms at ca. 113-110 Ma in the Gaologong belt was triggered by the slab break-off of Bangong-Nujiang Tethyan oceanic lithosphere. Supplementary Dataset Table 2. Single-grain zircon Hf isotopic data

  18. Drift-resonant, relativistic electron acceleration at the outer planets: Insights from the response of Saturn's radiation belts to magnetospheric storms

    Science.gov (United States)

    Roussos, E.; Kollmann, P.; Krupp, N.; Paranicas, C.; Dialynas, K.; Sergis, N.; Mitchell, D. G.; Hamilton, D. C.; Krimigis, S. M.

    2018-05-01

    The short, 7.2-day orbital period of Cassini's Ring Grazing Orbits (RGO) provided an opportunity to monitor how fast the effects of an intense magnetospheric storm-time period (days 336-343/2016) propagated into Saturn's electron radiation belts. Following the storms, Cassini's MIMI/LEMMS instrument detected a transient extension of the electron radiation belts that in subsequent orbits moved towards the inner belts, intensifying them in the process. This intensification was followed by an equally fast decay, possibly due to the rapid absorption of MeV electrons by the planet's main rings. Surprisingly, all this cycle was completed within four RGOs, effectively in less than a month. That is considerably faster than the year-long time scales of Saturn's proton radiation belt evolution. In order to explain this difference, we propose that electron radial transport is partly controlled by the variability of global scale electric fields which have a fixed local time pointing. Such electric fields may distort significantly the orbits of a particular class of energetic electrons that cancel out magnetospheric corotation due to their westward gradient and curvature drifts (termed "corotation-resonant" or "local-time stationary" electrons) and transport them radially between the ring current and the radiation belts within several days and few weeks. The significance of the proposed process is highlighted by the fact that corotation resonance at Saturn occurs for electrons of few hundred keV to several MeV. These are the characteristic energies of seed electrons from the ring current that sustain the radiation belts of the planet. Our model's feasibility is demonstrated through the use of a simple test-particle simulation, where we estimate that uniform but variable electric fields with magnitudes lower that 1.0 mV/m can lead to a very efficient transport of corotation resonant electrons. Such electric fields have been consistently measured in the magnetosphere, and here we

  19. THE HUBBLE WIDE FIELD CAMERA 3 TEST OF SURFACES IN THE OUTER SOLAR SYSTEM: SPECTRAL VARIATION ON KUIPER BELT OBJECTS

    International Nuclear Information System (INIS)

    Fraser, Wesley C.; Brown, Michael E.; Glass, Florian

    2015-01-01

    Here, we present additional photometry of targets observed as part of the Hubble Wide Field Camera 3 (WFC3) Test of Surfaces in the Outer Solar System. Twelve targets were re-observed with the WFC3 in the optical and NIR wavebands designed to complement those used during the first visit. Additionally, all of the observations originally presented by Fraser and Brown were reanalyzed through the same updated photometry pipeline. A re-analysis of the optical and NIR color distribution reveals a bifurcated optical color distribution and only two identifiable spectral classes, each of which occupies a broad range of colors and has correlated optical and NIR colors, in agreement with our previous findings. We report the detection of significant spectral variations on five targets which cannot be attributed to photometry errors, cosmic rays, point-spread function or sensitivity variations, or other image artifacts capable of explaining the magnitude of the variation. The spectrally variable objects are found to have a broad range of dynamical classes and absolute magnitudes, exhibit a broad range of apparent magnitude variations, and are found in both compositional classes. The spectrally variable objects with sufficiently accurate colors for spectral classification maintain their membership, belonging to the same class at both epochs. 2005 TV189 exhibits a sufficiently broad difference in color at the two epochs that span the full range of colors of the neutral class. This strongly argues that the neutral class is one single class with a broad range of colors, rather than the combination of multiple overlapping classes

  20. Two Step Acceleration Process of Electrons in the Outer Van Allen Radiation Belt by Time Domain Electric Field Bursts and Large Amplitude Chorus Waves

    Science.gov (United States)

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

    2014-12-01

    A huge number of different non-linear structures (double layers, electron holes, non-linear whistlers, etc) have been observed by the electric field experiment on the Van Allen Probes in conjunction with relativistic electron acceleration in the Earth's outer radiation belt. These structures, found as short duration (~0.1 msec) quasi-periodic bursts of electric field in the high time resolution electric field waveform, have been called Time Domain Structures (TDS). They can quite effectively interact with radiation belt electrons. Due to the trapping of electrons into these non-linear structures, they are accelerated up to ~10 keV and their pitch angles are changed, especially for low energies (˜1 keV). Large amplitude electric field perturbations cause non-linear resonant trapping of electrons into the effective potential of the TDS and these electrons are then accelerated in the non-homogeneous magnetic field. These locally accelerated electrons create the "seed population" of several keV electrons that can be accelerated by coherent, large amplitude, upper band whistler waves to MeV energies in this two step acceleration process. All the elements of this chain acceleration mechanism have been observed by the Van Allen Probes.

  1. Some features of Jupiter decametric radiation and its temporary variations

    International Nuclear Information System (INIS)

    Levitskij, L.S.

    1977-01-01

    The following parameters of Jupiter decametric radiation are considered: duration of the storms, the distribution of the storms over Jupiter's longitudes and Io's position, the distribution along frequency range, burstness. It is shown that probability W of revealing decametric emission does not depend on solar activity level. The relative probability (W 3 /W) of appearing noise storms of large intensity changes according to variations of solar activity indexes for all frequencies (10-35 MHz). The duration of noise storms, its frequency range, intensity and L-burst number increase systematically with the storm's power. There is a tendency to the expansion of the sources of the emission along the longitude if the observer (the Earth) changes his position from the boundary to center of emission cone. Io effects in decametric emission are appreciable for the largest storms only. For small storms these effects may be revealed only in years of minimum solar activity. A part of storms with large number of L-bursts is correlated with the Asub(p)-index

  2. A mathematical correlation between variations in solar radiation parameters - I: Daily sums of global radiation and midday global radiation

    International Nuclear Information System (INIS)

    Njau, E.C.

    1987-11-01

    An equation that simply relates variations in the daily sums of global radiation and the corresponding midday global radiation data over an arbitrarily chosen location on the Earth is derived from first principles. Although this equation is specifically tailored for periods incorporating only cloudless days, it is modified slightly in order also to suit any period that incorporates either cloudless days or consistently cloudy days or days characterised by consistently distributed cloud patches or any combination of these. Global radiation data for Dar es Salaam, Tanzania, calculated on the basis of the slightly modified version of the equation mentioned above agree with actual measurements to at least 89% if each of the days involved is either fairly cloudless or consistently cloudy or is characterised by fairly consistent cloud patches from sunrise to sunset. This clearly demonstrates that it is quite possible to work out reasonable estimates of the overall global radiation incident on a given area using only the corresponding midday global radiation data for that particular area. (author). 6 refs, 1 fig, 3 tabs

  3. Conveyor belt weigher using a nuclear technique

    International Nuclear Information System (INIS)

    Magal, B.S.

    1976-01-01

    Principles of operation of different types of continuous conveyor belt weighing machines developed for use in factories for bulk weighing of material on conveyor belts without interupting the material flow, are briefly mentioned. The design of nuclear weighing scale making use of the radiation absorption property of the material used is described in detail. The radiation source, choice of the source, detector and geometry of such a weighing scale are discussed. The nucleonic belt weigher is compared with the gravimetric belt weigher system. The advantages of the nuclear system are pointed out. The assembly drawing of the electronics, calibration procedure and performance evaluation are given. (A.K.)

  4. Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)

    Science.gov (United States)

    Kotthoff, Ulrich; Groeneveld, Jeroen; Ash, Jeanine L.; Fanget, Anne-Sophie; Quintana Krupinski, Nadine; Peyron, Odile; Stepanova, Anna; Warnock, Jonathan; Van Helmond, Niels A. G. M.; Passey, Benjamin H.; Rønø Clausen, Ole; Bennike, Ole; Andrén, Elinor; Granoszewski, Wojciech; Andrén, Thomas; Filipsson, Helena L.; Seidenkrantz, Marit-Solveig; Slomp, Caroline P.; Bauersachs, Thorsten

    2017-12-01

    Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past ˜ 8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until ˜ 7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish-marine conditions of the Littorina Sea stage (more saline and warmer) occurred within ˜ 200 years when the connection to the Kattegat became established after ˜ 7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from

  5. Climate variation based on temperature and solar radiation data ...

    African Journals Online (AJOL)

    ckaonga

    2015-03-12

    Mar 12, 2015 ... addition, the concentration of carbon dioxide over Malawi within the same period as temperature and solar radiation data ... plant diseases and pests which may have adverse effects ... object that absorbs and emits radiation).

  6. Resonance zones and quasi-linear diffusion coefficients for radiation belt energetic electron interaction with oblique chorus waves in the Dungey magnetosphere

    International Nuclear Information System (INIS)

    Shi Run; Ni, Binbin; Gu Xudong; Zhao Zhengyu; Zhou Chen

    2012-01-01

    The resonance regions for resonant interactions of radiation belt electrons with obliquely propagating whistler-mode chorus waves are investigated in detail in the Dungey magnetic fields that are parameterized by the intensity of uniform southward interplanetary magnetic field (IMF) Bz or, equivalently, by the values of D=(M/B z,0 ) 1/3 (where M is the magnetic moment of the dipole and B z,0 is the uniform southward IMF normal to the dipole’s equatorial plane). Adoption of background magnetic field model can considerably modify the determination of resonance regions. Compared to the results for the case of D = 50 (very close to the dipole field), the latitudinal coverage of resonance regions for 200 keV electrons interacting with chorus waves tends to become narrower for smaller D-values, regardless of equatorial pitch angle, resonance harmonics, and wave normal angle. In contrast, resonance regions for 1 MeV electrons tend to have very similar spatial lengths along the field line for various Dungey magnetic field models but cover different magnetic field intervals, indicative of a strong dependence on electron energy. For any given magnetic field line, the resonance regions where chorus-electron resonant interactions can take place rely closely on equatorial pitch angle, resonance harmonics, and kinetic energy. The resonance regions tend to cover broader latitudinal ranges for smaller equatorial pitch angles, higher resonance harmonics, and lower electron energies, consistent with the results in Ni and Summers [Phys. Plasmas 17, 042902, 042903 (2010)]. Calculations of quasi-linear bounce-averaged diffusion coefficients for radiation belt electrons due to nightside chorus waves indicate that the resultant scattering rates differ from using different Dungey magnetic field models, demonstrating a strong dependence of wave-induced electron scattering effect on the adoption of magnetic field model. Our results suggest that resonant wave-particle interaction processes

  7. 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)

    West, H.I. Jr.; Buck, R.M.; Davidson, G.

    1979-01-01

    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

  8. Dynamics of the outer radiation belts and their links with the polar substorms and the injection of hot plasma at the geostationary orbit

    International Nuclear Information System (INIS)

    Sauvaud, J.A.; Winckler, J.R.

    1981-01-01

    The aim of this paper is to analyse the results obtained aboard geostationary satellites and on the ground, in the auroral zone, on the dynamic changes in the outer radiation belts and their link with the time development of auroral forms during magnetospheric substorms. The measurements of high-energy particles, plasma, and magnetic induction at 6.6 Rsub(E) in the local midnight sector indicate the existence of a pre-expansion phase in substorms during which the outer belts move toward the Earth under the effect of the modification in the topology of the local magnetic induction. The pre-expansion phase coincides with an increase in the AE index, suggesting a direct link between the electrojet and the currents flowing across the tail of the magnetosphere. It also coincides in the auroral zone with the intensification and movement of the quiet arc system toward the equator. The phase is invariably terminated at the beginning of the expansion of the substorm by the break-up of the auroral arcs and the injection of hot plasma at the geostationary orbit near local midnight under the action of the induced electric field associated with the collapse of the geomagnetic field force lines. The study of the data, event by event, shows the complexity of phenomena which may be involved during the pre-expansion phase particularly with the possible presence of pseudo-substorms or aborted (minor) substorms which do not modify the general evolution described above [fr

  9. Solar UV radiation variations and their stratospheric and climatic effects

    Science.gov (United States)

    Donnelly, R. F.; Heath, D. F.

    1985-01-01

    Nimbus-7 SBUV measurements of the short-term solar UV variations caused by solar rotation and active-region evolution have determined the amplitude and wavelength dependence for the active-region component of solar UV variations. Intermediate-term variations lasting several months are associated with rounds of major new active regions. The UV flux stays near the peak value during the current solar cycle variation for more than two years and peaks about two years later than the sunspot number. Nimbus-7 measurements have observed the concurrent stratospheric ozone variations caused by solar UV variations. There is now no doubt that solar UV variations are an important cause of short- and long-term stratospheric variations, but the strength of the coupling to the troposphere and to climate has not yet been proven.

  10. Belt of Yotvings. Radioecology

    International Nuclear Information System (INIS)

    Mazheika, J.; Petroshius, R.; Strzelecki, R.; Wolkovitcz, S.; Lewandowski, P.

    1997-01-01

    Full text: The map of gamma radiation dose of 'Belt of Yotvings' area displays the summarized gamma radiation coming from natural radionuclides of 238 U, 232 Th, 40 K and from cesium isotopes 137 Cs, 134 Cs, artificially supplied into the environment after the Chernobyl disaster. The average value of gamma radiation dose for 'Belt of Yotvings' area is 44.2 n Gy/h, with a distinct regional differentiation. The content of uranium varies from 0 to 4.5 g/t, with the average value of about 1.4 g/t. Thorium content varies from 0 to 10.3 g/t, with the average value of 4.3 g/t. Potassium content varies from 0.1 up to 2.5 %, with the average value of 1.2 %. The concentration of caesium radioisotopes reaches up to 11.6 kBq/m 2 , the average value being 3.8 kBq/m 2 . Radon concentration in soil air has been determined in 55 sites (83 analyses). Radon concentration has been noticed in volumes from trace amounts up to 55 kBq/m3.The radioecological mapping has documented that the highest concentrations of natural radioisotopes and, correspondingly, the highest total gamma radiation dose were observed in the northeastern part of the area studied, which is covered by clay-silty glaciolacustrine deposits. Slightly lower values are typical for the whole northwestern part of 'Belt of Yotvings'. Very low contents of radioactive elements and low total radiation doses are typical for eolian and sandur sands, occurring south-eastward from the line Augustow-Veisiejai. The Chernobyl NPP accident polluted the studied region with artificial cesium radioisotopes un significantly. The concentrations are low and they involve no radioecological hazard. The investigation of radon concentration in soil air have revealed several places affected by high radon emanation. These places should be studied in a more detailed way

  11. Variations in the width of the Indo-Pacific tropical rain belt over the last millennium: synthesis of stalagmite proxy records and climate model simulations

    Science.gov (United States)

    Ummenhofer, Caroline; Denniston, Rhawn

    2017-04-01

    The seasonal north-south migration of the intertropical convergence zone defines the tropical rain belt (TRB), a region of enormous terrestrial biodiversity and home to 40% of the world's population. The TRB is dynamic and has been shown to shift south as a coherent system during periods of Northern Hemisphere cooling. However, recent studies of Indo-Pacific hydroclimate suggest that during the Little Ice Age (AD 1400-1850), the TRB in this region contracted rather than being displaced uniformly southward. This behaviour is not well understood, particularly during climatic fluctuations less pronounced than those of the Little Ice Age, the largest centennial-scale cool period of the last millennium. Using state-of-the-art climate model simulations conducted as part of the Last Millennium Ensemble with the Community Earth System Model (CESM), we evaluate variations in the width of the Indo-Pacific TRB, as well as movements in the position of its northward and southward edges, across a range of timescales over the pre-Industrial portion of the last millennium (AD 850-1850). The climate model results complement a recent reconstruction of late Holocene variability of the Indo-Pacific TRB, based on a precisely-dated, monsoon-sensitive stalagmite reconstruction from northern Australia (cave KNI-51), located at the southern edge of the TRB and thus highly sensitive to variations at its southern edge. Integrating KNI-51 with a record from Dongge Cave in southern China allows a stalagmite-based TRB reconstruction. Our results reveal that rather than shifting meridionally, the Indo-Pacific TRB expanded and contracted over multidecadal/centennial time scales during the late Holocene, with symmetric weakening/strengthening of summer monsoons in the Northern and Southern Hemispheres of the Indo-Pacific (the East Asian summer monsoon in China and the Australian summer monsoon in northern Australia). Links to large-scale climatic conditions across the Indo-Pacific region

  12. The Contribution of Compressional Magnetic Pumping to the Energization of the Earth's Outer Electron Radiation Belt During High-Speed Stream-Driven Storms

    Science.gov (United States)

    Borovsky, Joseph E.; Horne, Richard B.; Meredith, Nigel P.

    2017-12-01

    Compressional magnetic pumping is an interaction between cyclic magnetic compressions and pitch angle scattering with the scattering acting as a catalyst to allow the cyclic compressions to energize particles. Compressional magnetic pumping of the outer electron radiation belt at geosynchronous orbit in the dayside magnetosphere is analyzed by means of computer simulations, wherein solar wind compressions of the dayside magnetosphere energize electrons with electron pitch angle scattering by chorus waves and by electromagnetic ion cyclotron (EMIC) waves. The magnetic pumping is found to produce a weak bulk heating of the electron radiation belt, and it also produces an energetic tail on the electron energy distribution. The amount of energization depends on the robustness of the solar wind compressions and on the amplitude of the chorus and/or EMIC waves. Chorus-catalyzed pumping is better at energizing medium-energy (50-200 keV) electrons than it is at energizing higher-energy electrons; at high energies (500 keV-2 MeV) EMIC-catalyzed pumping is a stronger energizer. The magnetic pumping simulation results are compared with energy diffusion calculations for chorus waves in the dayside magnetosphere; in general, compressional magnetic pumping is found to be weaker at accelerating electrons than is chorus-driven energy diffusion. In circumstances when solar wind compressions are robust and when EMIC waves are present in the dayside magnetosphere without the presence of chorus, EMIC-catalyzed magnetic pumping could be the dominant energization mechanism in the dayside magnetosphere, but at such times loss cone losses will be strong.

  13. Radiation-induced transmission spectral variations of Ce3+-doped heavy germanate glasses

    International Nuclear Information System (INIS)

    Yang Yunxia; Baccaro, S.; Cecilia, A.; Rao Jinhua; Zhang Junbiao; Xia Fang; Chen Guorong

    2005-01-01

    Radiation-induced transmission spectral variations of Ce 3+ -doped heavy germanate glasses used as scintillating materials are presented. Glass matrix contains mainly GeO 2 , BaO and Gd 2 O 3 with a density higher than 5 g/cm 3 . Glasses are melted in the different atmosphere. The transmission spectra of glasses before and after radiation treatments are measured and compared. Unlike exhibiting the monotonous deterioration effect on the glass matrix, radiation plays the radiation protection role, even making enhanced transmission of Ce 3+ -doped glasses, depending upon glass melting atmosphere and radiation dose. Radiation-induced reducing and oxidizing mechanism is proposed to explain phenomena

  14. Some observations of the variations in natural gamma radiation due to rainfall

    International Nuclear Information System (INIS)

    Minato, S.

    1980-01-01

    Results of observations of variations in natural gamma-radiation flux densities due to rainfall are presented and discussed in relation to rate of rainfall. Variations of fluences with amounts of rainfall are also described. It is concluded that the frequency distribution of the ratio of the fluence to the amount of rainfall has a trend to be lognormal

  15. Analysis of variations in the dose delivered in radiation therapy

    International Nuclear Information System (INIS)

    Feld, D.B.

    1996-01-01

    The outcome of radiotherapy in cancer care is heavily dependent on the quality of the treatment. This work presents a review of how daily practice and the current availability of equipment for treatment planning and simulating as well as a number of other factors affect the radiation therapy quality in Argentina. The establishment of refreshing courses for all types of staffs involved in the treatments, modernization of equipment and strict routines in patient set up and quality control would give a significant contribution to a higher quality in radiation therapy. (author). 3 refs

  16. Analysis of variations in the dose delivered in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Feld, D B [Comision Nacional de Energia Atomica, Radiacion-Gcia de Aplicaciones, Buenos Aires (Argentina). Div. Dosimetria

    1996-08-01

    The outcome of radiotherapy in cancer care is heavily dependent on the quality of the treatment. This work presents a review of how daily practice and the current availability of equipment for treatment planning and simulating as well as a number of other factors affect the radiation therapy quality in Argentina. The establishment of refreshing courses for all types of staffs involved in the treatments, modernization of equipment and strict routines in patient set up and quality control would give a significant contribution to a higher quality in radiation therapy. (author). 3 refs.

  17. Green operations of belt conveyors by means of speed control

    NARCIS (Netherlands)

    He, D.; Pang, Y.; Lodewijks, G.

    2017-01-01

    Belt conveyors can be partially loaded due to the variation of bulk material flow loaded onto the conveyor. Speed control attempts to reduce the belt conveyor energy consumption and to enable the green operations of belt conveyors. Current research of speed control rarely takes the conveyor dynamics

  18. Seat belt reminders.

    NARCIS (Netherlands)

    2008-01-01

    Seat belts are an effective way of reducing the number or road deaths and severe road injuries in crashes. Seat belt reminders warn car drivers and passengers if the seat belt is not fastened. This can be done by a visual signal or an acoustic signal or by a combination of the two. Seat belt

  19. Solar ultraviolet radiation induced variations in the stratosphere and mesosphere

    Science.gov (United States)

    Hood, L. L.

    1987-01-01

    The detectability and interpretation of short-term solar UV induced responses of middle atmospheric ozone, temperature, and dynamics are reviewed. The detectability of solar UV induced perturbations in the middle atmosphere is studied in terms of seasonal and endogenic dynamical variations. The interpretation of low-latitude ozone and possible temperature responses on the solar rotation time scale is examined. The use of these data to constrain or test photochemical model predictions is discussed.

  20. Pratt & Whitney aircraft nuclear J-8 turbojet engine performance variation with radiator diameter

    International Nuclear Information System (INIS)

    Larson, John W.

    1960-01-01

    The variation of engine performance with liquid metal radiator diameter and flight altitude has been estimated for both the 1600F NaK and 1800F NaK radiators at Mach 0.6 and hot day atmospheric conditions. The net thrust, air flow and reactor power is presented in 3 figures for the Pratt & Whitney Aircraft J-58 engine with the 1600F NaK radiator. The net thrust, air flow and reactor power for the 1800F NaK radiator are also presented in figures.

  1. Deduction of the rates of radial diffusion of protons from the structure of the Earth's radiation belts

    Science.gov (United States)

    Kovtyukh, Alexander S.

    2016-11-01

    From the data on the fluxes and energy spectra of protons with an equatorial pitch angle of α0 ≈ 90° during quiet and slightly disturbed (Kp ≤ 2) periods, I directly calculated the value DLL, which is a measure of the rate of radial transport (diffusion) of trapped particles. This is done by successively solving the systems (chains) of integrodifferential equations which describe the balance of radial transport/acceleration and ionization losses of low-energy protons of the stationary belt. This was done for the first time. For these calculations, I used data of International Sun-Earth Explorer 1 (ISEE-1) for protons with an energy of 24 to 2081 keV at L = 2-10 and data of Explorer-45 for protons with an energy of 78.6 to 872 keV at L = 2-5. Ionization losses of protons (Coulomb losses and charge exchange) were calculated on the basis of modern models of the plasmasphere and the exosphere. It is shown that for protons with μ from ˜ 0.7 to ˜ 7 keV nT-1 at L ≈ 4.5-10, the functions of DLL can be approximated by the following equivalent expressions: DLL ≈ 4.9 × 10-14μ-4.1L8.2 or DLL ≈ 1.3 × 105(EL)-4.1 or DLL ≈ 1.2 × 10-9fd-4.1, where fd is the drift frequency of the protons (in mHz), DLL is measured in s-1, E is measured in kiloelectronvolt and μ is measured in kiloelectronvolt per nanotesla. These results are consistent with the radial diffusion of particles under the action of the electric field fluctuations (pulsations) in the range of Pc6 and contradict the mechanism of the radial diffusion of particles under the action of sudden impulses (SIs) of the magnetic field and also under the action of substorm impulses of the electric field. During magnetic storms DLL increases, and the expressions for DLL obtained here can change completely.

  2. Deduction of the rates of radial diffusion of protons from the structure of the Earth's radiation belts

    Directory of Open Access Journals (Sweden)

    A. S. Kovtyukh

    2016-11-01

    Full Text Available From the data on the fluxes and energy spectra of protons with an equatorial pitch angle of α0 ≈ 90° during quiet and slightly disturbed (Kp ≤ 2 periods, I directly calculated the value DLL, which is a measure of the rate of radial transport (diffusion of trapped particles. This is done by successively solving the systems (chains of integrodifferential equations which describe the balance of radial transport/acceleration and ionization losses of low-energy protons of the stationary belt. This was done for the first time. For these calculations, I used data of International Sun–Earth Explorer 1 (ISEE-1 for protons with an energy of 24 to 2081 keV at L = 2–10 and data of Explorer-45 for protons with an energy of 78.6 to 872 keV at L = 2–5. Ionization losses of protons (Coulomb losses and charge exchange were calculated on the basis of modern models of the plasmasphere and the exosphere. It is shown that for protons with μ from  ∼ 0.7 to ∼ 7 keV nT−1 at L ≈ 4.5–10, the functions of DLL can be approximated by the following equivalent expressions: DLL ≈ 4.9 × 10−14μ−4.1L8.2 or DLL ≈ 1.3 × 105(EL−4.1 or DLL ≈ 1.2 × 10−9fd−4.1, where fd is the drift frequency of the protons (in mHz, DLL is measured in s−1, E is measured in kiloelectronvolt and μ is measured in kiloelectronvolt per nanotesla. These results are consistent with the radial diffusion of particles under the action of the electric field fluctuations (pulsations in the range of Pc6 and contradict the mechanism of the radial diffusion of particles under the action of sudden impulses (SIs of the magnetic field and also under the action of substorm impulses of the electric field. During magnetic storms DLL increases, and the expressions for DLL obtained here can change completely.

  3. Deduction of the rates of radial diffusion of protons from the structure of the Earth's radiation belts

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

    From the data on the fluxes and energy spectra of protons with an equatorial pitch angle of α{sub 0} ∼ 90 during quiet and slightly disturbed (Kp≤2) periods, I directly calculated the value D{sub LL}, which is a measure of the rate of radial transport (diffusion) of trapped particles. This is done by successively solving the systems (chains) of integrodifferential equations which describe the balance of radial transport/acceleration and ionization losses of low-energy protons of the stationary belt. This was done for the first time. For these calculations, I used data of International Sun-Earth Explorer 1 (ISEE-1) for protons with an energy of 24 to 2081 keV at L = 2-10 and data of Explorer-45 for protons with an energy of 78.6 to 872 keV at L = 2-5. Ionization losses of protons (Coulomb losses and charge exchange) were calculated on the basis of modern models of the plasmasphere and the exosphere. It is shown that for protons with μ from ∝0.7 to ∝7 keV nT{sup -1} at L ∼ 4.5-10, the functions of D{sub LL} can be approximated by the following equivalent expressions: D{sub LL} ∼ 4.9 x 10{sup -14}μ{sup -4.1}L{sup 8.2} or D{sub LL} ∼ 1.3 x 10{sup 5}(EL){sup -4.1} or D{sub LL} ∼ 1.2 x 10{sup -9}f{sub d}{sup -4.1}, where f{sub d} is the drift frequency of the protons (in mHz), D{sub LL} is measured in s{sup -1}, E is measured in kiloelectronvolt and μ is measured in kiloelectronvolt per nanotesla. These results are consistent with the radial diffusion of particles under the action of the electric field fluctuations (pulsations) in the range of Pc6 and contradict the mechanism of the radial diffusion of particles under the action of sudden impulses (SIs) of the magnetic field and also under the action of substorm impulses of the electric field. During magnetic storms D{sub LL} increases, and the expressions for D{sub LL} obtained here can change completely.

  4. Belt attachment and system

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abraham D.; Davidson, Erick M.

    2018-03-06

    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.

  5. Annual and semiannual variations of the cosmic radiation

    International Nuclear Information System (INIS)

    Khor, H.P.; Kwok, W.K.; Owens, A.J.

    1979-01-01

    We determine the annual and semiannual harmonics in the Deep River Neutron Monitor counting rate for the years 1960--1975. A new Fourier analysis technique is used to eliminate solar cycle variations, an we discuss the statistical errors in the determination of the harmonics. The annual and semiannual waves changed markedly from year to year. The yearly harmonic has an average amplitude approx.0.6% with a maximum in early March, corresponding to a southward anisotropy of approx.5%/AU perpendicular to the solar equatorial plane. The semiannual harmonic shows no phase coherence and its average amplitude is only marginally significant, < or approx. =0.2%

  6. 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)

    de Pater, I.

    1981-01-01

    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 O 4 model) and Davis, Jones and Smith (quoted in Smith and Gulkis [1979]) (the P 11 (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 O 4 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

  7. 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.

  8. Storm time variation of radiative cooling of thermosphere by nitric oxide emission

    Science.gov (United States)

    Krishna, M. V. Sunil; Bag, Tikemani; Bharti, Gaurav

    2016-07-01

    The fundamental vibration-rotation band emission (Δν=1, Δ j=0,± 1) by nitric oxide (NO) at 5.3 µm is one of the most important cooling mechanisms in thermosphere. The collisional vibrational excitation of NO(ν=0) by impact with atomic oxygen is the main source of vibrationally excited nitric oxide. The variation of NO density depends on latitude, longitude and season. The present study aims to understand how the radiative flux gets influenced by the severe geomagnetic storm conditions. The variation of Nitric Oxide (NO) radiative flux exiting thermosphere is studied during the superstorm event of 7-12 November, 2004. The observations of TIMED/SABER suggest a strong anti-correlation with the O/N_2 ratio observed by GUVI during the same period. On a global scale the NO radiative flux showed an enhancement during the main phase on 8 November, 2004, whereas maximum depletion in O/N_2 is observed on 10 November, 2004. Both O/N_2 and NO radiative flux were found to propagate equatorward due to the effect of meridional wind resulting from joule and particle heating in polar region. Larger penetrations is observed in western longitude sectors. These observed variations are effectively connected to the variations in neutral densities. In the equatorial sectors, O/N_2 shows enhancement but almost no variation in radiative flux is observed. The possible reasons for the observed variations in NO radiative emission and O/N_2 ratios are discussed in the light of equator ward increase in the densities and prompt penetration.

  9. Parametric excitation of very low frequency (VLF) electromagnetic whistler waves and interaction with energetic electrons in radiation belt

    Science.gov (United States)

    Sotnikov, V.; Kim, T.; Caplinger, J.; Main, D.; Mishin, E.; Gershenzon, N.; Genoni, T.; Paraschiv, I.; Rose, D.

    2018-04-01

    The concept of a parametric antenna in ionospheric plasma is analyzed. Such antennas are capable of exciting electromagnetic radiation fields, specifically the creation of whistler waves generated at the very low frequency (VLF) range, which are also capable of propagating large distances away from the source region. The mechanism of whistler wave generation is considered a parametric interaction of quasi-electrostatic whistler waves (also known as low oblique resonance (LOR) oscillations) excited by a conventional loop antenna. The interaction of LOR waves with quasi-neutral density perturbations in the near field of an antenna gives rise to electromagnetic whistler waves on combination frequencies. It is shown in this work that the amplitude of these waves can considerably exceed the amplitude of whistler waves directly excited by a loop. Additionally, particle-in-cell simulations, which demonstrate the excitation and spatial structure of VLF waves excited by a loop antenna, are presented. Possible applications including the wave-particle interactions to mitigate performance anomalies of low Earth orbit satellites, active space experiments, communication via VLF waves, and modification experiments in the ionosphere will be discussed.

  10. Synaptic ribbon. Conveyor belt or safety belt?

    Science.gov (United States)

    Parsons, T D; Sterling, P

    2003-02-06

    The synaptic ribbon in neurons that release transmitter via graded potentials has been considered as a conveyor belt that actively moves vesicles toward their release sites. But evidence has accumulated to the contrary, and it now seems plausible that the ribbon serves instead as a safety belt to tether vesicles stably in mutual contact and thus facilitate multivesicular release by compound exocytosis.

  11. Lap belts and three-point belts.

    NARCIS (Netherlands)

    Kampen, L.T.B. van & Edelman, A.

    1975-01-01

    Results of the swov-accident investigation prove that if there are any differences in the effectiveness of lap belts and three-point belts, these are so small that they cannot form a basis for giving preference to one type over the other. Furthermore, in spite of the results of this investigation

  12. Induction of Genetic Variation with Recurrent Gamma Radiation in Centipedegrass (Eremochloa ophiuroides)

    International Nuclear Information System (INIS)

    Lim Keun- Bal; Rim Yong-Woo

    1998-01-01

    Centipedegrass (Eremochloa ophiuroides) is a popular lawn grass in the southeastern USA. It has a naturally light green color and grows well on a wide range of soil types. Studies show limited morphological variation present in centipedegrass germplasm. To obtain the high morphological variation, plants were established from the irradiated seed at 10 Kr, allowed to interpollinate and harvested bulk seed, and then irradiated again for the next cycles. Morphological characteristics were measured in the 5 genetic varition lines (TC201:cv. Common and non irradiated, TC202:4th cycles, TC241:6th cycles, TC306:8th cycles, and TC318:5th cycles) induced by recurrent gamma radiation. The ranges of variation of recurrently radiated centipedegrass lines TC202, TC241, and TC306 except TC318(TifBlair) for the stolons per plant, total stolon length per plant, longest stolon length, leaf length and width at top-most exposed internode were wider than those of non-irradiated line (TC201). Recurrent gamma radiation was very effective to enlarge the ranges of variation of morphological characteristics in reproductive organ like stolons of centipedegrass. The effect of quantity of gamma ray irradiation cycles on the means and ranges of variation in the morphological characteristics of centipedegrass was not regularly tended

  13. Experimental study of variations in background radiation and the effect on Nuclear Car Wash sensitivity

    International Nuclear Information System (INIS)

    Church, J; Slaughter, D; Norman, E; Asztalos, S; Biltoft, P

    2007-01-01

    Error rates in a cargo screening system such as the Nuclear Car Wash [1-7] depend on the standard deviation of the background radiation count rate. Because the Nuclear Car Wash is an active interrogation technique, the radiation signal for fissile material must be detected above a background count rate consisting of cosmic, ambient, and neutron-activated radiations. It was suggested previously [1,6] that the Corresponding negative repercussions for the sensitivity of the system were shown. Therefore, to assure the most accurate estimation of the variation, experiments have been performed to quantify components of the actual variance in the background count rate, including variations in generator power, irradiation time, and container contents. The background variance is determined by these experiments to be a factor of 2 smaller than values assumed in previous analyses, resulting in substantially improved projections of system performance for the Nuclear Car Wash

  14. Observations of MeV electrons in Jupiter's innermost radiation belts and polar regions by the Juno radiation monitoring investigation: Perijoves 1 and 3

    DEFF Research Database (Denmark)

    Becker, Heidi N.; Santos-Costa, Daniel; Jørgensen, John Leif

    2017-01-01

    Juno's “Perijove 1” (27 August 2016) and “Perijove 3” (11 December 2016) flybys through the innermost region of Jupiter's magnetosphere (radial distances ... Investigation collected particle counts and noise signatures from penetrating high-energy particle impacts in images acquired by the Stellar Reference Unit and Advanced Stellar Compass star trackers, and the Jupiter Infrared Auroral Mapper infrared imager. This coordinated observation campaign sampled radiation...

  15. Belt Aligning Revisited

    Directory of Open Access Journals (Sweden)

    Yurchenko Vadim

    2017-01-01

    parts of the conveyor, the sides of the belt wear intensively. This results in reducing the life of the belt. The reasons for this phenomenon are well investigated, but the difficulty lies in the fact that they all act simultaneously. The belt misalignment prevention can be carried out in two ways: by minimizing the effect of causes and by aligning the belt. The construction of aligning devices and errors encountered in practice are considered in this paper. Self-aligning roller supports rotational in plan view are recommended as a means of combating the belt misalignment.

  16. Seasonal variation of solar radiation and underwater irradiance in the Seto inland sea

    International Nuclear Information System (INIS)

    Endo, T.; Matsuda, O.; Imabayashi, H.

    1983-01-01

    The recent rapid eutrophication of the coastal seas of Japan has had a remarkable effect on the turbidity and transparency of the sea water, hence on the attenuation of underwater irradiance, which in turn influences the phytoplankton communities and primary productivity of the area. The present study deals with the continuous three years observation of the total short-wave radiation, direct short-wave radiation, diffused short-wave radiation and photosynthetically active radiation of tlle Seto Inland Sea. Along with these observations, reflected short-wave radiation from the sea and transmitted short-wave radiation into the sea were determined. The availability of solar radiation for primary production, vertical distribution of spectral irradiance and attenuation coefficient were also discussed in relation to the optical water type of the region. 1. A typical seasonal variation in the monthly mean daily solar radiation (total short-wave radiation) was observed, with a maximal value of 17.0 MJ 2 in July and minimal values of 7.4 to 7.5 MJ 2 through November to January. 2. Seasonal variation of direct short-wave radiation was nearly identical to that of total short-wave radiation, with 9.3 MJ 2 at maximum and 4.1MJ 2 at minimum. Diffused short-wave radiation increased in June and decreased in January. The ratio of diffused short-wave radiation to total short-wave radiation ranged from 394000 62% with an average of 49%.0 3. Seasonal variation of photosynthetically active radiation was very similar to that of direct short-wave radiation, with values of 7.3 MJ 2 in July and of 3.3 MJ 2 in December 4. The albedo at the sea surface changed according to the incidence angle and surface conditions. Average daily values ranged from 2.9% on a fine summer day to 10% on an overcasted day in winter. 5. Underwater irradiance at a depth of 50cm varied widely according to such parameters as turbidity and the surface condition of the water. Observation revealed a remarkable decrease

  17. Phylogenomics Reveals Three Sources of Adaptive Variation during a Rapid Radiation.

    Directory of Open Access Journals (Sweden)

    James B Pease

    2016-02-01

    Full Text Available Speciation events often occur in rapid bursts of diversification, but the ecological and genetic factors that promote these radiations are still much debated. Using whole transcriptomes from all 13 species in the ecologically and reproductively diverse wild tomato clade (Solanum sect. Lycopersicon, we infer the species phylogeny and patterns of genetic diversity in this group. Despite widespread phylogenetic discordance due to the sorting of ancestral variation, we date the origin of this radiation to approximately 2.5 million years ago and find evidence for at least three sources of adaptive genetic variation that fuel diversification. First, we detect introgression both historically between early-branching lineages and recently between individual populations, at specific loci whose functions indicate likely adaptive benefits. Second, we find evidence of lineage-specific de novo evolution for many genes, including loci involved in the production of red fruit color. Finally, using a "PhyloGWAS" approach, we detect environment-specific sorting of ancestral variation among populations that come from different species but share common environmental conditions. Estimated across the whole clade, small but substantial and approximately equal fractions of the euchromatic portion of the genome are inferred to contribute to each of these three sources of adaptive genetic variation. These results indicate that multiple genetic sources can promote rapid diversification and speciation in response to new ecological opportunity, in agreement with our emerging phylogenomic understanding of the complexity of both ancient and recent species radiations.

  18. Investigation of variations and trends in solar radiation in Klang Valley Region, Malaysia

    International Nuclear Information System (INIS)

    Mohamed Elnour Yassen, Jamaluddin Mohd Jahi

    2006-01-01

    The objective of this study is to investigate variations and trends in the global solar radiation in Klang Valley region. The least square method was used for the trend analysis. Since the available time series covers 27 years, linear regression was preferred for the trend analysis. The linear trend is used mainly to test the change in solar radiation and to set limits on the rate of change. Trend line and values and significance levels of the slopes have been found. The seasonal and the annual average values were computed from the monthly average radiation data. The seasonal and annual average solar radiation values were designated as dependent variables, and thus, were fitted linearly for season and annual means for each station. The results showed that the mean of maximum incoming global radiation in Sepember with a value of 21.1 MJ m-2 at Petaling Jaya, while the mean minimum in November and December with values of 10.7 and 10.9 MJ m-2 at Petaling Jaya. The low amounts of solar radiation received in November and December are due to greater cloudiness during the period coinciding with the northeast monsoon season. On rainy days, very little global solar radiation received in November and December are due to greater cloudiness during the period coinciding with the northeast monsoon season. On rainy days, very little global solar radiation is received. The distribution of the seasonal mean values of solar radiation exhibits a high symmetry. Inter-monsoon seasons (April-May) and (October-November) show a similar behavior, just like the northeast monsoon season. The overall average rate of change in global solar radiation during 1975-2002 and 1977-2000 is represented by the slope of the linear regression was small (-0.126 and -0.314 MJ m-2 per year for Subang Airport and Petaling Jaya respectively)

  19. A long-lived refilling event of the slot region between the Van Allen radiation belts from Nov 2004 to Jan 2005

    Science.gov (United States)

    Yang, X.

    2015-12-01

    A powerful relativistic electron enhancement in the slot region between the inner and outer radiation belts is investigated by multi-satellites measurements. The measurement from Space Particle Component Detectors (SPCDs) aboard Fengyun-1 indicates that the relativistic electron (>1.6MeV) flux began to enhance obviously on early 10 November with the flux peak fixed at L~3.0. In the next day, the relativistic electron populations increased dramatically. Subsequently, the flux had been enhancing slowly, but unceasingly, until 17 November, and the maximum flux reached up to 7.8×104 cm-2·sr-1·s-1 at last. The flux peak fixed at L~3.0 and the very slow decay rate in this event make it to be an unusual long-lived slot region refilling event. We trace the cause of the event back to the interplanetary environment and find that there were two evident magnetic cloud constructions: dramatically enhanced magnetic field strength and long and smooth rotation of field vector from late 7 to 8 November and from late 9 to 10 November, respectively; solar wind speed increased in 'step-like' fashion on late 7 November and persisted the level of high speed >560 km·s-1 for about 124 hours. Owed to the interplanetary disturbances, very strong magnetic storms and substorms occurred in the magnetosphere. Responding to the extraordinarily magnetic perturbations, the plasmasphere shrank sharply. The location of plasmapause inferred from Dst indicates that the plasmapause shrank inward to as low as L~2.5. On account of these magnetospheric conditions, strong chorus emissions are expected near the earth. In fact, the STAFF on Cluster mission measured intensive whistler mode chorus emissions on 10 and 12 November, corresponding to the period of the remarkable enhancement of relativistic electron. Furthermore, we investigate the radial profile of phase space density (PSD) by electron flux from multi-satellites, and the evolution of the phase space density profile reveals that the local

  20. Variation in the thermionic work function of semiconductor powders exposed to electromagnetic radiation

    Science.gov (United States)

    Bourasseau, S.; Martin, J. R.; Juillet, F.; Teichner, S. J.

    1977-01-01

    The study of the variation of thermoelectronic work function potential of TiO2 in the presence of isobutane shows that this gas is not adsorbed on this solid, in either the presence or the absence of ultraviolet radiation. These results, as well as those obtained in a previous work, lead to the mechanism of the photo-oxidation of isobutane at room temperature, in which excited atomic oxygen is the active species.

  1. The Response of the Ocean Thermal Skin Layer to Variations in Incident Infrared Radiation

    Science.gov (United States)

    Wong, Elizabeth W.; Minnett, Peter J.

    2018-04-01

    Ocean warming trends are observed and coincide with the increase in concentrations of greenhouse gases in the atmosphere resulting from human activities. At the ocean surface, most of the incoming infrared (IR) radiation is absorbed within the top micrometers of the ocean's surface where the thermal skin layer (TSL) exists. Thus, the incident IR radiation does not directly heat the upper few meters of the ocean. This paper investigates the physical mechanism between the absorption of IR radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that given the heat lost through the air-sea interface is controlled by the TSL, the TSL adjusts in response to variations in incident IR radiation to maintain the surface heat loss. This modulates the flow of heat from below and hence controls upper ocean heat content. This hypothesis is tested using the increase in incoming longwave radiation from clouds and analyzing vertical temperature profiles in the TSL retrieved from sea-surface emission spectra. The additional energy from the absorption of increasing IR radiation adjusts the curvature of the TSL such that the upward conduction of heat from the bulk of the ocean into the TSL is reduced. The additional energy absorbed within the TSL supports more of the surface heat loss. Thus, more heat beneath the TSL is retained leading to the observed increase in upper ocean heat content.

  2. The impact of diurnal variations of air traffic on contrail radiative forcing

    Directory of Open Access Journals (Sweden)

    N. Stuber

    2007-06-01

    Full Text Available We combined high resolution aircraft flight data from the EU Fifth Framework Programme project AERO2k with analysis data from the ECMWF's integrated forecast system to calculate diurnally resolved 3-D contrail cover. We scaled the contrail cover in order to match observational data for the Bakan area (eastern-Atlantic/western-Europe.

    We found that less than 40% of the global distance travelled by aircraft is due to flights during local night time. Yet, due to the cancellation of shortwave and longwave effects during daytime, night time flights contribute a disproportional 60% to the global annual mean forcing. Under clear sky conditions the night flights contribute even more disproportionally at 76%. There are pronounced regional variations in night flying and the associated radiative forcing. Over parts of the North Atlantic flight corridor 75% of air traffic and 84% of the forcing occurs during local night, whereas only 35% of flights are during local night in South-East Asia, yet these contribute 68% of the radiative forcing. In general, regions with a significant local contrail radiative forcing are also regions for which night time flights amount to less than half of the daily total of flights. Therefore, neglecting diurnal variations in air traffic/contrail cover by assuming a diurnal mean contrail cover can over-estimate the global mean radiative forcing by up to 30%.

  3. Belt drive construction improvement

    Directory of Open Access Journals (Sweden)

    I.Yu. Khomenko

    2012-08-01

    Full Text Available The possibility of the traction capacity increase of the belt drive TRK is examined. This was done for the purpose of air conditioning system of passenger car with double-generator system energy supplying. Belts XPC (made by the German firm «Continental ContiTech» testing were conducted. The results confirmed the possibility of their usage in order to improve belt drive TRK characteristics.

  4. Variation of molybdenum isotopes in molybdenite from porphyry and vein Mo deposits in the Gangdese metallogenic belt, Tibetan plateau and its implications

    Science.gov (United States)

    Wang, Yong; Zhou, Lian; Gao, Shan; Li, Jian-Wei; Hu, Zhi-Fang; Yang, Lu; Hu, Zhao-Chu

    2016-02-01

    We present Mo isotopic ratios of molybdenite from five porphyry molybdenum deposits (Chagele, Sharang, Jiru, Qulong, and Zhuonuo) and one quartz-molybdenite vein-type deposit (Jigongcun) along the Gangdese metallogenic belt in the Tibetan Plateau. These deposits represent a sequence of consecutive events of the India-Asia collision at different periods. Additional molybdenite samples from the Henderson Mo deposit (USA), the oceanic subduction-related El Teniente (Chile), and Bingham (USA) porphyry Cu-(Mo) deposits were analyzed for better understanding the controls on the Mo isotope systematics of molybdenite. The results show that molybdenite from Sharang, Jiru, Qulong, and Zhuonuo deposits have similar δ97Mo (˜0 ‰), in agreement with the values of the Henderson Mo deposit (-0.10 ‰). In contrast, samples from the Changle and Jigongcun deposit have δ97Mo of 0.85 ‰ to 0.88 ‰ and -0.48 %, respectively. Molybdenite from the El Teniente and Bingham deposits yields intermediate δ97Mo of 0.27 and 0.46 ‰, respectively. The Mo isotopes, combined with Nd isotope data of the ore-bearing porphyries, indicate that source of the ore-related magmas has fundamental effects on the Mo isotopic compositions of molybdenite. Our study indicates that molybdenite related to crustal-, and mantle-derived magmas has positive or negative δ97Mo values, respectively, whereas molybdenite from porphyries formed by crust-mantle mixing has δ97Mo close to 0 ‰. It is concluded that the Mo isotope composition in the porphyry system is a huge source signature, without relation to the tectonic setting under which the porphyry deposits formed.

  5. Transient Performance of Radiator on Engine Rpm Variation with AC Loading

    Directory of Open Access Journals (Sweden)

    Made Ricki Murti

    2012-11-01

    Full Text Available Radiator is one of heat exchanger applications that has a function to remove out of heat must be able to operate properly for allowed engine temperature limit. Vehicles that operate on the street usually driving with varying rpm so that the heat produced by the combustion process is not constant and then this study analyze the performance of radiators as a function of time (transient condition. Tests is done on the condition of operating the engine with five rpm variations, each for one hour with air conditioning load and without air-conditioning load. The data to be collected includ the inlet and outlet temperature of radiator and radiator fluid volume flow. The results obtained is heat exhausted rate as a performance radiator is increasing as with increasing of engine rpm and at load conditions with the AC produces heat exhausted rate is greater than AC without AC load. The heat exhausted rate in an hour of machine operation still shows the system operates at a transient condition due to there still exists a numerical increase in the heat exhausted rate as a function of time.

  6. Intraspecific Variation in Pines from the Trans-Mexican Volcanic Belt Grown under Two Watering Regimes: Implications for Management of Genetic Resources

    Directory of Open Access Journals (Sweden)

    Andrés Flores

    2018-01-01

    Full Text Available Management of forest genetic resources requires experimental data related to the genetic variation of the species and populations under different climatic conditions. Foresters also demand to know how the main selective drivers will influence the adaptability of the genetic resources. To assess the inter- and intraspecific variation and plasticity in seedling drought tolerance at a relevant genetic resource management scale, we tested the changes in growth and biomass allocation of seedlings of Pinus oocarpa, P. patula and P. pseudostrobus under two contrasting watering regimes. We found general significant intraspecific variation and intraspecific differences in plasticity, since both population and watering by population interaction were significant for all three species. All the species and populations share a common general avoidance mechanism (allometric adjustment of shoot/root biomass. However, the intraspecific variation and differences in phenotypic plasticity among populations modify the adaptation strategies of the species to drought. Some of the differences are related to the climatic conditions of the location of origin. We confirmed that even at reduced geographical scales, Mexican pines present differences in the response to water stress. The differences among species and populations are relevant in afforestation programs as well as in genetic conservation activities.

  7. 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.

  8. Seasonal variations of radon and the radiation exposure levels in Nerja cave, Spain

    International Nuclear Information System (INIS)

    Duenas, C.; Fernandez, M.C.; Canete, S.; Perez, M.; Gordo, E.

    2011-01-01

    222 Rn concentrations in the air in Nerja cave (Spain) (3 o 52'35''W 36 o 43'50''N) were measured by continuous monitoring using Alpha-Guard, Genitron instrument equipment. The 222 Rn measurements were carried out for a complete annual cycle in the different halls: Vestibule hall from July 2003 to June 2004, Ballet hall from July 2004 to June 2005 and Mirador hall from July 2005 to June 2006. Starting from the entrance of the cave we successively find the Vestibule hall, the Ballet hall and the Mirador hall. The range of 222 Rn levels were of 8-627 Bq m -3 for the Vestibule hall, 28-575 Bq m -3 for the Ballet hall and 38-578 Bq m -3 for the Mirador. The aim of this study was to detect seasonal variation patterns of 222 Rn concentrations. The seasonal variations of 222 Rn concentrations are discussed in relation to various meteorological factors measured inside and outside the cave. The radiation exposure levels for workers and tourists with different equilibrium factors have been evaluated. The radiation exposure levels for workers and tourists only represent a low percentage of the exposure guides for the general population. - Highlights: → The aim of the study was to detect seasonal variation of 222 Rn concentrations. → 222 Rn concentrations in the air-cave were measured by continuous monitoring. → The 222 Rn measurements were carried out in the different halls of the cave. → The radiation exposure levels for workers and tourists have been evaluated.

  9. Short and long term variation in ultraviolet radiation and multiple sclerosis

    DEFF Research Database (Denmark)

    Menni, Cristina; Lowell, Walter E; Bentzen, Joan

    2012-01-01

    We examined the role of ultraviolet radiation (UVR) in persons diagnosed with multiple sclerosis (MS) in four different populations, Italians, Danish, White and African Americans. We tested whether variation in UVR as determined by seasons (short term variation) and solar cycles (long term...... to study the pattern of month of birth distribution in patients with MS comparing with general population data. T-tests were employed to study solar cycles association with lifespan. A surplus of births was observed in June for White Americans. A decrease of births in October and November, though...... not significant after multiple testing correction, was observed in the three populations. In White American with MS overall, males and females, we found that solar cycle is associated with lifespan. We found that season and solar cycles have some role in MS susceptibility and life duration. However...

  10. Radiation balance at the surface in the city of São Paulo, Brazil: diurnal and seasonal variations

    NARCIS (Netherlands)

    Ferreira, M.J.; Oliveira, de A.P.; Soares, J.; Codato, G.; Wilde Barbaro, E.; Escobedo, J.F.

    2012-01-01

    The main goal of this work is to describe the diurnal and seasonal variations of the radiation balance components at the surface in the city of São Paulo based on observations carried out during 2004. Monthly average hourly values indicate that the amplitudes of the diurnal cycles of net radiation

  11. Methodology to estimate variations in solar radiation reaching densely forested slopes in mountainous terrain.

    Science.gov (United States)

    Sypka, Przemysław; Starzak, Rafał; Owsiak, Krzysztof

    2016-12-01

    Solar radiation reaching densely forested slopes is one of the main factors influencing the water balance between the atmosphere, tree stands and the soil. It also has a major impact on site productivity, spatial arrangement of vegetation structure as well as forest succession. This paper presents a methodology to estimate variations in solar radiation reaching tree stands in a small mountain valley. Measurements taken in three inter-forest meadows unambiguously showed the relationship between the amount of solar insolation and the shading effect caused mainly by the contour of surrounding tree stands. Therefore, appropriate knowledge of elevation, aspect and tilt angles of the analysed planes had to be taken into consideration during modelling. At critical times, especially in winter, the diffuse and reflected components of solar radiation only reached some of the sites studied as the beam component of solar radiation was totally blocked by the densely forested mountain slopes in the neighbourhood. The cross-section contours and elevation angles of all obstructions are estimated from a digital surface model including both digital elevation model and the height of tree stands. All the parameters in a simplified, empirical model of the solar insolation reaching a given horizontal surface within the research valley are dependent on the sky view factor (SVF). The presented simplified, empirical model and its parameterisation scheme should be easily adaptable to different complex terrains or mountain valleys characterised by diverse geometry or spatial orientation. The model was developed and validated (R 2  = 0.92 , σ = 0.54) based on measurements taken at research sites located in the Silesian Beskid Mountain Range. A thorough understanding of the factors determining the amount of solar radiation reaching woodlands ought to considerably expand the knowledge of the water exchange balance within forest complexes as well as the estimation of site

  12. Temporal variation of optimal UV exposure time over Korea: risks and benefits of surface UV radiation

    Science.gov (United States)

    Lee, Y. G.; Koo, J. H.

    2015-12-01

    Solar UV radiation in a wavelength range between 280 to 400 nm has both positive and negative influences on human body. Surface UV radiation is the main natural source of vitamin D, providing the promotion of bone and musculoskeletal health and reducing the risk of a number of cancers and other medical conditions. However, overexposure to surface UV radiation is significantly related with the majority of skin cancer, in addition other negative health effects such as sunburn, skin aging, and some forms of eye cataracts. Therefore, it is important to estimate the optimal UV exposure time, representing a balance between reducing negative health effects and maximizing sufficient vitamin D production. Previous studies calculated erythemal UV and vitamin-D UV from the measured and modelled spectral irradiances, respectively, by weighting CIE Erythema and Vitamin D3 generation functions (Kazantzidis et al., 2009; Fioletov et al., 2010). In particular, McKenzie et al. (2009) suggested the algorithm to estimate vitamin-D production UV from erythemal UV (or UV index) and determined the optimum conditions of UV exposure based on skin type Ⅱ according to the Fitzpatrick (1988). Recently, there are various demands for risks and benefits of surface UV radiation on public health over Korea, thus it is necessary to estimate optimal UV exposure time suitable to skin type of East Asians. This study examined the relationship between erythemally weighted UV (UVEry) and vitamin D weighted UV (UVVitD) over Korea during 2004-2012. The temporal variations of the ratio (UVVitD/UVEry) were also analyzed and the ratio as a function of UV index was applied in estimating the optimal UV exposure time. In summer with high surface UV radiation, short exposure time leaded to sufficient vitamin D and erythema and vice versa in winter. Thus, the balancing time in winter was enough to maximize UV benefits and minimize UV risks.

  13. Seasonal variations in terrestrial gamma radiation along river Ganges and implications to public health risk

    International Nuclear Information System (INIS)

    Sharma, P.; Meher, P.K.; Mishra, K.P.

    2016-01-01

    Measurement of exposure to terrestrial gamma radiation dose and determination of associated health hazard at river bank is of major importance due to the increasing tourism, bathing festivals and mythological beliefs. Present study was focused on measurement of absorbed dose rates as function of seasonal variation at designated locations along Ganges river in India. Portable dosimeter (plastic scintillation counter) was used for the measurement of absorbed dose rates. Subsequently, annual effective dose (AED) and excess lifetime cancer risk (ELCR) were calculated by the standard procedure. Results showed absorbed dose rates for Pre-monsoon ranged from 89.7 ± 4.03 to 115.0 ± 7.81 nSv/h with an average of 105.54 nSv/h. Post-monsoon measurements yielded values from 81.0 ± 7.00 to 105.6 ± 5.75 nSv/h with an average value of 90.8 nSv/h. Calculated average AED for Pre-monsoon period was found to be 0.13 mSv/y. Whereas, 0.11 mSv/y was the AED for the post-monsoon period. Furthermore, the calculated average ELCR values for pre-monsoon and post-monsoon were found to be 0.488 × 10 -3 and 0.418 × 10 -3 , respectively. This study reports significant seasonal variations in the terrestrial gamma radiation doses along the long stretch of Ganges river. (author)

  14. Plasmaspheric noise radiation during geomagnetic storms

    International Nuclear Information System (INIS)

    Larkina, V.I.; Likhter, Ya.I.

    1981-01-01

    Variations of plasmospheric background radiations during geomagnetic storms of different intensity are investigated. Used are results of ELF and VLF radiation measurements as well as electron fluxes of energies Esub(e)>40 keV carried out by Intercosmos 3 and Intercosmos 5 satellites. Dependences of radiation amplitude variations at 1.6 and 25 kHz frequencies on L shell for various geomagnetic activity in the day-time as well as data on variations of quasicaptured electron fluxes at Esub(e)>40 keV, are given. It is shown that experimental data agree with the existing theories of plasmospheric noise excitation. It is concluded that the plasmospheric noise excitation area Lsub(max) is always in the region of gap between radiation belts and inner slope of external radiation belt during magnetic storms. During magnetic storms Lsub(max) area moves simultaneously with the area, where particle flux of the external radiation belt is the most intensive [ru

  15. Internal radiation due to bioaccumulated natural radionuclides ({sup 238}U and {sup 226}Ra) in some wild plants sampled from Singhbhum Thrust Belt

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V K [Co-operative College, Jamshedpur (India). Botany Dept.; Geeta, [Jamshedpur Women` s College, Jamshedpur (India). Botany Dept.

    1995-01-01

    Estimation of radioactivity (Bq/Kg dry Wt.) due to bioaccumulated {sup 238}U,{sup 226}Ra was carried out in six species of native plants growing in the non-occupational settings of Singhbhum Thrust Belt (STB). Due to medicinal and other economic values, these plants are used by the local people in their day to day life. Among the six species, Echinops echinatus excelled in the pick-up process of radionuclides. The rank decreased in the order: Echinops>Vitex>Cleistanthus>Ocimum>Holorrhoena>Lantana. (author). 14 refs., 2 tabs.

  16. The JET belt limiter tiles

    International Nuclear Information System (INIS)

    Deksnis, E.

    1988-09-01

    The belt limiter system, comprising two full toroidal rings of limiter tiles, was installed in JET in 1987. In consists of water-cooled fins with the limiter material in form of tile inbetween. The tiles are designed to absorb heat fluxes during irradiation without the surface temperature exceeding 2000 0 C and to radiate this heat between pulses to the water cooled sink whose temperature is lower than that of the vacuum vessel. An important feature of the design is to maximise the area of the radiating surface facing the water cooled fin. This leads to a tile depth much greater than the width of the tile facing the heat flux. Limiter tiles intercept particles flowing out of the plasma through the area between the two belt limiter rings and through remaining surface area of the plasma column. Power deposition to a limiter tile depends strongly on the shape of the plasma, the edge plasma properties as well as on the surface profile of the tiles. This paper will discuss the methodology that was followed in producing an optimized surface profile of the tiles. This shaped profile has the feature that the resulting power deposition profile is roughly similar for a wide range of plasma parameters. (author)

  17. Bladder volume variations of cervical cancer patient in radiation therapy using ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jong Ho [Dept. of Radiation Oncology, Pusan National University Hospital, Pusan (Korea, Republic of)

    2016-12-15

    The bladder volume change was measured using ultrasonography for helping decrease the side effects and other organ variations in the location of radiation therapy for cervical cancer patients. An experiment was performed targeting patients who were treated with radiation therapy at PNUH within the period from September to December 2015. To maintain the bladder volume, each patient was instructed to drink 500 cc water before and after CT simulation, 60 minutes before the dry run. Also, the bladder volume was measured in each patient CT scan, and a 3D conformal therapy plan was designed. The bladder volumes measured before and after the CT simulation, dry run, and radiation treatment planning were compared and analyzed. The average volume and average error of the bladder that were obtained from the measurement based on the CT scan images had the lowest standard deviation in the CT simulation. This means that the values that were obtained before and after the CT simulation were statistically relevant and correlative. Moreover, the bladder volume measured via ultrasonography was larger size, the average volume in the CT scan. But the values that were obtained Dry run and after the CT simulation were not statistically relevant. Drinking a certain amount of water helps a patient maintain his/her bladder volume for a dry run. Even then, it is difficult to maintain the bladder volume for the dry run. Also, whether or not the patients followed the directions for the dry run correctly is important.

  18. Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059

    Directory of Open Access Journals (Sweden)

    U. Kotthoff

    2017-12-01

    Full Text Available Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial, paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059 over the past  ∼  8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index show that lacustrine conditions occurred in the Little Belt until  ∼  7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish–marine conditions of the Littorina Sea stage (more saline and warmer occurred within  ∼  200 years when the connection to the Kattegat became established after  ∼  7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86 can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant

  19. Belt conveying of minerals

    Energy Technology Data Exchange (ETDEWEB)

    Stace, L.R.; Yardley, E.D. [University of Nottingham, Nottingham (United Kingdom). School of Civil Engineering

    2008-02-15

    A discussion of the history and economics of conveyor applications sets the scene. Conveyor design is investigated in detail, covering power requirements, belt tensioning, and hardware. Principles regarding construction and joining of belts are outlined and a helpful and practical overview of relevant standards, belt test methods, and issues surrounding standardisation is given. Conveyor belt systems can represent a significant operational hazard, so the authors have set out to highlight the important area of safety, with consideration given to fire/electrical resistance, as well as the interface between personnel and conveyor systems - including nip points and operational issues such as man-riding. Selected case studies illustrate some practical aspects of installation and operation, at Selby mine in the UK and Prosper-Haniel Colliery in Germany and others. 3 apps.

  20. Space Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R.

    1968-01-01

    This booklet discusses three kinds of space radiation, cosmic rays, Van Allen Belts, and solar plasma. Cosmic rays are penetrating particles that we cannot see, hear or feel, which come from distant stars. Van Allen Belts, named after their discoverer are great belts of protons and electrons that the earth has captured in its magnetic trap. Solar plasma is a gaseous, electrically neutral mixture of positive and negative ions that the sun spews out from convulsed regions on its surface.

  1. Belt conveyor apparatus

    Science.gov (United States)

    Oakley, David J.; Bogart, Rex L.

    1987-01-01

    A belt conveyor apparatus according to this invention defines a conveyance path including a first pulley and at least a second pulley. An endless belt member is adapted for continuous travel about the pulleys and comprises a lower portion which engages the pulleys and an integral upper portion adapted to receive objects therein at a first location on said conveyance path and transport the objects to a second location for discharge. The upper belt portion includes an opposed pair of longitudinally disposed crest-like members, biased towards each other in a substantially abutting relationship. The crest-like members define therebetween a continuous, normally biased closed, channel along the upper belt portion. Means are disposed at the first and second locations and operatively associated with the belt member for urging the normally biased together crest-like members apart in order to provide access to the continuous channel whereby objects can be received into, or discharged from the channel. Motors are in communication with the conveyance path for effecting the travel of the endless belt member about the conveyance path. The conveyance path can be configured to include travel through two or more elevations and one or more directional changes in order to convey objects above, below and/or around existing structures.

  2. Variation of reflected radiation from all reflectors of a flat plate solar collector during a year

    International Nuclear Information System (INIS)

    Pavlović, Zoran T.; Kostić, Ljiljana T.

    2015-01-01

    In this paper the impact of flat plate reflectors (bottom, top, left and right reflectors) made of Al, on total solar radiation on a solar collector during a day time over a whole year is analyzed. An analytical model for determining optimum tilt angles of a collector and reflectors for any point on the Earth is proposed. Variations of reflectors' optimal inclination angles with changes of the collector's optimal tilt angle during the year are also calculated. Optimal inclination angles of the reflectors for the South directed solar collector are calculated and compared to experimental data. It is shown that optimal inclination of the bottom reflector is the lowest in December and the highest in June, while for the top reflector the lowest value is in June and the highest value is in December. On the other hand, optimal inclination of the left and right side reflectors for optimum tilt angle of the collector does not change during the year and it is 66°. It is found that intensity of the solar radiation on the collector increases for about 80% in the summer period (June–September) by using optimally inclined reflectors, in comparison to the collector without reflectors. - Highlights: • The impacts of flat plate reflectors on solar radiation on the collector are given. • The results of the optimal inclinations of reflectors during the year are shown. • The solar radiation on the collector with reflectors is 80% higher in the summer. • This model may be applied on thermal, PV, PV/T and energy harvesting systems

  3. Errors of isotope conveyor weigher caused by profile variations and shift of material

    International Nuclear Information System (INIS)

    Machaj, B.

    1977-01-01

    Results of investigations of isotope conveyor weigher in transmission geometry and with long plastic scintillator as a detector are presented in the paper. The results indicate that errors caused by material shift across the conveyor belt can be decreased by forming probe sensitivity to incident radiation along its axis by means of additional radiation absorbents. The errors caused by material profile variations can effectively be diminished by increase of photon energy. Application of 60 Co instead of 137 Cs ensured more than three times lower errors caused by profile variation. Errors caused by vertical movements of the belt with material, decrease considerably, when single point source situated in the center of the measuring head is replaced at least by two point sources situated out of the center, above the edges of the belt. (author)

  4. Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Valicenti, Richard K.; Sweet, John W.; Hauck, Walter W.; Hudes, Richard S.; Lee, Tony; Dicker, Adam P.; Waterman, Frank M.; Anne, Pramila R.; Corn, Benjamin W.; Galvin, James M.

    1999-01-01

    Purpose: Currently, three-dimensional conformal radiation therapy (3D-CRT) planning relies on the interpretation of computed tomography (CT) axial images for defining the clinical target volume (CTV). This study investigates the variation among multiple observers to define the CTV used in 3D-CRT for prostate cancer. Methods and Materials: Seven observers independently delineated the CTVs (prostate ± seminal vesicles [SV]) from the CT simulation data of 10 prostate cancer patients undergoing 3D-CRT. Six patients underwent CT simulation without the use of contrast material and serve as a control group. The other 4 had urethral and bladder opacification with contrast medium. To determine interobserver variation, we evaluated the derived volume, the maximum dimensions, and the isocenter for each examination of CTV. We assessed the reliability in the CTVs among the observers by correlating the variation for each class of measurements. This was estimated by intraclass correlation coefficient (ICC), with 1.00 defining absolute correlation. Results: For the prostate volumes, the ICC was 0.80 (95% confidence interval [CI]: 0.56-0.96). This changed to 0.92 (95% CI: 0.75-0.99) with the use of contrast material. Similarly, the maximal prostatic dimensions were reliable and improved. There was poor agreement in defining the SV. For this structure, the ICC never exceeded 0.28. The reliability of the isocenter was excellent, with the ICC exceeding 0.83 and 0.90 for the prostate ± SV, respectively. Conclusions: In 3D-CRT for prostate cancer, there was excellent agreement among multiple observers to define the prostate target volume but poor agreement to define the SV. The use of urethral and bladder contrast improved the reliability of localizing the prostate. For all CTVs, the isocenter was very reliable and should be used to compare the variation in 3D dosimetry among multiple observers

  5. Radiometric measurement independent of profile. Belt weighers

    International Nuclear Information System (INIS)

    Otto, J.

    1986-01-01

    Radiometric measuring techniques allow contactless determination of the material carried by belt conveyors. Data defining the material is obtained via attenuation of gamma rays passing through the material on the belt. The method applies the absorption law according to Lambert-Beer, which has to be corrected by a build-up factor because of the stray radiation induced by the Compton effect. The profile-dependent error observed with conventional radiometric belt weighers is caused by the non-linearity of the absorption law in connection with the simultaneous summation of the various partial rays in a detector. The scanning method allows separate evaluation of the partial rays' attenuation and thus yields the correct data of the material carried, regardless of the profile. The scanning method is applied on a finite number of scanning sections, and a residual error has to be taken into account. The stochastics of quantum emission and absorption leads to an error whose expectation value is to be taken into account in the scanning algorithm. As the conveyor belt is in motion during the process of measurements, only part of the material conveyed is irradiated. The resulting assessment error is investigated as a function of the autocorrelation function of the material on the belt. (orig./HP) [de

  6. A numerical analysis of antithetic variates in Monte Carlo radiation transport with geometrical surface splitting

    International Nuclear Information System (INIS)

    Sarkar, P.K.; Prasad, M.A.

    1989-01-01

    A numerical study for effective implementation of the antithetic variates technique with geometric splitting/Russian roulette in Monte Carlo radiation transport calculations is presented. The study is based on the theory of Monte Carlo errors where a set of coupled integral equations are solved for the first and second moments of the score and for the expected number of flights per particle history. Numerical results are obtained for particle transmission through an infinite homogeneous slab shield composed of an isotropically scattering medium. Two types of antithetic transformations are considered. The results indicate that the antithetic transformations always lead to reduction in variance and increase in efficiency provided optimal antithetic parameters are chosen. A substantial gain in efficiency is obtained by incorporating antithetic transformations in rule of thumb splitting. The advantage gained for thick slabs (∼20 mfp) with low scattering probability (0.1-0.5) is attractively large . (author). 27 refs., 9 tabs

  7. Possible individual variation in susceptibility to radiation-induced genetic changes

    International Nuclear Information System (INIS)

    Gentner, N.E.; Walker, J.A.

    1990-01-01

    Several studies have shown variation between individuals in radiosensitivity. A person could have a high level of cytogenetic indicator because of high exposure or high susceptibility. To relate spontaneous cytogenetic end-points to dose it is advisable to have a measure of both the spontaneous level and of induced susceptibility. These end points need to be compared in irradiated persons who have developed cancer versus those who have not, as a guide to what end points are appropriate for susceptibility to radiogenic cancer. The use of inbred rodent strains may not be appropriate to derive specific locus mutation data relevant to the human situation, in which large differences in susceptibility appear to exist. Variability in response because of differential DNA repair capacity should be kept in mind when evaluating existing human data. For accident situations, using acute exposures for testing susceptibility may be appropriate, but to be relevant to low dose, low dose rate exposures, more use of protracted dose delivery in testing is recommended. There is a need for international collaborative study where these different tests are done on the same donors at the same time. It might now be prudent for radiation protection to take into account the occurrence of critical groups in the population on the basis of their increased radiation sensitivity. (12 refs., 3 figs.)

  8. Spatial variation of natural radiation and childhood leukaemia incidence in Great Britain

    International Nuclear Information System (INIS)

    Richardson, Sylvia; Monfort, Christine; Green, Martyn; Muirhead, Colin; Draper, Gerald

    1995-01-01

    This paper describes an analysis of the geographical variation of childhood leukaemia incidence in Great Britain over a 15 year period in relation to natural radiation (gamma and radon). Data at the level of the 459 district level local authorities in England, Wales and regional districts in Scotland are analysed in two complementary ways: first, by Poisson regressions with the inclusion of environmental covariates and a smooth spatial structure; secondly, by a hierarchical Bayesian model in which extra-Poisson variability is modelled explicitly in terms of spatial and non-spatial components. From this analysis, we deduce a strong indication that a main part of the variability is accounted for by a local neighbourhood 'clustering' structure. This structure is furthermore relatively stable over the 15 year period for the lymphocytic leukaemias which make up the majority of observed cases. We found no evidence of a positive association of childhood leukaemia incidence with outdoor or indoor gamma radiation levels. There is no consistent evidence of any association with radon levels. Indeed, in the Poisson regressions, a significant positive association was only observed for one 5-year period, a result which is not compatible with a stable environmental effect. Moreover, this positive association became clearly non-significant when over-dispersion relative to the Poisson distribution was taken into account. (author)

  9. Seasonal Variation in Solar Ultra Violet Radiation and Early Mortality in Extremely Preterm Infants.

    Science.gov (United States)

    Salas, Ariel A; Smith, Kelly A; Rodgers, Mackenzie D; Phillips, Vivien; Ambalavanan, Namasivayam

    2015-11-01

    Vitamin D production during pregnancy promotes fetal lung development, a major determinant of infant survival after preterm birth. Because vitamin D synthesis in humans is regulated by solar ultraviolet B (UVB) radiation, we hypothesized that seasonal variation in solar UVB doses during fetal development would be associated with variation in neonatal mortality rates. This cohort study included infants born alive with gestational age (GA) between 23 and 28 weeks gestation admitted to a neonatal unit between 1996 and 2010. Three infant cohort groups were defined according to increasing intensities of solar UVB doses at 17 and 22 weeks gestation. The primary outcome was death during the first 28 days after birth. Outcome data of 2,319 infants were analyzed. Mean birth weight was 830 ± 230 g and median gestational age was 26 weeks. Mortality rates were significantly different across groups (p = 0.04). High-intensity solar UVB doses were associated with lower mortality when compared with normal intensity solar UVB doses (hazard ratio: 0.70; 95% confidence interval: 0.54-0.91; p = 0.01). High-intensity solar UVB doses during fetal development seem to be associated with risk reduction of early mortality in preterm infants. Prospective studies are needed to validate these preliminary findings. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  10. Polyglutamine variation in a flowering time protein correlates with island age in a Hawaiian plant radiation

    Directory of Open Access Journals (Sweden)

    Laakkonen Liisa

    2007-07-01

    Full Text Available Abstract Background A controversial topic in evolutionary developmental biology is whether morphological diversification in natural populations can be driven by expansions and contractions of amino acid repeats in proteins. To promote adaptation, selection on protein length variation must overcome deleterious effects of multiple correlated traits (pleiotropy. Thus far, systems that demonstrate this capacity include only ancient or artificial morphological diversifications. The Hawaiian Islands, with their linear geological sequence, present a unique environment to study recent, natural radiations. We have focused our research on the Hawaiian endemic mints (Lamiaceae, a large and diverse lineage with paradoxically low genetic variation, in order to test whether a direct relationship between coding-sequence repeat diversity and morphological change can be observed in an actively evolving system. Results Here we show that in the Hawaiian mints, extensive polyglutamine (CAG codon repeat polymorphism within a homolog of the pleiotropic flowering time protein and abscisic acid receptor FCA tracks the natural environmental cline of the island chain, consequent with island age, across a period of 5 million years. CAG expansions, perhaps following their natural tendency to elongate, are more frequent in colonists of recently-formed, nutrient-rich islands than in their forebears on older, nutrient-poor islands. Values for several quantitative morphological variables related to reproductive investment, known from Arabidopsis fca mutant studies, weakly though positively correlate with increasing glutamine tract length. Together with protein modeling of FCA, which indicates that longer polyglutamine tracts could induce suboptimally mobile functional domains, we suggest that CAG expansions may form slightly deleterious alleles (with respect to protein function that become fixed in founder populations. Conclusion In the Hawaiian mint FCA system, we infer that

  11. New developments of belt conveyor systems; Inclined belt systems, vertical pipe elevators, vibration belts, oscillating tubes

    Energy Technology Data Exchange (ETDEWEB)

    Bahke, E.A. (Universitaet Karlsruhe, Karlsruhe (Germany, F.R.). Inst. fuer Foerdertechnik)

    1991-03-01

    Factors that have influenced the design of belt conveyor systems are discussed - these include strength and shaping. Belt conveyor systems for inclined, steep-angle and vertical conveying are described and comparison made between cable belt and steel cord belt conveyors used in coal mines. Hose-belt or tube conveyors such as are used in the PWH/Conti-Rollgurt Conveyor System for feeding boilers in German coal fired power stations are mentioned and advantages of the pipe-belt conveyor for vertical transport discussed. Design of the vibratory conveyor for transporting solids upwards by pulses is described. 29 refs., 19 figs., 2 tabs.

  12. Effect of Different Solar Radiation Data Sources on the Variation of Techno-Economic Feasibility of PV Power System

    Science.gov (United States)

    Alghoul, M. A.; Ali, Amer; Kannanaikal, F. V.; Amin, N.; Aljaafar, A. A.; Kadhim, Mohammed; Sopian, K.

    2017-11-01

    The aim of this study is to evaluate the variation in techno-economic feasibility of PV power system under different data sources of solar radiation. HOMER simulation tool is used to predict the techno-economic feasibility parameters of PV power system in Baghdad city, Iraq located at (33.3128° N, 44.3615° E) as a case study. Four data sources of solar radiation, different annual capacity shortages percentage (0, 2.5, 5, and 7.5), and wide range of daily load profile (10-100 kWh/day) are implemented. The analyzed parameters of the techno-economic feasibility are COE (/kWh), PV array power capacity (kW), PV electrical production (kWh/year), No. of batteries and battery lifetime (year). The main results of the study revealed the followings: (1) solar radiation from different data sources caused observed to significant variation in the values of the techno-economic feasibility parameters; therefore, careful attention must be paid to ensure the use of an accurate solar input data; (2) Average solar radiation from different data sources can be recommended as a reasonable input data; (3) it is observed that as the size and of PV power system increases, the effect of different data sources of solar radiation increases and causes significant variation in the values of the techno-economic feasibility parameters.

  13. Spatial variation in near-ground radiation and low temperature. Interactions with forest vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Blennow, K.

    1997-10-01

    Low temperature has a large impact on the survival and distribution of plants. Interactive effects with high irradiance lead to cold-induced photo inhibition, which may impact on the establishment and growth of tree seedlings. In this thesis, novel approaches are applied for relating the spatial variability in low temperature and irradiance to photosynthetic performance and growth of tree seedlings, and for modelling the micro- and local-scale spatial variations in low temperature for heterogeneous terrain. The methodologies include the development and use of a digital image analysis system for hemispherical photographs, the use of Geographic Information Systems (GIS) and statistical methods, field data acquisition of meteorological elements, plant structure, growth and photosynthetic performance. Temperature and amounts of intercepted direct radiant energy for seedlings on clear days (IDRE) were related to chlorophyll a fluorescence, and the dry weight of seedlings. The combination of increased IDRE with reduced minimum temperatures resulted in persistent and strong photo inhibition as the season progressed, with likely implications for the establishment of tree seedlings at forest edges, and within shelter wood. For models of spatial distribution of low air temperature, the sky view factor was used to parameterize the radiative cooling, whilst drainage, ponding and stagnation of cold air, and thermal properties of the ground were all considered. The models hint at which scales and processes govern the development of spatial variations in low temperature for the construction of corresponding mechanistic models. The methodology is well suited for detecting areas that will be frost prone after clearing of forest and for comparing the magnitudes of impacts on low air temperature of forest management practices, such as shelter wood and soil preparation. The results can be used to formulate ground rules for use in practical forestry 141 refs, 5 figs, 1 tab

  14. 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.

  15. Decadal variations in estimated surface solar radiation over Switzerland since the late 19th century

    Directory of Open Access Journals (Sweden)

    A. Sanchez-Lorenzo

    2012-09-01

    Full Text Available Our knowledge on trends in surface solar radiation (SSR involves uncertainties due to the scarcity of long-term time series of SSR, especially with records before the second half of the 20th century. Here we study the trends of all-sky SSR from 1885 to 2010 in Switzerland, which have been estimated using a homogenous dataset of sunshine duration series. This variable is shown to be a useful proxy data of all-sky SSR, which can help to solve some of the current open issues in the dimming/brightening phenomenon. All-sky SSR has been fairly stable with little variations in the first half of the 20th century, unlike the second half of the 20th century that is characterized also in Switzerland by a dimming from the 1950s to the 1980s and a subsequent brightening. Cloud cover changes seem to explain the major part of the decadal variability observed in all-sky SSR, at least from 1885 to the 1970s; at this point, a discrepancy in the sign of the trend is visible in the all-sky SSR and cloud cover series from the 1970s to the present. Finally, an attempt to estimate SSR series for clear-sky conditions, based also on sunshine duration records since the 1930s, has been made for the first time. The mean clear-sky SSR series shows no relevant changes between the 1930s to the 1950s, then a decrease, smaller than the observed in the all-sky SSR, from the 1960s to 1970s, and ends with a strong increase from the 1980s up to the present. During the three decades from 1981 to 2010 the estimated clear-sky SSR trends reported in this study are in line with previous findings over Switzerland based on direct radiative flux measurements. Moreover, the signal of the El Chichón and Pinatubo volcanic eruption visible in the estimated clear-sky SSR records further demonstrates the potential to infer aerosol-induced radiation changes from sunshine duration observations.

  16. Excited meson radiative transitions from lattice QCD using variationally optimized operators

    Energy Technology Data Exchange (ETDEWEB)

    Shultz, Christian J. [Old Dominion Univ., Norfolk, VA (United States); Dudek, Jozef J. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-06-02

    We explore the use of 'optimized' operators, designed to interpolate only a single meson eigenstate, in three-point correlation functions with a vector-current insertion. These operators are constructed as linear combinations in a large basis of meson interpolating fields using a variational analysis of matrices of two-point correlation functions. After performing such a determination at both zero and non-zero momentum, we compute three-point functions and are able to study radiative transition matrix elements featuring excited state mesons. The required two- and three-point correlation functions are efficiently computed using the distillation framework in which there is a factorization between quark propagation and operator construction, allowing for a large number of meson operators of definite momentum to be considered. We illustrate the method with a calculation using anisotopic lattices having three flavors of dynamical quark all tuned to the physical strange quark mass, considering form-factors and transitions of pseudoscalar and vector meson excitations. In conclusion, the dependence on photon virtuality for a number of form-factors and transitions is extracted and some discussion of excited-state phenomenology is presented.

  17. Mixed Total Variation and L1 Regularization Method for Optical Tomography Based on Radiative Transfer Equation

    Directory of Open Access Journals (Sweden)

    Jinping Tang

    2017-01-01

    Full Text Available Optical tomography is an emerging and important molecular imaging modality. The aim of optical tomography is to reconstruct optical properties of human tissues. In this paper, we focus on reconstructing the absorption coefficient based on the radiative transfer equation (RTE. It is an ill-posed parameter identification problem. Regularization methods have been broadly applied to reconstruct the optical coefficients, such as the total variation (TV regularization and the L1 regularization. In order to better reconstruct the piecewise constant and sparse coefficient distributions, TV and L1 norms are combined as the regularization. The forward problem is discretized with the discontinuous Galerkin method on the spatial space and the finite element method on the angular space. The minimization problem is solved by a Jacobian-based Levenberg-Marquardt type method which is equipped with a split Bregman algorithms for the L1 regularization. We use the adjoint method to compute the Jacobian matrix which dramatically improves the computation efficiency. By comparing with the other imaging reconstruction methods based on TV and L1 regularizations, the simulation results show the validity and efficiency of the proposed method.

  18. Changes in radiation dose with variations in human anatomy: moderately and severely obese adults.

    Science.gov (United States)

    Clark, Landon D; Stabin, Michael G; Fernald, Michael J; Brill, Aaron B

    2010-06-01

    The phantoms used in standardized dose assessment are based on a median (i.e., 50th percentile) individual of a large population, for example, adult males or females or children of a particular age. Here we describe phantoms that model instead the influence of obesity on specific absorbed fractions (SAFs) and dose factors in adults. The literature was reviewed to evaluate how individual organ sizes change with variations in body weight in mildly and severely obese adult men and women. On the basis of the literature evaluation, changes were made to our deformable reference adult male and female total-body models. Monte Carlo simulations of radiation transport were performed. SAFs for photons were generated for mildly and severely obese adults, and comparisons were made to the reference (50th) percentile SAF values. SAFs studied between the obese phantoms and the 50th percentile reference phantoms were not significantly different from the reference 50th percentile individual, with the exception of intestines irradiating some abdominal organs, because of an increase in separation between folds caused by an increase in mesenteric adipose deposits. Some low-energy values for certain organ pairs were different, possibly due only to the statistical variability of the data at these low energies. The effect of obesity on dose calculations for internal emitters is minor and may be neglected in the routine use of standardized dose estimates.

  19. Temperature variation of non-radiative recombination rate in a-Si:H films

    Energy Technology Data Exchange (ETDEWEB)

    Ogihara, C. [Department of Applied Science, Yamaguchi University, Ube 755-8611 (Japan); Morigaki, K. [Department of Electrical and Digital-System Engineering, Hiroshima Institute of Technology, Miyake, Saeki-ku, Hiroshima 731-5193 (Japan); resent address: C-305, 2-12 Wakabadai, Inagi, Tokyo 206-0824 (Japan)

    2012-12-15

    Temperature variation of the recombination rates has been investigated for the electron-hole pairs responsible for defect PL in a defective a-Si:H film as grown. The results are compared with those obtained for a high-quality a-Si:H film after illumination. The results of the nonradiative recombination rate are fitted by a theoretical prediction for the case of strong electron-phonon coupling in the case of the defective a-Si:H film similarly to the case of the illuminated high-quality a-Si:H film. Difference between the frequency of the phonon associated with the non-radiative recombination process in the defective a-Si:H film and that in the illuminated highquality a-Si:H film is discussed by considering the influence of the amorphous network in the a-Si:H films affected by the preparation conditions and the nature of the native and photo-created defects. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Variations in Medicare Reimbursement in Radiation Oncology: An Analysis of the Medicare Provider Utilization and Payment Data Set

    International Nuclear Information System (INIS)

    Vu, Charles C.; Lanni, Thomas B.; Robertson, John M.

    2016-01-01

    Purpose: The purposes of this study were to summarize recently published data on Medicare reimbursement to individual radiation oncologists and to identify the causes of variation in Medicare reimbursement in radiation oncology. Methods and Materials: The Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File (POSPUF), which details nearly all services provided by radiation oncologists in 2012, was used for this study. The data were filtered and analyzed by physician and by billing code. Statistical analysis was performed to identify differences in reimbursements based on sex, rurality, billing of technical services, or location in a certificate of need (CON) state. Results: There were 4135 radiation oncologists who received a total of $1,499,625,803 in payments from Medicare in 2012. Seventy-five percent of radiation oncologists were male. The median reimbursement was $146,453. The code with the highest total reimbursement was 77418 (radiation treatment delivery intensity modulated radiation therapy [IMRT]). The most commonly billed evaluation and management (E/M) code for new visits was 99205 (49%). The most commonly billed E/M code for established visits was 99213 (54%). Forty percent of providers billed none of their new office visits using 99205 (the highest E/M billing code), whereas 34% of providers billed all of their new office visits using 99205. For the 1510 radiation oncologists (37%) who billed technical services, median Medicare reimbursement was $606,008, compared with $93,921 for all other radiation oncologists (P<.001). On multivariate analysis, technical services billing (P<.001), male sex (P<.001), and rural location (P=.007) were predictive of higher Medicare reimbursement. Conclusions: The billing of technical services, with their high capital and labor overhead requirements, limits any comparison in reimbursement between individual radiation oncologists or between radiation oncologists and other

  1. Variations in Medicare Reimbursement in Radiation Oncology: An Analysis of the Medicare Provider Utilization and Payment Data Set.

    Science.gov (United States)

    Vu, Charles C; Lanni, Thomas B; Robertson, John M

    2016-04-01

    The purposes of this study were to summarize recently published data on Medicare reimbursement to individual radiation oncologists and to identify the causes of variation in Medicare reimbursement in radiation oncology. The Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File (POSPUF), which details nearly all services provided by radiation oncologists in 2012, was used for this study. The data were filtered and analyzed by physician and by billing code. Statistical analysis was performed to identify differences in reimbursements based on sex, rurality, billing of technical services, or location in a certificate of need (CON) state. There were 4135 radiation oncologists who received a total of $1,499,625,803 in payments from Medicare in 2012. Seventy-five percent of radiation oncologists were male. The median reimbursement was $146,453. The code with the highest total reimbursement was 77418 (radiation treatment delivery intensity modulated radiation therapy [IMRT]). The most commonly billed evaluation and management (E/M) code for new visits was 99205 (49%). The most commonly billed E/M code for established visits was 99213 (54%). Forty percent of providers billed none of their new office visits using 99205 (the highest E/M billing code), whereas 34% of providers billed all of their new office visits using 99205. For the 1510 radiation oncologists (37%) who billed technical services, median Medicare reimbursement was $606,008, compared with $93,921 for all other radiation oncologists (Preimbursement. The billing of technical services, with their high capital and labor overhead requirements, limits any comparison in reimbursement between individual radiation oncologists or between radiation oncologists and other specialists. Male sex and rural practice location are independent predictors of higher total Medicare reimbursements. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Variations in Medicare Reimbursement in Radiation Oncology: An Analysis of the Medicare Provider Utilization and Payment Data Set

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Charles C.; Lanni, Thomas B.; Robertson, John M., E-mail: JRobertson@beaumont.edu

    2016-04-01

    Purpose: The purposes of this study were to summarize recently published data on Medicare reimbursement to individual radiation oncologists and to identify the causes of variation in Medicare reimbursement in radiation oncology. Methods and Materials: The Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File (POSPUF), which details nearly all services provided by radiation oncologists in 2012, was used for this study. The data were filtered and analyzed by physician and by billing code. Statistical analysis was performed to identify differences in reimbursements based on sex, rurality, billing of technical services, or location in a certificate of need (CON) state. Results: There were 4135 radiation oncologists who received a total of $1,499,625,803 in payments from Medicare in 2012. Seventy-five percent of radiation oncologists were male. The median reimbursement was $146,453. The code with the highest total reimbursement was 77418 (radiation treatment delivery intensity modulated radiation therapy [IMRT]). The most commonly billed evaluation and management (E/M) code for new visits was 99205 (49%). The most commonly billed E/M code for established visits was 99213 (54%). Forty percent of providers billed none of their new office visits using 99205 (the highest E/M billing code), whereas 34% of providers billed all of their new office visits using 99205. For the 1510 radiation oncologists (37%) who billed technical services, median Medicare reimbursement was $606,008, compared with $93,921 for all other radiation oncologists (P<.001). On multivariate analysis, technical services billing (P<.001), male sex (P<.001), and rural location (P=.007) were predictive of higher Medicare reimbursement. Conclusions: The billing of technical services, with their high capital and labor overhead requirements, limits any comparison in reimbursement between individual radiation oncologists or between radiation oncologists and other

  3. A mathematical correlation between variations in solar radiation parameters. 2. Global radiation, air temperature and specific humidity

    International Nuclear Information System (INIS)

    Njau, E.C.

    1988-06-01

    We derive from first principles, an equation which expresses global radiation as a function of specific humidity and air temperature at screen height. The practical validity of this equation is tested by using humidity, air temperature and global radiation data from Tanzania. It is shown that global radiation values calculated on the basis of the derived equation agree with measured radiation values to within ± 8% as long as the prevalent (horizontal) winds are either calm or light. It is noted that the equation is equally valid at times of strong horizontal winds provided that the temperature and humidity measuring site is sufficiently shielded from the winds. This implies that meteorological stations that are (for some unavoidable reasons) unable to stock pyranometers can still procure reasonable estimates of local global radiation as long as they can, at least, stock the relatively cheaper barometers and wet- and dry-bulb psychrometers. (author). 12 refs, 1 fig., 4 tabs

  4. A Variationally Formulated Problem of the Stationary Heat Conduction in a Plate with Radiation Reduction Factor Increased under Temperature

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2016-01-01

    dependence of the absorption factor on the local intensity of this radiation. Furthermore, it can be a significant dependence of this factor on the local value of the material temperature, reflecting the above-mentioned relationship between the absorption of electromagnetic wave energy and the excitation of material microparticles. This process can be described by Boltzmann distribution function that comprises the energy to activate microparticles and the local value of temperature.This paper presents a variational formulation of the nonlinear problem of stationary heat conduction in a plate for the case when the radiation reduction factor in relation to the Bouguer law depends on the local temperature. This formulation includes a functional that can have several fixed points corresponding to different steady states of the plate temperature. Analysis of the properties of this functional enabled us to identify the stationary points, which correspond to the realized temperature distribution in the plate.

  5. Deconstructing the conveyor belt.

    Science.gov (United States)

    Lozier, M Susan

    2010-06-18

    For the past several decades, oceanographers have embraced the dominant paradigm that the ocean's meridional overturning circulation operates like a conveyor belt, transporting cold waters equatorward at depth and warm waters poleward at the surface. Within this paradigm, the conveyor, driven by changes in deepwater production at high latitudes, moves deep waters and their attendant properties continuously along western boundary currents and returns surface waters unimpeded to deepwater formation sites. A number of studies conducted over the past few years have challenged this paradigm by revealing the vital role of the ocean's eddy and wind fields in establishing the structure and variability of the ocean's overturning. Here, we review those studies and discuss how they have collectively changed our view of the simple conveyor-belt model.

  6. Flow of Energy through the Inner Magnetosphere during the March 17, 2015 solar storm as observed by the Van Allen Probes Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE)

    Science.gov (United States)

    Manweiler, J. W.; Madanian, H.; Gerrard, A. J.; Patterson, J. D.; Mitchell, D. G.; Lanzerotti, L. J.

    2017-12-01

    On March 17, 2015, a large solar storm impacted the Earth's magnetosphere with a maximum negative Dst of -232 nT. We report on the temporal and spatial evolution of the proton energetic particle distributions in phase space during this storm, as measured by the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instrument on board each of the Van Allen Probes. We characterize the distribution prior to onset of the storm to provide a definition of quiet time conditions. We then show how the distribution evolves during the storm noting key changes of the distribution as a function of L and MLT and showing how the pitch angle distributions change throughout the storm. These observations displayed a number of interesting features of the storm including high beta plasma conditions and multiple injections of protons into the inner magnetosphere. We present the radial changes of the distribution at storm onset and following the evolution of the distribution during storm recovery. We compare observations of the East/West asymmetry in the proton distribution before versus after onset using both Van Allen Probes A and B spacecraft observations. Finally, we note interesting changes in the distribution showing an anomalous dropout in mid-energies of the distribution and observe an outward radial propagation of this dropout during recovery.

  7. Variations observed in the respiratory activity of potato tubers (Solanum tuberosum L.) after a treatment with gamma radiation

    International Nuclear Information System (INIS)

    Mazon Matanzo, M. P.; Fernandez Gonzalez, J.

    1976-01-01

    The present work studies the variations in the respiratory activity of irradiated and IPC treated potato tubers during a storage period of five months. By immediate effect of gamma radiation we can observe an increase in the oxygen consumption of the parenchyma in relation with the control tubers, such increase persists even fours months after gamma radiation. The respiratory activity is reduced in the IPC treated tubers. In the tissues cultivated in vitro the respiratory activity increases at the end of the cultivation period, not only in the control tissues but also in the irradiated ones, though this increase is greater in the control tissues. (Author) 15 refs

  8. Investigation of the effect of ionizing radiation on gene expression variation by the 'DNA chips': feasibility of a biological dosimeter

    International Nuclear Information System (INIS)

    Gruel, G.

    2005-01-01

    After having described the different biological effects of ionizing radiation and the different approaches to biological dosimetry, and introduced 'DNA chips' or DNA micro-arrays, the author reports the characterization of gene expression variations in the response of cells to a gamma irradiation. Both main aspects of the use DNA chips are investigated: fundamental research and diagnosis. This research thesis thus proposes an analysis of the effect of ionizing radiation using DNA chips, notably by comparing gene expression modifications measured in mouse irradiated lung, heart and kidney. It reports a feasibility study of bio-dosimeter based on expression profiles

  9. Variations observed in the respiratory activity of potato tubers (Solanum tuberosum L.) after a treatment with gamma radiation

    International Nuclear Information System (INIS)

    Mazon Matanzo, M.P.; Fernandez Gonzalez, J.

    1976-01-01

    The variations in the respiratory activity of irradiated and IPC treated potato tubers during a storage period of five months have been studied. By immediate effect of gamma radiation, an increase in the oxigen consumption of the parenchyma in relation with the control tubers has been observed. Such increase persits even four months after gamma radiation. The respiratory activity is reduced in the IPC treated tubers. In the tissues cultivated ''in vitro'' the respiratory activity increases at the end of the cultivation period, not only in the control tissues but also in the irradiated ones, though this increase is greater in the control tissues.(author) [es

  10. Variation in well-head gamma radiation levels at the Nigerian ...

    African Journals Online (AJOL)

    It was generally observed that the level of radiation around the well heads is less than 20x 10-12mSv/hr, which is in agreement with the International Atomic Energy Agency\\'s standard on ionizing radiation background level. Keywords: Radiation, crude oil, radionuclide, contaminant, exposure. Nigerian Journal of Physics ...

  11. Research on Ship-Radiated Noise Denoising Using Secondary Variational Mode Decomposition and Correlation Coefficient.

    Science.gov (United States)

    Li, Yuxing; Li, Yaan; Chen, Xiao; Yu, Jing

    2017-12-26

    As the sound signal of ships obtained by sensors contains other many significant characteristics of ships and called ship-radiated noise (SN), research into a denoising algorithm and its application has obtained great significance. Using the advantage of variational mode decomposition (VMD) combined with the correlation coefficient for denoising, a hybrid secondary denoising algorithm is proposed using secondary VMD combined with a correlation coefficient (CC). First, different kinds of simulation signals are decomposed into several bandwidth-limited intrinsic mode functions (IMFs) using VMD, where the decomposition number by VMD is equal to the number by empirical mode decomposition (EMD); then, the CCs between the IMFs and the simulation signal are calculated respectively. The noise IMFs are identified by the CC threshold and the rest of the IMFs are reconstructed in order to realize the first denoising process. Finally, secondary denoising of the simulation signal can be accomplished by repeating the above steps of decomposition, screening and reconstruction. The final denoising result is determined according to the CC threshold. The denoising effect is compared under the different signal-to-noise ratio and the time of decomposition by VMD. Experimental results show the validity of the proposed denoising algorithm using secondary VMD (2VMD) combined with CC compared to EMD denoising, ensemble EMD (EEMD) denoising, VMD denoising and cubic VMD (3VMD) denoising, as well as two denoising algorithms presented recently. The proposed denoising algorithm is applied to feature extraction and classification for SN signals, which can effectively improve the recognition rate of different kinds of ships.

  12. Research on Ship-Radiated Noise Denoising Using Secondary Variational Mode Decomposition and Correlation Coefficient

    Directory of Open Access Journals (Sweden)

    Yuxing Li

    2017-12-01

    Full Text Available As the sound signal of ships obtained by sensors contains other many significant characteristics of ships and called ship-radiated noise (SN, research into a denoising algorithm and its application has obtained great significance. Using the advantage of variational mode decomposition (VMD combined with the correlation coefficient for denoising, a hybrid secondary denoising algorithm is proposed using secondary VMD combined with a correlation coefficient (CC. First, different kinds of simulation signals are decomposed into several bandwidth-limited intrinsic mode functions (IMFs using VMD, where the decomposition number by VMD is equal to the number by empirical mode decomposition (EMD; then, the CCs between the IMFs and the simulation signal are calculated respectively. The noise IMFs are identified by the CC threshold and the rest of the IMFs are reconstructed in order to realize the first denoising process. Finally, secondary denoising of the simulation signal can be accomplished by repeating the above steps of decomposition, screening and reconstruction. The final denoising result is determined according to the CC threshold. The denoising effect is compared under the different signal-to-noise ratio and the time of decomposition by VMD. Experimental results show the validity of the proposed denoising algorithm using secondary VMD (2VMD combined with CC compared to EMD denoising, ensemble EMD (EEMD denoising, VMD denoising and cubic VMD (3VMD denoising, as well as two denoising algorithms presented recently. The proposed denoising algorithm is applied to feature extraction and classification for SN signals, which can effectively improve the recognition rate of different kinds of ships.

  13. How do air ions reflect variations in ionising radiation in the lower atmosphere in a boreal forest?

    Directory of Open Access Journals (Sweden)

    X. Chen

    2016-11-01

    Full Text Available Most of the ion production in the atmosphere is attributed to ionising radiation. In the lower atmosphere, ionising radiation consists mainly of the decay emissions of radon and its progeny, gamma radiation of the terrestrial origin as well as photons and elementary particles of cosmic radiation. These types of radiation produce ion pairs via the ionisation of nitrogen and oxygen as well as trace species in the atmosphere, the rate of which is defined as the ionising capacity. Larger air ions are produced out of the initial charge carriers by processes such as clustering or attachment to pre-existing aerosol particles. This study aimed (1 to identify the key factors responsible for the variability in ionising radiation and in the observed air ion concentrations, (2 to reveal the linkage between them and (3 to provide an in-depth analysis into the effects of ionising radiation on air ion formation, based on measurement data collected during 2003–2006 from a boreal forest site in southern Finland. In general, gamma radiation dominated the ion production in the lower atmosphere. Variations in the ionising capacity came from mixing layer dynamics, soil type and moisture content, meteorological conditions, long-distance transportation, snow cover attenuation and precipitation. Slightly similar diurnal patterns to variations in the ionising capacity were observed in air ion concentrations of the cluster size (0.8–1.7 nm in mobility diameters. However, features observed in the 0.8–1 nm ion concentration were in good connection to variations of the ionising capacity. Further, by carefully constraining perturbing variables, a strong dependency of the cluster ion concentration on the ionising capacity was identified, proving the functionality of ionising radiation in air ion production in the lower atmosphere. This relationship, however, was only clearly observed on new particle formation (NPF days, possibly indicating that charges after

  14. 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.

  15. [Effects of silicon supply on diurnal variations of physiological properties at rice heading stage under elevated UV-B radiation].

    Science.gov (United States)

    Wu, Lei; Lou, Yun-sheng; Meng, Yan; Wang, Wei-qing; Cui, He-yang

    2015-01-01

    A pot experiment was conducted to investigate the effects of silicon (Si) supply on diurnal variations of photosynthesis and transpiration-related physiological parameters at rice heading stage under elevated UV-B radiation. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B. (ambient, A) and elevated UV-B (elevated by 20%, E), and four Si supply levels, i.e. Sio (control, 0 kg SiO2 . hm-2), Si, (sodium silicate, 100 kg SiO2 . hm-2), Si2 (sodium silicate, 200 kg SiO2 . hm2), Si3 (slag fertilizer, 200 kg SiO2 . hm-2). The results showed that, compared with ambient UV-B radiation, elevated UV-B radiation decreased the net photosynthesis rate (Pn) , intercellular CO2 concentration (Ci), transpiration rate (Tr), stomatal conductivity (gs) and water use efficiency (WUE) by 11.3%, 5.5%, 10.4%, 20.3% and 6.3%, respectively, in the treatment without Si supply (Si, level), and decreased the above parameters by 3.8%-5.5%, 0.7%-4.8%, 4.0%-8.7%, 7.4%-20.2% and 0.7%-5.9% in the treatments with Si supply (Si1, Si2 and Si3 levels) , respectively. Namely, elevated UV-B radiation decreased the photosynthesis and transpiration-related physiological parameters, but silicon supply could obviously mitigate the depressive effects of elevated UV-B radiation. Under elevated UV-B radiation, compared with control (Si0 level), silicon supply increased Pn, Ci, gs and WUE by 16.9%-28.0%, 3.5%-14.3%, 16.8% - 38.7% and 29.0% - 51.2%, respectively, but decreased Tr by 1.9% - 10.8% in the treatments with Si supply (Si1 , Si2 and Si3 levels). That is, silicon supply could mitigate the depressive effects of elevated UV-B radiation through significantly increasingnP., CigsgK and WUE, but decreasing T,. However, the difference existed in ameliorating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among the treatments of silicon supply, with the sequence of Si3>Si2>1i >Si0. This study suggested that fertilizing slag was

  16. Influence of cloud fraction and snow cover to the variation of surface UV radiation at King Sejong station, Antarctica

    Science.gov (United States)

    Lee, Yun Gon; Koo, Ja-Ho; Kim, Jhoon

    2015-10-01

    This study investigated how cloud fraction and snow cover affect the variation of surface ultraviolet (UV) radiation by using surface Erythemal UV (EUV) and Near UV (NUV) observed at the King Sejong Station, Antarctica. First the Radiative Amplification Factor (RAF), the relative change of surface EUV according to the total-column ozone amount, is compared for different cloud fractions and solar zenith angles (SZAs). Generally, all cloudy conditions show that the increase of RAF as SZA becomes larger, showing the larger effects of vertical columnar ozone. For given SZA cases, the EUV transmission through mean cloud layer gradually decreases as cloud fraction increases, but sometimes the maximum of surface EUV appears under partly cloudy conditions. The high surface EUV transmittance under broken cloud conditions seems due to the re-radiation of scattered EUV by cloud particles. NUV transmission through mean cloud layer also decreases as cloud amount increases but the sensitivity to the cloud fraction is larger than EUV. Both EUV and NUV radiations at the surface are also enhanced by the snow cover, and their enhancement becomes higher as SZA increases implying the diurnal variation of surface albedo. This effect of snow cover seems large under the overcast sky because of the stronger interaction between snow surface and cloudy sky.

  17. Storm-time variation of radiative cooling by Nitric Oxide as observed by TIMED-SABER and GUVI

    Science.gov (United States)

    Sunil Krishna, M. V.; Bharti, G.; Bag, T.

    2017-12-01

    The variation of O/N2 and nitric oxide radiative emission flux exiting thermosphere have been studied over northern hemisphere during the super-storm event of November 7-12, 2004. The data have been obtained from GUVI and SABER onboard the NASA's TIMED satellite. The NO radiative flux is observed to show an anti-correlation with O/N2 on a global scale. Both NO radiative flux and O/N2 ratio show equatorward motion with maximum penetration in western longitude sectors. A local variation of O, O2 and N2 densities have been calculated by using NRLMSISE-00 model over a mid-latitude location (55oN,180oE). On a local scale, model calculated O/O2 and O/N2 ratios are found to follow the observations made by GUVI. The SABER retrieved NO cooling rate (CR) at a local site suggests an enhancement during the storm period with the peak emission rate closely correlated to the progression of the storm. The peak emission altitude of NO CR moves upward during the main phase of the storm. The NO abundance has been calculated by using cooling rate and NOEM model. Both these suggest huge increase in NO density during the storm which is required to account the changes in NO radiative flux.

  18. Belt for picking up liquids

    Energy Technology Data Exchange (ETDEWEB)

    Sewell, R B.H.; Nelson, S P

    1973-05-18

    This belt for picking up liquids consists of a layer of strong material, e.g., coarse cloth, sewed on at least one layer of absorbing material, e.g., sponge cloth, the stitching being disposed along chevrons with their apexes along the central axis of the belt; the edges do not contain any other marks. This arrangement facilitates the expulsion of the absorbed liquid when the belt passes between compression rollers.

  19. Study of gamma radiation induced damages and variation of oxygen enhancement ratio with radiation dose using Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Nairy, R.K.; Yerol Narayana; Bhat, N.N.; Anjaria, K.B.; Sreedevi, B.; Sapra, B.K.

    2014-01-01

    In the present study, an attempt has been made to quantify Oxygen Enhancement Ratio (OER) and variation of OER as a function of dose with experimental and theoretical formulations using Saccharomyces cerevisiae D7, X2180 and rad 52. The study confirms that, the variation of OER with dose depends upon type of cell and repair proficiency of cells. A theoretical model has been formulated to estimate OER values. With the help of this model, OER value for any dose can be calculated in the exponential region of the survival curve without actually extending the experiment in that dose region. (author)

  20. Synchrotron Radiation X-Ray Fluorescence nanoanalyses of the metallome of a ~3.3 Ga-old microbial biofilm from the Barberton greenstone belt, South Africa.

    Science.gov (United States)

    Hubert, A.; Lemelle, L.; Salome, M.; Cloetens, P.; Westall, F.; Simionovici, A.

    2012-04-01

    Combining in situ nanometer-scale techniques on the fossilized Josefsdal Chert Microbial Biofilm (JCMB) reveals a distinct vertical structural and compositional organisation: the lower part is calcified as aragonite, while the upper non-calcified kerogenous layer is characterised by up to 1% sulphur [1]. The in situ analysis of all the metals as a group represents a useful microbial fingerprint [2] and we will continue to explore it. Synchrotron Radiation X-Ray Fluorescence maps of high spatial resolution (Conference Proceedings, 1221, 131-138. 4. Bleuet P., et al., 2008. App. Phys. Lett., 92, 213111-1-3. 5. Golosio B., et al., 2003. Appl. Phys., 94, 145-157. 6. M. Haschke, 2003. PhD dissertation, T.U. Berlin. 7. Simionovici A. S., et al., 2010. Proceedings of the Meteoritical Society Conference, N.Y., USA. 8. Solé V.A., et al., 2006, Elsevier, 62, 63-68.

  1. Electromagnetic Radiation : Variational Methods, Waveguides and Accelerators Including seminal papers of Julian Schwinger

    CERN Document Server

    Milton, Kimball A

    2006-01-01

    This is a graduate level textbook on the theory of electromagnetic radiation and its application to waveguides, transmission lines, accelerator physics and synchrotron radiation. It has grown out of lectures and manuscripts by Julian Schwinger prepared during the war at MIT's Radiation Laboratory, updated with material developed by Schwinger at UCLA in the 1970s and 1980s, and by Milton at the University of Oklahoma since 1994. The book includes a great number of straightforward and challenging exercises and problems. It is addressed to students in physics, electrical engineering, and applied mathematics seeking a thorough introduction to electromagnetism with emphasis on radiation theory and its applications.

  2. 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

  3. Spectral variations of UV-A and PAR solar radiation in estuarine waters of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Talaulikar, M.; Suresh, T.; Silveira, N.; Desa, E.; Matondkar, S; Lotlikar, A

    radiation (400 to 700 nm), PAR and ultraviolet radiation in the range 350-400 nm (UV-A) are presented here. The mean PAR values at the surface were 327 W/m sup(2) and reduced to 84 W/m sup(2) at first optical depth, Z sub(90) (m) in water. The first optical...

  4. Variation in the Definition of Clinical Target Volumes for Pelvic Nodal Conformal Radiation Therapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Lawton, Colleen A.F.; Michalski, Jeff; El-Naqa, Issam; Kuban, Deborah; Lee, W. Robert; Rosenthal, Seth A.; Zietman, Anthony; Sandler, Howard; Shipley, William; Ritter, Mark; Valicenti, Richard; Catton, Charles; Roach, Mack; Pisansky, Thomas M.; Seider, Michael

    2009-01-01

    Purpose: We conducted a comparative study of clinical target volume (CTV) definition of pelvic lymph nodes by multiple genitourinary (GU) radiation oncologists looking at the levels of discrepancies amongst this group. Methods and Materials: Pelvic computed tomography (CT) scans from 2 men were distributed to 14 Radiation Therapy Oncology Group GU radiation oncologists with instructions to define CTVs for the iliac and presacral lymph nodes. The CT data with contours were then returned for analysis. In addition, a questionnaire was completed that described the physicians' method for target volume definition. Results: Significant variation in the definition of the iliac and presacral CTVs was seen among the physicians. The minimum, maximum, mean (SD) iliac volumes (mL) were 81.8, 876.6, 337.6 ± 203 for case 1 and 60.3, 627.7, 251.8 ± 159.3 for case 2. The volume of 100% agreement was 30.6 and 17.4 for case 1 and 2 and the volume of the union of all contours was 1,012.0 and 807.4 for case 1 and 2, respectively. The overall agreement was judged to be moderate in both cases (kappa = 0.53 (p < 0.0001) and kappa = 0.48 (p < 0.0001). There was no volume of 100% agreement for either of the two presacral volumes. These variations were confirmed in the responses to the associated questionnaire. Conclusions: Significant disagreement exists in the definition of the CTV for pelvic nodal radiation therapy among GU radiation oncology specialists. A consensus needs to be developed so as to accurately assess the merit and safety of such treatment.

  5. 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.

  6. Radiation Hardened Structured ASIC Platform with Compensation of Delay for Temperature and Voltage Variations for Multiple Redundant Temporal Voting Latch Technology

    Science.gov (United States)

    Ardalan, Sasan (Inventor)

    2018-01-01

    The invention relates to devices and methods of maintaining the current starved delay at a constant value across variations in voltage and temperature to increase the speed of operation of the sequential logic in the radiation hardened ASIC design.

  7. General trend and local variations of neutron resonance cascade gamma-decay radiative strength functions

    International Nuclear Information System (INIS)

    Sukhovoj, A.M.; Furman, W.I.; Khitrov, V.A.; Jovancevic, N.

    2012-01-01

    A new hypothesis on the dependence of the form of the radiative strength functions of electric and magnetic dipole gamma transitions in a heated nucleus on the excited level density was suggested and tested experimentally. For this purpose, the region of possible values of random values of the level density and radiative strength functions which precisely reproduced experimental intensity of two-step cascades for 41 nuclei from 40K to 200Hg was determined. It was obtained that the suggested hypothesis can provide the maximal increase of radiative strength functions values by order of magnitude in comparison with existing notations as a result of collective effects enhancement. This result points to the necessity to take into account this possibility in existing and future models of radiative strength functions

  8. On-conveyor belt determination of ash in coal

    International Nuclear Information System (INIS)

    Sowerby, B.; Lim, C.S.; Abernethy, D.A.; Liu, Y.; Maguire, P.A.

    1997-01-01

    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

  9. Plant trial of an under-belt capacitance and gamma-ray backscatter gauge for on-belt determination of moisture in coal

    International Nuclear Information System (INIS)

    Cutmore, N.G.; Rafter, P.T.; Abernethy, D.A.; Millen, M.J.

    1989-01-01

    A non-contacting under-belt capacitance and gamma-ray backscatter technique has been developed for the on-line measurement of moisture in coal. In this technique, moisture was correlated with radio frequency susceptance and conductance, determined using an under-belt capacitance sensor in which a fringing electric field interrogates a layer of coal on the conveyor belt directly about the sensor. To compensate for variations in the density and thickness of the coal layer, an under-belt gamma-ray backscatter gauge was used to measure an equivalent volume of coal. A plant trial of the technique was conducted at Stockton Borehole Colliery, NSW Australia, where the gauges were installed on the coking coal product conveyor. Product moistures, in the range 7-14%, were determined with r.m.s errors of 0.50 and 0.25 wt% using on-belt and static off-belt gauges, respectively. The difference in the on-belt and off-belt gauge measurement accuracy was attributed to sampling errors in the calibration of the on-belt gauge. 6 refs., 6 figs., 3 tabs

  10. Study of time variation of terrestrial gamma radiation due to depth distribution of soil moisture content

    International Nuclear Information System (INIS)

    Yoshioka, Katsuhiro

    1994-01-01

    An empirical equation was deduced from studies of time variations of terrestrial gamma exposure rate and soil moisture content with depth distribution in the surface layer. It was definitely suggested that the variation of terrestrial gamma exposure rate is most strongly influenced by the change of soil moisture content at 5 cm depth. The seasonal variation with a relative maximum in early autumn and a relative minimum in early spring was clearly obtained in the consequence of long time measurements of terrestrial gamma exposure rate and degree of soil dryness. The diurnal change and phase difference due to the effect of depth were also obtained in the dynamic characteristics of soil moisture content at 3 different depths. From the comparison between measured terrestrial gamma exposure rate and that evaluated from soil moisture content using the empirical equation, it was seen that seasonal variations of the both agreed fairly well as a whole. (author)

  11. Racial Variations in Radiation-Induced Skin Toxicity Severity: Data From a Prospective Cohort Receiving Postmastectomy Radiation

    International Nuclear Information System (INIS)

    Wright, Jean L.; Takita, Cristiane; Reis, Isildinha M.; Zhao, Wei; Lee, Eunkyung; Hu, Jennifer J.

    2014-01-01

    Purpose: Radiation-induced skin toxicity is one of the most symptomatic side effects of postmastectomy radiation therapy (PMRT). We sought to determine whether the severity of acute skin toxicity was greater in black patients in a prospective cohort receiving PMRT and to identify other predictors of more severe skin toxicity. Methods and Materials: We evaluated the first 110 patients in an ongoing prospective study assessing radiation-induced skin toxicity in patients receiving PMRT. We recorded patient demographics, body mass index (BMI), and disease and treatment characteristics. Logistic regression analyses were conducted to evaluate the effect of potential predictors on the risk of skin toxicity. Results: A total of 23.6% respondents self-identified as black, 5.5% as non-Hispanic white, 69.1% as Hispanic white, and 1.8% as other; 57% were postmenopausal, and 70.9% had BMI of >25. Median chest wall dose was 50 Gy, and mastectomy scar dose was 60 Gy. Most patients, 95.5%, were treated with a 0.5-cm bolus throughout treatment. There were no significant differences in patient characteristics in black versus non-black patients. At RT completion, moist desquamation was more common in black patients (73.1% vs 47.6%, respectively, P=.023), in postmenopausal patients (63.5% vs 40.4%, respectively, P=.016), and in those with BMI of ≥25 (60.3% vs 37.5%, respectively, P=.030). On multivariate analysis, the effects of black race (odds ratio [OR] = 7.46, P=.031), BMI ≥25 (OR = 2.95, P=.043) and postmenopausal status (OR = 8.26, P=.004) remained significant risk factors for moist desquamation. Conclusions: In this prospectively followed, racially diverse cohort of breast cancer patients receiving PMRT delivered in a uniform fashion, including the routine use of chest wall boost and bolus, black race, higher BMI, and postmenopausal status emerged as significant predictors of moist desquamation. There was a high frequency of moist desquamation, particularly in those

  12. Racial Variations in Radiation-Induced Skin Toxicity Severity: Data From a Prospective Cohort Receiving Postmastectomy Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Jean L., E-mail: jwrigh71@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Takita, Cristiane [Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, Florida (United States); Reis, Isildinha M. [Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida (United States); Department of Public Health Sciences, University of Miami, Miami, Florida (United States); Zhao, Wei; Lee, Eunkyung [Department of Public Health Sciences, University of Miami, Miami, Florida (United States); Hu, Jennifer J. [Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida (United States); Department of Public Health Sciences, University of Miami, Miami, Florida (United States)

    2014-10-01

    Purpose: Radiation-induced skin toxicity is one of the most symptomatic side effects of postmastectomy radiation therapy (PMRT). We sought to determine whether the severity of acute skin toxicity was greater in black patients in a prospective cohort receiving PMRT and to identify other predictors of more severe skin toxicity. Methods and Materials: We evaluated the first 110 patients in an ongoing prospective study assessing radiation-induced skin toxicity in patients receiving PMRT. We recorded patient demographics, body mass index (BMI), and disease and treatment characteristics. Logistic regression analyses were conducted to evaluate the effect of potential predictors on the risk of skin toxicity. Results: A total of 23.6% respondents self-identified as black, 5.5% as non-Hispanic white, 69.1% as Hispanic white, and 1.8% as other; 57% were postmenopausal, and 70.9% had BMI of >25. Median chest wall dose was 50 Gy, and mastectomy scar dose was 60 Gy. Most patients, 95.5%, were treated with a 0.5-cm bolus throughout treatment. There were no significant differences in patient characteristics in black versus non-black patients. At RT completion, moist desquamation was more common in black patients (73.1% vs 47.6%, respectively, P=.023), in postmenopausal patients (63.5% vs 40.4%, respectively, P=.016), and in those with BMI of ≥25 (60.3% vs 37.5%, respectively, P=.030). On multivariate analysis, the effects of black race (odds ratio [OR] = 7.46, P=.031), BMI ≥25 (OR = 2.95, P=.043) and postmenopausal status (OR = 8.26, P=.004) remained significant risk factors for moist desquamation. Conclusions: In this prospectively followed, racially diverse cohort of breast cancer patients receiving PMRT delivered in a uniform fashion, including the routine use of chest wall boost and bolus, black race, higher BMI, and postmenopausal status emerged as significant predictors of moist desquamation. There was a high frequency of moist desquamation, particularly in those

  13. Study of the variation of radiation dose in function of the radiological techniques used in X-ray diagnosis exams

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Marco A.R., E-mail: marfernandes@fmb.unesp.br [Faculty of Medicine. UNESP, Botucatu (FMB), SP (Brazil); Reis, Charlene O.; Garcia, Paulo L. [Institute of Biosciences of Botucatu. UNESP, Botucatu, SP (Brazil); Nucleate Radiometry Ltd., Aracatuba, SP (Brazil); Lima, Marcelo A.F.; Dalaqua, Fernando L.D. [UNESP, Botucatu, SP (Brazil). Hospital. Radiology Service

    2011-07-01

    This paper values the importance of the implantation of a quality control program in medical x-ray diagnosis services that it seeks mainly to the reduction of the radiation dose applied in the radiology exams, and attempt to the precepts of the Effective Legislation as for the Basic Guidelines of Radiological Protection (law decree MS no. 453 in June 1{sup st} 1998). The study was accomplished Radiology Section of the Medicine Faculty - FMB (UNESP - Botucatu) and it consisted of the accomplishment of measures of the radiation dose applied in the radiological exams, taking as base the x-rays techniques realized by four technicians in radiology the service, using only one x-rays equipment. Was intended analyze the variation of the radiation dose in function of the different applied technical parameters, and this way, guide the professionals as for the possibility of obtaining of x-ray images of better quality and smaller patient exposition. For radiation dose measure a detector of solid state was utilized. During the accomplishment of the measures it was verified that there no a general consensus among the technicians of the section being observed differences of the order of 80% in the mAs. In terms of radiation dose measured, the largest value of verified was 4.752 mGy (exam of lateral lumbar column) and the smallest value of 0.165 mGy (child's thorax).The results showed that a standardization in the x-ray techniques executed by the professionals of the section will be able to reduce significantly the radiation exposition of the assisted patients. (author)

  14. Study of the variation of radiation dose in function of the radiological techniques used in X-ray diagnosis exams

    International Nuclear Information System (INIS)

    Fernandes, Marco A.R.; Reis, Charlene O.; Garcia, Paulo L.; Lima, Marcelo A.F.; Dalaqua, Fernando L.D.

    2011-01-01

    This paper values the importance of the implantation of a quality control program in medical x-ray diagnosis services that it seeks mainly to the reduction of the radiation dose applied in the radiology exams, and attempt to the precepts of the Effective Legislation as for the Basic Guidelines of Radiological Protection (law decree MS no. 453 in June 1 st 1998). The study was accomplished Radiology Section of the Medicine Faculty - FMB (UNESP - Botucatu) and it consisted of the accomplishment of measures of the radiation dose applied in the radiological exams, taking as base the x-rays techniques realized by four technicians in radiology the service, using only one x-rays equipment. Was intended analyze the variation of the radiation dose in function of the different applied technical parameters, and this way, guide the professionals as for the possibility of obtaining of x-ray images of better quality and smaller patient exposition. For radiation dose measure a detector of solid state was utilized. During the accomplishment of the measures it was verified that there no a general consensus among the technicians of the section being observed differences of the order of 80% in the mAs. In terms of radiation dose measured, the largest value of verified was 4.752 mGy (exam of lateral lumbar column) and the smallest value of 0.165 mGy (child's thorax).The results showed that a standardization in the x-ray techniques executed by the professionals of the section will be able to reduce significantly the radiation exposition of the assisted patients. (author)

  15. Contribution of Topography and Incident Solar Radiation to Variation of Soil and Plant Litter at an Area with Heterogeneous Terrain

    Directory of Open Access Journals (Sweden)

    Felipe Cito Nettesheim

    2015-06-01

    Full Text Available Natural processes that determine soil and plant litter properties are controlled by multiple factors. However, little attention has been given to distinguishing the effects of environmental factors from the effects of spatial structure of the area on the distribution of soil and litter properties in tropical ecosystems covering heterogeneous topographies. The aim of this study was to assess patterns of soil and litter variation in a tropical area that intercepts different levels of solar radiation throughout the year since its topography has slopes predominantly facing opposing geographic directions. Soil data (pH, C, N, P, H+Al, Ca, Mg, K, Al, Na, sand, and silt and plant litter data (N, K, Ca, P, and Mg were gathered together with the geographic coordinates (to model the spatial structure of 40 sampling units established at two sites composed of slopes predominantly facing northwest and southeast (20 units each. Soil and litter chemical properties varied more among slopes within similar geographic orientations than between the slopes facing opposing directions. Both the incident solar radiation and the spatial structure of the area were relevant in explaining the patterns detected in variation of soil and plant litter. Individual contributions of incident solar radiation to explain the variation in the properties evaluated suggested that this and other environmental factors may play a particularly relevant role in determining soil and plant litter distribution in tropical areas with heterogeneous topography. Furthermore, this study corroborates that the spatial structure of the area also plays an important role in the distribution of soil and litter within this type of landscape, which appears to be consistent with the action of water movement mechanisms in such areas.

  16. Nonlinear real index of refraction variations of a gas medium due to a monochromatic radiation near resonance

    International Nuclear Information System (INIS)

    Vasconcellos, J.I.C.

    1982-01-01

    The nonlinear real index of refraction variations of a gas medium due to a strong monochromatic radiation causing saturation effects is calculated. The gas is supposed to be composed of two-level molecules with which the external field is nearly resonant. It is assumed homogeneous (hard collisions, spontaneous decay) and inhomogeneous (Doppler effect) broadening mechanisms acting on the real index of refraction of the medium. The nonlinear dispersion of the medium is studied as a function of the detuning frequencies, saturation conditions and for various ratios between the homogeneous and inhomogeneous linewidths. In particular, the modification of the index of refraction due to saturation effects are emphasized. (Author) [pt

  17. Storm Time Variation of Radiative Cooling by Nitric Oxide as Observed by TIMED-SABER and GUVI

    Science.gov (United States)

    Bharti, Gaurav; Sunil Krishna, M. V.; Bag, T.; Jain, Puneet

    2018-02-01

    The variation of O/N2 (reference to N2 column density 1017 cm-2) and nitric oxide radiative emission flux exiting the thermosphere have been studied over the Northern Hemisphere during the superstorm event of 7-12 November 2004. The data have been obtained from Global Ultraviolet Imager (GUVI) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) on board the National Aeronautics and Space Administration (NASA)'s Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) satellite. The NO radiative flux is observed to show an anti-correlation with O/N2 on a global scale. Both NO radiative flux and O/N2 ratio show equatorward motion with maximum penetration in western longitude sectors. A local variation of O, O2, and N2 densities have been calculated using NRLMSISE-00 model over a midlatitude location (55°N,180°E). On a local scale, model calculated O/O2 and O/N2 ratios are found to follow the observations made by GUVI. The collisional excitation of NO with atomic oxygen is the most dominant process for the total cooling rate. The SABER-retrieved NO cooling rate (CR) at a local site suggests an enhancement during the storm period with the peak emission rate closely correlated to the progression of the storm. The peak emission altitude of NO CR moves upward during the main phase of the storm. The NO abundance has been calculated by using cooling rate and Nitric Oxide Empirical Model (NOEM) model. Both these suggest a vary large (3-15 times) increase in NO density during the storm, which is required to account the changes in NO radiative flux. A similar kind of enhancement in NO abundance is also noticed in Student Nitric Oxide Explorer observations during intense geomagnetic storms.

  18. HERSCHEL -RESOLVED OUTER BELTS OF TWO-BELT DEBRIS DISKS—EVIDENCE OF ICY GRAINS

    Energy Technology Data Exchange (ETDEWEB)

    Morales, F. Y.; Bryden, G.; Werner, M. W.; Stapelfeldt, K. R., E-mail: Farisa@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2016-11-01

    We present dual-band Herschel /PACS imaging for 59 main-sequence stars with known warm dust ( T {sub warm} ∼ 200 K), characterized by Spitzer . Of 57 debris disks detected at Herschel wavelengths (70 and/or 100 and 160 μ m), about half have spectral energy distributions (SEDs) that suggest two-ring disk architectures mirroring that of the asteroid–Kuiper Belt geometry; the rest are consistent with single belts of warm, asteroidal material. Herschel observations spatially resolve the outer/cold dust component around 14 A-type and 4 solar-type stars with two-belt systems, 15 of which for the first time. Resolved disks are typically observed with radii >100 AU, larger than expected from a simple blackbody fit. Despite the absence of narrow spectral features for ice, we find that the shape of the continuum, combined with resolved outer/cold dust locations, can help constrain the grain size distribution and hint at the dust’s composition for each resolved system. Based on the combined Spitzer /IRS+Multiband Imaging Photometer (5-to-70 μ m) and Herschel /PACS (70-to-160 μ m) data set, and under the assumption of idealized spherical grains, we find that over half of resolved outer/cold belts are best fit with a mixed ice/rock composition. Minimum grain sizes are most often equal to the expected radiative blowout limit, regardless of composition. Three of four resolved systems around the solar-type stars, however, tend to have larger minimum grains compared to expectation from blowout ( f {sub MB} = a {sub min}/ a {sub BOS} ∼ 5). We also probe the disk architecture of 39 Herschel -unresolved systems by modeling their SEDs uniformly, and find them to be consistent with 31 single- and 8 two-belt debris systems.

  19. Tumor response parameters for head and neck cancer derived from tumor-volume variation during radiation therapy

    International Nuclear Information System (INIS)

    Chvetsov, Alexei V.

    2013-01-01

    Purpose: The main goal of this paper is to reconstruct a distribution of cell survival fractions from tumor-volume variation for a heterogeneous group of head and neck cancer patients and compare this distribution to the data from predictive assays. Methods: To characterize the tumor-volume variation during radiation therapy treatment, the authors use a two-level tumor-volume model of cell population that separates the entire tumor cell population into two subpopulations of viable cells and lethally damaged cells. This parameterized radiobiological model is integrated with a least squares objective function and a simulated annealing optimization algorithm to describe time-dependent tumor-volume variation rates in individual patients. Several constraints have been used in the optimization problem because tumor-volume variation during radiotherapy is described by a sum of exponentials; therefore, the problem of accurately fitting a model to measured data is ill-posed. The model was applied to measured tumor-volume variation curves from a clinical study on tumor-volume variation during radiotherapy for 14 head and neck cancer patients in which an integrated CT/linear particle accelerator (LINAC) system was used for tumor-volume measurements. Results: The two-level cell population tumor-volume modeling is capable of describing tumor-volume variation throughout the entire treatment for 11 of the 14 patients. For three patients, the tumor-volume variation was described only during the initial part of treatment, a fact that may be related to the neglected hypoxia in the two-level approximation. The predicted probability density distribution for the survival fractions agrees with the data obtained using in vitro studies with predictive assays. The mean value 0.35 of survival fraction obtained in this study is larger than the value 0.32 from in vitro studies, which could be expected because of greater repair in vivo. The mean half-life obtained in this study for the head

  20. Evaluating the role of mitochondrial DNA variation to the genetic predisposition to radiation-induced toxicity

    International Nuclear Information System (INIS)

    Fachal, Laura; Mosquera-Miguel, Ana; Gómez-Caamaño, Antonio; Sánchez-García, Manuel; Calvo, Patricia; Lobato-Busto, Ramón; Salas, Antonio; Vega, Ana

    2014-01-01

    Background and purpose: Mitochondrial DNA common variants have been reported to be associated with the development of radiation-induced toxicity. Using a large cohort of patients, we aimed to validate these findings by investigating the potential role of common European mitochondrial DNA SNPs (mtSNPs) to the development of radio-toxicity. Material and methods: Overall acute and late toxicity data were assessed in a cohort of 606 prostate cancer patients by means of Standardized Total Average Toxicity (STAT) score. We carried out association tests between radiation toxicity and a selection of 15 mtSNPs (and the haplogroups defined by them). Results: Statistically significant association between mtSNPs and haplogroups with toxicity could not be validated in our Spanish cohort. Conclusions: The present study suggests that the mtDNA common variants analyzed are not associated with clinically relevant increases in risk of overall radiation-induced toxicity in prostate cancer patients

  1. Conformational variation of proteins at room temperature is not dominated by radiation damage

    International Nuclear Information System (INIS)

    Russi, Silvia; González, Ana; Kenner, Lillian R.; Keedy, Daniel A.; Fraser, James S.; Bedem, Henry van den

    2017-01-01

    Protein crystallography data collection at synchrotrons is routinely carried out at cryogenic temperatures to mitigate radiation damage. Although damage still takes place at 100 K and below, the immobilization of free radicals increases the lifetime of the crystals by approximately 100-fold. Recent studies have shown that flash-cooling decreases the heterogeneity of the conformational ensemble and can hide important functional mechanisms from observation. These discoveries have motivated increasing numbers of experiments to be carried out at room temperature. However, the trade-offs between increased risk of radiation damage and increased observation of alternative conformations at room temperature relative to cryogenic temperature have not been examined. A considerable amount of effort has previously been spent studying radiation damage at cryo-temperatures, but the relevance of these studies to room temperature diffraction is not well understood. Here, the effects of radiation damage on the conformational landscapes of three different proteins (T. danielli thaumatin, hen egg-white lysozyme and human cyclophilin A) at room (278 K) and cryogenic (100 K) temperatures are investigated. Increasingly damaged datasets were collected at each temperature, up to a maximum dose of the order of 10 7 Gy at 100 K and 10 5 Gy at 278 K. Although it was not possible to discern a clear trend between damage and multiple conformations at either temperature, it was observed that disorder, monitored by B-factor-dependent crystallographic order parameters, increased with higher absorbed dose for the three proteins at 100 K. At 278 K, however, the total increase in this disorder was only statistically significant for thaumatin. A correlation between specific radiation damage affecting side chains and the amount of disorder was not observed. Lastly, this analysis suggests that elevated conformational heterogeneity in crystal structures at room temperature is observed despite radiation

  2. Files for workstations with ionizing radiation risks: variation in the use of gamma densitometers

    International Nuclear Information System (INIS)

    Tournadre, A.

    2008-01-01

    After a brief presentation of the different gamma-densitometers proposed by MLPC to measure roadway density, and having outlined the support role of the provider, the author describes the form and content of workstation files for workstations exhibiting a risk related to ionizing radiation. He gives an analytical overview of dose calculation: analysis of instrument use phases, exposure duration, dose rates and way of introducing these dose rates in the workstation file. He formulates how different procedures are to be followed by the radiation protection expert within the company. He outlines that workstation files are very useful as information feedback tool

  3. Study of the Variation of Material layer Compotition and Thickness Related Neutron Flux and Gamma Radiation

    Science.gov (United States)

    Nirmalasari, Yuliana Dian; Suparmi; Sardjono, Y.

    2017-11-01

    Optimation of simulation design of collimator is corresponding to 30 MeV cyclotron generator. The simulation has used the variation of the thickness materials layers that was applied at treatment room’s door. The purpose of the variation and thickness of the material in this simulation to obtain optimum results for the shielding design in the irradiation chamber. The layers that we used are Pb-Fe and Pb-SS312. Simulation on cancer treatment is used with monte carlo simaulation MCNPX. The spesifications that we used for cyclotron is the spesification of the HM-30 Proton Cyclotron from Sumitomo Heavy Industries Ltd. The variation of the thickness materials layers that was applied at treatment room’s door are Pb remains 4cm while Fe and SS312 varies between 2 cm, 4 cm, 6 cm respectively. This simulation of Fe layer on Pb was give good result in measurement simulation at 4 cm thickness.

  4. Device for determining the content of bulk materials on conveyor belts

    International Nuclear Information System (INIS)

    Fritsche, D.

    1983-01-01

    On the basis of the forward scattering of photon radiation the invention is aimed at determining the content of bulk material, in particular the ash content of lignite, independently of the height of the material conveyed by belts. This could be achieved by making the radiation source support movable, so that the distance between source and conveyor belt is variable and adaptable to the mean height of the bulk material

  5. AUTOMATION OF CONVEYOR BELT TRANSPORT

    Directory of Open Access Journals (Sweden)

    Nenad Marinović

    1990-12-01

    Full Text Available Belt conveyor transport, although one of the most economical mining transport system, introduce many problems to mantain the continuity of the operation. Every stop causes economical loses. Optimal operation require correct tension of the belt, correct belt position and velocity and faultless rolls, which are together input conditions for automation. Detection and position selection of the faults are essential for safety to eliminate fire hazard and for efficient maintenance. Detection and location of idler roll faults are still open problem and up to now not solved successfully (the paper is published in Croatian.

  6. Variation in radiation sensitivity and repair kinetics in different parts of the spinal cord

    International Nuclear Information System (INIS)

    Adamus-Gorka, Magdalena; Brahme, Anders; Mavroidis, Panayiotis; Lind, Bengt K.

    2008-01-01

    Background. The spinal cord, known for its strongly serial character and high sensitivity to radiation even when a small segment is irradiated, is one of the most critical organs at risk to be spared during radiation therapy. To compare the sensitivity of different parts of the spinal cord, data for radiation myelopathy have been used. Material and methods. In the present study, the relative seriality model was fitted to two different datasets of clinical radiation myelitis concerning cervical spinal cord after treating 248 patients for head and neck cancer and thoracic spinal cord after treating 43 patients with lung carcinoma. The maximum likelihood method was applied to fit the clinical data. The model parameters and their 68% confidence intervals were calculated for each dataset. The α/β ratio for the thoracic cord was also was also found to be 0.9 (0-3.0) Gy. Results. The dose-response curve for the more sensitive cervical myelopathy is well described by the parameters D 50 =55.9 (54.8-57.1) Gy, γ=6.9 (5.0-9.2), s=0.13 (0.07-0.24), whereas the thoracic myelopathy is described by the parameters D 50 =75.5 (70.5-80.8) Gy, γ=1.1 (0.6-1.6), s=36 (3.3-8). Discussion and conclusions. Large differences in radiation response between the cervical and thoracic region of spinal cord are thus observed: cervical myelopathy seems to be characterized by medium seriality, while thoracic spinal cord is characterized by a highly serial dose-response. The much steeper dose-response curve for cervical spinal cord myelopathy can be interpreted as a higher number of functional subunits consistent with a higher amount of white matter close to the brain

  7. Spatial and temporal variations of albedo and absorbed solar radiation during 2009 - 2016 from IKOR-M satellite program

    Science.gov (United States)

    Cherviakov, Maksim; Bogdanov, Mikhail; Spiryakhina, Anastasia; Shishkina, Elena; Surkova, Yana; Kulkova, Eugenia

    2017-04-01

    -M. This radiometer worked on board of the "Meteor-M" No 1 satellite for five years. Parameters of linear trends are estimated for the Earth's surface area albedo with approximately constant values of this characteristic and the estimate of sensitivity change over time for the radiometer is obtained. The seasonal and interannual variations of OSR, albedo and ASR were discussed. The variations between SW radiation budget components seem to be within observational uncertainty and natural variability governed by cloudiness, water vapor and aerosol variations. It should be noted that cloudiness makes a significant contribution to the planetary albedo of the Earth, largely determines its spatial-temporal distribution. In particular, it is important to know what contribution cloudiness makes to albedo and what the relationship between them. Therefore, comparisons between albedo and cloudiness were conducted separately for land and oceans. The comparison of the distributions of cloudiness and albedo had identified the existence of significant correlation to the World Ocean, lower values for the World Ocean and land together and small correlation for land. It was assessed spatial and temporal variations of albedo and the absorbed solar radiation over different regions. Latitudinal distributions of albedo and ASR were estimated in more detail. Meridional cross sections over oceans and land were used separately for this estimation. It was shown that the albedo and ASR data received from the radiometer IKOR-M can be used to detect El Nino in the Pacific Ocean and monitoring of the East Asian Summer Monsoon. The report will be presented more detailed results. The reported study was funded by Russian Geographical Society according financial support in the framework of a research project No 40/2016-R. Latitudinal distributions of albedo and ASR study was funded by RFBR according to the research project No.16-35-00284 mol_a. References 1. Sklyarov Yu.A., Vorob'ev V.A., Kotuma A

  8. Investigation of a new type charging belt

    International Nuclear Information System (INIS)

    Jones, N.L.

    1994-01-01

    There are many desirable characteristics for an electrostatic accelerator charging belt. An attempt has been made to find a belt that improves on these properties over the stock belt. Results of the search, procurement, and 1,500 hours of operational experience with a substantially different belt are reported

  9. MVP: A Simple and Effective Model to Simulate the Mean and Variation of Photosynthetically Active Radiation Under Discrete Forest Canopies

    Science.gov (United States)

    Song, C.; Band, L. E.

    2003-12-01

    The spatial patterns of Photosynthetically Active Radiation (PAR) under forest canopies, including both its mean and spatial variation, are critical factors that determine numerous ecophysiological processes in plant ecosystems. Though numerous models have been developed that can accurately simulate PAR transmission through plant canopies, Beer's law remains the primary model used in ecological models to describe PAR transmission through plant canopies due to the fact that the more accurate models are too complicated to be used operationally. This study developed a simple and computationally efficient model to simulate both the Mean and Variation of PAR (MVP) under the forest canopy. The model provides a careful description of the effects of gaps on the variable light environment under forest canopy, while it simplifies the simulation of multiple scattering of photons. The model assumes that a forest canopy is composed of individual crowns distributed within upper and lower boundaries with two types of gaps: the between- and within-crown gaps. The inputs to the model are canopy structural parameters, including canopy depth, tree count density, tree crown shape, and foliage area volume density (m2/m3, leaf areas per unit crown volume). The between-crown gaps are simulated with geometric optics, and the within-crown gaps are described by Beer's law. The model accounts for the covariance of PAR in space through time, making it possible to simulate both instantaneous variation of PAR and variation of daily accumulated PAR. Validation with observed PAR using ten quantum sensors under the Old Black Spruce stand at the Southern Study Area of the BOREAS project indicates the model captures the mean and variation of PAR under forest canopy reasonably well. The model is simple enough that it can be used by other ecological models, such as ecosystem dynamics and carbon budget models. Further validation and testing of the model with other types forest are needed in the future.

  10. a Study of the Impact of Doubling Carbon Dioxide and Solar Radiation Variations on the Climate System.

    Science.gov (United States)

    Chu, Shaoping

    The exchange of moisture and heat between the atmosphere and the Earth's surface fundamentally affect the dynamics and thermodynamics of the climate system. In order to trace moisture flow through the climate system and examine its impact on climate, a hydrologic cycle and a land energy balance have been developed and incorporated into a coupled climate-thermodynamic sea ice (CCSI) model. The expanded CCSI model has been tested by comparing computed climate parameters with available observations and GCM modeling results. In general, the expanded model does a good job in simulating the large scale features of the atmospheric circulation and precipitation in both space and time. The expanded model has been used to examine the possibility that increased levels of CO_2 in the atmosphere may induce the growth of Northern Hemisphere ice sheets. Results of the study indicate that if summer ice albedo is high enough, and there is some mechanism for initially maintaining ice through the summer season, then it may be possible to have ice sheet growth under the conditions CO_2 induced warming, mainly the result of decreased summer ice melt in response to the higher land ice albedo, and not an increase in precipitation. The expanded model has also been used to examine the impact of Milankovitch solar radiation variations on the climate system, to study the mechanisms that produce glacial-interglacial cycles, especially with respect to the initiation of ice sheets. The results show the Milankovitch solar radiation variations affect the climate system most in the polar regions with the mean annual surface air temperature varying directly in response to changes in the annually averaged incoming solar radiation. However, the seasonal variations in the surface air temperatures are much more complex with large magnitude variations for brief times during the year. The study indicates that ice sheets may start to grow under the conditions of low insolation that occurred at 25, 70, and

  11. Jupiter radiation belt models (July 1974)

    International Nuclear Information System (INIS)

    Divine, N.

    1974-01-01

    Flux profiles which were derived from data returned by Pioneer 10 during Jupiter encounter, form the basis for a new set of numerical models for the energy spectra of electrons and protons in Jupiter's inner magnetosphere

  12. 30 CFR 75.1731 - Maintenance of belt conveyors and belt conveyor entries.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maintenance of belt conveyors and belt conveyor....1731 Maintenance of belt conveyors and belt conveyor entries. (a) Damaged rollers, or other damaged belt conveyor components, which pose a fire hazard must be immediately repaired or replaced. All other...

  13. Chaos on the conveyor belt.

    Science.gov (United States)

    Sándor, Bulcsú; Járai-Szabó, Ferenc; Tél, Tamás; Néda, Zoltán

    2013-04-01

    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 a 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 be achieved only 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).

  14. Storm/substorm signatures in the outer belt

    International Nuclear Information System (INIS)

    Korth, A.; Friedel, R.H.W.; Mouikis, C.; Fennell, J.F.

    1998-01-01

    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

  15. Monthly and seasonal variations of aerosol optical properties and direct radiative forcing over Zanjan, Iran

    Science.gov (United States)

    Gharibzadeh, Maryam; Alam, Khan; Abedini, Yousefali; Bidokhti, Abbasali Aliakbari; Masoumi, Amir

    2017-11-01

    Aerosol optical properties and radiative forcing over Zanjan in northwest of Iran has been analyzed during 2010-2013. The aerosol optical and radiative properties are less studied over Zanjan, and therefore, require a careful and in depth analysis. The optical properties like Aerosol Optical Depth (AOD), Ångström Exponent (AE), ASYmmetry parameter (ASY), Single Scattering Albedo (SSA), and Aerosol Volume Size Distribution (AVSD) have been evaluated using the ground-based AErosol RObotic NETwork (AERONET) data. Higher AOD while relatively lower AE were observed in the spring and summer, which showed the presence of coarse mode particles in these seasons. An obvious increase of coarse mode particles in AVSD distribution, as well as a higher value of SSA represented considerable addition of coarse mode particles like dust into the atmosphere of Zanjan in these two seasons. Increase in AE, while a decrease in AOD was detected in the winter and fall. The presence of fine particles indicates the dominance of particles like urban-industrial aerosols from local sources especially in the winter. The Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model was utilized to calculate the Aerosol Radiative Forcing (ARF) at the Top of the Atmosphere (TOA), earth's surface and within the atmosphere. The annual averaged ARF values were -13.47 W m-2 and -36.1 W m-2 at the TOA and earth's surface, respectively, which indicate a significant cooling effect. Likewise, the ARF efficiencies at the TOA and earth's surface were -65.08 W m-2 and -158.43 W m-2, respectively. The annual mean atmospheric ARF and heating rate within the atmosphere were 22.63 W m-2 and 0.27 Kday-1 respectively, represented the warming effect within the atmosphere. Finally, a good agreement was found between AERONET retrieved ARF and SBDART simulated ARF.

  16. Probiotics for Rectal Volume Variation During Radiation Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ki, Yongkan [Department of Radiation Oncology, Pusan National University School of Medicine, Busan (Korea, Republic of); Kim, Wontaek, E-mail: rokwt@hanmail.net [Department of Radiation Oncology, Pusan National University School of Medicine, Busan (Korea, Republic of); Nam, Jiho; Kim, Donghyun; Lee, Juhye; Park, Dahl; Jeon, Hosang [Department of Radiation Oncology, Pusan National University School of Medicine, Busan (Korea, Republic of); Ha, Honggu; Kim, Taenam [Department of Urology, Medical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of); Kim, Dongwon [Department of Radiation Oncology, Pusan National University School of Medicine, Busan (Korea, Republic of)

    2013-11-15

    Purpose: To investigate the effect of the probiotic Lactobacillus acidophilus on the percentage volume change of the rectum (PVC{sub R}), a crucial factor of prostate movement. Methods and Materials: Prostate cancer patients managed with tomotherapy as a radical treatment were enrolled in the study to take a probiotic capsule containing 1.0 × 10{sup 8} colony-forming units of L acidophilus or a placebo capsule twice daily. Radiation therapy was performed at a dose of 78 Gy in 39 fractions. The PVC{sub R}, defined as the difference in rectal volume between the planning computed tomographic (CT) and daily megavoltage CT images, was analyzed. Results: Forty patients were randomized into 2 groups. The L acidophilus group showed significantly lower median rectal volume and median PVC{sub R} values than the placebo group. L acidophilus showed a significant reduction effect on the PVC{sub R} (P<.001). However, the radiation therapy fraction number did not significantly influence the PVC{sub R}. Conclusions: L acidophilus was useful in reducing the PVC{sub R}, which is the most important determining factor of prostate position, during radiation therapy for prostate cancer.

  17. SU-E-T-636: Investigation of Dose Variation in High Dose Radiation Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hyvarinen, M; Leventouri, T; Casey, C; Long, S [Florida Atlantic University, Boca Raton, FL (United States); Pella, S [South Florida Radiation Oncology and Florida Atlantic University, Boca Raton, FL (United States); Dumitru, N [University of Bucharest, Bucharest-magurele, Ilfov (Romania); Herrera, R [Louis Stokes VA Medical Center, Cleveland, OH (United States)

    2014-06-15

    Purpose: The purpose of this study is to revise most of the HDR types of treatments with their applicators and their localization challenges. Since every millimeter of misplacement counts the study will look into the necessity of increasing the immobilization for several types of applicators Methods: The study took over 136 plans generated by the treatment planning system (TPS) looking into the applicator's placement in regard to the organs at risk (OR) and simulated the three possible displacements at the hottest dose point on the critical organ for several accessories to evaluate the variation of the delivered dose at the point due to the displacement. Results: Significant dose variation was obtained for the Contura, Savi, MLM and Prostate applicators. Conclusion: This study data indicates that an improvement of the immobilization devices for HDR is absolutely necessary. Better applicator fixation devices are required too. Developing new immobilization devices for all the applicators is recommended. Florida Atlantic University may provide Travel reimbursements.

  18. Variation method for optimization of Raman fiber amplifier pumped by continuous-spectrum radiation

    International Nuclear Information System (INIS)

    Ghasempour Ardekani, A.; Bahrampour, A. R.; Feizpour, A.

    2007-01-01

    In Raman fiber amplifiers, reduction of gain ripple versus frequency has a great importance. In this article using variational method and continuous pump, gain ripple is optimized. It is shown here that for a 40 km line the average gain is 1.3dB and the gain ripple is 0.12 dB, that is lower than the latest published data.

  19. Studying the effect of spectral variations intensity of the incident solar radiation on the Si solar cells performance

    Directory of Open Access Journals (Sweden)

    Ahmed Elsayed Ghitas

    2012-12-01

    Full Text Available Solar spectral variation is important in characterization of photovoltaic devices. We present results of an experimental investigation of the effects of the daily spectral variation on the device performance of multicrystalline silicon photovoltaic module. The investigation concentrate on the analysis of outdoor solar spectral measurements carried out at 1 min intervals on clear sky days. Short circuit current and open circuit voltage have been measured to describe the module electrical performance. We have shown that the shift in the solar spectrum towards infrared has a negative impact on the device performance of the module. The spectral bands in the visible region contribute more to the short circuit current than the bands in the infrared region while the ultraviolet region contributes least. The quantitative effect of the spectral variation on the performance of the photovoltaic module is reflected on their respective device performance parameters. The decrease in the visible and the increase in infrared of the radiation spectra account for the decreased current collection and hence power of the module.

  20. Mobile belt conveyor

    OpenAIRE

    Tenora, Jiří

    2017-01-01

    Cílem bakalářské práce je návrh pásového dopravníku pro přepravu drobného kameniva, zeminy a drobné stavební sutě s dopravním výkonem 60 t/h, výškovým rozdílem 3,5 m a vzdáleností mezi osami bubnů 8 m. Tato práce obsahuje také popis základních částí pásového dopravníku, funkční výpočty podle normy ČSN ISO 5048, návrh hlavních rozměrů dopravníku a pohonu. Celá práce se skládá z technické zprávy a výkresové dokumentace. The aim of this word is to design belt conveyor to transport tiny aggreg...

  1. In vitro induction of variation through radiation for late blight resistance and heat tolerance in potato

    Energy Technology Data Exchange (ETDEWEB)

    Minocha, J L; Das, A; Gopal, J; Gosal, S S [Biotechnology Centre, Punjab Agricultural Univ., Ludhiana, Punjab (India)

    1997-07-01

    In vitro plants were obtained from nodal sections of sprouts of cvs. `Kufri Jyoti` and `Kufri Chandramukhi` of potato cultured on MS medium with 3% sucrose. Callus from leaves of in vitro cultured plantlets was induced on modified Linsmaier and Skoog medium supplemented with 5 mg/1 NAA. The obtained shoots and calli were irradiated with 20 and 40 Gy gamma rays. Irradiatied shoots were transferred to MS medium with 8% sucrose for multiplication, and then to MS medium with 8% sucrose and 10 mg/1 BAP to induce microtuber formation, which gave on average 1.3 microtubers per plant. The microtubers were planted in pots and variation was observed in plant morphology and tuber characters. To study variation for late blight resistance, irradiated calli were kept on Gamborg B-5 medium with culture filtrate of Phytophthora infestans. To induce variation for heat tolerance, in vitro shoots from irradiated material were mass-propagated and allowed to produce microtubers at high temperature. (author). 3 refs, 3 tabs.

  2. In vitro induction of variation through radiation for late blight resistance and heat tolerance in potato

    International Nuclear Information System (INIS)

    Minocha, J.L.; Das, A.; Gopal, J.; Gosal, S.S.

    1997-01-01

    In vitro plants were obtained from nodal sections of sprouts of cvs. 'Kufri Jyoti' and 'Kufri Chandramukhi' of potato cultured on MS medium with 3% sucrose. Callus from leaves of in vitro cultured plantlets was induced on modified Linsmaier and Skoog medium supplemented with 5 mg/1 NAA. The obtained shoots and calli were irradiated with 20 and 40 Gy gamma rays. Irradiatied shoots were transferred to MS medium with 8% sucrose for multiplication, and then to MS medium with 8% sucrose and 10 mg/1 BAP to induce microtuber formation, which gave on average 1.3 microtubers per plant. The microtubers were planted in pots and variation was observed in plant morphology and tuber characters. To study variation for late blight resistance, irradiated calli were kept on Gamborg B-5 medium with culture filtrate of Phytophthora infestans. To induce variation for heat tolerance, in vitro shoots from irradiated material were mass-propagated and allowed to produce microtubers at high temperature. (author). 3 refs, 3 tabs

  3. Radiation and chemical mutagen induced somaclonal variations through in vitro organogenesis of cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Muthusamy, Annamalai; Jayabalan, Narayanasamy

    2014-12-01

    The purpose of the investigation was to induce somaclonal variations by gamma rays (GR), ethylmethane sulphonate (EMS) and sodium azide (SA) during in vitro organogenesis of cotton. The shoot tip explants were irradiated with 5-50 Gray (Gy) GR (Cobalt 60), 0.5-5.0 mM EMS and SA separately, and inoculated on Murashige and Skoog (MS) medium fortified with plant growth regulator (PGR) for organogenesis. The plantlets with well-developed root systems were acclimatized and transferred into the experimental field to screen the somaclonal variations during growth and development. The number of somaclonal variations was observed in growth of irradiated/treated shoot tips, multiplication, plantlet regeneration and growth in vitro and ex vitro. The lower doses/concentrations of mutagenic treatments showed significant enhancement in selected agronomical characters and they showed decreased trends with increasing doses/concentrations of mutagenic agents. The results of the present study revealed the influence of lower doses/concentrations of mutagenic treatments on in vitro and ex vitro growth of cotton plantlets and their significant improvement in agronomical characters which needs further imperative stability analysis. The present observations showed the platform to use lower doses/concentrations of mutagenic agents to induce variability for enhanced agronomical characters, resistant and tolerant cotton varieties.

  4. Radiation

    International Nuclear Information System (INIS)

    2013-01-01

    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

  5. Variations on metabolic activities of legume tissues through radiation in tissue culture

    International Nuclear Information System (INIS)

    Batra, Amla

    1977-01-01

    Cell cultures from Arachis hypogaea L. cultivated in a modified medium developed by Murashige and Skoog (1962) showed vigorous qrowth after radiation treatment. Investigations on the effect of various sugars on the chlorophyll formation and growth of the irradiated tissues showed that sucrose was superior to maltose, glucose or fructose as a carbon source. Lactose and mannitol supported growth and development of chlorophyll to a less degree. On prolonging the cultures on a sugar free medium, the tissues failed to regain either growth or chlorophyll content. (author)

  6. Variations on metabolic activities of legume tissues through radiation in tissue culture

    Energy Technology Data Exchange (ETDEWEB)

    Batra, A [Rajasthan Univ., Jaipur (India). Dept. of Botany

    1977-12-01

    Cell cultures from Arachis hypogaea L. cultivated in a modified medium developed by Murashige and Skoog (1962) showed vigorous qrowth after radiation treatment. Investigations on the effect of various sugars on the chlorophyll formation and growth of the irradiated tissues showed that sucrose was superior to maltose, glucose or fructose as a carbon source. Lactose and mannitol supported growth and development of chlorophyll to a less degree. On prolonging the cultures on a sugar free medium, the tissues failed to regain either growth or chlorophyll content.

  7. Belt conveyors for bulk materials. 6th ed.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The 16 chapters are entitled: Belt conveyor general applications economics; Design considerations; Characteristics and conveyability of bulk materials; Capacities, belt widths and speeds; Belt conveyor idlers; Belt tension and power engineering; Belt selection; Pulleys and shafts; Curves; Steep angle conveying; Belt cleaners and accessories; Transfer points; Conveyor motor drives and controls; Operation, maintenance and safety; Belt takeups; and Emerging technologies. 6 apps.

  8. Effectiveness of Ford's belt reminder system in increasing seat belt use

    OpenAIRE

    Williams, A; Wells, J; Farmer, C

    2002-01-01

    Objectives: The study investigated the effectiveness in increasing seat belt use of Ford's belt reminder system, a supplementary system that provides intermittent flashing lights and chimes for five minutes if drivers are not belted.

  9. Probiotics for Rectal Volume Variation During Radiation Therapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Ki, Yongkan; Kim, Wontaek; Nam, Jiho; Kim, Donghyun; Lee, Juhye; Park, Dahl; Jeon, Hosang; Ha, Honggu; Kim, Taenam; Kim, Dongwon

    2013-01-01

    Purpose: To investigate the effect of the probiotic Lactobacillus acidophilus on the percentage volume change of the rectum (PVC R ), a crucial factor of prostate movement. Methods and Materials: Prostate cancer patients managed with tomotherapy as a radical treatment were enrolled in the study to take a probiotic capsule containing 1.0 × 10 8 colony-forming units of L acidophilus or a placebo capsule twice daily. Radiation therapy was performed at a dose of 78 Gy in 39 fractions. The PVC R , defined as the difference in rectal volume between the planning computed tomographic (CT) and daily megavoltage CT images, was analyzed. Results: Forty patients were randomized into 2 groups. The L acidophilus group showed significantly lower median rectal volume and median PVC R values than the placebo group. L acidophilus showed a significant reduction effect on the PVC R (P R . Conclusions: L acidophilus was useful in reducing the PVC R , which is the most important determining factor of prostate position, during radiation therapy for prostate cancer

  10. An investigation into CT radiation dose variations for head examinations on matched equipment

    International Nuclear Information System (INIS)

    Zarb, Francis; Foley, Shane; Toomey, Rachel; Rainford, Louise; Holm, Susanne; Evanoff, Michael G.

    2016-01-01

    This study investigated radiation dose and image quality differences for computed tomography (CT) head examinations across centres with matched CT equipment. Radiation dose records and imaging protocols currently employed across three European university teaching hospitals were collated, compared and coded as Centres A, B and C from specification matched CT equipment models. Patient scans (n = 40) obtained from Centres A and C were evaluated for image quality, based on the visualisation of Commission of European Community (CEC) image quality criteria using visual grading characteristic (VGC) analysis, where American Board of Radiology examiners (n = 11) stated their confidence in identifying anatomical criteria. Mean doses in terms of CT dose index (CTDI vol -mGy) and dose length product (DLP-mGy cm) were as follows: Centre A-33.12 mGy and 461.45 mGy cm; Centre B -101 mGy (base)/32 mGy (cerebrum) and 762 mGy cm and Centre C-71.98 mGy and 1047.26 mGy cm, showing a significant difference (p ≤ 0.05) in DLP across centres. VGC analysis indicated better visualisation of CEC criteria on Centre C images (VGC AUC 0.225). All three imaging protocols are routinely used clinically, and image quality is acceptable in each centre. Clinical centres with identical model CT scanners have variously customised their protocols achieving a range of dose savings and still resulting in clinically acceptable image quality. (authors)

  11. Variations with time and age in the relative risks of solid cancer incidence after radiation exposure

    International Nuclear Information System (INIS)

    Little, M.P.; Muirhead, C.R.; de Vathaire, F.; Charles, M.W.

    1997-01-01

    The Japanese atomic bomb survivor cancer incidence dataset and data on five groups exposed to radiation for medical reasons in childhood are analysed and evidence found for a reduction in the radiation-induced relative risk of cancers other than leukaemia with increasing time since exposure and age at exposure. The rate of the reductions in relative risk with time since exposure are not significantly different for those exposed in childhood and for those exposed in adulthood, if adjustment is made for the effects on the relative risk of age at exposure. For those irradiated in childhood, there is a statistically significant annual reduction of 5.8% (95% Cl 2.8, 8.9) in excess relative risk, and there are no strong indications of inter-cohort heterogeniety in the speed of reduction of relative risk. After adjustment for the effects of age at exposure, there is a significant annual reduction of 3.6% (95% Cl 1.6, 5.6) in excess relative risk in all age-at-exposure groups. There are significant reductions of 5.2% (95% Cl 3.7, 6.8) in excess relative risk per year of age at exposure. There are statistically significant (P = 0.04) interactions between the exponential adjustments to the excess relative risk for age at exposure and time since exposure in the Japanese data, but no indications (P = 0.38) of such interactions when powers of time since exposure and attained age are used to adjust the excess relative risk, so that the fit of the model with power adjustments is to be preferred to that of the model with exponential adjustments. (author)

  12. Rectal dose variation during the course of image-guided radiation therapy of prostate cancer

    International Nuclear Information System (INIS)

    Chen Lili; Paskalev, Kamen; Xu Xiu; Zhu, Jennifer; Wang Lu; Price, Robert A.; Hu Wei; Feigenberg, Steven J.; Horwitz, Eric M.; Pollack, Alan; Charlie Ma, C.M.

    2010-01-01

    Background and purpose: To investigate the change in rectal dose during the treatment course for intensity-modulated radiotherapy (IMRT) of prostate cancer with image-guidance. Materials and methods: Twenty prostate cancer patients were recruited for this retrospective study. All patients have been treated with IMRT. For each patient, MR and CT images were fused for target and critical structure delineation. IMRT treatment planning was performed on the simulation CT images. Inter-fractional motion during the course of treatment was corrected using a CT-on-rails system. The rectum was outlined on both the original treatment plan and the subsequent daily CT images from the CT-on-rails by the same investigator. Dose distributions on these daily CT images were recalculated with the isocenter shifts relative to the simulation CT images using the leaf sequences/MUs based on the original treatment plan. The rectal doses from the subsequent daily CTs were compared with the original doses planned on the simulation CT using our clinical acceptance criteria. Results: Based on 20 patients with 139 daily CT sets, 28% of the subsequent treatment dose distributions did not meet our criterion of V 40 65 < 17%. The inter-fractional rectal volume variation is significant for some patients. Conclusions: Due to the large inter-fractional variation of the rectal volume, it is more favorable to plan prostate IMRT based on an empty rectum and deliver treatment to patients with an empty rectum. Over 70% of actual treatments showed better rectal doses than our clinical acceptance criteria. A significant fraction (27%) of the actual treatments would benefit from adaptive image-guided radiotherapy based on daily CT images.

  13. Variation and Grey GM(1, 1) Prediction of Melting Peak Temperature of Polypropylene During Ultraviolet Radiation Aging

    Science.gov (United States)

    Chen, K.; Y Zhang, T.; Zhang, F.; Zhang, Z. R.

    2017-12-01

    Grey system theory regards uncertain system in which information is known partly and unknown partly as research object, extracts useful information from part known, and thereby revealing the potential variation rule of the system. In order to research the applicability of data-driven modelling method in melting peak temperature (T m) fitting and prediction of polypropylene (PP) during ultraviolet radiation aging, the T m of homo-polypropylene after different ultraviolet radiation exposure time investigated by differential scanning calorimeter was fitted and predicted by grey GM(1, 1) model based on grey system theory. The results show that the T m of PP declines with the prolong of aging time, and fitting and prediction equation obtained by grey GM(1, 1) model is T m = 166.567472exp(-0.00012t). Fitting effect of the above equation is excellent and the maximum relative error between prediction value and actual value of T m is 0.32%. Grey system theory needs less original data, has high prediction accuracy, and can be used to predict aging behaviour of PP.

  14. Predictable variation of range-sizes across an extreme environmental gradient in a lizard adaptive radiation: evolutionary and ecological inferences.

    Directory of Open Access Journals (Sweden)

    Daniel Pincheira-Donoso

    Full Text Available Large-scale patterns of current species geographic range-size variation reflect historical dynamics of dispersal and provide insights into future consequences under changing environments. Evidence suggests that climate warming exerts major damage on high latitude and elevation organisms, where changes are more severe and available space to disperse tracking historical niches is more limited. Species with longer generations (slower adaptive responses, such as vertebrates, and with restricted distributions (lower genetic diversity, higher inbreeding in these environments are expected to be particularly threatened by warming crises. However, a well-known macroecological generalization (Rapoport's rule predicts that species range-sizes increase with increasing latitude-elevation, thus counterbalancing the impact of climate change. Here, I investigate geographic range-size variation across an extreme environmental gradient and as a function of body size, in the prominent Liolaemus lizard adaptive radiation. Conventional and phylogenetic analyses revealed that latitudinal (but not elevational ranges significantly decrease with increasing latitude-elevation, while body size was unrelated to range-size. Evolutionarily, these results are insightful as they suggest a link between spatial environmental gradients and range-size evolution. However, ecologically, these results suggest that Liolaemus might be increasingly threatened if, as predicted by theory, ranges retract and contract continuously under persisting climate warming, potentially increasing extinction risks at high latitudes and elevations.

  15. Variation of oxygen enhancement ratio with radiation dose studies using 8 MeV electron beam

    International Nuclear Information System (INIS)

    Yerol, Narayana; Nairy, Rajesha K.; Sanjeev, Ganesh

    2014-01-01

    The radiobiological effects can be modified by physical, chemical and biological factors. Oxygen is one of the best known modifiers, and the biological effects are greater in the presence of oxygen. Failure to achieve complete response following radiotherapy of large tumors is attributed to the presence of radio-resistant hypoxic cells; therefore clarifying the mechanism of the oxygen effect is important. In the present study, an attempt was made to quantify Oxygen Enhancement Ratio (OER) and variation of OER as a function of dose with experimental and theoretical formulations using Saccharomyces cerevisiae D7, X2180 and rad 52 and 8 MeV electron beam from Microtron accelerator. The single cell stationary-phase cultures were obtained by growing the cells in Yeast extract: Peptone: Dextrose (YEPD) (1%:2%:2%) medium for several generations in stationary phase to a density of approximately 3 x 10 8 cells mL -1 . Cells were washed thrice by centrifugation and re-suspended to a cell concentration of 1 x 10 8 cells mL -1 in a sterile polypropylene vial for irradiation. Hypoxic conditions were achieved by incubating the samples in air tight vials at 30℃ for 30 min prior to irradiation. For euoxic samples, a cell suspension of 1 x 10 6 cells mL -1 was prepared and was thoroughly aerated by mixing before irradiation. Treated and untreated samples were suitably diluted and plated in quadruplicate on YEPD agar medium. Plates were incubated for 2-3 days at 30℃ in dark and normal atmospheric conditions and the colonies were counted. The study confirmed that, the variation of OER with dose depends upon type of cell and repair proficiency of cells. For repair proficient cells OER value has been found to increase with dose, while remain constant for repair deficient cell lines. A theoretical model has been formulated to estimate OER values. The OER value varies from 1.51 to 2.53 for D7, 2.02 to 2.98 for X2180, and 2.58 for rad 52. (author)

  16. Quantitatively characterizing microstructural variations of skin tissues during ultraviolet radiation damaging process based on Mueller matrix polarimetry

    Science.gov (United States)

    Sheng, Wei; He, Honghui; Dong, Yang; Ma, Hui

    2018-02-01

    As one of the most fundamental features of light, polarization can be used to develop imaging techniques which can provide insight into the optical and structural properties of tissues. Especially, the Mueller matrix polarimetry is suitable to detect the changes in collagen and elastic fibres, which are the main compositions of skin tissue. Here we demonstrate a novel quantitative, non-contact and in situ technique to monitor the microstructural variations of skin tissue during ultraviolet radiation (UVR) induced photoaging based on Mueller matrix polarimetry. Specifically, we measure the twodimensional (2D) backscattering Mueller matrices of nude mouse skin samples, then calculate and analyze the Mueller matrix derived parameters during the skin photoaging and self-repairing processes. To induce three-day skin photoaging, the back skin of each mouse is irradiated with UVR (0.05J/cm2) for five minutes per day. After UVR, the microstructures of the nude mouse skin are damaged. During the process of UV damage, we measure the backscattering Mueller matrices of the mouse skin samples and examine the relationship between the Mueller matrix parameters and the microstructural variations of skin tissue quantitatively. The comparisons between the UVR damaged groups with and without sunscreens show that the Mueller matrix derived parameters are potential indicators for fibrous microstructure variation in skin tissue. The pathological examinations and Monte Carlo simulations confirm the relationship between the values of Mueller matrix parameters and the changes of fibrous structures. Combined with smart phones or wearable devices, this technique may have a good application prospect in the fields of cosmetics and dermatological health.

  17. Estimating hourly variation in photosynthetically active radiation across the UK using MSG SEVIRI data

    International Nuclear Information System (INIS)

    Pankaew, P; Milton, E J; Dash, J

    2014-01-01

    The amount of photosynthetically active radiation (PAR) reaching the Earth's surface is a key input variable in most gross primary productivity models. However, poor representation of PAR due to large pixel size or limited temporal sampling is one of the main sources of uncertainty in such models. This paper presents a method to estimate PAR at up to 1 km spatial resolution at a regional to global scale. The method uses broadband radiance data (400–1100nm) and per-pixel estimates of relative cloud cover from a geostationary satellite to estimate the amount of PAR reaching the Earth's surface at high spatial and temporal resolution (1–2 km and hourly). The method was validated using data from 54 pyranometers located at sites across the UK. Hourly averaged PAR over the range 400–1400 μmol m −2 s −1 was estimated with a mean bias error = 5.01 μmol m −2 s −1 (R 2 = 0.87), providing a source of accurate data for high resolution models of gross primary productivity

  18. Variation of Human Hairiness: A Possible Adaptation to Solar Radiation and Melanin

    Directory of Open Access Journals (Sweden)

    Dhugga Amrita

    2014-07-01

    Full Text Available Many theories have been advanced to explain human hairlessness, however, there is no consensus. This study of 76 males observed that skin reflectance measuring skin colouration and melanin pigmentation correlated with hair size and follicle density. Individuals with a greater concentration of melanin within the superficial layer of the skin had a lower follicle density and smaller sizes of hairs. In contrast, individuals with a lower melanin concentration and lighter skin colour had a full range of hairiness. This leads to the suggestion that over the course of human evolution, high concentrations of melanin in consistently exposed to ultraviolet radiation areas developed first and that hair loss was a consequence of competition in the skin between melanin production and hair growth. Darker pigmented skin and lower follicle density are significantly correlated (R2=0.283; p<0.05. Individuals with darker skin had a mean of 4.91 follicles per cm2 whereas those with lighter skin reflectance had 11.20 follicles per cm2. This suggests that increased concentrations of melanin in the basal layer of the epidermis may limit hairiness by negatively influencing the skin's ability to produce hair.

  19. Latitude variation of the diffuse component of the mean energy gamma radiation

    International Nuclear Information System (INIS)

    Espirito Santo, C.M. do.

    1981-03-01

    For determining the diffuse component of gamma ray in the 15 to 75 MeV range arriving from near the galactic center, a digitized spark chamber was launched aboard two balloons from Resende, Brazil on 19 November and 3 December 1975. In each flight the detector reached an altitude of 2,2 g.cm - 2 . Based on these data, we obtained a diffuse gamma ray flux 6,0 x 10 - 5 , 2,0 x 10 - 5 , 4,6 x 10 - 6 and 1,3 x 10 - 6 photons/cm 2 .s.sterad.MeV at energies of 21, 36, 52 and 67 MeV respectively. These values give a power law spectrum with spectral index equal to - 3,3. The dependence of this radiation with the galactic latitude and longitude in the interval - 5 0 0 and 325 0 0 was also obtained. Finally, results obtained were compared with other experimenters' results. (Author) [pt

  20. Changes in radiation dose with variations in human anatomy: larger and smaller normal-stature adults.

    Science.gov (United States)

    Marine, Patrick M; Stabin, Michael G; Fernald, Michael J; Brill, Aaron B

    2010-05-01

    A systematic evaluation has been performed to study how specific absorbed fractions (SAFs) vary with changes in adult body size, for persons of different size but normal body stature. A review of the literature was performed to evaluate how individual organ sizes vary with changes in total body weight of normal-stature individuals. On the basis of this literature review, changes were made to our easily deformable reference adult male and female total-body models. Monte Carlo simulations of radiation transport were performed; SAFs for photons were generated for 10th, 25th, 75th, and 90th percentile adults; and comparisons were made to the reference (50th) percentile SAF values. Differences in SAFs for organs irradiating themselves were between 0.5% and 1.0%/kg difference in body weight, from 15% to 30% overall, for organs within the trunk. Differences in SAFs for organs outside the trunk were not greater than the uncertainties in the data and will not be important enough to change calculated doses. For organs irradiating other organs within the trunk, differences were significant, between 0.3% and 1.1%/kg, or about 8%-33% overall. The differences are interesting and can be used to estimate how different patients' dosimetry might vary from values reported in standard dose tables.

  1. Observer variation in target volume delineation of lung cancer related to radiation oncologist-computer interaction: A 'Big Brother' evaluation

    International Nuclear Information System (INIS)

    Steenbakkers, Roel J.H.M.; Duppen, Joop C.; Fitton, Isabelle; Deurloo, Kirsten E.I.; Zijp, Lambert; Uitterhoeve, Apollonia L.J.; Rodrigus, Patrick T.R.; Kramer, Gijsbert W.P.; Bussink, Johan; Jaeger, Katrien De; Belderbos, Jose S.A.; Hart, Augustinus A.M.; Nowak, Peter J.C.M.; Herk, Marcel van; Rasch, Coen R.N.

    2005-01-01

    Background and purpose: To evaluate the process of target volume delineation in lung cancer for optimization of imaging, delineation protocol and delineation software. Patients and methods: Eleven radiation oncologists (observers) from five different institutions delineated the Gross Tumor Volume (GTV) including positive lymph nodes of 22 lung cancer patients (stages I-IIIB) on CT only. All radiation oncologist-computer interactions were recorded with a tool called 'Big Brother'. For each radiation oncologist and patient the following issues were analyzed: delineation time, number of delineated points and corrections, zoom levels, level and window (L/W) settings, CT slice changes, use of side windows (coronal and sagittal) and software button use. Results: The mean delineation time per GTV was 16 min (SD 10 min). The mean delineation time for lymph node positive patients was on average 3 min larger (P=0.02) than for lymph node negative patients. Many corrections (55%) were due to L/W change (e.g. delineating in mediastinum L/W and then correcting in lung L/W). For the lymph node region, a relatively large number of corrections was found (3.7 corr/cm 2 ), indicating that it was difficult to delineate lymph nodes. For the tumor-atelectasis region, a relative small number of corrections was found (1.0 corr/cm 2 ), indicating that including or excluding atelectasis into the GTV was a clinical decision. Inappropriate use of L/W settings was frequently found (e.g. 46% of all delineated points in the tumor-lung region were delineated in mediastinum L/W settings). Despite a large observer variation in cranial and caudal direction of 0.72 cm (1 SD), the coronal and sagittal side windows were not used in 45 and 60% of the cases, respectively. For the more difficult cases, observer variation was smaller when the coronal and sagittal side windows were used. Conclusions: With the 'Big Brother' tool a method was developed to trace the delineation process. The differences between

  2. Radiation induced variation in potato for tolerance to salinity using tissue culture technique

    International Nuclear Information System (INIS)

    Sharabash, M.T.

    2001-01-01

    Meristem-tips of potato (Solanum tuberosum) cv. 'Diamant', obtained from tuber sprouts, were cultured on MS medium, and multiplied into plantlets through micropropagation. To induce variation for salt tolerance, the obtained plantlets were irradiated with 0, 20, and 40 Gy gamma rays at 27.7 rad/sec. Irradiated plantlets were cut into single nodes and cultured on MS medium, supplemented with 2000 and 4000 ppm NaCI. Salt tolerant plantlets were transferred for tuberization on MS liquid medium supplemented with the same concentration of NaCI. Micro-tubers, collected after 6 weeks of culture, had fresh weight between 0.03 to 0.3 g. Mini-tubers were obtained by planting micro-tubers in 25 cm pots under insect proof greenhouse. Mini-tuber number per plant ranged from 3 to 6, and the mini-tuber weight ranged from 0.5-3.0 g, depending upon the treatment. Further studies are in progress to produce conventional tubers under salinity stress from the promising variants, specially those tolerant to 4000 ppm, and to assure the stability of the obtained variants. (author)

  3. Normal variation in thermal radiated temperature in cattle: implications for foot-and-mouth disease detection

    Directory of Open Access Journals (Sweden)

    Gloster John

    2011-11-01

    Full Text Available Abstract Background Thermal imagers have been used in a number of disciplines to record animal surface temperatures and as a result detect temperature distributions and abnormalities requiring a particular course of action. Some work, with animals infected with foot-and-mouth disease virus, has suggested that the technique might be used to identify animals in the early stages of disease. In this study, images of 19 healthy cattle have been taken over an extended period to determine hoof and especially coronary band temperatures (a common site for the development of FMD lesions and eye temperatures (as a surrogate for core body temperature and to examine how these vary with time and ambient conditions. Results The results showed that under UK conditions an animal's hoof temperature varied from 10°C to 36°C and was primarily influenced by the ambient temperature and the animal's activity immediately prior to measurement. Eye temperatures were not affected by ambient temperature and are a useful indicator of core body temperature. Conclusions Given the variation in temperature of the hooves of normal animals under various environmental conditions the use of a single threshold hoof temperature will be at best a modest predictive indicator of early FMD, even if ambient temperature is factored into the evaluation.

  4. Enclosed belts in the ascendancy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-03-15

    Although there will always be a place for traditional overland belt conveyors, enclosed belt systems are increasingly being specified where environmental protection assumes high priority or where there is a need to protect material from the weather. The article reports on recent conveyor projects such as: an MRC cable Belt in a 6.4 km system to carry coal in the Appalachian Mountains; a $40 m contract awarded to FL Smidth to supply an integrated coal handling system to LILIAMA in Vietnam and other contracts to handle coal for India's Coastal Gujarat Power; and a contract awarded to Bateman Engineered Technologies to supply a 7 km Japan Pipe Conveyor for a coal power station in Brazil. 3 photos.

  5. Study of seasonal variation of the gamma radiation at Praia da Areia Preta, Guarapari, Espirito Santo, Brazil: radiometry and risk analysis

    International Nuclear Information System (INIS)

    Moura, Jorge Costa de

    2003-01-01

    The objective of this work is the study of the natural gamma radiation at the Areia Preta Beach (APB) in Guarapari, state of Espirito Santo, Brazil. The level of this radiation is dependent on the concentration of the radioactive mineral monazite in the sand. Probable risks of the exposure to gamma radiation at the APB were evaluated by the preliminary environmental risk analysis technique. For this purpose were conducted two annual sets monitoring gamma radiation in the APB every two months and so, acquired the seasonal variation of the radioactive levels. Additional/y was investigated the granulometry of the heavy mineral fraction and also carried out electronic microscopic scanning and radiometric age dating of the monazites of the APB, the mineral separation by magnetic susceptibility, and the mineralogic determination of the sediment. In order to gain a more complete picture of the seasonal variation, and, consequently, of the risk of exposure to ionizing radiation at the APB, the radiometric variation was also studied at some other beaches in the same region. The results indicate that the highest radiometric values are measured in summer and the lowest in winter. The radiometric dating of the monazites from the APB revealed the ages of 475 and 530 Ma. The Preliminary Hazard Analysis indicates a minimum risk of excessive radioactive exposition. It would take a period of approximately 870 years of a beach fully crowded to result in one case of bad consequences due to exposure to gamma radiation. (author)

  6. Detection of embedded radiation sources using temporal variation of gamma spectral data.

    Energy Technology Data Exchange (ETDEWEB)

    Shokair, Isaac R.

    2011-09-01

    Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the isotopes present in a measurement. For low energy resolution detectors, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the isotopes present in the measurement. When many isotopes are present it is difficult to make the correct identification and this process often requires many trial solutions by highly skilled spectroscopists. This report investigates the potential of a new analysis method which uses spatial/temporal information from multiple low energy resolution measurements to test the hypothesis of the presence of a target spectrum of interest in these measurements without the need to identify all the other isotopes present. This method is referred to as targeted principal component analysis (TPCA). For radiation portal monitor applications, multiple measurements of gamma spectra are taken at equally spaced time increments as a vehicle passes through the portal and the TPCA method is directly applicable to this type of measurement. In this report we describe the method and investigate its application to the problem of detection of a radioactive localized source that is embedded in a distributed source in the presence of an ambient background. Examples using simulated spectral measurements indicate that this method works very well and has the potential for automated analysis for RPM applications. This method is also expected to work well for isotopic detection in the presence of spectrally and spatially varying backgrounds as a result of vehicle-induced background suppression. Further work is needed to include effects of shielding, to understand detection limits, setting of thresholds, and to estimate false positive probability.

  7. Spatial Representativeness of Surface-Measured Variations of Downward Solar Radiation

    Science.gov (United States)

    Schwarz, M.; Folini, D.; Hakuba, M. Z.; Wild, M.

    2017-12-01

    When using time series of ground-based surface solar radiation (SSR) measurements in combination with gridded data, the spatial and temporal representativeness of the point observations must be considered. We use SSR data from surface observations and high-resolution (0.05°) satellite-derived data to infer the spatiotemporal representativeness of observations for monthly and longer time scales in Europe. The correlation analysis shows that the squared correlation coefficients (R2) between SSR times series decrease linearly with increasing distance between the surface observations. For deseasonalized monthly mean time series, R2 ranges from 0.85 for distances up to 25 km between the stations to 0.25 at distances of 500 km. A decorrelation length (i.e., the e-folding distance of R2) on the order of 400 km (with spread of 100-600 km) was found. R2 from correlations between point observations and colocated grid box area means determined from satellite data were found to be 0.80 for a 1° grid. To quantify the error which arises when using a point observation as a surrogate for the area mean SSR of larger surroundings, we calculated a spatial sampling error (SSE) for a 1° grid of 8 (3) W/m2 for monthly (annual) time series. The SSE based on a 1° grid, therefore, is of the same magnitude as the measurement uncertainty. The analysis generally reveals that monthly mean (or longer temporally aggregated) point observations of SSR capture the larger-scale variability well. This finding shows that comparing time series of SSR measurements with gridded data is feasible for those time scales.

  8. Explaining state-to-state differences in seat belt use : an analysis of socio-demographic variables.

    Science.gov (United States)

    2011-02-01

    "Despite the extensive evidence about the benefits of seat belt use, there is a great deal of variation in use within the US. For example, the national average for seat belt use in 2009 was 84 percent while the state-level averages ranged from 68 per...

  9. Rules of parotid gland dose variations and shift during intensity modulated radiation therapy for nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Wang, Wei; Yang, Haihua; Mi, Yucheng; Hu, Wei; Ding, Weijun; Xie, Youyou; Cai, Yujie; Chen, Xiaofeng

    2015-01-01

    To determine the position and dose delivery changes rules of parotid gland (PG) during the course of intensity modulated radiation therapy (IMRT) in nasopharyngeal carcinoma patients (NPC). One hundred and forty one competed tomography (CT) images from 47 NPC patients (three images for each patient were acquired before treatment, at the 15th and 25th fraction during the treatment) who underwent radical IMRT were selected for this study. A total of 70-76Gy at 2.12–2.3 Gy/fraction/d was given to the GTVnx in 33 fractions. The distances between the lateral/medial aspects of PG and midline (DLM and DMM) at the level of odontoid process were measured. The dose differences between plan and actual delivery were calculated. The volume reductions of PGs between fractions 15 and 25 were larger than those in the first 15 fractions (4.68 ± 3.23 cc vs. 2.46 ± 4.55 cc for the right PG and 5.96 ± 2.99 cc vs. 2.06 ± 2.99 cc for the left PG). However, the percentage of gland volume receiving ≥30 Gy (V30) of bilateral PGs decreased more significantly in the first 15 fractions than that between fractions 15 and 25 (5.61 ± 16.04% vs. 1.14 ± 21.54% for the right PG and 6.87 ± 15.58% vs. 0.81 ± 15.94% for the left PG). The gross tumor volume of the nasopharynx (GTVnx) decreased more significantly in the first 15 fractions than that between the 15th and 25th fraction (8.23 ± 13.61 cc vs. 3.30 ± 8.09 cc). The DMM of ipsilateral PGs reduced in the first 15 fractions (0.80 ± 2.96 mm) but increased between fraction 15 and 25 (−2.19 ± 3.96 mm). While ipsilateral PG shifted into target volume but shifted out target volume between fraction 15 and 25. Parotid glands V30 was correlated with GTVnx, GTVnx reduction and DMM reduction (p < 0.01). Our results indicate that the reduction of GTVnx leads to the positional change of the parotid gland, which results in more significant dose change of the parotid gland in the first 15 fractions than that between fraction 15 and 25

  10. The relationship between temporal variation of hypoxia, polarographic measurements and predictions of tumour response to radiation

    Science.gov (United States)

    Toma-Dasu, Iuliana; Dasu, Alexandru; Karlsson, Mikael

    2004-10-01

    The polarographic oxygen sensor is one of the most used devices for in vivo measurements of oxygen and many other measurement techniques for measuring tumour hypoxia are correlated with electrode measurements. Little is known however about the relationship between electrode measurements and the real tissue oxygenation. This paper investigates the influence of the temporal change of the hypoxic pattern on the electrode measurements and the tumour response. Electrode measurements and tumour response were simulated using a computer program that allows both the calculation of the tissue oxygenation with respect to the two types of hypoxia that might arise in tumours and the virtual insertion of the electrode into the tissue. It was therefore possible to control the amount of each type of hypoxia in order to investigate their influence on the measurement results. Tissues with several vascular architectures ranging from well oxygenated to poorly oxygenated were taken into consideration as might be seen in practice. The influence of the electrode measurements on the treatment outcome was estimated by calculating the tumour control probability for the tumours characterized either by the real or by the measured tumour oxygenation. We have simulated electrode oxygen measurements in different types of tissues, covering a wide range of tumour oxygenations. The results of the simulations showed that the measured distribution depends on the details of the vascular network and not on the type of hypoxia. We have also simulated the effects of the temporal change of the acute hypoxic pattern due to the opening and the closure of different blood vessels during a full fractionated treatment. The results of this simulation suggested that the temporal variation of the hypoxic pattern does not lead to significantly different results for the electrode measurements or the predicted tumour control probabilities. In conclusion, it was found that the averaging effect of the electrode leads

  11. Characteristic of the radiation field in low earth orbit and in deep space

    International Nuclear Information System (INIS)

    Reitz, Guenther

    2008-01-01

    The radiation exposure in space by cosmic radiation can be reduced through careful mission planning and constructive measures as example the provision of a radiation shelter, but it cannot be completely avoided. The reason for that are the extreme high energies of particles in this field and the herewith connected high penetration depth in matter. For missions outside the magnetosphere ionizing radiation is recognized as the key factor through its impact on crew health and performance. In absence of sporadic solar particle events the radiation exposure in Low Earth orbit (LEO) inside Spacecraft is determined by the galactic cosmic radiation (protons and heavier ions) and by the protons inside the South Atlantic Anomaly (SAA), an area where the radiation belt comes closer to the earth surface due to a displacement of the magnetic dipole axes from the Earth's center. In addition there is an albedo source of neutrons produced as interaction products of the primary galactic particles with the atoms of the earth atmosphere. Outside the spacecraft the dose is dominated by the electrons of the horns of the radiation belt located at about 60 latitude in Polar Regions. The radiation field has spatial and temporal variations in dependence of the Earth magnetic field and the solar cycle. The complexity of the radiation field inside a spacecraft is further increased through the interaction of the high energy components with the spacecraft shielding material and with the body of the astronauts. In interplanetary missions the radiation belt will be crossed in a couple of minutes and therefore its contribution to their radiation exposure is quite small, but subsequently the protection by the Earth magnetic field is lost, leaving only shielding measures as exposure reduction means. The report intends to describe the radiation field in space, the interaction of the particles with the magnetic field and shielding material and give some numbers on the radiation exposure in low earth

  12. Characteristic of the radiation field in low Earth orbit and in deep space.

    Science.gov (United States)

    Reitz, Guenther

    2008-01-01

    The radiation exposure in space by cosmic radiation can be reduced through careful mission planning and constructive measures as example the provision of a radiation shelter, but it cannot be completely avoided. The reason for that are the extreme high energies of particles in this field and the herewith connected high penetration depth in matter. For missions outside the magnetosphere ionizing radiation is recognized as the key factor through its impact on crew health and performance. In absence of sporadic solar particle events the radiation exposure in Low Earth orbit (LEO) inside Spacecraft is determined by the galactic cosmic radiation (protons and heavier ions) and by the protons inside the South Atlantic Anomaly (SAA), an area where the radiation belt comes closer to the earth surface due to a displacement of the magnetic dipole axes from the Earth's center. In addition there is an albedo source of neutrons produced as interaction products of the primary galactic particles with the atoms of the earth atmosphere. Outside the spacecraft the dose is dominated by the electrons of the horns of the radiation belt located at about 60" latitude in Polar Regions. The radiation field has spatial and temporal variations in dependence of the Earth magnetic field and the solar cycle. The complexity of the radiation field inside a spacecraft is further increased through the interaction of the high energy components with the spacecraft shielding material and with the body of the astronauts. In interplanetary missions the radiation belt will be crossed in a couple of minutes and therefore its contribution to their radiation exposure is quite small, but subsequently the protection by the Earth magnetic field is lost, leaving only shielding measures as exposure reduction means. The report intends to describe the radiation field in space, the interaction of the particles with the magnetic field and shielding material and give some numbers on the radiation exposure in low earth

  13. Spatial and temporal variation in radiation exposure of amphibians - Implications for environmental risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Stark, K. [Stockholm University (Sweden)

    2014-07-01

    Although amphibians are threatened world-wide, many amphibian species are protected in national legislation. Thus, amphibians need special attention in many environmental risk assessments for releases of contaminants such as radionuclides. In fact, amphibians' ecology and physiology (including, for example, a complex life-cycle with both aquatic and terrestrial life stages, and a thin skin) makes them sensitive to radiation exposure. In current dose models for wildlife, homogenous distribution of radionuclides in soil is assumed. However, soils are heterogeneous environments and radionuclide contamination can be very unevenly distributed. As a consequence, bioaccumulation of radionuclides in biota may vary on a local scale. Specifically, organisms' spatial location and movement within habitats may affect both their external and internal exposure pattern to radionuclides. Therefore, measuring the spatial location of individual amphibians within ecosystems and understanding why they use these different locations is essential for predicting potential effects of released radionuclides on these populations. The aim of this study was to investigate amphibians' spatial distribution in a {sup 137}Cs contaminated wetland area and their body content of {sup 137}Cs at the beginning and end of the summer period. The study site was a wetland nature reserve called Bladmyra near Gaevle in the central-eastern part of Sweden. This area received fallout of {sup 137}Cs after the Chernobyl accident in 1986. This study measured the spatial distributions of two amphibian species (Rana arvalis and Bufo bufo) with Passive Integrated Transponder (PIT) tags in a mark-and-recapture study during 2012-2014. In addition, {sup 137}Cs body content in the two species was measured by whole body counting in spring and autumn of 2013. The results showed differences between years in how marked animals used the study area: More individuals stayed in a small area during 2012 than in 2013

  14. 30 CFR 77.1107 - Belt conveyors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Belt conveyors. 77.1107 Section 77.1107 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY... § 77.1107 Belt conveyors. Belt conveyors in locations where fire would create a hazard to personnel...

  15. Grinding Glass Disks On A Belt Sander

    Science.gov (United States)

    Lyons, James J., III

    1995-01-01

    Small machine attached to table-top belt sander makes possible to use belt sander to grind glass disk quickly to specified diameter within tolerance of about plus or minus 0.002 in. Intended to be used in place of production-shop glass grinder. Held on driveshaft by vacuum, glass disk rotated while periphery ground by continuous sanding belt.

  16. 36 CFR 4.15 - Safety belts.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Safety belts. 4.15 Section 4... TRAFFIC SAFETY § 4.15 Safety belts. (a) Each operator and passenger occupying any seating position of a motor vehicle in a park area will have the safety belt or child restraint system properly fastened at...

  17. 14 CFR 31.63 - Safety belts.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Safety belts. 31.63 Section 31.63 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.63 Safety belts. (a) There must be a safety belt...

  18. 14 CFR 27.1413 - Safety belts.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Safety belts. 27.1413 Section 27.1413 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Safety Equipment § 27.1413 Safety belts. Each safety belt...

  19. 46 CFR 169.723 - Safety belts.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Safety belts. 169.723 Section 169.723 Shipping COAST... Control, Miscellaneous Systems, and Equipment § 169.723 Safety belts. Each vessel must carry a harness type safety belt conforming to Offshore Racing Council (ORC) standards for each person on watch or...

  20. TEMPORAL AND SPATIAL VARIATION IN SOLAR RADIATION AND PHOTO-ENHANCED TOXICITY RISKS OF SPILLED OIL IN PRINCE WILLIAM SOUND, ALASKA

    Science.gov (United States)

    Solar irradiance (W/m2) and downwelling diffuse attenuation coefficients (Kd; m-1) were determined in several locations in Prince William Sound, Alaska, USA, between April 2003 and December 2005 to assess temporal and spatial variation in solar radiation and the risks of photoenh...

  1. Using the Atmospheric Radiation Measurement (ARM) Datasets to Evaluate Climate Models in Simulating Diurnal and Seasonal Variations of Tropical Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hailong [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Burleyson, Casey D. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Ma, Po-Lun [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Fast, Jerome D. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Rasch, Philip J. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington

    2018-04-01

    We use the long-term Atmospheric Radiation Measurement (ARM) datasets collected at the three Tropical Western Pacific (TWP) sites as a tropical testbed to evaluate the ability of the Community Atmosphere Model (CAM5) to simulate the various types of clouds, their seasonal and diurnal variations, and their impact on surface radiation. We conducted a series of CAM5 simulations at various horizontal grid spacing (around 2°, 1°, 0.5°, and 0.25°) with meteorological constraints from reanalysis. Model biases in the seasonal cycle of cloudiness are found to be weakly dependent on model resolution. Positive biases (up to 20%) in the annual mean total cloud fraction appear mostly in stratiform ice clouds. Higher-resolution simulations do reduce the positive bias in the frequency of ice clouds, but they inadvertently increase the negative biases in convective clouds and low-level liquid clouds, leading to a positive bias in annual mean shortwave fluxes at the sites, as high as 65 W m-2 in the 0.25° simulation. Such resolution-dependent biases in clouds can adversely lead to biases in ambient thermodynamic properties and, in turn, feedback on clouds. Both the CAM5 model and ARM observations show distinct diurnal cycles in total, stratiform and convective cloud fractions; however, they are out-of-phase by 12 hours and the biases vary by site. Our results suggest that biases in deep convection affect the vertical distribution and diurnal cycle of stratiform clouds through the transport of vapor and/or the detrainment of liquid and ice. We also found that the modelled gridmean surface longwave fluxes are systematically larger than site measurements when the grid that the ARM sites reside in is partially covered by ocean. The modeled longwave fluxes at such sites also lack a discernable diurnal cycle because the ocean part of the grid is warmer and less sensitive to radiative heating/cooling compared to land. Higher spatial resolution is more helpful is this regard. Our

  2. High cloud variations with surface temperature from 2002 to 2015: Contributions to atmospheric radiative cooling rate and precipitation changes

    Science.gov (United States)

    Liu, Run; Liou, Kuo-Nan; Su, Hui; Gu, Yu; Zhao, Bin; Jiang, Jonathan H.; Liu, Shaw Chen

    2017-05-01

    The global mean precipitation is largely constrained by atmospheric radiative cooling rates (Qr), which are sensitive to changes in high cloud fraction. We investigate variations of high cloud fraction with surface temperature (Ts) from July 2002 to June 2015 and compute their radiative effects on Qr using the Fu-Liou-Gu plane-parallel radiation model. We find that the tropical mean (30°S-30°N) high cloud fraction decreases with increasing Ts at a rate of about -1.0 ± 0.34% K-1 from 2002 to 2015, which leads to an enhanced atmospheric cooling around 0.86 W m-2 K-1. On the other hand, the northern midlatitudes (30°N-60°N) high cloud fraction increases with surface warming at a rate of 1.85 ± 0.65% K-1 and the near-global mean (60°S-60°N) high cloud fraction shows a statistically insignificant decreasing trend with increasing Ts over the analysis period. Dividing high clouds into cirrus, cirrostratus, and deep convective clouds, we find that cirrus cloud fraction increases with surface warming at a rate of 0.32 ± 0.11% K-1 (0.01 ± 0.17% K-1) for the near-global mean (tropical mean), while cirrostratus and deep convective clouds decrease with surface warming at a rate of -0.02 ± 0.18% K-1 and -0.33 ± 0.18% K-1 for the near-global mean and -0.64 ± 0.23% K-1 and -0.37 ± 0.13% K-1 for the tropical mean, respectively. High cloud fraction response to feedback to Ts accounts for approximately 1.9 ± 0.7% and 16.0 ± 6.1% of the increase in precipitation per unit surface warming over the period of 2002-2015 for the near-global mean and the tropical mean, respectively.

  3. Variation of radiation sensitivity of Friend Erythroleukemia cells cultured in the presence of the differentiation inducer DMSO

    International Nuclear Information System (INIS)

    Einspenner, M.; Boulton, J.E.; Borsa, J.

    1984-01-01

    Differentiation of Friend erythroleukemia cells (FELC) was induced with 1.5% dimethyl sulfoxide (DMSO) in the culture medium. Cell growth, erythroid differentiation, and radiosensitivity of the proliferative capacity of the cells were measured and compared to a noninduced control culture of identical age. Induced cells first appeared on Day 2 after DMSO addition, and increased to a maximum of 80 to 90% of the cell population on Day 5, whereas in the control culture, induction was less than 2% of the cells. Radiosensitivity of the cells in the induced culture relative to that of cells in the control culture, showed an age-dependent variation. On days 1 and 2 after DMSO addition, the cells in the induced culture were less radiosensitive than those in the control culture. At later times, this relationship was reversed, and between days 3 and 5 the clonable cells in the induced culture were less radiosensitive than those in the control culture. These results suggest that the metabolic events associated with commitment of FELC to differentiate affect their ability to cope with the radiation-induced lesions underlying the loss of division capacity

  4. Palliative radiation for vertebral metastases: the effect of variation in prescription parameters on the dose received at depth

    International Nuclear Information System (INIS)

    Barton, Rachael; Robinson, Graham; Gutierrez, Eric; Kirkbride, Peter; McLean, Michael

    2002-01-01

    Purpose: To assess the effect of prescription parameters on the dose received by the spine during palliative radiotherapy. Methods and Materials: In a survey, members of the Canadian Association of Radiation Oncologists were asked to define their prescription parameters for vertebral metastases. The depth of the spinal canal and vertebral body at 8 spinal levels was measured in 20 magnetic resonance imaging studies (MRIs). Survey results were applied to the measurements to assess the dose received at depth. The depth of spinal structures assessed at simulation and by diagnostic imaging was compared. Results: Prescriptions were most commonly to D max 3 cm or 5 cm using 60 Co-6MV photons delivering 8-30 Gy in 1-10 fractions. Mean depths from MRI were: posterior spinal canal, 5.5 cm; anterior spinal canal, 6.9 cm; and anterior vertebral body, 9.6 cm. Application of the prescription parameters from the survey to these measurements showed a wide range in the dose at depth with variation in technique. Depths measured at simulation correlated well with diagnostic imaging. Conclusion: The spinal canal and vertebral body lie >5 cm beneath the skin, and the dose received varies by up to 50% with changes in prescription depth. We suggest a suitable prescription point for vertebral metastases and a method for determining this at simulation

  5. Effects of sea surface temperature, cloud radiative and microphysical processes, and diurnal variations on rainfall in equilibrium cloud-resolving model simulations

    International Nuclear Information System (INIS)

    Jiang Zhe; Li Xiao-Fan; Zhou Yu-Shu; Gao Shou-Ting

    2012-01-01

    The effects of sea surface temperature (SST), cloud radiative and microphysical processes, and diurnal variations on rainfall statistics are documented with grid data from the two-dimensional equilibrium cloud-resolving model simulations. For a rain rate of higher than 3 mm·h −1 , water vapor convergence prevails. The rainfall amount decreases with the decrease of SST from 29 °C to 27 °C, the inclusion of diurnal variation of SST, or the exclusion of microphysical effects of ice clouds and radiative effects of water clouds, which are primarily associated with the decreases in water vapor convergence. However, the amount of rainfall increases with the increase of SST from 29 °C to 31 °C, the exclusion of diurnal variation of solar zenith angle, and the exclusion of the radiative effects of ice clouds, which are primarily related to increases in water vapor convergence. For a rain rate of less than 3 mm·h −1 , water vapor divergence prevails. Unlike rainfall statistics for rain rates of higher than 3 mm·h −1 , the decrease of SST from 29 °C to 27 °C and the exclusion of radiative effects of water clouds in the presence of radiative effects of ice clouds increase the rainfall amount, which corresponds to the suppression in water vapor divergence. The exclusion of microphysical effects of ice clouds decreases the amount of rainfall, which corresponds to the enhancement in water vapor divergence. The amount of rainfall is less sensitive to the increase of SST from 29 °C to 31 °C and to the radiative effects of water clouds in the absence of the radiative effects of ice clouds. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  6. Spectroscopical studies of impurities in the belt pinch HECTOR

    International Nuclear Information System (INIS)

    Singethan, J.

    1981-04-01

    In this paper UV-line-intensity measurements of impurities are presented, which have been performed in the belt-pinch HECTOR. From the line-intensities impurity concentrations and information on the radiation losses is be obtained. At temperatures below 100 eV, the energy loss due to line emission of oxygen and carbon impurities is one of the most important electron energy loss mechanisms. Thus the measurement and calculation of the radiation losses is of particular relevance. Furthermore the electron temperature time dependence can be obtained by comparing the line intensity time dependence with the solution of the respective rate equations. (orig./HT) [de

  7. Variations of radiation intensity as a function of position in radiation field of a mammographic unit of 760 mm SID with Mo anode and 20 μm Mo added filter

    International Nuclear Information System (INIS)

    Noriah Jamal

    2001-01-01

    There are many effects that contribute to radiation field nonuniformity in mammography, including the heel effect and shorter source to image distance (SID), inverse square law and different photon path lengths through various attenuating media (the x-ray tube beryllium window, the added filter, the mirror, and the compression paddle) throughout the field. Variations of radiation intensity was investigated as a function of position in the radiation field (with compression paddle in place)of a mammographic unit in 760 mm SID with Mo anode and 20 μm Mo added filter. Reduction in radiation intensity along central axis of up to 19.40%, 19.13% and 19.34% were noted at 24, 26 and 28 kVp respectively. Radiation intensity also drops off to the left and right of the central axis. As a function of position in the field, we also found that the variations of optical density correlate well with the measured radiation intensity changes. (Author)

  8. Conveyor belt nuclear weighing machine

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    In many industries the flow of materials on conveyor belts must be measured and controlled. Electromechanical weighing devices have high accuracy but are complicated and expensive to install and maintain. For many applications the nuclear weighing machine has sufficient accuracy but is considerably simpler, cheaper and more robust and is easier to maintain. The rating and performance of a gamma ray balance on the mar ket are detailed. (P.G.R.)

  9. Impacts of diurnal variation of ultraviolet-B and photosynthetically active radiation on phycobiliproteins of the hot-spring cyanobacterium Nostoc sp. strain HKAR-2.

    Science.gov (United States)

    Kannaujiya, Vinod K; Sinha, Rajeshwar P

    2017-01-01

    The effects of diurnal variation of photosynthetically active radiation (PAR; 400-700 nm) and ultraviolet-B (UV-B; 280-315 nm) radiation on phycobiliproteins (PBPs) and photosynthetic pigments (PP) have been studied in the hot-spring cyanobacterium Nostoc sp. strain HKAR-2. The variations in PBPs and PP were monitored by alternating light and dark under PAR, UV-B, and PAR + UV-B radiations over a period of 25 h. There was a decline in the amount of Chl a and PBPs during light periods of UV-B and PAR + UV-B and an increase during dark periods showing a circadian rhythm by destruction and resynthesis of pigment-protein complex. However, a marked induction in carotenoids was recorded during light periods of the same radiations. Moreover, the ratio of Chl a/PE and Chl a/PC was increased in dark periods showing the resynthesis of bleached Chl a. The wavelength shift in emission fluorescence of PBPs toward shorter wavelengths further indicated the bleaching and destruction of PBPs during light periods. Oxidative damage upon exposure to PAR, UV-B, and PAR + UV-B was alleviated by induction of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). The studied cyanobacterium exhibits a significant increase in the activities of SOD, CAT, and APX upon exposure to UV-B and PAR + UV-B radiations. The results indicate that pigment-protein composition of Nostoc sp. stain HKAR-2 was significantly altered during diurnal variation of light/radiation, which might play an important role in optimization for their productivity in a particular cyanobacterium.

  10. Inter fractional dose variation during intensity-modulated radiation therapy for cervical cancer assessed by weekly CT evaluation

    International Nuclear Information System (INIS)

    Han, Youngyih; Shin, Eun Hyuk; Huh, Seung Jae; Lee, Jung Eun; Park, Won

    2006-01-01

    Purpose: To investigate the inter fractional dose variation of a small-bowel displacement system (SBDS)-assisted intensity-modulated radiation therapy (IMRT) for the treatment of cervical cancer. Methods: Four computed tomography (CT) scans were carried out in 10 patients who received radiotherapy for uterine cervical cancer. The initial CT was taken by use of the SBDS, before the beginning of radiotherapy, and 3 additional CT scans with the SBDS were done in subsequent weeks. IMRT was planned by use of the initial CT, and the subsequent images were fused with the initial CT set. Dose-volume histogram (DVH) changes of the targets (planning target volume [PTV] = clinical target volume [CTV] + 1.5 cm) and of the critical organs were evaluated after obtaining the volumes of each organ on 4 CT sets. Results: No significant differences were found in PTV volumes. Changes on the DVH of the CTVs were not significant, whereas DVH changes of the PTVs at 40% to 100% of the prescription dose level were significant (V 90% ; 2nd week: p = 0.0091, 3rd week: p = 0.0029, 4th week: p = 0.0050). The changes in the small-bowel volume included in the treatment field were significant. These were 119.5 cm 3 (range, 26.9-251.0 cm 3 ), 126 cm 3 (range, 38.3-336 cm 3 ), 161.9 cm 3 (range, 37.7-294.6 cm 3 ), and 149.1 cm 3 (range, 38.6-277.8 cm 3 ) at the 1st, 2nd, 3rd, and 4th weeks, respectively, and were significantly correlated with the DVH change in the small bowel, which were significant at the 3rd (V 80% ; p = 0.0230) and 4th (V 80% ; p = 0.0263) weeks. The bladder-volume change correlated to the large volume change (>20%) of the small-bowel volume. Conclusions: Significant DVH differences for the small bowel can result because of interfractional position variations, whereas the DVH differences of the CTV were not significant. Strict bladder-filling control and an accurate margin for the PTV, as well as image-guided position verification, are important to achieve the goal of IMRT

  11. Modeling of the outer electron belt during magnetic storms

    International Nuclear Information System (INIS)

    Desorgher, L.; Buehler, P.; Zehnder, A.; Daly, E.; Adams, L.

    1999-01-01

    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

  12. Individual variation in p53 and Cip1 expression profiles in normal human fibroblast strains following exposure to high-let radiation

    International Nuclear Information System (INIS)

    Carpenter, T.R.; Johnson, N.F.; Gilliland, F.D.

    1995-01-01

    Exposure to α-particles emitted by radon progeny appears to be the second-leading cause of lung cancer mortality. However, individual susceptibility to the carcinogenic effects of α-particles remains poorly characterized. Variation in susceptibility to cancer produced by certian classes of DNA-damaging chemicals is suspected to involve differences in metabolic activation and detoxication. Susceptibility to α-particle-induced cancer may involve variations in capacity or opportunity to repair DNA damage. Subtle variations in DNA repair capacity would more likely explain radon-related lung cancer susceptibility. The p53 tumor suppressor protein accumulates as a cellular response to DNA damage from ionizing radiation and regulates arrest in the G 1 portion of the cell cycle. Arrest in G 1 portion of the cell cycle. While upstream regulation of p53 protein stability is poorly understood, variations in the ability to accumulate p53 following DNA damage represent potential variations in lung cancer susceptibility related to radon progeny. Further, transcription of the cell-cycle regulatory gene Cip1 is regulated by p53 and increases following ionizing radiation. Therefore, variations in the expression of Cip1 following α-particle exposure may also be a susceptibility factor in radon-related lung cancers. The purpose of the present investigation was to measure p53 and Cip1 protein induction following α-particle exposure of fibroblast lines from nine individuals to determine if there were significant variations. The expression of Cip1 protein indicates the differences in response are biologically relevant

  13. Individual variation in p53 and Cip1 expression profiles in normal human fibroblast strains following exposure to high-let radiation

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, T.R.; Johnson, N.F.; Gilliland, F.D. [Univ. of New Mexico, Albuquerque, NM (United States)] [and others

    1995-12-01

    Exposure to {alpha}-particles emitted by radon progeny appears to be the second-leading cause of lung cancer mortality. However, individual susceptibility to the carcinogenic effects of {alpha}-particles remains poorly characterized. Variation in susceptibility to cancer produced by certian classes of DNA-damaging chemicals is suspected to involve differences in metabolic activation and detoxication. Susceptibility to {alpha}-particle-induced cancer may involve variations in capacity or opportunity to repair DNA damage. Subtle variations in DNA repair capacity would more likely explain radon-related lung cancer susceptibility. The p53 tumor suppressor protein accumulates as a cellular response to DNA damage from ionizing radiation and regulates arrest in the G{sub 1} portion of the cell cycle. Arrest in G{sub 1} portion of the cell cycle. While upstream regulation of p53 protein stability is poorly understood, variations in the ability to accumulate p53 following DNA damage represent potential variations in lung cancer susceptibility related to radon progeny. Further, transcription of the cell-cycle regulatory gene Cip1 is regulated by p53 and increases following ionizing radiation. Therefore, variations in the expression of Cip1 following {alpha}-particle exposure may also be a susceptibility factor in radon-related lung cancers. The purpose of the present investigation was to measure p53 and Cip1 protein induction following {alpha}-particle exposure of fibroblast lines from nine individuals to determine if there were significant variations. The expression of Cip1 protein indicates the differences in response are biologically relevant.

  14. Synchronous and Cogged Fan Belt Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dean, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Acosta, Jason [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    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.

  15. 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.

  16. Belt Conveyor Dynamic Characteristics and Influential Factors

    Directory of Open Access Journals (Sweden)

    Junxia Li

    2018-01-01

    Full Text Available This paper uses the Kelvin-Voigt viscoelastic model to establish the continuous dynamic equations for tail hammer tension belt conveyors. The viscoelastic continuity equations are solved using the generalized coordinate method. We analyze various factors influencing longitudinal vibration of the belt conveyor by simulation and propose a control strategy to limit the vibration. The proposed approach and control strategy were verified by several experimental researches and cases. The proposed approach provides improved accuracy for dynamic design of belt conveyors.

  17. Drive alive: teen seat belt survey program.

    Science.gov (United States)

    Burkett, Katie M; Davidson, Steve; Cotton, Carol; Barlament, James; Loftin, Laurel; Stephens, James; Dunbar, Martin; Butterfield, Ryan

    2010-08-01

    To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP), a theory-driven intervention built on highway safety best practices. The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was the use of incentives, such as gift cards, to promote teen seat belt use. The third component involved disincentives, such as increased police patrol and school policies. The fourth component was a programmatic intervention that focused on education and media coverage of the DAPP program. Eleven pre-intervention surveys and nine post-intervention surveys were conducted before and after the intervention. The pre- and post-intervention seat belt usage showed significant differences (p<0.0001). The average pre-intervention seat belt usage rate was 51.2%, while the average post-intervention rate was 74.5%. This represents a percentage point increase of 23.3 in seat belt use after the DAPP intervention. Based on seat belt observational surveys, the DAPP was effective in increasing seat belt use among rural high school teenagers. Utilizing a theory-based program that builds on existing best practices can increase the observed seat belt usage among rural high school students.

  18. Continuous Mass Measurement on Conveyor Belt

    Science.gov (United States)

    Tomobe, Yuki; Tasaki, Ryosuke; Yamazaki, Takanori; Ohnishi, Hideo; Kobayashi, Masaaki; Kurosu, Shigeru

    The continuous mass measurement of packages on a conveyor belt will become greatly important. In the mass measurement, the sequence of products is generally random. An interesting possibility of raising throughput of the conveyor line without increasing the conveyor belt speed is offered by the use of two or three conveyor belt scales (called a multi-stage conveyor belt scale). The multi-stage conveyor belt scale can be created which will adjust the conveyor belt length to the product length. The conveyor belt scale usually has maximum capacities of less than 80kg and 140cm, and achieves measuring rates of more than 150 packages per minute and more. The output signals from the conveyor belt scale are always contaminated with noises due to vibrations of the conveyor and the product to be measured in motion. In this paper an employed digital filter is of Finite Impulse Response (FIR) type designed under the consideration on the dynamics of the conveyor system. The experimental results on the conveyor belt scale suggest that the filtering algorithms are effective enough to practical applications to some extent.

  19. Condition-Based Conveyor Belt Replacement Strategy in Lignite Mines with Random Belt Deterioration

    Science.gov (United States)

    Blazej, Ryszard; Jurdziak, Leszek

    2017-12-01

    In Polish lignite surface mines, condition-based belt replacement strategies are applied in order to assure profitable refurbishment of worn out belts performed by external firms specializing in belt maintenance. In two of three lignite mines, staff asses belt condition subjectively during visual inspections. Only one mine applies specialized diagnostic device (HRDS) allowing objective magnetic evaluation of belt core condition in order to choose the most profitable moment for the dismantling of worn out belt segments from conveyors and sending them to the maintenance firm which provides their refurbishment. This article describes the advantages of a new diagnostic device called DiagBelt. It was developed at the Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology. Economic gains from its application are calculated for the lignite mine and for the belt maintenance firm, taking into account random life (durability) of new and reconditioned belts (after the 1st and the 2nd refurbishment). Recursive calculations for following years allow the estimation of the length and costs of replaced, reconditioned and purchased belts on an annual basis, while the use of the Monte Carlo method allows the estimation of their variability caused by random deterioration of belts. Savings are obtained due to better selection of moments (times) for the replacement of belt segments and die to the possibility to qualify worn out belts for refurbishment without the need to remove their covers. In effect, increased belt durability and lowered share of waste belts (which were not qualified for reconditioning) create savings which can quickly cover expenditures on new diagnostic tools and regular belt inspections in the mine.

  20. The impact of the year-on-year variation in the intensity of solar radiation on the energy intensity of low-energy and passive houses

    Directory of Open Access Journals (Sweden)

    Šubrt Roman

    2017-01-01

    Full Text Available Solar radiation is a significant segment of heat gains in the operation of buildings. The importance of this segment is highlighted by lowering the energy performance of buildings. The current condition of assessment considers the standard values of solar radiation but these are often very different from the fair values. In the contribution it draws attention to not only to on-year variation in solar fluctuations in the intensity of solar radiation and its significant long-term deviation from the standard values but also to the impact to energy building in reliance to its energy intensity. The attention will be focused also to different values in standards valid in the Czech Republic. This specification of energy assessment of buildings is not only necessary to approximate calculations of real state, but mainly because we can expect more disputes about if a building has declared calculating the parameters of a building with nearly zero-energy or passive house.

  1. Study of the temporal and spatial variation of climate and solar radiation in th metropolitan Phoenix area. Final technical progress report, July 1, 1977-June 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Durrenberger, R.W.

    1978-09-29

    The research performed was designed to identify spatial or temporal variation of any atmospheric parameters that might affect the operation of devices utilizing solar energy in the metropolitan Phoenix area. The first part of the research involved the analysis of all available solar and climatic data to determine their validity and comparability. For the standard climatic parameters, few difficulties were encountered, but the task of determining comparability of solar radiation data involved many pitfalls. It was concluded that most of the solar data acquired before January 1977 could not be used for purposes of identifying spatial variability. And, a year and a half of data does not represent a long enough period of time upon which to base sound conclusions about spatial and temporal variability of solar radiation in the metropolitan Phoenix region. The data currently available to us do not indicate any great variation of solar radiation in the metropolitan Phoenix area. However, any meaningful statements about spatial and temporal variability of solar radiation in the metropolitan Phoenix area must await the acquisition of additional data from well-calibrated equipment.

  2. Analysis of the variation of the attenuation curve in function of the radiation field size for k Vp X-ray beams using the MCNP-5C code

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Marco A.R., E-mail: marco@cetea.com.b, E-mail: marfernandes@fmb.unesp.b [Universidade Estadual Paulista Julio de Mesquita Filho (FMB/UNESP), Botucatu, SP (Brazil). Fac. de Medicina; Ribeiro, Victor A.B. [Universidade Estadual Paulista Julio de Mesquita Filho (IBB/UNESP), Botucatu, SP (Brazil). Inst. de Biociencias; Viana, Rodrigo S.S.; Coelho, Talita S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The paper illustrates the use of the Monte Carlo method, MCNP-5C code, to analyze the attenuation curve behavior of the 50 kVp radiation beam from superficial radiotherapy equipment as Dermopan2 model. The simulations seek to verify the MCNP-5C code performance to study the variation of the attenuation curve - percentage depth dose (PDD) curve - in function of the radiation field dimension used at radiotherapy of skin tumors with 50 kVp X-ray beams. The PDD curve was calculated for six different radiation field sizes with circular geometry of 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 cm in diameter. The radiation source was modeled considering a tungsten target with inclination 30 deg, focal point of 6.5 mm in diameter and energy beam of 50 kVp; the X-ray spectrum was calculated with the MCNP-5C code adopting total filtration (beryllium window of 1 mm and aluminum additional filter of 1 mm). The PDD showed decreasing behavior with the attenuation depth similar what is presented on the literature. There was not significant variation at the PDD values for the radiation field between 1.0 and 4.0 cm in diameter. The differences increased for fields of 5.0 and 6.0 cm and at attenuation depth higher than 1.0 cm. When it is compared the PDD values for fields of 3.0 and 6.0 cm in diameter, it verifies the greater difference (12.6 %) at depth of 5.7 cm, proving the scattered radiation effect. The MCNP-5C code showed as an appropriate procedure to analyze the attenuation curves of the superficial radiotherapy beams. (author)

  3. Brusque belt: a monocyclic evolution ?

    International Nuclear Information System (INIS)

    Basei, M.A.S.

    1990-01-01

    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)

  4. A Prospective Comparison of the Effects of Interfractional Variations on Proton Therapy and Intensity Modulated Radiation Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Moteabbed, Maryam, E-mail: mmoteabbed@partners.org; Trofimov, Alexei; Sharp, Gregory C.; Wang, Yi; Zietman, Anthony L.; Efstathiou, Jason A.; Lu, Hsiao-Ming

    2016-05-01

    Purpose: To quantify and compare the impact of interfractional setup and anatomic variations on proton therapy (PT) and intensity modulated radiation therapy (IMRT) for prostate cancer. Methods and Materials: Twenty patients with low-risk or intermediate-risk prostate cancer randomized to receive passive-scattering PT (n=10) and IMRT (n=10) were selected. For both modalities, clinical treatment plans included 50.4 Gy(RBE) to prostate and proximal seminal vesicles, and prostate-only boost to 79.2 Gy(RBE) in 1.8 Gy(RBE) per fraction. Implanted fiducials were used for prostate localization and endorectal balloons were used for immobilization. Patients in PT and IMRT arms received weekly computed tomography (CT) and cone beam CT (CBCT) scans, respectively. The planned dose was recalculated on each weekly image, scaled, and mapped onto the planning CT using deformable registration. The resulting accumulated dose distribution over the entire treatment course was compared with the planned dose using dose-volume histogram (DVH) and γ analysis. Results: The target conformity index remained acceptable after accumulation. The largest decrease in the average prostate D{sub 98} was 2.2 and 0.7 Gy for PT and IMRT, respectively. On average, the mean dose to bladder increased by 3.26 ± 7.51 Gy and 1.97 ± 6.84 Gy for PT and IMRT, respectively. These values were 0.74 ± 2.37 and 0.56 ± 1.90 for rectum. Differences between changes in DVH indices were not statistically significant between modalities. All volume indices remained within the protocol tolerances after accumulation. The average pass rate for the γ analysis, assuming tolerances of 3 mm and 3%, for clinical target volume, bladder, rectum, and whole patient for PT/IMRT were 100/100, 92.6/99, 99.2/100, and 97.2/99.4, respectively. Conclusion: The differences in target coverage and organs at risk dose deviations for PT and IMRT were not statistically significant under the guidelines of this protocol.

  5. Using haptic feedback to increase seat belt use : traffic tech.

    Science.gov (United States)

    2011-07-01

    The legacy of research on increasing seat belt use has : focused on enactment of seat belt legislation, public education, : high-visibility police enforcement, and seat belt : reminder systems. Several behavioral programs have : produced large, susta...

  6. Origin of the asteroid belt

    International Nuclear Information System (INIS)

    Wetherill, G.W.

    1989-01-01

    Earlier work and concepts relevant to the origin of the asteroid belt are reviewed and considered in the context of the more general question of solar system origin. Several aspects of asteroidal origin by accumulation of smaller bodies have been addressed by new dynamic studies. Numerical and analytical solutions of the dynamical theory of planetesimal accumulation are characterized by a bifurcation into runaway and nonrunaway solutions. The differences in time scales resulting from runaway and nonrunaway growth can be more important than conventional time scale differences determined by heliocentric distances. This introduces new possibilities, e.g., planetary accumulation may be more rapid at the distance of Jupiter than in the asteroid belt, thus permitting Jupiter to control asteroidal growth. Although alternatives must be seriously considered, the most promising approach to asteroidal origin is one in which the initial surface density of the solar nebula varied smoothly between the terrestrial and giant-planet region. In the absence of external perturbations, it is found that runaway growth of excessively large asteroids would then occur on <1 Myr, but fairly modest external perturbations by Jupiter, Saturn or other perturbers, resulting in eccentricities ∼0.01 may quench runaways, truncate asteroidal growth at their present size, and then initiate the necessary loss of asteroidal material by mutual fragmentation

  7. Radiations

    International Nuclear Information System (INIS)

    Pujol Mora, J.

    1999-01-01

    The exposition to ionizing radiations is a constant fact in the life of the human being and its utilization as diagnostic and therapeutic method is generalized. However, it is notorious how as years go on, the fear to the ionizing radiation seems to persist too, and this fact is not limited to the common individual, but to the technical personnel and professional personnel that labors with them same. (S. Grainger) [es

  8. Radiation

    International Nuclear Information System (INIS)

    Davidson, J.H.

    1986-01-01

    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.)

  9. Radiation doses at high altitudes and during space flights

    International Nuclear Information System (INIS)

    Spurny, F.

    2001-01-01

    There are three main sources of radiation exposure during space flights and at high altitudes--galactic cosmic radiation, solar cosmic radiation and radiation of the earth's radiation belt. Their basic characteristics are presented in the first part of this paper.Man's exposure during space flights is discussed in the second part of the paper. Particular attention is devoted to the quantitative and qualitative characteristics of the radiation exposure on near-earth orbits: both theoretical estimation as well as experimental data are presented. Some remarks on radiation protection rules on-board space vehicles are also given.The problems connected with the radiation protection of air crew and passengers of subsonic and supersonic air transport are discussed in the last part of the paper. General characteristics of on-board radiation fields and their variations with flight altitude, geomagnetic parameters of a flight and the solar activity are presented, both based on theoretical estimates and experimental studies. The questions concerning air crew and passenger radiation protection arising after the publication of ICRP 60 recommendation are also discussed. Activities of different institutions relevant to the topic are mentioned; strategies to manage and check this type of radiation exposure are presented and discussed. Examples of results based on the author's personal experience are given, analyzed and discussed. (author)

  10. Seat belt injuries and sigmoid colon trauma.

    OpenAIRE

    Eltahir, E M; Hamilton, D

    1997-01-01

    Colonic seat belt injuries are rare but carry higher mortality rates than small bowel injuries. The case of a 44 year old man is described who had severe sigmoid colon compression injury from his seat belt a few days after a road traffic accident.

  11. Intelligent Belt Conveyor Monitoring and Control

    NARCIS (Netherlands)

    Pang, Y.

    2010-01-01

    Belt conveyors have been used worldwide in continuous material transport for about 250 years. Traditional inspection and monitoring of large-scale belt conveyors focus on individual critical components and response to catastrophic system failures. To prevent operational problems caused by the lack

  12. 36 CFR 1004.15 - Safety belts.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Safety belts. 1004.15 Section 1004.15 Parks, Forests, and Public Property PRESIDIO TRUST VEHICLES AND TRAFFIC SAFETY § 1004.15 Safety... administered by the Presidio Trust will have the safety belt or child restraint system properly fastened at all...

  13. Radiation

    International Nuclear Information System (INIS)

    Winther, J.F.; Ulbak, K.; Dreyer, L.; Pukkala, E.; Oesterlind, A.

    1997-01-01

    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

  14. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation

    Science.gov (United States)

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice ( Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m-2 day-1) and elevated UV-B radiation (E, a 20 % higher dose of UV-B than the reference, 14.4 kJ m-2 day-1), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha-1), Si1 (sodium silicate, 100 kg SiO2 ha-1), Si2 (sodium silicate, 200 kg SiO2 ha-1), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha-1). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate ( Pn), intercellular carbon dioxide (CO2) concentration ( Ci), transpiration rate ( Tr), stomatal conductivity ( Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3 %, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9 %, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2 %, respectively, but decreased Tr by 1.9-10.8 %, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  15. Effects of silicon application on diurnal variations of physiological properties of rice leaves of plants at the heading stage under elevated UV-B radiation.

    Science.gov (United States)

    Lou, Yun-sheng; Wu, Lei; Lixuan, Ren; Meng, Yan; Shidi, Zhao; Huaiwei, Zhu; Yiwei, Zhang

    2016-02-01

    We investigated the effects of silicon (Si) application on diurnal variations of photosynthetic and transpiration physiological parameters in potted rice (Oryza sativa L. cv Nanjing 45) at the heading stage. The plants were subjected to two UV-B radiation levels, i.e., reference UV-B (A, ambient, 12.0 kJ m(-2) day(-1)) and elevated UV-B radiation (E, a 20% higher dose of UV-B than the reference, 14.4 kJ m(-2) day(-1)), and four Si application levels, i.e., Si0 (no silicon supplementation, 0 kg SiO2 ha(-1)), Si1 (sodium silicate, 100 kg SiO2 ha(-1)), Si2 (sodium silicate, 200 kg SiO2 ha(-1)), and Si3 (slag silicon fertilizer, 200 kg SiO2 ha(-1)). Compared with the reference, elevated UV-B radiation decreased the diurnal mean values of the net photosynthetic rate (Pn), intercellular carbon dioxide (CO2) concentration (Ci), transpiration rate (Tr), stomatal conductivity (Gs), and water use efficiency (WUE) by 11.3, 5.5, 10.4, 20.3, and 6.3%, respectively, in plants not supplemented with silicon (Si0), and decreased the above parameters by 3.8-5.5, 0.7-4.8, 4.0-8.7, 7.4-20.2, and 0.7-5.9%, respectively, in plants treated with silicon (Si1, Si2, and Si3), indicating that silicon application mitigates the negative effects of elevated UV-B radiation. Under elevated UV-B radiation, silicon application (Si1, Si2, and Si3) increased the diurnal mean values of Pn, Ci, Gs, and WUE by 16.9-28.0, 3.5-14.3, 16.8-38.7, and 29.0-51.2%, respectively, but decreased Tr by 1.9-10.8%, compared with plants not treated with silicon (E+Si0), indicating that silicon application mitigates the negative effects of elevated UV-B radiation by significantly increasing the P n, C i, G s, and WUE and decreasing the T r of rice. Evident differences existed in mitigating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among different silicon application treatments, exhibiting as Si3>Si2>Si1>Si0. In addition to recycling steel industrial wastes, the

  16. Feed chute geometry for minimum belt wear

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, A W; Wiche, S J [University of Newcastle, Newcastle, NSW (Australia). Centre for Bulk Solids and Particulate Technologies

    1998-09-01

    The paper is concerned with the feeding and transfer of bulk solids in conveyor belt operation. The paper focuses on chute design where the objective is to prevent spillage and minimise both chute and belt wear. It is shown that these objectives may be met through correct dynamic design of the chute and by directing the flow of bulk solids onto the belt at an acceptable incidence angle. The aim is to match the tangential velocity component of the feed velocity as close as possible to the belt velocity. At the same time, it is necessary to limit the impact pressure due to the change in momentum of the bulk solid as it feeds onto the belt. 2 refs., 8 figs.

  17. Method of modifying conveyor belt profile for monitoring ask content of coarse grain coal by radiometric methods

    International Nuclear Information System (INIS)

    Taborsky, J.; Tryzna, P.; Formanek, Z.; Vales, J.

    1982-01-01

    The conveyor belt is gripped in the chosen place with benches to form a V shape with a constant cross section independent of the immediate amount of transported coal. At this point the source and the radiation intensity monitor are placed in horizontal plane on the sides of the conveyor belt. Their connecting line is perpendicular to the direction of the movement of the conveyor belt. Thus, monitoring of the ash content of mined coal and operative control of mining according to measured values are made possible. (Ha)

  18. Variation of the optical energy gap with {gamma}-radiation and thickness in Bi-thin films

    Energy Technology Data Exchange (ETDEWEB)

    Al-Houty, L.; Kassem, M.E.; Abdel Kader, H.I. [Qatar Univ., Doha (Qatar). Dept. of Physics

    1995-02-01

    The effect of {gamma}-radiation and thickness on the optical energy gap of Bi-thin films has been investigated by measuring their optical absorbance. The measurements were carried out on thermally evaporated films having thicknesses in the range 5-20 nm. Different {gamma}-radiation doses were used ranging from 0-300 Mrad. The optical energy gap as well as the absorption coefficient were found to be {gamma}-dose dependent. (author).

  19. Variation of the optical energy gap with γ-radiation and thickness in Bi-thin films

    International Nuclear Information System (INIS)

    Al-Houty, L.; Kassem, M.E.; Abdel Kader, H.I.

    1995-01-01

    The effect of γ-radiation and thickness on the optical energy gap of Bi-thin films has been investigated by measuring their optical absorbance. The measurements were carried out on thermally evaporated films having thicknesses in the range 5-20 nm. Different γ-radiation doses were used ranging from 0-300 Mrad. The optical energy gap as well as the absorption coefficient were found to be γ-dose dependent. (author)

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

    International Nuclear Information System (INIS)

    Djokorayono, Rony; Junus; Rivai, A; Gunarwan; Indarzah

    2003-01-01

    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

  1. Effect of Thermospheric Neutral Density upon Inner Trapped-belt Proton Flux

    Science.gov (United States)

    Wilson, Thomas L.; Lodhi, M. A. K.; Diaz, Abel B.

    2007-01-01

    We wish to point out that a secular change in the Earth's atmospheric neutral density alters charged-particle lifetime in the inner trapped radiation belts, in addition to the changes recently reported as produced by greenhouse gases. Heretofore, changes in neutral density have been of interest primarily because of their effect on the orbital drag of satellites. We extend this to include the orbital lifetime of charged particles in the lower radiation belts. It is known that the charged-belt population is coupled to the neutral density of the atmosphere through changes induced by solar activity, an effect produced by multiple scattering off neutral and ionized atoms along with ionization loss in the thermosphere where charged and neutral populations interact. It will be shown here that trapped-belt flux J is bivariant in energy E and thermospheric neutral density , as J(E,rho). One can conclude that proton lifetimes in these belts are also directly affected by secular changes in the neutral species populating the Earth s thermosphere. This result is a consequence of an intrinsic property of charged-particle flux, that flux is not merely a function of E but is dependent upon density rho when a background of neutrals is present.

  2. A note on the relevance of human population genetic variation and molecular epidemiology to assessing radiation health risk for space travellers

    International Nuclear Information System (INIS)

    Brackley, M.E.; Curry, J.; Glickman, B.W.

    1999-01-01

    We discuss the relevance to space medicine of studies concerning human genetic variation and consequent variable disease susceptibility or sensitivity between individuals. The size of astronaut and cosmonaut populations is both presently and cumulatively small, and despite the launch of the International Space Station, unlikely to increase by orders of magnitude within the foreseeable future. In addition, astronauts-cosmonauts constitute unrepresentative samples of their national populations. While the context of exposure for the astronaut-cosmonaut group is one unlikely to be replicated elsewhere than in space, aspects of specific exposures may be simulated by events such as occupational radiation exposure or radiation therapy. Hence, population-based studies of genetic susceptibility or sensitivity to disease, especially where it is precipitated by events that may simulate consequences of the space environment, likely will prove of value in assessing long-term health risks

  3. Observed use of automatic seat belts in 1987 cars.

    Science.gov (United States)

    Williams, A F; Wells, J K; Lund, A K; Teed, N

    1989-10-01

    Usage of the automatic belt systems supplied by six large-volume automobile manufacturers to meet the federal requirements for automatic restraints were observed in suburban Washington, D.C., Chicago, Los Angeles, and Philadelphia. The different belt systems studied were: Ford and Toyota (motorized, nondetachable automatic shoulder belt), Nissan (motorized, detachable shoulder belt), VW and Chrysler (nonmotorized, detachable shoulder belt), and GM (nonmotorized detachable lap and shoulder belt). Use of automatic belts was significantly greater than manual belt use in otherwise comparable late-model cars for all manufacturers except Chrysler; in Chrysler cars, automatic belt use was significantly lower than manual belt use. The automatic shoulder belts provided by Ford, Nissan, Toyota, and VW increased use rates to about 90%. Because use rates were lower in Ford cars with manual belts, their increase was greater. GM cars had the smallest increase in use rates; however, lap belt use was highest in GM cars. The other manufacturers supply knee bolsters to supplement shoulder belt protection; all--except VW--also provide manual lap belts, which were used by about half of those who used the automatic shoulder belt. The results indicate that some manufacturers have been more successful than others in providing automatic belt systems that result in high use that, in turn, will mean fewer deaths and injuries in those cars.

  4. Computer-Aided design of belt and pulley systems using Visual Basic

    African Journals Online (AJOL)

    A Visual Basic Code “DriveCad” was developed for analysis and design of flat and V-belt drives. The Code was used to solve design problems and the results compared favorably with data generated by manual computat-ions, with variation of less than 1.6 %. DriveCad was used to generate scaled 2-dimensional drawings ...

  5. Minimizing dose variation from the interplay effect in stereotactic radiation therapy using volumetric modulated arc therapy for lung cancer.

    Science.gov (United States)

    Kubo, Kazuki; Monzen, Hajime; Tamura, Mikoto; Hirata, Makoto; Ishii, Kentaro; Okada, Wataru; Nakahara, Ryuta; Kishimoto, Shun; Kawamorita, Ryu; Nishimura, Yasumasa

    2018-03-01

    It is important to improve the magnitude of dose variation that is caused by the interplay effect. The aim of this study was to investigate the impact of the number of breaths (NBs) to the dose variation for VMAT-SBRT to lung cancer. Data on respiratory motion and multileaf collimator (MLC) sequence were collected from the cases of 30 patients who underwent radiotherapy with VMAT-SBRT for lung cancer. The NBs in the total irradiation time with VMAT and the maximum craniocaudal amplitude of the target were calculated. The MLC sequence complexity was evaluated using the modulation complexity score for VMAT (MCSv). Static and dynamic measurements were performed using a cylindrical respiratory motion phantom and a micro ionization chamber. The 1 standard deviation which were obtained from 10 dynamic measurements for each patient were defined as dose variation caused by the interplay effect. The dose distributions were also verified with radiochromic film to detect undesired hot and cold dose spot. Dose measurements were also performed with different NBs in the same plan for 16 patients in 30 patients. The correlations between dose variations and parameters assessed for each treatment plan including NBs, MCSv, the MCSv/amplitude quotient (TMMCSv), and the MCSv/amplitude quotient × NBs product (IVS) were evaluated. Dose variation was decreased with increasing NBs, and NBs of >40 times maintained the dose variation within 3% in 15 cases. The correlation between dose variation and IVS which were considered NBs was shown stronger (R 2  = 0.43, P 40 times during irradiation of two partial arcs VMAT (i.e., NBs = 16 breaths per minute) may be suitable for VMAT-SBRT for lung cancer. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  6. SNP in TXNRD2 Associated With Radiation-Induced Fibrosis: A Study of Genetic Variation in Reactive Oxygen Species Metabolism and Signaling

    International Nuclear Information System (INIS)

    Edvardsen, Hege; Landmark-Høyvik, Hege; Reinertsen, Kristin V.; Zhao, Xi; Grenaker-Alnæs, Grethe Irene; Nebdal, Daniel; Syvänen, Ann-Christine; Rødningen, Olaug; Alsner, Jan; Overgaard, Jens; Borresen-Dale, Anne-Lise; Fosså, Sophie D.; Kristensen, Vessela N.

    2013-01-01

    Purpose: The aim of the study was to identify noninvasive markers of treatment-induced side effects. Reactive oxygen species (ROS) are generated after irradiation, and genetic variation in genes related to ROS metabolism might influence the level of radiation-induced adverse effects (AEs). Methods and Materials: 92 breast cancer (BC) survivors previously treated with hypofractionated radiation therapy were assessed for the AEs subcutaneous atrophy and fibrosis, costal fractures, lung fibrosis, pleural thickening, and telangiectasias (median follow-up time 17.1 years). Single-nucleotide polymorphisms (SNPs) in 203 genes were analyzed for association to AE grade. SNPs associated with subcutaneous fibrosis were validated in an independent BC survivor material (n=283). The influence of the studied genetic variation on messenger ribonucleic acid (mRNA) expression level of 18 genes previously associated with fibrosis was assessed in fibroblast cell lines from BC patients. Results: Subcutaneous fibrosis and atrophy had the highest correlation (r=0.76) of all assessed AEs. The nonsynonymous SNP rs1139793 in TXNRD2 was associated with grade of subcutaneous fibrosis, the reference T-allele being more prevalent in the group experiencing severe levels of fibrosis. This was confirmed in another sample cohort of 283 BC survivors, and rs1139793 was found significantly associated with mRNA expression level of TXNRD2 in blood. Genetic variation in 24 ROS-related genes, including EGFR, CENPE, APEX1, and GSTP1, was associated with mRNA expression of 14 genes previously linked to fibrosis (P≤.005). Conclusion: Development of subcutaneous fibrosis can be associated with genetic variation in the mitochondrial enzyme TXNRD2, critically involved in removal of ROS, and maintenance of the intracellular redox balance

  7. Drive Alive: Teen Seat Belt Survey Program

    Directory of Open Access Journals (Sweden)

    Loftin, Laurel

    2010-08-01

    Full Text Available Objective: To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP, a theory-driven intervention built on highway safety best practices.Methods: The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was the use of incentives, such as gift cards, to promote teen seat belt use. The third component involved disincentives, such as increased police patrol and school policies. The fourth component was a programmatic intervention that focused on education and media coverage of the DAPP program.Results: Eleven pre-intervention surveys and nine post-intervention surveys were conducted before and after the intervention. The pre- and post-intervention seat belt usage showed significant differences (p<0.0001. The average pre-intervention seat belt usage rate was 51.2%, while the average post-intervention rate was 74.5%. This represents a percentage point increase of 23.3 in seat belt use after the DAPP intervention.Conclusion: Based on seat belt observational surveys, the DAPP was effective in increasing seat belt use among rural high school teenagers. Utilizing a theory-based program that builds on existing best practices can increase the observed seat belt usage among rural high school students. [West J Emerg Med. 2010; 11(3: 280-283.

  8. Belt design central to conveyor performance

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-15

    While a conveyor system comprises a complex range of components, it is the belt design which ultimately dictates its core performance and reliability. The complexity of modern systems can be seen by the recent contract awarded to ThyssenKrupp Foerdertechnik (TKF) to supply systems for a new steel plant (including a coking plant and a power plant) to be built in Sepetiba Bay in Brazil. Phoenix has designed the Phoenotec system to protect steel cord conveyor belts. Fenner Dunlop has developed Fenaplast belting with nylon or polyester load-bearing warp and weft yarns for good impact resistance. 2 photos.

  9. Long-term variations of the UV-B radiation over Central Europe as derived from the reconstructed UV time series

    Directory of Open Access Journals (Sweden)

    J. W. Krzyscin

    2004-04-01

    Full Text Available The daily doses of the erythemally weighted UV radiation are reconstructed for three sites in Central Europe: Belsk-Poland (1966–2001, Hradec Kralove-Czech Republic (1964–2001, and Tõravere-Estonia (1967–2001 to discuss the UV climatology and the long-term changes of the UV-B radiation since the mid 1960s. Various reconstruction models are examined: a purely statistical model based on the Multivariate Adaptive Regression Splines (MARS methodology, and a hybrid model combining radiative transfer model calculations with empirical estimates of the cloud effects on the UV radiation. Modeled long-term variations of the surface UV doses appear to be in a reasonable agreement with the observed ones. A simple quality control procedure is proposed to check the homogeneity of the biometer and pyranometer data. The models are verified using the results of UV observations carried out at Belsk since 1976. MARS provides the best estimates of the UV doses, giving a mean difference between the modeled and observed monthly means equal to 0.6±2.5%. The basic findings are: similar climatological forcing by clouds for all considered stations (~30% reduction in the surface UV, long-term variations in UV monthly doses having the same temporal pattern for all stations with extreme low monthly values (~5% below overall mean level at the end of the 1970s and extreme high monthly values (~5% above overall mean level in the mid 1990s, regional peculiarities in the cloud long-term forcing sometimes leading to extended periods with elevated UV doses, recent stabilization of the ozone induced UV long-term changes being a response to a trendless tendency of total ozone since the mid 1990s. In the case of the slowdown of the total ozone trend over Northern Hemisphere mid-latitudes it seems that clouds will appear as the most important modulator of the UV radiation both in long- and short-time scales over next decades. Key words. Atmospheric composition and structure

  10. Long-term variations of the UV-B radiation over Central Europe as derived from the reconstructed UV time series

    Directory of Open Access Journals (Sweden)

    J. W. Krzyscin

    2004-04-01

    Full Text Available The daily doses of the erythemally weighted UV radiation are reconstructed for three sites in Central Europe: Belsk-Poland (1966–2001, Hradec Kralove-Czech Republic (1964–2001, and Tõravere-Estonia (1967–2001 to discuss the UV climatology and the long-term changes of the UV-B radiation since the mid 1960s. Various reconstruction models are examined: a purely statistical model based on the Multivariate Adaptive Regression Splines (MARS methodology, and a hybrid model combining radiative transfer model calculations with empirical estimates of the cloud effects on the UV radiation. Modeled long-term variations of the surface UV doses appear to be in a reasonable agreement with the observed ones. A simple quality control procedure is proposed to check the homogeneity of the biometer and pyranometer data. The models are verified using the results of UV observations carried out at Belsk since 1976. MARS provides the best estimates of the UV doses, giving a mean difference between the modeled and observed monthly means equal to 0.6±2.5%. The basic findings are: similar climatological forcing by clouds for all considered stations (~30% reduction in the surface UV, long-term variations in UV monthly doses having the same temporal pattern for all stations with extreme low monthly values (~5% below overall mean level at the end of the 1970s and extreme high monthly values (~5% above overall mean level in the mid 1990s, regional peculiarities in the cloud long-term forcing sometimes leading to extended periods with elevated UV doses, recent stabilization of the ozone induced UV long-term changes being a response to a trendless tendency of total ozone since the mid 1990s. In the case of the slowdown of the total ozone trend over Northern Hemisphere mid-latitudes it seems that clouds will appear as the most important modulator of the UV radiation both in long- and short-time scales over next decades.

    Key words. Atmospheric composition and

  11. Variations in the radiation sensitivity of foodborne pathogens associated with complex ready-to-eat food products

    International Nuclear Information System (INIS)

    Sommers, Christopher H.; Boyd, Glenn

    2006-01-01

    Foodborne illness outbreaks and product recalls are occasionally associated with ready-to-eat (RTE) sandwiches and other 'heat and eat' multi-component RTE products. Ionizing radiation can inactivate foodborne pathogens on meat and poultry, fruits and vegetables, seafood, and RTE meat products. However, less data are available on the ability of low-dose ionizing radiation, doses under 5 kGy typically used for pasteurization purposes, to inactivate pathogenic bacteria on complex multi-component food products. In this study, the efficacy of ionizing radiation to inactivate Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Yersinia enterocolitica on RTE foods including a 'frankfurter on a roll', a 'beef cheeseburger on a bun' and a 'vegetarian cheeseburger on a bun' was investigated. The average D-10 values, the radiation dose needed to inactivate 1 log 1 of pathogen, by bacterium species, were 0.61, 0.54, 0.47, 0.36 and 0.15 kGy for Salmonella spp., S. aureus, L. monocytogenes, E. coli O157:H7, and Y. enterocolitica, respectively when inoculated onto the three product types. These results indicate that irradiation may be an effective means for inactivating common foodborne pathogens including Salmonella spp, S. aureus, L. monocytogenes, E. coli O157:H7 and Y. enterocolitica in complex RTE food products such as 'heat and eat' sandwich products

  12. Variations in the radiation sensitivity of foodborne pathogens associated with complex ready-to-eat food products

    Science.gov (United States)

    Sommers, Christopher H.; Boyd, Glenn

    2006-07-01

    Foodborne illness outbreaks and product recalls are occasionally associated with ready-to-eat (RTE) sandwiches and other "heat and eat" multi-component RTE products. Ionizing radiation can inactivate foodborne pathogens on meat and poultry, fruits and vegetables, seafood, and RTE meat products. However, less data are available on the ability of low-dose ionizing radiation, doses under 5 kGy typically used for pasteurization purposes, to inactivate pathogenic bacteria on complex multi-component food products. In this study, the efficacy of ionizing radiation to inactivate Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Yersinia enterocolitica on RTE foods including a "frankfurter on a roll", a "beef cheeseburger on a bun" and a "vegetarian cheeseburger on a bun" was investigated. The average D-10 values, the radiation dose needed to inactivate 1 log 10 of pathogen, by bacterium species, were 0.61, 0.54, 0.47, 0.36 and 0.15 kGy for Salmonella spp., S. aureus, L. monocytogenes, E. coli O157:H7, and Y. enterocolitica, respectively when inoculated onto the three product types. These results indicate that irradiation may be an effective means for inactivating common foodborne pathogens including Salmonella spp, S. aureus, L. monocytogenes, E. coli O157:H7 and Y. enterocolitica in complex RTE food products such as 'heat and eat" sandwich products.

  13. VARIATIONS IN RADIATION SENSITIVITY AND REPAIR AMONG DIFFERENT HEMATOPOIETIC STEM-CELL SUBSETS FOLLOWING FRACTIONATED-IRRADIATION

    NARCIS (Netherlands)

    DOWN, JD; BOUDEWIJN, A; VANOS, R; THAMES, HD; PLOEMACHER, RE

    1995-01-01

    The radiation dose-survival of various hematopoietic cell subsets in murine bone marrow (BM) was determined in the cobblestone area forming cell (CAFC) assay under conditions of single-, split-, and multiple-dose irradiation. A greater recovery in cell survival with decreasing dose per fraction, or

  14. 30 CFR 57.4503 - Conveyor belt slippage.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor belt slippage. 57.4503 Section 57.4503... Control Installation/construction/maintenance § 57.4503 Conveyor belt slippage. (a) Surface belt conveyors...) Underground belt conveyors shall be equipped with a detection system capable of automatically stopping the...

  15. 30 CFR 56.4503 - Conveyor belt slippage.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor belt slippage. 56.4503 Section 56.4503... Control Installation/construction/maintenance § 56.4503 Conveyor belt slippage. Belt conveyors within... shall attend the belt at the drive pulley when it is necessary to operate the conveyor while temporarily...

  16. 30 CFR 75.1403-5 - Criteria-Belt conveyors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Criteria-Belt conveyors. 75.1403-5 Section 75... Criteria—Belt conveyors. (a) Positive-acting stop controls should be installed along all belt conveyors... can be stopped or started at any location. (b) Belt conveyors used for regularly scheduled mantrips...

  17. Compliance with Seat Belt Use in Makurdi, Nigeria: An ...

    African Journals Online (AJOL)

    Background: Seat belts are designed to reduce injuries due to road crash among vehicle occupants. Aims: This study aims to determine the availability of seat belt in vehicles and compliance with seat belt use among vehicle occupants. Materials and methods: This was a 24‑h direct observational study of seat belt usage ...

  18. Measurement of Gamma-ray Energy Spectrum According to Temperature Variation Using a Fiber-Optic Radiation Sensor Based on YSO:Ce Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, H.; Yoo, W. J.; Shin, S. H.; Jang, J. S.; Kim, J. S.; Kwon, G.; Lee, D. E.; Jang, K. W.; Lee, B. [BK21 Plus Research Institute of Biomedical Engineering, Konkuk University, Chungju (Korea, Republic of)

    2015-05-15

    As an alternative to conventional radiation detectors, various fiber-optic radiation sensors (FORSs) have been investigated for gamma-ray monitoring because of their various desirable advantages, such as their small sensing volume, substantial flexibility, remote operation, ability to make real-time measurement, and immunity to high electromagnetic interference. In general, the basic principle of a radiation detection using scintillators is to measure the scintillating light signals generated from the interactions between the scintillators and the radiations. To measure gamma-ray, the inorganic scintillators used in the FORS should have some properties, such as high atomic material, high light yields, fast decay time, high density, and high stopping power. For these reasons, a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) crystal has been introduced as a promising scintillator in various radiation sensor applications. According to the recent studies, however, LYSO:Ce crystal is impossible to be applied in high-temperature conditions because it serves the fluctuations of its light yields with the temperature variation (i.e., thermosluminescence). In this study, to obtain gamma-ray energy spectra by measuring scintillating light signals emitted from the scintillators in high-temperature conditions, we first fabricated an FORS system using various inorganic scintillator crystals and then evaluated the light yields of each inorganic scintillator. As a promising scintillator for use in high-temperature conditions, a cerium-doped yttrium orthosilicate (YSO:Ce) crystal was selected and evaluated its thermal property according to the elevated temperature up to 300 .deg. C. We fabricated an FORS using inorganic scintillator and an optical fiber bundle. To select an adequate scintillator to apply in high-temperature conditions, the gamma-ray energy spectra were obtained by using four kinds of inorganic scintillators. From the experimental results, we selected YSO

  19. 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.

  20. 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...

  1. Dynamics Analysis and Modeling of Rubber Belt in Large Mine Belt Conveyors

    OpenAIRE

    Gao Yang

    2014-01-01

    Rubber belt not only is one of the key components of belt conveyor, but also affects the overall performance of the core part. Research on dynamics analysis of large conveyor not only helps to improve the reliability and design level, but also can guide the rational selection of conveyor safety factor, and effectively reduce the cost of the conveyor belt. Based on unique viscoelastic properties of belt conveyor, it was simplified as one-dimensional viscoelastic rod in this study, and then a d...

  2. The Stability of the Conveyor Belt Pontoon

    Directory of Open Access Journals (Sweden)

    Jiří PODEŠVA

    2011-06-01

    Full Text Available To lead the conveyor belt transport cross water area the pontoon are used to support the carrying structure of the belts. The accident can happen when the pontoon turnover. For this reason the pontoon stability is investigated. The stability is described by the Reed’s diagram. This can be constructed analytically or via numerical modeling. Both methods are described in the paper.

  3. Belt Conveyor Dynamic Characteristics and Influential Factors

    OpenAIRE

    Li, Junxia; Pang, Xiaoxu

    2018-01-01

    This paper uses the Kelvin-Voigt viscoelastic model to establish the continuous dynamic equations for tail hammer tension belt conveyors. The viscoelastic continuity equations are solved using the generalized coordinate method. We analyze various factors influencing longitudinal vibration of the belt conveyor by simulation and propose a control strategy to limit the vibration. The proposed approach and control strategy were verified by several experimental researches and cases. The proposed a...

  4. Seat-belt message and the law?

    Science.gov (United States)

    Sengupta, S K; Patil, N G; Law, G

    1989-09-01

    This paper attempts to draw together available information on the use of seat belts, one of the most important safety devices for a person in a car. Considering the high rate of mortality and morbidity due to road traffic accidents in Papua New Guinea the authors strongly feel that seat-belt usage should be made compulsory. When one looks at the history of the implementation of such a successful countermeasure in other countries it seems that legislation is the only answer.

  5. Variations in the radiation sensitivity of foodborne pathogens associated with complex ready-to-eat food products

    Energy Technology Data Exchange (ETDEWEB)

    Sommers, Christopher H. [Food Safety Intervention Technologies Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038 (United States)]. E-mail: csommers@errc.ars.usda.gov; Boyd, Glenn [Food Safety Intervention Technologies Research Unit, Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038 (United States)

    2006-07-15

    Foodborne illness outbreaks and product recalls are occasionally associated with ready-to-eat (RTE) sandwiches and other 'heat and eat' multi-component RTE products. Ionizing radiation can inactivate foodborne pathogens on meat and poultry, fruits and vegetables, seafood, and RTE meat products. However, less data are available on the ability of low-dose ionizing radiation, doses under 5 kGy typically used for pasteurization purposes, to inactivate pathogenic bacteria on complex multi-component food products. In this study, the efficacy of ionizing radiation to inactivate Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Yersinia enterocolitica on RTE foods including a 'frankfurter on a roll', a 'beef cheeseburger on a bun' and a 'vegetarian cheeseburger on a bun' was investigated. The average D-10 values, the radiation dose needed to inactivate 1 log{sub 1} of pathogen, by bacterium species, were 0.61, 0.54, 0.47, 0.36 and 0.15 kGy for Salmonella spp., S. aureus, L. monocytogenes, E. coli O157:H7, and Y. enterocolitica, respectively when inoculated onto the three product types. These results indicate that irradiation may be an effective means for inactivating common foodborne pathogens including Salmonella spp, S. aureus, L. monocytogenes, E. coli O157:H7 and Y. enterocolitica in complex RTE food products such as 'heat and eat' sandwich products.

  6. Daily, seasonal, and latitudinal variations in solar ultraviolet A and B radiation in relation to vitamin D production and risk for skin cancer.

    Science.gov (United States)

    Grigalavicius, Mantas; Moan, Johan; Dahlback, Arne; Juzeniene, Asta

    2016-01-01

    Solar ultraviolet (UV) radiation varies with latitude, time of day, and season. Both spectral UV composition and ambient UV dose lead to different health outcomes at different latitudes. Finding the optimal time for sun exposure, whereby the positive effects of UV exposure (vitamin D) are facilitated and the negative effects (skin cancer, photoimmunosuppression) avoided are the most important consideration in modern skin cancer prevention programs. This paper focuses on the latitude dependency of UVB, UVA, vitamin D production, and skin cancer risk in Caucasians. Biologically effective UVB (280-315 nm) and UVA (315-400 nm) doses were calculated using radiative transfer models with appropriate climatologic data for selected locations. Incidences of squamous cell carcinoma (SCC) and cutaneous melanoma (CM) were retrieved from cancer registries and published articles. Annual doses of UVA radiation decrease much less with increasing latitude than annual doses of UVB. Incidences of CM also decrease less steeply with increasing latitude than incidences of SCC. As SCC is caused mainly by UVB, these observations support the assumption that UVA plays an important role in the development of CM. The variations in UVA (relevant to CM) and UVB (relevant to vitamin D production) over 1 day differ: the UVB : UVA ratio is maximal at noon. The best way to obtain a given dose of vitamin D with minimal carcinogenic risk is through a non-burning exposure in the middle of the day, rather than in the afternoon or morning. © 2015 The International Society of Dermatology.

  7. Effects of conditioning with variations of temperatures on the susceptibility of the medfly, Ceratitis capitata (Wied.) to gamma radiation

    International Nuclear Information System (INIS)

    Hussin, E.K.; Abdel-Megeed, M.I.; Wakid, A.M.; Fadel, A.M.

    2010-01-01

    An attempt was carried out to investigate the effect of gamma irradiation on sterility and male mating competitiveness of the medfly C. capitata (Wied.) under hypo and hyperthermia in order to minimize the deleterious effects of radiation on insects. Low, moderate and high temperature (5, 25 and 32 degree C) were applied to pupal and adult stages of C. capitata at different ages before and/or after irradiation with the doses (70, 90 and 110 Gy) of gamma radiation. Sterility of pupae or adults exposed to low temperature (5 degree C) before or after irradiation was increased compared with their controls. The rate of increase was more clear in pupae exposed after irradiation and in adults exposed before irradiation. When pupae or adults were treated with high temperature (32 degree C) for 24 h before or after irradiation, adult sterility was increased with increasing the radiation dose. The competitiveness values were greatly higher when pupae or adults were exposed to low temperature (5 degree C) than those exposed to moderate or high temperature before irradiation.

  8. Efficiency of ETV diagrams as diagnostic tools for long-term period variations. II. Non-conservative mass transfer, and gravitational radiation

    Science.gov (United States)

    Nanouris, N.; Kalimeris, A.; Antonopoulou, E.; Rovithis-Livaniou, H.

    2015-03-01

    Context. The credibility of an eclipse timing variation (ETV) diagram analysis is investigated for various manifestations of the mass transfer and gravitational radiation processes in binary systems. The monotonicity of the period variations and the morphology of the respective ETV diagrams are thoroughly explored in both the direct impact and the accretion disk mode of mass transfer, accompanied by different types of mass and angular momentum losses (through a hot-spot emission from the gainer and via the L2/L3 points). Aims: Our primary objective concerns the traceability of each physical mechanism by means of an ETV diagram analysis. Also, possible critical mass ratio values are sought for those transfer modes that involve orbital angular momentum losses strong enough to dictate the secular period changes even when highly competitive mechanisms with the opposite direction act simultaneously. Methods: The dot{J-dot{P}} relation that governs the orbital evolution of a binary system is set to provide the exact solution for the period and the function expected to represent the subsequent eclipse timing variations. The angular momentum transport is parameterized through appropriate empirical relations, which are inferred from semi-analytical ballistic models. Then, we numerically determine the minimum temporal range over which a particular mechanism is rendered measurable, as well as the critical mass ratio values that signify monotonicity inversion in the period modulations. Results: Mass transfer rates comparable to or greater than 10-8 M⊙ yr-1 are measurable for typical noise levels of the ETV diagrams, regardless of whether the process is conservative. However, the presence of a transient disk around the more massive component defines a critical mass ratio (qcr ≈ 0.83) above which the period turns out to decrease when still in the conservative regime, rendering the measurability of the anticipated variations a much more complicated task. The effects of

  9. Contribution of Topography and Incident Solar Radiation to Variation of Soil and Plant Litter at an Area with Heterogeneous Terrain

    OpenAIRE

    Felipe Cito Nettesheim; Tiago de Conto; Marcos Gervasio Pereira; Deivid Lopes Machado

    2015-01-01

    Natural processes that determine soil and plant litter properties are controlled by multiple factors. However, little attention has been given to distinguishing the effects of environmental factors from the effects of spatial structure of the area on the distribution of soil and litter properties in tropical ecosystems covering heterogeneous topographies. The aim of this study was to assess patterns of soil and litter variation in a tropical area that intercepts different levels of solar radi...

  10. Ice Caps and Ice Belts: The Effects of Obliquity on Ice−Albedo Feedback

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Brian E. J. [Department of Atmospheric and Environmental Sciences, University at Albany (State University of New York), 1400 Washington Avenue, Albany, NY 12222 (United States); Cronin, Timothy W. [Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Bitz, Cecilia M., E-mail: brose@albany.edu [Department of Atmospheric Sciences, MS 351640, University of Washington, Seattle, WA 98195-1640 (United States)

    2017-09-01

    Planetary obliquity determines the meridional distribution of the annual mean insolation. For obliquity exceeding 55°, the weakest insolation occurs at the equator. Stable partial snow and ice cover on such a planet would be in the form of a belt about the equator rather than polar caps. An analytical model of planetary climate is used to investigate the stability of ice caps and ice belts over the widest possible range of parameters. The model is a non-dimensional diffusive Energy Balance Model, representing insolation, heat transport, and ice−albedo feedback on a spherical planet. A complete analytical solution for any obliquity is given and validated against numerical solutions of a seasonal model in the “deep-water” regime of weak seasonal ice line migration. Multiple equilibria and unstable transitions between climate states (ice-free, Snowball, or ice cap/belt) are found over wide swaths of parameter space, including a “Large Ice-Belt Instability” and “Small Ice-Belt Instability” at high obliquity. The Snowball catastrophe is avoided at weak radiative forcing in two different scenarios: weak albedo feedback and inefficient heat transport (favoring stable partial ice cover), or efficient transport at high obliquity (favoring ice-free conditions). From speculative assumptions about distributions of planetary parameters, three-fourths to four-fifths of all planets with stable partial ice cover should be in the form of Earth-like polar caps.

  11. Genetical analysis of the induced variation by gamma radiation in quantitative characters of Caupi [Vigna unguiculata (L.) Walp.

    International Nuclear Information System (INIS)

    Araujo, J.P.P. de.

    1987-10-01

    Genetical analysis procedures of the cobalt 60 gamma radiation effects in the induced mutations in quantitative characters of Caupi BR-1 Poty. The following characters were evaluated: day to first flower (FI), number of pods per plant (NVP), pod lenght (CMV), number of suds per pod (NSV), 100 seed wright (PCS), seed yield per plant (PSP) and seed yield per plant estimated by yield components (PSPE). The resistance of irradiated populations to cowpea aphid-borne mosaic virus (CpAMV)was also evaluated. (L.M.J.) [pt

  12. THE ASTEROID BELT AS A RELIC FROM A CHAOTIC EARLY SOLAR SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Izidoro, André; Raymond, Sean N.; Pierens, Arnaud [Laboratoire d’astrophysique de Bordeaux, Université de Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, F-33615 Pessac (France); Morbidelli, Alessandro [University of Nice-Sophia Antipolis, CNRS, Observatoire de la Côte d’Azur, Laboratoire Lagrange, BP 4229, F-06304 Nice Cedex 4 (France); Winter, Othon C. [UNESP, Univ. Estadual Paulista—Grupo de Dinâmica Orbital and Planetologia, Guaratinguetá, CEP 12.516-410, São Paulo (Brazil); Nesvorny' , David, E-mail: izidoro.costa@gmail.com [Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302 (United States)

    2016-12-10

    The orbital structure of the asteroid belt holds a record of the solar system’s dynamical history. The current belt only contains ∼10{sup −3} Earth masses yet the asteroids’ orbits are dynamically excited, with a large spread in eccentricity and inclination. In the context of models of terrestrial planet formation, the belt may have been excited by Jupiter’s orbital migration. The terrestrial planets can also be reproduced without invoking a migrating Jupiter; however, as it requires a severe mass deficit beyond Earth’s orbit, this model systematically under-excites the asteroid belt. Here we show that the orbits of the asteroids may have been excited to their current state if Jupiter’s and Saturn’s early orbits were chaotic. Stochastic variations in the gas giants’ orbits cause resonances to continually jump across the main belt and excite the asteroids’ orbits on a timescale of tens of millions of years. While hydrodynamical simulations show that the gas giants were likely in mean motion resonance at the end of the gaseous disk phase, small perturbations could have driven them into a chaotic but stable state. The gas giants’ current orbits were achieved later, during an instability in the outer solar system. Although it is well known that the present-day solar system exhibits chaotic behavior, our results suggest that the early solar system may also have been chaotic.

  13. An under-belt capacitance and γ-ray backscatter gauge for on-line determination of moisture in coal

    International Nuclear Information System (INIS)

    Cutmore, N.G.; Roczniok, A.F.; Sowerby, B.D.

    1987-01-01

    A non-contacting under-belt capacitance and γ-ray backscatter technique has been developed for on-line measurement of moisture in coal. In this technique, moisture was correlated with radiofrequency susceptance and conductance, determined using an under-belt capacitance sensor in which a fringing electric field interrogates a layer of coal on the conveyor belt directly above the sensor. To compensate for variation in the density and thickness of the coal layer, an under-belt γ-ray backscatter gauge was used to measure an equivalent volume of coal. Laboratory measurements have shown that this technique compensates more accurately for density and thickness than does their direct physical measurement. (author)

  14. Microfluidic magnetic bead conveyor belt.

    Science.gov (United States)

    van Pelt, Stijn; Frijns, Arjan; den Toonder, Jaap

    2017-11-07

    Magnetic beads play an important role in the miniaturization of clinical diagnostics systems. In lab-on-chip platforms, beads can be made to link to a target species and can then be used for the manipulation and detection of this species. Current bead actuation systems utilize complex on-chip coil systems that offer low field strengths and little versatility. We demonstrate a novel system based on an external rotating magnetic field and on-chip soft-magnetic structures to focus the field locally. These structures were designed and optimized using finite element simulations in order to create a number of local flux density maxima. These maxima, to which the magnetic beads are attracted, move over the chip surface in a continuous way together with the rotation of the external field, resulting in a mechanism similar to that of a conveyor belt. A prototype was fabricated using PDMS molding techniques mixed with iron powder for the magnetic structures. In the subsequent experiments, a quadrupole electromagnet was used to create the rotating external field. We observed that beads formed agglomerates that rolled over the chip surface, just above the magnetic structures. Field rotation frequencies between 0.1-50 Hz were tested resulting in magnetic bead speeds of over 1 mm s -1 for the highest frequency. With this, we have shown that our novel concept works, combining a simple design and simple operation with a powerful and versatile method for bead actuation. This makes it a promising method for further research and utilization in lab-on-chip systems.

  15. 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.

  16. Variation in normal and tumor tissue sensitivity of mice to ionizing radiation-induced DNA strand breaks in vivo

    International Nuclear Information System (INIS)

    Meyn, R.E.; Jenkins, W.T.

    1983-01-01

    The efficiency of DNA strand break formation in normal and tumor tissues of mice was measured using the technique of alkaline elution coupled with a microfluorometric determination of DNA. This methodology allowed measurement of the DNA strand breaks produced in tissues irradiated in vivo with doses of radiation comparable to those used in radiotherapy (i.e., 1.0 gray) without the necessity for the cells to be dividing and incorporating radioactive precursors to label the DNA. The results showed that substantial differences existed among various tissues in terms of the amount of DNA strand break damage produced for a given dose of radiation. Of the normal tissues, the most breaks were produced in bone marrow and the least were produced in gut. Furthermore, strand break production was relatively inefficient in the tumor compared to the normal tissues. The efficiency of DNA strand break formation measured in the cells from the tissues irradiated in vitro was much more uniform and considerably greater than that measured in vivo, suggesting that the normal tissues in the animal may be radiobiologically hypoxic

  17. Impacts of interactive dust and its direct radiative forcing on interannual variations of temperature and precipitation in winter over East Asia: Impacts of Dust on IAVs of Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Sijia [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Yang, Yang [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Liu, Ying [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Singh, Balwinder [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Ghan, Steven J. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2017-08-24

    We used 150-year pre-industrial simulations of the Community Earth System Model (CESM) to quantify the impacts of interactively-modeled dust emissions on the interannual variations of temperature and precipitation over East Asia during the East Asian Winter Monsoon (EAWM) season. The simulated December-January-February dust column burden and dust optical depth are lower over northern China in the strongest EAWM years than those of the weakest years, with regional mean values lower by 38.3% and 37.2%, respectively. The decrease in dust over the dust source regions (the Taklamakan and Gobi Deserts) and the downwind region (such as the North China Plain) leads to an increase in direct radiative forcing (RF) both at the surface and top of atmosphere by up to 1.5 and 0.75 W m-2, respectively. The effects of EAWM-related variations in surface winds, precipitation and their effects on dust emissions and wet removal contribute about 67% to the total dust-induced variations of direct RF at the surface and partly offset the cooling that occurs with the EAWM strengthening by heating the surface. The variations of surface air temperature induced by the changes in wind and dust emissions increase by 0.4-0.6 K over eastern coastal China, northeastern China, and Japan, which weakens the impact of EAWM on surface air temperature by 3–18% in these regions. The warming results from the combined effects of changes in direct RF and easterly wind anomalies that bring warm air from the ocean to these regions. Moreover, the feedback of the changes in wind on dust emissions weakens the variations of the sea level pressure gradient on the Siberian High while enhancing the Maritime Continent Low. Therefore, cold air is prevented from being transported from Siberia, Kazakhstan, western and central China to the western Pacific Ocean and decreases surface air temperature by 0.6 K and 2 K over central China and the Tibetan Plateau, respectively. Over eastern coastal China, the variations of

  18. In vivo variation of micronuclei in BALB/c mice after low and high doses of gamma radiation

    International Nuclear Information System (INIS)

    Strain, D.; Allen, B.J.

    1996-01-01

    Full text: An adaptive response to ionising radiation exists if a low level or priming dose reduces the effect of a subsequent high or challenge dose. This has been demonstrated in vitro using the frequency of micronuclei formation as a measure of radiation-induced DNA damage. The objective of this project was to use the same approach with an animal model to investigate the existence of an in vivo adaptive response. The experimental design involved priming doses of 0.005 or 0.01 Gy and a challenge dose of 4 Gy administered 1, 2, 4, 8 or 16 hours after the priming dose. Ten mice at a time were housed in a perspex animal cage and irradiated using Co-60 gamma radiation. For every time point (1, 2, 4, 8 or 16 hours), there were four treatment groups of 5 mice for statistical analysis. The first group acted as a non-irradiated control (0 Gy). The second group of mice received only the priming dose (0.005 Gy), while the third group of mice received only the challenge dose (4 Gy). The fourth group of mice received both the priming and challenge doses 0.005 Gy + 4 Gy). The process was repeated for the second priming dose of 0.01 Gy. A total of 200 mice were used. The animals were sacrificed by cervical dislocation 24 hours after receiving the challenge dose. Both femora were removed and cleared of adhering muscle tissue. The bone marrow cells of five mice were collected and the nucleated cells removed using filtration through a mixed cellulose column incorporating a self-locking filter. The cell suspension was placed onto microscope slides using a cytocentrifuge, air-dried and then stained for the micronuclei. Then the slides were coded, and reticulocytes were scored for the presence or absence of micronuclei. Approximately 2500 cells were scored for each treatment point, and the number of micronuclei counted ranged from 3 to 125 in this sample size. While it appears that the adaptive response may be present in 2 of 9 groups of mice pre-exposed to 0.005 or 0.01 Gy, this

  19. In normal human fibroblasts variation in DSB repair capacity cannot be ascribed to radiation-induced changes in the localisation, expression or activity of major NHEJ proteins

    DEFF Research Database (Denmark)

    Kasten-Pisula, Ulla; Vronskaja, Svetlana; Overgaard, Jens

    2008-01-01

    in the activity of the DNA-PK complex induced upon irradiation. CONCLUSIONS: For normal human fibroblasts, the level or activity of NHEJ proteins measured prior to or after irradiation cannot be used to predict the DSB repair capacity or cellular radiosensitivity. Udgivelsesdato: 2008-Mar......BACKGROUND AND PURPOSE: The aim of the present study was to test whether for normal human fibroblasts the variation in double-strand break (DSB) repair capacity results from radiation-induced differences in localisation, expression or activity of major non-homologous end-joining (NHEJ) proteins....... MATERIALS AND METHODS: Experiments were performed with 11 normal human fibroblast strains AF01-11. NHEJ proteins were determined by Western blot and DNA-PK activity by pulldown-assay. RESULTS: The four NHEJ proteins tested (Ku70, Ku80, XRCC4 and DNA-PKcs) were found to be localised almost exclusively...

  20. Variation of normal tissue complication probability (NTCP) estimates of radiation-induced hypothyroidism in relation to changes in delineation of the thyroid gland

    DEFF Research Database (Denmark)

    Rønjom, Marianne Feen; Brink, Carsten; Laugaard Lorenzen, Ebbe

    2015-01-01

    volume, Dmean and estimated risk of HT. Bland-Altman plots were used for assessment of the systematic (mean) and random [standard deviation (SD)] variability of the three parameters, and a method for displaying the spatial variation in delineation differences was developed. Results. Intra......-observer variability resulted in a mean difference in thyroid volume and Dmean of 0.4 cm(3) (SD ± 1.6) and -0.5 Gy (SD ± 1.0), respectively, and 0.3 cm(3) (SD ± 1.8) and 0.0 Gy (SD ± 1.3) for inter-observer variability. The corresponding mean differences of NTCP values for radiation-induced HT due to intra- and inter...

  1. Variation in U.V. primary fluorescence-intensity of vital cells depending on 60Co γ-radiation dose

    International Nuclear Information System (INIS)

    Merkle, K.

    1978-01-01

    Using impulse-cytofluorophotometry in the ultra-violet spectral region it has been shown on vital, unstained Ehrlich ascites tumour cells that the primary fluorescence intensity of this tumour was on day 11 after transplantation 20 per cent higher than on day 8. Storage of the vital cells for 25 min at 20 0 C had no effect on this result. When the cells were exposed to 60 Co γ-radiation on day 6, a new stable fluorescence level was established after 20 hours. Measurements of the primary fluorescence intensity depending on dose have shown a significant rise starting from 75 rad at 48 hours after irradiation. The fluorescence intensity rose by 42.5 per cent of the control value at 3000 rad, but only by 31.5 per cent on exposure to 4000 rad. (author)

  2. Radiation induced variations in photoperiod-sensitivity, thermo-sensitivity and the number of days to heading in rice

    International Nuclear Information System (INIS)

    Hsieh, S.C.

    1975-01-01

    Radiation induced semi-dwarf mutants derived from five japonica type varieties of rice were studied with regard to their photoperiod-sensitivity, thermo-sensitivity and the number of days to heading. The experiment was carried out under the natural conditions at Taipei. The coefficient of photoperiod-sensitivity and thermo-sensitivity as developed by Oka (1954) were estimated for the mutants in comparison with their original varieties. It was observed that these various physiological characters could be altered easily by mutations. Mutants showed wider ranges in both positive and negative directions than their original varieties in all physiological characters studied. Even though heading date depends on both photoperiod-sensitivity and thermo-sensitivity, it was estimated which of the two contributed more to the induced earliness in each mutant. This offers a basis for selecting early maturing lines of rice

  3. Evaluation of 40K and studies of its variation in occupational radiation workers of TAPS 1-4

    International Nuclear Information System (INIS)

    Nagaraju, G.; Rao, D.D.; Baburajan, A.

    2014-01-01

    Tarapur Maharashtra Site consists of two units (TAPS 1 and 2) of 160 MW(e) BWRs and two units (TAPS 3 and 4) of 540 MW(e) PHWRs in operation. Monitoring and dose assessment of all radiation workers is a regulatory requirement as per radiation safety procedures of operating stations based on AERB guidelines. Internal contamination and committed effective dose (CED) due to internally deposited gamma radionuclides is evaluated based on whole body counting measurements. The predominant nuclides of potential internal contamination continued to be 60 Co, 134+137 Cs and 131 I. Apart from these, natural radionuclide 40 K is also detected in the body of occupational workers. It is one of the most important nutrients distributed throughout the body, mainly in muscle and is an essential element in life process. It is under close homeostatic control in the body and is not influenced by the environmental levels. The daily intake of natural radionuclides of uranium and thorium series is almost negligible compared with that of 40 K, a radioisotope of potassium present to the extent of 0.012 % of natural Potassium. It has a halflife of 1.28 x 10 9 Y and decays by beta emission and electron capture accompanied by 1.46 MeV gamma ray emission with 10.7 % abundance. The specific activity of potassium is 31.5 Bq 40 K per gram of potassium. The paper presents the analysis of 40 K concentration in the workers of vegetarian and Non-vegetarian diet categories

  4. IDENTIFYING COLLISIONAL FAMILIES IN THE KUIPER BELT

    International Nuclear Information System (INIS)

    Marcus, Robert A.; Ragozzine, Darin; Murray-Clay, Ruth A.; Holman, Matthew J.

    2011-01-01

    The identification and characterization of numerous collisional families-clusters of bodies with a common collisional origin-in the asteroid belt has added greatly to the understanding of asteroid belt formation and evolution. More recent study has also led to an appreciation of physical processes that had previously been neglected (e.g., the Yarkovsky effect). Collisions have certainly played an important role in the evolution of the Kuiper Belt as well, though only one collisional family has been identified in that region to date, around the dwarf planet Haumea. In this paper, we combine insights into collisional families from numerical simulations with the current observational constraints on the dynamical structure of the Kuiper Belt to investigate the ideal sizes and locations for identifying collisional families. We find that larger progenitors (r ∼ 500 km) result in more easily identifiable families, given the difficulty in identifying fragments of smaller progenitors in magnitude-limited surveys, despite their larger spread and less frequent occurrence. However, even these families do not stand out well from the background. Identifying families as statistical overdensities is much easier than characterizing families by distinguishing individual members from interlopers. Such identification seems promising, provided the background population is well known. In either case, families will also be much easier to study where the background population is small, i.e., at high inclinations. Overall, our results indicate that entirely different techniques for identifying families will be needed for the Kuiper Belt, and we provide some suggestions.

  5. Sensitivity of three tree ferns during their first phase of life to the variation of solar radiation and water availability in a Mexican cloud forest.

    Science.gov (United States)

    Riaño, Karolina; Briones, Oscar

    2015-09-01

    Regeneration niche differentiation promotes species coexistence and diversity; however, the ecological implications for the initial life phases of the majority of pteridophytes are unknown. We analyzed the sensitivity of gametophytes and juvenile sporophytes of the tree ferns Alsophila firma, Cyathea divergens, and Lophosoria quadripinnata to variation in light and water availability. We evaluated gametophyte desiccation tolerance using saturated salt solutions and gametophyte solar radiation tolerance by direct exposure. We also transplanted juvenile sporophytes in environments with 7% and 23% canopy openness and two watering levels. The response of photosynthetic efficiency and water content suggest that the gametophytes of the three species require high relative humidity, tolerate direct solar radiation for up to 30 min and that the response is not species-dependent. Sporophyte size and gas exchange were greater in the more open site, but decreased watering had a lesser effect on these variables in the more closed site. Relative growth rate correlated with the net assimilation rate and leaf weight ratio. Juvenile sporophytes of A. firma were more shade tolerant, while those of C. divergens and L. quadripinnata acclimatized to both environments. Specialization to humid habitats in the tree fern gametophyte restricts the species to humid forests, while differences in the plasticity of the sporophyte facilitate coexistence of the species. © 2015 Botanical Society of America.

  6. Security Belt for Wireless Implantable Medical Devices.

    Science.gov (United States)

    Kulaç, Selman

    2017-09-19

    In this study, a new protective design compatible with existing non-secure systems was proposed, since it is focused on the secure communication of wireless IMD systems in all transmissions. This new protector is an external wearable device and appears to be a belt fitted around for the patients IMD implanted. However, in order to provide effective full duplex transmissions and physical layer security, some sophisticated transceiver antennas have been placed on the belt. In this approach, beam-focused multi-antennas in optimal positions on the belt are randomly switched when transmissions to the IMD are performed and multi-jammer switching with MRC combining or majority-rule based receiving techniques are applied when transmissions from the IMD are carried out. This approach can also reduce the power consumption of the IMDs and contribute to the prolongation of the IMD's battery life.

  7. A reactor study on a belt-shaped screw pinch

    International Nuclear Information System (INIS)

    Bustraan, M.; Franken, W.M.P.; Klippel, H.Th.; Veringa, H.J.; Verschuur, K.A.

    1979-10-01

    A previous study on a screw-pinch reactor with circular cross section (ECN-16 (1977) or Rijnhuizen report 77-101) has been extended to a belt configuration which allows to raise β to 0.5. The present study starts from the main assumptions and principal constraints of the previous work, but some technical aspects are treated more realistically. More attention has been paid to the modular construction, the non-uniform distribution of the wall loading, the thermo-hydraulics, the design of and the losses in the coil systems, and the energy storage and electric transmission systems. A potential use of the first wall of the blanket as part of the implosion coil system is suggested. Finally, a conceptual design of a reactor, with a cost estimate is given. Numerical results are given of parameter variations around the values for the reference reactor. The belt screw-pinch reactor with resistive coils turns out to be uneconomical because of its low net efficiency and its high capital costs. The application of superconducting coils to reduce the ohmic losses turns out to be a non-viable alternative. A more promising way to improve the energy balance seems to be the alternative scheme of fuel injection during the burn

  8. Global Distribution and Variations of NO Infrared Radiative Flux and Its Responses to Solar Activity and Geomagnetic Activity in the Thermosphere

    Science.gov (United States)

    Tang, Chaoli; Wei, Yuanyuan; Liu, Dong; Luo, Tao; Dai, Congming; Wei, Heli

    2017-12-01

    The global distribution and variations of NO infrared radiative flux (NO-IRF) are presented during 2002-2016 in the thermosphere covering 100-280 km altitude based on Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) data set. For investigating the spatial variations of the mutual relationship between NO-IRF and solar activity, the altitude ranges from 100 km to 280 km are divided into 90 altitude bins, and the latitude regions of 83°S-83°N are divided into 16 latitude bins. By processing about 1.8E9 NO-IRF observation values from about 5E6 vertical nighttime profiles recorded in SABER data set, we obtained more than 4.1E8 samples of NO-IRF. The annual-mean values of NO-IRF are then calculated by all available NO-IRF samples within each latitude and altitude bin. Local latitudinal maxima in NO-IRF are found between 120 and 145 km altitude, and the maximum NO-IRF located at polar regions are 3 times more than that of the minimum at equatorial region. The influences of solar and geomagnetic activity on the spatial variations of NO-IRF are investigated. Both the NO-IRF and its response to solar and geomagnetic activity show nearly symmetric distribution between the two hemispheres. It is demonstrated that the observed changes in NO-IRF at altitudes between 100 and 225 km correlate well with the changes in solar activity. The NO-IRF at solar maximum is about 4 times than that at solar minimum, and the current maximum of NO-IRF in 2014 is less than 70% of the prior maximum in 2001. For the first time, the response ranges of the NO-IRF to solar and geomagnetic activity at different altitudes and latitudes are reported.

  9. Radiative Absorption by Light Absorbing Carbon: Uncertainty, Temporal and Spatial Variation in a Typical Polluted City in Yangtze River Delta

    Science.gov (United States)

    Chen, D.; Zhao, Y.; Lyu, R.

    2017-12-01

    The optical properties of light absorbing carbon (LAC) in atmospheric aerosols, including their uncertainties, temporal change and spatial pattern were studied at suburban, urban and industrial sites in Nanjing, a typical polluted city in Yangtze River Delta (YRD). The optical properties of black carbon (BC) and the uncertainty in radiative absorption of BC were quantified combining cavity attenuated phase shift (CAPS) and thermal-optical techniques. It was found that applying a constant value from previous studies for multiple scattering factor could not well represent the actual absorption characteristics of aerosols in Nanjing. The relative deviation between calculated and measured absorption coefficient of BC was up to 56 ± 34%. A significant positive correlation (R2=0.95) was found between multiple scattering factor (C*) and the mixing state of EC (ECopt/EC) within the ECopt/EC ranged 0.43 0.92 (C*=1.64(ECopt/EC)+1.47, 0.43opt/ECcities with heavy particle pollution, since MSOC served as a surrogate for BrC and EC was measured with reliable and effective methods.

  10. The study of dose variation and change of heart volume using 4D-CT in left breast radiation therapy

    International Nuclear Information System (INIS)

    Park, Seon Mi; Cheon, Geum Seong; Heo, Gyeong Hun; Shin, Sung Pil; Kim, Kwang Seok; Kim, Chang Uk; Kim, Hoi Nam

    2013-01-01

    We investigate the results of changed heart volume and heart dose in the left breast cancer patients while considering the movements of respiration. During the months of March and May in 2012, we designated the 10 patients who had tangential irradiation with left breast cancer in the department of radiation Oncology. With acquired images of free breathing pattern through 3D and 4D CT, we had planed enough treatment filed for covered up the whole left breast. It compares the results of the exposed dose and the volume of heart by DVH (Dose Volume histogram). Although total dose was 50.4 Gy (1.8 Gy/28 fraction), reirradiated 9 Gy (1.8 Gy/5 Fraction) with PTV (Planning Target Volume) if necessary. It compares the results of heart volume and heart dose with the free breathing in 3D CT and 4D CT. It represents the maximum difference volume of heart is 40.5%. In addition, it indicated the difference volume of maximum and minimum, average are 8.8% and 27.9%, 37.4% in total absorbed dose of heart. In case of tangential irradiation (opposite beam) in left breast cancer patients, it is necessary to consider the changed heart volume by the respiration of patient and the heartbeat of patient

  11. Daily variations in the position of the prostate bed in patients with prostate cancer receiving postoperative external beam radiation therapy

    International Nuclear Information System (INIS)

    Kupelian, Patrick A.; Langen, Katja M.; Willoughby, Twyla R.; Wagner, Thomas H.; Zeidan, Omar A.; Meeks, Sanford L.

    2006-01-01

    Purpose: The aim of this study was to evaluate the extent of the variation in the position of the prostate bed with respect to the bony anatomy. Methods and Materials: Four patients were treated to 70 Gy in 35 fractions. Before each fraction, a megavoltage computed tomography (CT) of the prostate bed was obtained, resulting in a total of 140 CT studies. Retrospectively, each CT scan was aligned to the simulation kilovoltage scan based on bony anatomy and the prostate bed. The difference between the 2 alignments was calculated for each scan. Results: The average differences (±1 SD) between the two alignments were 0.06 ± 0.37, 0.10 ± 0.86, and 0.39 ± 1.27 mm in the lateral, longitudinal (SI), and vertical (AP) directions, respectively. Laterally, there was no difference ≥3 mm. The cumulative frequency of SI differences were as follows; ≥3 mm: 3%, ≥4 mm: 1%, and ≥5 mm: 1% (maximum: 5 mm). The cumulative frequency of AP differences were as follows; ≥3 mm: 7%, and ≥4 mm: 3% (maximum: 4 mm). Conclusion: In patients with prostate cancer receiving postoperative radiotherapy, the prostate bed motion relative to the pelvic bony anatomy is of a relatively small magnitude. Significant motion (≥3 mm) is infrequent. However, small differences between the prostate bed and the bony anatomy still exist. This might have implications on treatment margins when daily alignment on bony anatomy is performed

  12. Genetic variations in radiation and chemotherapy drug action pathways and survival in locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy.

    Directory of Open Access Journals (Sweden)

    Huai Liu

    Full Text Available BACKGROUND AND PURPOSE: Treatment outcomes vary greatly in patients with nasopharyngeal carcinoma (NPC. The purpose of this study is to evaluate the influence of radiation and chemotherapy drug action pathway gene polymorphisms on the survival of patients with locoregionally advanced NPC treated with cisplatin- and fluorouracil-based chemoradiotherapy. MATERIAL AND METHODS: Four hundred twenty-one consecutive patients with locoregionally advanced NPC were prospectively recruited. We utilized a pathway approach and examined 18 polymorphisms in 13 major genes. Polymorphisms were detected using the LDR-PCR technique. Multifactor dimensionality reduction (MDR analysis was performed to detect potential gene-gene interaction. RESULTS: After adjustment for clinicopathological characteristics, overall survival was significantly decreased in patients with the MPO rs2243828 CT/CC genotype (HR=2.453, 95% CI, 1.687-3.566, P<0.001. The ERCC1 rs3212986 CC (HR=1.711, 95% CI, 1.135-2.579, P=0.010, MDM2 rs2279744 GT/GG (HR=1.743, 95% CI, 1.086-2.798, P=0.021, MPO rs2243828 CT/CC (HR=3.184, 95% CI, 2.261-4.483, P<0.001 and ABCB1 rs2032582 AT/AA (HR=1.997, 95% CI, 1.086-3.670, P=0.026 genotypes were associated with poor progression-free survival. Prognostic score models based on independent prognostic factors successfully classified patients into low-, intermediate-, and high-risk groups. Furthermore, MDR analysis showed no significant interaction between polymorphisms. CONCLUSIONS: Four single nucleotide polymorphisms were associated with survival in patients with locoregionally advanced NPC treated with cisplatin- and fluorouracil-based chemoradiotherapy. Combining clinical prognostic factors with genetic information was valuable in identifying patients with different risk.

  13. Simulation study of CD variation caused by field edge effects and out-of-band radiation in EUVL

    Science.gov (United States)

    Gao, Weimin; Niroomand, Ardavan; Lorusso, Gian F.; Boone, Robert; Lucas, Kevin; Demmerle, Wolfgang

    2013-09-01

    Although extreme ultraviolet lithography (EUVL) remains a promising candidate for semiconductor device manufacturing of the 1x nm half pitch node and beyond, many technological burdens have to be overcome. The "field edge effect" in EUVL is one of them. The image border region of an EUV mask,also known as the "black border" (BB), reflects a few percent of the incident EUV light, resulting in a leakage of light into neighboring exposure fields, especially at the corner of the field where three adjacent exposures take place. This effect significantly impacts on CD uniformity (CDU) across the exposure field. To avoid this phenomenon, a light-shielding border is introduced by etching away the entire absorber and multi-layer (ML)at the image border region of the EUV mask. In this paper, we present a method of modeling the field edge effect (also called the BB effect) by using rigorous lithography simulation with a calibrated resist model. An additional "flare level" at the field edge is introduced on top of the exposure tool flare map to account for the BB effect. The parameters in this model include the reflectivity and the width of the BB, which are mainly determining the leakage of EUV light and its influence range, respectively. Another parameter is the transition width which represents the half shadow effect of the reticle masking blades. By setting the corresponding parameters, the simulation results match well the experimental results obtained at the imec's NXE:3100 EUV exposure tool. Moreover, these results indicate that the out-of-band (OoB) radiation also contributes to the CDU. Using simulation we can also determine the OoB effect rigorouslyusing the methodology of an "effective mask blank". The study in this paper demonstrates that the impact of BB and OoB effects on CDU can be well predicted by simulations.

  14. Study of CD variation caused by the black border effect and out-of-band radiation in extreme ultraviolet lithography

    Science.gov (United States)

    Gao, Weimin; Niroomand, Ardavan; Lorusso, Gian F.; Boone, Robert; Lucas, Kevin; Demmerle, Wolfgang

    2014-04-01

    Although extreme ultraviolet lithography (EUVL) remains a promising candidate for semiconductor device manufacturing of the 1× nm half pitch node and beyond, many technological burdens have to be overcome. The "field edge effect" in EUVL is one of them. The image border region of an EUV mask, also known as the "black border" (BB), reflects a few percent of the incident EUV light, resulting in a leakage of light into neighboring exposure fields, especially at the corner of the field where three adjacent exposures take place. This effect significantly impacts on critical dimension (CD) uniformity (CDU) across the exposure field. To avoid this phenomenon, a light-shielding border is introduced by etching away the entire absorber and multilayer at the image border region of the EUV mask. We present a method of modeling the field edge effect (also called the BB effect) by using rigorous lithography simulation with a calibrated resist model. An additional "flare level" at the field edge is introduced on top of the exposure tool flare map to account for the BB effect. The parameters in this model include the reflectivity and the width of the BB, which are mainly determining the leakage of EUV light and its influence range, respectively. Another parameter is the transition width which represents the half shadow effect of the reticle masking blades. By setting the corresponding parameters, the simulation results match well the experimental results obtained at the IMEC's NXE:3100 EUV exposure tool. Moreover, these results indicate that the out-of-band (OoB) radiation also contributes to the CDU. Using simulation, we can also determine the OoB effect rigorously using the methodology of an "effective mask blank." The study demonstrates that the impact of BB and OoB effects on CDU can be well predicted by simulations.

  15. Kuiper Belt Dust Grains as a Source of Interplanetary Dust Particles

    Science.gov (United States)

    Liou, Jer-Chyi; Zook, Herbert A.; Dermott, Stanley F.

    1996-01-01

    The recent discovery of the so-called Kuiper belt objects has prompted the idea that these objects produce dust grains that may contribute significantly to the interplanetary dust population. In this paper, the orbital evolution of dust grains, of diameters 1 to 9 microns, that originate in the region of the Kuiper belt is studied by means of direct numerical integration. Gravitational forces of the Sun and planets, solar radiation pressure, as well as Poynting-Robertson drag and solar wind drag are included. The interactions between charged dust grains and solar magnetic field are not considered in the model. Because of the effects of drag forces, small dust grains will spiral toward the Sun once they are released from their large parent bodies. This motion leads dust grains to pass by planets as well as encounter numerous mean motion resonances associated with planets. Our results show that about 80% of the Kuiper belt grains are ejected from the Solar System by the giant planets, while the remaining 20% of the grains evolve all the way to the Sun. Surprisingly, the latter dust grains have small orbital eccentricities and inclinations when they cross the orbit of the Earth. This makes them behave more like asteroidal than cometary-type dust particles. This also enhances their chances of being captured by the Earth and makes them a possible source of the collected interplanetary dust particles; in particular, they represent a possible source that brings primitive/organic materials from the outer Solar System to the Earth. When collisions with interstellar dust grains are considered, however, Kuiper belt dust grains around 9 microns appear likely to be collisionally shattered before they can evolve toward the inner part of the Solar System. The collision destruction can be applied to Kuiper belt grains up to about 50 microns. Therefore, Kuiper belt dust grains within this range may not be a significant part of the interplanetary dust complex in the inner Solar

  16. SMALL MAIN-BELT ASTEROID SPECTROSCOPIC SURVEY, PHASE II

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains visible-wavelength (0.435-0.925 micron) spectra for 1341 main-belt asteroids observed during the second phase of the Small Main-belt Asteroid...

  17. Metallogenic epoch of the Jiapigou gold belt, Jilin Province, China

    Indian Academy of Sciences (India)

    Metallogenic epoch of the Jiapigou gold belt, Jilin Province, China: ... The Jiapigou gold belt is located on the northern margin of the North China Craton, and is one of the ... 29, Xueyuan Road, Beijing 100083, People's Republic of China.

  18. Structural appraisal of the Gadag schist belt from gravity investigations

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    From qualitative analysis of the gravity data, several tectonic features are ... major types of schist belts are identified in the ... Dharwar craton; Gadag schist belt; gravity method; inversion. ..... the Research Associateship of Dr D Himabindu.

  19. First-order control of syntectonic sedimentation on crustal-scale structure of mountain belts

    Science.gov (United States)

    Erdős, Zoltán.; Huismans, Ritske S.; van der Beek, Peter

    2015-07-01

    The first-order characteristics of collisional mountain belts and the potential feedback with surface processes are predicted by critical taper theory. While the feedback between erosion and mountain belt structure has been fairly extensively studied, less attention has been given to the potential role of synorogenic deposition. For thin-skinned fold-and-thrust belts, recent studies indicate a strong control of syntectonic deposition on structure, as sedimentation tends to stabilize the thin-skinned wedge. However, the factors controlling basement deformation below fold-and-thrust belts, as evident, for example, in the Zagros Mountains or in the Swiss Alps, remain largely unknown. Previous work has suggested that such variations in orogenic structure may be explained by the thermotectonic "age" of the deforming lithosphere and hence its rheology. Here we demonstrate that sediment loading of the foreland basin area provides an additional control and may explain the variable basement involvement in orogenic belts. When examining the role of sedimentation, we identify two end-members: (1) sediment-starved orogenic systems with thick-skinned basement deformation in an axial orogenic core and thin-skinned deformation in the bordering forelands and (2) sediment-loaded orogens with thick packages of synorogenic deposits, derived from the axial basement zone, deposited on the surrounding foreland fold-and-thrust belts, and characterized by basement deformation below the foreland. Using high-resolution thermomechanical models, we demonstrate a strong feedback between deposition and crustal-scale thick-skinned deformation. Our results show that the loading effects of syntectonic sediments lead to long crustal-scale thrust sheets beneath the orogenic foreland and explain the contrasting characteristics of sediment-starved and sediment-loaded orogens, showing for the first time how both thin- and thick-skinned crustal deformations are linked to sediment deposition in these

  20. Spontaneous micronucleus frequencies in human peripheral blood lymphocytes as a screening test for an individual variation in a different population and radiation-induced micronucleus induction

    International Nuclear Information System (INIS)

    Kang, Chang-Mo; Jeon, Hye-Jeong; Cho, Chul-Koo

    2004-01-01

    Our studies were to evaluate the role of epigenetic factors in the variation of radiosensitivity on human peripheral blood lymphocytes by measuring the frequencies of micronucleus (MN) from 293 healthy subjects of different population for assessing the radiation health risk in Korea. We analyzed the frequencies of both spontaneous and in vitro 60 Co γ-rays or 50MeV neutron-induced MNs. The frequencies of spontaneous NMs not only vary greatly between individuals, but also working or living areas. The increased levels of cells with spontaneous MNs were observed with an increasing age. The frequencies of spontaneous MNs were significantly higher in females than in males. For both sexes, MN frequency was significantly and positively correlated with age. Age and gender are the most important demographic variables impacting on the MN index. Donors who had ever smoked showed significantly increased frequencies of MNs compared to nonsmokers. The main lifestyle factors influencing the MN index in the subjects are correlated significantly and positively with smoke while measuring the spontaneous frequencies of micronuclei. Therefore, it is evident that with regard to the application of MN assay all future studies to evaluate the association between radiosensitivity and susceptibility for radiation health risks in different populations should take into account the effect of age, gender and lifestyle. For the dose-response study, the induced MNs were observed at all doses, and the numerical changes according to doses. The dose-response curves were fitted with a linear-quadratic forms of the dose, and the results were different for γ-rays and neutrons significantly. Neutrons were more effective than γ-rays in producing MN with a dose-dependent manner. The frequency of MN varies with dose. The RBE for a micronuclei was 2.37 ± 0.17. The results suggested that the MN assay have a high potential to ensure appropriate quality control and a standard documentation protocol, which

  1. DOSIS & DOSIS 3D: radiation measurements with the DOSTEL instruments onboard the Columbus Laboratory of the ISS in the years 2009–2016

    Directory of Open Access Journals (Sweden)

    Berger Thomas

    2017-01-01

    Full Text Available The natural radiation environment in Low Earth Orbit (LEO differs significantly in composition and energy from that found on Earth. The space radiation field consists of high energetic protons and heavier ions from Galactic Cosmic Radiation (GCR, as well as of protons and electrons trapped in the Earth’s radiation belts (Van Allen belts. Protons and some heavier particles ejected in occasional Solar Particle Events (SPEs might in addition contribute to the radiation exposure in LEO. All sources of radiation are modulated by the solar cycle. During solar maximum conditions SPEs occur more frequently with higher particle intensities. Since the radiation exposure in LEO exceeds exposure limits for radiation workers on Earth, the radiation exposure in space has been recognized as a main health concern for humans in space missions from the beginning of the space age on. Monitoring of the radiation environment is therefore an inevitable task in human spaceflight. Since mission profiles are always different and each spacecraft provides different shielding distributions, modifying the radiation environment measurements needs to be done for each mission. The experiments “Dose Distribution within the ISS (DOSIS” (2009–2011 and “Dose Distribution within the ISS 3D (DOSIS 3D” (2012–onwards onboard the Columbus Laboratory of the International Space Station (ISS use a detector suite consisting of two silicon detector telescopes (DOSimetry TELescope = DOSTEL and passive radiation detector packages (PDP and are designed for the determination of the temporal and spatial variation of the radiation environment. With the DOSTEL instruments’ changes of the radiation composition and the related exposure levels in dependence of the solar cycle, the altitude of the ISS and the influence of attitude changes of the ISS during Space Shuttle dockings inside the Columbus Laboratory have been monitored. The absorbed doses measured at the end of May 2016

  2. DOSIS & DOSIS 3D: radiation measurements with the DOSTEL instruments onboard the Columbus Laboratory of the ISS in the years 2009-2016

    Science.gov (United States)

    Berger, Thomas; Burmeister, Sönke; Matthiä, Daniel; Przybyla, Bartos; Reitz, Günther; Bilski, Pawel; Hajek, Michael; Sihver, Lembit; Szabo, Julianna; Ambrozova, Iva; Vanhavere, Filip; Gaza, Ramona; Semones, Edward; Yukihara, Eduardo G.; Benton, Eric R.; Uchihori, Yukio; Kodaira, Satoshi; Kitamura, Hisashi; Boehme, Matthias

    2017-03-01

    The natural radiation environment in Low Earth Orbit (LEO) differs significantly in composition and energy from that found on Earth. The space radiation field consists of high energetic protons and heavier ions from Galactic Cosmic Radiation (GCR), as well as of protons and electrons trapped in the Earth's radiation belts (Van Allen belts). Protons and some heavier particles ejected in occasional Solar Particle Events (SPEs) might in addition contribute to the radiation exposure in LEO. All sources of radiation are modulated by the solar cycle. During solar maximum conditions SPEs occur more frequently with higher particle intensities. Since the radiation exposure in LEO exceeds exposure limits for radiation workers on Earth, the radiation exposure in space has been recognized as a main health concern for humans in space missions from the beginning of the space age on. Monitoring of the radiation environment is therefore an inevitable task in human spaceflight. Since mission profiles are always different and each spacecraft provides different shielding distributions, modifying the radiation environment measurements needs to be done for each mission. The experiments "Dose Distribution within the ISS (DOSIS)" (2009-2011) and "Dose Distribution within the ISS 3D (DOSIS 3D)" (2012-onwards) onboard the Columbus Laboratory of the International Space Station (ISS) use a detector suite consisting of two silicon detector telescopes (DOSimetry TELescope = DOSTEL) and passive radiation detector packages (PDP) and are designed for the determination of the temporal and spatial variation of the radiation environment. With the DOSTEL instruments' changes of the radiation composition and the related exposure levels in dependence of the solar cycle, the altitude of the ISS and the influence of attitude changes of the ISS during Space Shuttle dockings inside the Columbus Laboratory have been monitored. The absorbed doses measured at the end of May 2016 reached up to 286

  3. 30 CFR 75.1108 - Approved conveyor belts.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved conveyor belts. 75.1108 Section 75... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1108 Approved conveyor belts. (a) Until December 31, 2009 conveyor belts placed in service in underground coal mines shall be: (1) Approved under...

  4. Gravity inferred subsurface structure of Gadwal Schist belt, Andhra

    Indian Academy of Sciences (India)

    Detailed gravity data collected across the Gadwal schist belt in the state of Andhra Pradesh show an 8.4 mgal residual gravity anomaly associated with meta-sediments/volcanics of the linear NNW-SSE trending schist belt that shows metamorphism from green schist to amphibolite facies. This schist belt is flanked on either ...

  5. 14 CFR 125.211 - Seat and safety belts.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Seat and safety belts. 125.211 Section 125... Requirements § 125.211 Seat and safety belts. (a) No person may operate an airplane unless there are available... the airplane who is at least 2 years old; and (2) An approved safety belt for separate use by each...

  6. Klippen Belt, Flysch Belt and Inner Western Carpathian Paleogene Basin Relations in the Northern Slovakia by Magnetotelluric Imaging

    Czech Academy of Sciences Publication Activity Database

    Majcin, D.; Bezák, V.; Klanica, Radek; Vozár, J.; Pek, Josef; Bilčík, D.; Telecký, Josef

    (2018) ISSN 0033-4553 Institutional support: RVO:67985530 Keywords : magnetotellurics * Western Carpathians * Klippen Belt * Flysch Belt * Inner Carpathian Paleogene Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 1.591, year: 2016

  7. Composite Microdiscs with a Magnetic Belt

    DEFF Research Database (Denmark)

    Knaapila, Matti; Høyer, Henrik; Helgesen, Geir

    2015-01-01

    , the spontaneous aggregation of composite particles is suppressed when dispersed into liquid, which is attributed to the increased particle size, reduced magnetic susceptibility, and the shape of the magnetic domain distribution within the particles (spherical versus a belt). When the composite particles...

  8. Pregnancy: Should I Use a Seat Belt?

    Science.gov (United States)

    ... passenger has not been shown to affect the safety of an unborn baby in a crash. Injuries from car crashes tend to be less serious in people who are sitting in the back seat. If you are not driving, you may want to sit in the back seat. It is still important to wear a seat belt, no matter where ...

  9. The thrust belts of Western North America

    Energy Technology Data Exchange (ETDEWEB)

    Moulton, F.C.

    1993-08-01

    Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

  10. Design aspects of multiple driven belt conveyors

    NARCIS (Netherlands)

    Nuttall, A.J.G.

    2007-01-01

    Worldwide belt conveyors are used to transport a great variety of bulk solid materials. The desire to carry higher tonnages over longer distances and more diverse routes, while keeping exploitation costs as low as possible, has fuelled many technological advances. An interesting development in the

  11. Energy efficient idler for belt conveyor systems

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, A.K.; Chattopadhyay, A. [Indian School of Mines Univ., Dhanbad (India). Dept. of Mechanical Engineering and Mining; Soni, R.; Bhattnagar, M.

    2009-07-01

    In today's economic and legal environment, energy efficiency has become more important than ever. This paper proposes a new design of idler rollers for belt conveyors that could help to them even more efficient by reducing their energy consumption and also their CO{sub 2} footprint. (orig.)

  12. Belts and Chains. FOS: Fundamentals of Service.

    Science.gov (United States)

    John Deere Co., Moline, IL.

    This manual on belts and chain drives is one of a series of power mechanics texts and visual aids on theory, of operation, diagnosis, and repair of automotive and off-the-road agricultural and construction equipment. Materials provide basic information and illustrations for use by vocational students and teachers as well as shop servicemen and…

  13. Green Belt Europe - borders separate, nature unites

    Science.gov (United States)

    Uwe Friedel

    2015-01-01

    During the period of the Cold War between 1945 and 1989, a "Green Belt" of valuable pristine landscapes developed along the border line between Eastern and Western Europe, the intensively fortified and guarded so called Iron Curtain. Due to the remoteness of the border areas, a high number of national parks and other large conservation areas can be found...

  14. Mafic magmatism in the Bakhuis Granulite Belt

    NARCIS (Netherlands)

    Klaver, M.; de Roever, E.W.F.; Thijssen, A.C.D.; Bleeker, W.; Söderlund, U.; Chamberlain, K.; Ernst, R.; Berndt, J.; Zeh, A.

    2015-01-01

    The Bakhuis Granulite Belt (BGB) is a metamorphic terrain within the Guiana Shield that experienced ultrahigh-temperature (UHT) metamorphism at 2.07–2.05Ga. In the southwest of the BGB, the Kabalebo charnockites were emplaced at ca. 1.99Ga and thus postdate UHT metamorphism by at least 60Myr. Two

  15. Dynamic Settings and Interactions between Basin Subsidence and Orogeny in Zhoukou Depression and Dabie Orogenic Belt

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper presents a study of the geo-dynamic setting and the relation between orogenic uplift and basin subsidence in the inland Zhoukou depression and Dabie orogenic belt. Since the Mesozoic the evolution of Zhoukou depression can be divided into three stages: (1) foreland basin, (2) transitional stage, (3) fault depression. Formation and variations of basin were not only related to the orogenesis, but also consistent with the orogenic uplift.

  16. International survey of seat belt use exemptions.

    Science.gov (United States)

    Weiss, H; Sirin, H; Levine, J A; Sauber, E

    2006-08-01

    Substantial evidence of seatbelt efficacy has been shown by several studies, and it is widely recommended that motor vehicle occupants use properly fitted seat belts. However, some (but a heretofore unknown number of) countries with national seat belt laws permit various exemptions which may lower use rates. The aim of this study was to survey the variety of exemptions to national seat belt laws. This investigation relied on identifying respondents from national traffic safety agencies, other governmental and non-governmental organizations, Internet searches, personal contacts, and other sources. Questionnaires were deployed through a web based survey supplemented by email and postal versions. Responses were received from 30 countries of which 28 (93.7%) had a national seat belt law. About two thirds (63.7%) of the 28 national laws applied to both front and back seat passengers. The leading exemption types included vehicles made before a certain year (n = 13), antique vehicles (n = 12), military vehicles (n = 11), buses (n = 9), and emergency vehicles (n = 8). Most responding countries reported one or more specific categories of individuals as exempt including those with medical exemptions (n = 20), taxi drivers (n = 11), police (n = 9), emergency medical personnel (n = 8), physically disabled people (n = 6), and pregnant women (n = 6). Out of 26 responses to the question regarding current level of enforcement, 42.3% felt enforcement was "very good or good" and 57.7% characterized it as "fair or poor". This study represents one of the largest international traffic law surveys reported. Most national seatbelt laws offer perilous exemptions to a broad array of vehicle types and road user groups. These findings, coupled with concern over the level of enforcement in the majority of countries surveyed, suggest that international road safety efforts have a long way to go to improve coverage and enforcement of national seat belt laws.

  17. VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt

    Directory of Open Access Journals (Sweden)

    Laura Lafon-Hughes

    2014-10-01

    Full Text Available Poly-ADP-ribose (PAR is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs and degraded by poly-ADP-ribose-glycohydrolase (PARG. Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair. Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt. In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO. PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications.

  18. Dynamics Analysis and Modeling of Rubber Belt in Large Mine Belt Conveyors

    Directory of Open Access Journals (Sweden)

    Gao Yang

    2014-10-01

    Full Text Available Rubber belt not only is one of the key components of belt conveyor, but also affects the overall performance of the core part. Research on dynamics analysis of large conveyor not only helps to improve the reliability and design level, but also can guide the rational selection of conveyor safety factor, and effectively reduce the cost of the conveyor belt. Based on unique viscoelastic properties of belt conveyor, it was simplified as one-dimensional viscoelastic rod in this study, and then a discrete element model of conveyor systems was established. The kinetic equations of each discrete unit was derived using kinetic energy, potential energy of driving segment, bearing segment and return segment and equation of energy dissipation and Lagrange equation. Based on Wilson-q algorithm, the kinetic equation of DT1307-type ST2000's conveyor belt was solved by using Matlab to write computer programs. Research on the change rule of conveyor displacement, velocity, acceleration and dynamic tension during the boot process revealed the working mechanism of nonlinear viscoelastic, which lay the theoretical foundation for dynamic performance optimization of large belt conveyor. The calculation results were used to optimize design and analysis of conveyor system, the result showed that it could reduce the driven tension peaks about 12 %, save 5 % of overall manufacturing cost, which bring considerable profits for enterprises.

  19. Determination of relative immobile and sliding areas between carrying and tractive belts in using of belt conveyor intermediate drives

    OpenAIRE

    Goncharov K.A.

    2015-01-01

    Method of determination of relative immobile and sliding areas between carrying and tractive belts in places of mount-ing of belt conveyor intermediate drives made in the form of tractive contours is proposed. The example shows potential of this method in multidrive belt conveyor design process.

  20. Determination of relative immobile and sliding areas between carrying and tractive belts in using of belt conveyor intermediate drives

    Directory of Open Access Journals (Sweden)

    Goncharov K.A.

    2015-12-01

    Full Text Available Method of determination of relative immobile and sliding areas between carrying and tractive belts in places of mount-ing of belt conveyor intermediate drives made in the form of tractive contours is proposed. The example shows potential of this method in multidrive belt conveyor design process.

  1. Quantitative Assessment of CRAND Contribution to the Inner Belt Electron Intensity

    Science.gov (United States)

    Zhang, K.; Li, X.; Selesnick, R.; Schiller, Q. A.; Zhao, H.; Baker, D. N.; Temerin, M. A.

    2017-12-01

    Following the direct identification and measurements of Cosmic Ray Albedo Neutron Decay (CRAND) produced electrons near the inner edge of the inner belt by Colorado Student Space Weather Experiment (CSSWE)1, we extend the study by addressing more comprehensive questions: (1) what is the relative CRAND contribution to the inner belt compared with electrons injected from further out? (2) How does this relative contribution vary with geomagnetic activity and electron energy? (3) What is the solar cycle dependence of CRAND electrons? In order to answer the above questions, extended data of relativistic electrons in the inner belt are needed for a much longer time period and also finer energy resolution is required. Therefore, we will show results regarding the above questions based on data including other low Earth orbit measurements in addition to CSSWE, such as SAMPEX/PET, DEMETER/IDP, and PROBA-V/EPT. [1] Li, Xinlin, Richard Selesnick, Quintin Schiller, Kun Zhang, Hong Zhao, Daniel Baker, and Michael Temerin (2017), Direct detection of albedo neutron decay electrons at the inner edge of the radiation belt and determination of neutron density in near-Earth space, Nature, under review.

  2. Method of monitoring, inspecting or testing conveyor belts

    International Nuclear Information System (INIS)

    Van der Walt, A.J.

    1985-01-01

    An invention is discussed which provides a method, installation and kit for monitoring, inspecting or testing a conveyor belt. Provision is made to transmit penetrating rays such as X-rays through a moving conveyor belt, forming a visible moving image from rays transmitted through the belt, and visually inspecting such moving image, after recording it if desired, to ascertain the condition of the interior of the belt. Typically an X-ray tube head is used to transmit the rays through the belt to a fluorescent screen which forms the image. The moving image can be recorded by means of a video camera

  3. Near Real-Time Assessment of Anatomic and Dosimetric Variations for Head and Neck Radiation Therapy via Graphics Processing Unit–based Dose Deformation Framework

    Energy Technology Data Exchange (ETDEWEB)

    Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Santhanam, Anand; Neylon, John; Min, Yugang; Armstrong, Tess; Sheng, Ke [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Staton, Robert J.; Pukala, Jason [Department of Radiation Oncology, UF Health Cancer Center - Orlando Health, Orlando, Florida (United States); Pham, Andrew; Low, Daniel A.; Lee, Steve P. [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Steinberg, Michael; Manon, Rafael [Department of Radiation Oncology, UF Health Cancer Center - Orlando Health, Orlando, Florida (United States); Chen, Allen M.; Kupelian, Patrick [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States)

    2015-06-01

    Purpose: The purpose of this study was to systematically monitor anatomic variations and their dosimetric consequences during intensity modulated radiation therapy (IMRT) for head and neck (H&N) cancer by using a graphics processing unit (GPU)-based deformable image registration (DIR) framework. Methods and Materials: Eleven IMRT H&N patients undergoing IMRT with daily megavoltage computed tomography (CT) and weekly kilovoltage CT (kVCT) scans were included in this analysis. Pretreatment kVCTs were automatically registered with their corresponding planning CTs through a GPU-based DIR framework. The deformation of each contoured structure in the H&N region was computed to account for nonrigid change in the patient setup. The Jacobian determinant of the planning target volumes and the surrounding critical structures were used to quantify anatomical volume changes. The actual delivered dose was calculated accounting for the organ deformation. The dose distribution uncertainties due to registration errors were estimated using a landmark-based gamma evaluation. Results: Dramatic interfractional anatomic changes were observed. During the treatment course of 6 to 7 weeks, the parotid gland volumes changed up to 34.7%, and the center-of-mass displacement of the 2 parotid glands varied in the range of 0.9 to 8.8 mm. For the primary treatment volume, the cumulative minimum and mean and equivalent uniform doses assessed by the weekly kVCTs were lower than the planned doses by up to 14.9% (P=.14), 2% (P=.39), and 7.3% (P=.05), respectively. The cumulative mean doses were significantly higher than the planned dose for the left parotid (P=.03) and right parotid glands (P=.006). The computation including DIR and dose accumulation was ultrafast (∼45 seconds) with registration accuracy at the subvoxel level. Conclusions: A systematic analysis of anatomic variations in the H&N region and their dosimetric consequences is critical in improving treatment efficacy. Nearly real

  4. Modeling of the radiation belt megnetosphere in decisional timeframes

    Science.gov (United States)

    Koller, Josef; Reeves, Geoffrey D; Friedel, Reiner H.W.

    2013-04-23

    Systems and methods for calculating L* in the magnetosphere with essentially the same accuracy as with a physics based model at many times the speed by developing a surrogate trained to be a surrogate for the physics-based model. The trained model can then beneficially process input data falling within the training range of the surrogate model. The surrogate model can be a feedforward neural network and the physics-based model can be the TSK03 model. Operatively, the surrogate model can use parameters on which the physics-based model was based, and/or spatial data for the location where L* is to be calculated. Surrogate models should be provided for each of a plurality of pitch angles. Accordingly, a surrogate model having a closed drift shell can be used from the plurality of models. The feedforward neural network can have a plurality of input-layer units, there being at least one input-layer unit for each physics-based model parameter, a plurality of hidden layer units and at least one output unit for the value of L*.

  5. Persistence of Salmonella on egg conveyor belts is dependent on the belt type but not on the rdar morphotype.

    Science.gov (United States)

    Stocki, S L; Annett, C B; Sibley, C D; McLaws, M; Checkley, S L; Singh, N; Surette, M G; White, A P

    2007-11-01

    Commercial caged layer flocks in Alberta, Canada, are commonly monitored for Salmonella enterica serovar Enteritidis (SE) and S. enterica serovar Typhimurium (ST) by environmental sampling. In one recent case, a SE strain isolated from the egg conveyor belt was a source of persistent infection for the flock. This study was undertaken to examine Salmonella colonization on egg conveyor belts and to determine whether the rdar morphotype, a conserved physiology associated with aggregation and long-term survival, contributed to persistence. Four woven belts constructed of natural or nonnatural fibers and a 1-piece belt made of vinyl were tested with rdar-positive ST and SE strains and a rdar-negative ST DeltaagfD reference strain. The type of egg belt was the most important factor influencing Salmonella colonization and persistence. The vinyl belt, with the least surface area available for colonization, had the fewest Salmonella remaining after washing and disinfection, whereas the hemp-plastic belt, with the greatest surface area, had the most Salmonella remaining. Real-time gene expression indicated that the rdar morphotype was involved in colonizing the egg belt pieces; however, it was not essential for persistence. In addition, rdar-positive and rdar-negative strains were equally similarly to disinfection on the egg belt pieces. The results indicate that Salmonella can persist on a variety of egg belts by mechanisms other than the rdar morphotype, and that using egg conveyer belts with reduced surface area for bacterial colonization can lessen contamination problems.

  6. Radiation hematology

    International Nuclear Information System (INIS)

    Zherbin, E.A.; Chukhlovin, A.B.

    1989-01-01

    State-of-the-Art ofl radiation hematology and review of the problems now facing this brauch of radiobiology and nuclear medicine are presented. Distortion of division and maturation of hemopoiesis parent cells is considered as main factor of radiopathology for hematopoetic system. Problems of radiation injury and functional variation of hematopoetic microenvironment cell populations are discussed. 176 figs.; 23 figs.; 18 tabs

  7. Energy spectra variations of high energy electrons in magnetic storms observed by ARASE and HIMAWARI

    Science.gov (United States)

    Takashima, T.; Higashio, N.; Mitani, T.; Nagatsuma, T.; Yoshizumi, M.

    2017-12-01

    The ARASE spacecraft was launched in December 20, 2016 to investigate mechanisms for acceleration and loss of relativistic electrons in the radiation belts during space storms. The six particle instruments with wide energy range (a few eV to 10MeV) are onboard the ARASE spacecraft. Especially, two particle instruments, HEP and XEP observe high energy electron with energy range from 70keV to over 10Mev. Those instruments observed several geomagnetic storms caused by coronal hole high speed streams or coronal mass ejections from March in 2017. The relativistic electrons in the outer radiation belt were disappeared/increased and their energy spectra were changed dynamically in some storms observed by XEP/HEP onboard the ARASE spacecraft. In the same time, SEDA-e with energy range 200keV-4.5MeV for electron on board the HIMAWARI-8, Japanese weather satellite on GEO, observed increase of relativistic electron in different local time. We will report on energy spectra variations of high energy electrons including calibrations of differential flux between XEP and HEP and discuss comparisons with energy spectra between ARAE and HIMAWARI that observed each storm in different local time.

  8. Asteroid family dynamics in the inner main belt

    Science.gov (United States)

    Dykhuis, Melissa Joy

    The inner main asteroid belt is an important source of near-Earth objects and terrestrial planet impactors; however, the dynamics and history of this region are challenging to understand, due to its high population density and the presence of multiple orbital resonances. This dissertation explores the properties of two of the most populous inner main belt family groups --- the Flora family and the Nysa-Polana complex --- investigating their memberships, ages, spin properties, collision dynamics, and range in orbital and reflectance parameters. Though diffuse, the family associated with asteroid (8) Flora dominates the inner main belt in terms of the extent of its members in orbital parameter space, resulting in its significant overlap with multiple neighboring families. This dissertation introduces a new method for membership determination (the core sample method) which enables the distinction of the Flora family from the background, permitting its further analysis. The Flora family is shown to have a signature in plots of semimajor axis vs. size consistent with that expected for a collisional family dispersed as a result of the Yarkovsky radiation effect. The family's age is determined from the Yarkovsky dispersion to be 950 My. Furthermore, a survey of the spin sense of 21 Flora-region asteroids, accomplished via a time-efficient modification of the epoch method for spin sense determination, confirms the single-collision Yarkovsky-dispersed model for the family's origin. The neighboring Nysa-Polana complex is the likely source region for many of the carbonaceous near-Earth asteroids, several of which are important targets for spacecraft reconnaissance and sample return missions. Family identification in the Nysa-Polana complex via the core sample method reveals two families associated with asteroid (135) Hertha, both with distinct age and reflectance properties. The larger of these two families demonstrates a correlation in semimajor axis and eccentricity

  9. 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.

  10. Drivers' attitudes toward front or rear child passenger belt use and seat belt reminders at these seating positions.

    Science.gov (United States)

    Kidd, David G; McCartt, Anne T

    2014-01-01

    Passengers, especially those in rear seating positions, use seat belts less frequently than drivers. In-vehicle technology can inform drivers when their passengers are unbuckled and encourage passengers to use belts. The current study collected information about drivers' attitudes toward passenger belt use and belt reminders for front passengers and children in back seats. A national telephone survey of 1218 people 18 and older was conducted, of which 477 respondents were drivers who transport a front seat passenger at least once a week and 254 were drivers who transport an 8- to 15-year-old child in the back seat. Respondents were asked about their attitudes toward belt use by their front passengers or rear child passengers and preferences for different passenger belt reminder features. Ninety percent of drivers who regularly transport front seat passengers said that the passengers always use seat belts. Reported belt use was even higher among 8- to 15-year-old children in the back seat (97%). Among the drivers whose children do not always buckle up, about half said their child unbuckled the belt during the trip. Almost every full-time belt use driver (96%) would encourage front passengers to buckle up if not belted, compared to 57 percent of part-time belt users and nonusers. In contrast, nearly every driver who transports children in the back seat would encourage their belt use, regardless of the driver's belt use habits. Most drivers who transport front passengers wanted passenger belt reminders to encourage passengers to buckle up. Most of these drivers wanted a chime/buzzer or warning light or text display and wanted the reminder to last indefinitely. Most drivers who transport child passengers in the rear seat wanted the vehicle to indicate whether child passengers are unbuckled. A large majority of these drivers wanted notifications via a visual diagram of seating positions and belt use, a chime/buzzer, and a warning light or text display. These drivers

  11. Understanding quaternions and the Dirac belt trick

    International Nuclear Information System (INIS)

    Staley, Mark

    2010-01-01

    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.

  12. Araguaia fold belt, new geochronological data

    International Nuclear Information System (INIS)

    Lafon, J.M.; Macambira, J.B.; Macambira, M.J.B.; Moura, C.A.V.; Souza, A.C.C.

    1990-01-01

    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)

  13. Quantifying the spatial and temporal variation in dose from external exposure to radiation: a new tool for use on free-ranging wildlife

    International Nuclear Information System (INIS)

    Hinton, Thomas G.; Byrne, Michael E.; Webster, Sarah; Beasley, James C.

    2015-01-01

    Inadequate dosimetry is often the fundamental problem in much of the controversial research dealing with radiation effects on free-ranging wildlife. Such research is difficult because of the need to measure dose from several potential pathways of exposure (i.e., internal contamination, external irradiation, and inhalation). Difficulties in quantifying external exposures can contribute significantly to the uncertainties of dose-effect relationships. Quantifying an animal's external exposure due to spatial–temporal use of habitats that can vary by orders of magnitude in radiation levels is particularly challenging. Historically, wildlife dosimetry studies have largely ignored or been unable to accurately quantify variability in external dose because of technological limitations. The difficulties of quantifying the temporal–spatial aspects of external irradiation prompted us to develop a new dosimetry instrument for field research. We merged two existing technologies [Global Positioning Systems (GPS) and electronic dosimeters] to accommodate the restrictive conditions of having a combined unit small enough to be unobtrusively worn on the neck of a free-ranging animal, and sufficiently robust to withstand harsh environmental conditions. The GPS–dosimeter quantifies the spatial and temporal variation in external dose as wildlife traverse radioactively contaminated habitats and sends, via satellites, an animal's location and short term integrated dose to the researcher at a user-defined interval. Herein we describe: (1) the GPS–dosimeters; (2) tests to compare their uniformity of response to external irradiation under laboratory conditions; (3) field tests of their durability when worn on wildlife under natural conditions; and (4) a field application of the new technology at a radioactively contaminated site. Use of coupled GPS–dosimetry will allow, for the first time, researchers to better understand the relationship of animals to their contaminated

  14. Aortic ruptures in seat belt wearers.

    Science.gov (United States)

    Arajärvi, E; Santavirta, S; Tolonen, J

    1989-09-01

    Several investigations have indicated that rupture of the thoracic aorta is one of the leading causes of immediate death in victims of road traffic accidents. In Finland in 1983, 92% of front-seat passengers were seat belt wearers on highways and 82% in build-up areas. The mechanisms of rupture of the aorta have been intensively investigated, but the relationship between seat belt wearing and injury mechanisms leading to aortic rupture is still largely unknown. This study comprises 4169 fatally injured victims investigated by the Boards of Traffic Accident Investigation of Insurance Companies during the period 1972 to 1985. Chest injuries were recorded as the main cause of death in 1121 (26.9%) victims, 207 (5.0%) of those victims having worn a seat belt. Aortic ruptures were found at autopsy in 98 victims and the exact information of the location of the aortic tears was available in 68. For a control group, we analyzed 72 randomly chosen unbelted victims who had a fatal aortic rupture in similar accidents. The location of the aortic rupture in unbelted victims was more often in the ascending aorta, especially in drivers, whereas in seat belt wearers the distal descending aorta was statistically more often ruptured, especially in right-front passengers (p less than 0.05). The steering wheel predominated statistically as the part of the car estimated to have caused the injury in unbelted victims (37/72), and some interior part of the car was the most common cause of fatal thoracic impacts in seat belt wearers (48/68) (p less than 0.001). The mechanism of rupture of the aorta in the classic site just distal to the subclavian artery seems to be rapid deceleration, although complex body movements are also responsible in side impact collisions. The main mechanism leading to rupture of the ascending aorta seems to be severe blow to the bony thorax. This also often causes associated thoracic injuries, such as heart rupture and sternal fracture. Injuries in the ascending

  15. Arc magmatism as a window to plate kinematics and subduction polarity: Example from the eastern Pontides belt, NE Turkey

    Directory of Open Access Journals (Sweden)

    Yener Eyuboglu

    2011-01-01

    Full Text Available The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on recent information from this belt. We infer a southward subduction for the origin of the Eastern Pontides orogenic belt and its associated late Mesozoic–Cenozoic magmatism based on clear spatial and temporal variations in Late Cretaceous and Cenozoic arc magmatism, together with the existence of a prominent south-dipping reverse fault system along the entire southern coast of the Black Sea. Our model is at variance with some recent proposals favoring a northward subduction polarity, and illustrates the importance of arc magmatism in evaluating the geodynamic milieu associated with convergent margin processes.

  16. Variations observed in the respiratory activity of potato tubers (Solanum tuberosum L.) after a treatment with gamma radiation; Variaciones observadas en la actividad respiratoria de tuberculos de patata (Solanum tuberosum L.) despues de un tratamiento con radiacion GAMMA

    Energy Technology Data Exchange (ETDEWEB)

    Mazon Matanzo, M P; Fernandez Gonzalez, J

    1976-07-01

    The present work studies the variations in the respiratory activity of irradiated and IPC treated potato tubers during a storage period of five months. By immediate effect of gamma radiation we can observe an increase in the oxygen consumption of the parenchyma in relation with the control tubers, such increase persists even fours months after gamma radiation. The respiratory activity is reduced in the IPC treated tubers. In the tissues cultivated in vitro the respiratory activity increases at the end of the cultivation period, not only in the control tissues but also in the irradiated ones, though this increase is greater in the control tissues. (Author) 15 refs.

  17. Ore sorting using natural gamma radiation

    International Nuclear Information System (INIS)

    Clark, G.J.; Dickson, B.L.; Gray, F.E.

    1980-01-01

    A method of sorting an ore which emits natural gamma radiation is described, comprising the steps of: (a) mining the ore, (b) placing, substantially at the mining location, the sampled or mined ore on to a moving conveyor belt, (c) measuring the natural gamma emission, water content and mass of the ore while the ore is on the conveyor belt, (d) using the gamma, water content and mass measurements to determine the ore grade, and (e) directing the ore to a location characteristic of its grade when it leaves the conveyor belt

  18. Regional magnetic anomalies, crustal strength, and the location of the northern Cordilleran fold-and-thrust belt

    Science.gov (United States)

    Saltus, R.W.; Hudson, T.L.

    2007-01-01

    The northern Cordilleran fold-and-thrust belt in Canada and Alaska is at the boundary between the broad continental margin mobile belt and the stable North American craton. The fold-and-thrust belt is marked by several significant changes in geometry: cratonward extensions in the central Yukon Territory and northeastern Alaska are separated by marginward re-entrants. These geometric features of the Cordilleran mobile belt are controlled by relations between lithospheric strength and compressional tectonic forces developed along the continental margin. Regional magnetic anomalies indicate deep thermal and compositional characteristics that contribute to variations in crustal strength. Our detailed analysis of one such anomaly, the North Slope deep magnetic high, helps to explain the geometry of the fold-and-thrust front in northern Alaska. This large magnetic anomaly is inferred to reflect voluminous mafic magmatism in an old (Devonian?) extensional domain. The presence of massive amounts of malic material in the lower crust implies geochemical depletion of the underlying upper mantle, which serves to strengthen the lithosphere against thermal erosion by upper mantle convection. We infer that deep-source magnetic highs are an important indicator of strong lower crust and upper mantle. This stronger lithosphere forms buttresses that play an important role in the structural development of the northern Cordilleran fold-and-thrust belt. ?? 2007 The Geological Society of America.

  19. Paleogeographic and Depositional Model for the Neogene fluvial succession, Pishin Belt Northwest Pakistan

    DEFF Research Database (Denmark)

    Kasi, Aimal Khan; Kassi, Akhtar Muhammad; Umar, Muhammad

    2017-01-01

    Miocene subaerial sedimentation started after the final closure of Katawaz Remnant Ocean. Based on detailed field data twelve facies were recognized in Neogene successions exposed in Pishin Belt. These facies were further organized into four facies associations i.e. channels, crevasse splay, natural levee...... and floodplain facies associations. Facies associations and variations provided ample evidences to recognize number of fluvial architectural components in the succession e.g., low-sinuosity sandy braided river, mixed-load meandering, high-sinuosity meandering channels, single-story sandstone and/or conglomerate...... channels, lateral accretion surfaces (point bars) and alluvial fans. Neogene sedimentation in the Pishin Belt was mainly controlled by active tectonism and thrusting in response to oblique collision of the Indian Plate with Afghan Block of the Eurasian Plate along the Chaman-Nushki Fault. Post Miocene...

  20. Granulite belts of Central India with special reference to the Bhopalpatnam Granulite Belt: Significance in crustal evolution and implications for Columbia supercontinent

    Science.gov (United States)

    Vansutre, Sandeep; Hari, K. R.

    2010-11-01

    The Central Indian collage incorporates the following major granulite belts: (1) the Balaghat-Bhandara Granulite Belt (BBG), (2) the Ramakona-Katangi Granulite Belt (RKG), (3) the Chhatuabhavna Granulite (CBG) of Bilaspur-Raigarh Belt, (4) the Makrohar Granulite Belt (MGB) of Mahakoshal supracrustals, (5) the Kondagaon Granulite Belt (KGGB), (6) the Bhopalpatnam Granulite Belt (BGB), (7) the Konta Granulite Belt (KTGB) and (8) the Karimnagar Granulite Belt (KNGB) of the East Dharwar Craton (EDC). We briefly synthesize the general geologic, petrologic and geochronologic features of these belts and explain the Precambrian crustal evolution in Central India. On the basis of the available data, a collisional relationship between Bastar craton and the EDC during the Paleo-Mesoproterozoic is reiterated as proposed by the earlier workers. The tectonic evolution of only few of the orogenic belts (BGB in particular) of Central India is related to Columbia.

  1. Belt conveyor dynamics in transient operation for speed control

    OpenAIRE

    He, D.; Pang, Y.; Lodewijks, G.

    2016-01-01

    Belt conveyors play an important role in continuous dry bulk material transport, especially at the mining industry. Speed control is expected to reduce the energy consumption of belt conveyors. Transient operation is the operation of increasing or decreasing conveyor speed for speed control. According to literature review, current research rarely takes the conveyor dynamics in transient operation into account. However, in belt conveyor speed control, the conveyor dynamic behaviors are signifi...

  2. Seat Belt Use Intention among Brazilian Undergraduate Students

    OpenAIRE

    TORQUATO, RENATA; FRANCO, CLÁUDIO M. A; BIANCHI, ALESSANDRA

    2012-01-01

    The objectives of this study were to explore self-reported seat belt use and group differences in different scenarios in a Brazilian sample and research the variables related to it. 120 college students answered a questionnaire with variables from the theory of planned behavior in order to evaluate the intention of seat belt use among car occupants. Results indicated that attitude and intention were the variables that most contributed to explaining seat belt use. Intention was highly correlat...

  3. Online analysis of coal on a conveyor belt by use of machine vision and kernel methods

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, C.; Jemwa, G.T.; van Dyk, J.C.; Keyser, M.J.; van Heerden, J.H.P. [University of Stellenbosch, Stellenbosch (South Africa). Dept. of Process Engineering

    2010-07-01

    The objective of this project is to explore the use of image analysis to quantify the amount of fines (6mm) present for different coal samples under conditions simulating the coal on conveyor belts similar to those being used by Sasol for gasification purposes. Quantification of the fines will be deemed particularly successful, if the fines mass fraction, as determined by sieve analysis, is possible to be predicted with an error of less than 10%. In this article, kernel-based methods to estimate particle size ranges on a pilot-scale conveyor belt as well as edge detection algorithms are considered. Preliminary results have shown that the fines fraction in the coal on the conveyor belt could be estimated with a median error of approximately 24.1%. This analysis was based on a relatively small number of sieve samples (18 in total) and needs to be validated by more samples. More samples would also facilitate better calibration and may lead to improved estimates of the sieve fines fractions. Similarly, better results may also be possible by using different approaches to image acquisition and analysis. Most of the error in the fines estimates can be attributed to sampling and to fines that were randomly obscured by the top layer (of larger particles) of coal on the belt. Sampling errors occurred as a result of some breakage of the coal between the sieve analyses and the acquisition of the images. The percentage of the fines obscured by the top layer of the coal probably caused most of the variation in the estimated mass of fines, but this needs to be validated experimentally. Preliminary studies have indicated that some variation in the lighting conditions have a small influence on the reliability of the estimates of the coal fines fractions and that consistent lighting conditions are more important than optimal lighting conditions.

  4. 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.

  5. Colors of Inner Disk Classical Kuiper Belt Objects

    Science.gov (United States)

    Romanishin, W.; Tegler, S. C.; Consolmagno, G. J.

    2010-07-01

    We present new optical broadband colors, obtained with the Keck 1 and Vatican Advanced Technology telescopes, for six objects in the inner classical Kuiper Belt. Objects in the inner classical Kuiper Belt are of interest as they may represent the surviving members of the primordial Kuiper Belt that formed interior to the current position of the 3:2 resonance with Neptune, the current position of the plutinos, or, alternatively, they may be objects formed at a different heliocentric distance that were then moved to their present locations. The six new colors, combined with four previously published, show that the ten inner belt objects with known colors form a neutral clump and a reddish clump in B-R color. Nonparametric statistical tests show no significant difference between the B-R color distribution of the inner disk objects compared to the color distributions of Centaurs, plutinos, or scattered disk objects. However, the B-R color distribution of the inner classical Kuiper Belt Objects does differ significantly from the distribution of colors in the cold (low inclination) main classical Kuiper Belt. The cold main classical objects are predominately red, while the inner classical belt objects are a mixture of neutral and red. The color difference may reveal the existence of a gradient in the composition and/or surface processing history in the primordial Kuiper Belt, or indicate that the inner disk objects are not dynamically analogous to the cold main classical belt objects.

  6. Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

    Science.gov (United States)

    Barclay, John A.; Stewart, Walter F.; Henke, Michael D.; Kalash, Kenneth E.

    1987-01-01

    A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.