WorldWideScience

Sample records for atmospheric neutron environments

  1. Single event phenomena in atmospheric neutron environments

    International Nuclear Information System (INIS)

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

  2. A Model of the Cosmic Ray Induced Atmospheric Neutron Environment

    OpenAIRE

    Kole, Merlin; Pearce, Mark; Salinas, Maria Muñoz

    2014-01-01

    In order to optimise the design of space instruments making use of detection materials with low atomic numbers, an understanding of the atmospheric neutron environment and its dependencies on time and position is needed. To produce a simple equation based model, Monte Carlo simulations were performed to obtain the atmospheric neutron fluxes produced by charged galactic cosmic ray interactions with the atmosphere. Based on the simulation results the omnidirectional neutron environment was para...

  3. A Model of the Cosmic Ray Induced Atmospheric Neutron Environment

    CERN Document Server

    Kole, Merlin; Salinas, Maria Muñoz

    2014-01-01

    In order to optimise the design of space instruments making use of detection materials with low atomic numbers, an understanding of the atmospheric neutron environment and its dependencies on time and position is needed. To produce a simple equation based model, Monte Carlo simulations were performed to obtain the atmospheric neutron fluxes produced by charged galactic cosmic ray interactions with the atmosphere. Based on the simulation results the omnidirectional neutron environment was parametrised including dependencies on altitude, magnetic latitude and solar activity. The upward- and downward-moving component of the atmospheric neutron flux are considered separately. The energy spectra calculated using these equations were found to be in good agreement with data from a purpose built balloon-borne neutron detector, high altitude aircraft data and previously published simulation based spectra.

  4. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere.

    Science.gov (United States)

    Makowska, Małgorzata G; Theil Kuhn, Luise; Cleemann, Lars N; Lauridsen, Erik M; Bilheux, Hassina Z; Molaison, Jamie J; Santodonato, Louis J; Tremsin, Anton S; Grosse, Mirco; Morgano, Manuel; Kabra, Saurabh; Strobl, Markus

    2015-12-01

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components. PMID:26724075

  5. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Makowska, Małgorzata G., E-mail: malg@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde 4000 (Denmark); European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Theil Kuhn, Luise; Cleemann, Lars N. [Department of Energy Conversion and Storage, Technical University of Denmark, Roskilde 4000 (Denmark); Lauridsen, Erik M. [Xnovo Technology ApS, Galoche Alle 15, Køge 4600 (Denmark); Bilheux, Hassina Z.; Molaison, Jamie J.; Santodonato, Louis J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Tremsin, Anton S. [Space Sciences Laboratory, University of California at Berkeley, Berkeley, California 94720 (United States); Grosse, Mirco [Institute for Applied Material Research, Karlsruhe Institute of Technology, Karlsruhe DE-76021 (Germany); Morgano, Manuel [Paul Scherrer Institut, Villigen PSI CH-5232 (Switzerland); Kabra, Saurabh [ISIS, Rutherford Appleton Laboratory, Chilton OX11 0QX (United Kingdom); Strobl, Markus [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden)

    2015-12-15

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components.

  6. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    International Nuclear Information System (INIS)

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components

  7. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    DEFF Research Database (Denmark)

    Makowska, Malgorzata G.; Kuhn, Luise Theil; Cleemann, Lars Nilausen;

    2015-01-01

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible...... with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 ◦C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging...... with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of...

  8. Atmospheric neutrons

    International Nuclear Information System (INIS)

    Additional calibrations of the University of California double-scatter neutron and additional analysis corrections lead to the slightly changed neutron fluxes reported here. The theoretical angular distributions of Merker (1975) are in general agreement with our experimental fluxes but do not give the peaks for vertical upward and downward moving neutrons. The theoretical neutron escape current J2/sub pi/ (Merker, 1972; Armstrong et al., 1973) is in agreement with the experimental values from 10 to 100 MeV. Our experimental fluxes agree with those of the Kanbach et al. (1974) in the overlap region from 70 to 100 MeV

  9. Carbon neutron star atmospheres

    CERN Document Server

    Suleimanov, V F; Pavlov, G G; Werner, K

    2013-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in CasA, a pure carbon atmosphere has recently been suggested by Ho & Heinke (2009). To test such a composition for other similar sources, a publicly available detailed grid of carbon model atmosphere spectra is needed. We have computed such a grid using the standard LTE approximation and assuming that the magnetic field does not exceed 10^8 G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra.

  10. Therapeutic potential of atmospheric neutrons

    International Nuclear Information System (INIS)

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

  11. Fast neutron environments.

    Energy Technology Data Exchange (ETDEWEB)

    Buchheit, Thomas Edward; Kotula, Paul Gabriel; Lu, Ping; Brewer, Luke N. (Naval Postgraduate School, Monterey, CA); Goods, Steven Howard (Sandia National Laboratories, Livermore, CA); Foiles, Stephen Martin; Puskar, Joseph David; Hattar, Khalid Mikhiel; Doyle, Barney Lee; Boyce, Brad Lee; Clark, Blythe G.

    2011-10-01

    The goal of this LDRD project is to develop a rapid first-order experimental procedure for the testing of advanced cladding materials that may be considered for generation IV nuclear reactors. In order to investigate this, a technique was developed to expose the coupons of potential materials to high displacement damage at elevated temperatures to simulate the neutron environment expected in Generation IV reactors. This was completed through a high temperature high-energy heavy-ion implantation. The mechanical properties of the ion irradiated region were tested by either micropillar compression or nanoindentation to determine the local properties, as a function of the implantation dose and exposure temperature. In order to directly compare the microstructural evolution and property degradation from the accelerated testing and classical neutron testing, 316L, 409, and 420 stainless steels were tested. In addition, two sets of diffusion couples from 316L and HT9 stainless steels with various refractory metals. This study has shown that if the ion irradiation size scale is taken into consideration when developing and analyzing the mechanical property data, significant insight into the structural properties of the potential cladding materials can be gained in about a week.

  12. Neutron propagation from solar flare in the solar atmosphere

    International Nuclear Information System (INIS)

    Some characteristics of neutron propagation caused by instantaneous point source in the atmosphere of the Sun are calculated. Calculation is performed in different approximations. Effect of the form of substance concentration dependence on the height on the thermal neutron depth distribution density is revealed. It is found that 90% of neutrons give their energy to the environment in the depth interval of the order of several hundred kilometers. Shares of neutron quantity, escaping from the solar atmosphere to the surrounding space, are calculated. 19 refs.; 9 figs.; 5 tabs

  13. Neutrons in natural environment

    International Nuclear Information System (INIS)

    A detecting system for environmental neutrons has to be characterized by a very low inherent background. The details are reported of measuring the background of a 3He proportional counter in a polythene sphere in the Asse salt mine. A spherical counter with 40 mm ext. diameter, filled with 100 kPa 3He and 53 kPa Xe was used. The inherent background of the counter was found to be less then 1 nSv per 24 hours, being less than 1% of the natural neutron radiation level at the ground level. The ambient dose equivalent due to environmental neutrons was estimated at 100-200 nSv per 24 hours. A 3He proportional counter in a polythene sphere was thus found to be sufficiently sensitive to estimate the neutron component at environmental levels. (A.K.)

  14. Space and Atmospheric Environments

    Science.gov (United States)

    Barth, Janet L.; Day, John H. (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides information on space environments and the protection of materials and structures from their harsh conditions. Space environments are complex, and the complexity of spacecraft systems is increasing. Design accommodation must be realistic. Environmental problems can be limited at low cost relative to spacecraft cost.

  15. Atmospheric Disturbance Environment Definition

    Science.gov (United States)

    Tank, William G.

    1994-01-01

    Traditionally, the application of atmospheric disturbance data to airplane design problems has been the domain of the structures engineer. The primary concern in this case is the design of structural components sufficient to handle transient loads induced by the most severe atmospheric "gusts" that might be encountered. The concern has resulted in a considerable body of high altitude gust acceleration data obtained with VGH recorders (airplane velocity, V, vertical acceleration, G, altitude, H) on high-flying airplanes like the U-2 (Ehernberger and Love, 1975). However, the propulsion system designer is less concerned with the accelerations of the airplane than he is with the airflow entering the system's inlet. When the airplane encounters atmospheric turbulence it responds with transient fluctuations in pitch, yaw, and roll angles. These transients, together with fluctuations in the free-stream temperature and pressure will disrupt the total pressure, temperature, Mach number and angularity of the inlet flow. For the mixed compression inlet, the result is a disturbed throat Mach number and/or shock position, and in extreme cases an inlet unstart can occur (cf. Section 2.1). Interest in the effects of inlet unstart on the vehicle dynamics of large, supersonic airplanes is not new. Results published by NASA in 1962 of wind tunnel studies of the problem were used in support of the United States Supersonic Transport program (SST) (White, at aI, 1963). Such studies continued into the late 1970's. However, in spite of such interest, there never was developed an atmospheric disturbance database for inlet unstart analysis to compare with that available for the structures load analysis. Missing were data for the free-stream temperature and pressure disturbances that also contribute to the unStart problem.

  16. Guidelines for predicting single-event upsets in neutron environments

    International Nuclear Information System (INIS)

    Single-event upsets (SEUs) in aerospace applications may generally be attributed to direct ionization by heavy nuclei in galactic cosmic radiation or to energetic recoils of substrate nuclei interacting with high-energy (E > 10 MeV) protons. In some aerospace applications the radiation environment is dominated by neutrons which are expected to be the principal cause of SEUs. These environments include the atmosphere at aircraft altitudes, in the vicinity of nuclear reactors and other neutron sources, nuclear weapons environments, and within heavily shielded spacecraft. Neutron-induced SEUs have been demonstrated in the laboratory and procedures for estimating error rates have been defined. In this paper utilizing the author's most recent computations of neutron burst generation rates, the authors introduce a simple, graphical technique for estimating neutron-induced error rates in various neutron environments

  17. The bibliometrics of atmospheric environment

    Science.gov (United States)

    Brimblecombe, Peter; Grossi, Carlota M.

    Bibliometric analysis is an important tool in the management of a journal. SCOPUS output is used to assess the increase in the quantity of material in Atmospheric Environment and stylistic changes in the way authors choose words and punctuation in titles and assemble their reference lists. Citation analysis is used to consider the impact factor of the journal, but perhaps more importantly the way in which it reflects the importance authors give to papers published in Atmospheric Environment. The impact factor of Atmospheric Environment (2.549 for 2007) from the Journal Citation Reports suggests it performs well within the atmospheric sciences, but it conceals the long term value authors place on papers appearing in the journal. Reference lists show that a fifth come through citing papers more than a decade old.

  18. Therapeutic potential of atmospheric neutrons

    OpenAIRE

    Voyant, Cyril; Roustit, Rudy; Tatje, Ifer; Biffi, Katia; Briancon, Jerome; Lantieri Marcovici, Celine

    2011-01-01

    Background Glioblastoma multiform (GBM) is the most common and most aggressive type of primary brain tumour in humans. It has a very poor prognosis despite multi-modality treatments consisting of open craniotomy with surgical resection, followed by chemotherapy and/or radiotherapy. Recently, a new treatment has been proposed – Boron Neutron Capture Therapy (BNCT) – which exploits the interaction between Boron-10 atoms (introduced by vector molecules) and low energy neutrons produced by giant ...

  19. Development of an operational neutron spectrometry system dedicated to the characterization of the natural atmospheric radiative environment, implemented at the Pic du Midi

    International Nuclear Information System (INIS)

    This PhD Thesis has been achieved thanks to the joint effort between two French organizations, the French Institute for Radiological Protection and Nuclear Safety (IRSN/LMDN, Cadarache) and the French Aerospace Lab (ONERA/ DESP, Toulouse). The aim was to develop an operational neutron spectrometer extended to high energies in order to measure the dynamics of the spectral variations of the natural radiative environment at the summit of the Pic du Midi Observatory in the French Pyrenees. Thereby, the fluence responses of each detector were calculated thanks to Monte Carlo simulations. Afterwards, they were validated by means of experimental campaigns up to high energies (≥20 MeV) nearby reference neutron fields. The systematic uncertainties were deduced after detailed studies of the mathematic reconstruction of the spectra (i.e. unfolding procedure). Then, the system was tested under rocks at the LSBB of Rustrel before being installed at respectively +500 m and +1000 m above sea level for the first environmental campaigns. Finally, the spectrometer has been operating for two years after its deployment at the summit of the Pic du Midi (+2885 m). The continuous data were analysed thanks to an innovative method. Some seasonal and spectral variations were observed. Some Forbush decreases were also recorded after strong solar flares. These data were further analysed thanks to Monte Carlo simulations. The data were made more attractive thanks to several practical applications with personnel dosimetry or reliability of submicron electronics components. (author)

  20. Single Event Effects: Space and Atmospheric Environments

    Science.gov (United States)

    Barth, Janet L.

    2003-01-01

    The paper discusses the following: 1. Sun-Earth connections. 2. Heavy ions: galactic cosmic rays; solar particle events. 3. Protons: solar particle events; trapped. 4. Atmospheric neutrons. 5. Summary.

  1. Neutrons from thunderstorms at low atmospheric altitudes and related doses at aircraft

    International Nuclear Information System (INIS)

    We conduct a simulation of thunderstorm neutron flashes at the lowest atmospheric altitudes below 10 km. The neutron generation mechanism is based on the nowadays conventional idea of possibility for photonuclear reactions to proceed on the atmospheric components owing to TGF photons. Our modeling includes generation of neutrons from TGF and their further propagation with account of interaction with background nuclei. Using the calculation results we investigate the neutron flux properties with respect to problem of their registration, and predict the radiation environment caused by thunderstorm neutrons on altitudes of civil airflights. It is shown, that good conditions for the neutron flashes observation are provided from the 3 km altitude, and, possibly, the neutrons can be registered at ground level. We also found that thunderstorm-neutron-related effective dose can reach the value of 0.5 mSv in the region close to the TGF source if it is located at an altitude of 10 km.

  2. Decrease of atmospheric neutron counts observed during thunderstorms.

    Science.gov (United States)

    Alekseenko, V; Arneodo, F; Bruno, G; Di Giovanni, A; Fulgione, W; Gromushkin, D; Shchegolev, O; Stenkin, Yu; Stepanov, V; Sulakov, V; Yashin, I

    2015-03-27

    We report here, in brief, some results of the observation and analysis of sporadic variations of atmospheric thermal neutron flux during thunderstorms. The results obtained with unshielded scintillation neutron detectors show a prominent flux decrease correlated with meteorological precipitations after a long dry period. No observations of neutron production during thunderstorms were reported during the three-year period of data recording. PMID:25860750

  3. Measuring the basic parameters of neutron stars using model atmospheres

    International Nuclear Information System (INIS)

    Model spectra of neutron star atmospheres are nowadays widely used to fit the observed thermal X-ray spectra of neutron stars. This fitting is the key element in the method of the neutron star radius determination. Here, we present the basic assumptions used for the neutron star atmosphere modeling as well as the main qualitative features of the stellar atmospheres leading to the deviations of the emergent model spectrum from blackbody. We describe the properties of two of our model atmosphere grids: i) pure carbon atmospheres for relatively cool neutron stars (1-4MK) and ii) hot atmospheres with Compton scattering taken into account. The results obtained by applying these grids to model the X-ray spectra of the central compact object in supernova remnant HESS 1731-347, and two X-ray bursting neutron stars in low-mass X-ray binaries, 4U 1724-307 and 4U 1608-52, are presented. Possible systematic uncertainties associated with the obtained neutron star radii are discussed. (orig.)

  4. Measuring the basic parameters of neutron stars using model atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Suleimanov, V.F. [Universitaet Tuebingen, Institut fuer Astronomie und Astrophysik, Kepler Center for Astro and Particle Physics, Tuebingen (Germany); Kazan Federal University, Kazan (Russian Federation); Poutanen, J. [University of Turku, Tuorla Observatory, Department of Physics and Astronomy, Piikkioe (Finland); KTH Royal Institute of Technology and Stockholm University, Nordita, Stockholm (Sweden); Klochkov, D.; Werner, K. [Universitaet Tuebingen, Institut fuer Astronomie und Astrophysik, Kepler Center for Astro and Particle Physics, Tuebingen (Germany)

    2016-02-15

    Model spectra of neutron star atmospheres are nowadays widely used to fit the observed thermal X-ray spectra of neutron stars. This fitting is the key element in the method of the neutron star radius determination. Here, we present the basic assumptions used for the neutron star atmosphere modeling as well as the main qualitative features of the stellar atmospheres leading to the deviations of the emergent model spectrum from blackbody. We describe the properties of two of our model atmosphere grids: i) pure carbon atmospheres for relatively cool neutron stars (1-4MK) and ii) hot atmospheres with Compton scattering taken into account. The results obtained by applying these grids to model the X-ray spectra of the central compact object in supernova remnant HESS 1731-347, and two X-ray bursting neutron stars in low-mass X-ray binaries, 4U 1724-307 and 4U 1608-52, are presented. Possible systematic uncertainties associated with the obtained neutron star radii are discussed. (orig.)

  5. Expression of Interest: The Atmospheric Neutrino Neutron Interaction Experiment (ANNIE)

    CERN Document Server

    Anghel, I; Bergevin, M; Davies, G; Di Lodovico, F; Elagin, A; Frisch, H; Hill, R; Jocher, G; Katori, T; Learned, J; Northrop, R; Pilcher, C; Ramberg, E; Sanchez, M C; Smy, M; Sobel, H; Svoboda, R; Usman, S; Vagins, M; Varner, G; Wagner, R; Wetstein, M; Winslow, L; Yeh, M

    2014-01-01

    Neutron tagging in Gadolinium-doped water may play a significant role in reducing backgrounds from atmospheric neutrinos in next generation proton-decay searches using megaton-scale Water Cherenkov detectors. Similar techniques might also be useful in the detection of supernova neutrinos. Accurate determination of neutron tagging efficiencies will require a detailed understanding of the number of neutrons produced by neutrino interactions in water as a function of momentum transferred. We propose the Atmospheric Neutrino Neutron Interaction Experiment (ANNIE), designed to measure the neutron yield of atmospheric neutrino interactions in gadolinium-doped water. An innovative aspect of the ANNIE design is the use of precision timing to localize interaction vertices in the small fiducial volume of the detector. We propose to achieve this by using early production of LAPPDs (Large Area Picosecond Photodetectors). This experiment will be a first application of these devices demonstrating their feasibility for Wate...

  6. Letter of Intent: The Atmospheric Neutrino Neutron Interaction Experiment (ANNIE)

    CERN Document Server

    Anghel, I; Bergevin, M; Blanco, C; Catano-Mur, E; Di Lodovico, F; Elagin, A; Frisch, H; Griskevich, J; Hill, R; Jocher, G; Katori, T; Krennrich, F; Learned, J; Malek, M; Northrop, R; Pilcher, C; Ramberg, E; Repond, J; Sacco, R; Sanchez, M C; Smy, M; Sobel, H; Svoboda, R; Usman, S M; Vagins, M; Varner, G; Wagner, R; Weinstein, A; Wetstein, M; Winslow, L; Xia, L; Yeh, M

    2015-01-01

    Neutron tagging in Gadolinium-doped water may play a significant role in reducing backgrounds from atmospheric neutrinos in next generation proton-decay searches using megaton-scale Water Cherenkov detectors. Similar techniques might also be useful in the detection of supernova neutrinos. Accurate determination of neutron tagging efficiencies will require a detailed understanding of the number of neutrons produced by neutrino interactions in water as a function of momentum transferred. We propose the Atmospheric Neutrino Neutron Interaction Experiment (ANNIE), designed to measure the neutron yield of atmospheric neutrino interactions in gadolinium-doped water. An innovative aspect of the ANNIE design is the use of precision timing to localize interaction vertices in the small fiducial volume of the detector. We propose to achieve this by using early production of LAPPDs (Large Area Picosecond Photodetectors). This experiment will be a first application of these devices demonstrating their feasibility for Wate...

  7. Measuring the basic parameters of neutron stars using model atmospheres

    CERN Document Server

    Suleimanov, V F; Klochkov, D; Werner, K

    2015-01-01

    Model spectra of neutron star atmospheres are nowadays widely used to fit the observed thermal X-ray spectra of neutron stars. This fitting is the key element in the method of the neutronstar radius determination. Here, we present the basic assumptions used for the neutron star atmosphere modeling as well as the main qualitative features of the stellar atmospheres leading to the deviations of the emergent model spectrum from blackbody. We describe the properties of two of our model atmosphere grids: (i) pure carbon atmospheres for relatively cool neutron stars (1--4 MK) and (ii) hot atmospheres with Compton scattering taken into account. The results obtained by applying these grids to model the X-ray spectra of the central compact object in supernova remnant HESS 1731-347, and two X-ray bursting neutron stars in low-mass X-ray binaries, 4U 1724-307 and 4U 1608-52, are presented. Possible systematic uncertainties associated with the obtained neutron star radii are discussed.

  8. Space, Atmospheric, and Terrestrial Radiation Environments

    Science.gov (United States)

    Barth, Janet L.; Dyer, C. S.; Stassinopoulos, E. G.

    2003-01-01

    The progress on developing models of the radiation environment since the 1960s is reviewed with emphasis on models that can be applied to predicting the performance of microelectronics used in spacecraft and instruments. Space, atmospheric, and ground environments are included. It is shown that models must be adapted continually to account for increased understanding of the dynamics of the radiation environment and the changes in microelectronics technology. The IEEE Nuclear and Space Radiation Effects Conference is a vital forum to report model progress to the radiation effects research community.

  9. The Radiation Environment of Exoplanet Atmospheres

    Directory of Open Access Journals (Sweden)

    Jeffrey L. Linsky

    2014-10-01

    Full Text Available Exoplanets are born and evolve in the radiation and particle environment created by their host star. The host star’s optical and infrared radiation heats the exoplanet’s lower atmosphere and surface, while the ultraviolet, extreme ultraviolet and X-radiation control the photochemistry and mass loss from the exoplanet’s upper atmosphere. Stellar radiation, especially at the shorter wavelengths, changes dramatically as a host star evolves leading to changes in the planet’s atmosphere and habitability. This paper reviews the present state of our knowledge concerning the time-dependent radiation emitted by stars with convective zones, that is stars with spectral types F, G, K, and M, which comprise nearly all of the host stars of detected exoplanets.

  10. Radiation environment models and the atmospheric cutoff

    Science.gov (United States)

    Konradi, Andrei; Hardy, Alva C.; Atwell, William

    1987-01-01

    The limitations of radiation environment models are examined by applying the model to the South Atlantic anomaly (SAA). The local magnetic-field-intensity (in gauss) and McIlwain (1961) drift-shell-parameter contours in the SAA are analyzed. It is noted that it is necessary to decouple the atmospheric absorption effects from the trapped radiation models in order to obtain accurate radiation dose predictions. Two methods for obtaining more accurate results are proposed.

  11. White dwarf atmospheres and circumstellar environments

    CERN Document Server

    Hoard, Donald W

    2012-01-01

    Written by selected astronomers at the forefront of their fields, this timely and novel book compiles the latest results from research on white dwarf stars, complementing existing literature by focusing on fascinating new developments in our understanding of the atmospheric and circumstellar environments of these stellar remnants. Complete with a thorough refresher on the observational characteristics and physical basis for white dwarf classification, this is a must-have resource for researchers interested in the late stages of stellar evolution, circumstellar dust and nebulae, and the future

  12. Levitating atmospheres of Eddington-luminosity neutron stars

    Science.gov (United States)

    Wielgus, Maciek; Sądowski, Aleksander; Kluźniak, Włodek; Abramowicz, Marek; Narayan, Ramesh

    2016-06-01

    We construct models of static, spherically symmetric shells supported by the radiation flux of a luminous neutron star in the Schwarzschild metric. The atmospheres are disconnected from the star and levitate above its surface. Gas pressure and density inversion appear in the inner region of these atmospheres, which is a purely relativistic phenomenon. We account for the scattering opacity dependence on temperature green by using the Klein-Nishina formula. The relativistic M1 closure scheme for the radiation tensor provides a general relativity-consistent treatment of the photon flux and radiation tensor anisotropy. In this way, we are able to address atmospheres of both large and moderate/low optical depths with the same set of equations. We discuss properties of the levitating atmospheres and find that they may indeed be optically thick, with the distance between star surface and the photosphere expanding as luminosity increases. These results may be relevant for the photosphereric radius expansion X-ray bursts.

  13. Levitating atmospheres of Eddington-luminosity neutron stars

    CERN Document Server

    Wielgus, Maciek; Kluzniak, Wlodek; Abramowicz, Marek; Narayan, Ramesh

    2015-01-01

    We construct models of static, spherically symmetric shells supported by the radiation flux of a luminous neutron star in the Schwarzschild metric. The atmospheres are disconnected from the star and levitate above its surface. Gas pressure and density inversion appear in the inner region of these atmospheres, which is a purely relativistic phenomenon. We account for the scattering opacity dependence on temperature and utilize the relativistic M1 closure scheme for the radiation tensor, hence allowing for a fully GR-consistent treatment of the photon flux and radiation tensor anisotropy. In this way we are able to address atmospheres of both large and moderate/low optical depths with the same set of equations. We discuss properties of the levitating atmospheres and find that they may indeed be optically thick, with the distance between star surface and the photosphere expanding as luminosity increases. These results may be relevant for the photosphereric radius expansion X-ray bursts.

  14. Neutron spectrometry and dosimetry in the environment and at workplaces

    International Nuclear Information System (INIS)

    Results obtained in diverse environments (including workplaces) using both spectrometric and dosimetric instrumentation were compared. The following topics are included: PTB Bonner sphere spectrometers; natural cosmic ray-induced neutron background; neutron fields at the Dukovany nuclear power plant (Czech Republic); neutron fields at the isochronous cyclotron of the German Cancer Research center in Heidelberg; and accuracy of the integral results obtained with Bonner spheres. (P.A.)

  15. Object-oriented data analysis environment for neutron scattering

    International Nuclear Information System (INIS)

    A systematic approach based on the object-oriented methodology was taken to develop a software framework, in which users could easily develop and execute their analysis software in the neutron-scattering experiments. The framework has common and generic analysis functionalities for the neutron-scattering experiments. The first version was applied to the analysis of a real experimental data and was found to be a convenient environment for setting up and running data analysis software for the neutron-scattering instruments

  16. Updated neutron spectrum characterization of SNL baseline reactor environments

    International Nuclear Information System (INIS)

    The neutron spectrum characteristics of the primary reactor environments are defined for use by facility customers and to provide an audit trail in support of current quality assurance initiatives. The neutron and gamma environments in the four primary customer environments at SPR-III and ACRR facilities are characterized in detail. Enough detail is provided on other frequently-used environments to support the definition of the 3-MeV and 1-MeV(Si) fluence provided on the Radiation Metrology Laboratory dosimetry reports

  17. Atmospheres of Quiescent Low-Mass Neutron Stars

    Science.gov (United States)

    Karpov, Platon; Medin, Zachary; Calder, Alan; Lattimer, James M.

    2016-01-01

    Observations of the neutron stars in quiescent low-mass X-ray binaries are important for determining their masses and radii which can lead to powerful constraints on the dense matter nuclear equation of state. The interpretation of these sources is complex and their spectra differ appreciably from blackbodies. Further progress hinges on reducing the uncertainties stemming from models of neutron star atmospheres. We present a suite of low-temperature neutron star atmospheres of different chemical compositions (pure H and He). Our models are constructed over a range of temperatures [log(T/1 K)=5.3, 5.6, 5.9, 6.2, 6.5] and surface gravities [log(g/1 cm/s2)=14.0, 14.2, 14.4, 14.6]. We generated model atmospheres using zcode - a radiation transfer code developed at Los Alamos National Laboratory. In order to facilitate analytic studies, we developed three-parameter fits to our models, and also compared them to diluted blackbodies in the energy range of 0.4-5 keV (CXO/MGE). From the latter, we extract color-correction factors (fc), which represent the shift of the spectra as compared to a blackbody with the same effective temperature. These diluted blackbodies are also useful for studies of photspheric expansion X-ray bursts. We provide a comparison of our models to previous calculations using the McGill Planar Hydrogen Atmosphere Code (McPHAC). These results enhance our ability to interpret thermal emission from neutron stars and to constrain the mass-radius relationship of these exotic objects.This research was supported in part by the U.S. Department of Energy under grant DE-FG02-87ER40317 and by resources at the Institute for Advanced Computational Science at Stony Brook University. This research was carried out in part under the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory and supported by Contract No. DE-AC52-06NA25396.

  18. The changing winds of atmospheric environment policy

    International Nuclear Information System (INIS)

    Highlights: ► Changes in atmosphere policies over several decades are analysed. ► Direct regulation is less effective and been complemented by other instruments. ► Policy approaches are more complex and integrated and the scale of the issues has evolved. ► The role of stakeholders has grown and the corporate sector has assumed increased responsibility. ► Governance arrangements have become more complex, multilevel and polycentric. -- Abstract: Atmospheric environmental policies have changed considerably over the last several decades. Clearly the relative importance of the various issues has changed over half a century, for example from smoke, sulphur dioxide and photochemical smog being the top priorities to greenhouse gases being the major priority. The traditional policy instrument to control emissions to the atmosphere has been command and control regulation. In many countries this was successful in reducing emissions from point sources, the first generation issues, and to a lesser extent, emissions from mobile and area sources, the second generation issues, although challenges remain in many jurisdictions. However once the simpler, easier, cheaper and obvious targets had been at least partially controlled this form of regulation became less effective. It has been complemented by other instruments including economic instruments, self-regulation, voluntarism and information instruments to address more complex issues including climate change, a third generation issue. Policy approaches to atmospheric environmental issues have become more complex. Policies that directly focus on atmospheric issues have been partially replaced by more integrated approaches that consider multimedia (water, land, etc.) and sustainability issues. Pressures from stakeholders for inclusion, greater transparency and better communication have grown and non-government stakeholders have become increasingly important participants in governance. The scale of the issues has evolved

  19. Atmospheric environment for ASTP (SA-210) launch

    Science.gov (United States)

    Johnson, D. L.

    1976-01-01

    A summary is presented of selected atmospheric conditions observed near ASTP/SA-210 launch time on July 15, 1975, at Kennedy Space Center, Florida. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), density, index of refraction, and wind/wind shear aloft are included. A final meteorological data tape for the ASTP launch, consisting of wind and thermodynamic parameters versus altitude, has been constructed.

  20. Harsh Environment Gas Sensor Array for Venus Atmospheric Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering and the Ohio State University propose to develop a harsh environment tolerant gas sensor array for atmospheric analysis in future Venus missions....

  1. The host galaxy and environment of a neutron star merger

    CERN Document Server

    Postigo, A de Ugarte; Rowlinson, A; Garcia-Benito, R; Levan, A J; Gorosabel, J; Goldoni, P; Schulze, S; Zafar, T; Wiersema, K; Sanchez-Ramirez, R; Melandri, A; D'Avanzo, P; Oates, S; D'Elia, V; De Pasquale, M; Kruehler, T; van der Horst, A J; Xu, D; Watson, D; Piranomonte, S; Vergani, S; Milvang-Jensen, B; Kaper, L; Malesani, D; Fynbo, J P U; Cano, Z; Covino, S; Flores, H; Greiss, S; Hammer, F; Hartoog, O E; Hellmich, S; Heuser, C; Hjorth, J; Jakobsson, P; Mottola, S; Sparre, M; Sollerman, J; Tagliaferri, G; Tanvir, N R; Vestergaard, M; Wijers, R A M J

    2013-01-01

    The mergers of neutron stars have been predicted to cause an r-process supernova - a luminous near-infrared transient powered by the radioactive decay of freshly formed heavy metals. An r-process supernova, or kilonova, has recently been discovered coincident with the short-duration gamma-ray burst GRB 130603B, simultaneously confirming the widely-held theory of the origin of most short-durations GRBs in neutron star mergers. We report here the absorption spectrum of the afterglow of this GRB. From it we determine the redshift of the burst and the properties of the host galaxy and the environment in which the merger occurred. The merger is not associated with the most star-forming region of the galaxy; however, it did occur in a dense region, implying a rapid merger or a low natal kick velocity for the neutron star binary.

  2. Measurement of atmospheric neutron and photon energy spectra at aviation altitudes using a phoswich-type neutron detector

    International Nuclear Information System (INIS)

    Neutron energy spectrum from 7 to 180 MeV and photon energy spectrum from 4 to 50 MeV were measured onboard an aircraft using a newly developed phoswich-type neutron detector at 10.8 km altitude (atmospheric depth of 249 g/cm2) and geographical latitude of 39degN (a vertical cut-off rigidity of 10.2 GV) near Japan on February 13, 2008 (at a heliocentric potential of 312 MV). Our results were compared with other measurements obtained using 3He-loaded or extended-energy multi moderator neutron spectrometers (Bonner balls) at aviation altitudes, an organic liquid scintillator on the ground, and a double-scatter neutron telescope at the top of the atmosphere and with calculations using the LUIN2000, EXPACS and RMC codes. Our measured results give a large, sharp peak around a neutron energy of 70 MeV, although Bonner balls present a broad peak around 100 MeV due to low energy resolution. Our neutron fluxes agree well with the others. The measured photon energy spectrum is between the LUIN2000- and EXPACS-calculated spectra and agrees with measured vertical photon spectra at the top of the atmosphere. This onboard study provides the first experimental neutron energy spectrum in the high-energy region (over 10 MeV) with a high energy resolution. (author)

  3. 1988 activity report of the Atmospheric and Aquatic Environment Department

    International Nuclear Information System (INIS)

    The 1988 activity report of the Atmospheric and Aquatic Environment Department of EDF (Electricity of France) is presented. The activities are focused on the following subjects: development studies in the fields of hydraulic, hydrobiology, meteorology and atmospheric polluants physico-chemistry; application studies involving data analysis from operating or under development power systems; actions concerning cooperation with the Minister of the Environment and the Minister of the Industry. The investigations related to water and atmosphere are reported, as well as congress communications and papers

  4. Atmospheric Environments for Entry, Descent and Landing (EDL)

    Science.gov (United States)

    Justus, Carl G.; Braun, Robert D.

    2007-01-01

    Scientific measurements of atmospheric properties have been made by a wide variety of planetary flyby missions, orbiters, and landers. Although landers can make in-situ observations of near-surface atmospheric conditions (and can collect atmospheric data during their entry phase), the vast majority of data on planetary atmospheres has been collected by remote sensing techniques from flyby and orbiter spacecraft (and to some extent by Earth-based remote sensing). Many of these remote sensing observations (made over a variety of spectral ranges), consist of vertical profiles of atmospheric temperature as a function of atmospheric pressure level. While these measurements are of great interest to atmospheric scientists and modelers of planetary atmospheres, the primary interest for engineers designing entry descent and landing (EDL) systems is information about atmospheric density as a function of geometric altitude. Fortunately, as described in in this paper, it is possible to use a combination of the gas-law relation and the hydrostatic balance relation to convert temperature-versus-pressure, scientific observations into density-versus-altitude data for use in engineering applications. The following section provides a brief introduction to atmospheric thermodynamics, as well as constituents, and winds for EDL. It also gives methodology for using atmospheric information to do "back-of-the-envelope" calculations of various EDL aeroheating parameters, including peak deceleration rate ("g-load"), peak convective heat rate. and total heat load on EDL spacecraft thermal protection systems. Brief information is also provided about atmospheric variations and perturbations for EDL guidance and control issues, and atmospheric issues for EDL parachute systems. Subsequent sections give details of the atmospheric environments for five destinations for possible EDL missions: Venus. Earth. Mars, Saturn, and Titan. Specific atmospheric information is provided for these destinations

  5. Models of neutron star atmospheres enriched with nuclear burning ashes

    CERN Document Server

    Nättilä, Joonas; Kajava, Jari J E; Poutanen, Juri

    2015-01-01

    Low-mass X-ray binaries hosting neutron stars (NS) exhibit thermonuclear (type-I) X-ray bursts, which are powered by unstable nuclear burning of helium and/or hydrogen into heavier elements deep in the NS "ocean". In some cases the burning ashes may rise from the burning depths up to the NS photosphere by convection, leading to the appearance of the metal absorption edges in the spectra, which then force the emergent X-ray burst spectra to shift toward lower energies. These effects may have a substantial impact on the color correction factor $f_c$ and the dilution factor $w$, the parameters of the diluted blackbody model $F_E \\approx w B_E(f_c T_{eff})$ that is commonly used to describe the emergent spectra from NSs. The aim of this paper is to quantify how much the metal enrichment can change these factors. We have developed a new NS atmosphere modeling code, which has a few important improvements compared to our previous code required by inclusion of the metals. The opacities and the internal partition func...

  6. Measurement result of the neutron monitor onboard the Space Environment Data Acquisition Equipment - Attached Payload (SEDA-AP)

    Science.gov (United States)

    Koga, K.; Muraki, Y.; Shibata, S.; Yamamoto, T.; Matsumoto, H.; Okudaira, O.; Kawano, H.; Yumoto, K.

    2013-12-01

    To support future space activities, it is crucial to acquire space environmental data related to the space-radiation degradation of space parts and materials, and spacecraft anomalies. Such data are useful for spacecraft design and manned space activity. SEDA-AP was mounted on 'Kibo' of the ISS (International Space Station) to measure the space environment at a 400-kilometer altitude. Neutrons are very harmful radiation, with electrical neutrality that makes them strongly permeable. SEDA-AP measures the energy of neutrons from thermal to 100 MeV in real time using a Bonner Ball Detector (BBND) and a Scintillation Fiber Detector (FIB). BBND detects neutrons using He-3 counters, which have high sensitivity to thermal neutrons. Neutron energy is derived using the relative response function of polyethylene moderators of 6 different thicknesses. FIB measures the tracks of recoil protons caused by neutrons within a cubic arrayed sensor of 512 scintillation fibers. The charged particles are excluded using an anti-scintillator which surrounds the cube sensor, and the neutron energy is obtained from the track length of a recoil proton. There are three sources of neutrons in space; 1. Albedo Neutrons Produced by reactions of galactic cosmic rays or radiation belt particles with the atmosphere 2. Local Neutrons Produced by the reactions of galactic cosmic rays or radiation belt particles with spacecraft 3. Solar Neutrons Produced by accelerated particles in solar flares An accurate energy spectrum of the solar neutrons includes important information on high-energy particle generation mechanism in a solar flare, because neutrons are unaffected by interplanetary magnetic fields. These data will become useful to forecast solar energetic particles in future. Some candidate events involving solar neutrons were found as a result of analyzing data of the solar flare of M>2 since September 2009. Moreover, it is important to measure albedo neutrons, since protons generated by neutron

  7. The heating environment during Martian atmospheric descent

    Science.gov (United States)

    Tauber, Michael E.; Yang, Lily

    1988-01-01

    It has been shown that a vehicle with a lift/drag ratio of 2.3 entering the Martian atmosphere at parabolic speed of 5 km/sec, or from a low orbit at 3.5 km/sec, has a very large landing footprint. At the 5-km/sec entry speed, the trajectory exhibits large skipping motions; however, a lateral range of up to 3300 km is attainable. The entries from low satellite orbit yield a gliding lateral range of 2500 km. The distances correspond to latitude changes of 57 and 42 deg, respectively. The high-speed, skipping entries were accompanied by the most intense heating. The peak stagnation point convective rates varied from 59 W/sq cm to 88 W/sq cm for partially and fully catalytic walls, respectively; the corresponding equilibrium wall temperatures were 1900 K and 2100 K. The peak heating at a wing leading-edge point reached 50 W/sq cm because of the presence of a transitional boundary layer. The lower-speed, gliding entries experienced much milder heating with a peak stagnation point rate of about 14 W/sq cm, resulting in a wall temperature near 1300 K. However, the longer duration of the gliding entries resulted in comparable heat loads for both entry speeds. The highest heat loads approached values experienced by the Shuttle orbiter stagnation point during a typical entry.

  8. Altitude and latitude variations in avionics SEU and atmospheric neutron flux

    International Nuclear Information System (INIS)

    The direct cause of single event upsets in SRAMs at aircraft altitudes by the atmospheric neutrons has previously been documented. The variation of the in-flight SEU rate with latitude is demonstrated by new data over a wide range of geographical locations. New measurements and models of the atmospheric neutron flux are also evaluated to characterize its variation with altitude, latitude and solar activity

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

    Science.gov (United States)

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

    2010-01-01

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

  10. Characteristics of the aerosol particulates in the atmosphere in an urban environment at Faisalabad, Pakistan

    International Nuclear Information System (INIS)

    The deposition of trace and major elements from the atmosphere to the ground is an important factor for plants, animals and humans as well. Total suspended particulate matter was measured by a standard gravimetric technique. A scanning electron microscope was used for the evaluation of the size distribution and morphological structures of the aerosol particulates trapped on the surface of filter paper. The aerosol particulates were studied by a scanning electron microscope at various magnification. The trace elemental composition in the atmosphere of Faisalabad was studied by using instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). Concentrations of 23 trace elements and a major one were determined in samples of aerosol particulates collected during a longe sampling period in the atmosphere at Faisalabad, Pakistan. Their amount was two times higher than the limits adopted by the U.S. Environmental Protection Agency for the urban environment. (author)

  11. A Balloon-borne Measurement of High Latitude Atmospheric Neutrons Using a LiCAF Neutron Detector

    CERN Document Server

    Kole, Merlin; Fukuda, Kentaro; Ishizu, Sumito; Jackson, Miranda; Kamae, Tune; Kawaguchi, Noriaki; Kawano, Takafumi; Kiss, Mózsi; Moretti, Elena; Salinas, Maria Fernanda Muñoz; Pearce, Mark; Rydström, Stefan; Takahashi, Hiromitsu; Yanagida, Takayuki

    2013-01-01

    PoGOLino is a scintillator-based neutron detector. Its main purpose is to provide data on the neutron flux in the upper stratosphere at high latitudes at thermal and nonthermal energies for the PoGOLite instrument. PoGOLite is a balloon borne hard X-ray polarimeter for which the main source of background stems from high energy neutrons. No measurements of the neutron environment for the planned flight latitude and altitude exist. Furthermore this neutron environment changes with altitude, latitude and solar activity, three variables that will vary throughout the PoGOLite flight. PoGOLino was developed to study the neutron environment and the influences from these three variables upon it. PoGOLino consists of two Europium doped Lithium Calcium Aluminium Fluoride (Eu:LiCAF) scintillators, each of which is sandwiched between 2 Bismuth Germanium Oxide (BGO) scintillating crystals, which serve to veto signals produced by gamma-rays and charged particles. This allows the neutron flux to be measured even in high rad...

  12. Aviation Safety Program Atmospheric Environment Safety Technologies (AEST) Project

    Science.gov (United States)

    Colantonio, Ron

    2011-01-01

    Engine Icing: Characterization and Simulation Capability: Develop knowledge bases, analysis methods, and simulation tools needed to address the problem of engine icing; in particular, ice-crystal icing Airframe Icing Simulation and Engineering Tool Capability: Develop and demonstrate 3-D capability to simulate and model airframe ice accretion and related aerodynamic performance degradation for current and future aircraft configurations in an expanded icing environment that includes freezing drizzle/rain Atmospheric Hazard Sensing and Mitigation Technology Capability: Improve and expand remote sensing and mitigation of hazardous atmospheric environments and phenomena

  13. Atmospheres and radiating surfaces of neutron stars with strong magnetic fields

    CERN Document Server

    Potekhin, A Y; Chabrier, G

    2016-01-01

    We review the current status of the theory of thermal emission from the surface layers of neutron stars with strong magnetic fields $B\\sim 10^{10}-10^{15}$ G, including formation of the spectrum in a partially ionized atmosphere and at a condensed surface. In particular, we describe recent progress in modeling partially ionized atmospheres of central compact objects in supernova remnants, which may have moderately strong fields $B\\sim 10^{10}-10^{11}$ G. Special attention is given to polarization of thermal radiation emitted by a neutron star surface. Finally, we briefly describe applications of the theory to observations of thermally emitting isolated neutron stars.

  14. Impact of atmospheric 14C to the karst environment

    International Nuclear Information System (INIS)

    Naturally cosmic-ray produced radiocarbon 14C is a part of the CO2 cycle and through the atmosphere-biosphere-hydrosphere exchange process it has been introduced to the environment. Anthropogenic disturbance of the natural 14C activity caused by nuclear tests, nuclear power plants and also by fossil fuel combustion has been recorded in the atmospheric CO2. The karst environment including water, carbonate sediment and soil, where exchange processes within the CO2-HCO3 -CaCO3 system play an important role, is very sensitive to any change in the atmosphere and response to the contamination is very fast. 14C activity of atmospheric CO2 has been continuously measured in monthly samples in Zagreb area since 1983. Seasonal variations have been observed, as well as steady decrease of yearly mean values. Influence of fossil fuel combustion in the city area during winter months was also observed. Few examples of isotopic study in karst environment in Croatia and Slovenia will be presented: 1) The influence of atmospheric 14C activity to the recent carbonate precipitated in the surface water in form of tufa in the Plitvice Lakes, Korana, Krka and Zrmanja rivers in Croatia, and Krka river in Slovenia; 2) 14C activity in recent speleothems from several caves in Croatia and Postojna Cave in Slovenia; 3) Distribution of 14C activity in the surface soil in Plitvice Lakes and Postojna areas; 4) 14C activity of atmospheric CO2 inside and outside the Postojna Cave, 5) 14C activity in recent plants (aquatic and terrestrial) and shells. The stable isotopes δ 13C and δ 18O for some of the samples above will be presented too. Distribution of 14C in the karst environment will be discussed and compared with 14C activity of atmospheric CO2

  15. Measurement and simulation of the radiation environment in the lower atmosphere for dose assessment

    International Nuclear Information System (INIS)

    Flying personnel is occupationally exposed to rather high radiation levels due to secondary cosmic radiation. Therefore, the radiation environment induced in the lower atmosphere by galactic and solar cosmic radiation was characterized by means of particle transport calculations using GEANT4. These calculations were validated with continuous measurements of the energy spectra of secondary neutrons with Bonner sphere spectrometers at the Zugspitze mountain and near the North Pole. The response of these instruments was determined with GEANT4 and for the first time experimentally verified at high neutron energies (244 and 387 MeV). Route doses for aircrews along typical long-haul flights were determined for galactic and solar cosmic radiation using most recent data on the magnetospheric field and primary cosmic radiation.

  16. Electron assisted neutron exchange process in solid state environment

    CERN Document Server

    Kálmán, Péter

    2013-01-01

    Electron assisted neutron exchange process in solid state environment is investigated. It is shown that if a metal is irradiated with free electrons then the $e+$ $_{Z}^{A_{1}}X+$ $_{Z}^{A_{2}}X\\rightarrow e^{\\prime }+$ $% _{Z}^{A_{1}-1}X+$ $_{Z}^{A_{2}+1}X+\\Delta $ electron assisted neutron exchange process has measurable probability even in the case of slow electrons of energy much less than the reaction energy $\\Delta $. The transition probability per unit time, the cross section of the process and the yield in an irradiated sample are determined in the Weisskopf and long wavelength approximations and in the single particle shell model. Numerical data for the $e+$ $_{28}^{A_{1}}Ni+$ $_{28}^{A_{2}}Ni\\rightarrow e^{\\prime }+ $ $_{28}^{A_{1}+1}Ni+$ $_{28}^{A_{2}-1}Ni+\\Delta $ and the $e+$ $% _{46}^{A_{1}}Pd+$ $_{46}^{A_{2}}Pd\\rightarrow e^{\\prime }+$ $% _{46}^{A_{1}+1}Pd+$ $_{46}^{A_{2}-1}Pd+\\Delta $ electron assisted neutron exchange reactions are also presented.

  17. Atmospheric environment responses to fossil energy and renewable energy alternatives

    International Nuclear Information System (INIS)

    Fossil energy consumption and the atmospheric environmental problems are closely related leading together with various recent weather phenomena such as the climate change, global warming, greenhouse effect and atmospheric pollution. Accumulation of harmful emissions from the fossil fuels such as coal and oil causes increase in carbon dioxide levels in the atmosphere which shield the long wave solar irradiation from the earth to outer space and consequently the temperature within the atmospheric layer increases giving rise to expected global warming and many long term undesirable disastrous events such as droughts, floods, the sea level rises as a result of polar ice melting, shifts of tropical belts towards the polar regions, undulating of low lying lands in addition to many other social effects. In order to reduce these undesirable effects, the atmosphere as a common property of all the world, must be protected jointly by all the countries. Hence, each country must contribute her share by reducing the use of fossil fuels with the replacement of environment friendly renewable energy resources such as solar, solar-hydrogen, wind and hydropower. In order to know the right for a country to defend herself for future accusations of atmospheric environmental pollution she must know and set up policies as her energy consumption levels and renewable energy potentials. This paper presents general account of fossil fuel usage consequences in the atmosphere. 15 refs

  18. Assessment of the effects of atmospheric neutrons on onboard electronic equipment and search for hardening solutions

    International Nuclear Information System (INIS)

    This work deals with the impact of atmospheric neutrons on complex electronic components such as built-in memories or processors. The first part describes the radiation environment, the neutron-matter interaction and the consequences on electronic devices, and presents the commonly used experimental simulations and the testing methods. The potential of laser beam for testing is highlighted. The second chapter presents the development of a testing platform for various types of memories (MRAM and SDRAM). The equipment and the dedicated software are described. A testing platform for processor is also presented. The third chapter is dedicated to the presentation of a 4 Mbit bulk-type SRAM memory and of its testing involving a laser beam equipment. Several results show the presence of error clusters that may endangered the memory as a whole. These error clusters are due to the architecture of the internal addressing scheme of the memory. The simulation of these error clusters must be improved in order to define an optimized strategy of hardening

  19. Large eddy simulation of city micro-atmospheric environment

    Institute of Scientific and Technical Information of China (English)

    CUI GuiXiang; SHI RuiFeng; WANG ZhiShi; XU ChunXiao; ZHANG ZhaoShun

    2008-01-01

    Air quality is one of the important conditions for a better residence life in the populated urban area and it is closed related to the micro-atmospheric environment.Atmospheric environment is controlled by air motion with multi-scales in the city,while air flows in the residence area are of micro-scale atmospheric motion. This paper introduces a modern numerical simulation method, i.e. large eddy simulation (LES), for studying micro-atmospheric flows in the city residence area. For the complex flow features in the residence area, the proper application of LES is stud-ied and various numerical methods are compared in order to investigate their ef-fects on the prediction accuracy of micro-atmospheric flows, for instance, rough-ness elements and immersed boundary method for complex terrain, different sub-grid models and so on. The wind field (including turbulence properties) and con-taminant dispersion are computed by the proposed method for a model and a re-alistic residence area, and the numerical results are in good agreement with the experimental measurements.

  20. Large eddy simulation of city micro-atmospheric environment

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Air quality is one of the important conditions for a better residence life in the populated urban area and it is closed related to the micro-atmospheric environment. Atmospheric environment is controlled by air motion with multi-scales in the city,while air flows in the residence area are of micro-scale atmospheric motion. This paper introduces a modern numerical simulation method,i.e. large eddy simulation(LES) ,for studying micro-atmospheric flows in the city residence area. For the complex flow features in the residence area,the proper application of LES is studied and various numerical methods are compared in order to investigate their effects on the prediction accuracy of micro-atmospheric flows,for instance,roughness elements and immersed boundary method for complex terrain,different subgrid models and so on. The wind field(including turbulence properties) and contaminant dispersion are computed by the proposed method for a model and a realistic residence area,and the numerical results are in good agreement with the experimental measurements.

  1. Atmospheric environment for Space Shuttle Atlantis (STS-43) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1992-01-01

    A summary of selected atmospheric conditions observed near Space Shuttle Atlantis (STS-43) launch time on August 2, 1991, at Kennedy Space Center, Florida is presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is given. The final atmospheric profile, which consists of wind and thermodynamic parameters versus altitude, for STS-43 vehicle ascent was constructed. The STS-43 ascent atmospheric data profile was constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consisted data set for use in postflight performance assessments and represents the best estimate of the launch environment to the 400,000-ft altitude that was traversed by the STS-43 vehicle.

  2. Atmospheric environment for space shuttle (STS-35) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1991-01-01

    A summary is given of selected atmospheric conditions observed near space shuttle STS-35 launch time on December 2, 1990, at Kennedy Space Center, Florida. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is given in this report. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-35 vehicle ascent has been constructed. The STS-35 ascent atmospheric data tape has been constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in postflight performance assessments and represents the best estimate of the launch environment to the 400,000-ft altitude that was traversed by the STS-35 vehicle.

  3. Atmospheric environment for Space Shuttle (STS-37) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1991-01-01

    A summary of selected atmospheric conditions observed near Space Shuttle STS-37 launch time on 5 Apr. 1991 at KSC is presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (clouds), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-37 vehicle ascent was constructed. The STS-37 ascent atmospheric data tape was constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in postflight performance assessments and represents the best estimate of the launch environment to the 400,000 ft. altitude that was traversed by the STS-37 vehicle.

  4. Atmospheric environment for space shuttle (STS-41) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1990-01-01

    A summary of selected atmospheric conditions observed near space shuttle STS-41 launch time on October 6, 1990, at Kennedy Space Center, Florida are presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (clouds), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-41 vehicle ascent was constructed. The STS-41 ascent atmospheric data tape was constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in postflight performance assessments and represents the best estimate of the launch environment to the 400,000 ft altitude that was traversed by the STS-41 vehicle.

  5. Atmospheric environment for Space Shuttle Columbia (STS-40) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1992-01-01

    A summary of selected atmospheric conditions observed near the Space Shuttle Columbia (STS-40) launch time on 5 Jun. 1991, at KSC is presented. Values of ambient pressure, temperature, moisture, ground winds, visual observation (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-40 vehicle ascent was constructed. The STS-40 ascent atmospheric data tape was constructed by MSFC's Earth Science and Applications Division to provide an internally consistent data set for use in postflight performance assessments and represents the best estimate of the launch environment to the 400,000-ft altitude that was traversed by the STS-40 vehicle.

  6. Atmospheric environment for space shuttle (STS-38) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1991-01-01

    A summary of selected atmospheric conditions observed near space shuttle STS-38 launch time on November 15, 1990, at Kennedy Space Center is presented. STS-38 carried a Department of Defense payload and the flight azimuth in this report will be denoted by a reference flight azimuth, since the actual flight azimuth is not known. Values of ambient pressure, temperature, moisture, ground winds, visual observation (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is presented. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-38 vehicle ascent was constructed. The STS-38 ascent atmospheric data tape was constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in postflight performance assessments and represents the best estimate of the launch environment to the 400,000-ft altitude that was traversed by the STS-38 vehicle.

  7. Atmospheric environment for space shuttle (STS-33) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1990-01-01

    A summary is presented of selected atmospheric conditions observed near space shuttle STS-33 at launch time. STS-33 carried a DOD payload and the flight azimuth is denoted by a reference flight azimuth, since the actual flight azimuth is not known. Values of ambient pressure, temperature, moisture, ground winds, visual observations (clouds), and winds aloft are included. The sequence of pre-launch Jimsphere measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-33 vehicle ascent, was constructed. The STS-33 ascent atmospheric data tape was constructed by NASA-Marshall to provide an internally consistent data set for use in postflight performance assessments and represents the best estimates of the launch environment to the 400,000 ft altitude that was traversed by the STS-33 vehicle.

  8. Atmospheric environment for space shuttle (STS-36) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1990-01-01

    A summary of selected atmospheric conditions observed near space shuttle STS-36 launch time on February 28, 1990, at Kennedy Space Center, Florida was presented. STS-36 carried a Department of Defense payload and the flight azimuth is not known. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of pre-launch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-36 vehicle ascent was constructed. The STS-36 ascent atmospheric data tape was constructed to provide an internally consistent data set for use in postflight performance assessments and represent the best estimate of the launch environment to the 400,000 feet altitude that was traversed by the STS-36 vehicle.

  9. Atmospheric environment for Space Shuttle Atlantis (STS-39) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1992-01-01

    A summary is presented of selected atmospheric conditions observed near space shuttle Atlantis STS-39 launch time on 28 April 1991, at Kennedy Space Center, FL. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-39 vehicle ascent was constructed. The STS-39 ascent atmospheric data tape was constructed by NASA-Marshall to provide an internally consistent data set for use in postflight performance assessments and represents the best estimate of the launch environment to the 400,000 ft altitude that was traversed by the STS-39 vehicle.

  10. Atmospheric environment for Space Shuttle (STS-31) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1990-01-01

    A summary of selected atmospheric conditions observed near space shuttle STS-31 launch time on April 24, 1990, at Kennedy Space Center, Florida, are presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (clouds), and winds aloft are included. The sequence of pre-launch Jimsphere-measured vertical wind profiles is also presented. The final atmospheric tape, which consists if wind and thermodynamic parameters versus altitude, for STS-31 vehicle ascent was constructed. The STS-31 ascent atmospheric data tape was constructed to provide an internally consistent data set for use in postflight performance assessments and represent the best estimated of the launch environment to the 400,000 feet altitude that was traversed by the STS-31 vehicle.

  11. Atmospheric environment for Space Shuttle (STS-32) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1990-01-01

    A summary of selected atmospheric conditions observed near space shuttle STS-32 launch time on January 9, 1990, at Kennedy Space Center, Florida, are presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (clouds), and winds aloft are included. The sequence of pre-launch Jimsphere-measured vertical wind profiles is also presented. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-32 vehicle ascent was constructed. The STS-32 ascent atmospheric data tape was constructed to provide an internally consistent data set for use in postflight performance assessments and represents the best estimate of the launch environment that was traversed by the STS-32 vehicle.

  12. Atmospheric Environment for Space Shuttle (STS-28) Launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1990-01-01

    A summary is presented of selected atmospheric conditions observed near Space Shuttle STS-28 launch time on August 8, 1989. STS-28 carried a Department of Defense payload and the flight azimuth is denoted by a reference flight azimuth, since the actual flight azimuth is not known. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-28 vehicle ascent was constructed and represents the best estimate of the launch environment to 400,000 ft altitude that was traversed by the STS-28 vehicle. The STS-28 ascent atmospheric data tape was constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in post-flight performance assessments.

  13. Monitoring of contamination of atmospheric environment by radiation

    International Nuclear Information System (INIS)

    Atmospheric pollution has become a worldwide problem regardless of developed industrial nations and developing countries. In particular, the pollution due to automobile exhaust gas, the carcinogenic particles in diesel exhaust and their relation to various respiratory diseases are the problems. Nitrogen oxides and sulfur oxides in exhaust gas become the cause of acid rain. Radiation began to be utilized for the measurement of the concentration of floating particles and the amount of fallout dust, the forecast of the generation and diffusion of pollutants, the elucidation of the contribution of generation sources in wide areas and so on. In this report, the circumstances that radiation became to be utilized for monitoring atmospheric environment and the present status and the perspective of the radiation utilization in the field of the preservation of atmospheric environment are described. The progress of the method of measuring floating particles in Japan is explained. The automatic measurement of floating particles by β-ray absorption method and the application of β-ray absorption method to the measurement of the amount of fallout dust, generation source particles and the exposure to floating particles of individuals for health control are described. The utilization of radiation for real time monitoring, the investigation of the generation of blown-up dust, atmospheric diffusion experiment and the elucidation of the contribution of generation sources by PIXE radioactivation analysis are reported. (K.I.)

  14. Development of web-based environment for atmospheric dispersion modeling

    Czech Academy of Sciences Publication Activity Database

    Hofman, Radek; Pecha, Petr

    La Garde Park, Illinois, USA : American Nuclear Society, 2013. ISBN 978-0-89448-702-6. [International Topical Meeting on Probabilistic Safety Assessment and Analysis . Columbia, SC (US), 22.09.2013-27.09.2013] R&D Projects: GA MV(CZ) VG20102013018 Institutional support: RVO:67985556 Keywords : distributed computing * atmoshepric dispersion * web environment Subject RIV: DL - Nuclear Waste, Radioactive Pollution ; Quality http://library.utia.cas.cz/separaty/2013/AS/hofman-development of web -based environment for atmospheric dispersion modeling.pdf

  15. PATHFINDER: Probing Atmospheric Flows in an Integrated and Distributed Environment

    Science.gov (United States)

    Wilhelmson, R. B.; Wojtowicz, D. P.; Shaw, C.; Hagedorn, J.; Koch, S.

    1995-01-01

    PATHFINDER is a software effort to create a flexible, modular, collaborative, and distributed environment for studying atmospheric, astrophysical, and other fluid flows in the evolving networked metacomputer environment of the 1990s. It uses existing software, such as HDF (Hierarchical Data Format), DTM (Data Transfer Mechanism), GEMPAK (General Meteorological Package), AVS, SGI Explorer, and Inventor to provide the researcher with the ability to harness the latest in desktop to teraflop computing. Software modules developed during the project are available in the public domain via anonymous FTP from the National Center for Supercomputing Applications (NCSA). The address is ftp.ncsa.uiuc.edu, and the directory is /SGI/PATHFINDER.

  16. Atmospheric corrosion of metals in industrial city environment

    OpenAIRE

    Elzbieta Kusmierek; Ewa Chrzescijanska

    2015-01-01

    Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the s...

  17. Atmospheric pressure plasmas for aerosols processes in materials and environment

    OpenAIRE

    Borra, J.P.; Jidenko, N; Bourgeois, E

    2009-01-01

    Abstract The paper highlights applications of some atmospheric pressure plasmas (dc-corona, streamer and spark and ac-Dielectric Barrier Discharges) to aerosol processes for Materials and Environment (filtration, diagnostics). The production of vapor i.e. condensable gaseous species, leads to nano-sized particles by physical and chemical routes of nucleation in these AP plasmas: (i) when dc streamer and spark filamentary discharges as well as ac filamenta...

  18. The Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission

    Science.gov (United States)

    Spremo, Stevan; Turner, Mark; Caffrey, Robert T.; Hine, Butler Preston

    2010-01-01

    The Lunar Atmosphere and Dust Environment Explorer (LADEE) is a Lunar science orbiter mission currently under development to address the goals of the National Research Council decadal surveys and the recent "Scientific Context for Exploration of the Moon" (SCEM) [1] report to study the pristine state of the lunar atmosphere and dust environment prior to significant human activities. LADEE will determine the composition of the lunar atmosphere and investigate the processes that control its distribution and variability, including sources, sinks, and surface interactions. LADEE will also determine whether dust is present in the lunar exosphere, and reveal the processes that contribute to its sources and variability. These investigations are relevant to our understanding of surface boundary exospheres and dust processes throughout the solar system, address questions regarding the origin and evolution of lunar volatiles, and have potential implications for future exploration activities. LADEE employs a high heritage science instrument payload including a neutral mass spectrometer, ultraviolet spectrometer, and dust sensor. In addition to the science payloads, LADEE will fly a laser communications system technology demonstration that could provide a building block for future space communications architectures. LADEE is an important component in NASA's portfolio of near-term lunar missions, addressing objectives that are currently not covered by other U.S. or international efforts, and whose observations must be conducted before large-scale human or robotic activities irrevocably perturb the tenuous and fragile lunar atmosphere. LADEE will also demonstrate the effectiveness of a low-cost, rapid-development program utilizing a modular bus design launched on the new Minotaur V launch vehicle. Once proven, this capability could enable future lunar missions in a highly cost constrained environment. This paper describes the LADEE objectives, mission design, and technical

  19. Neutron-activation method of monitoring of the environment

    International Nuclear Information System (INIS)

    Full text: Estimation of technogenic influences of the industrial enterprises on an environment, in particular, on ground and underground waters, was carried out by the fragmentary analysis of their element structure. In the report application of neutron-activation analysis (NAA) for monitoring an environment is considered. The total contents of elements was determined by NAA method with use of a reactor such as WWR-SM. Values of factors of correlation (K) are calculated with use of the computer, by special algorithm and reception of numerical values between 30 elements in the samples selected by a traditional technique from more than 600 points in area of activity GMZ-2. The developed technique has allowed to reveal elements indicators of technogenic (As, Ag, Sb, W, Au), mixed (Mo, Ba, Hg) and natural (Sc, Fe, Co, Ni, Rb, Cs, REE, Hf, Th, U) origins. Change of the total contents of elements in underground waters which were selected from observant chinks quarterly within three years is investigated. The technique of definition of forms of a presence of elements in underground and the sewage, based on electrodialysis division of ions with use nuclear (on a basis polyethyleneterephtalate film) filters with a diameter of pores of 0,16x0,2 micrometres is developed

  20. Atmospheric environment for space shuttle (STS-34) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1989-01-01

    A summary of selected atmospheric conditions observed near space shuttle STS-34 launch time on October 18, 1989, at Kennedy Space Center, Florida is presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (clouds), and winds aloft are included. The sequence of pre-launch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters vs. altitude, for STS-34 vehicle ascent was constructed to provide an internally consistent data set for use in post-flight performance assessments. It represents the best estimates of the launch environment to the 400,000 feet altitude that was traversed by the STS-34 vehicle.

  1. The PWM auto-control circuit of neutron tube atmospheric pressure

    International Nuclear Information System (INIS)

    Ion source atmospheric pressure auto-control circuit for C/O logging neutron generator is introduced. The pulse circuit of ion source adopts zero-voltage quasi-resonant switch technique and the heating circuit for replenisher adopts PWM converter

  2. Modeling high-energy cosmic ray induced terrestrial and atmospheric neutron flux: A lookup table

    CERN Document Server

    Overholt, Andrew; Atri, Dimitra

    2013-01-01

    Under current conditions, the cosmic ray spectrum incident on the Earth is dominated by particles with energies < 1 GeV. Astrophysical sources including high energy solar flares, supernovae and gamma ray bursts produce high energy cosmic rays (HECRs) with drastically higher energies. The Earth is likely episodically exposed to a greatly increased HECR flux from such events, some of which lasting thousands to millions of years. The air showers produced by HECRs ionize the atmosphere and produce harmful secondary particles such as muons and neutrons. Neutrons currently contribute a significant radiation dose at commercial passenger airplane altitude. With higher cosmic ray energies, these effects will be propagated to ground level. This work shows the results of Monte Carlo simulations quantifying the neutron flux due to high energy cosmic rays at various primary energies and altitudes. We provide here lookup tables that can be used to determine neutron fluxes from primaries with total energies 1 GeV - 1 PeV...

  3. Atmospheric corrosion of metals in industrial city environment.

    Science.gov (United States)

    Kusmierek, Elzbieta; Chrzescijanska, Ewa

    2015-06-01

    Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the samples without pretreatment. The corrosion products determined with the SEM/EDS method prove that the most corrosive pollutants present in the industrial city air are SO2, CO2, chlorides and dust. PMID:26217736

  4. Atmospheric corrosion of metals in industrial city environment

    Directory of Open Access Journals (Sweden)

    Elzbieta Kusmierek

    2015-06-01

    Full Text Available Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the samples without pretreatment. The corrosion products determined with the SEM/EDS method prove that the most corrosive pollutants present in the industrial city air are SO2, CO2, chlorides and dust.

  5. The Dynamics of the Atmospheric Radiation Environment at Aviation Altitudes

    Science.gov (United States)

    Stassinopoulos, Epaminondas G.

    2004-01-01

    Single Event Effects vulnerability of on-board computers that regulate the: navigational, flight control, communication, and life support systems has become an issue in advanced modern aircraft, especially those that may be equipped with new technology devices in terabit memory banks (low voltage, nanometer feature size, gigabit integration). To address this concern, radiation spectrometers need to fly continually on a multitude of carriers over long periods of time so as to accumulate sufficient information that will broaden our understanding of the very dynamic and complex nature of the atmospheric radiation environment regarding: composition, spectral distribution, intensity, temporal variation, and spatial variation.

  6. Perspectives of extreme sample environment in neutron scattering and consequences for instrumentation

    Indian Academy of Sciences (India)

    Michael Steiner

    2008-11-01

    Because neutrons can penetrate bulky pieces of matter, increasingly complex sample environment is requested by the users of neutron beams. This corresponds to the ever-growing complexity of the scientific problems addressed by neutron scatterers. Until now such requirements could be satisfied by sample environment, which could be added to the instruments without major modifications. Now it becomes evident, that for certain applications further progress is possible only by bringing the neutrons to the sample environment instead of bringing the sample environment to the neutrons. As one of the first examples of this concept we will discuss the high field magnet (HFM), which Hahn-Meitner-Institute Berlin (HMI) and the National High Magnetic Field Laboratory Tallahassy (NHFML) are constructing jointly for BENSC at HMI. At BENSC the HMI has built in the meantime a dedicated instrument based on the TOF principle to be equipped with the HFM to enable experiments at fields up to 25 T.

  7. Atmospheric environment during maneuvering descent from Martian orbit

    Science.gov (United States)

    Tauber, Michael E.; Bowles, Jeffrey V.; Yang, Lily

    1989-10-01

    This paper presents an analysis of the atmospheric maneuvering capability of a vehicle designated to land on the Martian surface, together with an analysis of the entry environment encountered by the vehicle. A maximum lift/drag ratio of 2.3 was used for all trajectory calculations. The maximum achievable lateral ranges varied from about 3400 km to 2500 km for entry velocities of 5 km/s (from a highly elliptical Martian orbit) and 3.5 km/s (from a low-altitude lower-speed orbit), respectively. It is shown that the peak decelerations are an order of magnitude higher for the 5-km/s entries than for the 3.5-km/s entries. The vehicle entering at 3.5 km/s along a gliding trajectory encountered a much more benign atmospheric environment. In addition, the glider's peak deceleration was found to be only about 0.7 earth g, making the shallow flight path ideal for manned vehicles whose crews might be physically weakened by the long voyage to Mars.

  8. Atmospheric environment during maneuvering descent from Martian orbit

    Science.gov (United States)

    Tauber, Michael E.; Bowles, Jeffrey V.; Yang, Lily

    1989-01-01

    This paper presents an analysis of the atmospheric maneuvering capability of a vehicle designated to land on the Martian surface, together with an analysis of the entry environment encountered by the vehicle. A maximum lift/drag ratio of 2.3 was used for all trajectory calculations. The maximum achievable lateral ranges varied from about 3400 km to 2500 km for entry velocities of 5 km/s (from a highly elliptical Martian orbit) and 3.5 km/s (from a low-altitude lower-speed orbit), respectively. It is shown that the peak decelerations are an order of magnitude higher for the 5-km/s entries than for the 3.5-km/s entries. The vehicle entering at 3.5 km/s along a gliding trajectory encountered a much more benign atmospheric environment. In addition, the glider's peak deceleration was found to be only about 0.7 earth g, making the shallow flight path ideal for manned vehicles whose crews might be physically weakened by the long voyage to Mars.

  9. The Global Atmospheric Environment for the Next Generation

    Energy Technology Data Exchange (ETDEWEB)

    Dentener, F; Stevenson, D; Ellingsen, K; van Joije, T; Schultz, M; Amann, M; Atherton, C; Bell, N; Bergmann, D; Bey, I; Bouwman, L; Butler, T; Cofala, J; Collins, B; Drevet, J; Doherty, R; Eickhout, B; Eskes, H; Fiore, A; Gauss, M; Hauglustaine, D; Horowitz, L; Isaksen, I A; Josse, B; Lawrence, M; Krol, M; Lamarque, J F; Montanaro, V; Muller, J F; Peuch, V H; Pitari, G; Pyle, J; Rast, S; Rodriguez, J; Sanderson, M; Savage, N H; Shindell, D; Strahan, S; Szopa, S; Sudo, K; Van Dingenen, R; Wild, O; Zeng, G

    2005-12-07

    Air quality, ecosystem exposure to nitrogen deposition, and climate change are intimately coupled problems: we assess changes in the global atmospheric environment between 2000 and 2030 using twenty-five state-of-the-art global atmospheric chemistry models and three different emissions scenarios. The first (CLE) scenario reflects implementation of current air quality legislation around the world, whilst the second (MFR) represents a more optimistic case in which all currently feasible technologies are applied to achieve maximum emission reductions. We contrast these scenarios with the more pessimistic IPCC SRES A2 scenario. Ensemble simulations for the year 2000 are consistent among models, and show a reasonable agreement with surface ozone, wet deposition and NO{sub 2} satellite observations. Large parts of the world are currently exposed to high ozone concentrations, and high depositions of nitrogen to ecosystems. By 2030, global surface ozone is calculated to increase globally by 1.5 {+-} 1.2 ppbv (CLE), and 4.3 {+-} 2.2 ppbv (A2). Only the progressive MFR scenario will reduce ozone by -2.3 {+-} 1.1 ppbv. The CLE and A2 scenarios project further increases in nitrogen critical loads, with particularly large impacts in Asia where nitrogen emissions and deposition are forecast to increase by a factor of 1.4 (CLE) to 2 (A2). Climate change may modify surface ozone by -0.8 {+-} 0.6 ppbv, with larger decreases over sea than over land. This study shows the importance of enforcing current worldwide air quality legislation, and the major benefits of going further. Non-attainment of these air quality policy objectives, such as expressed by the SRES-A2 scenario, would further degrade the global atmospheric environment.

  10. X-ray spectra and atmospheric structures of bursting neutron stars

    International Nuclear Information System (INIS)

    I discuss atmospheric structures and emitted x-ray spectra of bursting neutron stars. The x-ray spectrum is deformed from the blackbody spectrum by Comptonization and by a strong energy dependence of absorptive opacities. The atmospheric structures deviate from those of the Eddington atmospheres due to the Compton heating-cooling. I construct color temperature vs. luminosity diagrams from the atmospheric models of neutron stars. Comparing these with observational ones, I obtain two relations among mass, radius, and distance of the x-ray bursters MXB 1636 - 536 and MXB 1608 - 522. I derive two possible sets of mass, radius, and distance of the x-ray burst source MXB 1636 - 536 taking into account of the 4.1-keV absorption line, theoretical mass-radius relation of the neutron star, and the distance to the galactic center. If the absorption line is due to Cr 23 M = 1.7 - 2.0 solar mass, R = 11 - 12 km, and d = 6.3 - 6.7 kpc, and if it is due to Fe 25, M = 1.8 - 2.1 solar mass, R = 8 - 10 km, and d = 5.8 - 6.4 kpc. (author)

  11. Detailed atmosphere modelling for the neutron star 1E1207.4-5209: Evidence of Oxygen/Neon atmosphere

    OpenAIRE

    Mori, Kaya; Hailey, Charles J,

    2003-01-01

    We present a comprehensive investigation of the two broad absorption features observed in the X-ray spectrum of the neutron star 1E1207.4-5209 based on a recent analysis of the 260 ksec XMM-Newton data by Mori et al. 2005. Expanding on our earlier work (Hailey & Mori 2002) we have examined all previously proposed atmospheric models for 1E1207.4-5209. Using our atomic code, which rapidly solves Schrodinger's equation for arbitrary ion in strong magnetic field (Mori & Hailey 2002), we have syst...

  12. Analysis by Monte Carlo simulations of the sensitivity to single event upset of SRAM memories under spatial proton or terrestrial neutron environment

    International Nuclear Information System (INIS)

    Electronic systems in space and terrestrial environments are subjected to a flow of particles of natural origin, which can induce dysfunctions. These particles can cause Single Event Upsets (SEU) in SRAM memories. Although non-destructive, the SEU can have consequences on the equipment functioning in applications requiring a great reliability (airplane, satellite, launcher, medical, etc). Thus, an evaluation of the sensitivity of the component technology is necessary to predict the reliability of a system. In atmospheric environment, the SEU sensitivity is mainly caused by the secondary ions resulting from the nuclear reactions between the neutrons and the atoms of the component. In space environment, the protons with strong energies induce the same effects as the atmospheric neutrons. In our work, a new code of prediction of the rate of SEU has been developed (MC-DASIE) in order to quantify the sensitivity for a given environment and to explore the mechanisms of failures according to technology. This code makes it possible to study various technologies of memories SRAM (Bulk and SOI) in neutron and proton environment between 1 MeV and 1 GeV. Thus, MC-DASIE was used with experiment data to study the effect of integration on the sensitivity of the memories in terrestrial environment, a comparison between the neutron and proton irradiations and the influence of the modeling of the target component on the calculation of the rate of SEU. (author)

  13. Scientific Visualization for Atmospheric Data Analysis in Collaborative Virtual Environments

    Science.gov (United States)

    Engelke, Wito; Flatken, Markus; Garcia, Arturo S.; Bar, Christian; Gerndt, Andreas

    2016-04-01

    1 INTRODUCTION The three year European research project CROSS DRIVE (Collaborative Rover Operations and Planetary Science Analysis System based on Distributed Remote and Interactive Virtual Environments) started in January 2014. The research and development within this project is motivated by three use case studies: landing site characterization, atmospheric science and rover target selection [1]. Currently the implementation for the second use case is in its final phase [2]. Here, the requirements were generated based on the domain experts input and lead to development and integration of appropriate methods for visualization and analysis of atmospheric data. The methods range from volume rendering, interactive slicing, iso-surface techniques to interactive probing. All visualization methods are integrated in DLR's Terrain Rendering application. With this, the high resolution surface data visualization can be enriched with additional methods appropriate for atmospheric data sets. This results in an integrated virtual environment where the scientist has the possibility to interactively explore his data sets directly within the correct context. The data sets include volumetric data of the martian atmosphere, precomputed two dimensional maps and vertical profiles. In most cases the surface data as well as the atmospheric data has global coverage and is of time dependent nature. Furthermore, all interaction is synchronized between different connected application instances, allowing for collaborative sessions between distant experts. 2 VISUALIZATION TECHNIQUES Also the application is currently used for visualization of data sets related to Mars the techniques can be used for other data sets as well. Currently the prototype is capable of handling 2 and 2.5D surface data as well as 4D atmospheric data. Specifically, the surface data is presented using an LoD approach which is based on the HEALPix tessellation of a sphere [3, 4, 5] and can handle data sets in the order of

  14. Time Evolution of Artificial Plasma Cloud in Atmospheric Environment

    Institute of Scientific and Technical Information of China (English)

    陆启明; 杨维纮; 刘万东

    2004-01-01

    By analyzing the time evolution of artificial plasma cloud in the high altitude of atmospheric environment, we found that there are two zones, an exponential attenuation zone and a linearly attenuating zone, existing in the spatial distribution of electron density of the artificial plasma clouds. The plasma generator's particle flux density only contributes to the exponential attenuation zone, and has no effect on the linear attenuation zone. The average electron density in the linear attenuation zone is about 10-5 of neutral particle density, and can diffuse over a wider area. The conclusion will supply some valuable references to the research of electromagnetic wave and artificial plasma interaction, the plasma invisibleness research of missile and special aerocraft,and the design of artificial plasma source.

  15. ATMOSPHERIC ENVIRONMENT CONDITIONS IN THE PLOIEŞTI MUNICIPALITY

    Directory of Open Access Journals (Sweden)

    MIHAELA FLORINA ŢÂMPU

    2015-10-01

    Full Text Available Since its beginnings Ploieşti has proved to be a city, a connection point between the most important Romanian and European routes, a place where the old traditions of the trade have been completed and developed perfectly at the same rhythm as the oil history. The history of the oil industry being known on the European level, the economy of Ploieşti has been closely connected to the oil resources of its neighboring areas and to their refineries. Ploieşti has been considered as “the most important oil refining center of SE Europe”. 150 years after the discovery of the first oil field near Ploieşti, the city has remained anchored in this industry - preponderantly the oil mining and processing industry and other industries related to this branch (machine building, electric equipment, maintenance etc.. The city’s population recorded a special increase until 1990, correlated with the intense development of its economy, as follows: 45,107 inhabitants in 1889; 56,460 in 1912; 77,341 in 1930; 96,229 in 1948; 316,856 in 1992 and then it decreased down to 300,358 in 2002 and 210,000 in 2011, to these numbers being associated - in the last decades - the metropolitan area, as well. At present, Ploieşti Municipality represents a center of industrial, commercial, touristic and cultural-scientific junction. As the economy developed and the population of Ploieşti Municipality and its surroundings increased, the quality of the urban environment has changed because of the soil pollution sources. Regarding the pollution of the atmospheric environment, some conditions related to the geographic position - respectively the relief of the Plain of Ploieşti and the climate - have had a somewhat favorable influence on the circulation of the atmospheric emissions.

  16. Fast Neutron Dosimeter for the Space Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Secondary neutrons make a significant contribution to the total absorbed dose received by space crews during long duration space missions However, only a limited...

  17. Fast Neutron Dosimeter for the Space Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Model calculations and risk assessment estimates indicate that secondary neutrons, with energies ranging between 0.5 to >150 MeV, make a significant contribution...

  18. Use of neutron activation analysis at the IBR-2 reactor for atmospheric monitoring

    International Nuclear Information System (INIS)

    The object of this work was the study of the possibilities of neutron activation analysis (NAA) for determination of elemental content of atmospheric aerosol. On examples of three Siberian regions it was shown that methodics of analysis allow to estimate the average level of suburban background (ALSB), scale of its regional, season and annual changes. Analysis of enrichment factors allows one to convince in presence of increased content of a row of heavy metals in atmospheric air of background regions what is the consequence of a global growing of technogenic impact

  19. Effects of atmospheric neutrons on advanced micro-electronic devices, standards and applications

    International Nuclear Information System (INIS)

    Since the 1980's, it is known that terrestrial cosmic rays, mainly reported as atmospheric neutrons, can penetrate the natural shielding of buildings, equipments and circuit package and induce soft errors in integrated circuits and breakdown of power devices. The high-energy neutron fluxes of interest, larger than 10 MeV, range between 10 particles/cm2/hour at sea level and 104 particles/cm2/hour at typical airplanes flight altitude of 30000 feet, with modulation due to solar flares. In the 1990's, the phenomenon has pervaded as a consequence of the road-map of electronic devices especially the down-scaling of transistor dimensions, the increase of signal bandwidth and the increase of the size of DRAM and SRAM memory, stand-alone or embedded on processors and system-on-chips. Failure-in-time and soft error rate became unacceptable. Test standards and design solutions have been proposed to maintain reliability of commercial products and improve those used in special high-reliability equipments such as avionic computers. The paper describes the atmospheric neutron flux, the effects in the main classes of devices and specific cases such as neutron induced single event upset observed in CMOS vs. CMOS/SOI and some mitigation issues. In this paper, a model called CCPM (critical cross-point model) is proposed to provide critical graphs of technology node sensitivity along the scaling trend of CMOS. (authors)

  20. Atmospheric corrosion of galvanized steel in a marine environment

    International Nuclear Information System (INIS)

    Atmospheric corrosion is the electrochemical process of metal deterioration from the action of atmospheric factors, both meteorological as well as chemical. Metals deteriorate due to their spontaneous oxidation when their surface is moistened with a film of condensed water, dew, fog or rain and this process leads to the formation of a protective film that acts as a physical barrier between the metal and the environment. However, this layer of corrosion can become a non protective film, due to a physical discharge or a partial dissolution of some soluble corrosion products of the material (galvanized steel) during rainfall or in condensed water on the material's surface. This process is known as metal runoff. In order to estimate the runoff process for galvanized steel and to study its behavior to atmospheric corrosion in a marine environment, samples of 10x10x0,6cm galvanized steel, with a coating thickness of 100 m Zn, were exposed in the city of Valparaiso, Region V, Chile. The atmospheric station is located at lat. 32AS and long. 71oW, classified according to ISO 9223 to 9226 as C2, S1 and P1, with a humidification time of 0.6 and chloride ion and sulfur dioxide content of 40.65 mgm-2day-1 and 7.18 mgm-2day-1, respectively. The deterioration of the galvanized steel was evaluated by weight loss measurements, determination of 'in situ' corrosion potential and morphology of the attack using scanning electron microscopy (SEM). The composition of the corrosion products was determined by X-ray diffraction (XRD). The runoff solutions collected after the rainfall events were analyzed with different techniques to determine the content of Cl- ions, SO4-2 and dissolved solids, and pH and conductivity were measured as well. The concentration of Zn+2 is obtained by atomic adsorption spectroscopy. After four months of exposure of the test pieces preliminary results show that the potential for corrosion of the galvanized steel increased over time, which corroborates the

  1. Study of occupational health impact of atmospheric pollution on exposed workers at an iron and steel complex by using neutron activation analysis of scalp hair

    International Nuclear Information System (INIS)

    The occupational health impact of atmospheric pollution on exposed workers at one iron and steel complex was studied by instrumental neutron activation analysis of workers' hair samples and medical examination. The experimental results indicate that there is a positive correlation between the high inhalation amounts of iron and other trace elements by the exposed workers and the symptom of their high blood pressure and hypoglycemia, which implies that the atmospheric environment polluted by iron and steel industry has an adverse health impact on the exposed workers. The measures to relieve and abate the occupational diseases caused by air-borne particulate matter should be taken. (author)

  2. Computational Transport Modeling of High-Energy Neutrons Found in the Space Environment

    Science.gov (United States)

    Cox, Brad; Theriot, Corey A.; Rohde, Larry H.; Wu, Honglu

    2012-01-01

    The high charge and high energy (HZE) particle radiation environment in space interacts with spacecraft materials and the human body to create a population of neutrons encompassing a broad kinetic energy spectrum. As an HZE ion penetrates matter, there is an increasing chance of fragmentation as penetration depth increases. When an ion fragments, secondary neutrons are released with velocities up to that of the primary ion, giving some neutrons very long penetration ranges. These secondary neutrons have a high relative biological effectiveness, are difficult to effectively shield, and can cause more biological damage than the primary ions in some scenarios. Ground-based irradiation experiments that simulate the space radiation environment must account for this spectrum of neutrons. Using the Particle and Heavy Ion Transport Code System (PHITS), it is possible to simulate a neutron environment that is characteristic of that found in spaceflight. Considering neutron dosimetry, the focus lies on the broad spectrum of recoil protons that are produced in biological targets. In a biological target, dose at a certain penetration depth is primarily dependent upon recoil proton tracks. The PHITS code can be used to simulate a broad-energy neutron spectrum traversing biological targets, and it account for the recoil particle population. This project focuses on modeling a neutron beamline irradiation scenario for determining dose at increasing depth in water targets. Energy-deposition events and particle fluence can be simulated by establishing cross-sectional scoring routines at different depths in a target. This type of model is useful for correlating theoretical data with actual beamline radiobiology experiments. Other work exposed human fibroblast cells to a high-energy neutron source to study micronuclei induction in cells at increasing depth behind water shielding. Those findings provide supporting data describing dose vs. depth across a water-equivalent medium. This

  3. Levitating atmospheres of Eddington-luminosity neutron stars I. Optically thin Thomson-scattering atmospheres

    CERN Document Server

    Wielgus, M; Sądowski, A; Narayan, R; Abramowicz, M

    2015-01-01

    In general relativity static gaseous atmospheres may be in hydrostatic balance in the absence of a supporting stellar surface, provided that the luminosity is close to the Eddington value. We construct analytic models of optically thin, spherically symmetric shells supported by the radiation pressure of a luminous central body in the Schwarzschild metric.

  4. Updated neutron spectrum characterization of SNL baseline reactor environments. Volume 1, Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, P.J.; Kelly, J.G.; Vehar, D.W.

    1994-04-01

    The neutron spectrum characteristics of the primary reactor environments are defined for use by facility customers and to provide an audit trail in support of current quality assurance initiatives. The neutron and gamma environments in the four primary customer environments at SPR-III and ACRR facilities are characterized in detail. Enough detail is provided on other frequently-used environments to support the definition of the 3-MeV and 1-MeV(Si) fluence provided on the Radiation Metrology Laboratory dosimetry reports.

  5. New calculations of the atmospheric cosmic radiation field - Results for neutron spectra

    International Nuclear Information System (INIS)

    The propagation of primary cosmic rays through the Earth's atmosphere and the energy spectra of the resulting secondary particles have been calculated using the Monte Carlo transport code FLUKA with several novel auxiliary methods. Solar-modulated primary cosmic ray spectra were determined through an analysis of simultaneous proton and helium measurements made on spacecraft or high-altitude balloon flights. Primary protons and helium ions are generated within the rigidity range of 0.5 GV-20 TV, uniform in cos2θ. For a given location, primaries above the effective angle-dependent geomagnetic cut-off rigidity, and re-entrant albedo protons, are transported through the atmosphere. Helium ions are initially transported using a separate transport code called HEAVY to simulate fragmentation. HEAVY interfaces with FLUKA to provide interaction starting points for each nucleon originating from a helium nucleus. Calculated cosmic ray neutron spectra and consequent dosimetric quantities for locations with a wide range of altitude (atmospheric depth) and geomagnetic cut-off are presented and compared with measurements made on a high-altitude aeroplane. Helium ion propagation using HEAVY and inclusion of re-entrant albedo protons with the incident primary spectra significantly improved the agreement of the calculated cosmic ray neutron spectra with measured spectra. These cosmic ray propagation calculations provide the basis for a new atmospheric ionising radiation (AIR) model for air-crew dosimetry, calculation of effects on microelectronics, production of cosmogenic radionuclides and other uses. (authors)

  6. X-ray bursting neutron star atmosphere models: spectra and color corrections

    CERN Document Server

    Suleimanov, V; Werner, K

    2010-01-01

    X-ray bursting neutron stars in low mass X-ray binaries constitute an appropriate source class to constrain masses and radii of neutron stars, but a sufficiently extended set of corresponding model atmospheres is necessary for these investigations. We computed such a set of model atmospheres and emergent spectra in a plane-parallel, hydrostatic, and LTE approximation with Compton scattering taken into account. The models were calculated for six different chemical compositions: pure hydrogen and pure helium atmospheres, and atmospheres with solar mix of hydrogen and helium, and various heavy element abundances Z = 1, 0.3, 0.1, and 0.01 Z_sun. For each chemical composition the models are computed for three values of surface gravity, log g =14.0, 14.3, and 14.6, and for 20 values of the luminosity in units of the Eddington luminosity, L/L_Edd, in the range 0.001--0.98. The emergent spectra of all models are redshifted and fitted by a diluted blackbody in the RXTE/PCA 3--20 keV energy band, and corresponding valu...

  7. Distributed data processing and analysis environment for neutron scattering experiments at CSNS

    CERN Document Server

    Tian, H L; Yan, L L; Tang, M; Hu, L; Zhao, D X; Qiu, Y X; Zhang, H Y; Zhuang, J; Du, R

    2016-01-01

    China Spallation Neutron Source (CSNS) is the first high performance pulsed neutron source in China, which will meet the increasing fundamental research and technique applications demands in the domestic and oversea. A new distributed data processing and analysis environment has been developed, which has generic functionalities for neutron scattering experiments. The environment consists of three parts, an object-oriented data processing framework adopting a data centered architecture, a communication and data caching system based on C/S paradigm, and a data analysis and visualization software providing the 2D/3D experimental data display. This environment will be widely applied in CSNS for live data processing and virtual neutron scattering experiments based on Monte Carlo methods.

  8. Neutron Environment Characterization of the Central Cavity in the Annular Core Research Reactor *

    Directory of Open Access Journals (Sweden)

    Parma Edward J.

    2016-01-01

    Full Text Available Characterization of the neutron environment in the central cavity of the Sandia National Laboratories' Annular Core Research Reactor (ACRR is important in order to provide experimenters with the most accurate spectral information and maintain a high degree of fidelity in performing reactor experiments. Characterization includes both modeling and experimental efforts. Building accurate neutronic models of the ACRR and the central cavity “bucket” environments that can be used by experimenters is important in planning and designing experiments, as well as assessing the experimental results and quantifying uncertainties. Neutron fluence characterizations of two bucket environments, LB44 and PLG, are presented. These two environments are used frequently and represent two extremes in the neutron spectrum. The LB44 bucket is designed to remove the thermal component of the neutron spectrum and significantly attenuate the gamma-ray fluence. The PLG bucket is designed to enhance the thermal component of the neutron spectrum and attenuate the gamma-ray fluence. The neutron characterization for each bucket was performed by irradiating 20 different activation foil types, some of which were cadmium covered, resulting in 37 different reactions at the peak axial flux location in each bucket. The dosimetry results were used in the LSL-M2 spectrum adjustment code with a 640-energy group MCNP-generated trial spectrum, self-shielding correction factors, the SNLRML or IRDFF dosimetry cross-section library, trial spectrum uncertainty, and trial covariance matrix, to generate a least-squares adjusted neutron spectrum, spectrum uncertainty, and covariance matrix. Both environment character-izations are well documented and the environments are available for use by experimenters.

  9. Neutron Environment Characterization of the Central Cavity in the Annular Core Research Reactor

    Science.gov (United States)

    Parma, Edward J.; Naranjo, Gerald E.; Lippert, Lance L.; Vehar, David W.

    2016-02-01

    Characterization of the neutron environment in the central cavity of the Sandia National Laboratories' Annular Core Research Reactor (ACRR) is important in order to provide experimenters with the most accurate spectral information and maintain a high degree of fidelity in performing reactor experiments. Characterization includes both modeling and experimental efforts. Building accurate neutronic models of the ACRR and the central cavity "bucket" environments that can be used by experimenters is important in planning and designing experiments, as well as assessing the experimental results and quantifying uncertainties. Neutron fluence characterizations of two bucket environments, LB44 and PLG, are presented. These two environments are used frequently and represent two extremes in the neutron spectrum. The LB44 bucket is designed to remove the thermal component of the neutron spectrum and significantly attenuate the gamma-ray fluence. The PLG bucket is designed to enhance the thermal component of the neutron spectrum and attenuate the gamma-ray fluence. The neutron characterization for each bucket was performed by irradiating 20 different activation foil types, some of which were cadmium covered, resulting in 37 different reactions at the peak axial flux location in each bucket. The dosimetry results were used in the LSL-M2 spectrum adjustment code with a 640-energy group MCNP-generated trial spectrum, self-shielding correction factors, the SNLRML or IRDFF dosimetry cross-section library, trial spectrum uncertainty, and trial covariance matrix, to generate a least-squares adjusted neutron spectrum, spectrum uncertainty, and covariance matrix. Both environment character-izations are well documented and the environments are available for use by experimenters. Work supported by the United States Department of Energy at Sandia National Laboratories. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned

  10. Scientific Visualization for Atmospheric Data Analysis in Collaborative Virtual Environments

    Science.gov (United States)

    Engelke, Wito; Flatken, Markus; Garcia, Arturo S.; Bar, Christian; Gerndt, Andreas

    2016-04-01

    1 INTRODUCTION The three year European research project CROSS DRIVE (Collaborative Rover Operations and Planetary Science Analysis System based on Distributed Remote and Interactive Virtual Environments) started in January 2014. The research and development within this project is motivated by three use case studies: landing site characterization, atmospheric science and rover target selection [1]. Currently the implementation for the second use case is in its final phase [2]. Here, the requirements were generated based on the domain experts input and lead to development and integration of appropriate methods for visualization and analysis of atmospheric data. The methods range from volume rendering, interactive slicing, iso-surface techniques to interactive probing. All visualization methods are integrated in DLR's Terrain Rendering application. With this, the high resolution surface data visualization can be enriched with additional methods appropriate for atmospheric data sets. This results in an integrated virtual environment where the scientist has the possibility to interactively explore his data sets directly within the correct context. The data sets include volumetric data of the martian atmosphere, precomputed two dimensional maps and vertical profiles. In most cases the surface data as well as the atmospheric data has global coverage and is of time dependent nature. Furthermore, all interaction is synchronized between different connected application instances, allowing for collaborative sessions between distant experts. 2 VISUALIZATION TECHNIQUES Also the application is currently used for visualization of data sets related to Mars the techniques can be used for other data sets as well. Currently the prototype is capable of handling 2 and 2.5D surface data as well as 4D atmospheric data. Specifically, the surface data is presented using an LoD approach which is based on the HEALPix tessellation of a sphere [3, 4, 5] and can handle data sets in the order of

  11. Atmospheric neutrons at 8.5-GV cutoff in the southern hemisphere

    International Nuclear Information System (INIS)

    We report here, for the first time, southern hemispheric measurements of the altitude, latitude, angle, and energy distributions of atmospheric neutrons from 5 to 80 MeV. The data were obtained with the University of California, Riverside, balloon-borne telescope flown from Alice Springs, Australia, on November 10, 1981, at 290 south geomagnetic latitude (SGML). The efficiencies required to evaluate the fluxes for both the upward and the downward moving neutrons were obtained from a Monte Carlo program tested against neutron calibrations. The counting rates of the upward and the downward moving neutrons increase from a residual altitude of 4 gcm2 to a maximum at 100 gcm2 and then decrease rapidly. These variations agree well with the previous results of Preszler et al. (1974) at 410 north geomagnetic latitude (NGML). The escape current calculated at 290 SGML, 8.5-GV cutoff, for neutron energies between 20 and 70 MeV, is 0.059 +- 0.008 neutronscm2 s, adding another point to the latitude distribution, in good agreement with the theoretical predictions of Merker (1972). The angular distributions at all altitudes are similar, with dips near 600 and 1300 from the zenith direction. The energy distributions decrease with energy at all altitudes but flatten at energies around 25 MeV. The albedo neutron current decreases as E/sup -1.61//sup +- //sup 0.28/ at 4.1 gcm2. These values are compared with the experimental results of Preszler et al. (1974, 1976), Lockwood et al. (1976, 1979) and Bhatt (1983, 1986) and to the theoretical results of Armstrong et al. (1973) and Merker (1972,1975). copyright American Geophysical Union 1988

  12. Analysis of a laboratory experiment on neutron generation by discharges in the open atmosphere

    Science.gov (United States)

    Babich, L. P.

    2015-10-01

    A recently reported laboratory experiment with a high-voltage long discharge in the open atmosphere producing neutrons "…up to energies above 10 MeV…" [Agafonov et al., Phys. Rev. Lett. 111, 115003 (2013), 10.1103/PhysRevLett.111.115003] is critically analyzed. Known elementary processes, namely, nuclear synthesis 2H(2H,n )3He and 2H(14N,n )15O , photonuclear, electrodisintegration Anm(e-,n )mprescripts>m n -1 and opposite to the β-decay e-(p+,n ) νe reactions, as well as unconventional mechanisms and the hypothetical increase in the nuclear synthesis cross sections are not capable of accounting for the neutron generation under conditions of the experiment analyzed. In particular, total energy yields of reactions 2H(2H,n )3He and 2H(14N,n )15O are less than the claimed neutron energy above 10 MeV. Trustworthiness of the neutron measurements on the basis of the available study of the C-39 track detectors behavior carried out by Faccini et al. [Eur. Phys. J. C 74, 2894 (2014), 10.1140/epjc/s10052-014-2894-3] in connection with claimed observations of neutron emission in electrolytic cells is discussed. Real-time measurements of x-ray and neutron pulses by Agafonov et al. are commented on using the thorough study of the x-ray emissions by discharges under similar conditions [Kochkin et al., J. Phys. D: Appl. Phys. 45, 425202 (2012), 10.1088/0022-3727/45/42/425202].

  13. Superburst Models for Neutron Stars with Hydrogen and Helium-Rich Atmospheres

    CERN Document Server

    Keek, L; Zand, J J M in 't

    2012-01-01

    Superbursts are rare day-long Type I X-ray bursts due to carbon flashes on accreting neutron stars in low-mass X-ray binaries. They heat the neutron star envelope such that the burning of accreted hydrogen and helium becomes stable, and the common shorter X-ray bursts are quenched. Short bursts reappear only after the envelope cools down. We study multi-zone one-dimensional models of the neutron star envelope, in which we follow carbon burning during the superburst, and we include hydrogen and helium burning in the atmosphere above. We investigate both the case of a solar composition and a helium-rich atmosphere. This allows us to study for the first time a wide variety of thermonuclear burning behavior as well as the transitions between the different regimes in a self-consistent manner. For solar composition, burst quenching ends much sooner than previously expected. This is because of the complex interplay between the 3-alpha, hot CNO, and CNO breakout reactions. Stable burning of hydrogen and helium transi...

  14. Mercury in the atmospheric and coastal environments of Mexico.

    Science.gov (United States)

    Ruelas-Inzunza, Jorge; Delgado-Alvarez, Carolina; Frías-Espericueta, Martín; Páez-Osuna, Federico

    2013-01-01

    In Mexico, published studies relating to the occurrence of Hg in the environment are limited. Among the main sources of Hg in Mexico are mining and refining of Auand Hg, chloralkali plants, Cu smelting, residential combustion of wood, carbo electric plants, and oil refineries. Hg levels are highly variable in the atmospheric compartment because of the atmospheric dynamics and ongoing metal exchange with the terrestrial surface. In atmospheric studies, Hg levels are usually reported as total gaseous Hg (TGM). In Mexico, TGM values ranged from 1.32 ng m-3 in Hidalgo state (a rural agricultural area) to 71.82 ng m-3 in Zacatecas state (an area where brick manufacturers use mining wastes as a raw material).Published information on mercury levels in the coastal environment comprise 21 studies, representing 21 areas, in which sediments constituted the substrate that was analyzed for Hg. In addition, water samples were analyzed for Hg in nine studies.Few studies exist on Hg levels in the Caribbean and in the southwest of the country where tourism is rapidly increasing. Hence, there is a need for establishing baseline levels of mercury in these increasingly visited areas. In regions where studies have been undertaken, Hg levels in sediments were highly variable. Variations in Hg sediment levels mainly result from geological factors and the varying degree of anthropogenic impacts in the studied areas. In areas that still have pristine or nearly pristine environments (e.g., coast, Baja California, Todos Santos Bay, and La Paz lagoon), sediment Hg levels ranged from Mexican coastal sites. In Urias lagoon (NW Mexico), moderate to high levels were found in the dissolved and suspended fraction, and these are related to shipping, the fishing industry, domestic effluents, and the presence of a thermoelectric plant. In Coatzacoalcos (SE Mexico), extremely elevated Hg levels were found during the decade of the 1970s. Low to moderate levels of Hg were measured in waters from the

  15. Observation of 2.45 MeV neutrons correlated with natural atmospheric lightning discharges by Lead-Free Gulmarg Neutron Monitor

    Science.gov (United States)

    Ishtiaq, P. M.; Mufti, S.; Darzi, M. A.; Mir, T. A.; Shah, G. N.

    2016-01-01

    The first experimental evidence of detecting the neutrons correlated with the natural atmospheric lightning discharges (NALD) was obtained with Lead-Free Gulmarg Neutron Monitor (LFGNM) operating at High Altitude Research Laboratory, Gulmarg, Kashmir, India, and was reported in the year 1985. The neutron observations still continue with LFGNM. However, the current configuration of LFGNM is the upgraded version of the system used earlier to record neutron bursts (in the recording period of 320 μs in four successive electronic gates of 80 μs each) supposedly originating from an NALD. In the current system the neutron recording time period/interval has been extended to 1260 μs with 63 successive gates of 20 μs each. The system also simultaneously records the differential times—maximum up to 14—between the consecutive strokes of a multistroke lightning flash. The distance between an NALD channel and LFGNM setup is determined empirically by making use of the time delay (td)/time of flight (TOF) measurement of the first detected neutron subsequent to the sensing of the electrostatic field variation caused by the initiation of an NALD in the ambient atmosphere of the LFGNM setup. Assuming a priori incident energy as 2.45 MeV of the detected neutrons supposedly generated due to the fusion of deuterium ions in the lightning discharge channel leads to quantifying the neutron emission flux if the NALD channel distance with respect to the LFGNM setup is established. In this paper we discuss the experiment and the time profiles of several of a large number of the major neutron burst events recorded with LFGNM in association with NALDs. Moreover, a rare and an extraordinary neutron burst event, in terms of its associated "td/TOF" of first detected neutron after triggering, recorded by this system is specifically discussed. In this event, the recorded TOF of 14 μs of the escaping neutron detected by the system immediately after getting triggered by the NALD that struck a

  16. Radiative properties of magnetic neutron stars with metallic surfaces and thin atmospheres

    CERN Document Server

    Potekhin, A Y; van Adelsberg, M; Werner, K

    2012-01-01

    The goal of this work is to develop a simple analytic description of the emission properties (spectrum and polarization) of the condensed, strongly magnetized surface of neutron stars. We have improved the method of van Adelsberg et al. (2005) (arXiv:astro-ph/0406001) for calculating the spectral properties of condensed magnetized surfaces. Using the improved method, we calculate the reflectivity of an iron surface at magnetic field strengths B \\sim (10^{12} - 10^{14}) G, with various inclinations of the magnetic field lines and radiation beam with respect to the surface and each other. We construct analytic expressions for the emissivity of this surface as functions of the photon energy, magnetic field strength, and the three angles that determine the geometry of the local problem. Using these expressions, we calculate X-ray spectra for neutron stars with condensed iron surfaces covered by thin partially ionized hydrogen atmospheres. We develop simple analytic descriptions of the intensity and polarization o...

  17. System for detecting neutrons in the harsh radiation environment of a relativistic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kruse, L.W.

    1978-06-01

    Newly developed detectors and procedures allow measurement of neutron yield and energy in the harsh radiation environment of a relativistic electron beam source. A new photomultiplier tube design and special gating methods provide the basis for novel time-of-flight and total-yield detectors. The technique of activation analysis is expanded to provide a neutron energy spectrometer. There is a demonstrated potential in the use of the integrated system as a valuable diagnostic tool to study particle-beam fusion, intense ion-beam interactions, and pulsed neutron sources for simulating weapons effects. A physical lower limit of 10/sup 8/ neutrons into 4..pi.. is established for accurate and meaningful measurements in the REB environment.

  18. System for detecting neutrons in the harsh radiation environment of a relativistic electron beam

    International Nuclear Information System (INIS)

    Newly developed detectors and procedures allow measurement of neutron yield and energy in the harsh radiation environment of a relativistic electron beam source. A new photomultiplier tube design and special gating methods provide the basis for novel time-of-flight and total-yield detectors. The technique of activation analysis is expanded to provide a neutron energy spectrometer. There is a demonstrated potential in the use of the integrated system as a valuable diagnostic tool to study particle-beam fusion, intense ion-beam interactions, and pulsed neutron sources for simulating weapons effects. A physical lower limit of 108 neutrons into 4π is established for accurate and meaningful measurements in the REB environment

  19. Heated-Atmosphere Airship for the Titan Environment: Thermal Analysis

    Science.gov (United States)

    Heller, R. S.; Landis, G. A.; Hepp, A. F.; Colozza, A. J.

    2012-01-01

    Future exploration of Saturn's moon Titan can be carried out by airships. Several lighter-than-atmosphere gas airships and passive drifting heated-atmosphere balloon designs have been studied, but a heated-atmosphere airship could combine the best characteristics of both. This work analyses the thermal design of such a heated-atmosphere vehicle, and compares the result with a lighter-than-atmosphere (hydrogen) airship design. A design tool was created to enable iteration through different design parameters of a heated-atmosphere airship (diameter, number of layers, and insulating gas pocket thicknesses) and evaluate the feasibility of the resulting airship. A baseline heated-atmosphere airship was designed to have a diameter of 6 m (outer diameter of 6.2 m), three-layers of material, and an insulating gas pocket thickness of 0.05 m between each layer. The heated-atmosphere airship has a mass of 161.9 kg. A similar mission making use of a hydrogen-filled airship would require a diameter of 4.3 m and a mass of about 200 kg. For a long-duration mission, the heated-atmosphere airship appears better suited. However, for a mission lifetime under 180 days, the less complex hydrogen airship would likely be a better option.

  20. Atmospheric environment for space shuttle (STS-51L) launch

    Science.gov (United States)

    Jasper, G. L.; Johnson, D. L.; Alexander, M.; Fichtl, G. H.; Batts, G. W.

    1986-01-01

    A summary is given of selected atmospheric conditions observed near Space Shuttle STS-51L launch time on January 28, 1986, at Kennedy Space Center, Florida. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of pre-launch Jimsphere measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-51L vehicle ascent has been constructed. The STS-51L ascent atmospheric data tape has been constructed by Marshall Space Flight Center's Atmospheric Sciences Division to provide an internally consistent data set for use in post flight performance assessments.

  1. Atmospheric environment for Space Shuttle (STS-51D)

    Science.gov (United States)

    Jasper, G. L.; Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1985-01-01

    A summary of selected atmospheric conditions observed near the space shuttle STS-51D launch time on April 12, 1985, at Kennedy Space Center Florida is presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given in this report. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-51D vehicle ascent is constructed. The STS-51D ascent atmospheric data tape is compiled by Marshall Space Flight Center's Atmospheric Sciences Division to provide an internally consistent data set for use in post-flight performance assessments.

  2. Atmospheric environment for space shuttle (STS-51B) launch

    Science.gov (United States)

    Jasper, G. L.; Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1985-01-01

    A summary of selected atmospheric conditions observed near space shuttle STS-51B launch time on April 29, 1985, at Kennedy Space Center Florida is presented. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-51B vehicle ascent was constructed. The STS-51B ascent atmospheric data tape was constructed by Marshall Space Flight Center's Atmospheric Sciences Division to provide an internally consistent data set for use in post flight performance assessments.

  3. Atmospheric environment for Space Shuttle (STS-41G) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Jasper, G.; Batts, G. W.

    1984-01-01

    Selected atmospheric conditions that were observed near Space Shuttle STS-41G launch time on October 5, 1984 at Kennedy Space Center in Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual obsrvations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape consisting of wind and thermodynamic parameters versus altitude for STS-41G vehicle ascent was constructed. The STS-41G ascent atmospheric data tape was constructed. The STS-41G ascent atmospheric data tape was constructed by Marshall Space Flight Center's Atmospheric Sciences Division to provide an internally consistent data set for use in post flight performance assessments.

  4. Determination of chemical pollutants in the atmosphere of the Valley of Toluca by neutron activation analysis

    International Nuclear Information System (INIS)

    The studies about the presence of contaminants in the atmosphere of diverse cities have been increased widely because to the problems that those cause to public health. Because of this in 1986 was made an Atmospheric Monitoring Program in the Valley of Toluca including the city of Toluca and Toluca- Lerma industrial corridor. That program consist of a preliminary net of sampling for the recollection of total suspended particles on glass-fiber filters, the sampling was performed two times a week in five different zones. To date have been analyzed some of these filters by atomic absorption in the Chemistry School of the Mexico's State University. In this work, is showed the establishment of chemical treatment technique and the results of quantitative analysis through neutron activation in filters of recent monitoring. (Author)

  5. Atmospheric environment for space shuttle (STS-26) launch

    Science.gov (United States)

    Jasper, G. L.; Johnson, D. L.; Batts, G. W.

    1989-01-01

    A summary of selected atmospheric conditions observed near Space Shuttle STS-26 launch time on September 29, 1988, at Kennedy Space Center, Florida is given. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of pre-launch Jimsphere measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-26 vehicle ascent has been constructed. The STS-26 ascent atmospheric data tape has been constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in post-flight performance assessments.

  6. Atmospheric environment for space shuttle (STS-51C) launch

    Science.gov (United States)

    Jasper, G.; Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1985-01-01

    Selected atmospheric conditions observed near space shuttle STS-51C launch time on January 24, 1985, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles are presented. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-51C vehicle ascent was constructed. The STS-51C ascent atmospheric data tape was constructed to provide an internally consistent data set for use in postflight performance assessments.

  7. Atmospheric environment for Space Shuttle (STS-51A) launch

    Science.gov (United States)

    Johnson, D. L.; Jasper, G.; Hill, C. K.; Batts, G. W.

    1984-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-51A launch time on November 8, 1984, are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is reported. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-51A vehicle ascent was constructed. The STS-51A ascent atmospheric data tape is constructed to provide an internally consistent data set for use in postflight performance assessments.

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

    OpenAIRE

    LIU, JUAN; Shi, Jiulin; Tang, Yijun; Zhu, Kaixing; Ge, Yuan; Chen, Xuegang; He, Xingdao; Liu, Dahe

    2014-01-01

    The attenuation coefficient of 532 nm light in water under different atmospheric conditions was investigated. Measurements were made over a two-year period at the same location and show that the attenuation coefficient is significantly influenced by the atmospheric environment. It is lowest when the atmospheric pressure is high and temperature is low, and is highest when the atmospheric pressure is low and temperature is high. The maximum attenuation coefficient of pure water in these studies...

  9. Model atmospheres and radiation of magnetic neutron stars: Anisotropic thermal emission

    Science.gov (United States)

    Pavlov, G. G.; Shibanov, Yu. A.; Ventura, J.; Zavlin, V. E.

    1994-01-01

    We investigate the anisotropy of the thermal radiation emitted by a surface element of a neutron star atmosphere (e.g., by a polar cap of a radio pulsar). Angular dependences of the partial fluxes at various photon energies, and spectra at various angles are obtained for different values of the effective temperature T(sub eff) and magnetic field strength B, and for different directions of the magnetic field. It is shown that the local radiation of the magnetized neutron star atmospheres is highly anisotropic, with the maximum flux emitted in the magnetic field direction. At high B the angular dependences in the soft X-ray range have two maxima, a high narrow peak along B and a lower and broader maximum at intermediate angles. The radiation is strongly polarized, the modulation of the degree of polarization due to the rotation of the neurtron star may be much higher than that for the radiative flux. The results obtained are compared with recent ROSAT observations of the thermal-like radiation from the radio pulsars PSR 1929+10 and PSR J0437-4715.

  10. Atmospheric environment for space shuttle (STS-29) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1989-01-01

    This report presents a summary of selected atmospheric conditions observed near Space Shuttle STS-29 launch time on March 13, 1989, at Kennedy Space Center, Florida. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of pre-launch Jimsphere-measured vertical wind profiles is given in this report. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-29 vehicle ascent has been constructed. The STS-29 ascent atmospheric data tape has been constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in post-flight performance assessments.

  11. Atmospheric environment for Space Shuttle (STS-27) launch

    Science.gov (United States)

    Jasper, G. L.; Johnson, D. L.; Batts, G. W.

    1989-01-01

    Selected articles on atmospheric conditions observed near Space Shuttle STS-27 launch time on December 2, 1988, at Kennedy Space Center, Florida are summarized. STS-27 carried a Department of Defense payload and the flight azimuth in this report will be denoted by reference flight azimuth, since the actual flight azimuth is not known. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of pre-launch Jimsphere-measured vertical wind profiles is given. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-27 vehicle ascent was constructed. The STS-27 ascent atmospheric data tape was constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in post-flight performance assessments.

  12. Atmospheric environment for space shuttle (STS-30) launch

    Science.gov (United States)

    Jasper, G. L.; Batts, G. W.

    1989-01-01

    This report presents a summary of selected atmospheric conditions observed near Space Shuttle STS-30 launch time on May 4, 1989, at Kennedy Space Center, Florida. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of pre-launch Jimsphere-measured vertical wind profiles is given in this report. The final atmospheric tape, which consists of wind and thermodynamic parameters versus altitude, for STS-30 vehicle ascent has been constructed. The STS-30 ascent atmospheric data tape has been constructed by Marshall Space Flight Center's Earth Science and Applications Division to provide an internally consistent data set for use in post-flight performance assessments.

  13. Atmospheric environment for Space Shuttle (STS-41D) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Jasper, G.; Batts, G. W.

    1984-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-41D launch time on August 30, 1984, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given as well as wind and thermodynamic parameters representative of surface and aloft conditions in the SRB descent/impact ocean area. Final atmospheric tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-41D vehicle ascent and SRB descent/impact were constructed. The STS-41D ascent meteorological data tape was constructed by Marshall Space Flight Center's Atmospheric Science Division to provide an internally consistent data set for use in post flight performance assessments.

  14. Soft X-ray spectral fits of Geminga with model neutron star atmospheres

    Science.gov (United States)

    Meyer, R. D.; Pavlov, G. G.; Meszaros, P.

    1994-01-01

    The spectrum of the soft X-ray pulsar Geminga consists of two components, a softer one which can be interpreted as thermal-like radiation from the surface of the neutron star, and a harder one interpreted as radiation from a polar cap heated by relativistic particles. We have fitted the soft spectrum using a detailed magnetized hydrogen atmosphere model. The fitting parameters are the hydrogen column density, the effective temperature T(sub eff), the gravitational redshift z, and the distance to radius ratio, for different values of the magnetic field B. The best fits for this model are obtained when B less than or approximately 1 x 10(exp 12) G and z lies on the upper boundary of the explored range (z = 0.45). The values of T(sub eff) approximately = (2-3) x 10(exp 5) K are a factor of 2-3 times lower than the value of T(sub eff) obtained for blackbody fits with the same z. The lower T(sub eff) increases the compatibility with some proposed schemes for fast neutrino cooling of neutron stars (NSs) by the direct Urca process or by exotic matter, but conventional cooling cannot be excluded. The hydrogen atmosphere fits also imply a smaller distance to Geminga than that inferred from a blackbody fit. An accurate evaluation of the distance would require a better knowledge of the ROSAT Position Sensitive Proportional Counter (PSPC) response to the low-energy region of the incident spectrum. Our modeling of the soft component with a cooler magnetized atmosphere also implies that the hard-component fit requires a characteristic temperature which is higher (by a factor of approximately 2-3) and a surface area which is smaller (by a factor of 10(exp 3), compared to previous blackbody fits.

  15. Urban Areas--Partial Creators of Their Own Atmospheric Environment

    Science.gov (United States)

    Marotz, Glen A.

    1975-01-01

    This article describes typical urban-rural atmospheric differences, focuses on heat islands as an example of observable alternation-response effects, and briefly describes some simple exercises which are intended to illustrate the reason for such temperature differences. (Author/DE)

  16. Development of propulsion for high atmospheric pressure or dense environments

    Science.gov (United States)

    Varsi, G.; Back, L. H.; Dowler, W. L.

    1973-01-01

    The development of a propulsion system that employs a detonating propellant is described, and the need for such a system and its use in certain planetary atmospheres are demonstrated. A theoretical formulation of the relevant gas-dynamic processes was developed, and a related series of experimental tests were pursued.

  17. Initial Atmospheric Corrosion of Carbon Steel in Industrial Environment

    Science.gov (United States)

    Han, Wei; Pan, Chen; Wang, Zhenyao; Yu, Guocai

    2015-02-01

    The initial corrosion behavior of carbon steel subjected to Shenyang industrial atmosphere has been investigated by weight-loss measurement, scanning electron microscopy observation, x-ray diffraction, auger electron spectroscopy, and electron probe microanalysis. The experimental results reveal that the corrosion kinetics of the initial corrosion of carbon steel in industrial atmosphere follows empirical equation D = At n , and there is a corrosion rate transition from corrosion acceleration to deceleration; the corrosion products are composed of γ-FeOOH, α-FeOOH, Fe3O4, as well as FeS which is related to the existence of sulfate-reducing bacteria in the rust layers. The effect of dust particles on the corrosion evolution of carbon steel has also been discussed.

  18. Field and data analysis studies related to the atmospheric environment

    Science.gov (United States)

    Kidder, Stanley; Mach, Douglas; Bailey, Jeff; Stewart, Michael; Slaton, Dave; Buechler, Dennis; Botts, Michael; Collins, Laurie

    1994-01-01

    This report summarizes work on a broad array of projects including: (1) applications of meteorological and/or oceanographic satellites; (2) improvement of the current set of NASA/USAF lightning related launch commit criteria rules; (3) the design, building, testing and deployment of a set of cylindrical field mills for aircraft use; (4) the study of marginal electrification storm conditions in relationship to the current launch commit rules for the space shuttle and various other launch vehicles using an instrumented aircraft; (5) support of the DC-8 and ER-2 lightning instrument package as part of both the Tropical Ocean - Global Atmospheric/Coupled Ocean-Atmospheric Response Experiment and the Convection and Moisture Experiment; (6) design of electronic circuitry and microprocessor firmware for the NASA Advanced Ground Based Field Mill; (7) design and testing of electronic and computer instrumentation for atmospheric electricity measurements; (8) simulating observations from a lightning imaging sensor on the Tropical Rainfall Measuring satellite; and (9) supporting scientific visualization and the development of computer software tools.

  19. Multi-scale atmospheric environment modelling for urban areas

    OpenAIRE

    Baklanov, A. A.; Nuterman, R.B.

    2009-01-01

    Modern supercomputers allow realising multi-scale systems for assessment and forecasting of urban meteorology, air pollution and emergency preparedness and considering nesting with obstacle-resolved models. A multi-scale modelling system with downscaling from regional to city-scale with the Environment – HIgh Resolution Limited Area Model (Enviro-HIRLAM) and to micro-scale with the obstacle-resolved Micro-scale Model for Urban Environment (M2UE) is suggested and demonstrated. The M2...

  20. Radiation exposure of airline crew members to the atmospheric ionizing radiation environment

    International Nuclear Information System (INIS)

    All risk assessment techniques for possible health effects from low dose rate radiation exposure should combine knowledge both of the radiation environment and of the biological response, whose effects (e.g. carcinogenesis) are usually evaluated through mathematical models and/or animal and cell experiments. Data on human exposure to low dose rate radiation exposure and its effects are not readily available, especially with regards to stochastic effects, related to carcinogenesis and therefore to cancer risks, for which the event probability increases with increasing radiation exposure. The largest source of such data might be airline flight personnel, if enrolled for studies on health effects induced by the cosmic-ray generated atmospheric ionizing radiation, whose total dose, increasing over the years, might cause delayed radiation-induced health effects, with the high-LET and highly ionizing neutron component typical of atmospheric radiation. In 1990 flight personnel has been given the status of 'occupationally exposed to radiation' by the International Commission for Radiation Protection (ICRP), with a received radiation dose that is at least twice larger than that of the general population. The studies performed until now were limited in scope and cohort size, and moreover no information whatsoever on radiation occupational exposure (e.g. dose, flight hours, route haul, etc.) was used in the analysis, so no correlation has been until now possible between atmospheric ionizing radiation and (possibly radiation-induced) observed health effects. Our study addresses the issues, by considering all Italian civilian airline flight personnel, both cockpit and cabin crew members, with about 10,000 people selected, whose records on work history and actual flights (route, aircraft type, date, etc. for each individual flight for each person where possible) are considered. Data on actual flight routes and profiles have been obtained for the whole time frame. The actual dose

  1. The role of neutron activation analysis for trace elements characterization, analysis and certification in atmospheric particulates

    International Nuclear Information System (INIS)

    The Neutron Activation Analysis (NAA) owns these requirements and is universally accepted as one of the most reliable analytical tools for trace and ultratrace elements determination. Its use in trace elements atmospheric pollution related studies has been and is still extensive as can be demonstrate by several specific works and detailed reviews. In this work, the application of this nuclear technique, in solving a series of different analytical problems related to trace elements in air pollution processes is reported. Examples and results are given on the following topics: characterization of urban and rural airborne particulate samples; particles size distribution in the different inhalable and respirable fractions (PM10 and PM 2.5); certification of related Standard Reference Materials for data quality assurance. (author)

  2. Bromine determination by neutron activation analysis and its distribution in the atmosphere

    International Nuclear Information System (INIS)

    Bromine, one of the main participants in ozone layer destruction, is 10 to 100 times more effective than chlorine. There are two principal sources of methyl bromide emissions: the oceans and some pesticides that are used in farming. Bromine was detected in 'premium' and 'magna sin' gasolines (2.86±0.96 and 1.54±0.38 ppm, respectively) as well as in condensed water found in exhaust pipes of vehicles. In addition, samples of rainwater were also analyzed to determine atmospheric bromine concentration. In water samples Br concentrations ranging from 2.09 to 0.06 ppm were found. The techniques utilised were neutron activation analysis and high voltage electrophoresis, the latter to determine the chemical form of bromine in condensed water samples. Finally, suspended particles from rainwater were also analysed by scanning electron microscopy (SEM). (author)

  3. Vapour phase mercury in the atmosphere. Methodology for instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Atmospheric gas phase mercury was collected on commercial charcoal by a mercury collection apparatus in Antalya, on the Mediterranean coast of Turkey. Because of the high collection efficiency due to its high surface area and low blank concentration for mercury and other metals, activated coconut charcoal was used as a sorbent material. Ozone was also monitored automatically during the collection period. Instrumental neutron activation analysis was used as the analytical technique. The collected charcoal samples were irradiated with neutrons at the CNAEM reactor with a flux of 1.1013 n·cm-2·s-1. The 77 keV gamma ray energy of 197Hg (T1/2 = 2.672 d) and 279 keV gamma ray energy of 203Hg (T1/2 = 46.61 d) isotopes were analysed separately. The 75Se correction for 203Hg was made because of interfering gamma ray energy. The average concentration of gas phase mercury was found to be 3.7 ± 1.5 ng·m-3. The correlation with other gas phase pollutants was also investigated. (author)

  4. Inferring atmospheric weather conditions in volcanic environments using infrasound

    Science.gov (United States)

    Ortiz, H. D.; Johnson, J. B.; Ruiz, M. C.

    2015-12-01

    We use infrasound produced by Tungurahua Volcano (Ecuador) to infer local time-varying atmospheric conditions, which can be used to improve gas flux measurements and tephra dispersal modeling. Physical properties of the atmosphere, including wind and temperature (which controls adiabatic sound speed), can be quantified by studying the travel times of acoustic waves produced during volcanic activity. The travel times between Tungurahua's vent and five infrasound stations located in a network configuration over an area of 90 km2 were used in this study. We are able to quantify the arrival time differences of acoustic waves for ten unique station pairs and use this information to model the average speed of sound between source and receiver. To identify what parameters best fit the observed arrival times, we perform a grid search for a homogeneous two-dimensional wind velocity as well as for air temperature. Due to travel time dependence on the specific path taken by waves, we account for topography using a 5 meter resolution digital elevation model of Tungurahua. To investigate the time-varying atmospheric structure we use data recorded at Tungurahua volcano, during a strombolian eruptive phase in August 2012, however the methodology can be applied to continuous network infrasound data collected since July 2006 as part of the Japanese-Ecuadorian Cooperation Project: "Enhancement of the Volcano Monitoring Capacity in Ecuador". We propose that the computation of wind velocities will help to improve gas flux measurements that are based on remote sensing techniques like Differential Optical Absorption Spectroscopy (DOAS), resulting in better estimates of sulfur fluxes that can then be related to magma fluxing into the volcanic system. Further, wind field quantification close to the volcano can improve numerical models that are used to forecast tephra deposits, thereby helping to mitigate their effect on inhabitants, infrastructure, livestock, and crops.

  5. An interactive parallel programming environment applied in atmospheric science

    Science.gov (United States)

    vonLaszewski, G.

    1996-01-01

    This article introduces an interactive parallel programming environment (IPPE) that simplifies the generation and execution of parallel programs. One of the tasks of the environment is to generate message-passing parallel programs for homogeneous and heterogeneous computing platforms. The parallel programs are represented by using visual objects. This is accomplished with the help of a graphical programming editor that is implemented in Java and enables portability to a wide variety of computer platforms. In contrast to other graphical programming systems, reusable parts of the programs can be stored in a program library to support rapid prototyping. In addition, runtime performance data on different computing platforms is collected in a database. A selection process determines dynamically the software and the hardware platform to be used to solve the problem in minimal wall-clock time. The environment is currently being tested on a Grand Challenge problem, the NASA four-dimensional data assimilation system.

  6. Atmospheric environment for Space Shuttle (STS-3) launch

    Science.gov (United States)

    Johnson, D. L.; Brown, S. C.; Batts, G. W.

    1982-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-3 launch time on March 22, 1982, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prlaunch Jimsphere measured vertical wind profiles and the wind and thermodynamic parameters measured at the surface and aloft in the SRB descent/impact ocean area are presented. Final meteorological tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-3 vehicle ascent and SRB descent were constructed. The STS-3 ascent meteorological data tape is constructed.

  7. Atmospheric environment for space shuttle (STS-13) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Jasper, G.; Batts, G. W.

    1984-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-13 launch time on April 6, 1984, at Kennedy Space Center Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given. The final meteorological tape, which consists of wind and thermodynamic parameters versus altitude, for STS-13 vehicle ascent was constructed by Marshall Space Flight Center in response to shuttle task agreement No. 561-81-22-368 with Johnson Space Center.

  8. Atmospheric environment for Space Shuttle (STS-4) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1982-01-01

    Selected atmospheric conditions observed near space shuttle STS-4 launch time on June 27, 1982, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given as well as the wind and thermodynamic parameters measured at the surface and aloft in the SRB descent/impact ocean area. Final meteorological tapes, which consist of wind descent were constructed. The STS-4 ascent meteorological data tape was constructed by Marshall Space Flight Center in response to shuttle task agreement No. 989-13-22-368 with Johnson Space Center.

  9. Atmospheric environment for Space Shuttle (STS-11) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1984-01-01

    Atmospheric conditions observed near Space Shuttle STS-11 launch time on February 3, 1984, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles are reported. Wind and thermodynamic parameters representative of surface and aloft conditions in the SRB descent/impact ocean area are presented. Meteorological tapes, which consist of wind and thermodynamic parameters vesus altitude, for STS-11 vehicle ascent and SRB descent/impact were constructed.

  10. Atmospheric environment for space shuttle (STS-8) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Turner, R. E.; Batts, G. W.

    1983-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-8 launch time on August 30, 1983, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given. Also presented are wind and thermodynamic parameters representative of surface and aloft conditions in the SRB descent/impact ocean area. Final meteorological tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-8 vehicle ascent and SRB descent/impact were constructed. The STS-8 ascent meteorological data tape was constructed.

  11. Atmospheric environment for Space Shuttle (STS-2) launch

    Science.gov (United States)

    Johnson, D. L.; Brown, S. C.

    1981-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-2 launch time on November 12, 1981, or Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given in this report. Wind and thermodynamic parameters measured at the surface and aloft in the SRB descent/impact ocean area are also presented. Final meteorological tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-2 vehicle ascent and SRB descent have been constructed. The STS-2 ascent meteorological data tape was constructed.

  12. Atmospheric environment for space shuttle (STS-1) launch

    Science.gov (United States)

    Johnson, D. L.; Jasper, G.; Brown, S. C.

    1981-01-01

    Atmospheric conditions near space shuttle STS-1 launch time on April, 12, 1981, at Kennedy Space Center, Florida, are reported. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is presented. Also presented are the wind and thermodynamic parameters measured at the surface and aloft in the SRB descent/impact ocean area. Final meteorological data tapes for STS-1 vehicle ascent, and SRB descent have been constructed which consist of wind and thermodynamic parameters versus altitude.

  13. Atmospheric environment for Space Shuttle (STS-9) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1984-01-01

    This report presents a summary of selected atmospheric conditions observed near Space Shuttle STS-9 launch time on November 28, 1983, at Kennedy Space Center, Florida. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given in this report. The final meteorological tape, which consists of wind and thermodynamic parameters versus altitude, for STS-9 vehicle ascent has been constructed. The STS-9 ascent meteorological data tape has been constructed by Marshall Space Flight Center in response to Shuttle task agreement No. 561-81-22-368 with Johnson Space Center.

  14. What the Cited and Citing Environments Reveal of "Advances in Atmospheric Sciences"?

    OpenAIRE

    Aolan, Shi; Leydesdorff, Loet

    2010-01-01

    The networking ability of journals reflects their academic influence among peer journals. This paper analyzes the cited and citing environments of the journal--Advances in Atmospheric Sciences--using methods from social network analysis. The journal has been actively participating in the international journal environment, but one has a tendency to cite papers published in international journals. Advances in Atmospheric Sciences is intensely interrelated with international peer journals in ter...

  15. Atmospheric corrosion of nickel in various outdoor environments

    International Nuclear Information System (INIS)

    As part of a field exposure program in the north-west of France on atmospheric corrosion of metal and alloys, this study presents the results of the behaviour of nickel panels exposed in industrial, urban and rural atmospheres. Mass measurements were investigated during the exposure and adherent corrosion layers were followed by means of several methods of analysis: Fourier transform infrared reflection-absorption spectroscopy, X-ray diffraction and scanning electron microscopy with X-ray microanalysis. In order to determine all the chemical species formed in the corrosion layers, corrosion products released from the surface by rainfall were also studied by collecting the streaming water from the nickel surfaces. Anionic and cationic quantities in the streaming water were determined respectively with ionic chromatography and polarography. The nickel attack appears as a pitting corrosion process accompanied by the formation of soluble corrosion products in dry exposure periods, these being regularly dissolved by rainfall events. Pits are associated with the formation of nickel salts, mainly sulphates and chlorides with small amounts of nitrate, and surrounded by carbonate species. The corrosion rate increases from rural to industrial areas

  16. Temporal distribution of tritium in the atmospheric environment of Mumbai

    International Nuclear Information System (INIS)

    Atmospheric Tritium level in the air moisture around Mumbai was estimated at several locations covering a radial distance of 20 km from the discharge point of CIRUS at BARC. Samples were collected by cold finger method from selected locations at 1 meter above ground level from 1.6 km to 20 km radial distance over a period of 3 years 2007-2009; during pre-monsoon, monsoon and post-monsoon seasons. Tritium was estimated in the air moisture by Ultra Low level Liquid Scintillation Spectrometer. The minimum detectable limit for the air moisture samples was 0.02 Eq/m3. Air tritium level was found to be maximum at the nearby locations during monsoon. However, during post-monsoon season the levels were higher at distances >3 km. In general, tritium level in the atmospheric air was in the range of 0.02-2.29 Bq/m3. The dose due to inhalation was observed to be in the range of 8.66E-8 to 9.9E-6 Sv/y which is very much lower than the prescribed limit. (author)

  17. The lunar atmosphere and dust environment explorer mission (LADEE)

    CERN Document Server

    Russell, Christopher

    2015-01-01

    This volume contains five articles describing the mission and its instruments.  The first paper, by the project scientist Richard C. Elphic and his colleagues, describes the mission objectives, the launch vehicle, spacecraft and the mission itself.  This is followed by a description of LADEE’s Neutral Mass Spectrometer by Paul Mahaffy and company.  This paper describes the investigation that directly targets the lunar exosphere, which can also be explored optically in the ultraviolet.  In the following article Anthony Colaprete describes LADEE’s Ultraviolet and Visible Spectrometer that operated from 230 nm to 810 nm scanning the atmosphere just above the surface.  Not only is there atmosphere but there is also dust that putatively can be levitated above the surface, possibly by electric fields on the Moon’s surface.  Mihaly Horanyi leads this investigation, called the Lunar Dust Experiment, aimed at understanding the purported observations of levitated dust.  This experiment was also very succes...

  18. Fluorescence lidar. [for remote sensing of environments and atmospheric constituents

    Science.gov (United States)

    Mcllrath, T. J.

    1980-01-01

    The physics of fluorescence lidar is reviewed, with emphasis placed on understanding the features which determine its applicability to particular species and environments. The successful applications of fluorescence lidar to date are covered, and a range of proposed measurements is considered. Attention is given to stratospheric applications.

  19. Availability and use of radiometric neutron monitor materials for characterizing nuclear reactor environments

    International Nuclear Information System (INIS)

    The Isotope Research Materials Laboratory (IRML) at the Oak Ridge National Laboratory routinely provides passive dosimeter materials to the research community for monitoring neutron energy, flux, and fluence. Important considerations in selecting these materials include, but are not limited to, response to specific neutron energies, encapsulation material, temperature limitation, size, reaction product half-life, amount of reaction product after irradiation, and competing reactions. Details relating to the preparation, characterization, and availability of specific passive dosimeter materials that address the consideration described above are summarized. Dosimetry used for characterizing the neutron environment in the Dounreay Prototype Fast Reactor for determining the integral cross section for a wide variety of higher actinide isotopes is described. (orig.)

  20. Atmospheric environment for Space Shuttle (STS-5) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1983-01-01

    This report presents a summary of selected atmospheric conditions observed near Space Shuttle STS-5 launch time on November 11, 1982, at Kennedy Space Center, Florida. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given in this report. Also presented are the wind and thermodynamic parameters measured at the surface and aloft in he SRB descent/impact ocean area. Final meteorological tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-5 vehicle ascent and SRB descent have been constructed. The STS-5 ascent meteorological data tape has been constructed by Marshall Space Flight Center in response to Shuttle task agreement No. 936-53-22-368 with Johnson Space Center.

  1. Atmospheric environment for Space Shuttle (STS-6) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1983-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-6 launch time on April 4, 1983, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given. Also presented are the wind and thermodynamic parameters measured at the surface and aloft in the SRB descent/impact ocean area. Final meteorological tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-6 veicle ascent and SRB descent were constructed. The STS-6 ascent meteorological data tape was constructed by Marshall Space Flight Center in response to Shuttle task agreement No. 936-53-22-368 with Johnson Space Center.

  2. Atmospheric environment for Space Shuttle (STS-7) launch

    Science.gov (United States)

    Johnson, D. L.; Hill, C. K.; Batts, G. W.

    1983-01-01

    Selected atmospheric conditions observed near Space Shuttle STS-7 launch time on June 18, 1983, at Kennedy Space Center, Florida are summarized. Values of ambient pressure, temperature, moisture, ground winds, visual observations (cloud), and winds aloft are included. The sequence of prelaunch Jimsphere measured vertical wind profiles is given in this report. Also presented are wind and thermodynamic parameters representative of surface and aloft conditions in the SRB descent/impact ocean area. Final meteorological tapes, which consist of wind and thermodynamic parameters versus altitude, for STS-7 vehicle ascent and Acoustic/SRB descent have been constructed. The STS-7 ascent meteorological data tape has been constructed by Marshall Space Flight Center in response to Shuttle task agreement No. 936-53-22-368 with Johnson Space Center.

  3. Wind and Current Intermittency in Coastal and Atmospheric Environments

    Science.gov (United States)

    Sekula, Emil; Martinez-Benjamin, Juan Jose; Redondo, Jose M.; Jorge, Juan; Mahjoub, Otman B.

    2015-04-01

    We study at several non-homogeneous sites, such as the coastal Mediterranean Area (Ebro Delta, Blanes) and in the iberian Plateau the wind intermittency as well as the fractal structure of the induced cloud and wave fronts. Weather data from 10 and 100m hight masts are used to calculate Local Richardson number, Monin-Obukhov length, eddy transfer coefficients, turbulent kinetic energy, turbulent intensities, friction velocities and sensible heat flux at three levels (5, 17 and 32 m) were considered. The results show how the stability at 17 and 32 m influences the turbulent transfer near the ground. The shear of wind or convection are the main mechanism to produce mixing in the surface, which is often detected in satellite images of nearby clouds or coastal features. The influence of internal gravity-waves on the atmospheric boundary-layer during strong stable stratification is quantified. atmospheric and oceanic circulation involve non-linear intermittency that account for unresolved turbulent mixing and diffusion. The most sophisticated turbulent closure models involve using structure functions of higher order [1,2]. The relationship between the intermittency of turbulence and the type of stratification for different atmospheric situations during the SABLES98 field campaign. We first show that the scaling behaviour of the velocity structure function in events such as GABLS (GEWEX Atmospheric Boundary-Layer Study)and in combined ESA SAR measurements [3-6] near the coast exhibit fractal and intermittent scaling. Near the Gulf of Lyons, vortical scaling show coupling between synoptic and rossby deformation scales [7]. [1]Mahjoub O., Redondo J.M. and Babiano A. (1998) Structure Functions in Complex Flows, Applied Scientific Research 59, 299-313. [2]Fraunie P., Berreba S. Chashechkin Y., Velasco D. and Redondo J.M. (2008)LES and laboratory experiments on the decay of grid wakes in strongly stratified flows. Il Nuovo Cimento C 31, 909-930. [3]Diez M., Bezerra M

  4. Sterilisation properties of the Mars surface and atmospheric environment

    Science.gov (United States)

    Moreau, D.; Muller, C.

    The radiative and chemical conditions at the surface and in the lower Martian atmosphere are computed at various latitudes and seasons combining a 2D photochemical model and radiation simulations. In most situations, the solar UV B and C radiations reach the surface however, suspended dust and, in polar cases, ozone can constitute an effective UV shield. The daytime and night time concentrations of the sterilizing oxidants: /OH, H2O2 and O3 are determined, as well as the concentration of the substances which could influence the metabolism of microorganisms. The possible habitats of a remaining Mar's life as well as the possibilities of contamination by resistant earth life forms will be described.

  5. The Shoreline Environment Atmospheric Dispersion Experiment (SEADEX): Airborne LIDAR data

    International Nuclear Information System (INIS)

    The Shoreline Environment Dispersion Experiment (SEADEX) was a major field experimental program sponsored by the US Nuclear Regulatory Commission (NRC) for the purpose of acquiring a comprehensive, high-quality data base for evaluating models of dispersion within coastal zones. A secondary objective of the program was to provide data to help determine which meteorological measurements are most appropriate for emergency preparedness at nuclear power plant sites. The first field study in this program, SEADEX-I, was conducted in the vicinity of Kewaunee, Wisconsin, on the western shore of Lake Michigan, during the period 28 May-8 June 1982. SRI International was responsible for the design and direction of the field study, as well as for the conduct of some of the measurements. The field-study design included dispersion measurements of oil-fog (aerosol) and SF6 (gas) tracers released simultaneously from the same point, as well as extensive meteorological measurements. This volume covers the airborne lidar data collected by the ALPHA-1 (Airborne Lidar Plume and Haze Analyzer) system operated on board SRI's Queen Air aircraft. The basic ALPHA-1 data consist of vertical cross sections of relative aerosol density within the oil-fog tracer plume, obtained from the down-looking lidar measurements as the aircraft flew over the plume, generally in a cross-plume direction. The vertical cross sections are made up of lidar profiles of relative aerosol obtained at the rate of 5 profiles/sec, which translates to 12 m of horizontal distance between profiles. The lidar data also include measurements of underlying terrain heights, as well as ambient boundary-layer aerosol distributions. 4 refs., 15 figs., 4 tabs

  6. FY06 LDRD Final Report "The Creation of a Neutron Star Atmosphere"

    Energy Technology Data Exchange (ETDEWEB)

    Klein, R I; Remington, B; Moon, S; MacKinnon, A; Patel, P; Ruytov, D; Wilks, S; Pape, S L

    2007-03-01

    We have taken the initiative to examine whether experiments on HED facilities, present and future, could achieve the extreme scaled conditions relevant to accreting neutron star atmospheres and accretion disks around black holes. The preliminary conclusion from this detailed scaling assessment is that if an exact scaled version of the photon bubble instability physics is desired, this will require experiments with (simultaneously) spatial scales of order {approx}1 mm, temperatures of order {approx}5 keV, magnetic fields of order a hundred megaGauss, and time scales of order several hundred psec. Aspects (subsets) of this physics can be studied under less demanding conditions. To achieve the temperatures required in targets of order several optical depths, we come to the preliminary conclusion that we would require an energy source that delivers of order of a megajoule of energy into a high Z target. A conceptual design for such an experiment could be to use the energy from a high gain ignition NIF capsule as our principle source of heating and acceleration whereby the target is in close proximity to the ignition capsule and then use external petawatt lasers to develop the magnetic fields required.

  7. Thoron (220Rn) in the indoor atmospheric environment

    International Nuclear Information System (INIS)

    Naturally occurring background radiation is a topic, which has evoked curiosity and concern between the scientist and layman alike in recent years due to the shift in focus of health effects due to exposure of radiation from acute high level to chronic low level. Many locations around the world have higher levels of natural background radiation due to elevated levels of primordial radio nuclides in the soil and their decay products like radon (222Rn), and thoron (220Rn) in the environment. Of late, technologically enhanced naturally occurring radioactive material has also contributed to the burden of background radiation. It has been estimated that inhalation of 222Rn, 220Rn and their short lived progenies contribute more than 54% of the total natural background radiation dose received by the general population. In the Indian context, in an earlier national survey, the external gamma radiation dose rates have been more or less well mapped using thermo luminescent dosimeters covering more than 214 locations, which has yielded a national average of 775 mGy/y. Of this, nearly 48.7% contribution of the dose rate is from 40K and the rest from the uranium (33.6%) and thorium (17.7%) series. A good database pertaining to the country wide levels of uranium, thorium and potassium in geological materials also exists. Thus, there exists a good database on the total external gamma radiation level across the country. Since the contribution from inhalation of 222Rn, 220Rn and their short lived progenies contributes more than 54% of the total background radiation dose, it was necessary to supplement the external component with inhalation component. This component is not adequately estimated for the country so far on national level. With this in mind, a national survey has been executed by this center involving a large number of universities and other allied research institutions from different parts of the country for the estimation of inhalation component of the dose rate

  8. The Second Sino-French Workshop on Atmospheric Environment (Orleans, December 2010):Preface

    Institute of Scientific and Technical Information of China (English)

    Abdelwahid Mellouki; Fahe Chai; Yujing Mu; Tao Wang

    2012-01-01

    A sound scientific understanding of the factors affecting the environment is essential to guarantee the sustainable development of the world's economic and societal activities.Many environmental issues,such as air quality and climate change are intimately linked to atmospheric chemistry and physics,therefore research in these areas is of tremendous importance.Both anthropogenic and biogenic emissions contribute greatly to the chemical composition of the atmosphere.Even though the atmosphere is a self-cleaning system through its photochemically-driven reactions,the hazardous direct impacts of primary and secondary pollutants on human health and ecosystems are observable and have been evidenced on different scales from local to global (e.g.ozone hole,climate change,air quality…).The chemical processing of the species present in the atmosphere is one of the most important players in driving the evolution of the atmosphere.

  9. The design of the inelastic neutron scattering mode for the Extreme Environment Diffractometer with the 26 T High Field Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Bartkowiak, Maciej, E-mail: maciej.bartkowiak@helmholtz-berlin.de; Stüßer, Norbert; Prokhnenko, Oleksandr

    2015-10-11

    The Extreme Environment Diffractometer is a neutron time-of-flight instrument, designed to work with a constant-field hybrid magnet capable of reaching fields over 26 T, unprecedented in neutron science; however, the presence of the magnet imposes both spatial and technical limitations on the surrounding instrument components. In addition to the existing diffraction and small-angle neutron scattering modes, the instrument will operate also in an inelastic scattering mode, as a direct time-of-flight spectrometer. In this paper we present the Monte Carlo ray-tracing simulations, the results of which illustrate the performance of the instrument in the inelastic-scattering mode. We describe the focussing neutron guide and the chopper system of the existing instrument and the planned design for the instrument upgrade. The neutron flux, neutron spatial distribution, divergence distribution and energy resolution are calculated for standard instrument configurations.

  10. The design of the inelastic neutron scattering mode for the Extreme Environment Diffractometer with the 26 T High Field Magnet

    International Nuclear Information System (INIS)

    The Extreme Environment Diffractometer is a neutron time-of-flight instrument, designed to work with a constant-field hybrid magnet capable of reaching fields over 26 T, unprecedented in neutron science; however, the presence of the magnet imposes both spatial and technical limitations on the surrounding instrument components. In addition to the existing diffraction and small-angle neutron scattering modes, the instrument will operate also in an inelastic scattering mode, as a direct time-of-flight spectrometer. In this paper we present the Monte Carlo ray-tracing simulations, the results of which illustrate the performance of the instrument in the inelastic-scattering mode. We describe the focussing neutron guide and the chopper system of the existing instrument and the planned design for the instrument upgrade. The neutron flux, neutron spatial distribution, divergence distribution and energy resolution are calculated for standard instrument configurations

  11. Determination of Si, Al and Fe in atmospheric particulate material by 14-MeV neutron activation analysis

    International Nuclear Information System (INIS)

    Concentrations of Si, Al and Fe were determined in atmospheric particulate material using 14 MeV neutron activation analysis, at the levels at which they normally exist. Enrichment factor and the importance of Al and Fe as being normalizing elements were discussed. Concentrations of Si, Al and Fe were found to be 20.8+-3.6, 7.20+-1.5 and 2.68 +-0.91 μg/m3 respectively

  12. Recent advances in the study of H environments and behavior in minerals using neutron powder diffraction

    Science.gov (United States)

    Welch, M. D.

    2002-12-01

    It is now possible to probe the structural environments and behavior of H atoms directly in complex minerals such as amphiboles, micas, chlorites and humites using neutron powder diffraction, in some cases as a function of pressure and/or temperature. A combination of high neutron flux and increased detector sensitivity and size offers the chance to see details of H behaviour. In the last year or so the advent of new gasket designs for the Paris-Edinburgh pressure cell allow the use of ethanol/methanol (EtOD/MeOD) as a pressure medium, removing peak broadening arising from deviatoric stress that occurs above 3 GPa for the standard fluorinert pressure medium. Essentially hydrostatic conditions obtain with EtOD/MeOD to 8 GPa at 298 K. A further recent development has been the design of a high P-T module for use with the Paris-Edinburgh cell. These technological improvements in pressure-cell design now allow us to make meaningful correlations between OH vibrational spectra collected at high P and/or T and detailed structural information on H behaviour obtained from neutron diffraction under similar conditions. In this talk I shall discuss recent neutron diffraction experiments on the effect of pressure upon hydrogen bonding in deuterated chlorite to 5 GPa (298 K), and a high P-T study of hydrogen bonding in deuterated brucite to 7 GPa, 1100 K. These two studies illustrate how far high-pressure neutron diffraction has come in the last 5 years. Finally, I shall describe a neutron powder diffraction study (ambient conditions) of leucophoenicite, Mn7Si3O12(OH)2, a close structural analogue of Phase-B and Superhydrous-B: the structure of leucophoenicite is topologically identical to the hydrous sheet of Phase-B and similar to that of Superhydrous-B. For various reasons it was not possible to deuterate the sample. Nonetheless, the two distinct H atoms were approximately located in difference-Fourier maps and then refined isotropically. The H positions in Phase-B were only

  13. Studies on radioactivity in aquatic and atmospheric environs of coastal Karnataka, Kaiga and Goa

    International Nuclear Information System (INIS)

    A systematic study on background radiation level and radionuclide distribution in the environs of coastal Karnataka, Kaiga and Goa has been initiated. In the first phase, a reliable baseline data on background radiation level and distribution of radionuclides in the terrestrial environs of coastal Karnataka and Kaiga was established. Investigations for establishing baseline data in aquatic and atmospheric environs of coastal Karnataka and terrestrial environs of Goa is now under progress. Atmospheric radon daughter concentrations, diurnal variations, seasonal variations and radon emanation rates are studied. A new approach to the model based on diffusion theory is formulated to understand 222Rn migration in soil. Experimental results are analysed on the basis of the new model and interpreted. The results of these systematic investigations are presented and discussed. (author)

  14. Space and Atmospheric Environments: From Low Earth Orbits to Deep Space

    Science.gov (United States)

    Barth, Janet L.

    2003-01-01

    Natural space and atmospheric environments pose a difficult challenge for designers of technological systems in space. The deleterious effects of environment interactions with the systems include degradation of materials, thermal changes, contamination, excitation, spacecraft glow, charging, radiation damage, and induced background interference. Design accommodations must be realistic with minimum impact on performance while maintaining a balance between cost and risk. The goal of applied research in space environments and effects is to limit environmental impacts at low cost relative to spacecraft cost and to infuse enabling and commercial off-the-shelf technologies into space programs. The need to perform applied research to understand the space environment in a practical sense and to develop methods to mitigate these environment effects is frequently underestimated by space agencies and industry. Applied science research in this area is critical because the complexity of spacecraft systems is increasing, and they are exposed simultaneously to a multitude of space environments.

  15. Sulfur isotopic composition and source identification of atmospheric environment in central Zhejiang,China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Sulfur dioxide and sulfate aerosols in the atmosphere are significant factors leading to acidification of the atmospheric environment and worsening the pollution of acid deposition. Because of the "fingerprint" characteristics of the stable sulfur isotopic composition, sulfur isotope has been widely adopted in environmental researches concerning sulfur cycle and source identification. In this study, the atmospheric environment of Jinhua City, central Zhejiang Province, was continuously monitored, and the sulfur isotopic composition of SO2 and sulfate aerosols in the atmosphere was analyzed. The results indicate that the variation of δ34S values for SO2 ranges from 1.0‰ to 7.5‰, and annual average is 4.7‰±2.3‰, whereas that of sulfate aerosols ranges from 6.4‰ to 9.8‰,and annual average is 8.1‰±1.0‰. The δ 34S values for SO2 have significant seasonal variations, which are 7.0‰ in winter and 3.3‰ in summer. These variations cannot be attributed to a single factor, and we suggest a temperature-dependent isotope equilibrium fractionation and elevated biogenic sulfur emissions of isotopically light S in summer may be the main controlling mechanisms. Furthermore, we also discuss the δ 34S model of atmospheric SO2 oxidation to form sulfate, and suggest that heterogeneous oxidation dominates in the oxidation reactions of atmospheric SO2 in the central Zhejiang Province. We further suggest that the relative humidity in the atmosphere plays an important role in the oxidation mechanism of atmospheric SO2.

  16. Measurement of neutron spectra in varied environments by the foil-activation method with arbitrary trials

    International Nuclear Information System (INIS)

    Neutron spectra have been measured by the foil-activation method in 13 different environments in and around the Sandia Pulsed Reactor, the White Sands Missile Range Fast Burst Reactor, and the Sandia Annular Core Research Reactor. The spectra were obtained by using the SANDII code in a manner that was not dependent on the initial trial. This altered technique is better suited for the determination of spectra in environments that are difficult to predict by calculation, and it tends to reveal features that may be biased out by the use of standard trial-dependent methods. For some of the configurations, studies have also been made of how well the solution is determined in each energy region. The experimental methods and the techniques used in the analyses are thoroughly explained. 34 refs., 51 figs., 40 tabs

  17. Optimization of multi-channel neutron focusing guides for extreme sample environments

    International Nuclear Information System (INIS)

    In this work, we present and discuss simulation results for the design of multichannel neutron focusing guides for extreme sample environments. A single focusing guide consists of any number of supermirror-coated curved outer channels surrounding a central channel. Furthermore, a guide is separated into two sections in order to allow for extension into a sample environment. The performance of a guide is evaluated through a Monte-Carlo ray tracing simulation which is further coupled to an optimization algorithm in order to find the best possible guide for a given situation. A number of population-based algorithms have been investigated for this purpose. These include particle-swarm optimization, artificial bee colony, and differential evolution. The performance of each algorithm and preliminary results of the design of a multi-channel neutron focusing guide using these methods are described. We found that a three-channel focusing guide offered the best performance, with a gain factor of 2.4 compared to no focusing guide, for the design scenario investigated in this work.

  18. Optimization of multi-channel neutron focusing guides for extreme sample environments

    Science.gov (United States)

    Di Julio, D. D.; Lelièvre-Berna, E.; Courtois, P.; Andersen, K. H.; Bentley, P. M.

    2014-07-01

    In this work, we present and discuss simulation results for the design of multichannel neutron focusing guides for extreme sample environments. A single focusing guide consists of any number of supermirror-coated curved outer channels surrounding a central channel. Furthermore, a guide is separated into two sections in order to allow for extension into a sample environment. The performance of a guide is evaluated through a Monte-Carlo ray tracing simulation which is further coupled to an optimization algorithm in order to find the best possible guide for a given situation. A number of population-based algorithms have been investigated for this purpose. These include particle-swarm optimization, artificial bee colony, and differential evolution. The performance of each algorithm and preliminary results of the design of a multi-channel neutron focusing guide using these methods are described. We found that a three-channel focusing guide offered the best performance, with a gain factor of 2.4 compared to no focusing guide, for the design scenario investigated in this work.

  19. Comm for Small Sats: The Lunar Atmosphere and Dust Environment Explorer (LADEE) Communications Subsystem

    Science.gov (United States)

    Kuroda, Vanessa M.; Allard, Mark R.; Lewis, Brian; Lindsay, Michael

    2014-01-01

    September 6, 2013 through April 21, 2014 marked the mission lifecycle of the highly successful LADEE (Lunar Atmosphere and Dust Environment Explorer) mission that orbited the moon to gather detailed information about the thin lunar atmosphere. This paper will address the development, risks, and lessons learned regarding the specification, selection, and deployment of LADEE's unique Radio Frequency based communications subsystem and supporting tools. This includes the Electronic Ground Support Equipment (EGSE), test regimes, and RF dynamic link analysis environment developed to meet mission requirements for small, flexible, low cost, high performance, fast turnaround, and reusable spacecraft communication capabilities with easy and reliable application to future similar low cost small satellite missions over widely varying needs for communications and communications system complexity. LADEE communication subsystem key components, architecture, and mission performance will be reviewed toward applicability for future mission planning, design, and utilization.

  20. VISSR Atmospheric Sounder (VAS) simulation experiment for a severe storm environment

    Science.gov (United States)

    Chesters, D.; Uccellini, L. W.; Mostek, A.

    1981-01-01

    Radiance fields were simulated for prethunderstorm environments in Oklahoma to demonstrate three points: (1) significant moisture gradients can be seen directly in images of the VISSIR Atmospheric Sounder (VAS) channels; (2) temperature and moisture profiles can be retrieved from VAS radiances with sufficient accuracy to be useful for mesoscale analysis of a severe storm environment; and (3) the quality of VAS mesoscale soundings improves with conditioning by local weather statistics. The results represent the optimum retrievability of mesoscale information from VAS radiance without the use of ancillary data. The simulations suggest that VAS data will yield the best soundings when a human being classifies the scene, picks relatively clear areas for retrieval, and applies a "local" statistical data base to resolve the ambiguities of satellite observations in favor of the most probable atmospheric structure.

  1. Application of numerical environment system to regional atmospheric radioactivity transport simulations

    International Nuclear Information System (INIS)

    Main functions of the Numerical Environment System (NES), as a part of the Information Technology Based Laboratory (ITBL) project implemented by Japan Atomic Energy Research Institute, became available for test use purposes although the development of the system is still underway. This system consists of numerical models of meteorology and atmospheric dispersion, database necessary for model simulations, post- and pre-processors such as data conversion and visualization, and a suite of system software which provide the users with system functions through a web page access. The system utilizes calculation servers such as vector- and scalar-parallel processors for numerical model execution, a EWS which serves as a hub of the system. This system provides users in the field of nuclear emergency preparedness and atmospheric environment with easy-to-use functions of atmospheric dispersion simulations including input meteorological data preparation and visualization of simulation results. The performance of numerical models in the system was examined with observation data of long-range transported radon-222. The models in the system reproduced quite well temporal variations in the observed radon-222 concentrations in air which were caused by changes in the meteorological field in the synoptic scale. By applying the NES models in combination with the idea of backward-in-time atmospheric dispersion simulation, seasonal shift of source areas of radon-222 in the eastern Asian regions affecting the concentrations in Japan was quantitatively illustrated. (authors)

  2. Atmospheric Corrosion Behavior of 2A12 Aluminum Alloy in a Tropical Marine Environment

    OpenAIRE

    Zhongyu Cui; Xiaogang Li; Huan Zhang; Kui Xiao; Chaofang Dong; Zhiyong Liu; Liwei Wang

    2015-01-01

    Atmospheric corrosion behavior of 2A12 aluminum alloy exposed to a tropical marine environment for 4 years was investigated. Weight loss of 2A12 alloy in the log-log coordinates can be well fitted with two linear segments, attributing to the evolution of the corrosion products. EIS results indicate that the corrosion product layer formed on the specimens exposed for 12 months or longer presents a good barrier effect. Corrosion morphology changes from pitting corrosion to severe intergranular ...

  3. Demonstrating the Operational Value of Atmospheric Infrared Sounder (AIRS) Profiles in the Pre-Convective Environment

    Science.gov (United States)

    Kozlowski, Danielle; Zavodsky, Bradley; Stano, Geoffrey; Jedlovec, Gary

    2011-01-01

    The Short-term Prediction Research and Transition (SPoRT) is a project to transition those NASA observations and research capabilities to the weather forecasting community to improve the short-term regional forecasts. This poster reviews the work to demonstrate the value to these forecasts of profiles from the Atmospheric Infrared Sounder (AIRS) instrument on board the Aqua satellite with particular assistance in predicting thunderstorm forecasts by the profiles of the pre-convective environment.

  4. Effect of temperature and atmospheric environment on the photodegradation of some Disperse Red 1 type polymers

    OpenAIRE

    Galvan-Gonzalez, Adriana; Canva, Michael; Stegeman, George I.; Twieg, Robert; Kowalczyk, Tony C.; Lackritz, Hilary S.

    1999-01-01

    The photodegradation of the azobenzene chromophore DR1 {4-[N-ethyl-N-(2-hydroxyethyl)amino]-4'- nitroazobenzene]} incorporated as a side chain or as a guest in a poly(methyl) methacrylate host has been evaluated as a function of wavelength, temperature, and the atmospheric environment. The effects of these variables on the lifetime of DR1-based electro-optic devices is quantified

  5. Impact of Urban Surface Roughness Length Parameterization Scheme on Urban Atmospheric Environment Simulation

    OpenAIRE

    Meichun Cao; Zhaohui Lin

    2014-01-01

    In this paper, the impact of urban surface roughness length $({z}_{0})$ parameterization scheme on the atmospheric environment simulation over Beijing has been investigated through two sets of numerical experiments using the Weather Research and Forecasting model coupled with the Urban Canopy Model. For the control experiment (CTL), the urban surface ${z}_{0}$ parameterization scheme used in UCM is the model default one. For another experiment (EXP), a newly developed urban surface ${z}_{0}$ ...

  6. Radiation exposure of airline crew members to the atmospheric ionizing radiation environment

    International Nuclear Information System (INIS)

    A study of radiation exposures in the ionizing radiation environment of the atmosphere is currently in progress for the Italian civil aviation flight personnel. After a description of the considered data sources/ the philosophy of the study is presented/ and an overview is given of the data processing with regard to flight routes/ the computational techniques for radiation dose evaluation along the flight paths and for the exposure matrix building/ along with an indication of the results that the study should provide.

  7. Gas and aerosol radionuclide transfers in complex environments: experimental studies of atmospheric dispersion and interfaces exchanges

    International Nuclear Information System (INIS)

    In situations of chronic or accidental releases, the atmosphere is the main pathway of radioactive releases from nuclear facilities to the environment and, consequently, to humans. It is therefore necessary to have sufficient information on this pathway to accurately assess the radiological impact on man and his environment. Institute for Radioprotection and Nuclear Safety develops its own tools of dispersion and atmospheric transfer for its expertise, under normal operation conditions of a facility, but especially in crisis or post-accident. These tools must have a national and international recognition in particular through scientific validation against benchmark experiments performed internationally, nationally or within the IRSN. The Radioecology Laboratory of Cherbourg-Octeville provides, and will increasingly make, a significant contribution to the scientific influence of the Institute in this field. The work presented in this report has contributed to the development or improvement of experimental techniques in the fields of atmospheric dispersion of radionuclides and transfer at interfaces, in complex environments (complex topography, urban area). These experimental techniques, applied during field campaigns, have allowed to acquire new data in order to get a better understanding of radionuclide transfers in the form of gases and aerosols. (author)

  8. Atmospheric corrosion resistance of MnCuP weathering steel in simulated environments

    International Nuclear Information System (INIS)

    Highlights: → Atmospheric corrosion resistance of a low cost MnCuP weathering steel was investigated by simulated wet/dry cyclic tests. → The steel shows high corrosion resistance in simulated coastal, industrial, and coastal-industrial atmospheres. → Mn and Cu are identified in bivalent and univalent respectively, leading to cation-selectivity of the rust layer. → Phosphorus promotes the formation of non-soluble phosphates that may act as corrosion inhibitor in rust layer. - Abstract: In this work, atmospheric corrosion resistance of low cost MnCuP weathering steel in simulated coastal, industrial, and coastal-industrial atmospheric environments was investigated by wet/dry cyclic acceleration corrosion tests. The results indicate that MnCuP weathering steel exhibits high corrosion resistance in the three atmospheres. Besides, the alloying effect of Mn, Cu, and P elements on the anti-corrosion mechanism of MnCuP weathering steel was discussed by techniques of X-ray photoelectron spectroscopy, potential-pH diagram, and electron probe microanalysis.

  9. Measurement result of the neutron monitor onboard Space Environment Data Acquisition Equipment - Attached Payload (SEDA-AP)

    Science.gov (United States)

    Koga, K.; Matsumoto, H.; Okudaira, O.; Obara, T.; Yamamoto, T.; Muraki, Y.

    2011-12-01

    To support future space activities, it is very important to acquire the space environmental data which causes the degradation of space parts and spacecraft anomalies. Such data are useful for spacecraft design and manned space activity. Space Environment Data Acquisition - Attached Payload (SEDA-AP) measures the space environment around the International Space Station (ISS) by being attached to the Exposed Facility(EF) of the Japanese Experimental Module ("Kibo"). The Neutron Monitor (NEM) is one of the detectors in SEDA-AP. This instrument was developed to measure the solar neutrons which are produced by solar flare event. The solar neutron is a good indicator to clarify the acceleration mechanism of charged particles at the solar flare. Because of the energy of solar neutron is not influenced by the interplanetary magnetic field, it has the information of the energy of the accelerated charged particle directly. We have been analyzing the neutron data at several M or X class solar flare from September 2009. The mission objectives, instrumentation and measurement status of the neutron monitor are reported.

  10. On the Integration of a Readout System Dedicated for Neutron Discrimination in Harsh Environment

    Directory of Open Access Journals (Sweden)

    Krit S. Ben

    2016-01-01

    Full Text Available New insights related to the integration of a readout system dedicated for the detection and discrimination of neutrons are presented here. This study takes place in the framework of the I_SMART European project. This system will have to work later in a harsh environment in terms of temperature and radiations, what makes not only the development of specifications for operation and reliability of the components necessary but also the investigation of margins for the interplay of the system. Implementation of the analog conditioning chain at transistor level (AMS (Analog/Mixed Signal 0.35μm CMOS technology is investigated here where electrical performances have been validated at SPICE-level simulations using “Spectre” simulator (SPICE-based under Cadence DFII.

  11. Exposure to the atmospheric ionizing radiation environment: a study on Italian civilian aviation flight personnel

    International Nuclear Information System (INIS)

    A study of the effects of high-LET, low-dose and low-dose-rate ionizing radiation and associated risk analysis is underway. This study involves analyzing the atmospheric ionizing radiation exposure (including high-energy neutrons) and associated effects for members of civilian aviation flight personnel, in an attempt to better understand low-dose long-term radiation effects on human subjects. The study population includes all Italian civilian airline flight personnel, both cockpit and cabin crew members, whose work history records and actual flights (route, aircraft type, and date for each individual flight for each person where possible) are available. The dose calculations are performed along specific flight legs, taking into account the actual flight profiles for all different routes and the variations with time of solar and geomagnetic parameters. Dose values for each flight are applied to the flight history of study participants in order to estimate the individual annual and lifetime occupational radiation dose. An update of the study of the physical atmospheric ionizing radiation exposure is given here, in terms of environmental modeling, flight routes, radiation dose evaluation along different flight paths, and exposure matrix construction. The exposure analysis is still in progress, and the first results are expected soon

  12. The Neutral Mass Spectrometer on the Lunar Atmosphere and Dust Environment Explorer Mission

    Science.gov (United States)

    Mahaffy, Paul R.; Richard Hodges, R.; Benna, Mehdi; King, Todd; Arvey, Robert; Barciniak, Michael; Bendt, Mirl; Carigan, Daniel; Errigo, Therese; Harpold, Daniel N.; Holmes, Vincent; Johnson, Christopher S.; Kellogg, James; Kimvilakani, Patrick; Lefavor, Matthew; Hengemihle, Jerome; Jaeger, Ferzan; Lyness, Eric; Maurer, John; Nguyen, Daniel; Nolan, Thomas J.; Noreiga, Felix; Noriega, Marvin; Patel, Kiran; Prats, Benito; Quinones, Omar; Raaen, Eric; Tan, Florence; Weidner, Edwin; Woronowicz, Michael; Gundersen, Cynthia; Battel, Steven; Block, Bruce P.; Arnett, Ken; Miller, Ryan; Cooper, Curt; Edmonson, Charles

    2014-12-01

    The Neutral Mass Spectrometer (NMS) of the Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission is designed to measure the composition and variability of the tenuous lunar atmosphere. The NMS complements two other instruments on the LADEE spacecraft designed to secure spectroscopic measurements of lunar composition and in situ measurement of lunar dust over the course of a 100-day mission in order to sample multiple lunation periods. The NMS utilizes a dual ion source designed to measure both surface reactive and inert species and a quadrupole analyzer. The NMS is expected to secure time resolved measurements of helium and argon and determine abundance or upper limits for many other species either sputtered or thermally evolved from the lunar surface.

  13. The Neutral Mass Spectrometer on the Lunar Atmosphere and Dust Environment Explorer Mission

    Science.gov (United States)

    Mahaffy, Paul R.; Hodges, R. Richard; Benna, Mehdi; King, Todd; Arvey, Robert; Barciniak, Michael; Bendt, Mirl; Carigan, Daniel; Errigo, Therese; Harpold, Daniel N.; Holmes, Vincent; Johnson, Christopher S.; Kellogg, James; Kimvilakani, Patrick; Lefavor, Matthew; Hengemihle, Jerome; Jaeger, Ferzan; Lyness, Eric; Maurer, John; Nguyen, Daniel; Nolan, Thomas; Noreiga, Felix; Noreiga, Marvin; Patel, Kiran; Prats, Benito; Quinones, Omar; Raaen, Eric; Tan, Florence; Weidner, Edwin; Woronowicz, Michael; Gundersen, Cynthia (Inventor); Battel, Steven; Block, Bruce P.; Arnett, Ken; Miller, Ryan

    2014-01-01

    The Neutral Mass Spectrometer (NMS) of the Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission is designed to measure the composition and variability of the tenuous lunar atmosphere. The NMS complements two other instruments on the LADEE spacecraft designed to secure spectroscopic measurements of lunar composition and in situ measurement of lunar dust over the course of a 100-day mission in order to sample multiple lunation periods. The NMS utilizes a dual ion source designed to measure both surface reactive and inert species and a quadrupole analyzer. The NMS is expected to secure time resolved measurements of helium and argon and determine abundance or upper limits for many other species either sputtered or thermally evolved from the lunar surface.

  14. Atmospheric electric field measurements in urban environment and the pollutant aerosol weekly dependence

    OpenAIRE

    Silva, Hugo; Conceição, Ricardo; Melgão, Marta; Nicoll, Keri; Mendes, P. B.; M. Tlemçani; Reis, A. Heitor; Harrison, R. G.

    2014-01-01

    The weekly dependence of pollutant aerosols in the urban environment of Lisbon (Portugal) is inferred from the records of atmospheric electric field at Portela meteorological station (38°47′N, 9°08′W). Measurements were made with a Bendorf electrograph. The data set exists from 1955 to 1990, but due to the contaminating effect of the radioactive fallout during 1960 and 1970s, only the period between 1980 and 1990 is considered here. Using a relative difference method a weekly d...

  15. Atmospheric Corrosion Behavior of 2A12 Aluminum Alloy in a Tropical Marine Environment

    Directory of Open Access Journals (Sweden)

    Zhongyu Cui

    2015-01-01

    Full Text Available Atmospheric corrosion behavior of 2A12 aluminum alloy exposed to a tropical marine environment for 4 years was investigated. Weight loss of 2A12 alloy in the log-log coordinates can be well fitted with two linear segments, attributing to the evolution of the corrosion products. EIS results indicate that the corrosion product layer formed on the specimens exposed for 12 months or longer presents a good barrier effect. Corrosion morphology changes from pitting corrosion to severe intergranular corrosion with the extension of exposure time, resulting in the reduction of the mechanical properties.

  16. Phase space representation of neutron monitor count rate and atmospheric electric field in relation to solar activity in cycles 21 and 22

    Science.gov (United States)

    Silva, H. G.; Lopes, I.

    2016-07-01

    Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

  17. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    OpenAIRE

    F. Meier; D. Scherer; Richters, J.; A. Christen

    2010-01-01

    This research quantifies and discusses atmospheric effects that alter the radiance observed by a ground-based thermal-infrared (TIR) camera mounted on top of a high-rise building in the city of Berlin, Germany. The study shows that atmospheric correction of ground-based TIR imagery of the three-dimensional (3-D) urban environment acquired in oblique viewing geometry has to account for spatial variability of line-of-sight (LOS) geometry. We present an atmospheric correction procedure t...

  18. Simultaneous atmospheric measurements using two Fourier transform infrared spectrometers at the Polar Environment Atmospheric Research Laboratory during spring 2006, and comparisons with the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer

    OpenAIRE

    D. Fu; K. A. Walker; R. L. Mittermeier; Strong, K.; Sung, K.; H. Fast; Bernath, P. F.; C. D. Boone; W. H. Daffer; Fogal, P.; Kolonjari, F.; P. Loewen; Manney, G. L.; O. Mikhailov

    2008-01-01

    The 2006 Canadian Arctic ACE (Atmospheric Chemistry Experiment) Validation Campaign collected measurements at the Polar Environment Atmospheric Research Laboratory (PEARL, 80.05° N, 86.42° W, 610 m above sea level) at Eureka, Canada from 17 February to 31 March 2006. Two of the ten instruments involved in the campaign, both Fourier transform spectrometers (FTSs), were operated simultaneously, recording atmospheric solar absorption spectra. The first instrument was an ABB Bomem...

  19. Characterization of Atmospheric Corrosion of 2A12 Aluminum Alloy in Tropical Marine Environment

    Science.gov (United States)

    Li, T.; Li, X. G.; Dong, C. F.; Cheng, Y. F.

    2010-06-01

    In this work, corrosion product formed on 2A12 aluminum (Al) alloy after 3 months of natural exposure in South China Sea atmosphere was characterized by various surface analysis techniques, including scanning electron microscopy, energy-dispersive x-ray analysis, x-ray photoelectron spectroscopy, and x-ray diffraction. The atmospheric corrosion mechanism of Al alloy in marine environment was derived. Results demonstrated that Al alloy specimen experiences serious general corrosion and pitting corrosion. Al and O are enriched in the product film, and Ca and Cl are also found in the film and corrosion pits in Al alloy substrate. The main component compounds existing in the film include Al2O3, Al(OH)3, and AlOOH while AlCl3 and CaCO3 are also identified. Al alloy encounters corrosion under tropical marine atmosphere. Although somewhat protective, the formed surface film on Al alloy specimen is attacked by chloride ions, resulting in significant pitting corrosion of Al alloy.

  20. Aviation Trends Related to Atmospheric Environment Safety Technologies Project Technical Challenges

    Science.gov (United States)

    Reveley, Mary S.; Withrow, Colleen A.; Barr, Lawrence C.; Evans, Joni K.; Leone, Karen M.; Jones, Sharon M.

    2014-01-01

    Current and future aviation safety trends related to the National Aeronautics and Space Administration's Atmospheric Environment Safety Technologies Project's three technical challenges (engine icing characterization and simulation capability; airframe icing simulation and engineering tool capability; and atmospheric hazard sensing and mitigation technology capability) were assessed by examining the National Transportation Safety Board (NTSB) accident database (1989 to 2008), incidents from the Federal Aviation Administration (FAA) accident/incident database (1989 to 2006), and literature from various industry and government sources. The accident and incident data were examined for events involving fixed-wing airplanes operating under Federal Aviation Regulation (FAR) Parts 121, 135, and 91 for atmospheric conditions related to airframe icing, ice-crystal engine icing, turbulence, clear air turbulence, wake vortex, lightning, and low visibility (fog, low ceiling, clouds, precipitation, and low lighting). Five future aviation safety risk areas associated with the three AEST technical challenges were identified after an exhaustive survey of a variety of sources and include: approach and landing accident reduction, icing/ice detection, loss of control in flight, super density operations, and runway safety.

  1. Coupled modeling system for prediction of radioactive material transport in the atmospheric, terrestrial, and oceanic environment

    International Nuclear Information System (INIS)

    A coupling numerical modeling system named SPEEDI-MP has been developed to simulate the complicated transfer process of radioactive materials in the environment. The coupled model for regional water and material cycles consists of the seven models: the non-hydrostatic atmospheric dynamic model (MM5), detailed multi-layer land surface model (SOLVEG) and three-dimensional hydrology model (RIVERS), the third-generation ocean wind-wave model (WW3), the Princeton Ocean Model (POM), and Lagrangian particle dispersion models for the atmosphere (GEARM) and ocean (SEA-GEARN). By using a general-purpose model coupling program, the above models were integrated to simulate regional water and material transports. Test calculations were carried out under a hypothetical release of the tritiated water vapor to the atmosphere in the river basin of Ibaraki in Japan to investigate the effects of rainfall, runoff, and re-emission processes on the deposition pattern. The SPEEDI-MP overall reproduced the rainfall and river flow which play an important role in the material cycle. The result showed that the deposited tritiated water vapor at the ground after the heavy rainfall event because the surface runoff increased in the river basin. Both processes of surface runoff and re-emission of the deposited tritiated water vapor in SPEEDI-MP significantly expanded the contaminated areas. (author)

  2. Visible and infrared extinction of atmospheric aerosol in the marine and coastal environment.

    Science.gov (United States)

    Kaloshin, Gennady A

    2011-05-10

    The microphysical model Marine Aerosol Extinction Profiles (MaexPro) for surface layer marine and coastal atmospheric aerosols, which is based on long-term observations of size distributions for 0.01-100 μm particles, is presented. The fundamental feature of the model is a parameterization of amplitudes and widths for aerosol modes of the aerosol size distribution function (ASDF) as functions of fetch and wind speed. The shape of the ASDF and its dependence on meteorological parameters, altitudes above the sea level (H), fetch (X), wind speed (U), and relative humidity is investigated. The model is primarily to characterize aerosols for the near-surface layer (within 25 m). The model is also applicable to higher altitudes within the atmospheric boundary layer, where the change in the vertical profile of aerosol is not very large. In this case, it is only valid for "clean" marine environments, in the absence of air pollution or any other major sources of continental aerosols, such desert dust or smoke from biomass burning. The spectral profiles of the aerosol extinction coefficients calculated by MaexPro are in good agreement with observational data and the numerical results obtained by the well-known Navy Aerosol Model and Advanced Navy Aerosol Model codes. Moreover, MaexPro was found to be an accurate and reliable instrument for investigation of the optical properties of atmospheric aerosols. PMID:21556113

  3. The System of the Calibration for Visibility Measurement Instrument Under the Atmospheric Aerosol Simulation Environment

    Directory of Open Access Journals (Sweden)

    Shu Zhifeng

    2016-01-01

    formula, then it been divided by 3 is MOR. The aerosol concentration in chamber can be changed by adjusting aerosol generator that producing variety of visibility atmospherical environment. The experiment has been carried out and the measurement accuracy of atmospheric transmittance is 0.3‰ Corresponding to the accuracy of MOR 4.9% at the 2km visibility environment. So this system can be calibrated and validated the other visibility measuring devices.

  4. The System of the Calibration for Visibility Measurement Instrument Under the Atmospheric Aerosol Simulation Environment

    Science.gov (United States)

    Shu, Zhifeng; Yang, ShaoChen; Xu, Wenjing

    2016-06-01

    divided by 3 is MOR. The aerosol concentration in chamber can be changed by adjusting aerosol generator that producing variety of visibility atmospherical environment. The experiment has been carried out and the measurement accuracy of atmospheric transmittance is 0.3‰ Corresponding to the accuracy of MOR 4.9% at the 2km visibility environment. So this system can be calibrated and validated the other visibility measuring devices.

  5. Atmospheric/Space Environment Support Lessons Learned Regarding Aerospace Vehicle Design and Operations

    Science.gov (United States)

    Vaughan, William W.; Anderson, B. Jeffrey

    2005-01-01

    In modern government and aerospace industry institutions the necessity of controlling current year costs often leads to high mobility in the technical workforce, "one-deep" technical capabilities, and minimal mentoring for young engineers. Thus, formal recording, use, and teaching of lessons learned are especially important in the maintenance and improvement of current knowledge and development of new technologies, regardless of the discipline area. Within the NASA Technical Standards Program Website http://standards.nasa.gov there is a menu item entitled "Lessons Learned/Best Practices". It contains links to a large number of engineering and technical disciplines related data sets that contain a wealth of lessons learned information based on past experiences. This paper has provided a small sample of lessons learned relative to the atmospheric and space environment. There are many more whose subsequent applications have improved our knowledge of the atmosphere and space environment, and the application of this knowledge to the engineering and operations for a variety of aerospace programs.

  6. Neutral Mass Spectrometer (NMS) for the Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission

    Science.gov (United States)

    Collier, Michael R.; Mahaffy, Paul R.; Benna, Mehdi; King, Todd T.; Hodges, Richard

    2011-01-01

    The Lunar Atmosphere and Dust Environment Explorer (LADEE) mission currently scheduled for launch in early 2013 aboard a Minotaur V will orbit the moon at a nominal periselene of 50 km to characterized the lunar atmosphere and dust environment. The science instrument payload includes a neutral mass spectrometer as well as an ultraviolet spectrometer and a dust detector. Although to date only He, Ar-40, K, Na and Rn-222 have been firmly identified in the lunar exosphere and arise from the solar wind (He), the lunar regolith (K and Na) and the lunar interior (Ar-40, Rn-222), upper limits have been set for a large number of other species, LADEE Neutral Mass Spectrometer (NMS) observations will determine the abundance of several species and substantially lower the present upper limits for many others. Additionally, LADEE NMS will observe the spatial distribution and temporal variability of species which condense at nighttime and show peak concentrations at the dawn terminator (e,g, Ar-40), possible episodic release from the lunar interior, and the results of sputtering or desorption processes from the regolith. In this presentation, we describe the LADEE NMS hardware and the anticipated science results.

  7. Source identification of PCDD/Fs for various atmospheric environments in a highly industrialized city.

    Science.gov (United States)

    Lee, Wei-Shan; Chang-Chien, Guo-Ping; Wang, Lin-Chi; Lee, Wen-Jhy; Tsai, Perng-Jy; Wu, Kuen-Yuh; Lin, Chieh

    2004-10-01

    This study set out to identify possible PCDD/F emission sources for different atmospheric environments in a highly industrialized city located in southern Taiwan. We collected stack flue gas samples from five main stationary emission sources of the municipal solid waste incinerators (MSWIs), medical waste incinerators (MWIs), electric arc furnaces (EAFs), secondary aluminum smelters (ALSs), and sinter plants to assess the characteristics of their PCDD/F emissions. For mobile sources, congener profiles reported in U.S. EPA's database for unleaded gas-fueled vehicles (UGFV) and diesel-fueled vehicles (DFV) were directly adopted owing to lack of local data. The congener profiles of the 2,3,7,8-substituted PCDD/Fs were selected as the signatures of these PCDD/F emission sources. We conducted PCDD/F samplings on atmospheric environments of four categories, including background, residential area, traffic area, and industrial area. Through PCA and cluster analyses, we found that traffic areas were most influenced by PCDD/F emissions from UGFV and DFV, while those of industrial areas were mainly influenced by metallurgical facilities and MWIs. The above results were further examined by using the methodology of the indicatory PCDD/Fs. We confirmed that traffic areas were contributed by traffic sources, but industrial areas were simply affected by metallurgical facilities rather than MWIs. In conclusion, besides the use of PCA and cluster analyses, the methodology of the indicatory PCDD/Fs should be conducted for further validation in order to prevent misjudgment. PMID:15506183

  8. Assessment of Atmospheric heavy metal deposition in North Egypt aerosols using neutron activation analysis and optical emission inductively coupled plasma

    International Nuclear Information System (INIS)

    The aim of the present study is to assess the current level of atmospheric heavy metal pollution of aerosols in different cities of North Egypt using the neutron activation analysis and optical emission inductively coupled plasma techniques. The results revealed that the highest concentrations of particulate matter PM10 and total suspended particulate matter were close to industrial areas. From the results of the enrichment factor calculations, the most significant elements of anthropogenic origin are Ba, Sb, Ce and Zn. - Highlights: → Average concentration of Cd using OE-ICP is below detection limit for all the samples. → Maximum average concentration of Pb in PM10 and TSP is 5425 and 570.3, respectively. → Concentration of 20 elements in PM10 and TSP aerosols are determined using the NAA. → EF revealed that Pb, Ba, Br, Ce, Hf, La Sb and Zn are of anthropogenic origin.

  9. Assessment of Atmospheric heavy metal deposition in North Egypt aerosols using neutron activation analysis and optical emission inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    El-Araby, E.H., E-mail: elaraby_20032000@yahoo.com [Faculty of Science, Physics Department, Jezan University, KSA (Saudi Arabia); Abd El-Wahab, M., E-mail: wahab_magda@yahoo.com [Faculty of women for Arts, Science and Education, Physics Department, Ain Shams University, PO11757 Cairo (Egypt); Diab, H.M., E-mail: hnndiab@yahoo.co.uk [National Center of Nuclear Safety and Radiation Control, Atomic Energy Authority Cairo (Egypt); El-Desouky, T.M., E-mail: trkhegazy@yahoo.com [Faculty of women for Arts, Science and Education, Physics Department, Ain Shams University, PO11757 Cairo (Egypt); Mohsen, M., E-mail: m1mohsen@yahoo.com [Faculty of Science. Physics Department, Ain-Shams University, PO 11566 Cairo (Egypt)

    2011-10-15

    The aim of the present study is to assess the current level of atmospheric heavy metal pollution of aerosols in different cities of North Egypt using the neutron activation analysis and optical emission inductively coupled plasma techniques. The results revealed that the highest concentrations of particulate matter PM{sub 10} and total suspended particulate matter were close to industrial areas. From the results of the enrichment factor calculations, the most significant elements of anthropogenic origin are Ba, Sb, Ce and Zn. - Highlights: > Average concentration of Cd using OE-ICP is below detection limit for all the samples. > Maximum average concentration of Pb in PM10 and TSP is 5425 and 570.3, respectively. > Concentration of 20 elements in PM{sub 10} and TSP aerosols are determined using the NAA. > EF revealed that Pb, Ba, Br, Ce, Hf, La Sb and Zn are of anthropogenic origin.

  10. Atmospheric deposition of heavy metals studied by analysis of moss samples using neutron activation analysis and atomic absorption spectrometry

    International Nuclear Information System (INIS)

    In a study of the atmospheric deposition of trace elements in different parts of Norway samples of the moss Hylocomium splendens were analyzed with respect to 26 elements. The determination of Cu, Zn, Pb, Cd and Ni was carried out by flame atomic absorption spectrometry, while an additional 21 elements were determined by instrumental neutron activation analysis. Several elements showed a substantially higher deposition in the southernmost parts of Norway than in places located farther north. As regards Pb, As and Sb, the difference amounted to a factor of ten or more. A similar but less pronounced trend was evident for elements such as V, Zn, Cd, Se and Ag. In some cases local pollution sources or marine aerosols had a significant effect on the results. For several heavy metals however long-distance transport from areas to the south and the south west of Norway was responsible for a major part of the air pollution

  11. Advanced sample environments for in situ neutron diffraction studies of nuclear materials

    Science.gov (United States)

    Reiche, Helmut Matthias

    Generation IV nuclear reactor concepts, such as the supercritical-water-cooled nuclear reactor (SCWR), are actively researched internationally. Operating conditions above the critical point of water (374°C, 22.1 MPa) and fuel core temperature that potentially exceed 1850°C put a high demand on the surrounding materials. For their safe application, it is essential to characterize and understand the material properties on an atomic scale such as crystal structure and grain orientation (texture) changes as a function of temperature and stress. This permits the refinement of models predicting the macroscopic behavior of the material. Neutron diffraction is a powerful tool in characterizing such crystallographic properties due to their deep penetration depth into condensed matter. This leads to the ability to study bulk material properties, as opposed to surface effects, and allows for complex sample environments to study e.g. the individual contributions of thermo-mechanical processing steps during manufacturing, operating or accident scenarios. I present three sample environments for in situ neutron diffraction studies that provide such crystallographic information and have been successfully commissioned and integrated into the user program of the High Pressure -- Preferred Orientation (HIPPO) diffractometer at the Los Alamos Neutron Science Center (LANSCE) user facility. I adapted a sample changer for reliable and fast automated texture measurements of multiple specimens. I built a creep furnace combining a 2700 N load frame with a resistive vanadium furnace, capable of temperatures up to 1000°C, and manipulated by a pair of synchronized rotation stages. This combination allows following deformation and temperature dependent texture and strain evolutions in situ. Utilizing the presented sample changer and creep furnace we studied pressure tubes made of Zr-2.5wt%Nb currently employed in CANDURTM nuclear reactors and proposed for future SCWRs, acting as the primary

  12. Atmospheric Deposition of Heavy Metals in Serbia Studied by Moss Biomonitoring, Neutron Activation Analysis and GIS Technology

    CERN Document Server

    Frontasyeva, M V; Kumar, M; Matavuly, M; Pavlov, S S; Radnovic, D; Steinnes, E

    2002-01-01

    The results of a pilot study on atmospheric deposition of heavy metals and other trace elements using the moss biomonitoring technique in the northern part of Serbia and some areas of Bosnia are presented. Samples of Hypnum cupressiforme along with some other moss types were collected at 92 sites during the summer of 2000. A total of 44 elements were determined by instrumental neutron activation analysis using epithermal neutrons. The observed levels of Cu, Zn, As, Ag, Cd, In, Sb, etc. in the area surrounding the town of Bor (Serbia) are comparable to those reported from similar industrial areas in other countries such as the Copper Basin in Poland and the South Urals of Russia. In the same region the maximum Se and Mo concentrations are the highest ever recorded in biomonitoring studies using mosses. High median concentrations of Fe and Ni in Serbian mosses are associated with a crustal component as apparent from factor analysis of the moss data. This component could be a result of windblown soil dust (most ...

  13. Behavior of structural and target materials irradiated in spallation neutron environments

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, J.F. [Univ. of Illinois, Urbana, IL (United States). Dept. of Nuclear Engineering; Wechsler, M. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Nuclear Engineering; Borden, M.; Sommer, W.F. [Los Alamos National Lab., NM (United States)

    1995-05-01

    This paper describes considerations for selection of structural and target materials for accelerator-driven neutron sources. Due to the operating constraints of proposed accelerator-driven neutron sources, the criteria for selection are different than those commonly applied to fission and fusion systems. Established irradiation performance of various alloy systems is taken into account in the selection criteria. Nevertheless, only limited materials performance data are available which specifically related to neutron energy spectra anticipated for spallation sources.

  14. Neutron Stars as a Source of the Short-Lived Nuclides in Ap-star Atmospheres

    International Nuclear Information System (INIS)

    We propose a new explanation of some magnetic chemically peculiar (MCP) star anomalies, which is based on an assumption that such stars be the close binary systems with a secondary component being a neutron star. Within this hypothesis one can naturally explain the main anomalous features of MCP stars: first of all, an existence of the short-lived radioactive isotopes detected in some stars (like Przybylski's star (PS) and HR465), and some others peculiarities. Also we can assume the presence of the electron-positron annihilation emission lines (0.511 MeV) in the gamma spectrum of some MCP stars

  15. Standard Practice for Application of CaF2(Mn) Thermoluminescence Dosimeters in Mixed Neutron-Photon Environments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This practice describes a procedure for measuring gamma-ray absorbed dose in CaF2(Mn) thermoluminescence dosimeters (TLDs) exposed to mixed neutron-photon environments during irradiation of materials and devices. The practice has broad application, but is primarily intended for use in the radiation-hardness testing of electronics. The practice is applicable to the measurement of absorbed dose from gamma radiation present in fields used for neutron testing. 1.2 This practice describes a procedure for correcting for the neutron response of a CaF2(Mn) TLD. The neutron response may be subtracted from the total response to give the gamma-ray response. In fields with a large neutron contribution to the total response, this procedure may result in large uncertainties. 1.3 More precise experimental techniques may be applied if the uncertainty derived from this practice is larger than the user can accept. These techniques are not discussed here. The references in Section 8 describe some of these techniques. 1.4...

  16. Instrumental neutron activation analysis and inductively coupled plasma mass spectrometry on atmospheric biomonitors

    International Nuclear Information System (INIS)

    In a biomonitoring study aiming to find alternatives to lower epiphytes as air-quality monitors, lichens and tree bark were exposed at different sites for discontinuous periods of 2 months and continuously. Native lichens were collected as well. The contents for 22 elements were obtained by both instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Quality control as asserted by analyzing ISE-921, NIST-1547 and TL-1 was good. Losses of As and Se by volatilization during sample digestion and neutron irradiation were evident; Ca contents by ICP-MS appeared underestimated probably due to the formation of the insoluble fluoride. ICP-MS featured a better precision than INAA. Nonparametric statistics were applied to the ICP-MS replicates, to those determined by INAA, and to compare the results of both techniques. High or even excellent correlations were found between replicates in INAA, whereas, in ICP-MS, Cr and Ta were just fairly or not correlated. As an overall comparison of the techniques, biased results were found for As, Ba, Ce, Cr, Cs, Hf, La, Sc, Se, Ta, and Zn; unbiased results could be found for Ca, Co, Fe, K, Na, Rb, Sb, Sm, Tb, Th, and U. (author)

  17. Linked Environments for Atmospheric Discovery (LEAD): A Cyberinfrastructure for Mesoscale Meteorology Research and Education

    Science.gov (United States)

    Droegemeier, K.

    2004-12-01

    A new National Science Foundation Large Information Technology Research (ITR) grant - known as Linked Environments for Atmospheric Discovery (LEAD) - has been funded to facilitate the identification, access, preparation, assimilation, prediction, management, analysis, mining, and visualization of a broad array of meteorological data and model output, independent of format and physical location. A transforming element of LEAD is dynamic workflow orchestration and data management, which will allow use of analysis tools, forecast models, and data repositories as dynamically adaptive, on-demand systems that can a) change configuration rapidly and automatically in response to weather; b) continually be steered by new data; c) respond to decision-driven inputs from users; d) initiate other processes automatically; and e) steer remote observing technologies to optimize data collection for the problem at hand. Having been in operation for slightly more than a year, LEAD has created a technology roadmap and architecture for developing its capabilities and placing them within the academic and research environment. Further, much of the LEAD infrastructure being developed for the WRF model, particularly workflow orchestration, will play a significant role in the nascent WRF Developmental Test Bed Center located at NCAR. This paper updates the status of LEAD (e.g., the topics noted above), its ties with other community activities (e.g., CONDUIT, THREDDS, MADIS, NOMADS), and the manner in which LEAD technologies will be made available for general use. Each component LEAD application is being created as a standards-based Web service that can be run in stand-alone configuration or chained together to build an end-to-end environment for on-demand, real time NWP. We describe in this paper the concepts, implementation plans, and expected impacts of LEAD, the underpinning of which will be a series of interconnected, heterogeneous virtual IT "Grid environments" designed to provide a

  18. Monitoring the heavy metal atmospheric deposition in Romania using the neutron activation analysis of bio-indicators

    International Nuclear Information System (INIS)

    This research is the direct result of a protocol between NIPNE-HH Bucharest, Romania and JINR-Dubna, Russia on one side, and NIPNE-HH Bucharest, Romania and the University of Trondheim, Norway on the other side. Since the summer of 1995, a systematic sampling of bio-indicators has been carried out. The bio-indicators are represented by three species of bryophytes with an endemic development in the Romanian area: Hylocomium splendens, Hypnum cupresiforme and Pleurozium schreberi. A large area of 45,000 km2, including the Carpathian Arch between the Olt River Gorge (Southern Carpathian Mountains) and the northern Romanian border (Eastern Carpathian Mountains) was covered. Some of the samples were prepared in the laboratory and analyzed by nuclear analysis methods of a high sensitivity and accuracy i.e., neutron activation analysis and atomic absorption spectrometry. Other samples are to be prepared and analyzed. The results will be shown as distribution maps for heavy metal concentrations in the studied area. The analysis were carried out at NIPNE-HH-Bucharest, JINR-Dubna and Trondheim University. Part of the results have already been included in the European Atlas of the Heavy Metal Atmospheric Depositions, published by the Northern Countries Council. The distribution maps of atmospheric depositions in Romania will also be included in the above mentioned Atlas. (author)

  19. Neutron activation analysis on sediments from Victoria Land, Antarctica. Multi-elemental characterization of potential atmospheric dust sources

    International Nuclear Information System (INIS)

    The elemental composition of 40 samples of mineral sediments collected in Victoria Land, Antarctica, in correspondence of ice-free sites, is presented. Concentration of 36 elements was determined by instrumental neutron activation analysis, INAA. The selection of 6 standard reference materials and the development of a specific analytical procedure allowed to reduce measurements uncertainties and to verify the reproducibility of the results. The decision to analyze sediment samples from Victoria Land ice-free areas is related to recent investigations regarding mineral dust content in the TALos Dome ICE core (159deg11'E; 72deg49'S, East Antarctica, Victoria Land), in which a coarse local fraction of dust was recognized. The characterization of Antarctic potential source areas of atmospheric mineral dust is the first step to identify the active sources of dust for the Talos Dome area and to reconstruct the atmospheric pathways followed by air masses in this region during different climatic periods. Principal components analysis was used to identify elements and samples correlations; attention was paid specially to rare earth elements (REE) and incompatible/compatible elements (ICE) in respect to iron, which proved to be the most discriminating elemental groups. The analysis of REE and ICE concentration profiles supported evidences of chemical weathering in ice-free areas of Victoria Land, whereas cold and dry climate conditions of the Talos Dome area and in general of East Antarctica. (author)

  20. Study of the long-range transport of atmospheric pollutants by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Aerosol samples were collected to study the characteristics of marine aerosols in the different western Pacific ocean areas. During the first cruise from 15 October to 25 November 1989, aerosol samples were collected with a kA-200 Andersen cascade impactor and a kB-120 sampler. Instrumental neutron activation analysis was used to determine the elemental composition of the aerosols. The concentrations of crustal and pollution elements in aerosols were higher over the ocean area close to the China coast and decreased very rapidly with increasing distance from land. The morphology and elemental composition of aerosol particles showed that the seasalt particles may conglomerate with small crustal and pollution particles from land to form large particles. (author). 4 refs, 1 fig., 1 tab

  1. Long-Term Atmospheric Corrosion of Aluminum Alloy 2024-T4 in a Coastal Environment

    Science.gov (United States)

    Zhang, Teng; He, Yuting; Cui, Ronghong; An, Tao

    2015-07-01

    Aluminum alloy 2024-T4 specimens were exposed to atmosphere for 7, 12, and 20 years, respectively, to study long-term corrosion in a coastal environment. One-directional corrosion region and cross-directional corrosion region were defined according to corrosion characters. The statistical regularities, surface appearance, corrosion products, and cross-sectional morphology of both regions were investigated. It was found that the minimum remaining thicknesses of each region can be described by a normal distribution and linearly decrease as the exposure time is increased from 7 to 20 years. The corrosion pits, chlorine ions, and interlinked inner pits are promoting exfoliation, and the alloy's corrosion susceptibility along the long transverse direction is strongly location dependent due to the restrictions imposed by the side material.

  2. Land-Atmosphere Interactions in Cold Environments (LATICE): The role of Atmosphere - Biosphere - Cryosphere - Hydrosphere interactions in a changing climate

    Science.gov (United States)

    Burkhart, J. F.; Tallaksen, L. M.; Stordal, F.; Berntsen, T.; Westermann, S.; Kristjansson, J. E.; Etzelmuller, B.; Hagen, J. O.; Schuler, T.; Hamran, S. E.; Lande, T. S.; Bryn, A.

    2015-12-01

    Climate change is impacting the high latitudes more rapidly and significantly than any other region of the Earth because of feedback processes between the atmosphere and the underlying surface. A warmer climate has already led to thawing of permafrost, reducing snow cover and a longer growing season; changes, which in turn influence the atmospheric circulation and the hydrological cycle. Still, many studies rely on one-way coupling between the atmosphere and the land surface, thereby neglecting important interactions and feedbacks. The observation, understanding and prediction of such processes from local to regional and global scales, represent a major scientific challenge that requires multidisciplinary scientific effort. The successful integration of earth observations (remote and in-situ data) and model development requires a harmonized research effort between earth system scientists, modelers and the developers of technologies and sensors. LATICE, which is recognized as a priority research area by the Faculty of Mathematics and Natural Sciences at the University of Oslo, aims to advance the knowledge base concerning land atmosphere interactions and their role in controlling climate variability and climate change at high northern latitudes. The consortium consists of an interdisciplinary team of experts from the atmospheric and terrestrial (hydrosphere, cryosphere and biosphere) research groups, together with key expertise on earth observations and novel sensor technologies. LATICE addresses critical knowledge gaps in the current climate assessment capacity through: Improving parameterizations of processes in earth system models controlling the interactions and feedbacks between the land (snow, ice, permafrost, soil and vegetation) and the atmosphere at high latitudes, including the boreal, alpine and artic zone. Assessing the influence of climate and land cover changes on water and energy fluxes. Integrating remote earth observations with in-situ data and

  3. Atmospheric Dispersal of Bioactive Streptomyces albidoflavus Strains Among Terrestrial and Marine Environments.

    Science.gov (United States)

    Sarmiento-Vizcaíno, Aida; Braña, Alfredo F; González, Verónica; Nava, Herminio; Molina, Axayacatl; Llera, Eva; Fiedler, Hans-Peter; Rico, José M; García-Flórez, Lucía; Acuña, José L; García, Luis A; Blanco, Gloria

    2016-02-01

    Members of the Streptomyces albidoflavus clade, identified by 16S rRNA sequencing and phylogenetic analyses, are widespread among predominant terrestrial lichens (Flavoparmelia caperata and Xanthoria parietina) and diverse intertidal and subtidal marine macroalgae, brown red and green (Phylum Heterokontophyta, Rhodophyta, and Chlorophyta) from the Cantabrian Cornice. In addition to these terrestrial and coastal temperate habitats, similar strains were also found to colonize deep-sea ecosystems and were isolated mainly from gorgonian and solitary corals and other invertebrates (Phylum Cnidaria, Annelida, Echinodermata, Arthropoda, and Porifera) living up to 4700-m depth and at a temperature of 2-4 °C in the submarine Avilés Canyon. Similar strains have been also repeatedly isolated from atmospheric precipitations (rain drops, snow, and hailstone) collected in the same area throughout a year observation time. These ubiquitous strains were found to be halotolerant, psychrotolerant, and barotolerant. Bioactive compounds with diverse antibiotic and cytotoxic activities produced by these strains were identified by high-performance liquid chromatography (HPLC) and database comparison. These include antibacterials (paulomycins A and B), antifungals (maltophilins), antifungals displaying also cytotoxic activities (antimycins and 6-epialteramides), and the antitumor compound fredericamycin. A hypothetical dispersion model is here proposed to explain the biogeographical distribution of S. albidoflavus strains in terrestrial, marine, and atmospheric environments. PMID:26224165

  4. Atmospheric electric field measurements in urban environment and the pollutant aerosol weekly dependence

    International Nuclear Information System (INIS)

    The weekly dependence of pollutant aerosols in the urban environment of Lisbon (Portugal) is inferred from the records of atmospheric electric field at Portela meteorological station (38°47′N, 9°08′W). Measurements were made with a Bendorf electrograph. The data set exists from 1955 to 1990, but due to the contaminating effect of the radioactive fallout during 1960 and 1970s, only the period between 1980 and 1990 is considered here. Using a relative difference method a weekly dependence of the atmospheric electric field is found in these records, which shows an increasing trend between 1980 and 1990. This is consistent with a growth of population in the Lisbon metropolitan area and consequently urban activity, mainly traffic. Complementarily, using a Lomb–Scargle periodogram technique the presence of a daily and weekly cycle is also found. Moreover, to follow the evolution of theses cycles, in the period considered, a simple representation in a colour surface plot representation of the annual periodograms is presented. Further, a noise analysis of the periodograms is made, which validates the results found. Two datasets were considered: all days in the period, and fair-weather days only. (letter)

  5. Functionalization of graphene by atmospheric pressure plasma jet in air or H2O2 environments

    Science.gov (United States)

    Huang, Weixin; Ptasinska, Sylwia

    2016-03-01

    The functionalization of graphene, which deforms its band structure, can result in a metal-semiconductor transition. In this work, we report a facile strategy to oxidize single-layer graphene using an atmospheric pressure plasma jet (APPJ) that generates a variety of reactive plasma species at close to ambient temperature. We systematically characterized the oxygen content and chemical structure of the graphene films after plasma treatment under different oxidative conditions (ambient air atmosphere or hydrogen peroxide solution) by X-ray Photoelectron Spectroscopy (XPS). Plasma-treated graphene films containing more than 40% oxygen were obtained in both oxidative environments. Interestingly, prolonged irradiation led to the reduction of graphene oxides. N-doping of graphene also occurred during the APPJ treatment in H2O2 solution; the nitrogen content of the doped graphene was dependent on the duration of irradiation and reached up to 8.1% within 40 min. Moreover, the H2O2 solution served as a buffer layer that prevented damage to the graphene during plasma irradiation. Four-point probe measurement revealed an increase in sheet resistance of the plasma-treated graphene, indicating the transition of the material property from semi-metallic to semiconducting.

  6. Initial corrosion behavior of a copper-clad plate in typical outdoor atmospheric environments

    Science.gov (United States)

    Yi, Pan; Xiao, Kui; Ding, Kangkang; Yan, Lidan; Dong, Chaofang; Li, Xiaogang

    2016-01-01

    A copper-clad printed circuit board (PCB-Cu) was subjected to long-term exposure test under typical Chinese atmospheric environments to study corrosion failure mechanisms. The corrosion behavior was investigated by analyzing electrochemical impedance, scanning Kelvin probes, stereo and scanning electron microscopes, and energy-dispersive spectra. Results showed that the initial surface potential was unevenly distributed. The outdoor PCB-Cu samples suffered severe corrosion caused by dust particles, contaminated media, and microorganisms after long-term atmospheric exposure. The initial localized corrosion was exacerbated and progressed to general corrosion for samples in Turpan, Beijing, and Wuhan under prolonged exposure, whereas PCB-Cu in Xishuangbanna was only slightly corroded. The tendency for electrochemical migration (ECM) of PCB-Cu was relatively low when applied with a bias voltage of 12 V. ECM was only observed in the PCB-Cu samples in Beijing. Contaminated medium and high humidity synergistically affected ECM corrosion in PCB-Cu materials. [Figure not available: see fulltext.

  7. Neutron Reference Benchmark Field Specification: ACRR Free-Field Environment (ACRR-FF-CC-32-CL).

    Energy Technology Data Exchange (ETDEWEB)

    Vega, Richard Manuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Griffin, Patrick J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vehar, David W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-07-01

    This report was put together to support the International Atomic Energy Agency (IAEA) REAL- 2016 activity to validate the dosimetry community’s ability to use a consistent set of activation data and to derive consistent spectral characterizations. The report captures details of integral measurements taken in the Annular Core Research Reactor (ACRR) central cavity free-field reference neutron benchmark field. The field is described and an “a priori” calculated neutron spectrum is reported, based on MCNP6 calculations, and a subject matter expert (SME) based covariance matrix is given for this “a priori” spectrum. The results of 31 integral dosimetry measurements in the neutron field are reported.

  8. Common inorganic ions are efficient catalysts for organic reactions in atmospheric aerosols and other natural environments

    Science.gov (United States)

    Nozière, B.; Dziedzic, P.; Córdova, A.

    2009-01-01

    In this work, inorganic ammonium ions, NH4+, and carbonate ions, CO32-, are reported for the first time as catalysts for organic reactions in atmospheric aerosols and other natural environments at the Earth's surface. These reactions include the formation of C-C and C-O bonds by aldol condensation and acetal formation, and reveal a new aspect of the interactions between organic and inorganic materials in natural environments. The catalytic properties of inorganic ammonium ions, in particular, were not previously known in chemistry. The reactions were found to be as fast in tropospheric ammonium sulfate composition as in concentrated sulfuric acid. The ubiquitous presence and large concentrations of ammonium ions in tropospheric aerosols would make of ammonium catalysis a main consumption pathway for organic compounds in these aerosols, while acid catalysis would have a minor contribution. In particular, ammonium catalysis would account quantitatively for the aging of carbonyl compounds into secondary ''fulvic'' compounds in tropospheric aerosols, a transformation affecting the optical properties of these aerosols. In general, ammonium catalysis is likely to be responsible for many observations previously attributed to acid catalysis in the troposphere.

  9. Common inorganic ions are efficient catalysts for organic reactions in atmospheric aerosols and other natural environments

    Directory of Open Access Journals (Sweden)

    B. Nozière

    2009-01-01

    Full Text Available In this work, inorganic ammonium ions, NH4+, and carbonate ions, CO32−, are reported for the first time as catalysts for organic reactions in atmospheric aerosols and other natural environments at the Earth's surface. These reactions include the formation of C–C and C–O bonds by aldol condensation and acetal formation, and reveal a new aspect of the interactions between organic and inorganic materials in natural environments. The catalytic properties of inorganic ammonium ions, in particular, were not previously known in chemistry. The reactions were found to be as fast in tropospheric ammonium sulfate composition as in concentrated sulfuric acid. The ubiquitous presence and large concentrations of ammonium ions in tropospheric aerosols would make of ammonium catalysis a main consumption pathway for organic compounds in these aerosols, while acid catalysis would have a minor contribution. In particular, ammonium catalysis would account quantitatively for the aging of carbonyl compounds into secondary ''fulvic'' compounds in tropospheric aerosols, a transformation affecting the optical properties of these aerosols. In general, ammonium catalysis is likely to be responsible for many observations previously attributed to acid catalysis in the troposphere.

  10. Neutron activation analysis of lichens for atmospheric pollution study in Sao Paulo city

    International Nuclear Information System (INIS)

    In the present study instrumental neutron activation analysis has been applied to determine the elements accumulated in samples of Canoparmelia texana, a specie of lichen, collected in regions with different levels of pollution: Intervales State Park, an area considered non polluted that belongs to Atlantic Forest ecosystem and distinct sites in the metropolitan region of Sao Paulo city. The results obtained in the analysis showed that samples collected in the clean area indicated lower concentrations of elements than those obtained for samples from metropolitan region. The concentrations of the elements Ba, Ca, Cl, Fe, K, Mn, Na, Rb and Zn were obtained at μg g-1 levels and the elements As, Br, Co, Cr, Cs, La, Sb, Sc, Se and U at ng g-1 levels. Cluster analysis was applied to classify into distinct groups the sites using the element concentrations in these samples. The accuracy and precision of the results were evaluated by IAEA 336 Lichen reference material analysis and the data given for this material were in agreement with certified values with relative standard deviations lower than 11,4%. (author)

  11. The ward atmosphere important for the psychosocial work environment of nursing staff in psychiatric in-patient care

    Directory of Open Access Journals (Sweden)

    Wann-Hansson Christine

    2011-06-01

    Full Text Available Abstract Background The nursing staff working in psychiatric care have a demanding work situation, which may be reflected in how they view their psychosocial work environment and the ward atmosphere. The aims of the present study were to investigate in what way different aspects of the ward atmosphere were related to the psychosocial work environment, as perceived by nursing staff working in psychiatric in-patient care, and possible differences between nurses and nurse assistants. Methods 93 nursing staff working at 12 general psychiatric in-patient wards in Sweden completed two questionnaires, the Ward Atmosphere Scale and the QPSNordic 34+. Data analyses included descriptive statistics, the Mann-Whitney U-test, Spearman rank correlations and forward stepwise conditional logistic regression analyses. Results The data revealed that there were no differences between nurses and nurse assistants concerning perceptions of the psychosocial work environment and the ward atmosphere. The ward atmosphere subscales Personal Problem Orientation and Program Clarity were associated with a psychosocial work environment characterized by Empowering Leadership. Program Clarity was related to the staff's perceived Role Clarity, and Practical Orientation and Order and Organization were positively related to staff perceptions of the Organizational Climate. Conclusions The results from the present study indicate that several ward atmosphere subscales were related to the nursing staff's perceptions of the psychosocial work environment in terms of Empowering Leadership, Role Clarity and Organizational Climate. Improvements in the ward atmosphere could be another way to accomplish improvements in the working conditions of the staff, and such improvements would affect nurses and nurse assistants in similar ways.

  12. Tritium distribution in the environment in the vicinity of a chronic atmospheric source-assessment of the steady state hypothesis

    International Nuclear Information System (INIS)

    The Savannah River Site (SRS) is a major radionuclide production center. Tritium has been released to the atmosphere over the 36 year period of operation. The tritiated water concentration of the atmosphere, rain, vegetation and food have been routinely monitored during this period. Special studies have been made of tritium in soils and in the organic fractions of these same materials. The available data suggest that the average tritium concentration in the components of the terrestrial environment have approached a steady state with the two main sources of tritium, rainfall and atmospheric water vapor

  13. Organic Aerosols in Rural and Remote Atmospheric Environments: Insights from Aerosol Mass Spectrometry

    Science.gov (United States)

    Zhang, Q.; Jimenez, J.; Ulbrich, I.; Dunlea, E.; Decarlo, P.; Huffman, A.; Allan, J.; Coe, H.; Alfarra, R.; Canagaratna, M.; Onasch, T.; Jayne, J.; Worsnop, D.; Takami, A.; Miyoshi, T.; Shimono, A.; Hatakeyama, S.; Weimer, S.; Demerjian, K.; Drewnick, F.; Schneider, J.; Middlebrook, A.; Bahreini, R.; Cotrell, L.; Griffin, R.; Leaitch, R.; Li, S.; Hayden, K.; Rautiainen, J.

    2006-12-01

    Organic matter usually accounts for a large fraction of the fine particle mass in rural and remote atmospheres. However, little is known about the sources and properties of this material. Here we report findings on the characteristics and the major types of organic aerosols (OA) in urban downwind, high elevation, forested, and marine atmospheres based on analyses of more than 20 highly time resolved AMS datasets sampled from various locations in the mid-latitude Northern Hemisphere. Organic aerosol components are extracted from these datasets using a custom multiple component mass spectral analysis technique and the Positive Matrix Factorization (PMF) method. These components are evaluated according to their extracted mass spectra and correlations to aerosol species, such as sulfate, nitrate, and elemental carbon, and gas-phase tracer compounds, such as CO and NOx. We have identified a hydrocarbon-like organic aerosol (HOA) component similar in mass spectra to the hydrocarbon substances observed at urban locations. We have also identified several oxygenated OA (OOA) components that show different fragmentation patterns and oxygen to carbon ratios in their mass spectra. Two OOA components a highly oxygenated that has mass spectrum resembling that of fulvic acid (a model compound representative for highly processed/oxidized organics in the environment) and a less oxygenated OOA component, whose spectrum is dominated with ions that are mainly associated with carbonyls and alcohols, are very frequently observed at various rural/remote sites. The oxygenated OOA component is more prevalent at downwind sites influenced by urban transport and the less oxygenated shows correlation to biogenic chamber OA at some locations. Compared to the total OOA concentration, HOA is generally very small and accounts for high elevation site (the Whistler Mountain Summit, Canada) of North America. Finally, an attempt will be made to address the relative importance of secondary vs. primary

  14. Activation consideration for a test cell side watt design in an intense neutron environment

    International Nuclear Information System (INIS)

    In the fusion material irradiation test facility (FMIT), an intense neutron radiation is generated by bombarding a liquid lithium target with 35 MeV deuterons. The configuration of the FMIT test cell is a 5 ft x 6 ft x 8 ft cube. The side wall which accomodates the experiment/test assembly is currently specified as 54 inches of steel with the first twelve inches being used as part of the test cell cooling panel. The steel wall is augmented by a 4 ft high density concrete shielding door to provide the necessary biological shield. Stainless steel, carbon steel, and lead were investigated as candidate materials for the side wall. The ANISN-W code was utilized to evaluate the shielding effectiveness as well as production of activation products in the shield. The activation cross section data weighted by the unperturbed neutron flux was compared with the cross section data weighted by the neutron flux in the shield to get the spectrum effect on the cross sections. Impacts of carbon, boron, as well as trace elements of steel impurities on the neutron distribution in the shield as well as on neutron activation were assessed

  15. Modeling the Impacts of the Large-Scale Atmospheric Environment on Inland Flooding during the Landfall of Hurricane Floyd (1999)

    OpenAIRE

    Qianhong Tang; Lian Xie; Gary M. Lackmann; Bin Liu

    2013-01-01

    The contribution of the large-scale atmospheric environment to precipitation and flooding during Hurricane Floyd was investigated in this study. Through the vortex removal technique in the Weather Research and Forecasting (WRF) model, the vortex associated with Hurricane Floyd (1999) was mostly removed in the model initial conditions and subsequent integration. Results show that the environment-induced precipitation can account for as much as 22% of total precipitation in the innermost model ...

  16. Spatial-Spectral Studies of Cometary Volatiles and the Physical Environment of Inner Cometary Atmospheres

    Science.gov (United States)

    Bonev, Boncho P.; Fougere, Nicolas; Villanueva, Geronimo L.; Mumma, Michael J.; Combi, Michael R.; DiSanti, Michael A.; Paganini, Lucas; Cordiner, Martin; Gibb, Erika L.; Milam, Stefanie N.

    2015-11-01

    How is water released in comets - directly from the nucleus versus sublimation from icy grains in the coma? How common and how prevalent are icy grains as a source of gas-phase water (and other volatiles) among the active comet population? These questions are being addressed through synergy between spatial-spectral studies of native volatiles in comets and the physical models tested against them. This synergy is extending the state-of-the-art in both domains. Ground-based near-IR spectroscopy (Keck, NASA IRTF, and ESO VLT) allowed measurements of spatially resolved inner coma temperatures and column densities for H2O - the most abundant volatile in the coma. These measurements motivated the inclusion of new physics in the models. The evolved models now open new questions and trigger improvement in the accuracy of measured temperature profiles, most recently extended to other molecules (HCN in the near-IR) and to other wavelength domains (CH3OH, through ALMA; S. Milam et al., this meeting). The net result is deeper quantitative insight into the competition among processes that cause heating and cooling of the coma and into the prevalent mechanism(s) for release of native volatiles in the gas phase.The same inner-coma modeling formalisms are used to interpret both the environment of Rosetta's mission target (67P/Churyumov-Gerasimenko) and those from the ground-based observations reported here (Combi et al. 2015, LPSC, #1714; Fougere et al., this meeting). While ground-based spectroscopy offers less detail than in-situ missions, it can probe the comae of many comets that may differ greatly from one another and from Rosetta's target, thereby assessing the extent to which the inner-coma environment of 67P is unique, and how it relates to other comets.We gratefully acknowledge support from NASA Planetary Atmospheres, Solar System Workings, Planetary Astronomy, and Astrobiology programs, and from NSF Astronomy and Astrophysics Research Grants program.

  17. Applied research and development of neutron activation analysis - The study on human health and environment by neutron activation analysis of biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seung Yeon; Yoo, Jong Ik; Lee, Jae Kwang; Lee, Sung Jun; Lee, Sang Sun; Jeon, Ki Hong; Na, Kyung Won; Kang, Sang Hun [Yonsei University, Seoul (Korea)

    2000-04-01

    With the development of the precise quantitative analytical method for the analysis of trace elements in the various biological samples such as hair and food, evaluation in view of health and environment to the trace elements in various sources which can be introduced inside human body was done. The trace elemental distribution in Korean total diet and representative food stuff was identified first. With the project the elemental distributions in supplemental healthy food and Korean and Chinese origin oriental medicine were identified. The amount of trace elements ingested with the hair analysis of oriental medicine takers were also estimated. The amounts of trace elements inhaled with the analysis of foundry air, blood and hair of foundry workers were also estimated. The basic estimation method in view of health and environment with the neutron activation analysis of biological samples such as foods and hair was established with the result. Nationwide usage system of the NAA facility in Hanaro in many different and important areas of biological area can be initiated with the results. The output of the project can support public heath, environment, and medical research area. The results can be applied for the process of micronutrients enhanced health food production and for the health safety and health status enhancement with the additional necessary data expansion and the development of various evaluation technique. 19 refs., 7 figs., 23 tabs. (Author)

  18. Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

    Energy Technology Data Exchange (ETDEWEB)

    Poellaenen, R

    2002-05-01

    In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has

  19. Nuclear fuel particles in the environment - characteristics, atmospheric transport and skin doses

    International Nuclear Information System (INIS)

    In the present thesis, nuclear fuel particles are studied from the perspective of their characteristics, atmospheric transport and possible skin doses. These particles, often referred to as 'hot' particles, can be released into the environment, as has happened in past years, through human activities, incidents and accidents, such as the Chernobyl nuclear power plant accident in 1986. Nuclear fuel particles with a diameter of tens of micrometers, referred to here as large particles, may be hundreds of kilobecquerels in activity and even an individual particle may present a quantifiable health hazard. The detection of individual nuclear fuel particles in the environment, their isolation for subsequent analysis and their characterisation are complicated and require well-designed sampling and tailored analytical methods. In the present study, the need to develop particle analysis methods is highlighted. It is shown that complementary analytical techniques are necessary for proper characterisation of the particles. Methods routinely used for homogeneous samples may produce erroneous results if they are carelessly applied to radioactive particles. Large nuclear fuel particles are transported differently in the atmosphere compared with small particles or gaseous species. Thus, the trajectories of gaseous species are not necessarily appropriate for calculating the areas that may receive large particle fallout. A simplified model and a more advanced model based on the data on real weather conditions were applied in the case of the Chernobyl accident to calculate the transport of the particles of different sizes. The models were appropriate in characterising general transport properties but were not able to properly predict the transport of the particles with an aerodynamic diameter of tens of micrometers, detected at distances of hundreds of kilometres from the source, using only the current knowledge of the source term. Either the effective release height has been higher

  20. Testimony presented to the Committee on Science and Technology's Subcommittee on Environment and the Atmosphere

    International Nuclear Information System (INIS)

    This report contains the basis for oral testimony to the House Committee on Science and Technology's Subcommittee on Environment and the Atmosphere in November 1975. The subject of the hearings was ''Effects and Costs of Long-term Exposure to Low Levels of Manmade Pollutants'' and the purpose of the hearings was to increase the awareness of low-level pollution and its impacts on human health, agriculture and climate. This report contains information related to impacts of low-level pollutants on human health. I have attempted to point out the major adverse health effects (e.g., carcinogenic, mutagenic and teratogenic) that may result from chronic exposure to low-level pollutants. Also addressed are important questions such as what do we know about dose-response relations for chronic exposure to pollutants and how can we establish comparisons with knowledge obtained from exposure to ionizing radiations. The report also considers the wisdom of extrapolating from health effects data obtained from acute, high-level exposures to chronic, low-level exposure conditions. Lastly, a few examples of the societal costs related to low-level pollutant exposure are presented

  1. Aerothermodynamic environment and thermal protection for a Titan aerocapture vehicle. [Saturn satellite atmospheric entry

    Science.gov (United States)

    Green, M. J.; Moss, J. N.; Wilson, J. F.

    1984-01-01

    This paper presents thermal protection system (TPS) requirements for a potential Titan aerocapture vehicle. Shock-layer solutions are obtained for a nominal trajectory through the current Titan model atmosphere. Fully laminar and fully turbulent solutions are presented along the blunted fore-cone in the windward symmetry plane of a bent-biconic vehicle. Using these solutions to define the aerothermodynamic environment, transient material-response solutions are obtained for a Galileo-type TPS with a carbon-phenolic ablator heat shield. Shock-layer results indicate that turbulent flow is the more realistic flow condition. They also show that the lengthy aerocapture heating pulse is dominated by convective heating. The TPS results show that the required insulation thickness is uniformly about 4 cm along the fore-cone because of the long heat-soak period. The total heat-shield thickness is 6.4 cm at the stagnation point, and 4.7 cm near the end of the fore-cone. These TPS requirements are greater than those presented in a previous Titan aerocapture study.

  2. ENTRYSAT: A 3U Cubesat to Study the Re-Entry Atmospheric Environment

    Science.gov (United States)

    Garcia, R. F.; Chaix, J.; Mimoun, D.; EntrySat student Team

    2014-04-01

    The EntrySat is a 3U CubeSat designed to study the uncontrolled atmospheric re-entry. The project, developed by ISAE in collaboration with ONERA, is funded by CNES and is intended to be launched in January 2016, in the context of the QB50 network. The scientific goal is to relate the kinematics of the satellite with the aerothermodynamic environment during re-entry. In particular, data will be compared with the computations of MUSIC/FAST, a new 6-degree of freedom code developed by ONERA to predict the trajectory of space debris. According to these requirements, the satellite will measure the temperature, pressure, heat flux, and drag force during re-entry, as well as the trajectory and attitude of the satellite. One of the major technological challenges is the retrieval of data during the re-entry phase, which will be based on the Iridium satellite network. The system design is based on the use of commercial COTS components, and is mostly developed by students from ISAE. As such, the EntrySat has an important educational value in the formation of young engineers.

  3. Limestone surfaces in built-up environment as indicators of atmospheric pollution.

    Science.gov (United States)

    Vella, A J; Camilleri, A; Tabone Adami, J P

    1996-12-01

    The concentration of sulphate on limestone surfaces of the external walls of churches in Malta is shown to be related to their position and distance from a power station, the main local point source of sulphur dioxide pollution. Limestone powder collected from these surfaces was examined for the presence of particles which, under low-power optical microscopy, appear as shiny black amorphous bodies which were interpreted as soot particles; the abundance of these bodies was expressed as a 'black particle count' (BPC). The degree of sulphation and BPC were shown to be correlated with each other and both appeared to be strongly dependent on the prevailing wind. The BPC contour map indicated an important contribution to the parameter from vehicular traffic. It is suggested that the degree of sulphation and BPC of limestone surfaces from the built environment should function as environmental indicators of the relative air quality with respect to SO2 and soot pollution. This data is possibly more accurately representative of the relative long-term air-quality status of different areas of habitation than that deduced from single or episodic measurements of atmospheric pollutant levels. PMID:24194411

  4. Observations on the use of membrane filtration and liquid impingement to collect airborne microorganisms in various atmospheric environments

    Science.gov (United States)

    Griffin, Dale W.; Gonzalez, C.; Teigell, N.; Petrosky, T.; Northup, D.E.; Lyles, M.

    2011-01-01

    The influence of sample-collection-time on the recovery of culturable airborne microorganisms using a low-flow-rate membrane-filtration unit and a high-flow-rate liquid impinger were investigated. Differences in recoveries were investigated in four different atmospheric environments, one mid-oceanic at an altitude of ~10.0 m, one on a mountain top at an altitude of ~3,000.0 m, one at ~1.0 m altitude in Tallahassee, Florida, and one at ~1.0 m above ground in a subterranean-cave. Regarding use of membrane filtration, a common trend was observed: the shorter the collection period, the higher the recovery of culturable bacteria and fungi. These data also demonstrated that lower culturable counts were common in the more remote mid-oceanic and mountain-top atmospheric environments with bacteria, fungi, and total numbers averaging (by sample time or method categories) microorganisms is limited in 'extreme' atmospheric environments and thus the use of a 'limited' methodology in these environments must be taken into account; and (4) the atmosphere culls, i.e., everything is not everywhere. ?? 2010 US Government.

  5. Managing NIF safety equipment in a high neutron and gamma radiation environment.

    Science.gov (United States)

    Datte, Philip; Eckart, Mark; Jackson, Mark; Khater, Hesham; Manuel, Stacie; Newton, Mark

    2013-06-01

    The National Ignition Facility (NIF) is a 192 laser beam facility that supports the Inertial Confinement Fusion program. During the ignition experimental campaign, the NIF is expected to perform shots with varying fusion yield producing 14 MeV neutrons up to 20 MJ or 7.1 × 10(18) neutrons per shot and a maximum annual yield of 1,200 MJ. Several infrastructure support systems will be exposed to varying high yield shots over the facility's 30-y life span. In response to this potential exposure, analysis and testing of several facility safety systems have been conducted. A detailed MCNP (Monte Carlo N-Particle Transport Code) model has been developed for the NIF facility, and it includes most of the major structures inside the Target Bay. The model has been used in the simulation of expected neutron and gamma fluences throughout the Target Bay. Radiation susceptible components were identified and tested to fluences greater than 10(13) (n cm(-2)) for 14 MeV neutrons and γ-ray equivalent. The testing includes component irradiation using a 60Co gamma source and accelerator-based irradiation using 4- and 14- MeV neutron sources. The subsystem implementation in the facility is based on the fluence estimates after shielding and survivability guidelines derived from the dose maps and component tests results. This paper reports on the evaluation and implementation of mitigations for several infrastructure safety support systems, including video, oxygen monitoring, pressure monitors, water sensing systems, and access control interfaces found at the NIF. PMID:23629064

  6. Modelling strategies of the soil plant atmosphere continuum in water limited environments and elevated atmospheric carbon dioxide

    International Nuclear Information System (INIS)

    Higher temperatures and changes in rainfall patterns have been forecasted for the future because of higher levels of carbon dioxide in the atmosphere. Warmer temperatures may cause an increase in evapotranspiration (ET) demand. A reduction in rainfall could heighten the severity and duration of drought in arid and semi-arid regions. This paper presented the water transfer scheme which includes water uptake by roots. It also described the interaction between ET and carbon dioxide enrichment. The predicted response of a plant canopy in relation to energy exchange processes was also tested for elevated atmospheric carbon dioxide level. Simulated and measured canopy conductances were reduced by about 30 per cent under elevated carbon dioxide under ideal water supply conditions. A 6 per cent reduction in both simulated and measured seasonal water use was observed under ideal conditions, while a 2 per cent reduction was observed under suboptimum irrigation. The modelling framework also included adaptation and functioning of root system of woody plant canopies. The hypothesis that water that has been relocated via hydraulic lift prevents the upper soil layers from becoming extremely dry was confirmed. Soil layers close to the surface were found to maintain soil water potential between -1.0 and -1.3 MPs during the drought period as well as under 2 different rainfall regimes. In contrast, the absence of hydraulic lift caused the soil layer close to the surface to drop to -20 MPa and -28 MPa. An additional amount of water for plant transpiration was not provided in any large amounts when water was relocated via hydraulic lift. It was concluded that carbon dioxide modelling and transpiration interactions may produce accurate estimates of canopy water use under the predicted climate change. Hydraulic lift was found to be more important for redistribution of soil moisture than for canopy transpiration

  7. Atmosphere

    Science.gov (United States)

    Ghosh, D.; Mitra, S. K.

    2014-05-01

    This paper investigates the high-temperature corrosion behavior of microstructurally different regions of the weldment of 9 Cr-1 Mo steel used in thermal power plant boiler in SO2 + O2 environment. The weldment is produced by tungsten inert gas welding method, and the different regions of the weldment (weld metal, heat-affected zone, and base metal) are exposed in SO2 + O2 (ratio 2:1) environment at 973 K for 120 h. The reaction kinetics and corrosion growth rate of different regions of weldment in isothermal condition are evaluated. The post corroded scales of the different specimens are studied in SEM, EDS, and XRD. The results indicate that the weld metal shows higher corrosion rate followed by HAZ and base metal. The higher rate of corrosion of weldmetal is mainly attributed to the least protective inner scale of Cr2O3 with minimum Cr Content. This is due to the formation of delta ferrite, which leads to the precipitation of the Cr-based secondary phases and depletes the free Cr from the matrix. The thermal cycles during welding at high temperature are favorable for the formation of delta ferrite. On the other hand, in absence of delta ferrite, the base metal and HAZ regions of the weldment show lower corrosion rate than weld metal. The difference in corrosion rate in the three regions of the weldment is supplemented by post-corroded scale characterizations.

  8. A Dropsonde UAV for Atmospheric Sensing in a Turbulent Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Dropsondes are one of the primary atmospheric measurement tools available to researchers. Current dropsondes are deployed with a free fall parachute trajectory,...

  9. Fixing atmospheric CO2 by environment adaptive sorbent and renewable energy

    Science.gov (United States)

    Wang, T.; Liu, J.; Ge, K.; Fang, M.

    2014-12-01

    Fixing atmospheric CO2, followed by geologic storage in remote areas is considered an environmentally secure approach to climate mitigation. A moisture swing sorbent was investigated in the laboratory for CO2 capture at a remote area with humid and windy conditions. The energy requirement of moisture swing absorption could be greatly reduced compared to that of traditional high-temperature thermal swing, by assuming that the sorbent can be naturally dried and regenerated at ambient conditions. However, for currently developed moisture swing materials, the CO2 capacity would drop significantly at high relative humidity. The CO2 capture amount can be reduced by the poor thermodynamics and kinetics at high relative humidity or low temperature. Similar challenges also exist for thermal or vacuum swing sorbents. Developing sorbent materials which adapt to specific environments, such as high humidity or low temperature, can ensure sufficient capture capacity on the one hand, and realize better economics on the other hand (Figure 1) .An environment adaptive sorbent should have the abilities of tunable capacity and fast kinetics at extreme conditions, such as high humidity or low temperature. In this presentation, the possibility of tuning CO2 absorption capacity of a polymerized ionic liquid material is discussed. The energy requirement evaluation shows that tuning the CO2 binding energy of sorbent, rather than increasing the temperature or reducing the humidity of air, could be much more economic. By determining whether the absorption process is controlled by physical diffusion controlled or chemical reaction, an effective approach to fast kinetics at extreme conditions is proposed. A shrinking core model for mass transfer kinetics is modified to cope with the relatively poor kinetics of air capture. For the studied sample which has a heterogeneous structure, the kinetic analysis indicates a preference of sorbent particle size optimization, rather than support layer

  10. Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology.

    Science.gov (United States)

    Allajbeu, Sh; Yushin, N S; Qarri, F; Duliu, O G; Lazo, P; Frontasyeva, M V

    2016-07-01

    Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc-La-Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation. PMID:27044293

  11. An improved criterion for new particle formation in diverse atmospheric environments

    Directory of Open Access Journals (Sweden)

    C. Kuang

    2010-09-01

    Full Text Available A dimensionless theory for new particle formation (NPF was developed, using an aerosol population balance model incorporating recent developments in nucleation rates and measured particle growth rates. Based on this theoretical analysis, it was shown that a dimensionless parameter LΓ, characterizing the ratio of the particle scavenging loss rate to the particle growth rate, exclusively determined whether or not NPF would occur on a particular day. This parameter determines the probability that a nucleated particle will grow to a detectable size before being lost by coagulation with the pre-existing aerosol. Cluster-cluster coagulation was shown to contribute negligibly to this survival probability under conditions pertinent to the atmosphere. Data acquired during intensive measurement campaigns in Tecamac (MILAGRO, Atlanta (ANARChE, Boulder, and Hyytiälä (QUEST II, QUEST IV, and EUCAARI were used to test the validity of LΓ as an NPF criterion. Measurements included aerosol size distributions down to 3 nm and gas-phase sulfuric acid concentrations. The model was applied to seventy-seven NPF events and nineteen non-events (characterized by growth of pre-existing aerosol without NPF measured in diverse environments with broad ranges in sulfuric acid concentrations, ultrafine number concentrations, aerosol surface areas, and particle growth rates (nearly two orders of magnitude. Across this diverse data set, a nominal value of LΓ=0.7 was found to determine the boundary for the occurrence of NPF, with NPF occurring when LΓ<0.7 and being suppressed when LΓ>0.7. Moreover, nearly 45% of measured LΓ values associated with NPF fell in the relatively narrow range of 0.1<LΓ<0.3.

  12. Optimising the neutron environment of Radiation Portal Monitors: a computational optimisation study

    CERN Document Server

    Gilbert, Mark R; Packer, Lee W

    2015-01-01

    Efficient and reliable detection of radiological or nuclear threats is a crucial part of national and international efforts to prevent terrorist activities. Radiation Portal Monitors (RPMs), which are deployed worldwide, are intended to interdict smuggled fissile material by detecting emissions of neutrons and gamma rays. However, considering the range and variety of threat sources, vehicular and shielding scenarios, and that only a small signature is present, it is important that the design of the RPMs allows these signatures to be accurately differentiated from the environmental background. Using Monte-Carlo neutron-transport simulations of a model helium-3 detector system we have conducted a parameter study to identify the optimum combination of detector shielding and collimation that maximises the sensitivity of RPMs. These structures, which could be simply and cost-effectively added to existing RPMs, can improve the detector response by more than a factor of two relative to an unmodified, bare design. Fu...

  13. Why galactic gamma-ray bursts might depend on environment: Blast waves around neutron stars

    Science.gov (United States)

    Rees, Martin J.; Meszaros, Peter; Begelman, Mitchell C.

    1994-01-01

    Although galactic models for gamma-ray bursts are hard to reconcile with the isotropy data, the issue is still sufficiently open that both options should be explored. The most likely 'triggers' for bursts in our Galaxy would be violent disturbances in the magnetospheres of neutron stars. Any event of this kind is likely to expel magnetic flux and plasma at relativistic speed. Such ejecta would be braked by the interstellar medium (ISM), and a gamma-ray flash may result from this interaction. The radiative efficiency, of this mechanism would depend on the density of the circumstellar ISM. Therefore, even if neutron stars were uniformly distributed in space (at least within 1-2 kpc of the Sun), the observed locations of bursts would correlate with regions of above-average ISM density.

  14. Optimising the neutron environment of Radiation Portal Monitors: A computational study

    Science.gov (United States)

    Gilbert, Mark R.; Ghani, Zamir; McMillan, John E.; Packer, Lee W.

    2015-09-01

    Efficient and reliable detection of radiological or nuclear threats is a crucial part of national and international efforts to prevent terrorist activities. Radiation Portal Monitors (RPMs), which are deployed worldwide, are intended to interdict smuggled fissile material by detecting emissions of neutrons and gamma rays. However, considering the range and variety of threat sources, vehicular and shielding scenarios, and that only a small signature is present, it is important that the design of the RPMs allows these signatures to be accurately differentiated from the environmental background. Using Monte-Carlo neutron-transport simulations of a model 3He detector system we have conducted a parameter study to identify the optimum combination of detector shielding, moderation, and collimation that maximises the sensitivity of neutron-sensitive RPMs. These structures, which could be simply and cost-effectively added to existing RPMs, can improve the detector response by more than a factor of two relative to an unmodified, bare design. Furthermore, optimisation of the air gap surrounding the helium tubes also improves detector efficiency.

  15. Optimising the neutron environment of Radiation Portal Monitors: A computational study

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, Mark R., E-mail: mark.gilbert@ccfe.ac.uk [United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Ghani, Zamir [United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); McMillan, John E. [Department of Physics and Astronomy, University of Sheffield, Hicks building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Packer, Lee W. [United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-09-21

    Efficient and reliable detection of radiological or nuclear threats is a crucial part of national and international efforts to prevent terrorist activities. Radiation Portal Monitors (RPMs), which are deployed worldwide, are intended to interdict smuggled fissile material by detecting emissions of neutrons and gamma rays. However, considering the range and variety of threat sources, vehicular and shielding scenarios, and that only a small signature is present, it is important that the design of the RPMs allows these signatures to be accurately differentiated from the environmental background. Using Monte-Carlo neutron-transport simulations of a model {sup 3}He detector system we have conducted a parameter study to identify the optimum combination of detector shielding, moderation, and collimation that maximises the sensitivity of neutron-sensitive RPMs. These structures, which could be simply and cost-effectively added to existing RPMs, can improve the detector response by more than a factor of two relative to an unmodified, bare design. Furthermore, optimisation of the air gap surrounding the helium tubes also improves detector efficiency.

  16. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    OpenAIRE

    F. Meier; D. Scherer; Richters, J.; A. Christen

    2011-01-01

    This research quantifies and discusses atmospheric effects, which alter the radiance observed by a ground-based thermal-infrared (TIR) camera. The TIR camera is mounted on a boom at a height of 125 m above ground on top of a high-rise building in the city of Berlin, Germany (52.4556° N, 13.3200° E) and observes the Earth's surface. The study shows that atmospheric correction of TIR imagery of the three-dimensional (3-D) urban environment acquired in oblique viewing geometry has to account for...

  17. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    Directory of Open Access Journals (Sweden)

    F. Meier

    2010-12-01

    Full Text Available This research quantifies and discusses atmospheric effects that alter the radiance observed by a ground-based thermal-infrared (TIR camera mounted on top of a high-rise building in the city of Berlin, Germany. The study shows that atmospheric correction of ground-based TIR imagery of the three-dimensional (3-D urban environment acquired in oblique viewing geometry has to account for spatial variability of line-of-sight (LOS geometry. We present an atmospheric correction procedure that uses these spatially distributed LOS geometry parameters, the radiative transfer model MODTRAN 5.2 and atmospheric profile data derived from meteorological measurements in the field of view (FOV of the TIR camera. The magnitude of atmospheric effects varies during the analysed 24-hourly period (8 August 2009 and is particularly notable for surfaces showing a strong surface-to-air temperature difference. The differences between uncorrected and corrected TIR imagery reach up to 7.7 K at 12:00. Atmospheric effects are biased up to 4.3 K at 12:00 and up to 0.6 K at 24:00, if non-spatially distributed LOS parameters are used.

  18. Chernobyl radionuclides in the environment: Tracers for the tight coupling of atmospheric, terrestrial, and aquatic geochemical processes

    International Nuclear Information System (INIS)

    Observations of the temporal trend in concentrations of Chernobyl radionuclides in atmospheric, terrestrial, and aquatic reservoirs near Duebendorf (Zurich) aided in quantifying fluxes and transfer velocities from one reservoir to another. Radionuclide dry and wet deposition rates and velocities from the atmosphere, washout from the catchment basins into surface waters, and deposition rates and mechanisms in lakes were determined. The results from these studies were compared to those from earlier observations on the fate of the radionuclides released by bomb tests, from reactor accidents, and from the purposeful tracer experiments in lakes. The results from our observations indicate the extent to which the Chernobyl radionuclides trace the movement of other atmospheric trace contaminants in the environment

  19. Acoustic remote probing of the environment. [atmospheric and underwater acoustic data acquisition

    Science.gov (United States)

    Pijanowski, J. A.

    1978-01-01

    Atmospheric acoustic probes located either at shore locations near the Chesapeake Bay or on large surface buoys could obtain profiles of wind velocity and turbulence and the temperature and humidity of the atmosphere. At or near the buoy locations, underwater probes located on the bottom could be used to profile current velocity, density, and turbulence and also to determine tide level, wave height, spectrum, and direction. The physical parameter profiles at these earth-surface stations could be used with surface observations by satellite. The most obvious use of data from such a network is to verify and calibrate models of energy exchange between the water of the Bay and the atmosphere.

  20. Sample environment issues relevant to the acquisition of inelastic neutron scattering measurements of heterogeneous catalyst samples

    International Nuclear Information System (INIS)

    Refinements to established sample handling issues connected with the acquisition of inelastic neutron scattering (INS) spectra of heterogeneous catalyst samples are described. This involves modification of a reactor and improvements to gas handling apparatus. The latter includes provision of laboratory space and ventilation facilities that are suited to the increasingly wide range of catalytic samples being examined. INS measurements for CO hydrogenation over an iron-based Fischer-Tropsch catalyst recorded using the MARI spectrometer are presented to illustrate the applicability of the new arrangements

  1. Analysis of Aviation Safety Reporting System Incident Data Associated with the Technical Challenges of the Atmospheric Environment Safety Technology Project

    Science.gov (United States)

    Withrow, Colleen A.; Reveley, Mary S.

    2014-01-01

    This study analyzed aircraft incidents in the NASA Aviation Safety Reporting System (ASRS) that apply to two of the three technical challenges (TCs) in NASA's Aviation Safety Program's Atmospheric Environment Safety Technology Project. The aircraft incidents are related to airframe icing and atmospheric hazards TCs. The study reviewed incidents that listed their primary problem as weather or environment-nonweather between 1994 and 2011 for aircraft defined by Federal Aviation Regulations (FAR) Parts 121, 135, and 91. The study investigated the phases of flight, a variety of anomalies, flight conditions, and incidents by FAR part, along with other categories. The first part of the analysis focused on airframe-icing-related incidents and found 275 incidents out of 3526 weather-related incidents over the 18-yr period. The second portion of the study focused on atmospheric hazards and found 4647 incidents over the same time period. Atmospheric hazards-related incidents included a range of conditions from clear air turbulence and wake vortex, to controlled flight toward terrain, ground encounters, and incursions.

  2. Development of a Harsh Environment Gas Sensor Array for Venus Atmospheric Measurements

    Science.gov (United States)

    Makel, D. B.; Carranza, S.

    2015-04-01

    Progress on the development of a compact chemical microsensor array for profiling the chemical composition of the Venus atmosphere and providing gas composition measurements as part of the long lived lander is described.

  3. Plutonium in the environment: key factors related to impact assessment in case of an accidental atmospheric release

    OpenAIRE

    Guétat, Philippe; Moulin, V. M.; Reiller, Pascal E.; Vercouter, T.; Bion, L.,; Fritsch, P; Monfort, M.; Flury-Herard, A.; Comte, A.; Ménétrier, F.; Ansoborlo, Eric; Jourdain, F.; Boucher, L; Vandorpe, F.

    2009-01-01

    This paper deals with plutonium and key factors related to impact assessment. It is based on recent work performed by CEA which summarize the main features of plutonium behaviour from sources inside installations to the environment and man, and to report current knowledge on the different parameters used in models for environmental and radiological impact assessment. These key factors are illustrated through a case study based on an accidental atmospheric release of Pu in a nuclear facility.

  4. Observations of Polar Dynamics in the Mesosphere and Lower Thermosphere from the Polar Environment Atmospheric Research Laboratory

    OpenAIRE

    2013-01-01

    A suite of instruments capable of observing phenomena in the polar mesosphere and lower thermosphere has been established at the Polar Environment Atmospheric Research Laboratory (PEARL) situated in the Canadian high Arctic at Eureka, Nunavut, Canada (80N, 86W). Observations with some instruments started in 2007 but the full suite started operation in 2008.Instruments located at this site include a meteor radar, a Rayleigh lidar, a Spectral Airglow Temperature Imager (SATI), an all sky airglo...

  5. Numerical simulation of chemical processes in helium plasmas in atmosphere environment

    Institute of Scientific and Technical Information of China (English)

    欧阳建明; 郭伟; 王龙; 邵福球

    2005-01-01

    A model is built to study chemical processes in plasmas generated in helium with trace amounts of air at atmospheric pressure or low pressures. The plasma lifetimes and the temporal evolutions of the main charged species are presented. The plasma lifetimes are longer than that in air plasma at atmospheric pressure, but this is not true at low pressures. The electron number density does not strictly obey the exponential damping law in a longer period.

  6. Development of new materials and their testing on in-situ electrical properties in neutron environment

    International Nuclear Information System (INIS)

    The research and development of high performance ceramics related to nuclear energy have become important, especially for fusion reactors. The innovation and application of new nonmetallic inorganic materials are needed in nuclear energy field. There have been many works on Al2O3-base ceramics and their electrical properties. The dielectric property and electric conductivity of ceramics are important for the application to microwave sintering and the radio frequency heating of plasma in nuclear fusion. Silicon nitride is one of the materials for the electrical insulation in fusion reactors. In this paper, the development of Si3N4-base ceramics is summarized. It has been known that the high temperature strength, fracture mechanism, compression creep and oxidation resistance of hot pressed silicon nitride with magnesia are strongly affected by the intergranular phases composed of impurities and additives. The dielectric property and electrical conductivity of Si3N4-base ceramics without irradiation, the in situ test on the electrical conductivity under neutron irradiation, and the possibility of developing new materials by neutron irradiation are reported. (K.I.)

  7. Neutron field characterisation in a high-energy proton-synchrotron environment using bubble detectors

    International Nuclear Information System (INIS)

    During the beam adjustment of high energy accelerator facilities, a significant number of energetic particles impinge on the internal wall of the vacuum chamber thereby causing the production of intense parasitic radiation field, resulting in a short-term radiation exposure to personnel as well as interference in the operation of accelerator instrumentation systems usually based on sophisticated microelectronics. High-energy particle accelerators operate in pulsed mode; therefore, commercially available, general purpose radiation detectors for health physics activities are unsuitable for the assessment of such radiation field due to 'pulse pile-up' effects. Hence, we have used passive neutron dosimeters, i.e. temperature compensated superheated emulsion (bubble) detectors of types BDPND and BDT, to evaluate the neutron fluence at three selected locations of the 7.6 GeV proton synchrotron operated by DESY: (a) the 1.2-m thick concrete shielding roof of the experiment hall housing the proton synchrotron, (b) the 0.9-m thick shielding roof of the proton injector hut, and (c) at the lateral wall (2.5 m concrete and earth shielding) of the experiment hall, facing the proton injector delivering 7.6 GeV protons into the PETRA booster ring

  8. Cosmic-ray neutron spectrometry and dosimetry

    International Nuclear Information System (INIS)

    When primary cosmic rays consisting of galactic cosmic rays and solar particles come into the earth's atmosphere, secondary neutrons generated through nuclear reactions with atmospheric atoms reach the ground. Over the past 10 years, there has been increasing concern about the exposure of air crews to atmospheric cosmic radiation. At aviation altitudes, the neutron component of the secondary cosmic radiation contributes about half of the dose equivalent. Recently, an accumulation of the semiconductor device greatly increases and the soft-errors of SRAM and DRAM on the ground level caused by high-energy cosmic-ray neutrons become a serious problem in the world. Under these circumstances, cosmic-ray neutron spectrometry and dosimetry are presented here in the terrestrial and space environments where neutrons and protons coexist. The neutron detection methods for use in this mixed field are described; 1) multi-moderator spectrometer (Bonner Ball), 2) organic liquid scintillation spectrometer, 3) dose-equivalent counter (rem counter) and 4) Phoswich-type detector. Using these detectors, neutron energy spectra and dose-equivalent rates have been measured on the ground at sea level and at mountain level, aboard an airplane and in space. The space experiments were done using a balloon, space shuttle and space station. The neutron spectrum on the ground has three major peaks, thermal energy peak, evaporation peak around 1 MeV and cascade peak around 100 MeV. While on the other hand, the neutron spectrum apart from the ground has no thermal neutron peak that comes from the albedo neutron effect backscattered from the terrestrial surface. The time-sequential experimental results in Japan, Europe and U.S.A. are described with the experimental procedures by paying attention to variation with latitude, altitude and solar activity. (author)

  9. A neutron diffraction and molecular dynamics investigation of the environment of Dy3+ ions in a fluoroberyllate glass

    International Nuclear Information System (INIS)

    A combined neutron diffraction and molecular dynamics study is reported of the Dy3+ ion environment in vitreous NaF--DyF3--BeF2, using a special version of the isotopic substitution procedure known as the null technique. To investigate the effects of both NaF and DyF3 on the basic beryllium fluoride glass network, complementary measurements and simulations have been performed for vitreous NaF--BeF2, with the same NaF:BeF2 ratio as the DyF3 containing glass, and also for pure vitreous BeF2. The neutron diffraction data indicate that for glasses simulated using pair potentials the BeF4 tetrahedra are much more distorted than those in the real materials and the mean Be--F--Be angle is too high. Both of these deficiencies in the simulations are attributed to the use of simple ionic potentials with no bond angle restoring forces. Experimentally, the distribution of Dy--F first neighbor distances is found to be narrow, having a root mean square deviation of 0.110±0.003 A about the mean value of 2.290±0.003 A. The Dy(F) coordination number is 7.3±0.2 which is slightly less than that in crystalline DyF3

  10. Overview of the projects recently developed by the advanced neutron environment team at the ILL

    Science.gov (United States)

    Bourgeat-Lami, Eric; Chapuis, Jean-François; Chastagnier, Jérémie; Demas, Steffen; Gonzales, Jean-Paul; Keay, Morley-Patrick; Laborier, Jean-Luc; Lelièvre-Berna, Eddy; Losserand, Olivier; Martin, Paul; Mélési, Louis; Petoukhov, Alexander; Pujol, Serge; Ragazzoni, Jean-Louis; Thomas, Frédéric; Tonon, Xavier

    2006-11-01

    Within the framework of the Millennium Programme, we have started the design and building of novel equipment with the aim at facilitating and diversifying the experimental conditions on Institut Laue-Langevin (ILL) and ILL-CRG instruments. We anticipate new devices for applying external parameters (pressure, temperature, magnetic or electric fields, etc.), handling the neutron beam polarisation (RF wide-band flipper, TOF-Cryopad, etc.) or carrying multi-task experiments. The facilities already in operation are briefly reviewed: 3 K cryogen-free cryostat hosting the Paris-Edinburgh pressure cell, 3 K pulse-tube top-loading cryostat with 700 K high-temperature insert, 2 K Joule-Thomson cryogen-free cryostat for Eulerian cradles, 20 mK dilution fridge for the recently acquired 15 T cryomagnet and a low-temperature gas-injection sample stick for Orange cryostats.

  11. Neutronic measurements on electrolytic cells with deuterated palladium in a submarine environment

    International Nuclear Information System (INIS)

    Using a high efficiency system for the neutron thermal detection and a pulsed electrolytic current procedure, measurements were made on cells containing Pd cathodes and electrolytes at a D2O and H2O base. The peculiarity of these experiments is that they were carried out on board of the A.R.A. Santa Cruz submarine, at a depth of 50m under sea level, attaining ultra deep-down conditions in the measurements, corresponding to a reduction in a factor = 50 in relation to lab conditions. The mean level of the signal -obtained from counting combination of deuterated cathodes- results to be separated from the deep-down level by four standard deviations. (Author)

  12. Rare earth elements determination and distribution patterns in sediments of polluted marine environment by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Results obtained from the analysis of sediment core samples taken from a fairly polluted marine environment were analyzed for the REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy and Yb using instrumental neutron activation analysis. Core samples were divided into strata of between 2 to 3 cm intervals and prepared in the powdered form before irradiating them in a TRIGA Mk.II reactor. Down-core concentration profiles of La, Ce, Sm, Eu, Tb, Dy and Yb in 3 core sediments from three sites are obtained. The shale-normalized REE pattern from each site was examined and later used to explain the history of sedimentation by natural processes such as shoreline erosion and weathering products deposited on the seabed and furnishing some baseline data and/or pollution trend occurring within the study area

  13. Improving FermiI Orbit Determination and Prediction in an Uncertain Atmospheric Drag Environment

    Science.gov (United States)

    Vavrina, Matthew A.; Newman, Clark Patrick; Slojkowski, Steven E.; Carpenter, J. Russell

    2014-01-01

    Orbit determination and prediction of the Fermi Gamma-ray Space Telescope trajectory is strongly impacted by the unpredictability and variability of atmospheric density and the spacecrafts ballistic coefficient. Operationally, Global Positioning System point solutions are processed with an extended Kalman filter for orbit determination, and predictions are generated for conjunction assessment with secondary objects. When these predictions are compared to Joint Space Operations Center radar-based solutions, the close approach distance between the two predictions can greatly differ ahead of the conjunction. This work explores strategies for improving prediction accuracy and helps to explain the prediction disparities. Namely, a tuning analysis is performed to determine atmospheric drag modeling and filter parameters that can improve orbit determination as well as prediction accuracy. A 45 improvement in three-day prediction accuracy is realized by tuning the ballistic coefficient and atmospheric density stochastic models, measurement frequency, and other modeling and filter parameters.

  14. Improving Fermi Orbit Determination and Prediction in an Uncertain Atmospheric Drag Environment

    Science.gov (United States)

    Vavrina, Matthew A.; Newman, Clark P.; Slojkowski, Steven E.; Carpenter, J. Russell

    2014-01-01

    Orbit determination and prediction of the Fermi Gamma-ray Space Telescope trajectory is strongly impacted by the unpredictability and variability of atmospheric density and the spacecraft's ballistic coefficient. Operationally, Global Positioning System point solutions are processed with an extended Kalman filter for orbit determination, and predictions are generated for conjunction assessment with secondary objects. When these predictions are compared to Joint Space Operations Center radar-based solutions, the close approach distance between the two predictions can greatly differ ahead of the conjunction. This work explores strategies for improving prediction accuracy and helps to explain the prediction disparities. Namely, a tuning analysis is performed to determine atmospheric drag modeling and filter parameters that can improve orbit determination as well as prediction accuracy. A 45% improvement in three-day prediction accuracy is realized by tuning the ballistic coefficient and atmospheric density stochastic models, measurement frequency, and other modeling and filter parameters.

  15. Meteorological influences on atmospheric radioactivity and its effects on the electrical environment

    International Nuclear Information System (INIS)

    The 222Rn content of soil gas is influenced by meteorological parameters and especially by wind speed. For 220Rn the effects are less pronounced. The exhalation of 220Rn is dependent on precipitation and atmospheric turbulence. From horizontal measurements of radioactivity in the air, the most representative values are obtained under unstable, near-neutral, and light stable stratifications. The concentration of natural radioactivity at a point in the atmospheric surface layer can be expressed in terms of atmospheric stability if the horizontal distributions are fairly homogeneous. For longtime variations of radioactivity in the air, the precipitation and groundwater conditions are of prime concern. But for the rapid fluctuations the turbulent processes give the main contribution to the variations

  16. Neutron Capture Nucleosynthesis

    OpenAIRE

    Kiss, Miklos

    2016-01-01

    Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these resu...

  17. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    Directory of Open Access Journals (Sweden)

    I. Salma

    2010-06-01

    Full Text Available Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6–1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8×103 to 29×103 cm−3 with a yearly median of 11.8×103 cm−3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79±6%. Daily average number concentrations in various size fractions and contribution of ultrafine particles to the total particle number showed no seasonal dependency. Monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. Median diameters of the Aitken and accumulation modes were shifted to larger values before nucleation started and over the growth process, which can be related to the presence of aged aerosol under the conditions that favour nucleation and growth. Particle concentrations were usually increased substantially after nucleations. Overall mean and standard deviation of the nucleation mode number concentrations were (10.4±2.8×103 cm−3. Mean ratio and standard deviation of the nucleation mode number concentration to the total particle number concentration that was averaged for two hours just before the formation was detected was 2.3±1.1. Nucleation unambiguously occurred on 83 days, which represent 27% of all relevant days. Its frequency showed a

  18. Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

    Directory of Open Access Journals (Sweden)

    I. Salma

    2011-02-01

    Full Text Available Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6–1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8 × 103 to 29 ×103 cm−3 with a yearly median of 11.8 × 103 cm−3. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79 ± 6%. Typical diurnal variation of the particle number concentration was related to the major emission patterns in cities, new particle formation, sinks of particles and meteorology. Shapes of the monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. New particle formation and growth unambiguously occurred on 83 days, which represent 27% of all relevant days. Hence, new particle formation and growth are not rare phenomena in Budapest. Their frequency showed an apparent seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. New particle formation events were linked to increased gas-phase H2SO4 concentrations. In the studied area, new particle formation is mainly affected by condensation sink and solar radiation. The formation process seems to be not sensitive to SO2, which was present in a yearly median concentration of 6.7 μg m−3. This suggests that the precursor gas was always available in excess

  19. Remote sensing of the earth's biosphere - A tool for studies of the global atmospheric environment

    Science.gov (United States)

    Bartlett, David S.; Harriss, Robert C.; Bartlett, Karen B.

    1987-01-01

    Recent advances in remote sensing technology and its use for global studies of the biospheric processes are described. Special consideration is given to research related to two issues: (1) quantifying the impacts of natural vegetation and its changing patterns of occurrence on the atmospheric CO2 budget and (2) assessing wetlands (such as the swamps and marshes of Florida's Everglades) as sources of atmospheric CH4. The results include the data from NOAA-AVHRR sensors and from experiments in remote detection of plant growth rate.

  20. Cosmic-ray neutron simulations and measurements in Taiwan

    International Nuclear Information System (INIS)

    This study used simulations of galactic cosmic ray in the atmosphere to investigate the neutron background environment in Taiwan, emphasising its altitude dependence and spectrum variation near interfaces. The calculated results were analysed and compared with two measurements. The first measurement was a mobile neutron survey from sea level up to 3275 m in altitude conducted using a car-mounted high-sensitivity neutron detector. The second was a previous measured result focusing on the changes in neutron spectra near air/ground and air/water interfaces. The attenuation length of cosmic-ray neutrons in the lower atmosphere was estimated to be 163 g cm-2 in Taiwan. Cosmic-ray neutron spectra vary with altitude and especially near interfaces. The determined spectra near the air/ground and air/water interfaces agree well with measurements for neutrons below 10 MeV. However, the high-energy portion of spectra was observed to be much higher than our previous estimation. Because high-energy neutrons contribute substantially to a dose evaluation, revising the annual sea-level effective dose from cosmic-ray neutrons at ground level in Taiwan to 35 μSv, which corresponds to a neutron flux of 5.30 x 10-3 n cm-2 s-1, was suggested. The cosmic-ray neutron background in Taiwan was studied using the FLUKA simulations and field measurements. A new measurement was performed using a car-mounted high-efficiency neutron detector, re-coding real-time neutron counting rates from sea level up to 3275 m. The attenuation of cosmic-ray neutrons in the lower atmosphere exhibited an effective attenuation length of 163 g cm-2. The calculated neutron counting rates over predicted the measurements by ∼32 %, which leaded to a correction factor for the FLUKA-calculated cosmic-ray neutrons in the lower atmosphere in Taiwan. In addition, a previous measurement regarding neutron spectrum variation near the air/ground and air/water interfaces was re-evaluated. The results showed that the amount of

  1. The Polluted Atmosphere of the White Dwarf NLTT 25792 and the Diversity of Circumstellar Environments

    Czech Academy of Sciences Publication Activity Database

    Vennes, Stephane; Kawka, Adela

    2013-01-01

    Roč. 779, č. 1 (2013), 70/1-70/10. ISSN 0004-637X R&D Projects: GA ČR GA13-14581S; GA ČR GAP209/12/0217 Institutional support: RVO:67985815 Keywords : stars * abundances * atmospheres Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.280, year: 2013

  2. Energy, Atmosphere, and Climate. Teacher's Guide to World Resources. Comprehensive Coursework on the Global Environment.

    Science.gov (United States)

    Snyder, Sarah A.

    This teacher's guide presents teaching suggestions and presentation materials about how daily human activities, such as energy use, add pollutants to the atmosphere. The lesson is divided into seven parts and can be taught in two or more class periods. Student handouts include: (1) "Total Energy Use by Fuel Type, 1991"; (2) "Facts about Air…

  3. Genetic Variation for Shelf-life of Salad-cut Lettuce in Modified-atmosphere Environments

    Science.gov (United States)

    Minimally processed lettuce (Lactuca sativa L.) is an important component of the lettuce industry. The product is highly perishable; cold storage and modified atmosphere (MA) packaging are used to extend its shelf-life. Given the importance of this market, lettuce cultivars, breeding lines, and pop...

  4. Mechanical properties of neutron irradiated vanadium alloys under liquid sodium environment

    International Nuclear Information System (INIS)

    Full text of publication follows: Vanadium alloys are candidate materials for fusion reactor blanket structural materials, but its knowledge about the mechanical properties at high temperatures during neutron irradiation is limited and there are uncertainties that may have influenced the results such as the interstitial impurity content of specimens. The objective of this study is to investigate the mechanical properties and microstructural changes of the high-purified V-4Cr-4Ti alloys, NIFS-HEAT2 during neutron irradiation. In this study, tensile test, Charpy impact test and microstructural observation were done for V-4Cr-4Ti alloys and vanadium binary alloys. Small sized tensile specimens, 1.5 Charpy V-notched specimens and TEM specimens of highly purified V-4Cr-4Ti alloys, NIFS-Heat and vanadium binary alloys were irradiated in Joyo in the temperature range from 450 deg. C to 650 deg. C with a damage level from 1 to 5 dpa. In the irradiation experiment, we have developed Na-enclosed irradiation rig in Joyo in order to equalize the irradiation temperature of large scale specimens and prevent the invasion of interstitial impurities from the circumstance in irradiation rig during irradiation for irradiation specimens. After dismantling the Na-enclosed capsule and cleaning the surface of specimens, tensile tests at room temperature, Charpy impact tests and TEM observation were performed. Irradiation hardening and reduction of ductility for NIFS-Heat alloys could be seen at 450 deg. C irradiation in tensile tests, but the destructive loss of plasticity could not be in any vanadium specimens even at 450 deg. C irradiation. Results of Charpy impact test showed that the amounts of upper shelf energy of NIFS-heat specimens irradiated at 450 deg. C and 600 deg. C were about 0.1-0.2 J at room temperature and brittle behavior could not be seen from load displacement relationship and SEM observation of fracture surface. From the TEM observation of NIFS-Heat alloys

  5. Assessment of atmospheric assimilation potential for industrial development in an urban environment. Kochi (India)

    International Nuclear Information System (INIS)

    The assimilation potential (assimilative capacity) of the atmosphere can be represented in two ways: one as the ventilation coefficient and the other as the dispersion potential of emission loads discharged into the region. In the present study, the atmospheric assimilation potential of a typical urban area in Kochi city has been determined with respect to sulfur dioxide (SO2). The ventilation coefficient is directly proportional to the assimilation potential of the atmosphere and has been computed using meteorological parameters in all four seasons (winter, summer, monsoon and post-monsoon) of the years 1998-1999 represented by January, April, July and October respectively. The diurnal variation in ventilation coefficients shows that the assimilative capacity of the atmosphere is high during the afternoon and is reduced during the evening and morning in all the seasons. Among all the seasons, monsoon and post-monsoon have the poorest assimilative capacity throughout the day. In the second approach, the assimilation potential is estimated through dispersion modelling in terms of the concentration of pollutants, which is inversely proportional to the assimilative capacity of the atmosphere. The Industrial Source Complex (ISC) dispersion model for point sources has been used to predict the spatial and temporal distribution of SO2 under three different industrial scenarios (type of industries existing in the Kochi region, refinery and power plant). The model predictions indicate that monsoon is the most critical season having maximum pollution, followed by summer and post-monsoon. Lowest pollution was observed in winter. The assimilative capacity in terms of the ventilation coefficient is very poor indicating high pollution potential in all the seasons. However, dispersion modeling suggests that if industrial development is planned properly, additional industrial sources can be accommodated by restricting the emission loads to be within the assimilation potential of

  6. The Third Pole Environment Programme (TPE): A new base for the processes study of atmospheric physics and environment over the Tibetan Plateau and surrounding regions

    Science.gov (United States)

    Ma, Yaoming

    2016-04-01

    The Tibetan Plateau, with the most prominent and complicated terrain on the globe and an elevation of more than 4000 m on average above sea leave (msl), is often called the "Third Pole" due to its significance parallel with Antarctica and the Arctic. The exchange of energy, water vapor and some greenhouse gases between land surface and atmosphere over the Tibetan Plateau and the surrounding regions play an important role in the Asian monsoon system, which in turn is a major component of both the energy and water cycles of the global climate system. Supported by the Chinese Academy of Sciences and some international organizations, a Third Pole Environment (TPE) Research Platform (TPEP) is now implementing over the Tibetan Plateau and surrounding region. The background of the establishment of the TPEP, the establishing and monitoring plan of long-term scale (5-10 years) of the TPEP will be shown firstly. Then the preliminary observational analysis results, such as the characteristics of land surface heat fluxes, CO2 flux and evapotranspiration (ET) partitioning (diurnal variation, inter-monthly variation and vertical variation etc), aerosol optical properties between southern and northern sides of the Himalayas, the characteristics of atmospheric and soil variables, the structure of the Atmospheric Boundary Layer (ABL) and the turbulent characteristics have also been shown in this study.

  7. Swelling of advanced austenitic stainless steels developed for the environment of heavy neutron exposure

    International Nuclear Information System (INIS)

    Modified Type-316 and higher-nickel advanced austenitic steels were irradiated in the FFTF and JOYO fast reactors to a neutron dose as high as 210 dpa. At temperatures greater than 500 C, P-, Si-, and Ti-bearing cold-worked austenitic steels showed significant swelling suppression even after 150 dpa. The dominant mechanism is associated with formation of stable phosphide precipitated by addition of Ti and/or increased Si. In the lower-temperature regime, where the phosphide precipitate is not present, silicon acts to suppress swelling at contents of about 0.8 wt%. Only at this higher silicon level, increased amounts of nickel reduced the swelling. At 0.5 wt% silicon, the swelling was insensitive to the alloying elements, such as Ni, Ti and P. The effect of Si and Ni could be explained by their influence on void nucleation through effects on effective vacancy diffusion coefficient. Further improvement in swelling was expected by increasing the nickel and possibly the phosphorus contents of the advanced austenitics. ((orig.))

  8. Development of an elemental tracer using neutron activation analysis for application in an estuarine environment

    International Nuclear Information System (INIS)

    Selection of an activable tracer that could be used to study dispersion patterns in an English estuary is described and was carried out in connection with the development and testing of a particle-tracking computer model. Understanding estuarine dynamics will assist in the decision-making process for estuarine management and in contingency planning. Neutron activation analysis (NAA) has been used to characterize the concentration and natural variation of 40 trace elements in suspended particulate matter and inter-tidal bed sediment in order to identify a suitable tracer. Results have shown that europium, terbium and ytterbium would be suitable to use in a tracer study as they have low background concentrations in sediments and little variability, (Eu: 1.31 mg x kg-1±13%, Tb: 0.90 mg x kg-1±16% and Yb: 2.91 mg x kg-1±18%). The ratios of these elements are constant throughout the estuary and experiments have shown that increases in concentration of any of these elements due to the addition of artificial elemental tracer could be quantitatively determined by changes in the ratio constant. (author)

  9. Considerations on neutron/environment characteristics in inertial fusion ignition (NIF) and reactor (KOYO) facilities

    International Nuclear Information System (INIS)

    This paper reviews reported calculations on the assessment of some environmental questions related to neutron activation in ignition (national ignition facility, NIF) and reactor (KOYO project) inertial fusion facilities. NIF results on the availability of the target chamber after different gain shots, inventories of activated gases in the bay area, and comments on radiological impacts from normal operations have shown the good environmental qualifications of this facility. The laser fusion conceptual reactor KOYO, developed by the ILE Osaka, uses liquid LiPb film protection flowing through ceramic SiC-base porous tubes in two different packing fraction blankets. It is shown the availability of a large fraction of the SiC with impurities to be considered as class C shallow land burial (SLB); however, the complete solution for SLB is the use of porous woven graphite (C) fabric tubes. An important effect in the activation of the chamber wall, composed by the ferritic steel HT-9, is demonstrated by using an intermediate graphite reflector. A good activation performance in the chamber is demonstrated allowing SLB and different recycling options. Hypothetical environmental releases of 1 kg of target-emissions-facing SiC tubes and HT-9 materials have also been simulated indicating optimum performances. (orig.)

  10. Applications of TMD pulsed neutron logs in unusual downhole logging environments

    International Nuclear Information System (INIS)

    The Welex Thermal Multigate Decay logging system utilizes a pulsed 14 MeV neutron generator and two gamma ray detectors to obtain measurements of the capture cross sections of downhole formations. The composite decay curve from both formation and borehole capture ganna rays is detected, and is separated into the two individual components. The paper begins with a brief review of the TMD logging system with emphasis on the physical significance of all the quality control and new support curves. The bulk of the paper is then placed on log examples in unusual borehole conditions: logs run across intervals where borehole conditions change; logs run in air filled boreholes; logs run in badly washed out boreholes; logs run through stuck drill pipe/collars; logs run in flowing wells. The supplemental TMD curves in these situations identify the presence of gravel packs and packers, changes in borehole fluid salinity, possible communication between zones, and water and oil producing perforations. Gas in the borehole can also be differentiated from gas in the formation

  11. Neutron activation analysis capability of natural objects' estimation for Latvian environment

    International Nuclear Information System (INIS)

    A review of literature data and the NAA techniques developed by the authors for the analysis of environmental saples (aerosols, fly ash, soil, pine needls, natural and technological waters) are presented. The methods are used for the routine analysis of some samples from the environment of industrial and power plants of Latvia to investigate and control the local pollution with heavy metals, arsenic, halogens

  12. Neutron Capture Nucleosynthesis

    CERN Document Server

    Kiss, Miklos

    2016-01-01

    Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

  13. Kinetics of atmospheric corrosion of mild steel in marine and rural environments

    Science.gov (United States)

    Palraj, S.; Selvaraj, M.; Maruthan, K.; Natesan, M.

    2015-03-01

    In continuation of the extensive studies carried out to update the corrosion map of India, in this study, the degradation of mild steel by air pollutants was studied at 16 different locations from Nagore to Ammanichatram along the east coast of Tamilnadu, India over a period of two years. The weight loss study showed that the mild steel corrosion was more at Nagapattinam site, when compared to Ammanichatram and Maravakadu sites. A linear regression analysis of the experimental data was attempted to predict the mechanism of the corrosion. The composition of the corrosion products formed on the mild steel surfaces was identified by XRD technique. The corrosion rate values obtained are discussed in the light of the weathering parameters, atmospheric pollutants such as salt content & SO2 levels in the atmosphere, corrosion products formed on the mild steel surfaces.

  14. Kinetics of Atmospheric Corrosion of Mild Steel in Marine and Rural Environments

    Institute of Scientific and Technical Information of China (English)

    S. Palraj; M.Selvaraj; K.Maruthan; M.Natesan

    2015-01-01

    In continuation of the extensive studies carried out to update the corrosion map of India, in this study, the degradation of mild steel by air pollutants was studied at 16 different locations from Nagore to Ammanichatram along the east coast of Tamilnadu, India over a period of two years. The weight loss study showed that the mild steel corrosion was more at Nagapattinam site, when compared to Ammanichatram and Maravakadu sites. A linear regression analysis of the experimental data was attempted to predict the mechanism of the corrosion. The composition of the corrosion products formed on the mild steel surfaces was identified by XRD technique. The corrosion rate values obtained are discussed in the light of the weathering parameters, atmospheric pollutants such as salt content & SO2 levels in the atmosphere, corrosion products formed on the mild steel surfaces.

  15. Determination of elements in the atmosphere of Valle de Toluca by Neutron Activation (July 1992 - April 1993)

    International Nuclear Information System (INIS)

    The purpose of this study is to continue with the environmental monitoring program of Valle de Toluca by means of the Neutron Activation Analysis and atomic absorption techniques. The analytical results corresponding to the period of July 1992 to April 1993, and the analyzed elements by Neutron Activation were Na, V, Br, Al and Mn, while Cr and Pb were analyzed by Atomic Absorption Spectroscopy. Since the study is a joint project with the Facultad de Quimica de la Universidad Autonoma del Estado de Mexico, the purpose is to continue with this type of chemical analysis. (Author)

  16. The Atmospheric Corrosion of Magnesium Alloys : Influence of Microstructure and Environments

    OpenAIRE

    Jönsson, Martin

    2007-01-01

    The low density and high specific strength of magnesium alloys have created a great deal of interest in the use of these alloys in the automotive and aerospace industries and in portable electronics. All of these industries deal with applications in which weight is extremely important. However, an obstacle to overcome when using magnesium alloys in engineering applications are their unsatisfactory corrosion properties. This thesis is devoted to the atmospheric corrosion of the two magnesium a...

  17. WINTER ATMOSPHERIC PHENOMENA AND THEIR IMPACT ON THE ENVIRONMENT IN THE AREA OF ORADEA

    OpenAIRE

    Aurelia Florina Dumiter

    2008-01-01

    The paper presents the manifestation of the main atmospheric winter phenomena in the area of Oradea. There have been studied, interpreted and analyzed daily, monthly and annual data regarding the hoarfrost , the ice coatings and the blizzard, during the period 1961-2003, in the area of Oradea, registered at the ANM network weather station, in addition, a study case regarding the ice coatings is presented.

  18. Defining the Natural Atmospheric Environment Requirements for the NASA Constellation Program

    Science.gov (United States)

    Roberts, Barry C.; Leahy, Frank

    2008-01-01

    The National Aeronautics and Space Administration began developing a new vehicle under the Constellation Program to replace the Space Shuttle. The Ares-1 launch vehicle and the Orion capsule will be used to ferry crew and some payloads to the International Space Station and will also be used for new missions to the moon, As development of this new vehicle begins, the Natural Environments Branch at Marshall Space Flight Center has been tasked with defining the natural environments the vehicle will encounter and working with the program to develop natural environmental requirements for the vehicles' elements. An overview of the structure of the program is given, along with a description of the Constellation Design Specification for Natural Environments and the Constellation Natural Environments Definition for Design documents and how they apply to the Ares-I and Orion vehicles.

  19. Venus high temperature atmospheric dropsonde and extreme-environment seismometer (HADES)

    Science.gov (United States)

    Boll, Nathan J.; Salazar, Denise; Stelter, Christopher J.; Landis, Geoffrey A.; Colozza, Anthony J.

    2015-06-01

    The atmospheric composition and geologic structure of Venus have been identified by the US National Research Council's Decadal Survey for Planetary Science as priority targets for scientific exploration; however, the high temperature and pressure at the surface, along with the highly corrosive chemistry of the Venus atmosphere, present significant obstacles to spacecraft design that have severely limited past and proposed landed missions. Following the methodology of the NASA Innovative Advanced Concepts (NIAC) proposal regime and the Collaborative Modeling and Parametric Assessment of Space Systems (COMPASS) design protocol, this paper presents a conceptual study and initial feasibility analysis for a Discovery-class Venus lander capable of an extended-duration mission at ambient temperature and pressure, incorporating emerging technologies within the field of high temperature electronics in combination with novel configurations of proven, high Technology Readiness Level (TRL) systems. Radioisotope Thermal Power (RTG) systems and silicon carbide (SiC) communications and data handling are examined in detail, and various high-temperature instruments are proposed, including a seismometer and an advanced photodiode imager. The study combines this technological analysis with proposals for a descent instrument package and a relay orbiter to demonstrate the viability of an integrated atmospheric and in-situ geologic exploratory mission that differs from previous proposals by greatly reducing the mass, power requirements, and cost, while achieving important scientific goals.

  20. Venus High Temperature Atmospheric Dropsonde and Extreme-Environment Seismometer (HADES)

    Science.gov (United States)

    Boll, Nathan J.; Salazar, Denise; Stelter, Christopher J.; Landis, Geoffrey A.; Colozza, Anthony J.

    2014-01-01

    The atmospheric composition and geologic structure of Venus have been identified by the US National Research Council's Decadal Survey for Planetary Science as priority targets for scientific exploration, however the high temperature and pressure at the surface, along with the highly corrosive chemistry of the Venus atmosphere, present significant obstacles to spacecraft design that have severely limited past and proposed landed missions. Following the methodology of the NASA Innovative Advanced Concepts (NIAC) proposal regime and the Collaborative Modeling and Parametric Assessment of Space Systems (COMPASS) design protocol, this paper presents a conceptual study and initial feasibility analysis for a Discovery-class Venus lander capable of an extended-duration mission at ambient temperature and pressure, incorporating emerging technologies within the field of high temperature electronics in combination with novel configurations of proven, high Technology Readiness Level (TRL) systems. Radioisotope Thermal Power (RTG) systems and silicon carbide (SiC) communications and data handling are examined in detail, and various high-temperature instruments are proposed, including a seismometer and an advanced photodiode imager. The study combines this technological analysis with proposals for a descent instrument package and a relay orbiter to demonstrate the viability of an integrated atmospheric and in-situ geologic exploratory mission that differs from previous proposals by greatly reducing the mass, power requirements, and cost, while achieving important scientific goals.

  1. Atmospheric Water Soluble Organic Nitrogen (WSON) over marine environments: a global perspective

    Science.gov (United States)

    Violaki, K.; Sciare, J.; Williams, J.; Baker, A. R.; Martino, M.; Mihalopoulos, N.

    2014-07-01

    To obtain a comprehensive picture on the spatial distribution of water soluble organic nitrogen (WSON) in marine aerosols, samples were collected during research cruises in the tropical and south Atlantic Ocean and during a one year period (2005) over the southern Indian Ocean (Amsterdam island). Samples have been analyzed for both organic and inorganic forms of nitrogen and the factors controlling their levels have been examined. Fine mode WSON was found to play a significant role in the remote marine atmosphere with enhanced biogenic activity, with concentrations of WSON (11.3 ± 3.3 nmol N m-3) accounting for about 84% of the total dissolved nitrogen (TDN). Such levels are similar to those observed in the polluted marine atmosphere of the eastern Mediterranean (11.6 ± 14.0 nmol N m-3). Anthropogenic activities were found to be an important source of atmospheric WSON as evidenced by the ten times higher levels in the Northern Hemisphere (NH) than in the remote Southern Hemisphere (SH). Furthermore, the higher contribution of WSON to TDN (40%) in the SH, compared to the NH (20%), underlines the important role of organic nitrogen in remote marine areas. Finally, Sahara dust was also identified as a significant source of WSON in the coarse mode aerosols of the NH.

  2. Atmospheric water-soluble organic nitrogen (WSON) over marine environments: a global perspective

    Science.gov (United States)

    Violaki, K.; Sciare, J.; Williams, J.; Baker, A. R.; Martino, M.; Mihalopoulos, N.

    2015-05-01

    To obtain a comprehensive picture of the spatial distribution of water-soluble organic nitrogen (WSON) in marine aerosols, samples were collected during research cruises in the tropical and southern Atlantic Ocean and also in the southern Indian Ocean (Amsterdam Island) for a 1-year period (2005). Samples were analyzed for both organic and inorganic forms of nitrogen, and the factors controlling their levels were examined. Fine-mode WSON was found to play a significant role in the remote marine atmosphere with enhanced biogenic activity, with concentrations of WSON (11.3 ± 3.3 nmol N m-3) accounting for about 84 % of the total dissolved nitrogen (TDN). Such concentrations are similar to those observed in the polluted marine atmosphere of the eastern Mediterranean (11.6 ± 14.0 nmol N m-3). Anthropogenic activities were found to be an important source of atmospheric WSON as evidenced by the levels in the Northern Hemisphere (NH) being 10 times higher than in the remote Southern Hemisphere (SH). Furthermore, the higher contribution of fine-mode WSON to TDN (51%) in the SH, compared to the NH (13%), underlines the important role of organic nitrogen in remote marine areas. Finally, there was a strong association of WSON with dust in coarse-mode aerosols in the NH.

  3. Atmospheric contamination

    International Nuclear Information System (INIS)

    It is about the levels of contamination in center America, the population's perception on the problem, effects of the atmospheric contamination, effects in the environment, causes of the atmospheric contamination, possibilities to reduce the atmospheric contamination and list of Roeco Swisscontac in atmospheric contamination

  4. The study on human health and environment by neutron activation analysis of biological samples

    International Nuclear Information System (INIS)

    - Choice of samples for the research goal and survey of individual food habit and sampling for the meaningful statistical output - Development of the optimum analytical method for the analysis of trace elements in biological samples such as hair, blood, and foods. - Quantitative analysis of several samples to identify the source of trace elements into human body. - Evaluation in view of health and environment to the trace elements in various sources which can be introduced inside human body

  5. Rare earth elements determination and distribution patterns in sediments of a polluted marine environment by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Results obtained from the analysis of sediment core samples taken from a fairly polluted marine environment were analyzed for the REE contents to determine the concentrations of La, Ce, Sm, Eu, Tb, Dy and Yb using instrumental neutron activation analysis. Core samples were divided into strata of between 2 to 3 cm intervals and prepared in the powdered form before irradiating them in a neutron flux of about 5.0 x 1012 n x cm-2 x s-1 in a Triga Mark II reactor. Down-core concentration profiles of La, Ce, Sm, Eu, Tb, Dy and Yb in 3 core sediments from three sites are obtained. The shale-normalized REE pattern from each site was examined and later used to explain the history of sedimentation by natural processes such as shoreline erosion and weathering products deposited on the seabed and furnishing some baseline data and/or pollution trend occurring within the study area. The shale-normalized REE patterns also showed that LREE in the sediment samples exhibit enrichment relative to HREE particularly, La and Sm showing enrichment compared to the ratios in shale. REE concentrations of 124 μg/g at the surface of sediment collected at two of the three sites were found to decrease to 58 and 95 μg/g, respectively. This was of particular interest when it is used to explain the anomalies occurring in the marine sediment as a result of geochemical processes over a long period of time. Changes in concentrations from surface to bottom of the sediments ratioed to Sm concentrations and the correlation between concentrations of Sm and these elements were also investigated and correlation coefficients were calculated for all REEs and sites. Validation of the method used was done using a Soil-7 SRM. (author)

  6. Neutron Capture and the Production of 60-Fe in Stellar Environments

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, K

    2005-08-23

    The observation of gamma rays associated with the decay of {sup 26}Al and {sup 60}Fe can provide important information regarding ongoing nucleosynthesis in our galaxy. The half-lives of these radioisotopes (7.2 x 10{sup 5} y and 1.5 x 10{sup 6} y, respectively) are long compared to the interval between synthesis events such as supernovae, so they build up in a steady state in the interstellar medium (centered on the galactic plane, where massive stars reside), yet short enough that gamma radiation from their decay may be detected. Additionally, these half-lifes are short compared to the period of galactic revolution, so that observable abundances remain in the proximity of their production sites. Predicted abundances of {sup 26}Al and {sup 60}Fe vary widely between several calculations in the last decade. In 2004, the first observation of the gamma ray flux from {sup 60}Fe decay was reported, with a {sup 60}Fe/{sup 26}Al flux ratio in good agreement with nucleosynthesis modeling from 1995. However, recent calculations that include well motivated updates to the stellar and nuclear physics, predict a flux ratio as much as six times higher than the observed value. It is desirable to understand the discrepancy between the latest calculation, which in principle should have been more accurate, and the observation. In the present study, the uncertainties related to two key nuclear aspects of this problem, namely the neutron capture reaction rates for {sup 59,60}Fe, are investigated. New reaction rates are modeled using local systematics as opposed to the global systematics used in previous studies. Comparisons to experimental data are made whenever possible. The sensitivity of the reaction rates to various input quantities is gauged, and estimates regarding the total uncertainty in the reaction rates are made. The resulting rates and uncertainties are used in parameterized single-zone nucleosynthesis calculations using hydrodynamic conditions typical of those found in

  7. Physicochemical and Toxicological Characteristics of Semi-volatile Components of Atmospheric Aerosols in an Urban Environment

    Science.gov (United States)

    Verma, V.; Pakbin, P.; Cheung, K. L.; Cho, A. K.; Schauer, J. J.; Shafer, M. M.; Kleinman, M. T.; Sioutas, C.

    2010-12-01

    Recent toxicological studies have confirmed the oxidative properties of atmospheric aerosols and their capability to generate reactive oxygen species (ROS) in biological systems (Chen and Lippmann, 2009). While the links between aerosol toxicity and refractory transition metals present in ambient particulate matter (PM) have been documented, there are limited studies investigating the oxidative characteristics of semi-volatile species. The goal of present study is to examine the contribution of semi-volatile compounds in the oxidative potential of atmospheric aerosols. Concentrated ambient and thermodenuded quasi-ultrafine particles (dithiothreitol) assay. Detailed chemical analyses of PM samples, including organic and elemental carbon, water soluble elements, inorganic ions and polycyclic aromatic hydrocarbons (PAHs), were conducted to quantify the volatility profiles of different PM species, and also to investigate their effect on the measured oxidative potential. Refractory constituents, such as metals and elemental carbon, were marginally affected by heating, while labile species such as organic carbon and PAHs showed progressive loss in concentration with increase in TD temperature. The DTT-measured oxidative potential of PM was significantly decreased as the aerosols were heated and their semi-volatile components were progressively removed (42 %, 47 % and 66 % decrease in DTT activity at 50, 100 and 200 oC, respectively). Regression analysis performed between chemical constituents and DTT activity showed that the oxidative potential was strongly correlated with organic carbon and PAHs (R≥0.80; p≤0.05). Thus, semi-volatile organic compounds present in atmospheric aerosols constitute a substantial fraction of the PM oxidative potential, which is largely responsible for the aerosol toxicity. References: Chen, L.C., Lippmann, M., 2009. Effects of metals within ambient air particulate matter (PM) on human health. Inhalation Toxicology 21 (1), 1-31.

  8. Examination of geostatistical and machine-learning techniques as interpolators in anisotropic atmospheric environments

    Science.gov (United States)

    Tadić, Jovan M.; Ilić, Velibor; Biraud, Sebastien

    2015-06-01

    Selecting which interpolation method to use significantly affects the results of atmospheric studies. The goal of this study is to examine the performance of several interpolation techniques under typical atmospheric conditions. Several types of kriging and artificial neural networks used as spatial interpolators are here compared and evaluated against ordinary kriging, using real airborne CO2 mixing-ratio data and synthetic data. The real data were measured (on December 26, 2012) between Billings and Lamont, near Oklahoma City, Oklahoma, within and above the planetary boundary layer (PBL). Predictions were made all along the flight trajectory within a total volume of 5000 km3 of atmospheric air (27 × 33 × 5.6 km). We evaluated (a) universal kriging, (b) ensemble neural networks, (c) universal kriging with ensemble neural network outputs used as covariates, and (d) ensemble neural networks with ordinary kriging of the residuals as interpolation tools. We found that in certain cases, when the weaknesses of ordinary kriging interpolation schemes (based on an omnidirectional isotropic variogram presumption) became apparent, more sophisticated interpolation methods were in order. In this study, preservation of the potentially nonlinear relationship between the trend and coordinates (by using neural kriging output as a covariate in a universal kriging scheme) was attempted, with varying degrees of success (it was best performer in 4 out of 8 cases). The study confirmed the necessity of selecting an interpolation approach that includes a combination of expert understanding and appropriate interpolation tools. The error analysis showed that uncertainty representations generated by the kriging methods are superior to neural networks, but that the actual error varies from case to case.

  9. Transport of tritium contamination to the atmosphere in an arid environment

    Science.gov (United States)

    Garcia, C.A.; Andraski, B.J.; Stonestrom, D.A.; Cooper, C.A.; Johnson, M.J.; Michel, R.L.; Wheatcraft, S.W.

    2009-01-01

    Soil-plant-atmosphere interactions strongly infl uence water movement in desert unsaturated zones, but litile is known about how such interactions aff ect atmospheric release of subsurface water-borne contaminants. This 2-yr study, performed at the U.S. Geological Survey's Amargosa Desert Research Site in southern Nevada, quantifi ed the magnitude and spatiotemporal variability of tritium (3H) transport from the shallow unsaturated zone to the atmosphere adjacent to a low-level radioactive waste (LLRW) facility. Tritium fl uxes were calculated as the product of 3H concentrations in water vapor and respective evaporation and transpiration water-vapor fl uxes. Quarterly measured 3H concentrations in soil water vapor and in leaf water of the dominant creosote-bush [Larrea tridentata (DC.) Coville] were spatially extrapolated and temporally interpolated to develop daily maps of contamination across the 0.76-km2 study area. Maximum plant and root-zone soil concentrations (4200 and 8700 Bq L-1, respectively) were measured 25 m from the LLRW facility boundary. Continuous evaporation was estimated using a Priestley-Taylor model and transpiration was computed as the diff erence between measured eddy-covariance evapotranspiration and estimated evaporation. The mean evaporation/transpiration ratio was 3:1. Tritium released from the study area ranged from 0.12 to 12 ??g d-1 and totaled 1.5 mg (8.2 ?? 1010 Bq) over 2 yr. Tritium fl ux variability was driven spatially by proximity to 3H source areas and temporally by changes in 3H concentrations and in the partitioning between evaporation and transpiration. Evapotranspiration removed and limited penetration of precipitation beneath native vegetation and fostered upward movement and release of 3H from below the root zone. ?? Soil Science Society of America.

  10. Indoor atmospheric corrosion of electronic materials in tropical-mountain environments

    Energy Technology Data Exchange (ETDEWEB)

    Gil, H. [Corrosion and Protection Group, University of Antioquia, Street 62 No 52-59, Medellin (Colombia)], E-mail: harveth@gmail.com; Calderon, J.A. [Corrosion and Protection Group, University of Antioquia, Street 62 No 52-59, Medellin (Colombia)], E-mail: jacalder@udea.edu.co; Buitrago, C.P.; Echavarria, A.; Echeverria, F. [Corrosion and Protection Group, University of Antioquia, Street 62 No 52-59, Medellin (Colombia)

    2010-02-15

    Indoor corrosion rate during one year exposure for carbon steel, copper, nickel, and tin was determined in three different atmospheres in Colombia. In addition, pollutants deposition rates and environmental parameters were also measured during indoor-outdoor conditions. The results show higher pollutant deposition in outdoor conditions, while inside metallic boxes the pollutant deposition significantly diminishes. No difference for relative humidity values was found between inside and outside measurements. For all samples, except nickel, the corrosion rate decrease with exposure time. The nature of corrosion products was found to be related to the exposure conditions.

  11. Atmospheric Corrosion Investigation in Industrial, Marine and Rural Environments in South-East Brazil

    International Nuclear Information System (INIS)

    ASTM 283-C, AISI 304 and 316-L steel specimens (called coupons) were exposed in marine, industrial and rural area(s) for different periods ranging between 1-12 months, in four different season campaigns. The corrosion rate was determined by chemical loss measurements. Rust characterization was performed by XRD, SEM, optical, and Moessbauer spectroscopy (in transmission and backscattering geometry). Superparamagnetic maghemite and goethite were found as corrosion products. Magnetic goethite and feroxyhite decrease with time of exposure. Lepidochrosite is detected and its intensity increase with the atmospheric exposure time. The results obtained from XRD and Moessbauer are in good agreement.

  12. Indoor atmospheric corrosion of electronic materials in tropical-mountain environments

    International Nuclear Information System (INIS)

    Indoor corrosion rate during one year exposure for carbon steel, copper, nickel, and tin was determined in three different atmospheres in Colombia. In addition, pollutants deposition rates and environmental parameters were also measured during indoor-outdoor conditions. The results show higher pollutant deposition in outdoor conditions, while inside metallic boxes the pollutant deposition significantly diminishes. No difference for relative humidity values was found between inside and outside measurements. For all samples, except nickel, the corrosion rate decrease with exposure time. The nature of corrosion products was found to be related to the exposure conditions.

  13. Impact of Atmospheric Long Range Transport of Lead, Mercury and Cadmium on the Swedish Forest Environment

    International Nuclear Information System (INIS)

    Emissions of Hg, Pb, and Cd to air are transported over wide areas in Europe and deposited far away from their sources. About 80% of the atmospheric deposition of these metals in south Sweden originate from emissions in other countries. As a result of the increased anthropogenic deposition the concentrations of Hg, Pb, and Cd in the morlayer of forest soils have increased considerably, mainly during the 20th century. Although the atmospheric deposition of these elements has declined during the most recent decades, the reduction of the input of Hg and Pb is not sufficient to prevent a further accumulation. The concentrations of Hg and Pb are still increasing by ca. 0.5and ca. 0.2% annually in the surface layer of forest soils.In contrast, the Cd concentration is currently decreasing in a large part of Sweden as a result of both deposition decreases and enhanced leaching induced by soil acidification. The accumulation factors of Hg and Pb, especially in the forest topsoils of south Sweden, are already above those at which adverse effects on soil biological processes and organisms have been demonstrated in studies of gradients from local emission sources and laboratory assessment. There are also indications of such effects at the current regional concentrations of Hg and Pbin mor layers from south Sweden, judging from observations in field and laboratory studies. There is an apparent risk of Pb induced reduction in microbial activity over parts of south Sweden. This might cause increased accumulation of organic matter and a reduced availability of soil nutrients. At current concentrations of Hg in Swedish forest soils,effects similar to those of Pb are likely. Increased concentrations of these elements in organs of mammals and birds have also been measured, though decreases have been demonstrated in recent years, related to changes in atmospheric deposition rates. As a result of current and past deposition in south Sweden, concentrations of Hg in fish have increased

  14. Substitution of Organic Solvents - a Way to improve Working Environment and reduce Emissions to the Atmosphere

    DEFF Research Database (Denmark)

    Jacobsen, Thomas

    Often there is a conflict between considerations regarding the working environment, and considerations regarding the environment, locally and globally, outside the company. When processes involving use of volatile, organic solvents are closely analyzed, it may in many cases be possible to change...... organic solvents as cleaning agents has been reached. However, some barriers to this substitution process, are found outside the printing companies. In designing of machines and auxiliary equipment, the manufacturers must take into account, that cleaning with non-volatile agents should be possible. Even a...

  15. Research on atmospheric environment carrying capacity of ports%港口大气环境承载力研究

    Institute of Scientific and Technical Information of China (English)

    刘长兵

    2012-01-01

    以秦皇岛煤炭港口为例,筛选煤粉尘(TSP)作为典型大宗散货港口大气环境优先污染物,通过对港口区域现有重点煤尘污染源、烟尘污染源和工业粉尘污染源排放和治理状况以及大气污染物迁移扩散规律的研究,结合社会、经济和环境因素,以满足秦皇岛煤炭作业环境和周边地区大气环境功能区环境质量标准为约束条件,探求了港口大气污染物排放总量及环境承载力控制目标.%In this paper,taking Qinhuangdao coal port for example,TSP was selected as the priority pollutants of atmospheric environment of the typical large-sized bulk cargo port.The emission and treatment of the existing key pollution sources for coal dust smoke and dust, industrial dust and the spreading law of air pollutants in port area were studied.Under the constraint conditions of coal working environment of Qinhuangdao and the atmospheric environment functional regionalization environmental quality standard of its surrounding areas,the control targets of the total air pollutants emission and the environment carrying capacity of port were explored with the combination of the social,economic and environmental factors.These results can provide effective technical support for the general development plan of port,dust pollution treatment and environmental feasibility study of a new port.

  16. Impact of urban atmospheric environment on hospital admissions in the elderly

    Directory of Open Access Journals (Sweden)

    Edelci Nunes da Silva

    2012-08-01

    Full Text Available OBJECTIVE: To analyze the impact of intra-urban atmospheric conditions on circulatory and respiratory diseases in elder adults. METHODS: Cross-sectional study based on data from 33,212 hospital admissions in adults over 60 years in the city of São Paulo, southeastern Brazil, from 2003 to 2007. The association between atmospheric variables from Congonhas airport and bioclimatic index, Physiological Equivalent Temperature, was analyzed according to the district's socioenvironmental profile. Descriptive statistical analysis and regression models were used. RESULTS: There was an increase in hospital admissions due to circulatory diseases as average and lowest temperatures decreased. The likelihood of being admitted to the hospital increased by 12% with 1ºC decrease in the bioclimatic index and with 1ºC increase in the highest temperatures in the group with lower socioenvironmental conditions. The risk of admission due to respiratory diseases increased with inadequate air quality in districts with higher socioenvironmental conditions. CONCLUSIONS: The associations between morbidity and climate variables and the comfort index varied in different groups and diseases. Lower and higher temperatures increased the risk of hospital admission in the elderly. Districts with lower socioenvironmental conditions showed greater adverse health impacts.

  17. Water quality monitoring by thematic mapper in coastal environments. A performance analysis of local biooptical algorithms and atmospheric correction procedures

    Energy Technology Data Exchange (ETDEWEB)

    Tassan, S. (Commission of the European Communities, Ispra (Italy). Inst. for Remote Sensing Applications); d' Alcala, M.R. (Stazione Zoologica, Napoli (Italy). Biological Oceanography Lab.)

    1993-08-01

    The Thematic Mapper (TM) sensor's ability to monitor localized phenomena associated with anthropogenic pollution in coastal waters has been investigated with reference to experimental data collected on a test site in the Gulf of Naples. In situ measurements yielded the biooptical algorithms for chlorophyll and sediment retrieval as well as an optical model for the computation of the subsurface reflectance as a function of water composition, specific to the site. The algorithms' performance was assessed through a sensitivity analysis, taking into account the correlation among chlorophyll, sediment, and yellow substance contents, as well as the stratification characteristics of the water body. Sensitivity analysis techniques were similarly used to evaluate the performance in the coastal environment of three atmospheric correction models, which assume uniform aerosol load and composition, uniform aerosol composition, and varying aerosol load and composition, respectively. A comparison with sea-truth data collected for the Land-sat overpass of 22 June 1988 showed a satisfactory correspondence between measured concentrations and concentrations retrieved from the TM data using the above atmospheric correction procedures and local biooptical algorithms. Consistent with the indications of the sensitivity analysis, the best agreement was obtained by the atmospheric model assuming varying aerosol load and composition.

  18. Atmospheric versus biological sources of polycyclic aromatic hydrocarbons (PAHs) in a tropical rain forest environment

    International Nuclear Information System (INIS)

    To distinguish between pyrogenic and biological sources of PAHs in a tropical rain forest near Manaus, Brazil, we determined the concentrations of 21 PAHs in leaves, bark, twigs, and stem wood of forest trees, dead wood, mineral topsoil, litter layer, air, and Nasutitermes termite nest compartments. Naphthalene (NAPH) was the most abundant PAH with concentrations of 35 ng m-3 in air (>85% of the Σ21PAHs concentration), up to 1000 μg kg-1 in plants (>90%), 477 μg kg-1 in litter (>90%), 32 μg kg-1 in topsoil (>90%), and 160 μg kg-1 (>55%) in termite nests. In plants, the concentrations of PAHs in general decreased in the order leaves > bark > twigs > stem wood. The concentrations of most low-molecular weight PAHs in leaves and bark were near equilibrium with air, but those of NAPH were up to 50 times higher. Thus, the atmosphere seemed to be the major source of all PAHs in plants except for NAPH. Additionally, phenanthrene (PHEN) had elevated concentrations in bark and twigs of Vismia cayennensis trees (12-60 μg kg-1), which might have produced PHEN. In the mineral soil, perylene (PERY) was more abundant than in the litter layer, probably because of in situ biological production. Nasutitermes nests had the highest concentrations of most PAHs in exterior compartments (on average 8 and 15 μg kg-1 compared to -1 in interior parts) and high PERY concentrations in all compartments (12-86 μg kg-1), indicating an in situ production of PERY in the nests. Our results demonstrate that the deposition of pyrolytic PAHs from the atmosphere controls the concentrations of most PAHs. However, the occurrence of NAPH, PHEN, and PERY in plants, termite nests, and soils at elevated concentrations supports the assumption of their biological origin. - Evidence of non-pyrolytic, biogenic production of PAHs is provided

  19. Spacecraft VHF Radio Propagation Analysis in Ocean Environments Including Atmospheric Effects

    Science.gov (United States)

    Hwu, Shian; Moreno, Gerardo; Desilva, Kanishka; Jih, CIndy

    2010-01-01

    The Communication Systems Simulation Laboratory (CSSL) at the National Aeronautics and Space Administration (NASA)/Johnson Space Center (JSC) is tasked to perform spacecraft and ground network communication system simulations. The CSSL has developed simulation tools that model spacecraft communication systems and the space/ground environment in which they operate. This paper is to analyze a spacecraft's very high frequency (VHF) radio signal propagation and the impact to performance when landing in an ocean. Very little research work has been done for VHF radio systems in a maritime environment. Rigorous Radio Frequency (RF) modeling/simulation techniques were employed for various environmental effects. The simulation results illustrate the significance of the environmental effects on the VHF radio system performance.

  20. Electrical resistivity of Nb - 2,5% Zr alloy in He atmospheres with and without neutronic radiation

    International Nuclear Information System (INIS)

    By means of electrical resistivity measurements the solution of He in the Nb-2,5% Zr alloys was studied with and without neutron irradiation. The resistivity increases with the He diffusion in the alloys during isothermal annealings. These isothermal annealings permit the determination of parameters like: relaxation time, diffusion coefficients activation energy and vacancies supersaturation. A contribution to materials technology of power reactors, is done. (Author)

  1. Problems in the simulation of atmospheric boundary layer flows. [natural wind environment in atmospheric boundary layer for aerospace and aeronautical applications

    Science.gov (United States)

    Fichtl, G. H.

    1973-01-01

    The realistic simulation of flow in the atmospheric boundary layers at heights greater than two kilometers is discussed. Information concerning horizontally homogeneous and statistically stationary atmospheric boundary layer flows is presented. The problems related to the incorporation of the information into atmospheric wind simulation programs are analyzed. The information which the meteorologist must acquire in order to provide a basis for improving the simulation of atmospheric boundary flows is explained.

  2. Advanced Sample Environments for in situ Neutron Diffraction Studies of Nuclear Materials

    International Nuclear Information System (INIS)

    Summaries of this presentation are: (1) the author successfully developed and commissioned three sample environments and applied them to study scientific problems of nuclear materials; (2) sample changer - reliable, unattended operation, Reiche and Vogel, 2010; (3) creep furnace - 1000 C, 2.7 kN, texture, Reiche et al., 2012; (4) Zr-2.5Nb pressure tubes - deconvolute the contributions of heating, phase transformation, deformation at temperature in the β-field, and phase transformation during cooling; (5) our data informs currently developed mechanical models predicting texture evolution during phase transformation and high temperature deformation (MST-8, LANL); (6) high-temperature furnace - >2200 C, texture, paper in progress; (7) UC - Bowman's NaCl-type structure correct for cubic UC2, recent reactor safetly calculations by Chevalier and Fischer (2001) and independent work by Freyss (2010) incorrect, as fluorite structure is assumed; and (8) UC - order-disorder transition starting at 1800 C discovered which will improve current models, as these do not predict this transition (e.g. Basak, 2007), or confirm the prediction (Wen et al., 2012, T-1, LANL).

  3. Quality assurance of neutron activation analysis of traces of vanadium in workplace air, the environment and human tissues

    International Nuclear Information System (INIS)

    The essentiality, distribution and toxicology of vanadium are still areas of ongoing research at the present time. Analytical quality assurance procedures, such as analysis of suitable reference materials (RMs) or comparative analyses using independent analytical techniques, should be extensively applied in these studies in order to elucidate the existing discrepancies and gaps in our knowledge of vanadium levels in the biosphere, environment and especially in human tissues, where vanadium is present at extremely low levels. Results of vanadium determination by instrumental and radiochemical neutron activation analysis at concentrations ranging from less than 0.001 mg/kg to several hundreds of mg/kg in a number of environmental and biological RMs, mostly those recently prepared, are presented. Problems of quality assurance in vanadium related environmental studies are discussed in terms of the availability of suitable matrix and vanadium level matched RMs for the following matrices: workplace and ambient air; soils, sediments and waters; botanical materials; and animal and human tissues. The possibilities of pursuing quality assurance by comparative analyses of the above matrices using independent analytical techniques are briefly evaluated. The need for quality assurance of the pre-analytical stages of the above studies, especially those aimed at establishing normal vanadium values in selected human tissues, is also mentioned. (author)

  4. EntrySat: A 3U CubeStat to study the reentry atmospheric environment

    Science.gov (United States)

    Anthony, Sournac; Raphael, Garcia; David, Mimoun; Jeremie, Chaix

    2016-04-01

    ISAE France Entrysat has for main scientific objective the study of uncontrolled atmospheric re-entry. This project, is developed by ISAE in collaboration with ONERA and University of Toulouse, is funded by CNES, in the overall frame of the QB50 project. This nano-satellite is a 3U Cubesat measuring 34*10*10 cm3, similar to secondary debris produced during the break up of a spacecraft. EntrySat will collect the external and internal temperatures, pressure, heat flux, attitude variations and drag force of the satellite between ≈150 and 90 km before its destruction in the atmosphere, and transmit them during the re-entry using the IRIDIUM satellite network. The result will be compared with the computations of MUSIC/FAST, a new 6-degree of freedom code developed by ONERA to predict the trajectory of space debris. In order to fulfil the scientific objectives, the satellite will acquire 18 re-entry sensors signals, convert them and compress them, thanks to an electronic board developed by ISAE students in cooperation with EREMS. In order to transmit these data every second during the re-entry phase, the satellite will use an IRIDIUM connection. In order to keep a stable enough attitudes during this phase, a simple attitude orbit and control system using magnetotorquers and an inertial measurement unit (IMU) is developed at ISAE by students. A commercial GPS board is also integrated in the satellite into Entry Sat to determine its position and velocity which are necessary during the re-entry phase. This GPS will also be used to synchronize the on-board clock with the real-time UTC data. During the orbital phase (≈2 year) EntrySat measurements will be recorded transmitted through a more classical "UHF/VHF" connection. Preference for presentation: Poster Most suitable session: Author for correspondence: Dr Raphael F. Garcia ISAE 10, ave E. Belin, 31400 Toulouse, France Raphael.GARCIA@isae.fr +33 5 61 33 81 14

  5. A new apparatus design for high temperature (up to 950 °C) quasi-elastic neutron scattering in a controlled gaseous environment

    International Nuclear Information System (INIS)

    A design for a sample cell system suitable for high temperature Quasi-Elastic Neutron Scattering (QENS) experiments is presented. The apparatus was developed at the Spallation Neutron Source in Oak Ridge National Lab where it is currently in use. The design provides a special sample cell environment under controlled humid or dry gas flow over a wide range of temperature up to 950 °C. Using such a cell, chemical, dynamical, and physical changes can be studied in situ under various operating conditions. While the cell combined with portable automated gas environment system is especially useful for in situ studies of microscopic dynamics under operational conditions that are similar to those of solid oxide fuel cells, it can additionally be used to study a wide variety of materials, such as high temperature proton conductors. The cell can also be used in many different neutron experiments when a suitable sample holder material is selected. The sample cell system has recently been used to reveal fast dynamic processes in quasi-elastic neutron scattering experiments, which standard probes (such as electrochemical impedance spectroscopy) could not detect. In this work, we outline the design of the sample cell system and present results demonstrating its abilities in high temperature QENS experiments

  6. A new apparatus design for high temperature (up to 950 °C) quasi-elastic neutron scattering in a controlled gaseous environment

    Energy Technology Data Exchange (ETDEWEB)

    Al-Wahish, Amal [Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Armitage, D.; Hill, B.; Mills, R.; Santodonato, L.; Herwig, K. W. [Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37861-6475 (United States); Al-Binni, U. [Department of Physics, Astronomy and Geology, Berry College, Mount Berry, Georgia 30149 (United States); Jalarvo, N. [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS), Outstation at Spallation Neutron Source (SNS), and Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473 (United States); Mandrus, D. [Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6100 (United States)

    2015-09-15

    A design for a sample cell system suitable for high temperature Quasi-Elastic Neutron Scattering (QENS) experiments is presented. The apparatus was developed at the Spallation Neutron Source in Oak Ridge National Lab where it is currently in use. The design provides a special sample cell environment under controlled humid or dry gas flow over a wide range of temperature up to 950 °C. Using such a cell, chemical, dynamical, and physical changes can be studied in situ under various operating conditions. While the cell combined with portable automated gas environment system is especially useful for in situ studies of microscopic dynamics under operational conditions that are similar to those of solid oxide fuel cells, it can additionally be used to study a wide variety of materials, such as high temperature proton conductors. The cell can also be used in many different neutron experiments when a suitable sample holder material is selected. The sample cell system has recently been used to reveal fast dynamic processes in quasi-elastic neutron scattering experiments, which standard probes (such as electrochemical impedance spectroscopy) could not detect. In this work, we outline the design of the sample cell system and present results demonstrating its abilities in high temperature QENS experiments.

  7. Atmospheric deposition of heavy metals in Norway studied by the analysis of moss samples using neutron activation analysis and atomic absorption spectrometry

    International Nuclear Information System (INIS)

    In a study of the atmospheric deposition of trace elements in different parts of Norway, samples of the moss Hylocomium Splendens were analyzed with respect to 28 elements. The determination of Cu, Zn, Cd and Pb was carried out by atomic absorption spectrophotometry, while 24 additional elements were determined by instrumental neutron activation analysis. In samples from southemmost Norway, a substantially higher concentration was found for elements such as Pb, Sb, V, Cr, Cu, Zn, As, Se, Mo, Ag and Cd than in samples from places located in the more northerly parts of the country. The results indicate that sources which are to the south and south-west of Scandinavia, contribute significantly to heavy metal deposition in Norway. (author)

  8. The polluted atmosphere of the white dwarf NLTT 25792 and the diversity of circumstellar environments

    CERN Document Server

    Vennes, S

    2013-01-01

    We present an analysis of X-Shooter spectra of the polluted, hydrogen-rich white dwarf NLTT 25792. The spectra show strong lines of calcium (Ca H&K, near-infrared calcium triplet, and Ca I 4226 and numerous lines of iron along with magnesium and aluminum lines from which we draw the abundance pattern. Moreover, the photospheric Ca H&K lines are possibly blended with a circumstellar component shifted by -20 km/s relative to the photosphere. A comparison with a sample of four white dwarfs with similar parameters show considerable variations in their abundance patterns, particularly in the calcium to magnesium abundance ratio that varies by a factor of five within this sample. The observed variations, even after accounting for diffusion effects, imply similar variations in the putative accretion source. Also, we find that silicon and sodium are significantly underabundant in the atmosphere of NLTT 25792, a fact that may offer some clues on the nature of the accretion source.

  9. Effect of Ground Surface Roughness on Atmospheric Dispersion and Dry Deposition of Cs-137 in the UAE Environment

    International Nuclear Information System (INIS)

    The site of nuclear power plant (NPP) in the UAE has several unique characteristics as a NPP on the desert environment near coastal region. Those characteristics are represented like below: · Arid ground surface · Low ground surface roughness length · Relatively simple (flat) terrain · Extremely low precipitation · Intense solar radiation and high temperature in day time · Sea breeze · Relatively high humidity of atmosphere · Etc. From the review of this desert environment in the UAE, low ground surface roughness is regarded as one of definitively different characteristics from that of other NPP sites. In this context, surface roughness is selected as independent variables for the sensitivity analyses in this research. Another important reason of this selection is that this parameters is less dependent on the day and night change than other parameters. With ground level concentration, dry deposition rate has been chosen as a dependent variable to be considered rather than wet deposition because UAE shows almost zero rainfall especially in summer. Lower ground level concentration of Cs-137 near the site and extremely lower dry deposition of Cs-137 are predicted in the UAE environment because of the lower ground surface roughness of the desert

  10. Effect of Ground Surface Roughness on Atmospheric Dispersion and Dry Deposition of Cs-137 in the UAE Environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sungyeop; Beeley, Philip A. [Khalifa Univ. of Science, Abu Dhabi (United Arab Emirates); Kim, Sungyeop; Chang, Soonheung; Lee, Kunjai [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2013-05-15

    The site of nuclear power plant (NPP) in the UAE has several unique characteristics as a NPP on the desert environment near coastal region. Those characteristics are represented like below: · Arid ground surface · Low ground surface roughness length · Relatively simple (flat) terrain · Extremely low precipitation · Intense solar radiation and high temperature in day time · Sea breeze · Relatively high humidity of atmosphere · Etc. From the review of this desert environment in the UAE, low ground surface roughness is regarded as one of definitively different characteristics from that of other NPP sites. In this context, surface roughness is selected as independent variables for the sensitivity analyses in this research. Another important reason of this selection is that this parameters is less dependent on the day and night change than other parameters. With ground level concentration, dry deposition rate has been chosen as a dependent variable to be considered rather than wet deposition because UAE shows almost zero rainfall especially in summer. Lower ground level concentration of Cs-137 near the site and extremely lower dry deposition of Cs-137 are predicted in the UAE environment because of the lower ground surface roughness of the desert.

  11. Water use strategies and ecosystem-atmosphere exchange of CO2 in two highly seasonal environments

    Directory of Open Access Journals (Sweden)

    A. Arneth

    2006-01-01

    Full Text Available We compare assimilation and respiration rates, and water use strategies in four divergent ecosystems located in cold-continental central Siberia and in semi-arid southern Africa. These seemingly unrelated systems have in common a harsh and highly seasonal environment with a very sharp transition between the dormant and the active season, with vegetation facing dry air and soil conditions for at least part of the year. Moreover, the northern high latitudes and the semi-arid tropics will likely experience changes in key environmental parameters (e.g., air temperature and precipitation in the future; indeed, in some regions marked climate trends have already been observed over the last decade or so. The magnitude of instantaneous or daily assimilation and respiration rates, derived from one to two years of eddy covariance measurements in each of the four ecosystems, was not related to the growth environment. For instance, respiration rates were clearly highest in the two deciduous systems included in the analysis (a Mopane woodland in northern Botswana and a Downy birch forest in Siberia; >300 mmol m−2 d−1, while assimilation rates in the Mopane woodland were relatively similar to a Siberian Scots pine canopy for a large part of the active season (ca. 420 mmol m−2 d−1. Acknowledging the limited number of ecosystems compared here, these data nevertheless demonstrate that factors like vegetation type, canopy phenology or ecosystem age can override larger-scale climate differences in terms of their effects on carbon assimilation and respiration rates. By far the highest rates of assimilation were observed in Downy birch, an early successional species. These were achieved at a rather conservative water use, as indicated by relatively low levels of λ, the marginal water cost of plant carbon gain. Surprisingly, the Mopane woodland growing in the semi-arid environment had significantly higher values of λ. However, its water use strategy included

  12. Water use strategies and ecosystem-atmosphere exchange of CO2 in two highly seasonal environments

    Directory of Open Access Journals (Sweden)

    O. Kolle

    2006-04-01

    Full Text Available We compare assimilation and respiration rates, and water use strategies in four divergent ecosystems located in cold-continental central Siberia and in semi-arid southern Africa. These seemingly unrelated systems have in common a harsh and highly seasonal environment with a very sharp transition between the dormant and the active season, and with vegetation facing dry air and soil conditions for at least part of the year. Moreover, the northern high latitudes and the semi-arid tropics will likely experience changes in key environmental parameters (e.g., air temperature and precipitation in the future; indeed, in some regions marked climate trends have already been observed over the last decade or so. The magnitude of instantaneous or daily assimilation and respiration rates, derived from one to two years of eddy covariance measurements in each of the four ecosystems, was not related to the growth environment. For instance, respiration rates were clearly highest in the two deciduous systems included in the analysis (a Mopane woodland in northern Botswana and a Downy birch forest in Siberia; >300 mmol m−2 d−1, while assimilation rates in the Mopane woodland were relatively similar to a Siberian Scots pine canopy for a large part of the active season (ca. 420 mmol m−2 d−1. Acknowledging the limited number of ecosystems compared here, these data nevertheless suggest that factors like vegetation type, canopy phenology or ecosystem age can override larger-scale climate differences in terms of their effects on carbon assimilation and respiration rates. By far the highest rates of assimilation were observed in Downy birch, an early successional species. These were achieved at a rather conservative water use, as indicated by relatively low levels of λ, the marginal water cost of plant carbon gain. Surprisingly, the Mopane woodland growing in the semi-arid environment had significantly higher values of λ. However, its water use strategy

  13. Horizontal Advection and Mixing of Pollutants in the Urban Atmospheric Environment

    Science.gov (United States)

    Magnusson, S. P.; Entekhabi, D.; Britter, R.; Norford, L.; Fernando, H. J.

    2013-12-01

    Although urban air quality and its impacts on the public health have long been studied, the increasing urbanization is raising concerns on how to better control and mitigate these health impacts. A necessary element in predicting exposure levels is fundamental understanding of flow and dispersion in urban canyons. The complex topology of building structures and roads requires the resolution of turbulence phenomena within urban canyons. The use of dense and low porosity construction material can lead to rapid heating in response to direct solar exposure due to large thermal mass. Hence thermal and buoyancy effects may be as important as mechanically-forced or shear-induced flows. In this study, the transport of pollutants within the urban environment, as well as the thermal and advection effects, are investigated. The focus is on the horizontal transport or the advection effects within the urban environment. With increased urbanization and larger and more spread cities, concern about how the upstream air quality situation can affect downstream areas. The study also examines the release and the dispersion of hazardous material. Due to the variety and complexity of urban areas around the world, the urban environment is simplified into adjacent two-dimensional urban street canyons. Pollutants are released inside each canyon. Computational Fluid Dynamics (CFD) simulations are applied to evaluate and quantify the flow rate out of each canyon and also the exchange of pollutants between the canyons. Imagine a row of ten adjacent urban street canyons of aspect ratio 1 with horizontal flow perpendicular to it as shown in the attached figure. C is the concentration of pollutants. The first digit indicates in what canyon the pollutant is released and the second digit indicates the location of that pollutant. For example, C3,4 is the concentration of pollutant released inside canyon 3 measured in canyon 4. The same amount of pollution is released inside the ten street canyons

  14. Demonstrating the Operational Value of Atmospheric Infrared Sounder (AIRS) Retrieved Profiles in the Pre-Convective Environment

    Science.gov (United States)

    Kozlowski, Danielle M.; Zavodsky, T.; Jedloved, Gary J.

    2011-01-01

    The Short-term Prediction Research and Transition Center (SPoRT) is a collaborative partnership between NASA and operational forecasting partners, including a number of National Weather Service offices. SPoRT provides real-time NASA products and capabilities to its partners to address specific operational forecast challenges. One operational forecast challenge is forecasting convective weather in data-void regions such as large bodies of water (e.g. Gulf of Mexico). To address this forecast challenge, SPoRT produces a twice-daily three-dimensional analysis that blends a model first-guess from the Advanced Research Weather Research and Forecasting (WRF-ARW) model with retrieved profiles from the Atmospheric Infrared Sounder (AIRS) -- a hyperspectral sounding instrument aboard NASA's Aqua satellite that provides temperature and moisture profiles of the atmosphere. AIRS profiles are unique in that they give a three dimensional view of the atmosphere that is not available through the current rawinsonde network. AIRS has two overpass swaths across North America each day, one valid in the 0700-0900 UTC timeframe and the other in the 1900-2100 UTC timeframe. This is helpful because the rawinsonde network only has data from 0000 UTC and 1200 UTC at specific land-based locations. Comparing the AIRS analysis product with control analyses that include no AIRS data demonstrates the value of the retrieved profiles to situational awareness for the pre-convective (and convective) environment. In an attempt to verify that the AIRS analysis was a good representation of the vertical structure of the atmosphere, both the AIRS and control analyses are compared to a Rapid Update Cycle (RUC) analysis used by operational forecasters. Using guidance from operational forecasters, convective available potential energy (CAPE) was determined to be a vital variable in making convective forecasts and is used herein to demonstrate the utility of the AIRS profiles in changing the vertical

  15. Contingency Trajectory Design for a Lunar Orbit Insertion Maneuver Failure by the Lunar Atmosphere Dust Environment Explorer (LADEE) Spacecraft

    Science.gov (United States)

    Genova, Anthony L.; Loucks, Michael; Carrico, John

    2014-01-01

    The purpose of this extended abstract is to present results from a failed lunar-orbit insertion (LOI) maneuver contingency analysis for the Lunar Atmosphere Dust Environment Explorer (LADEE) mission, managed and operated by NASA Ames Research Center in Moffett Field, CA. The LADEE spacecrafts nominal trajectory implemented multiple sub-lunar phasing orbits centered at Earth before eventually reaching the Moon (Fig. 1) where a critical LOI maneuver was to be performed [1,2,3]. If this LOI was missed, the LADEE spacecraft would be on an Earth-escape trajectory, bound for heliocentric space. Although a partial mission recovery is possible from a heliocentric orbit (to be discussed in the full paper), it was found that an escape-prevention maneuver could be performed several days after a hypothetical LOI-miss, allowing a return to the desired science orbit around the Moon without leaving the Earths sphere-of-influence (SOI).

  16. Exposures to the atmospheric ionizing radiation environment: a comparison between Icelandic and Italian civilian aviation flight personnel

    International Nuclear Information System (INIS)

    A comparative study has been performed between the radiation exposure patterns of the Icelandic and the Italian civilian aviation flight personnel. These two populations represent two extremes within the group of worldwide airline personnel. The Icelandic crew members, like only in the world their Canadian colleagues, always fly over or very close to the geomagnetic pole, and are this way exposed to high doses within each flight leg, whereas the Italian crew members, apart from transatlantic flights, are always flying close to the geomagnetic equator or anyhow quite far from the geomagnetic pole, receiving a small dose rates for each flight. For both Icelandic and Italian flights the actual radiation dose calculations along the various flight legs have been performed taking into account the different flight profiles for different routes and the variations over the considered time period of the heliocentric potential and of the geomagnetic field, in order to take into account the whole atmospheric neutron spectrum. Average dose rate values for aircraft types and routes have been obtained, along with their variations with time, and the different exposure patterns have been put into evidence. The annual individual dose for each crewmember is obtained by multiplying the average dose rates by the number of block hours for aircraft type flown each year. In the future it will be possible to analyze dose rates and cumulative doses to crew members in relation with different health outcomes for the two considered air crew groups. The data analysis in this respect is in progress, and the first exposure results are expected soon

  17. Environment

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2016-01-01

    The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the...... origin and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....

  18. Variable Temperature Setup for Scanning Electron Microscopy in Liquids and Atmospheric Pressure Gaseous Environments

    Science.gov (United States)

    Al-Asadi, Ahmed; Zhang, Jie; Li, Jianbo; Denault, Lauraine; Potyrailo, Radislav; Kolmakov, Andrei

    2014-03-01

    A thermoelectric cooling / heating setup for commercial Quantomix QX WETSEM scanning electron microscopy environmental cells was designed and tested. This addition allows extending ambient pressure in situ studies to be conducted in a wide temperature range both in liquid and gaseous environments. Instead of cooling/heating the entire body of QX-WETCELL, ultrathin polyimide electron transparent membrane window supported by metal mesh on the top of the cell has been used as an agent for heat transfer to/ from the Pelltier element. A butterfly wing of Morph sulkowskyi has been used as a model object in the QX-WETCELL's chamber due to its unique micro/nanostructure and peculiar wettability behavior. The dynamics of the water desorption, condensation and freezing processes were observed complementary using both optical microscopy and Scanning Electron Microscopy in vivo. The observations revel that the initial droplet formation were most likely taking place on the top of the wing ridges due to the waxy component of its surface. In addition, The SEM observation showed that the high intensity electron beam can heat the butterfly wing locally delaying the water condensation and freezing processes.

  19. Low-background neutron activation analysis. A powerful tool for atmospheric mineral dust analysis in ice cores

    International Nuclear Information System (INIS)

    The application of instrumental neutron activation analysis (INAA) for multi-elemental analysis of samples of extremely reduced mass such as dust samples extracted from ice cores requires specific efforts towards the development of a 'low level counting' analytical technique. An analytical protocol specifically designed for this kind of samples, based on low-background INAA (LBNAA) is here presented. A first application of the method was successfully performed on samples from the new alpine firn core NextData-LYS12. Sub-ng detection limits were reached for many elements. According to this point the technique is also potentially suitable to be applied to polar ice core samples. (author)

  20. Neutron activation analysis of atmospheric biomonitors from the Azores. A comparative study of lower and higher plants

    International Nuclear Information System (INIS)

    Within an extensive survey of lower and higher plants in the Azores' Terceira and Santa Maria islands, this study is focused on the evaluation of ectohydric bryophytes and bark from Cryptomeria japonica as an alternative to epiphytic lichens for air-monitoring purposes. Neutron activation analysis (k0-NAA) has been applied to all field samples for elemental determinations. Judging from the present results, and since the islands embody most features of the whole archipelago, bryophytes do not appear as an option for further campaigns in the Azores, due to scanty supply and relatively poor performance as biomonitors. On the other hand, comparisons of bark with lichens collected at the same sites seem fairly good, and elements are enriched in bark to an even greater extent than in lichens. All things considered - including material availability and ecological concern - bark stands for a sensible choice for biomonitoring in the Azores. (author)

  1. Cosmic-ray-induced ship-effect neutron measurements and implications for cargo scanning at borders

    International Nuclear Information System (INIS)

    Neutron measurements are used as part of the interdiction process for illicit nuclear materials at border crossings. Even though the natural neutron background is small, its variation can impact the sensitivity of detection systems. The natural background of neutrons that is observed in monitoring instruments arises almost entirely from cosmic-ray-induced cascades in the atmosphere and the surrounding environment. One significant source of variation in the observed neutron background is produced by the 'ship effect' in large quantities of cargo that transit past detection instruments. This paper reports on results from measurements with typical monitoring equipment of ship effect neutrons in various materials. One new result is the 'neutron shadow shielding' effect seen with some low neutron density materials

  2. Aircraft observations of surface-atmosphere exchange during and after snow melt for different arctic environments: MAGS 1999

    Science.gov (United States)

    Brown-Mitic, Constance M.; MacPherson, Ian J.; Schuepp, Peter H.; Nagarajan, Badrinath; Yau, Peter M. K.; Bales, Roger

    2001-12-01

    The arctic environment, and in particular the Mackenzie Basin, displays a very dynamic interrelationship between the atmosphere and the surface for the different ecosystems represented. The Canadian Twin Otter research aircraft flew a total of 24 grid and long regional transects, over tundra, forest and delta ecosystems, during the period of snow melt (late May-early June) and early summer (early July) as part of the 1999 Mackenzie Area GEWEX (Global Energy and Water Cycle Experiment) Study (MAGS) field campaign. Observations over tundra showed a sharp rise in the sensible heat flux at the onset of melt, reaching a maximum at the end of the melting period similar to those observed in early summer. The latent heat flux showed a more gradual rise from snowmelt to early summer with a Bowen ratio (sensible heat/latent heat) of two during melt. The forested system demonstrated a similar gradual rise in the latent heat flux, whereas the sensible heat flux was already high with Bowen ratios reaching three at the start of the observation period in late May. The gradual rise in latent heat flux can be tied to gradual thawing of the root zone and the onset of photosynthesis activity. The relatively low solar elevation angle and earlier start of snow melt along the regional transect may account for the much larger sensible heat flux. An analysis of the turbulent coherent structures indicates that the spatial density of structures for both latent heat and sensible heat increases strongly with season, from snow melt into the early summer conditions. This has implications for sampling criteria and optimum flux averaging period.There are distinct differences in energy partitioning between the various arctic ecosystems. At the beginning of the observation period, almost all the net radiation over the delta and tundra regions is utilized in non-turbulent form, whereas the forested areas use less than 50%. Model simulations of the ground heat flux showed observed diurnal imbalances

  3. Elevated atmospheric [CO2 ] can dramatically increase wheat yields in semi-arid environments and buffer against heat waves.

    Science.gov (United States)

    Fitzgerald, Glenn J; Tausz, Michael; O'Leary, Garry; Mollah, Mahabubur R; Tausz-Posch, Sabine; Seneweera, Saman; Mock, Ivan; Löw, Markus; Partington, Debra L; McNeil, David; Norton, Robert M

    2016-06-01

    Wheat production will be impacted by increasing concentration of atmospheric CO2 [CO2 ], which is expected to rise from about 400 μmol mol(-1) in 2015 to 550 μmol mol(-1) by 2050. Changes to plant physiology and crop responses from elevated [CO2 ] (e[CO2 ]) are well documented for some environments, but field-level responses in dryland Mediterranean environments with terminal drought and heat waves are scarce. The Australian Grains Free Air CO2 Enrichment facility was established to compare wheat (Triticum aestivum) growth and yield under ambient (~370 μmol(-1) in 2007) and e[CO2 ] (550 μmol(-1) ) in semi-arid environments. Experiments were undertaken at two dryland sites (Horsham and Walpeup) across three years with two cultivars, two sowing times and two irrigation treatments. Mean yield stimulation due to e[CO2 ] was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%, depending on environment. Under supplemental irrigation, e[CO2 ] stimulated yields at Horsham by 37% compared to 13% under rainfed conditions, showing that water limited growth and yield response to e[CO2 ]. Heat wave effects were ameliorated under e[CO2 ] as shown by reductions of 31% and 54% in screenings and 10% and 12% larger kernels (Horsham and Walpeup). Greatest yield stimulations occurred in the e[CO2 ] late sowing and heat stressed treatments, when supplied with more water. There were no clear differences in cultivar response due to e[CO2 ]. Multiple regression showed that yield response to e[CO2 ] depended on temperatures and water availability before and after anthesis. Thus, timing of temperature and water and the crop's ability to translocate carbohydrates to the grain postanthesis were all important in determining the e[CO2 ] response. The large responses to e[CO2 ] under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing

  4. Neutron Reference Benchmark Field Specifications: ACRR Polyethylene-Lead-Graphite (PLG) Bucket Environment (ACRR-PLG-CC-32-CL).

    Energy Technology Data Exchange (ETDEWEB)

    Vega, Richard Manuel [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parm, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Griffin, Patrick J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Vehar, David W. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-07-01

    This report was put together to support the International Atomic Energy Agency (IAEA) REAL- 2016 activity to validate the dosimetry community’s ability to use a consistent set of activation data and to derive consistent spectral characterizations. The report captures details of integral measurements taken in the Annular Core Research Reactor (ACRR) central cavity with the Polyethylene-Lead-Graphite (PLG) bucket, reference neutron benchmark field. The field is described and an “a priori” calculated neutron spectrum is reported, based on MCNP6 calculations, and a subject matter expert (SME) based covariance matrix is given for this “a priori” spectrum. The results of 37 integral dosimetry measurements in the neutron field are reported.

  5. Results of measurements of an environment neutron background at BNO INR RAS objects with the helium proportional counter

    CERN Document Server

    Barabanov, I R; Gavrilyuk, Yu M; Gangapshev, A M; Gezhaev, A M; Kazalov, V V; Khokonov, A Kh; Kuzminov, V V; Panasenko, S I; Ratkevich, S S

    2015-01-01

    A method of measurements of the environmental neutron background at the Baksan Neutrino Observatory of the INR RAS are described. Measurements were done by using of a proportional counter filled with mixture of Ar(2 at)+$^3$He(4 at). The results obtained at the surface and the underground laboratory of the BNO INR RAS are presented. It is shown that a neutron background in the underground laboratory at the 4900 m w.e. depth is decreased by $\\sim 260$ times without any special shield in a comparison with the Earth surface. A neutron flux density in the 5-1323.5~cm air height region is constant within the determination error and equal to $(7.1\\pm0.1_{\\rm{stat}}\\pm0.3_{\\rm{syst}})\\times10^{-3}$ s$^{-1}\\cdot$cm$^{-2}$.

  6. A self-biased neutron detector based on an SiC semiconductor for a harsh environment.

    Science.gov (United States)

    Ha, Jang Ho; Kang, Sang Mook; Park, Se Hwan; Kim, Han Soo; Lee, Nam Ho; Song, Tae-Yung

    2009-01-01

    Neutron detector based on radiation-hard semiconductor materials like SiC, diamond and AlN has recently emerged as an attractive device for an in-core reactor neutron flux monitoring, a spent fuel characterization, and a home land security application. For the purpose of field measurement activity, a radiation detector having a low-power consumption, a mechanical stability and a radiation hardness is required. Our research was focused on the development of a radiation-resistive neutron semiconductor detector based on a wide band-gap SiC semiconductor. And also it will be operated at a zero-biased voltage using a strong internal electric field. The charge collection efficiency (CCE) was over 80% when the biased voltage was zero. When the biased voltage was applied above 20V, the charge collection efficiency reached 100%. PMID:19362006

  7. Charge-injection-device performance in the high-energy-neutron environment of laser-fusion experiments

    International Nuclear Information System (INIS)

    Charge-injection devices (CIDs) are being used to image x rays in laser-fusion experiments on the University of Rochester's OMEGA Laser System. The CID cameras are routinely used up to the maximum neutron yields generated (∼1014 DT). The detectors are deployed in x-ray pinhole cameras and Kirkpatrick-Baez microscopes. The neutron fluences ranged from ∼107 to ∼109 neutrons/cm2 and useful x-ray images were obtained even at the highest fluences. It is intended to use CID cameras at the National Ignition Facility (NIF) as a supporting means of recording x-ray images. The results of this work predict that x-ray images should be obtainable on the NIF at yields up to ∼1015, depending on distance and shielding.

  8. Forward to all-around survey of environmental neutrons from cosmic ray secondary neutron measurements. History and prospects

    International Nuclear Information System (INIS)

    At the present stage of our civilization, environmental neutrons come from not only cosmic ray but also the various kinds of nuclear facilities where uranium, plutonium, californium-252, and other transuranium elements are treated in a large scale. To be regret, those neutron-emitting elements have already been released into the environment by experiments with the military purpose, and been distributed among atmosphere, hydrosphere and geosphere in further larger scale than the peaceful use of nuclear energy. Now environmental neutrons should be surveyed against the horizontal component from the nuclear facilities, upward component from soil, and downward component as secondary neutron from cosmic ray, which is to be regarded as background neutron in the environment. The third category of neutrons have long been surveyed by Y. Nishina and his group of the Institute of Physical and Chemical Research (IPCR) since 1970 at the Itabashi Branch (Itabashi, Tokyo) of IPCR. The BF3 gas-filled monitors (20 cm in diameter x 200 cm) of 28 (36 at maximum) vessels were used for neutrons till Sept. of 1998, and were transferred to Yanpahchin, Tibet, China for the primary neutrons that might be preferred to secondary ones by researchers of the cosmic ray. A critical accident happened at the Tokai facilities of JCO (Japan Conversion Organization) on Sept. 30 1999, and was discussed in various contexts at home and in a severe tone abroad. A background survey of the environmental neutrons has not been made at any nuclear site or facilities concerning fission in this country. The neutron monitor which detected and recorded the neutrons from the JCO critical accidents was what had been equipped for the fusion research, but not for fission application. Radiation education on neutron has not been made in both school and social education. Basic scientists also may be responsible for the critical accident through making light of these fundamental aspects of nuclear technology. In this

  9. Effect of different lay-ups on the microstructure, mechanical properties and neutron transmission of neutron shielding fibre metal laminates

    Science.gov (United States)

    Fu, Xuelong; Tang, Xiaobin; Hu, Yubing; Li, Huaguan; Tao, Jie

    2016-07-01

    A novel neutron shielding fibre metal laminates (NSFMLs) with different lay-ups, composed of stacking layers of AA6061 plates, neutron shielding composite and carbon fibre reinforced polyimide (CFRP), were fabricated using hot molding process in atmospheric environments. The microstructure, mechanical properties and neutron transmission of the NSFMLs were evaluated, respectively. The results indicated that the NSFMLs possessed good mechanical properties owing to the good interfacial adhesion of the components. Tensile strength and elastic modulus of the NSFMLs increased with the numbers of lay-ups, while the elongation to fracture exhibited obvious declining tendency. Flexural strength and modulus of the NSFMLs were improved obviously with the increasing of stacking layers. Neutron transmission of the NSFMLs decreased obviously with increasing the number of lay-ups, owing to the increase of 10B areal density. Besides, the effect of carbon fibres on the neutron shielding performance of the NSFMLs was also taken into consideration.

  10. Natural Atmospheric Environment Model Development for the National Aeronautics and Space Administration's Second Generation Reusable Launch Vehicle

    Science.gov (United States)

    Roberts, Barry C.; Leahy, Frank; Overbey, Glenn; Batts, Glen W.; Parker, Nelson (Technical Monitor)

    2002-01-01

    The National Aeronautics and Space Administration (NASA) recently began development of a new reusable launch vehicle. The program office is located at Marshall Space Flight Center (MSFC) and is called the Second Generation Reusable Launch Vehicle (2GRLV). The purpose of the program is to improve upon the safety and reliability of the first generation reusable launch vehicle, the Space Shuttle. Specifically, the goals are to reduce the risk of crew loss to less than 1-in-10,000 missions and decreased costs by a factor of 10 to approximately $1,000 per pound of payload launched to low Earth orbit. The program is currently in the very early stages of development and many two-stage vehicle concepts will be evaluated. Risk reduction activities are also taking place. These activities include developing new technologies and advancing current technologies to be used by the vehicle. The Environments Group at MSFC is tasked by the 2GRLV Program to develop and maintain an extensive series of analytical tools and environmental databases which enable it to provide detailed atmospheric studies in support of structural, guidance, navigation and control, and operation of the 2GRLV.

  11. CROSS DRIVE: A Collaborative and Distributed Virtual Environment for Exploitation of Atmospherical and Geological Datasets of Mars

    Science.gov (United States)

    Cencetti, Michele

    2016-07-01

    European space exploration missions have produced huge data sets of potentially immense value for research as well as for planning and operating future missions. For instance, Mars Exploration programs comprise a series of missions with launches ranging from the past to beyond present, which are anticipated to produce exceptional volumes of data which provide prospects for research breakthroughs and advancing further activities in space. These collected data include a variety of information, such as imagery, topography, atmospheric, geochemical datasets and more, which has resulted in and still demands, databases, versatile visualisation tools and data reduction methods. Such rate of valuable data acquisition requires the scientists, researchers and computer scientists to coordinate their storage, processing and relevant tools to enable efficient data analysis. However, the current position is that expert teams from various disciplines, the databases and tools are fragmented, leaving little scope for unlocking its value through collaborative activities. The benefits of collaborative virtual environments have been implemented in various industrial fields allowing real-time multi-user collaborative work among people from different disciplines. Exploiting the benefits of advanced immersive virtual environments (IVE) has been recognized as an important interaction paradigm to facilitate future space exploration. The current work is mainly aimed towards the presentation of the preliminary results coming from the CROSS DRIVE project. This research received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 607177 and is mainly aimed towards the implementation of a distributed virtual workspace for collaborative scientific discovery, mission planning and operations. The purpose of the CROSS DRIVE project is to lay foundations of collaborative European workspaces for space science. It will demonstrate the feasibility and

  12. A new method based on low background instrumental neutron activation analysis for major, trace and ultra-trace element determination in atmospheric mineral dust from polar ice cores.

    Science.gov (United States)

    Baccolo, Giovanni; Clemenza, Massimiliano; Delmonte, Barbara; Maffezzoli, Niccolò; Nastasi, Massimiliano; Previtali, Ezio; Prata, Michele; Salvini, Andrea; Maggi, Valter

    2016-05-30

    Dust found in polar ice core samples present extremely low concentrations, in addition the availability of such samples is usually strictly limited. For these reasons the chemical and physical analysis of polar ice cores is an analytical challenge. In this work a new method based on low background instrumental neutron activation analysis (LB-INAA) for the multi-elemental characterization of the insoluble fraction of dust from polar ice cores is presented. Thanks to an accurate selection of the most proper materials and procedures it was possible to reach unprecedented analytical performances, suitable for ice core analyses. The method was applied to Antarctic ice core samples. Five samples of atmospheric dust (μg size) from ice sections of the Antarctic Talos Dome ice core were prepared and analyzed. A set of 37 elements was quantified, spanning from all the major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) to trace ones, including 10 (La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu) of the 14 natural occurring lanthanides. The detection limits are in the range of 10(-13)-10(-6) g, improving previous results of 1-3 orders of magnitude depending on the element; uncertainties lies between 4% and 60%. PMID:27154827

  13. Assessment of atmospheric deposition of heavy metals and other elements in Belgrade using the moss biomonitoring technique and neutron activation analysis

    International Nuclear Information System (INIS)

    The study aimed at assessing atmospheric deposition of heavy metals and other elements using the moss genera Brachythecium sp. (B. rutabulum and B. salebrosum) and Eurhynchium sp. (E. hians and E. striatum) collected in autumn 2004 in the urban area of Belgrade. The concentrations of 36 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Dy, Hf, Ta, W, Hg, Th, U) were determined in moss and local topsoil samples by instrumental neutron activation analysis. The concentration of elements in moss positively correlated to those obtained for topsoil. High enrichment factors for As, Zn, Mo, Br, Sb, Se, Hg, and Cl, calculated to continental crust composition, gave an evidence for anthropogenic impact on urban area, mainly due to intensive vehicular traffic and fossil fuel combustion. The concentrations of elements in moss, characteristic for fossil fuel combustion, obtained in this study, were substantially lower than in the previous investigation (2000) conducted in the area of Belgrade. The level of concentrations for V, Cr, Ni, and As in moss from this study correlated to those measured for neighboring countries, and were several times higher than the base-level data from low polluted areas. The level of accumulated elements in both investigated moss genera were similar and all studied species could be combined for biomonitoring purposes in urban areas

  14. Neutron Scattering

    International Nuclear Information System (INIS)

    The neutron probe is a standard tool for measuring soil water content. This article provides an overview of the underlying theory, describes the methodology for its calibration and use, discusses example applications, and identifies the safety issues. Soil water makes land-based life possible by satisfying plant water requirements, serving as a medium for nutrient movement to plant roots and nutrient cycling, and controlling the fate and transport of contaminants in the soil environment. Therefore, a successful understanding of the dynamics of plant growth, nutrient cycling, and contaminant behavior in the soil requires knowledge of the soil water content as well as its spatial and temporal variability. After more than 50 years, neutron probes remain the most reliable tool available for field monitoring of soil water content. Neutron probes provide integrated measurements over relatively large volumes of soil and, with proper access, allow for repeated sampling of the subsurface at the same locations. The limitations of neutron probes include costly and time-consuming manual operation, lack of data automation, and costly regulatory requirements. As more non-radioactive systems for soil water monitoring are developed to provide automated profiling capabilities, neutron-probe usage will likely decrease. Until then, neutron probes will continue to be a standard for reliable measurements of field water contents in soils around the globe

  15. Stress Corrosion of Carbon Steel in Three Different Atmospheric Environments%碳钢在三种大气环境中的应力腐蚀

    Institute of Scientific and Technical Information of China (English)

    曹公望; 王振尧; 刘雨薇; 汪川

    2015-01-01

    ABSTRACT:Objective To research the stress corrosion failure of No.45 and Q235 carbon steels in different kinds of atmospheric environments. Methods No.45 and Q235 carbon steels were used to prepare U-shape samples and tensile samples. The corrosion test in atmospheric exposure for three years was conducted in atmospheric environment in Wanning, Jiangjin and Xishuangbanna. The rust layer depth analysis and the tensile failure analysis were performed to investigate the stress corrosion of carbon steel in different atmospheric environments. Results The u-shaped sample under the influence of the tensile stress in the three kinds of atmospheric environment had different depth of corrosion pits. Strength of extension had declined in a short period of time and failured in Wanning atmospheric environment, while it declined slowly in xishuangbanna and Jiangjin atmospheric environment. Conclusion Due to difference inatmospheric contaminants, the corrosion degree varied for U-shape samples under the influence of tensile stress. The tensile strength of tensile samples was periodically decreased during the process of corrosion.%目的:研究45#碳钢和Q235碳钢在不同大气环境中的应力腐蚀失效。方法将45#碳钢和Q235碳钢制备成U型样和拉伸试样,分别在万宁、江津和西双版纳三种大气环境下进行为期3年的暴露试验,利用截面锈层深度分析和拉伸断裂分析两种手段,分析两种碳钢在不同大气环境下的应力腐蚀行为。结果拉应力影响下的U型样在三种大气环境中出现了不同深度的腐蚀坑。拉伸试样在万宁大气环境下短时间内抗拉强度急剧下降并失效,在西双版纳和江津大气环境下抗拉强度缓慢下降。结论在拉应力影响下U型样的腐蚀进程随大气污染物的不同,腐蚀程度不同,拉伸试样的抗拉强度随腐蚀进程的发展而呈周期性衰减。

  16. Interpretation of the Sedimentary Environments of National Oceanic and Atmospheric Administration (NOAA) H11320 Sidescan Sonar Mosaic in Rhode Island Sound (H11320ENVIRONS)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  17. Interpretation of the Sedimentary Environments of National Oceanic and Atmospheric Administration (NOAA) Survey H11321, Central Rhode Island Sound (H11321ENVIRONS shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  18. Interpretation of the Sedimentary Environments of National Oceanic and Atmospheric Administration (NOAA) Survey H11322, Western Rhode Island Sound (H11322ENVIRONS, Geographic)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey (USGS) is working cooperatively with the National Oceanic and Atmospheric Administration (NOAA) to interpret the surficial geology in...

  19. Summary of the results from the Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment (LADEE) Mission

    Science.gov (United States)

    Horanyi, Mihaly

    2016-07-01

    The Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission (9/2013 - 4/2014) discovered a permanently present dust cloud engulfing the Moon. The size, velocity, and density distributions of the dust particles are consistent with ejecta clouds generated from the continual bombardment of the lunar surface by sporadic interplanetary dust particles. Intermittent density enhancements were observed during several of the annual meteoroid streams, especially during the Geminids. LDEX found no evidence of the expected density enhancements over the terminators where electrostatic processes were predicted to efficiently loft small grains. LDEX is an impact ionization dust detector, it captures coincident signals and full waveforms to reliably identify dust impacts. LDEX recorded average impact rates of approximately 1 and 0.1 hits/minute of particles with impact charges of q > 0.5 and q > 5 fC, corresponding to particles with radii of a > 0.3 and a> 0.7~μm, respectively. Several of the yearly meteor showers generated sustained elevated levels of impact rates, especially if their radiant direction intersected the lunar surface near the equatorial plane, greatly enhancing the probability of crossing their ejecta plumes. The characteristic velocities of dust particles in the cloud are on the order of ~100 m/s which we neglect compared to the typical spacecraft speeds of 1.6 km/s. Hence, with the knowledge of the spacecraft orbit and attitude, impact rates can be directly turned into particle densities as functions of time and position. LDEX observations are the first to identify the ejecta clouds around the Moon sustained by the continual bombardment of interplanetary dust particles. Most of the dust particles generated in impacts have insufficient energy to escape and follow ballistic orbits, returning to the surface, 'gardening' the regolith. Similar ejecta clouds are expected to engulf all airless planetary objects, including

  20. Winter observations of CO2 exchange between sea ice and the atmosphere in a coastal fjord environment

    Science.gov (United States)

    Sievers, J.; Sørensen, L. L.; Papakyriakou, T.; Else, B.; Sejr, M. K.; Haubjerg Søgaard, D.; Barber, D.; Rysgaard, S.

    2015-08-01

    Eddy covariance observations of CO2 fluxes were conducted during March-April 2012 in a temporally sequential order for 8, 4 and 30 days, respectively, at three locations on fast sea ice and on newly formed polynya ice in a coastal fjord environment in northeast Greenland. CO2 fluxes at the sites characterized by fast sea ice (ICEI and DNB) were found to increasingly reflect periods of strong outgassing in accordance with the progression of springtime warming and the occurrence of strong wind events: FCO2ICE1 = 1.73 ± 5 mmol m-2 day-1 and FCO2DNB = 8.64 ± 39.64 mmol m-2 day-1, while CO2 fluxes at the polynya site (POLYI) were found to generally reflect uptake FCO2POLY1 = -9.97 ± 19.8 mmol m-2 day-1. Values given are the mean and standard deviation, and negative/positive values indicate uptake/outgassing, respectively. A diurnal correlation analysis supports a significant connection between site energetics and CO2 fluxes linked to a number of possible thermally driven processes, which are thought to change the pCO2 gradient at the snow-ice interface. The relative influence of these processes on atmospheric exchanges likely depends on the thickness of the ice. Specifically, the study indicates a predominant influence of brine volume expansion/contraction, brine dissolution/concentration and calcium carbonate formation/dissolution at sites characterized by a thick sea-ice cover, such that surface warming leads to an uptake of CO2 and vice versa, while convective overturning within the sea-ice brines dominate at sites characterized by comparatively thin sea-ice cover, such that nighttime surface cooling leads to an uptake of CO2 to the extent permitted by simultaneous formation of superimposed ice in the lower snow column.

  1. Investigation on the development of measurement techniques, the behavior in the environment and the estimation of internal radiation dose by inhalation for some typical atmospheric radionuclides

    International Nuclear Information System (INIS)

    Radionuclides in surface atmosphere on the earth are 222Rn, 220Rn and their short lived progeny, 7Be, 85Kr, 3H, 14C, 137Cs, 90Sr and so on. In this paper, among them, 222Rn, their short lived progeny (218Po, 214Pb, 214Bi, 214Po), 7Be, 3H, and 90Sr are focused on as follows based on the experimental and observed results, 1. Development of their measurement techniques, 2. Analysis of their variation of atmospheric concentration with time and places, 3. Analysis of their interaction characteristics with surface environment including plants, 4. Estimation of internal radiation doses by inhalation of them. (author). 228 refs

  2. Environment

    Czech Academy of Sciences Publication Activity Database

    Tošovská, Eva

    Prague: Charles University in Prague, Center for Economic Research and Graduate Education , 2006 - (Zemčík, P.; Žigić, K.), s. 62-66 ISBN 80-7343-110-6 Institutional research plan: CEZ:AV0Z70850503 Keywords : environment * Czech Republic Subject RIV: AH - Economics http://www.cerge-ei.cz/publications/books/

  3. Basic neutronics. Neutrons migration

    International Nuclear Information System (INIS)

    This article presents the basic neutronics necessary for the understanding of the operation of the different types of nuclear reactors: 1 - introduction to neutronics: principle of fission chain reactions, fast neutron reactors and thermal neutron reactors, capture, neutron status, variations with the reactor lattices; 2 - Boltzmann equation: neutrons population, neutrons migration, characterization of neutrons population and reactions, integral form of the Boltzmann equation, integral-differential form, equivalence between the two forms; 3 - reactor kinetics: fast neutrons and delayed neutrons, kinetic equations in punctual model, Nordheim equation, reactivity jumps, reactivity ramp; 4 - diffusion equation: local neutron status, Fick's law, diffusion equation, initial, boundary and interface conditions, nuclei in infinite and homogenous medium, some examples of solutions, developments in Eigenmodes; 5 - one-group theory: equation of the 'one-group - diffusion' theory, critical condition of the naked and homogenous reactor, critical condition of a reactor with reflectors, generalizations; 6 - neutrons moderation: different moderation mechanisms, elastic shock laws, moderation equation, some examples of solutions; 7 - resonance absorption of neutrons: advantage of the discontinuous moderation character, advantage of an heterogenous disposition, classical formula of the anti-trap factor in homogenous and heterogenous situation; 8 - neutrons thermalization: notions of thermalization mechanisms, thermalization equation, Maxwell spectrum, real spectrum, classical formula of the thermal utilisation factor, classical formula of the reproduction factor, moderation optimum. (J.S.)

  4. Life extinctions by neutron star mergers

    CERN Document Server

    Dar, Arnon; Shaviv, N J; Dar, Arnon; Laor, Ari; Shaviv, Nir J.

    1997-01-01

    High energy cosmic ray jets from nearby mergers or accretion induced collapse (AIC) of neutron stars (NS) that hit the atmosphere can produce lethal fluxes of atmospheric muons at ground level, underground and underwater, destroy the ozone layer and radioactivate the environment. They could have caused most of the massive life extinctions on planet Earth in the past 600 My. Biological mutations due to ionizing radiations could have caused the fast appearance of new species after the massive extinctions. An early warning of future extinctions due to NS mergers may be obtained by identifying, mapping and timing all the nearby binary neutron stars systems. A warning of an approaching cosmic ray burst from a nearby NS merger/AIC may be provided by a very intense gamma ray burst which preceeds it.

  5. Progress of Neutron Bubble Detectors in CIAE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Neutron bubble detector is the only personal neutron dosimeter which has adequate neutronsensitivity to meet the implications of the ICRP 60 recommendations for neutron dosimetry. It canmonitor the wide range of neutron energy, for example 100 eV to 10 MeV And it becomes a significanttool for neutron dose monitoring at the environment of nuclear energy.

  6. Neutron production during thunderstorms

    International Nuclear Information System (INIS)

    We have analyzed the neutron fluxes correlated with thunderstorm activity recently measured at mountain altitudes by Tien-Shan, Tibet and Aragats groups. We perform simulations of the photonuclear reactions of gamma rays born in the electron-gamma ray avalanches in the thunderstorm atmosphere and calculate expected count rates of the neutron counters used by 3 groups. Our analysis supported the Tibet group conclusion on the photonuclear nature of thunderstorm-correlated neutrons. The photonuclear reactions of the gamma rays born in the electron-photon avalanches in the thunderstorm atmospheres interacting in the lead producer of a Neutron monitor can provide neutron yield compatible with additional count of NM at least for the largest Thunderstorm Ground Enhancements (TGEs).

  7. Pacific Northwest Laboratory annual report for 1980 to the DOE Assistant Secretary for Environment. Part 3. Atmospheric sciences

    International Nuclear Information System (INIS)

    Separate absracts were prepared for the 15 sections of this progress report which is a description of atmospheric research at PNL organized in terms of the following energy technologies: coal, gas and oil; fission and fusion; and oil shale

  8. Effects of environment and frequency on the fatigue behavior of the spallation neutron source (SNS) target container material - 316 LN stainless steel

    Science.gov (United States)

    Tian, Hongbo

    As the candidate target container material of the new Spallation Neutron Source (SNS) being designed and constructed at the Oak Ridge National Laboratory (ORNL), Type 316 low-carbon nitrogen-added (LN) stainless steel (SS) will operate in an aggressive environment, subjected to intense fluxes of high-energy protons and neutrons while exposed to liquid mercury. The current project is oriented toward materials studies regarding the effects of test environment and frequency on the fatigue behavior of 316 LN SS. In order to study the structural applications of this material and improve the fundamental understanding of the fatigue damage mechanisms, fatigue tests were performed in air and mercury environments at various frequencies and R ratios (R = sigma min/sigmamax, sigmamin and sigmamax are the applied minimum and maximum stresses, respectively). Fatigue data were developed for the structural design and engineering applications of this material. Specifically, high-cycle fatigue tests, fatigue crack-propagation tests, and ultrahigh cycle fatigue tests up to 10 9 cycles were conducted in air and mercury with test frequencies from 10 Hz to 700 Hz. Microstructure characterizations were performed using optical microscopy (OM), scanning-electron microscopy (SEM), and transmission-electron microscopy (TEM). It was found that mercury doesn't seem to have a large impact on the crack-initiation behavior of 316 LN SS. However, the crack-propagation mechanisms in air and mercury are different in some test conditions. Transgranular cracks seem to be the main mechanism in air, and intergranular in mercury. A significant specimen self-heating effect was found during high-cycle faituge. Theoretical calculation was performed to predict temperature responses of the material subjected to cyclic deformation. The predicted cyclic temperature evolution seems to be in good agreement with the experimental results.

  9. Atmospheric Environment Fabrication of Composite Films by Ethanol Catalytic Combustion and Its Use as Counter Electrodes for Dye-Sensitized Soar Cells

    OpenAIRE

    Xiaoping Zou; Cuiliu Wei

    2014-01-01

    The composite films which consist of amorphous carbon, carbon nanotube, and iron nanoparticles were prepared by ethanol catalytic combustion in atmospheric environment. The as-prepared composite films have good electrocatalytic activity and high conductivity which is due to their particular structure. The efficiency of the composite films based dye-sensitized soar cells (DSSCs) is closed to that of the Pt based one. Most importantly, the DSSC employing the composite films presents a higher FF...

  10. Observations of the UARS Particle Environment Monitor and computation of ionization rates in the middle and upper atmosphere during a geomagnetic storm

    Science.gov (United States)

    Sharber, J. R.; Frahm, R. A.; Winningham, J. D.; Biard, J. C.; Lummerzheim, D.; Rees, M. H.; Chenette, D. L.; Gaines, E. E.; Nightingale, R. W.; Imhof, W. L.

    1993-01-01

    In this paper we present observations made by the Particle Environment Monitor (PEM) instruments during the geomagnetic storm of 8-9 November, 1991. Ionization and energy deposition rates as functions of altitude in the middle and upper atmosphere by incident electrons and positive ions in the storm interval are computed. The suite of PEM instruments provides a systematic measurement of energetic particles and their associated X-rays over an energy range not fully covered by previous satellite missions.

  11. A time series approach to the correction for atmosphere effects and the significance of a semi-diurnal variation in corrected intensities of secondary cosmic ray neutrons and mesons (NM64 and MT64)

    International Nuclear Information System (INIS)

    The aim of this research was to distinguish as accurately as possible between two mechanisms behind a half-daily variation in detected numbers of neutrons and mesons in the secondary cosmic ray particles at sea level. These two mechanisms are due to air pressure variations at sea level and affect the number of primary particles with a certain arrival direction. The distribution among arrival directions in the ecliptic plane varies if a gradient exists in the guiding centre density of primaries in directions perpendicular to the neutral sheet. Chapter 2 is devoted to the calculation of a physically and statistically justifiable determination of the barometric coefficient for neutron measurements and air pressures. Chapter 3 deals with the estimation of atmospheric correction coefficients for the elimination of the influence of changing atmospheric conditions on the number of detected mesons. For mesons the variation of total mass, and also the variations in mass-distribution along the trajectory of the mesons are important. After correction for atmospheric variations using the resulting atmospheric correction coefficients from chapter 2 and 3, the influence of the structure of the interplanetary magnetic field near the earth is examined in chapter 4. 0inally, in chapter 5, a power spectral analysis of variations in corrected intensities of neutrons and mesons is carried out. Such an analysis distinguishes the variance of a time series into contributions within small frequency intervals. From the power spectra of variations on a yearly basis, a statistically fundamented judgement can be given as to the significance of the semi-diurnal variation during the different phases of the solar magnetic activity cycle. (Auth.)

  12. Possible use of EPDM in radioactive waste disposal: Long term low dose rate and short term high dose rate irradiation in aquatic and atmospheric environment

    International Nuclear Information System (INIS)

    In this study, changes in the properties of ethylene propylene diene terpolymer (EPDM) irradiated with different dose rates in ambient atmosphere and aqueous environment were investigated. Irradiations were carried out both with low dose and high dose rate irradiation sources. EPDM samples which were differentiated from each other by peroxide type and 5-ethylidene 2-norbornene (ENB) contents were used. Long term low dose rate irradiations were carried out for the duration of up to 2.5 years (total dose of 1178 kGy) in two different irradiation environments. Dose rates (both high and low), irradiation environments (in aquatic and open to atmosphere), and peroxide types (aliphatic or aromatic) were the parameters studied. Characterization of irradiated EPDM samples were performed by hardness, compression, tensile, dynamic mechanical analysis (DMA), TGA–FTIR, ATR-FTIR, XRD and SEM tests. It was observed that the irradiation in water environment led to a lower degree of degradation when compared to that of irradiation open to atmosphere for the same irradiation dose. In addition, irradiation environment, peroxide type and dose rate had effects on the extent of change in the properties of EPDM. It was observed that EPDM is relatively radiation resistant and a candidate polymer for usage in radioactive waste management. - Highlights: ► Possible use of EPDM in radioactive waste management was studied. ► The low dose rate irradiations were carried out for duration of up to 2.5 years. ► Characterizations of irradiated samples were performed. ► EPDM could possibly be a candidate material to be used in the radioactive waste management.

  13. Neutron scattering facilities at the research reactor DR3

    International Nuclear Information System (INIS)

    DR3 is a heavy-water-moderated 10 MW thermal neutron research reactor. The 26 fuel elements contain 2.5-3.5 kg uranium enriched to less than 20% 235U. Neutron beams emerge from four horizontal through-tubes tangential to the reactor core. Two of the horizontal tubes are used for neutron scattering experiments in the field of materials research. The vertical tubes are predominantly used for isotope production and materials testing. The thermal neutron flux is about 3.5x1013 n/cm2/s in the centre of the 7-inch diameter horizontal through-tubes. The thermal neutron flux in equilibrium with the D2O moderator (50 deg. C) has a nearly Maxwellian distribution peaking at 1.1 A. At the maximum flux position in the two horizontal through-tubes used for materials research are installed scatterers designed with a considerably higher scattering power for thermal neutrons than for fast neutrons and gamma-rays. The scatterer is either a 10 mm slab of light water, providing a nearly thermal Maxweellian spectrum at the beam port, or a chamber filled with supercritical hydrogen gas at 16 atmospheres and 38 K, a so-called cold neutron source. The spectrum from a cold source has a considerable flux enhancement in the long wavelength region when compared to the thermal water scatterer. Neutron beams are available for materials research from two thermal and two cold beam ports in the Reactor Hall. One of the cold beams is shared with a 20 meter long cold-neutron guide-tube which provides three beam ports in a separate building, the Neutron House, with could neutrons. Only neutrons that have undergone total reflection from the Ni-coated glass plates in the bent guide-tube arrive at the end of the guide tube in the Neutron House. The angle of total reflection is proportional to the neutron wavelength. Therefore almost no neutrons of wavelength below a certain ''critical'' wavelength are transmitted through the guide-tube, and the experimental equipment installed in the Neutron Houyse

  14. Thermoluminescent detectors for neutron dosimetry at high altitudes

    International Nuclear Information System (INIS)

    At high altitudes in the earth's atmosphere cosmic-ray induced neutrons become the dominant contributors to the biologically relevant dose equivalent. Depending on the geomagnetic latitude and the solar activity cycle, neutron dose onboard aircraft amounts, for example, to roughly 50 to 70 % of the overall dose equivalent. Neutron detection in complexly mixed radiation environments by means of active, i.e. power-consuming, detectors is commonly aggravated by the fact that a variety of charged particles present in the field cannot be discriminated and therefore biases the measurement. Passive thermoluminescent dosemeters (TLDs) are proposed as a convenient alternative. They are easy-to-handle in practical use, contain no flammable gases and emit no electromagnetic radiation that could interfere with sensitive electronics. The simultaneous application of specific detector types is known in neutron dosimetry as the pair method. Neutron-sensitive TLD-600 (6LiF) is combined with TLD-700 (7LiF) which is almost insensitive to neutrons. The sensitivity for all other radiations is identical for both types, so that a simple subtraction of the measured detector signals leads to the thermal neutron dose. As the neutron cross sections of 6Li and 7Li differ significantly only below 200 keV, the pair method in its conventional form assesses the dose only from neutrons in this energy region. The method can be extended for utilization at high altitudes, such as onboard aircraft, if the calibration of the TLDs is performed in a reference field which simulates in close proximity the atmospheric neutron environment. For our purposes we used the CERN-EU High-Energy Reference Field (CERF) for which the relative contribution of neutrons with energies below 200 keV to the entire fluence is practically the same as for the cosmic-ray induced neutron spectrum. Measurements with Bonner sphere spectrometers at the CERF facility and onboard aircraft and subsequent comparison with a FLUKA Monte

  15. Neutron field characteristics of Ciemat's Neutron Standards Laboratory Hector Rene Vega-Carrillo

    OpenAIRE

    Guzmán-García, Karen Arlete; Méndez Villafañe, Roberto; Vega-Carrillo, Héctor René

    2015-01-01

    Monte Carlo calculations were carried out to characterize the neutron field produced by the calibration neutron sources of the Neutron Standards Laboratory at the Research Center for Energy, Environment and Technology (CIEMAT) in Spain. For 241AmBe and 252Cf neutron sources, the neutron spectra, the ambient dose equivalent rates and the total neutron fluence rates were estimated. In the calibration hall, there are several items that modify the neutron field. To evaluate their effects differen...

  16. Application of API method in atmosphere environment evaluation%API法在城市大气环境质量评价中的应用

    Institute of Scientific and Technical Information of China (English)

    石建屏; 李新

    2012-01-01

    The paper adopts atmosphere pollution index(API) to evaluate the atmosphere environment quality of Mianyang city in 2008.The result shows that the atmosphere of this city has reached the Ⅱrank national standard in 2008.The main contamination which affects the atmosphere quality in this city is absorbable particle(PM10).And the main affect periods are May,January,February,March,May and December.The affect factors are weather and factitious activities.Therefore,it is suggested that factories should adopt some prevention and cure countermeasures for pollution,such as,to adopt the optimize industry structure,alteration of boiler,and combustion of equipments;to develop and generalize the using of cleanness energy sources energetically;to quick up the virescence in city.To be compared with other evaluation methods,adopting atmosphere pollution index(API) to evaluate the atmosphere environment quality could correctly open out the atmosphere pollution extent,so API is a simple,straight,credible evaluation method.%采用空气污染指数API法对绵阳市2008年大气环境质量进行评价。结果表明,该市空气质量达到了国家二级标准,影响空气质量的主要污染物为可吸入颗粒物(PM10),主要污染时间为1、2、3、5、12月,影响因素为气象和人为活动。建议采取优化产业结构、改造锅炉和燃烧设备、大力发展和推广使用清洁能源、加快城市绿化建设等污染防治对策。API法与其他评价方法相比,可以准确地揭示大气污染程度,是一种简便、直观且可靠的评价方法。

  17. 变电站周围大气腐蚀环境检测分析%Detection and Analysis of Atmospheric Corrosion Environment Around Substation

    Institute of Scientific and Technical Information of China (English)

    王平; 宋国升; 孙心利; 周慧波

    2013-01-01

    This paper analyzed the characteristics of atmospheric corrosion and the sources of pollutants and it was concluded that atmospheric environment detection was an important part in substation equipment corrosion analysis. Through detection and analysis of atmospheric environment around substation, the substation metal material corrosion was mainly due to the high gas composition of H2S, NH3 generated by the production sites around substation, such as sewage, chemical plants, chicken farms. This paper also proposed the prevention and treatment measures, such as strengthening environmental detection, conducting environmental assessment, etc.%  要:分析大气腐蚀的特点及污染物的来源后认为,开展大气环境检测是进行变电站设备腐蚀原因分析的重要内容。通过对某变电站周围大气环境的检测和分析,提出了导致变电站金属材料腐蚀的主要原因在于周围污水、化工厂、养鸡场等生产场所产生的H2S、NH3等气体成分过高所致,同时提出了应加强环境检测、开展环境评价等预防和处理措施建议。

  18. Atmospheric dispersion of an elevated release in a rural environment: Comparison between field SF 6 tracer measurements and computations of Briggs and ADMS models

    Science.gov (United States)

    Connan, O.; Leroy, C.; Derkx, F.; Maro, D.; Hébert, D.; Roupsard, P.; Rozet, M.

    2011-12-01

    The French Institute for Radiological Protection and Nuclear Safety (IRSN), in collaboration with VEOLIA (French environmental services company), conducted experimental campaigns to study atmospheric dispersion around an Energy Recycling Unit (EUR). The objectives were to study dispersion for an elevated release in a rural environment and to compare results with those of models. The atmospheric dispersion was studied by SF 6 tracer injection into a 40 m high stack. Maximum values of experimental Atmospheric Transfer Coefficients (ATC max) and horizontal dispersion standard deviations ( σh) were compared to predictions from a first generation Briggs gaussian model as well as results from the latest generation ADMS 4.1 gaussian model. In neutral atmospheric conditions, the Briggs and ADMS models are in good agreement with experimental data in terms of ATC and σh. In unstable condition, for σh, both ADMS and Briggs models slightly overestimate the data for winter and summer conditions. In unstable conditions, ADMS and Briggs models overestimated ATC max. The statistical evaluation of the models versus experimental data shows neither models ever meets all of the criteria for good performance. However, statistical evaluation indicates that the ADMS model is more suitable for neutral condition, and that the Briggs model is more reliable for summer unstable conditions.

  19. Classiifcation and Evaluation of Environment of Atmospheric Corrosion%大气腐蚀环境的分类及腐蚀性评定

    Institute of Scientific and Technical Information of China (English)

    刘凯吉

    2015-01-01

    本文主要介绍了大气腐蚀的原理和构成大气腐蚀的各种腐蚀要素,根据相对湿度和污染物因素确定了大气腐蚀的类型,同时,综合考虑各种腐蚀要素,根据环境腐蚀的严酷性程度对腐蚀环境进行分类.%In this paper, the principle and various factors of atmospheric corrosion were introduced and the types of atmospheric corrosion were determined based on the corrosion relative humidity and pollutant factors, meanwhile, environment of corrosion was classified considering severity of all kinds of corrosion factors.

  20. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    . Nevertheless, people’s experience of the environment is sought manipulated in a variety of contexts, often without offering a less ‘true’ experience of a situation than if it had not been manipulated by people. In fact, orchestrations of space are often central to sociality, politics and aesthetics. This...... introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  1. Miniaturized, Multi-Analyte Sensor Array for the Automated Monitoring of Major Atmospheric Constituents in Spacecraft Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — InnoSense LLC (ISL) proposes to develop a miniaturized, multi-analyte sensor for near real-time monitoring of analytes in the spacecraft environment. The proposed...

  2. Improving the Representation of the Nocturnal Near-Neutral Surface Layer in the Urban Environment with a Mesoscale Atmospheric Model

    Science.gov (United States)

    Husain, Syed Zahid; Bélair, Stéphane; Mailhot, Jocelyn; Leroyer, Sylvie

    2013-06-01

    A new approach to improve the representation of surface processes in the Global Environmental Multiscale (GEM) atmospheric model associated with the exchanges between the urban canopy and the atmosphere is presented. Effects of the urban canopy on the evolution of surface-layer wind, temperature, moisture, and turbulence are directly parametrized in order to allow realistic interactions between the canopy elements (i.e., roofs, roads, and walls) and the atmosphere at GEM's multiple vertical levels that are positioned inside the canopy. Surface energy budgets as implemented in the Town Energy Balance (TEB) scheme have been used to determine temperatures of the urban canopy elements for the proposed multilayer scheme. Performance of the multilayer scheme is compared against standard implementations of the TEB scheme for one nighttime intensive observation period of the Joint Urban 2003 experiment held in Oklahoma City, USA. Although the new approach is found to have a negligible impact on urban surface-layer wind profiles, it improves the prediction of near-neutral nocturnal profiles of potential temperature close to the surface. The urban heat island effect is simulated with a better accuracy by the multilayer approach. The horizontal temperature gradient across the central business district of the city along the direction of flow is also reasonably well captured by the proposed scheme.

  3. Dynamics of contamination of an atmospheric air on the database of the network of a radiation control and environment monitoring on the Belarus

    International Nuclear Information System (INIS)

    The system of the radiation control and monitoring of the natural environment which are carried out by Department of hydrometeorology of the Ministry of natural resources and preservation of the environment, includes supervision over pollution of surface waters, bottom sediments, atmospheric air and soil by radionuclides. Supervision is realized at 57 servers, where exposure gamma rate (EDR) is daily measured. The radioactive fallout's from atmospheric air are controlled with use of horizontal plane tables on 30 servers located on all the territory of the Republic. In five towns of Belarus (Minsk, Mogilev, Gomel, Brest, Pinsk) a content of radioactive aerosols in the air is daily measured with the use of the filter-ventilating station In the first period of the catastrophe the levels of exposure gamma rate in Bragin have made - 46000 micro R/h (distance up to Chernobyl NPP - 50 kms), in Chechersk - 10000 micro R/h (distance up to Chernobyl NPP - 180 kms) In June 2002 the maximum single levels were fixed in Bragin - 105 micro R/h and in July in Chechersk - 32 micro R/h. On the rest of the territory the exposure doze rate of gamma - radiation does not exceed the levels of natural gamma - hum noise (up to 20 micro R/h). In regional towns the average annual levels have made from 10 up to 15 micro R/h. The statistical data processing of measurements of exposure gamma rate in 10 most typical the settlements shows, that two groups of the settlements can be selected: with low values EDR up to 20 micro R/h: Lel'chitsy, Mozyr', Slutsk, Mogilev, Pinsk and with values EDR more than 20 micro R/h: Slavgorod, Khojniki, Bragin, Chechersk and Narovlya. The analysis of outcomes of observations behind a state of an atmospheric air has shown, that in 2002 it is not revealed short-lived radionuclides, is not marked of essential changes in behavior cesium-137 and strontium -90 in an atmosphere in comparison with the previous years in post-accident period. Investigation, which are

  4. Transformations in neutron powder diffraction

    International Nuclear Information System (INIS)

    The major milestone in neutron powder diffraction occurred thirty years ago with the advent of the Rietveld method of structure refinement. The combination of advances in both instrumentation and computing power allowed moderately complex low-symmetry structures to be analysed by powder methods for the first time. Over the past five years there have been further transformations in neutron powder diffraction again resulting from combined developments in instrumentation and data analysis methods. In this paper we shall focus on high resolution, high intensity time-of-flight neutron powder diffraction and the impact that this technique has had on our understanding of the structural aspects of phase transitions and phase transformations. The essentially constant Δd/d resolution that is intrinsic to a time-of-flight diffractometry implies that peak splittings arising from a structural phase transition are observed with equal resolution at all orders of reflection, thus maximising the information content associated with structural distortions. Additionally, the fixed diffraction geometry permits the use of sophisticated sample environments such as high pressure cells and special atmosphere furnaces without contamination of the sample diffraction pattern. (orig.)

  5. Climate and atmospheric modeling studies. Climate applications of Earth and planetary observations. Chemistry of Earth and environment

    Science.gov (United States)

    1990-01-01

    The research conducted during the past year in the climate and atmospheric modeling programs concentrated on the development of appropriate atmospheric and upper ocean models, and preliminary applications of these models. Principal models are a one-dimensional radiative-convective model, a three-dimensional global climate model, and an upper ocean model. Principal applications have been the study of the impact of CO2, aerosols and the solar 'constant' on climate. Progress was made in the 3-D model development towards physically realistic treatment of these processes. In particular, a map of soil classifications on 1 degree x 1 degree resolution has been digitized, and soil properties have been assigned to each soil type. Using this information about soil properties, a method was developed to simulate the hydraulic behavior of soils of the world. This improved treatment of soil hydrology, together with the seasonally varying vegetation cover, will provide a more realistic study of the role of the terrestrial biota in climate change. A new version of the climate model was created which follows the isotopes of water and sources of water (or colored water) throughout the planet. Each isotope or colored water source is a fraction of the climate model's water. It participates in condensation and surface evaporation at different fractionation rates and is transported by the dynamics. A major benefit of this project has been to improve the programming techniques and physical simulation of the water vapor budget of the climate model.

  6. Laser diagnostics on atmospheric-pressure low-temperature helium pulsed plasmas in room- and cryogenic-temperature environments

    Science.gov (United States)

    Sakakibara, Noritaka; Muneoka, Hitoshi; Urabe, Keiichiro; Yasui, Ryoma; Terashima, Kazuo

    2015-09-01

    In atmospheric-pressure low- temperature plasmas, the control of the plasma gas temperature (Tg) by a few kelvin is considered to be crucial for their applications to novel materials processing such as bio-materials. However, there have been only few studies that focused on the influence of Tg on the plasma characteristics. On the other hand, it was reported that helium metastables played a key role in the dependency of chemical reactions on Tg in helium-nitrogen plasmas. In this study, laser diagnostics were carried out in atmospheric-pressure helium pulsed plasmas near or below room temperature, at 340 -100 K. Parallel electrodes of copper rods (diameter: 2 mm) with a gap distance of 535 μm were used and pulsed discharges with a pulse width of a few hundred nanoseconds were generated inside a reactor. The density and lifetime of helium metastables were estimated by laser absorption spectroscopy measurements and Tg was evaluated by near-infrared laser heterodyne interferometry measurements. At 300 K, the helium metastable density was 1.5 × 1013 cm-3 while the lifetime was 3.1 μs, and increase in Tg was up to 70 K. Dependency of the density and lifetime of helium metastables on Tg was observed and also discussed.

  7. Development of coupled models for regional water cycle and material transport in the atmospheric, terrestrial, and oceanic environment

    International Nuclear Information System (INIS)

    Numerical simulations are the effective approach to investigate the complex mechanism in environmental phenomena and many numerical models have been developed for specific applications over wide range of field. Recently, much effort has been made to develop numerical models that can deal with the multi-physics problems in the complex environmental system. Most of these models are constructed by coupling existing models developed separately for their specific field of studies and called as coupled models. A general-purpose model coupling program of Japan Atomic Energy Agency (JAEA-Coupler) has been developed to construct local to regional scale coupled models for environmental studies. In these coupled models, calculations of component models are carried out by different processors of parallel computers in the same manner as their original stand-alone calculations and the coupler controls these processes and handles data exchanges among component models using Message Passing Interface (MPI). Data exchanges are only conducted between the coupler and each component model and the coupler handles the data distribution to target models with interfacing spatial, temporal, and physical discrepancies among component models. By using JAEA-Coupler, integrated coupled models to simulate regional water cycle and material transport have been constructed. The coupled model for regional water cycle consists of the non-hydrostatic atmospheric dynamic model of PSU/NCAR (MM5), detailed multi-layer land surface model (SOLVEG) and three-dimensional hydrology model (RIVERS) developed at JAEA, the third-generation ocean wind-wave model of NOAA (WW3), and the Princeton Ocean Model (POM). For the material transport, Lagrangian particle dispersion models for the atmosphere and ocean (GEARN and SEA-GEARN, respectively) developed at JAEA are incorporated into the water cycle coupled model, where RIVERS includes the function to calculate material transport. Test calculations were carried out

  8. A ToF-SIMS investigation of the corrosion behavior of Mg alloy AM50 in atmospheric environments

    Science.gov (United States)

    Esmaily, M.; Malmberg, P.; Shahabi-Navid, M.; Svensson, J. E.; Johansson, L. G.

    2016-01-01

    The redistribution of chloride and sodium ions after the NaCl-induced atmospheric corrosion of Mg alloy AM50 was investigated by means of Time-of-Flight Ion Mass Spectroscopy (ToF-SIMS). The samples were exposed at -4 and 22 °C in the presence of 400 ppm CO2. The results confirm the presence of less conductive electrolyte, and thus, less movement of ionic species (including sodium and chloride) in the electrolyte layer formed on the surface of samples exposed at the sub-zero temperature. Besides, ToF-SIMS analysis showed the presence of an Al-containing surface film formed on the alloy surface after exposure at high relative humidity.

  9. EFFECT OF CHLORIDE ON THE ATMOSPHERIC CORROSION OF SIMULATED ARTIFACT IRON IN NO3-BEARING POLLUTANT ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    X. Cao; C.C. Xu

    2006-01-01

    The effect of chloride in nitrogen-bearing pollutant on the atmospheric corrosion of cast iron was investigated by using periodic wet-dry test, electrochemical experiment and surface tension test.Scanning electron microscopy (SEM) with energy disperse atomic X-ray (EDAX) was used to identify the corrosion processes and products. The results of the weight loss measurement showed that the whole corrosion kinetics can be approximately described by: AW=AtB. With the addition of NaC1, B increases. The result presented that Cl- accelerated the corrosion rate obviously during the whole corrosion process. The initial corrosion process was investigated from the viewpoint of surface tension. At the initial corrosion period, the corrosion rate was proportion to the adsorption of anions contained the solutions. And as corrosion went on, the penetration effect of anions and different characteristics of the corrosion products began to dominant the corrosion process, which led to the accelerated effect.

  10. ModObs: Atmospheric modelling for wind energy, climate and environment applications : exploring added value from new observation technique

    Science.gov (United States)

    Sempreviva, A. M.

    2009-04-01

    The EC FP6 Marie Curie Training Network "ModObs" http://www.modobs.windeng.net addresses the improvement of atmospheric boundary layer (ABL) models to investigate the interplay of processes at different temporal and spatial scales, and to explore the added value from new observation techniques. The overall goal is to bring young scientists to work together with experienced researchers in developing a better interaction amongst scientific communities of modelers and experimentalists, using a comprehensive approach to "Climate Change", "Clean Energy assessment" and "Environmental Policies", issues. This poster describes the work in progress of ten students, funded by the network, under the supervision of a team of scientists within atmospheric physics, engineering and satellite remote sensing and end-users such as companies in the private sector, all with the appropriate expertise to integrate the most advanced research methods and techniques in the following topics. MODELING: GLOBAL-TO-MESO SCALE: Analytical and process oriented numerical models will be used to study the interaction between the atmosphere and the ocean on a regional scale. Initial results indicate an interaction between the intensity of polar lows and the subsurface warm core often present in the Nordic Seas (11). The presence of waves, mainly swell, influence the MABL fluxes and turbulence structure. The regional and global wave effect on the atmosphere will be also studied and quantified (7) MESO-SCALE: Applicability of the planetary boundary layer (PBL) parametrizations in the meso-scale WRF model to marine atmospheric boundary layer (MABL) over the North Sea is investigated. The most suitable existing PBL parametrization will be additionally improved and used for downscaling North Sea past and future climates (2). Application of the meso-scale model (MM5 and WRF) for the wind energy in off-shore and coastal area. Set-up of the meso-scale model, post-processing and verification of the data from

  11. Atmosphere Environment Simulation Scenario Generator for Distributed Simulation System%大气环境仿真剧情生成系统

    Institute of Scientific and Technical Information of China (English)

    张鹏; 龚光红

    2008-01-01

    The Atmosphere Environment Simulation Scenario Generator (AESSG) is designed to help users to extract simulation scenario. It is convenient and fast for user to construct the simulation federation based on HLA. It is allowed to use human language describing the searching condition. AESSG provides the service for users to editing the searching result within reasonable scopes. User interface can provide the environment for users to search and edit environment data. Users can submit the searching condition that specified in human language or in numeric terms. Fuzzy logical technique is introduced to deal with the transition from human language to machine code. The resource database is constructed, which can store multi-resolution atmosphere data and models.%大气环境仿真剧情生成系统(AESSG)辅助用户利用不同来源的大气环境数据生成能够满足仿真需求的大气环境仿真剧情.支持输入人类语言描述的模糊查询条件.模糊检索后查询结果按照符合度来排列,供用户选择.模糊逻辑技术引入到环境信息搜索引擎来实现模糊搜索.AESSG运行时系统作为联邦成员参与仿真联邦的仿真,实时响应联邦内的环境信息请求.大气环境信息资源库支持多来源、多分辨率的大气环境数据与模型的存储.

  12. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    Science.gov (United States)

    Franklyn, C. B.

    2011-12-01

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >1011 nṡs-1. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  13. Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

    Science.gov (United States)

    Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

    2005-01-01

    Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

  14. ATR neutron spectral characterization

    International Nuclear Information System (INIS)

    The Advanced Test Reactor (ATR) at INEL provides intense neutron fields for irradiation-effects testing of reactor material samples, for production of radionuclides used in industrial and medical applications, and for scientific research. Characterization of the neutron environments in the irradiation locations of the ATR has been done by means of neutronics calculations and by means of neutron dosimetry based on the use of neutron activation monitors that are placed in the various irradiation locations. The primary purpose of this report is to present the results of an extensive characterization of several ATR irradiation locations based on neutron dosimetry measurements and on least-squares-adjustment analyses that utilize both neutron dosimetry measurements and neutronics calculations. This report builds upon the previous publications, especially the reference 4 paper. Section 2 provides a brief description of the ATR and it tabulates neutron spectral information for typical irradiation locations, as derived from the more historical neutron dosimetry measurements. Relevant details that pertain to the multigroup neutron spectral characterization are covered in section 3. This discussion includes a presentation on the dosimeter irradiation and analyses and a development of the least-squares adjustment methodology, along with a summary of the results of these analyses. Spectrum-averaged cross sections for neutron monitoring and for displacement-damage prediction in Fe, Cr, and Ni are given in section 4. In addition, section4 includes estimates of damage generation rates for these materials in selected ATR irradiation locations. In section 5, the authors present a brief discussion of the most significant conclusions of this work and comment on its relevance to the present ATR core configuration. Finally, detailed numerical and graphical results for the spectrum-characterization analyses in each irradiation location are provided in the Appendix

  15. Study on the dynamics of halogen elements in the agro-environment and these element`s deficiency, toxicity and environmental hazards by the application of the neutron activation analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Yuita, Kouichi [National Inst. of Agro-Environmental Sciences, Tsukuba, Ibaraki (Japan)

    1998-03-01

    A neutron activation analysis method is an accurate and highly sensitive method for analyzing halogen elements (iodine, bromine and chlorine) except fluorine. It is unsubstitutable and valuable method especially for iodine (including radioactive {sup 129}I) and bromine which are present at lower levels. Halogen elements have high chemical and physiological activities and move widely in the environment. As a result, deficiency and an excess of halogen elements in plants and animals have occurred and artificial halogen compounds have caused environmental pollution in wide areas. We efficiently utilized the neutron activation analysis method and an activable tracer method to obtain valuable findings which contribute to the clarification of and measures against these actual problems and which are also concerned with the occurrence, distribution and migration of halogen elements in the environment, especially agricultural and forestry ecosystems in space and in time. (author)

  16. Damping and Decoherence in Neutron Oscillations

    CERN Document Server

    Kerbikov, B O; Kamyshkov, Y A; Varriano, L J

    2015-01-01

    An analysis is made of the role played by the gas environment in neutron-mirror-neutron and neutron-antineutron oscillations. In the first process the interaction with the ambient medium induces a refraction energy shift which plays the role of an extra magnetic field. In the second process antineutron annihilation in practice might lead to strong decoherence, which should be taken into account in experiments with free neutrons looking for the neutron to antineutron transformation.

  17. Date palm (Phoenix dactylifera L.) leaves as biomonitors of atmospheric metal pollution in arid and semi-arid environments

    International Nuclear Information System (INIS)

    The leaves of date palms were evaluated as a possible biomonitor of heavy metal contamination in Ma'an city, Jordan. Concentrations of (Fe), (Pb), (Zn), (Cu), (Ni), and (Cr) were determined in washed and unwashed leaves and soil samples collected from different sites with different degrees of metal contamination (urban, suburban, industrial, highway and rural sites); separate leaves were taken from outside the city to be used as a control sample. Samples collected from industrial sites were found to have high concentrations of all metals except those of Cu, Ni and Pb, which were found at high levels in the highway site samples which is associated with the road traffic. The difference between unwashed and washed samples showed that metal pollutants exist as contaminants, particularly Pb, Zn and Ni, which varied in concentration, depending on the source of the metal. - Highlights: → High metal concentration in plant samples and roadside soil was due to the heavy traffic. → The mean concentrations (C) were in the order: CFe > CPb > CZn > CNi > CCu > CCr. → Difference between unwashed and washed samples showed that pollutants exist as contaminants. - Date palm (Phoenix dactylifera L.) leaves can be used as an inexpensive biomonitor of the deposition, accumulation and distribution of heavy metal contamination in arid environments.

  18. Nature and sources of particle associated polycyclic aromatic hydrocarbons (PAH) in the atmospheric environment of an urban area

    International Nuclear Information System (INIS)

    The total PAH associated to the airborne particulate matter (PM10) was apportioned by one receptor model based on positive matrix factorization (PMF) in an urban environment (Zaragoza city, Spain) during February 2010–January 2011. Four sources associated with coal combustion, gasoline, vehicular and stationary emissions were identified, allowing a good modelling of the total PAH (R2 = 0.99). A seasonal behaviour of the four factors was obtained with higher concentrations in the cold season. The NE direction was one of the predominant directions showing the negative impact of industrial parks, a paper factory and a highway located in that direction. Samples were classified according to hierarchical cluster analysis obtaining that, episodes with the most negative impact on human health (the highest lifetime cancer risk concentrations), were produced by a higher contribution of stationary and vehicular emissions in winter season favoured by high relative humidity, low temperature and low wind speed. -- Highlights: ► PMF receptor model apportioned four sources associated to the total PAH in Zaragoza. ► The sources were: vehicular, coal combustion, gasoline and stationary emissions. ► Samples were additionally classified according to hierarchical cluster analysis. ► The stationary and vehicular emissions factors showed higher risk for human health. ► Low temperature, wind speed and high relative humidity favoured this negative impact. -- Episodes with the most negative impact on human health regarding PAH were produced by a higher contribution of stationary and vehicular emissions in winter season

  19. Winter observations of CO2 exchange between sea-ice and the atmosphere in a coastal fjord environment

    Directory of Open Access Journals (Sweden)

    J. Sievers

    2015-01-01

    Full Text Available Eddy covariance observations of CO2-fluxes were conducted during March–April 2012 in a temporally sequential order at three locations on fast sea-ice and on newly formed polynya ice in a coastal fjord environment in North East Greenland. CO2 fluxes at the three sites, ICEI, POLYI and DNB, were found to increase over time in accordance with the progression of springtime warming: FCO2ICE1 =1.4 ± 4.9 mmol m−2 d−1, FCO2POLY1 =-3.4 ± 31.4 mmol m−2 d−1 and FCO2DNB =36.7 ± 72.8 mmol m−2 d−1, where values given are the mean and SD, and negative/positive values indicate uptake/outgassing respectively. Observations were carried out at the three sites for 8, 4 and 30 days respectively. A correlation analysis indicates a strong connection between net radiative forcing, wind-speed and CO2-fluxes. Correlations between latent heat fluxes and CO2-fluxes were found for the first time and support the presence of adsorption/desorption processes of CO2 in moist snow.

  20. Atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare, Romania, studied by the moss biomonitoring technique, neutron activation analysis and flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three years' growth of moss or its green part, collected on the ground at 28 sites located 2-17 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons (ENAA) and by flame atomic absorption spectrometry (FAAS). A total of 31 elements were determined, including most of the heavy metals characteristic of emissions from this kind of industry. The observed data for Pb, As, Cu, and Cd are all high compared with those observed in other regions of Europe with similar industries, but the concentrations in moss approach regional background levels at a distance of about 8 km from the main source area. Factor analysis of the data distinguishes two industrial components, one characterized by Pb, Cu, As, and Sb, and another one by Zn and Cd. A strong crustal component including five major elements (Na, Mg, Al, Ti, Fe) and an additional number of trace elements (Sc, V, Cr, Cs, Ba, REE, Th) also appears to be derived mainly from industrial sources. The mean I value in the present material is 5 times lower than the corresponding level in moss in Norway, and also consistently lower than elsewhere in Europe, a fact which evidences the endemic character of the examined area due to iodine depletion. (author)

  1. Atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare, Romania, studied by the moss biomonitoring technique, neutron activation analysis and flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three year's growth of moss or its green part, collected on the ground at 28 sites located 2-17 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons and by flame atomic absorption spectrometry. A total of 31 elements were determined, including most of the heavy metals characteristic of emissions from this kind industry. The observed data for Pb, As, Cu, and Cd are all high compared with those observed in other regions of Europe with similar industries, but the concentrations in moss approach regional background levels at a distance of about 8 km from the main source area. Factor analysis of the data distinguishes two industrial components, one characterized by Pb, Cu, As, and Sb, and another one by Zn and Cd. A strong crustal component including five major elements (Na, Mg, Al, Ti, Fe) and an additional number of trace elements (Sc, V, Cr, Cs, Ba, REE, Th) also appears to be derived mainly from industrial sources. The mean I value in the present material is 5 times lower than the corresponding level in moss in Norway, and also consistently lower than elsewhere in Europe, a fact which evidence the endemic character of the examined area due to iodine depletion

  2. Atmospheric Deposition of Heavy Metals around the Lead and Copper-Zinc Smelters in Baia Mare, Romania, Studied by the Moss Biomonitoring Technique, Neutron Activation Analysis and Flame Atomic Absorption Spectrometry

    CERN Document Server

    Culicov, O A; Steinnes, E; Okina, O S; Santa, Z; Todoran, R

    2002-01-01

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three years' growth of moss or its green part, collected on the ground at 28 sites located 2-17 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons and by flame atomic absorption spectrometry. A total of 31 elements were determined, including most of the heavy metals characteristic of emissions from this kind industry. The observed data for Pb, As, Cu, and Cd are all high compared with those observed in other regions of Europe with similar industries, but the concentrations in moss approach regional background levels at a distance of about 8 km from the main source area. Factor analysis of the data distinguishes two industrial components, one characterized by Pb, Cu, As, and Sb, and another one by Zn and Cd...

  3. Neutron Radiography

    OpenAIRE

    Reddy, A. R.; Rao, M. V. N.

    2012-01-01

    The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  4. Neutron reflectometry

    International Nuclear Information System (INIS)

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  5. Neutron Absorbing Ability Variation in Neutron Absorbing Material Caused by the Neutron Irradiation in Spent Fuel Storage Facility

    International Nuclear Information System (INIS)

    In spent fuel storage facility like high density spent fuel storage racks and dry storage casks, spent fuels are stored with neutron absorbing materials installed as a part of those facilities, and they are used for absorbing neutrons emitted from spent fuels. Usually structural material with neutron absorbing material of racks and casks are located around spent fuels, so it is irradiated by neutrons for long time. Neutron absorbing ability could be changed by the variation of nuclide composition in neutron absorbing material caused by the irradiation of neutrons. So, neutron absorbing materials are continuously faced with spent fuels with boric acid solution or inert gas environment. Major nuclides in neutron absorbing material are Al27, C12, B11, B10 and they are changed to numerous other ones as radioactive decay or neutron absorption reaction. The B10 content in neutron absorbing material dominates the neutron absorbing ability, so, the variation of nuclide composition including the decrease of B10 content is the critical factor on neutron absorbing ability. In this study, neutron flux in spent fuel, the activation of neutron absorbing material and the variation of nuclide composition are calculated. And, the minimum neutron flux causing the decrease of B10 content is calculated in spent fuel storage facility. Finally, the variation of neutron multiplication factor is identified according to the one of B10 content in neutron absorbing material. The minimum neutron flux to impact the neutron absorbing ability is 1010 order, however, usual neutron flux from spent fuel is 108 order. Therefore, even though neutron absorbing material is irradiated for over 40 years, B10 content is little decreased, so, initial neutron absorbing ability could be kept continuously

  6. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  7. On the Response of the Special Sensor Microwave/Imager to the Marine Environment: Implications for Atmospheric Parameter Retrievals. Ph.D. Thesis

    Science.gov (United States)

    Petty, Grant W.

    1990-01-01

    A reasonably rigorous basis for understanding and extracting the physical information content of Special Sensor Microwave/Imager (SSM/I) satellite images of the marine environment is provided. To this end, a comprehensive algebraic parameterization is developed for the response of the SSM/I to a set of nine atmospheric and ocean surface parameters. The brightness temperature model includes a closed-form approximation to microwave radiative transfer in a non-scattering atmosphere and fitted models for surface emission and scattering based on geometric optics calculations for the roughened sea surface. The combined model is empirically tuned using suitable sets of SSM/I data and coincident surface observations. The brightness temperature model is then used to examine the sensitivity of the SSM/I to realistic variations in the scene being observed and to evaluate the theoretical maximum precision of global SSM/I retrievals of integrated water vapor, integrated cloud liquid water, and surface wind speed. A general minimum-variance method for optimally retrieving geophysical parameters from multichannel brightness temperature measurements is outlined, and several global statistical constraints of the type required by this method are computed. Finally, a unified set of efficient statistical and semi-physical algorithms is presented for obtaining fields of surface wind speed, integrated water vapor, cloud liquid water, and precipitation from SSM/I brightness temperature data. Features include: a semi-physical method for retrieving integrated cloud liquid water at 15 km resolution and with rms errors as small as approximately 0.02 kg/sq m; a 3-channel statistical algorithm for integrated water vapor which was constructed so as to have improved linear response to water vapor and reduced sensitivity to precipitation; and two complementary indices of precipitation activity (based on 37 GHz attenuation and 85 GHz scattering, respectively), each of which are relatively

  8. Effect of the troposphere on surface neutron counter measurements

    CERN Document Server

    Aplin, K L; Bennett, A J

    2005-01-01

    Surface neutron counter data are often used as a proxy for atmospheric ionisation from cosmic rays in studies of extraterrestrial effects on climate. Neutron counter instrumentation was developed in the 1950s and relationships between neutron counts, ionisation and meteorological conditions were investigated thoroughly using the techniques available at the time; the analysis can now be extended using modern data. Whilst surface neutron counts are shown to be a good proxy for ionisation rate, the usual meteorological correction applied to surface neutron measurements, using surface atmospheric pressure, does not completely compensate for tropospheric effects on neutron data. Residual correlations remain between neutron counts, atmospheric pressure and geopotential height, obtained from meteorological reanalysis data. These correlations may be caused by variations in the height and temperature of the atmospheric layer at ~100hPa. This is where the primary cosmic rays interact with atmospheric air, producing a c...

  9. Research on 14 MeV Neutron Induced Single-event-effects in SRAMs

    Institute of Scientific and Technical Information of China (English)

    FAN; Hui; GUO; Gang; SHEN; Dong-jun; LIU; Jian-cheng

    2013-01-01

    High energy neutrons are produced in nuclear cascade showers created by nuclear spallation reactions between cosmic rays(mainly protons)and atmospheric nuclei(nitrogen and oxygen).Atmospheric neutrons have been identified as the main cause of single-event-effects(SEE)at elevated altitudes.Avionics are vulnerable to atmospheric neutrons,which can easily produce SEE in

  10. Neutron Reference Benchmark Field Specification: ACRR 44 Inch Lead-Boron (LB44) Bucket Environment (ACRR-LB44-CC-32-CL).

    Energy Technology Data Exchange (ETDEWEB)

    Vega, Richard Manuel [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Griffin, Patrick J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Vehar, David W. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-07-01

    This report was put together to support the International Atomic Energy Agency (IAEA) REAL- 2016 activity to validate the dosimetry community’s ability to use a consistent set of activation data and to derive consistent spectral characterizations. The report captures details of integral measurements taken in the Annular Core Research Reactor (ACRR) central cavity with the 44 inch Lead-Boron (LB44) bucket, reference neutron benchmark field. The field is described and an “a priori” calculated neutron spectrum is reported, based on MCNP6 calculations, and a subject matter expert (SME) based covariance matrix is given for this “a priori” spectrum. The results of 31 integral dosimetry measurements in the neutron field are reported.

  11. Long-term observations of 14C-based atmospheric fossil fuel CO2 (FFCO2) and the CO/FFCO2 ratio in the Heidelberg urban environment

    Science.gov (United States)

    Levin, Ingeborg; Hammer, Samuel; Kromer, Bernd

    2013-04-01

    Urban environments are large emitters of fossil fuel CO2 and of combustion-related pollutants, such as carbon monoxide (CO). While huge efforts are currently undertaken to agree on commitments to reduce fossil fuel CO2 emissions, these have not really been successful yet, and the global atmospheric CO2 abundance is still increasing. However, the implementation of emission controls on pollutants, e.g. from traffic, seem to have been more efficient, based on recent emission inventory data (e.g. http://www.statistik.baden-wuerttemberg.de). In order to verify this bottom-up information we present here ten years of quasi-continuous atmospheric observations of CO2, fossil fuel CO2 (FFCO2) and CO in Heidelberg. The fossil fuel CO2 component is determined from integrated radiocarbon (14CO2) measurements, exploiting the fact that fossil fuel CO2 lacks 14C (e.g. Levin et al., Geophys. Res. Lett. 30, 2003). Our measurements show that the fossil fuel CO2 level in the Heidelberg suburbs has not significantly changed (i.e. decreased) in the last decade. Observed inter-annual variations are rather due to inter-annual changes of atmospheric transport, as was already reported by Levin and Rödenbeck (Naturwissenschaften 95, 2008). However, we find a ca. 25% change in the CO/FFCO2 ratio of the regional concentration offsets compared to background levels from about 14.5 ppb/ppm in 2002 to about 11 ppb/ppm in 2009. This observation is in very good agreement with the emission statistic for the closer catchment area of our measurement site. The Statistische Landesamt, Baden-Württemberg (http://www.statistik.baden-wuerttemberg.de) reported a change in the CO to FFCO2 emission ratio for the city area of Heidelberg from 13.8 ppb/ppm in 2000 to 10.5 ppb/ppm in 2007. A more than 20% decrease of the CO/FFCO2 emission ratio is also reported for the whole state of Baden-Württemberg (south-west Germany), but note that these ratios are generally smaller, between 11.5 and 9 ppb/ppm, due to a

  12. Neutron Radiography

    Directory of Open Access Journals (Sweden)

    A. R. Reddy

    1982-07-01

    Full Text Available The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  13. Neutron And Proton Single Event Upsets At Reduced Bias

    CERN Document Server

    Savage, M W

    2000-01-01

    In the terrestrial radiation environment, neutrons generated by cosmic-ray interactions in the atmosphere and the ambient space radiation environment are the dominant species of strongly interacting particles encountered. The interaction of the terrestrial neutron radiation flux and the silicon nuclei of static random access memories (SRAMS) can result in the loss of information in the memory devices. Such soft errors are known as Single Event Upsets or SEUs. One of the key parameters is the amount of charge that must be collected by the drains for the cell to upset. This value is known as the critical charge. A novel approach to determine the critical charge is explored in regards to neutron and proton induced upsets. This approach is described in detail, allowing determination of the critical charge from a radioactive source rather than high-energy protons from an accelerator facility. In the course of these studies, one device is found that has an unexpected response to neutrons. This device is tested and ...

  14. Grey Correlation Research on Atmospheric Corrosion Environment Factors of Aircraft LY12CZ Aluminum Alloy%飞机用LY12CZ材料大气腐蚀环境因子灰色关联性研究

    Institute of Scientific and Technical Information of China (English)

    刘治国; 李旭东; 穆志韬

    2012-01-01

    The atmospheric environment causing atmospheric corrosion of aircraft I.Y12CZ structure is viewed as a grey system. The weather and medium environment factor data of typical climate territories were statistically analyzed to calculate the atmospheric corrosion rate data of aircraft LY12CZ aluminum alloy in different corrosion years. The grey correlation of environment factors was analyzed based on grey system theory with the aim to quantitatively analyze the influence degree of different environment factors on the atmospheric corrosion rate of LY12CZ. The analysis results show that the number of fog days and the CI concentration are the strongest inflence factors on the atmospheric corrosion rate of LY12CZ among all the weather and medium environment factors.%影响LY12CZ材料大气腐蚀的大气环境是灰色系统。选取典型地域的大气环境因子(气象环境和介质环境)统计数据,并利用LY12CZ材料不同腐蚀年限的大气腐蚀速率计算结果,依据灰色系统理论对影响LY12CZ材料大气腐蚀速率的环境因子灰色关联性进行计算分析,量化研究不同环境因子对LY12CZ材料大气腐蚀速率的影响程度。结果表明,雾日数和C1-浓度分别为气象环境因子和介质环境因子中对LY12CZ的大气腐蚀速率影响最大的环境因子。

  15. Atmospheric heating due to black carbon aerosol during the summer monsoon period over Ballia: A rural environment over Indo-Gangetic Plain

    Science.gov (United States)

    Tiwari, S.; Dumka, U. C.; Hopke, P. K.; Tunved, P.; Srivastava, A. K.; Bisht, D. S.; Chakrabarty, R. K.

    2016-09-01

    Black carbon (BC) aerosols are one of the most uncertain drivers of global climate change. The prevailing view is that BC mass concentrations are low in rural areas where industrialization and vehicular emissions are at a minimum. As part of a national research program called the "Ganga Basin Ground Based Experiment-2014 under the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) Phase-III" of Ministry of Earth Sciences, Government of India, the continuous measurements of BC and particulate matter (PM) mass concentrations, were conducted in a rural environment in the highly-polluted Indo-Gangetic Plain region during 16th June to 15th August (monsoon period), 2014. The mean mass concentration of BC was 4.03 (± 0.85) μg m- 3 with a daily variability between 2.4 and 5.64 μg m- 3, however, the mean mass PM concentrations [near ultrafine (PM1.0), fine (PM2.5) and inhalable (PM10)] were 29.1(± 16.2), 34.7 (± 19.9) and 43.7 (± 28.3) μg m- 3, respectively. The contribution of BC in PM1.0 was approximately 13%, which is one of the highest being recorded. Diurnally, the BC mass concentrations were highest (mean: 5.89 μg m- 3) between 20:00 to 22:00 local time (LT) due to the burning of biofuels/biomass such as wood, dung, straw and crop residue mixed with dung by the local residents for cooking purposes. The atmospheric direct radiative forcing values due to the composite and BC aerosols were determined to be + 78.3, + 44.9, and + 45.0 W m- 2 and + 42.2, + 35.4 and + 34.3 W m- 2 during the months of June, July and August, respectively. The corresponding atmospheric heating rates (AHR) for composite and BC aerosols were 2.21, 1.26 and 1.26; and 1.19, 0.99 and 0.96 K day- 1 for the month of June, July and August, respectively, with a mean of 1.57 and 1.05 K day- 1 which was 33% lower AHR (BC) than for the composite particles during the study period. This high AHR underscores the importance of absorbing aerosols such as BC contributed by

  16. Neutron spectroscopy with the Spherical Proportional Counter

    CERN Document Server

    Bougamont, E; Derre, J; Galan, J; Gerbier, G; Giomataris, I; Gros, M; Katsioulas, I; Jourde, D; Magnier, P; Navick, X F; Papaevangelou, T; Savvidis, I; Tsiledakis, G

    2015-01-01

    A novel large volume spherical proportional counter, recently developed, is used for neutron measurements. Gas mixtures of $N_{2}$ with $C_{2}H_{6}$ and pure $N_{2}$ are studied for thermal and fast neutron detection, providing a new way for the neutron spectroscopy. The neutrons are detected via the ${}^{14}N(n, p)C^{14}$ and ${}^{14}N(n, \\alpha)B^{11}$ reactions. Here we provide studies of the optimum gas mixture, the gas pressure and the most appropriate high voltage supply on the sensor of the detector in order to achieve the maximum amplification and better resolution. The detector is tested for thermal and fast neutrons detection with a ${}^{252}Cf$ and a ${}^{241}Am-{}^{9}Be$ neutron source. The atmospheric neutrons are successfully measured from thermal up to several MeV, well separated from the cosmic ray background. A comparison of the spherical proportional counter with the current available neutron counters is also given.

  17. Neutron Capture and Neutron Halos

    OpenAIRE

    A.Mengoni; Otsuka, T; Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Ishihara, M.

    1996-01-01

    The connection between the neutron halo observed in light neutron rich nuclei and the neutron radiative capture process is outlined. We show how nuclear structure information such as spectroscopic factors and external components of the radial wave function of loosely bound states can be derived from the neutron capture cross section. The link between the direct radiative capture and the Coulomb dissociation process is elucidated.

  18. Comment on "Detection and characterization of 0.5-8 MeV neutrons near Mercury: Evidence for a solar origin"

    CERN Document Server

    Share, Gerald; Tylka, Allan; Dennis, Brian; Ryan, James

    2014-01-01

    We argue that the hour-long neutron transient detected by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) Neutron Spectrometer beginning at 15:45 UT on 2011 June 4 is due to secondary neutrons from energetic protons interacting in the spacecraft. The protons were probably accelerated by a shock that passed the spacecraft about thirty minutes earlier. We reach this conclusion after a study of data from the MESSENGER neutron spectrometer, gamma-ray spectrometer, X-ray Spectrometer, and Energetic Particle Spectrometer, and from the particle spectrometers on STEREO A. Our conclusion differs markedly from that given by Lawrence et al. [2014] who claimed that there is "strong evidence" that the neutrons were produced by the interaction of ions in the solar atmosphere. We identify significant faults with the authors' arguments that led them to that conclusion.

  19. Climate change effects on environment (marine, atmospheric and terrestrial) and human perception in an Italian Region (Marche) and the nearby northern Adriatic Sea.

    Science.gov (United States)

    Appiotti, F.; Krzelj, M.; Marincioni, F.; Russo, A.

    2012-04-01

    An integrated analysis of recent climate change, including atmosphere, sea and land, as well as some of the impacts on society, has been conducted on the Marche Region in central Italy and the northern portion of the Adriatic Sea. The Marche Region is one of the 20 administrative divisions of Italy, located at a latitude approximately 43° North, with a total surface area of 9,366 km2 and 1,565,000 residents. The northern Adriatic Sea is the northernmost area of the Mediterranean Sea, and it has peculiar relevance for several aspects (environment, tourism, fisheries, economy). The collected environmental data included meteorological stations (daily maximum and minimum air temperature, daily precipitation), oceanographic stations (sea temperature, salinity, dissolved oxygen, nutrient salts concentration, chlorophyll) and river flows, over the last 50 years. The collected social data include 800 questionnaires and interviews carried out on selected samples of residents, decision-makers and emergency managers. These questionnaires and interviews aimed at highlighting the perception of climate change risks. The trend analysis of air temperature and precipitation data detailed an overall temperature increase in all seasons and rainfall decreases in Winter, Spring and Summer with Autumn increases, influencing river flow changes. Marine data showed a relevant warming of the water column in the period after 1990 in comparison with the previous period, particularly in the cold season. Surface salinity increased in Spring and Summer and strongly decreased in Autumn and Winter (according with the precipitation and river flow changes). These last mentioned changes, combined with anthropogenic effects, also influenced the marine ecosystems, with changes of nutrient salts, chlorophyll and dissolved oxygen. Changes in nutrient discharge from rivers influenced the average marine chlorophyll concentration reduction and the consequent average reduction of warm season hypoxic

  20. Electromagnetic Environment Simulation Research in Inhomogeneous Atmosphere Structure%不均匀大气结构中的电磁环境仿真研究

    Institute of Scientific and Technical Information of China (English)

    程芳; 沈怀荣

    2012-01-01

    采用三维矢量抛物方程方法建立了电磁环境仿真模型,提出了基于旋转波阵面处理不规则地表边界条件的算法,简化了边界处理过程;为了计算脉冲电波传播场,采用傅里叶变换方法用脉冲包络代替单频电波,提出了近似系数求解多规点反复计算的方法;通过Kriging算法对她形高程进行插值,分析了脉冲电波在不均匀大气结构中的传播特征;最后通过数值仿真说明了模型的正确性。%The electromagnetic environment simulation model was set up by three-dimensional vector parabolic equation method. A new method of rotating propagation plane was derived. Based on this method, the processing of boundary conditions was simplified. In order to accurately calculate the pulse wave propagation field, Fourier transform was used to produce the pulse wave packet, and an approximate coefficient method was proposed to decrease superposition times. For the regular grid elevation data, Kriging method was used to obtain the interpolation data, and pulse wave propagation loss was calculated in inhomogeneous atmosphere structure. Finally, numerical simulation results show that the model is accurate and valid.

  1. Parietaria judaica flowering phenology, pollen production, viability and atmospheric circulation, and expansive ability in the urban environment: impacts of environmental factors

    Science.gov (United States)

    Fotiou, Christina; Damialis, Athanasios; Krigas, Nikolaos; Halley, John M.; Vokou, Despoina

    2011-01-01

    Parietaria judaica (Urticaceae) grows abundantly in urban areas of the Mediterranean region. Its pollen is a major allergy source. We studied the species' distribution and abundance in and around Thessaloniki (Greece), pollen production and pollen season. We also examined how urban pollution affects pollen viability. Our ultimate goal was to obtain an estimate of the species' performance and ability to expand under different environmental conditions related to climate change. We mapped P. judaica and the other Urticaceae species. In a north- and a south-facing population, we recorded the progress of P. judaica flowering and estimated the pollen content per flower, shoot and surface unit. We concurrently assessed atmospheric circulation of Urticaceae pollen. We estimated P. judaica pollen viability and Cu, Pb and Zn concentrations in plants collected from sites differing in traffic intensity. P. judaica is the most abundant Urticaceae species in the area; its occurrence has increased dramatically over the last 100 years. Production of flowers is intense in spring and autumn. Flowering started 12 days earlier in the south-facing population in spring, and 3 days later in autumn. Pollen production was higher in spring and in the south-facing population. Flower and pollen production were positively correlated with the size of the plant and the flower, respectively. Copper and lead concentrations in plants were positively correlated with pollen viability, which was higher for plants collected from high-traffic sites. P. judaica has a high phenotypic plasticity; this is a feature that promotes success of expansive and invasive species. It is also well adapted to warm and polluted urban environments. The climatic change forecast for the Mediterranean region could provoke earlier, longer, and more pronounced flowering and, consequently, more P. judaica pollen in the air. In return, this would result in increased severity of Parietaria pollinosis.

  2. First measurements of the Martian radiation environment

    International Nuclear Information System (INIS)

    The 2001 Mars Odyssey spacecraft has been returning data from Mars since February 2002. Its orbit is polar and nearly circular, about 400 km above the surface, with a two-hour period. Among the instruments onboard Odyssey are the Martian Radiation Environment Experiment (MARIE) and the Gamma Ray Spectrometer (GRS), which is a suite of instruments that includes several neutron detectors. This paper focuses on results from MARIE, which is measuring Galactic Cosmic Rays (GCR) and Solar Particle Events (SPE) at Mars in order to assess radiation health risks to future human explorers. MARIE is highly efficient for SPE, and for GCR in the charge range from 2 (helium) to 10 (neon); spectra obtained in this range are compared to data from the ACE/ CRIS detector and show good agreement. The SPE data obtained by MARIE are unique and may show effects due to 'magnetic anomalies,' regions of remanent magnetism on the Martian surface. Data from the Mars Global Surveyor magnetometer are used in this analysis. Although the GRS instruments are primarily intended to measure radiation from the Martian surface, both the gamma-ray detector and the neutron detectors provide valuable information about the local radiation environment at Mars. The gamma-ray crystal is useful in providing coverage during MARIE data outages, which arise due to limited storage space and tend to limit acquisition during SPE. The neutron detectors provide data that can, with modeling of neutron transport through the atmosphere, be used to predict surface neutron doses. The combined data from these instruments are giving a clear picture of the radiation environment at Mars and the potential risks that will be faced by humans who venture there

  3. Neutron beam applications

    International Nuclear Information System (INIS)

    For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis has been performed. High resolution powder diffractometer, after the installation and performance test, has been opened and used actively for crystal structure analysis, magnetic structure analysis, phase transition study, etc., since January 1998. The main components for four circle diffractometer were developed and, after performance test, it has been opened for crystal structure analysis and texture measurement since the end of 1999. For the small angle neutron spectrometer, the main component development and test, beam characterization, and the preliminary experiment for the structure study of polymer have been carried out. Neutron radiography facility, after the precise performance test, has been used for the non-destructive test of industrial component. Addition to the development of main instruments, for the effective utilization of those facilities, the scattering techniques relating to quantitative phase analysis, magnetic structure analysis, texture measurement, residual stress measurement, polymer study, etc, were developed. For the neutron radiography, photographing and printing technique on direct and indirect method was stabilized and the development for the real time image processing technique by neutron TV was carried out. The sample environment facilities for low and high temperature, magnetic field were also developed

  4. Estimation and analysis of neutron skyshine at particle accelerators

    International Nuclear Information System (INIS)

    This report deals with the neutron dosimetry at the accelerator environment with a special emphasis given to the neutron skyshine problem. Theoretical studies have been carried out for the estimation of neutron skyshine dose using experimentally measured neutron spectra as well as those obtained using theoretically simulated nuclear reaction model calculations. A detailed analysis has been performed with respect to several variables. (author)

  5. Chloride ion transport in fly ash concrete under marine atmospheric environment%海洋大气中氯离子在粉煤灰混凝土中的传输规律

    Institute of Scientific and Technical Information of China (English)

    鲁彩凤; 袁迎曙; 季海霞; 姬永生

    2012-01-01

    为了实现海洋大气环境中粉煤灰混凝土耐久性使用寿命的预测,从氯离子在人工模拟海洋大气环境中粉煤灰混凝土中的传输试验出发,结合氯离子在非饱和多孔介质中的传输机理,研究海洋大气环境下混凝土内部微环境(微环境温度和相对湿度)及粉煤灰掺量对氯离子传输速率的影响程度,并与人工模拟海洋水下环境试验结果进行对比分析.研究结果表明:1)在海洋大气环境与海洋水下环境下,氯离子在粉煤灰混凝土中的扩散模型形式上一致,粉煤灰的掺人对氯离子传输能力有一定的影响,但不会改变氯离子在混凝土中的传输机理.2)当粉煤灰掺量一定时,微环境相对湿度越高(微环境温度一定),海洋大气环境氯离子扩散系数越大;但微环境温度(微环境相对湿度一定)对海洋水下环境和海洋大气环境中氯离子迁移的影响程度不同.3)粉煤灰掺量(微环境温度、相对湿度一定)对海洋水下环境和海洋大气环境氯离子扩散系数的影响规律不同.%The effect of micro-environment (temperature and relative humidity inside the concrete) and fly ash replacement on chloride ion transport in the fly ash concrete was analyzed from test results in artificial marine atmospheric zone and chloride diffusion mechanism in non-saturated porous media in order to predict durability service life. Then a comparative analysis between marine atmospheric environment and marine underwater environment was conducted. Results show that; l)the form of chloride diffusion model in fly ash concrete under atmosphere environment is consistent with that under underwater marine environment! the fly ash has a certain effect on chloride ion transport capacity, but it does not change the transport mechanism of chloride ion transport in fly ash concrete. 2) the higher the micro-environment relative humidity is (the same micro-environment temperature), the greater chloride ion

  6. Neutron sources

    International Nuclear Information System (INIS)

    As neutron scattering experiments have grown more and more demanding with respect to resolution and quality, it became more and more necessary to include the neutron source itself in the design of an experimental setup. In this sense the generic representation of a neutron scattering arrangement includes the primary neutron source and the associated spectrum shifter (or moderator). In fact, the design of a modern neutron source will start from a set of users requirements and will proceed 'inwards' through a selection of the moderators (spectrum shifters) to the primary source best suited to meet these often conflicting needs. This paper aims at explaining the options source designers have to match the neutron source performance to the users' demands. (author)

  7. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C.; Jardret; Vincent D.

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  8. Neutron dosimetry

    International Nuclear Information System (INIS)

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq 241 Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s-1 and 0,5 μSv s-1. A calibrated 50 nSv s-1 thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the 241 Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold 241 Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,α) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kVpp cm-1, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46± 0,09) 104 tracks cm-2 mSv-1 for thermal neutrons, (9±3) 102 tracks cm-2 mSV-1 for intermediate neutrons and (26±4) tracks cm-2 mSv-1 for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990's ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is sufficiently sensitive to thermal and intermediate neutrons but fast neutron monitoring ar radiological protection level

  9. Effects of chronic exposure to low-level pollutants in the environment. Prepared for the Subcommittee on the Environment and the Atmosphere of the Committee on Science and Technology, US House of Representatives, Ninety-Fourth Congress, First Session by the Congressional Research Service, Library of Congress, Serial 0

    Energy Technology Data Exchange (ETDEWEB)

    1975-01-01

    This report was prepared for the Subcommittee on the Environment and the Atmosphere of the US House of Representatives Committee on Science and Technology. It describes the effects of low-level, persistent pollutants on human health, fish and wildlife, agriculture, and climate.

  10. Physical profile data collected during the calendar year 2003 for the Tropical Atmosphere Ocean Project by NOAA's Pacific Marine Environment Lab (NODC Accession 0001364)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical profile data were collected using meteorological sensors and CTD casts in the Northeast Pacific Ocean from the NOAA Ship KA'IMIMOANA and NOAA Ship RONALD...

  11. Interpretation of the distribution of sedimentary environments of the sidescan sonar mosaic of National Oceanic and Atmospheric Administration (NOAA) survey H11043 off Branford, Connecticut

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has...

  12. Definition by modelling, optimization and characterization of a neutron spectrometry system based on Bonner spheres extended to the high-energy range

    International Nuclear Information System (INIS)

    This research thesis first describes the problematic of the effects of natural radiation on micro- and nano-electronic components, and the atmospheric-radiative stress of atmospheric neutrons from cosmic origin: issue of 'Single event upsets', present knowledge of the atmospheric radiative environment induced by cosmic rays. The author then presents the neutron-based detection and spectrometry by using the Bonner sphere technique: principle of moderating spheres, definition and mathematical formulation of neutron spectrometry using Bonner spheres, active sensors of thermal neutrons, response of a system to conventional Bonner spheres, extension to the range of high energies. Then, he reports the development of a Bonner sphere system extended to the high-energy range for the spectrometry of atmospheric neutrons: definition of a conventional system, Monte Carlo calculation of response functions, development of the response matrix, representation and semi-empirical verification of fluence response, uncertainty analysis, extension to high energies, and measurement tests of the spectrometer. He reports the use of a Monte Carlo simulation to characterize the spectrometer response in the high-energy range

  13. Micromegas neutron beam monitor neutronics.

    Science.gov (United States)

    Stephan, Andrew C; Miller, Laurence F

    2005-01-01

    The Micromegas is a type of ionising radiation detector that consists of a gas chamber sandwiched between two parallel plate electrodes, with the gas chamber divided by a Frisch grid into drift and amplification gaps. Investigators have applied it to a number of different applications, such as charged particle, X-ray and neutron detection. A Micromegas device has been tested as a neutron beam monitor at CERN and is expected to be used for that purpose at the Spallation Neutron Source (SNS) under construction in Oak Ridge, TN. For the Micromegas to function effectively as neutron beam monitor, it should cause minimal disruption to the neutron beam in question. Specifically, it should scatter as few neutrons as possible and avoid neutron absorption when it does not contribute to generating useful information concerning the neutron beam. Here, we present the results of Monte Carlo calculations of the effect of different types of wall materials and detector gases on neutron beams and suggest methods for minimising disruption to the beam. PMID:16381746

  14. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  15. Neutron gun

    International Nuclear Information System (INIS)

    The neutron gun combines a new core ion source of the cold type based on X-ray ionization and new cold type of neutron source working with core ion generation. The neutrons are formed from the impact of core ions on the negatively charged anode. Based on a new conversion function, the function of the positive anode becomes analogous to the beta-unstable decomposition of a neutron. A core ion and neutron amplifier in the sense of amplifying the number is derived from the beta-unstable neutron decomposition, in order to raise the output of a gun in pulsed operation by using the number amplification in the intervals between the pulses. The method of construction is simple and cheap, the equipment has purely linear acceleration or operation with circular acceleration with linear pre-acceleration as an alternative. Purely linear operation should be sufficient for medical applications, e.g. for neutron photography to replay X-ray photography and particularly for neutron scalpels in the surgical treatment of tumours. (orig./HP)

  16. Neutron transport

    International Nuclear Information System (INIS)

    This bibliographical note presents a reference book which addresses the study of neutron transport in matter, the study of conditions for a chain reaction and the study of modifications of matter composition due to nuclear reactions. This book presents the main nuclear data, their measurement, assessment and processing, and the spallation. It proposes an overview of methods applied for the study of neutron transport: basic equations and their derived forms, deterministic methods and Monte Carlo method of resolution of the Boltzmann equation, methods of resolution of generalized Bateman equations, methods of time resolution of space kinetics coupled equations. It presents the main calculation codes, discusses the qualification and experimental aspects, and gives an overview of neutron transport applications: neutron transport calculation of reactors, neutron transport coupled with other disciplines, physics of fuel cycle, criticality

  17. Neutron tubes

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui; Reijonen, Jani

    2008-03-11

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  18. Neutron gamma fraction imaging: Detection, location and identification of neutron sources

    International Nuclear Information System (INIS)

    In this paper imaging of neutron sources and identification and separation of a neutron source from another neutron source is described. The system is based upon organic liquid scintillator detector, tungsten collimator, bespoke fast digitiser and adjustable equatorial mount. Three environments have been investigated with this setup corresponding to an AmBe neutron source, a 252Cf neutron source and both sources together separated in space. In each case, events are detected, digitised, discriminated and radiation images plotted corresponding to the area investigated. The visualised neutron count distributions clearly locate the neutron source and, relative gamma to neutron (or neutron to gamma) fraction images aid in discriminating AmBe sources from 252Cf source. The measurements were performed in the low scatter facility of the National Physical Laboratory, Teddington, UK

  19. A comparative study of history-based versus vectorized Monte Carlo methods in the GPU/CUDA environment for a simple neutron eigenvalue problem

    International Nuclear Information System (INIS)

    For nuclear reactor analysis such as the neutron eigenvalue calculations, the time consuming Monte Carlo (MC) simulations can be accelerated by using graphics processing units (GPUs). However, traditional MC methods are often history-based, and their performance on GPUs is affected significantly by the thread divergence problem. In this paper we describe the development of a newly designed event-based vectorized MC algorithm for solving the neutron eigenvalue problem. The code was implemented using NVIDIA's Compute Unified Device Architecture (CUDA), and tested on a NVIDIA Tesla M2090 GPU card. We found that although the vectorized MC algorithm greatly reduces the occurrence of thread divergence thus enhancing the warp execution efficiency, the overall simulation speed is roughly ten times slower than the history-based MC code on GPUs. Profiling results suggest that the slow speed is probably due to the memory access latency caused by the large amount of global memory transactions. Possible solutions to improve the code efficiency are discussed. (authors)

  20. 2010 Neutron Review: ORNL Neutron Sciences Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Bardoel, Agatha A [ORNL; Counce, Deborah M [ORNL; Ekkebus, Allen E [ORNL; Horak, Charlie M [ORNL; Nagler, Stephen E [ORNL; Kszos, Lynn A [ORNL

    2011-06-01

    During 2010, the Neutron Sciences Directorate focused on producing world-class science, while supporting the needs of the scientific community. As the instrument, sample environment, and data analysis tools at High Flux Isotope Reactor (HFIR ) and Spallation Neutron Source (SNS) have grown over the last year, so has promising neutron scattering research. This was an exciting year in science, technology, and operations. Some topics discussed are: (1) HFIR and SNS Experiments Take Gordon Battelle Awards for Scientific Discovery - Battelle Memorial Institute presented the inaugural Gordon Battelle Prizes for scientific discovery and technology impact in 2010. Battelle awards the prizes to recognize the most significant advancements at national laboratories that it manages or co-manages. (2) Discovery of Element 117 - As part of an international team of scientists from Russia and the United States, HFIR staff played a pivotal role in the discovery by generating the berkelium used to produce the new element. A total of six atoms of ''ununseptium'' were detected in a two-year campaign employing HFIR and the Radiochemical Engineering Development Center at Oak Ridge National Laboratory (ORNL) and the heavy-ion accelerator capabilities at the Joint Institute for Nuclear Research in Dubna, Russia. The discovery of the new element expands the understanding of the properties of nuclei at extreme numbers of protons and neutrons. The production of a new element and observation of 11 new heaviest isotopes demonstrate the increased stability of super-heavy elements with increasing neutron numbers and provide the strongest evidence to date for the existence of an island of enhanced stability for super-heavy elements. (3) Studies of Iron-Based High-Temperature Superconductors - ORNL applied its distinctive capabilities in neutron scattering, chemistry, physics, and computation to detailed studies of the magnetic excitations of iron-based superconductors (iron

  1. 2010 Neutron Review: ORNL Neutron Sciences Progress Report

    International Nuclear Information System (INIS)

    During 2010, the Neutron Sciences Directorate focused on producing world-class science, while supporting the needs of the scientific community. As the instrument, sample environment, and data analysis tools at High Flux Isotope Reactor (HFIR ) and Spallation Neutron Source (SNS) have grown over the last year, so has promising neutron scattering research. This was an exciting year in science, technology, and operations. Some topics discussed are: (1) HFIR and SNS Experiments Take Gordon Battelle Awards for Scientific Discovery - Battelle Memorial Institute presented the inaugural Gordon Battelle Prizes for scientific discovery and technology impact in 2010. Battelle awards the prizes to recognize the most significant advancements at national laboratories that it manages or co-manages. (2) Discovery of Element 117 - As part of an international team of scientists from Russia and the United States, HFIR staff played a pivotal role in the discovery by generating the berkelium used to produce the new element. A total of six atoms of ''ununseptium'' were detected in a two-year campaign employing HFIR and the Radiochemical Engineering Development Center at Oak Ridge National Laboratory (ORNL) and the heavy-ion accelerator capabilities at the Joint Institute for Nuclear Research in Dubna, Russia. The discovery of the new element expands the understanding of the properties of nuclei at extreme numbers of protons and neutrons. The production of a new element and observation of 11 new heaviest isotopes demonstrate the increased stability of super-heavy elements with increasing neutron numbers and provide the strongest evidence to date for the existence of an island of enhanced stability for super-heavy elements. (3) Studies of Iron-Based High-Temperature Superconductors - ORNL applied its distinctive capabilities in neutron scattering, chemistry, physics, and computation to detailed studies of the magnetic excitations of iron-based superconductors (iron pnictides and

  2. Martian Radiation Environment Experiment (MARIE)

    Science.gov (United States)

    Badhwar, Gautam D.

    1999-01-01

    Space radiation presents a very serious hazard to crews of interplanetary human missions. The two sources of this radiation are the galactic cosmic rays (GCR) and solar energetic particle (SEP) events. The GCR provides a steady source of low dose rate radiation that is primarily responsible for stochastic effects, such as cancer, and can effect the response of the central nervous system. Nuclear interactions of these components with the Martian atmosphere produces substantial flux of neutrons with high Radio Biological Effectiveness. The uncertainty in the knowledge of many fragmentation cross sections and their energy dependence required by radiation transport codes, uncertainties in the ambient radiation environment, and knowledge of the Martian atmosphere, lead to large enough uncertainties in the knowledge of calculated radiation dose in both free space (cruise phase), in Martian orbit, and on Martian surface. Direct measurements of radiation levels, the relative contributions of protons, neutrons, and heavy ions, and Martian atmospheric characteristics is thus a prerequisite for any human mission. An integrated suite of two spectrometers to provide these data will be described. The Orbiter spectrometer will measure the energy spectrum of SEP events from 15 to 500 MeV/n, and when combined with data from other space based instruments, such as the Advanced Composition Explorer (ACE), would provide accurate GCR spectra also. The Lander spectrometer would measure the absorbed dose rate, dose equivalent dose rate, and the linear energy transfer (LET) spectra and is capable of separating the relative contribution of these quantities from protons, neutrons, and high Z particles. There are two separate flight instruments, one for the Orbiter and one for the Lander, based on a common design of the backplane, the central processing unit (CPU), power supply, and onboard data storage. The Orbiter instrument consists of an energetic particle spectrometer that can measure

  3. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful......, in order to encompass dynamic atmospheres as intertwined, constantly shifting negotiations between the rhythms of the environment and of the body. The contribution of this paper is to unravel these negotiations of diverse rhythms, in order to approach dynamic atmospheres from an operational...

  4. Modification of spacecraft charging and the near-plasma environment caused by the interaction of an artificial electron beam with the earth's upper atmosphere

    DEFF Research Database (Denmark)

    Neubert, Torsten; Banks, P. M.; Gilchrist, B.E.; Fraser-Smith, A.C.; Wiliamson, P.R.; Raitt, W.J.; Myers, N.B.; Sasaki, S.

    1991-01-01

    The Beam-Atmosphere Interaction (BAI) involves the ionization created in the earth's upper atmosphere by electron beams emitted from a low altitude spacecraft. This process is described by two coupled non-linear differential electron transport equations for the up-going (along magnetic field line......) and down-going differential energy flux. The equations are solved numerically,using the MSIS atmospheric model and the IRI ionospheric model, yielding estimates of the differential electron energy flux density at the spacecraft location. At altitudes below 200-250 km and forbeam energies around 1 ke......V, it is shown that secondary electrons supply a significant contribution to the return current to the spacecraft and thereby reduce the spacecraft potential. Our numerical results are in good agreement with observations from the CHARGE-2 sounding rocket experiment.A more detailed study of the BAI as it...

  5. Neutron radiography

    International Nuclear Information System (INIS)

    This introduction is addressed to an audience active in diverse forms of neutron source applications but not directly familiar with neutron radiography. Neutron radiography is, of course, similar to, and complementary to, radiography using x-rays. However, neutrons, being sensitive to the nuclear properties of materials, provide information fundamentally different from x-rays. For example, neutrons can penetrate many dense metals such as uranium, lead, bismuth or steel, and can reveal details of internal hydrogenous components: explosives, lubricants and gaskets. For nuclear fuel inspection neutron radiography offers the ability to penetrate dense uranium-238 and contrast the isotopes U-235 or Pu-239 and also offers the ability to discriminate against unwanted interference from gamma radiation. In addition to advantages in industrial applications, there are special situations in fields such as medical diagnostics, dentistry, agriculture and forensic science. Comprehensive accounts of applications in the field can be found in the proceedings of the world conferences on neutron radiography: USA (1981), FRANCE (1986). A third conference in this series is scheduled for May 1989 in Japan

  6. Effect of the troposphere on surface neutron counter measurements

    OpenAIRE

    Aplin, K. L.; Harrison, R. G.; Bennett, A.J.

    2005-01-01

    Surface neutron counter data are often used as a proxy for atmospheric ionisation from cosmic rays in studies of extraterrestrial effects on climate. Neutron counter instrumentation was developed in the 1950s and relationships between neutron counts, ionisation and meteorological conditions were investigated thoroughly using the techniques available at the time; the analysis can now be extended using modern data. Whilst surface neutron counts are shown to be a good proxy for ionisation rate, ...

  7. Transport of solar protons through the atmosphere during GLE

    International Nuclear Information System (INIS)

    Using the PLANETOCOSMICS simulation framework we simulated solar proton transport through the Earth's atmosphere and estimated angular and energy distributions of secondaries (protons, electrons, positrons, muons, photons and neutrons) at various atmospheric levels. As the source spectrum of solar protons at the boundary of atmosphere the spectra obtained with the GLE modeling from the data of neutron monitor network in a number of events have been used. These Monte Carlo simulation results were compared with the available solar cosmic ray neutron monitor and balloon measurements. The calculated solar proton spectra are in good agreement with the balloon and neutron monitor observational data.

  8. Neutron radiography

    International Nuclear Information System (INIS)

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H2O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  9. Neutron anatomy

    International Nuclear Information System (INIS)

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone

  10. Neutron anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, G.E. [Univ. of Sheffield (United Kingdom)

    1994-12-31

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone.

  11. Neutron-induced soft errors in CMOS circuits

    International Nuclear Information System (INIS)

    The subject of this thesis is a systematic study of soft errors occurring in CMOS integrated circuits when being exposed to radiation. The vast majority of commercial circuits operate in the natural environment ranging from the sea level to aircraft flight altitudes (less than 20 km), where the errors are caused mainly by interaction of atmospheric neutrons with silicon. Initially, the soft error rate (SER) of a static memory was measured for supply voltages from 2V to 5V when irradiated by 14 MeV and 100 MeV neutrons. Increased error rate due to the decreased supply voltage has been identified as a potential hazard for operation of future low-voltage circuits. A novel methodology was proposed for accurate SER characterization of a manufacturing process and it was validated by measurements on a 0.6 μm process and 100 MeV neutrons. The methodology can be applied to the prediction of SER in the natural environment

  12. Neutron tomography

    International Nuclear Information System (INIS)

    In this paper a survey is given of recent developments in selected areas of neutron tomography, within the context of several applications Argonne is involved in, including high penetration of reactor-fuel bundles in thick containers (involving TREAT and NRAD facilities), dual-energy hydrogen imaging (performed at IPNS), dynamic coarse-resolution emission tomography of rector fuel under test (a proposed modification to the TREAT hodoscope), and an associated-particle system that uses neutron flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays

  13. 输变电设施周边大气的环境检测与腐蚀原因分析%Detection and Analysis of Atmospheric Corrosion Environment Around Substation

    Institute of Scientific and Technical Information of China (English)

    王平; 孙心利; 马东伟

    2015-01-01

    This paper analyzed the characteristics of atmospheric corrosion and the sources of pollutants and it was concluded that atmospheric environment detection was an important part in substation equipment corrosion analysis. Through detection and analysis of atmospheric environment around substation, the substation metal material corrosion was mainly due to the high gas composition of H2S, NH3 generated by the production sites around substation, such as sewage, chemical plants, chicken farms. This paper also proposed the prevention and treatment measures, such as strengthening environmental detection, conducting environmental assessment, etc.%以某地区为例,开展了大气环境和污染物情况的分析调查.在选择了遭受大气环境腐蚀较为严重的5个站点进行了输变电设施周围典型大气环境检测.分析认为:输变电设施铜、铁、锌等材料特性是产生腐蚀的根本因子;大气环境中的SO2、H2S和NH3是造成输变电设施腐蚀的主要因子;温度、湿度、气压和氧含量等气候条件是促进输变电设施腐蚀加剧的促进因子.

  14. Neutron scattering

    International Nuclear Information System (INIS)

    This report contains the text of 16 lectures given at the Summer School and the report on a panel discussion entitled ''the relative merits and complementarities of x-rays, synchrotron radiation, steady- and pulsed neutron sources''. figs., tabs., refs

  15. Piezonuclear Neutrons

    CERN Document Server

    Cardone, Fabio; Petrucci, Andrea

    2008-01-01

    We report the results of neutron measurements carried out during the application of ultrasounds to a solution containing only stable elements like Iron and Chlorine, without any other radioactive source of any kind. These measurements, carried out by CR39 detectors and a Boron TriFouride electronic detector, evidenced the emission of neutron pulses. These pulses stand well above the electronic noise and the background of the laboratory where the measurements were carried out.

  16. FOREWORD: Neutron metrology Neutron metrology

    Science.gov (United States)

    Thomas, David J.; Nolte, Ralf; Gressier, Vincent

    2011-12-01

    The International Committee for Weights and Measures (CIPM) has consultative committees covering various areas of metrology. The Consultative Committee for Ionizing Radiation (CCRI) differs from the others in having three sections: Section (I) deals with radiation dosimetry, Section (II) with radionuclide metrology and Section (III) with neutron metrology. In 2003 a proposal was made to publish special issues of Metrologia covering the work of the three Sections. Section (II) was the first to complete their task, and their special issue was published in 2007, volume 44(4). This was followed in 2009 by the special issue on radiation dosimetry, volume 46(2). The present issue, volume 48(6), completes the trilogy and attempts to explain neutron metrology, the youngest of the three disciplines, the neutron only having been discovered in 1932, to a wider audience and to highlight the relevance and importance of this field. When originally approached with the idea of this special issue, Section (III) immediately saw the value of a publication specifically on neutron metrology. It is a topic area where papers tend to be scattered throughout the literature in journals covering, for example, nuclear instrumentation, radiation protection or radiation measurements in general. Review articles tend to be few. People new to the field often ask for an introduction to the various topics. There are some excellent older textbooks, but these are now becoming obsolete. More experienced workers in specific areas of neutron metrology can find it difficult to know the latest position in related areas. The papers in this issue attempt, without presenting a purely historical outline, to describe the field in a sufficiently logical way to provide the novice with a clear introduction, while being sufficiently up-to-date to provide the more experienced reader with the latest scientific developments in the different topic areas. Neutron radiation fields obviously occur throughout the nuclear

  17. Contributions of the CEA-Valduc Centre control to the understanding of the transfers of atmospheric tritiated water into the different parts of the environment

    International Nuclear Information System (INIS)

    After a description of the geological environment of the Valduc Centre dedicated to tritium purification and tritiated waste processing and storage, this document presents the assessment of quantities of tritiated water released by the Valduc Centre and of their evolution in the hydro-geological environment. It provides in situ macroscopically observed data on the transfer mechanisms of water into the different parts of the environment and into the food chain by means. This is made possible by the exceptional traceability of tritiated water. Finally, a comparison between computational models and experimental measurements is given

  18. Neutron albedo effects of underground nuclear explosion

    International Nuclear Information System (INIS)

    The neutron field distribution is affected by the surrounding medium in the underground nuclear explosion. It will influence the radiation chemical diagnosis. By Monte Carlo simulation, the fuel burnup induced by device and neutron albedo was calculated. The analysis method of albedo effect on radiation chemical diagnosis result under special environment was proposed. Neutron albedo should be considered when capture reaction burnup fraction is used, and then correct analysis can be carried out on the nuclear device.The neutron field distribution is affected by the surrounding medium in the underground nuclear explosion. It will influence the radiation chemical diagnosis. By Monte Carlo simulation, the fuel burnup induced by device and neutron albedo was calculated. The analysis method of albedo effect on radiation chemical diagnosis result under special environment was proposed. Neutron albedo should be considered when capture reaction burnup fraction is used, and then correct analysis can be carried out on the nuclear device. (authors)

  19. The response of the SSM/I to the marine environment. I - An analytic model for the atmospheric component of observed brightness temperatures

    Science.gov (United States)

    Petty, Grant W.; Katsaros, Kristina B.

    1992-01-01

    A detailed parameterization is developed for the contribution of the nonprecipitating atmosphere to the microwave brightness temperatures observed by the Special Sensor Microwave/Imager (SSM/I). The atmospheric variables considered include the viewing angle, the integrated water vapor amount and scale height, the effective tropospheric lapse rate and near-surface temperature, the total cloud liquid water, the effective cloud height, and the surface pressure. The dependence of the radiative variables on meteorological variables is determined for each of the SSM/I frequencies 19.35, 22.235, 37.0, and 85.5 GHz, based on the values computed from 16,893 maritime temperature and humidity profiles representing all latitude belts and all seasons. A comparison of the predicted brightness temperatures with brightness temperatures obtained by direct numerical integration of the radiative transfer equation for the radiosonde-profile dataset yielded rms differences well below 1 K for all four SSM/I frequencies.

  20. Signature of protein adaptation to warm deep sea environments: the case of Initiation Factor 6 studied by molecular simulation and neutron scattering

    International Nuclear Information System (INIS)

    The protein Initiation Factor 6 (IF6) takes part in the protein synthesis regulation of several organisms. It was also found in archeaebacteria such as Methanococcus jannaschii which lives in deep-seas near hydrothermal vents where temperature reaches 80 C and pressure is between 250 bar and 500 bar. The aim of this work was to study for the first time dynamical and structural properties of IF6 produced by M. jannaschii and comparing them with those of the IF6 homologue present in Saccharomyces cerevisiae which lives at 'normal' environmental conditions (27 C and 1 bar). Molecular simulation gave here new insights into the adaptation of these two proteins to their respective physiological conditions and showed that the latter induced similar dynamical and structural properties: in their respective 'natural' conditions, IF6s show very similar structural fluctuations and the characteristic relaxation times which define their dynamical properties shows similar changes when comparing unfavorable conditions to physiological ones. The creation of these corresponding states between the two homologues has been interpreted by the fractional Brownian dynamics model and by a novel method for the characterization of protein secondary structures. The latter is presented here in detail together with some examples of other applications. Experimental data obtained from quasi-elastic neutron scattering seemed to support the results obtained by molecular simulations. (author)

  1. Study of the distribution characteristics of rare earth elements in Solanum lycocarpum from different tropical environments in Brazil by neutron activation analysis

    International Nuclear Information System (INIS)

    In this work, the concentration of eight rare earth elements (REE), La, Ce, Nd, Sm, Eu, Tb, Yb and Lu, was determined by neutron activation analysis (INAA), in plant leaves of Solanum lycocarpum. This species is a typical Brazilian 'cerrado' plant, widely distributed in Brazil. The analysis of the plant reference materials CRM Pine Needles (NIST 1575) and Spruce Needles (BCR 101) proved that the methodology applied was sufficiently accurate and precise for the determination of REE in plants. In order to better evaluate the uptake of the REE from the soil to the plant, the host soil was also analyzed by ESiAA. The studied areas were Salitre, MG, Serra do Cipo, MG, Lagoa da Pampulha and Mangabeiras, in Belo Horizonte, MG, and Cerrado de Emas, in Pirassununga, SP. The results were analyzed through the calculation of transfer factors soil-plant and by using diagrams normalized to chondrites. The data obtained showed different transfer factors from soil to plant as the subtract changes. Similar distribution patterns for the soil and the plant were obtained in all the studied sites, presenting an enrichment of the light REE (La to Sm), in contrast to the heavy REE (Eu to Lu), less absorbed. These results indicate that the light REE remain available to the plant in the more superficial soil layers. The similarity between the distribution patterns indicates a typical REE absorption by this species, in spite of the significant differences in the substratum . (author)

  2. Characteristic atmosphere-ocean-solid earth interactions in the Antarctic coastal and marine environment inferred from seismic and infrasound recording at Syowa Station, East Antarctica

    OpenAIRE

    Kanao, Masaki; Maggi, Alessia; Ishihara, Yoshiaki; Stutzmann, Eléonore; Yamamoto, Masa-Yuki; Toyokuni, Genti

    2013-01-01

    Several characteristic waves detected by seismographs in Antarctic stations have been recognized as originating from the physical interaction between the solid earth and the atmosphere-ocean-cryosphere system surrounding the Antarctic and may be used as a proxy for characterizing ocean wave climate. A Chaparral-type infrasound sensor was installed at Syowa Station (SYO; 39.6E, 69.0S), East Antarctica, in April 2008 during the International Polar Year (IPY2007-2008). Matching data are also ava...

  3. Thermal evolution of the crystal structure of proton conducting BaCe0.8Y0.2O3-δ from high-resolution neutron diffraction in dry and humid atmosphere.

    Science.gov (United States)

    Eriksson Andersson, Annika K; Selbach, Sverre M; Grande, Tor; Knee, Christopher S

    2015-06-21

    The crystal structure of the proton conducting perovskite BaCe(0.8)Y(0.2)O(3-δ) (BCY20) has been studied via high-resolution in situ neutron diffraction performed in controlled dry and humid (heavy water) oxygen flow. Two phase transitions, cubic Pm3[combining macron]m→R3[combining macron]c (775 °C)→Imma (250 °C) were observed on cooling from 1000 °C in dry O(2). A significant shift of the phase stability fields was observed on cooling in wet oxygen (pD(2)O ≈ 0.2 atm) with the R3[combining macron]c structure stabilised at 900 °C, and the R3[combining macron]c→Imma transition occurring at 675 °C. On cooling below 400 °C a monoclinic, I2/m, phase started to appear. The structural dependence on hydration level is primarily due to the de-stabilisation of the correlated, octahedra tilts as a consequence of structural relaxation around the oxygen vacancies present in the non-hydrated phase. The tendency of hydrated BaCe(0.8)Y(0.2)O(3-δ) to show octahedral tilting is also found to be enhanced, indicating that the deuteronic (protonic) defects influence the crystal structure, possibly via hydrogen bonding. Stabilisation of the monoclinic I2/m phase is attributed to the structural effect of deuterons that is inferred to increase on cooling as deuterons localise to a greater extent. Changing from wet oxidising (O(2) + D2O(g)) to wet reducing (5% H2 in Ar + D2O(g)) atmosphere did not influence the structure or the phase stability, indicating that Ce(4+) was not reduced under the present conditions. Based on the observed cell volume expansion protonic defects are present in the material at 900 °C at a D(2)O partial pressure of ∼0.2 atm. The origin of the chemical expansion is explained by the effective size of the oxygen vacancy being significantly smaller than the [OD] defect. Rietveld analysis has been used to locate possible sites for the deuterons in the high temperature, R3[combining macron]c and Imma, phases that are most relevant for proton transport

  4. Aerial Neutron Detection: Neutron Signatures for Nonproliferation and Emergency Response Applications

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Richard J.; Stampahar, Thomas G.; Smith, Ethan X.; Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Rourke, Timothy J.; LeDonne, Jeffrey P.; Avaro, Emanuele; Butler, D. Andre; Borders, Kevin L.; Stampahar, Jezabel; Schuck, William H.; Selfridge, Thomas L.; McKissack, Thomas M.; Duncan, William W.; Hendricks, Thane J.

    2012-10-17

    From 2007 to the present, the Remote Sensing Laboratory has been conducting a series of studies designed to expand our fundamental understanding of aerial neutron detection with the goal of designing an enhanced sensitivity detection system for long range neutron detection. Over 35 hours of aerial measurements in a helicopter were conducted for a variety of neutron emitters such as neutron point sources, a commercial nuclear power reactor, nuclear reactor spent fuel in dry cask storage, depleted uranium hexafluoride and depleted uranium metal. The goals of the project were to increase the detection sensitivity of our instruments such that a 5.4 × 104 neutron/second source could be detected at 100 feet above ground level at a speed of 70 knots and to enhance the long-range detection sensitivity for larger neutron sources, i.e., detection ranges above 1000 feet. In order to increase the sensitivity of aerial neutron detection instruments, it is important to understand the dynamics of the neutron background as a function of altitude. For aerial neutron detection, studies have shown that the neutron background primarily originates from above the aircraft, being produced in the upper atmosphere by galactic cosmic-ray interactions with air molecules. These interactions produce energetic neutrons and charged particles that cascade to the earth’s surface, producing additional neutrons in secondary collisions. Hence, the neutron background increases as a function of altitude which is an impediment to long-range neutron detection. In order to increase the sensitivity for long range detection, it is necessary to maintain a low neutron background as a function of altitude. Initial investigations show the variation in the neutron background can be decreased with the application of a cosmic-ray shield. The results of the studies along with a representative data set are presented.

  5. Neutron guides and scientific neutron equipment at CILAS/GMI

    International Nuclear Information System (INIS)

    The French company CILAS is the world's leading supplier of complete neutron guide systems. The neutron optics with multilayer coatings produced by CILAS has become an international standard for neutron beam transportation at modern research institutes. During the last 30 years, CILAS designed, produced and installed more than 5000 meters of guides in many European, American and Asian countries. By these projects the company has acquired a very strong experience with: conception, design, manufacturing, setting up of Neutron Guides. In most cases, CILAS was in charge of the design, as well as the manufacturing of the whole system, comprising optical and mechanical components, vacuum system, shutter and shielding definition. By our long experience we have also acquired good knowledge of the materials used in this specific nuclear environment and their behavior under radiation such as glass, borated or not, coatings, glue or metal. To reinforce its leadership and presence in neutron research, CILAS acquired the company Grenoble Modular Instruments (GMI) a leading company in high precision mechanics, engineering and manufacturing of spectrometers and scientific equipment for neutron and synchrotron research. This merger allows us to design and to supply a complete range of high precision optical and mechanical eqipment for neutron research. CILAS and GMI have designed, manufactured and installed a High Resolution Powder Diffractometer for the 30MW Korean Hanaro Reactor. This project included the calculation, design and supply of the complete biological shielding of the instrument as well as for the primary beam shutter on the thermal beamport. (author)

  6. German neutron scattering conference. Programme and abstracts

    International Nuclear Information System (INIS)

    The German Neutron Scattering Conference 2012 - Deutsche Neutronenstreutagung DN 2012 offers a forum for the presentation and critical discussion of recent results obtained with neutron scattering and complementary techniques. The meeting is organized on behalf of the German Committee for Research with Neutrons - Komitee Forschung mit Neutronen KFN - by the Juelich Centre for Neutron Science JCNS of Forschungszentrum Juelich GmbH. In between the large European and international neutron scattering conferences ECNS (2011 in Prague) and ICNS (2013 in Edinburgh), it offers the vibrant German and international neutron community an opportunity to debate topical issues in a stimulating atmosphere. Originating from ''BMBF Verbundtreffen'' - meetings for projects funded by the German Federal Ministry of Education and Research - this conference series has a strong tradition of providing a forum for the discussion of collaborative research projects and future developments in the field of research with neutrons in general. Neutron scattering, by its very nature, is used as a powerful probe in many different disciplines and areas, from particle and condensed matter physics through to chemistry, biology, materials sciences, engineering sciences, right up to geology and cultural heritage; the German Neutron Scattering Conference thus provides a unique chance for exploring interdisciplinary research opportunities. It also serves as a showcase for recent method and instrument developments and to inform users of new advances at neutron facilities.

  7. German neutron scattering conference. Programme and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas (ed.)

    2012-07-01

    The German Neutron Scattering Conference 2012 - Deutsche Neutronenstreutagung DN 2012 offers a forum for the presentation and critical discussion of recent results obtained with neutron scattering and complementary techniques. The meeting is organized on behalf of the German Committee for Research with Neutrons - Komitee Forschung mit Neutronen KFN - by the Juelich Centre for Neutron Science JCNS of Forschungszentrum Juelich GmbH. In between the large European and international neutron scattering conferences ECNS (2011 in Prague) and ICNS (2013 in Edinburgh), it offers the vibrant German and international neutron community an opportunity to debate topical issues in a stimulating atmosphere. Originating from ''BMBF Verbundtreffen'' - meetings for projects funded by the German Federal Ministry of Education and Research - this conference series has a strong tradition of providing a forum for the discussion of collaborative research projects and future developments in the field of research with neutrons in general. Neutron scattering, by its very nature, is used as a powerful probe in many different disciplines and areas, from particle and condensed matter physics through to chemistry, biology, materials sciences, engineering sciences, right up to geology and cultural heritage; the German Neutron Scattering Conference thus provides a unique chance for exploring interdisciplinary research opportunities. It also serves as a showcase for recent method and instrument developments and to inform users of new advances at neutron facilities.

  8. Neutron Repulsion

    CERN Document Server

    Manuel, Oliver K

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding...

  9. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...... of continental growth and volcanic outgassing, as well as biogeochemical processing of elements within the oceans. The author will seek to explore constraints on the history of oxygenation and understand which processes have regulated oxygen through this eon....

  10. neutron radiography

    International Nuclear Information System (INIS)

    Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

  11. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Heger, G. [Rheinisch-Westfaelische Technische Hochschule Aachen, Inst. fuer Kristallographie, Aachen (Germany)

    1996-12-31

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs.

  12. Effect of Aluminum and Silicon on Atmospheric Corrosion of Low-alloying Steel under Containing NaHSO3 Wet/dry Environment

    International Nuclear Information System (INIS)

    The atmospheric corrosion performance of Al-alloying Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at 30 .deg. C and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% NaHSO3 (pH∼4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage: and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of Fe3O4 and α-FeOOH. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as FeAl2O4, (Fe, Si)2(Fe, Al)O4). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere

  13. Effect of Aluminum and Silicon on Atmospheric Corrosion of Low-alloying Steel under Containing NaHSO{sub 3} Wet/dry Environment

    Energy Technology Data Exchange (ETDEWEB)

    Xinhua, Chen; Junhua, Dong; Enhou, Han; Wei, Ke [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China)

    2008-12-15

    The atmospheric corrosion performance of Al-alloying Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at 30 .deg. C and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% NaHSO{sub 3} (pH{approx}4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage: and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of Fe{sub 3}O{sub 4} and {alpha}-FeOOH. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as FeAl{sub 2}O{sub 4}, (Fe, Si){sub 2}(Fe, Al)O{sub 4}). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere.

  14. Atmospheric corrosion of low carbon steel in a polar marine environment. Study of the effect of wind regime; Corrosion atmosferica del acero bajo en carbono en un ambiente marino polar. Estudio del efecto del regimen de vientos

    Energy Technology Data Exchange (ETDEWEB)

    Rivero, S.; Chico, B.; Fuente, D. de la; Morcillo, M.

    2007-07-01

    The present work studies the atmospheric corrosion of carbon steel (UNE-EN 10130) in a sub-polar marine environment (Artigas Antarctic Scientific Base (BCAA), Uruguay) as a function of site atmospheric salinity and exposure time. A linear relationship is established between corrosion rate and airborne salinity deposition rate, valid in the deposition range encountered (125-225 mg Cl-l/m{sup 2}.d) and a bi logarithmic relationship established between corrosion and exposure time (1-4 years). Atmospheric salinity is related with the monthly wind speed average, based on the concept of the wind run. chloride ion deposition rates of less than 300 mg Cl-l/m{sup 2}.d are related with remote (oceanic) winds and coastal winds basically of speeds between 1-40 km/h, while higher deposition rates (300-700 mg Cl-/m{sup 2}.d) correspond to coastal marine winds of a certain persistence with speeds of between 41-80 km/h. (Author) 39 refs.

  15. Contribution to the development of numerical tools for the hardening of electronic devices to the neutronic and electromagnetic environment induced by a high power gain shot

    International Nuclear Information System (INIS)

    When fusion ignition will be attained inside the target chambers of high energy laser facilities (LMJ-France and NIF-Usa), a harsh environment, composed of nuclear particles and an electromagnetic pulse (EMP) will be induced. All electronic devices located in the vicinity will be sensitive to this environment. In the first part of this work, a simulation method has been developed to evaluate transient currents that will be induced in coaxial cables. The relevance of this model is then discussed thanks to comparisons with experimental results. In a second part, the possibility to simulate the propagation of the EMP, inside and outside such a big structure as a target chamber, using the finite difference in time and domain (FDTD) method is evaluated. The use of a classic FDTD method is impossible for this kind of simulation because of the huge computer resources needed. It is the reason why a 3-dimensional space-time sub-grid method for FDTD has been developed and some massively parallel FDTD calculations have also been performed. (author)

  16. Characteristics and Influencing Factors of Atmospheric Corrosion of Aluminum in Marine and Coastal Environments%海洋和沿海环境铝大气腐蚀特征及影响因素

    Institute of Scientific and Technical Information of China (English)

    胡晓黎; 韩方运; 牛林; 周少玲; 钱兆红; 赵萌; 陈佳川

    2011-01-01

    Atmospheric environments in marine and coastal regions have the characteristics of high humidity, high salinity and strong corrosivity. The research progresses in the atmospheric corrosion of widely used aluminum and its alloys in marine and coastal environments are reviewed. The corrosion characteristics, mechanisms and environmental factors which affecting the corrosion process are investigated to provide valuable references for modeling the life prediction of materials and taking effective measures for corrosion protection.%海洋和沿海大气环境具有高湿度、高盐度以及腐蚀性强的特点。本文综述了具有广泛应用的铝及铝合金在海洋和沿海环境中大气腐蚀的国内外研究动态和进展,探讨了该腐蚀体系的特征、机理及环境(气象、气候)影响因素,旨在为材料的寿命预测模型化和采取有效的腐蚀防护措施提供有价值的参考。

  17. Neutron reflectometer

    International Nuclear Information System (INIS)

    The neutron reflectometer is the most powerful and nondestructive tool to analyze the surface and buried interfaces in the layered films. Such films often have a close relation to the functional devices. Structural information in the vicinity of the interfaces is a key parameter in the field of the nanoscale science. (author)

  18. Neutron radiography

    International Nuclear Information System (INIS)

    Principles of the method, complementarity with X or gamma rays, neutron energy, detection and applications on irradiated materials and for the industrial quality control are exposed. Examples of applications in pyrotechnics, plastics, fuels, lubricants, metallurgy are given. Techniques developed by the CEA for its own needs or for industry and description of facilities in the nuclear centers are reviewed

  19. Prompt γ-ray activation analysis of Martian analogues at the FRM II neutron reactor and the verification of a Monte Carlo planetary radiation environment model

    International Nuclear Information System (INIS)

    Planetary radiation environment modelling is important to assess the habitability of a planetary body. It is also useful when interpreting the γ-ray data produced by natural emissions from radioisotopes or prompt γ-ray activation analysis. γ-ray spectra acquired in orbit or in-situ by a suitable detector can be converted into meaningful estimates of the concentration of certain elements on the surface of a planet. This paper describes the verification of a Monte Carlo model developed using the MCNPX code at University of Leicester. The model predicts the performance of a geophysical package containing a γ-ray spectrometer operating at a depth of up to 5 m. The experimental verification of the Monte Carlo model was performed at the FRM II facility in Munich, Germany. The paper demonstrates that the model is in good agreement with the experimental data and can be used to model the performance of an in-situ γ-ray spectrometer.

  20. 14 MeV neutrons physics and applications

    CERN Document Server

    Valkovic, Vladivoj

    2015-01-01

    Despite the often difficult and time-consuming effort of performing experiments with fast (14 MeV) neutrons, these neutrons can offer special insight into nucleus and other materials because of the absence of charge. 14 MeV Neutrons: Physics and Applications explores fast neutrons in basic science and applications to problems in medicine, the environment, and security.Drawing on his more than 50 years of experience working with 14 MeV neutrons, the author focuses on:Sources of 14 MeV neutrons, including laboratory size accelerators, small and sealed tube generators, well logging sealed tube ac

  1. Atmospheric fine and coarse mode aerosols at different environments of India and the Bay of Bengal during winter-2014: Implications of a coordinated campaign

    Digital Repository Service at National Institute of Oceanography (India)

    Sen, A.; Ahammed, Y.N.; Arya, B.C.; Banerjee, T.; Begam, R.G.; Baruah, B.P.; Chatterjee, A.; Choudhuri, A.K.; Dhir, A.; Das, T.; Dhyani, P.P.; Deb, N.C.; Gadi, R.; Gauns, M.; Ghosh, S.K.; Gupta, A.; Sharma, K.C.; Khan, A.H.; Kumari, K.M.; Kumar, M.; Kumar, A.; Kuniyal, J.C.; Lakhani, A.; Meena, R.K.; Mahapatra, P.S.; Naqvi, S.W.A.; Singh, D.P.; Pal, S.; Panda, S.; Rohtash; Saikia, J.; Saikia, P.; Sharma, A.; Sharma, P.; Saxena, M.; Shenoy, D.M.; Vachaspati, C.V.; Sharma, S.K.; Mandal, T.K.

    Division, CSIR-National Physical Laboratory, Dr. K S Krishnan Road, New Delhi 110012, India 2Department of Physics, Yogi Vemana University, Kadapa 516003, India 3Institute of Environment and Sustainable Development, Banaras Hindu University, Banaras, UP..., India 4CSIR-North East Institute of Science and Technology, Jorhat, Assam, India 5Centre for Astroparticle Physics and Space Science, Bose Institute, Kolkata and Darjeeling, West Bengal, India 6Indian Statistical Institute, Giridih, Jharkhand, India 7...

  2. A review of the various techniques of soil rehabilitation in a rural environment following an accidental atmospheric release from a nuclear plant

    International Nuclear Information System (INIS)

    A critical survey of the various rehabilitation methods is presented: mechanical cleanup, physico-chemical treatment, new direction of productions. Particular attention has been paid to the qualification of methods: equipment availability, decontamination efficiency, utilization and maintenance conditions. Two appendices are included: the former presents the broad scope of the RESSAC program (Rehabilitation of Soils and Surfaces following an Accident); the latter a review of the information available on the interventions on the CHERNOBYL site environment

  3. Hydrogen in YBa2Cu3Ox: a neutron spectroscopy and a nuclear magnetic resonance study

    International Nuclear Information System (INIS)

    The high temperature superconductor YBa2Cu3Ox absorbs considerable amounts of hydrogen if it is kept at elevated temperatures in a hydrogen gas atmosphere. In parallel neutron spectroscopic and nuclear magnetic resonance experiments, we studied the vibrational spectra and the spin lattice relaxation time of the protons in YBa2Cu3Ox samples that were doped with hydrogen due to the absorption of hydrogen gas. Both, the vibrational spectra and the spin lattice relaxation time are a sensitive probe for the local environment of the protons. We carried out analogous measurements on samples with a similar proton concentration due to the uptake of water vapour. These experiments demonstrated a totally different local environment of the protons. This fact is a strong indication that the protons absorbed from the hydrogen gas atmosphere did not react with the oxygen of the sample under formation of molecular water. (orig.)

  4. SONTRAC: A solar neutron track chamber detector

    Science.gov (United States)

    Jenkins, T. L.; Frye, G. M., Jr.; Owens, A.

    1985-01-01

    The recent detection on the solar maximum mission (SMM) satellite of high energy neutrons emitted during large solar flares has provided renewed incentive to design a neutron detector which has the sensitivity, energy resolution, and time resolution to measure the neutron time and energy spectra with sufficient precision to improve our understanding of the basic flare processes. Over the past two decades a variety of neutron detectors has been flown to measure the atmospheric neutron intensity above 10 MeV and to search for solar neutrons. The SONTRAC (Solar Neutron Track Chamber) detector, a new type of neutron detector which utilizes n-p scattering and has a sensitivity 1-3 orders of magnitude greater than previous instruments in the 20-200 MeV range is described. The energy resolution is 1% for neutron kinetic energy, T sub n 50 MeV. When used with a coded aperture mask at 50 m (as would be possible on the space station) an angular resolution of approx. 4 arc sec could be achieved, thereby locating the sites of high energy nuclear interactions with an angular precision comparable to the existing x-ray experiments on SMM. The scintillation chamber is investigated as a track chamber for high energy physics, either by using arrays of scintillating optical fibers or by optical imaging of particle trajectories in a block of scintillator.

  5. Methods for absorbing neutrons

    Science.gov (United States)

    Guillen, Donna P.; Longhurst, Glen R.; Porter, Douglas L.; Parry, James R.

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  6. Neutron Measurements for Radiation Protection in Low Earth Orbit - History and Future

    Science.gov (United States)

    Golightly, M. J.; Se,pmes. E/

    2003-01-01

    The neutron environment inside spacecraft has been of interest from a scientific and radiation protection perspective since early in the history of manned spaceflight. With 1:.1e exception of a few missions which carried plutonium-fueled radioisotope thermoelectric generators, all of the neutrons inside the spacecraft are secondary radiations resulting from interactions of high-energy charged particles with nuclei in the Earth's atmosphere, spacecraft structural materials, and the astronaut's own bodies. Although of great interest, definitive measurements of the spacecraft neutron field have been difficult due to the wide particle energy range and the limited available volume and power for traditional techniques involving Bonner spheres. A multitude of measurements, however, have been made of the neutron environment inside spacecraft. The majority of measurements were made using passive techniques including metal activation fo ils, fission foils, nuclear photoemulsions, plastic track detectors, and thermoluminescent detectors. Active measurements have utilized proton recoil spectrometers (stilbene), Bonner Spheres eRe proportional counter based), and LiI(Eu)phoswich scintillation detectors. For the International Space Station (ISS), only the plastic track! thermoluminescent detectors are used with any regularity. A monitoring program utilizing a set of active Bonner spheres was carried out in the ISS Lab module from March - December 200l. These measurements provide a very limited look at the crew neutron exposure, both in time coverage and neutron energy coverage. A review of the currently published data from past flights will be made and compared with the more recent results from the ISS. Future measurement efforts using currently available techniques and those in development will be also discussed.

  7. Neutron Sources for Standard-Based Testing

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McLean, Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-10

    The DHS TC Standards and the consensus ANSI Standards use 252Cf as the neutron source for performance testing because its energy spectrum is similar to the 235U and 239Pu fission sources used in nuclear weapons. An emission rate of 20,000 ± 20% neutrons per second is used for testing of the radiological requirements both in the ANSI standards and the TCS. Determination of the accurate neutron emission rate of the test source is important for maintaining consistency and agreement between testing results obtained at different testing facilities. Several characteristics in the manufacture and the decay of the source need to be understood and accounted for in order to make an accurate measurement of the performance of the neutron detection instrument. Additionally, neutron response characteristics of the particular instrument need to be known and taken into account as well as neutron scattering in the testing environment.

  8. Recent Advances in Neutron Physics

    Science.gov (United States)

    Feshbach, Herman; Sheldon, Eric

    1977-01-01

    Discusses new studies in neutron physics within the last decade, such as ultracold neutrons, neutron bottles, resonance behavior, subthreshold fission, doubly radiative capture, and neutron stars. (MLH)

  9. Application of neutron activation analysis

    International Nuclear Information System (INIS)

    The physical basis and analytical possibilities of neutron activation analysis have been performed. The number of applications in material engineering, geology, cosmology, oncology, criminology, biology, agriculture, environment protection, archaeology, history of art and especially in chemical analysis have been presented. The place of the method among other methods of inorganic quantitative chemical analysis for trace elements determination has been discussed

  10. TIROA/NOAA (Television and Infrared Observation Satellite/National Oceanic and Atmospheric Administration) satellites space environment monitor archive tape documentation: 1988 update. Technical memo

    International Nuclear Information System (INIS)

    TIROS/NOAA satellite archive tapes containing data obtained with the Medium-Energy Proton and Electron Detector (MEPED), High-Energy Proton and Alpha-Particle Detector (HEPAD), and Total-Energy Detector (TED) are described. Descriptions of the data include orbital and housekeeping details and the information needed to decode and understand the data. Specifications of the data channels are supplied, with the timing information needed to convert the data to usable information. Description of the archive tape format gives the information needed to read the tape and unpack the data. Appendices supply the retrieval routines used by the Space Environment Services Center in Boulder

  11. Neutron rich nuclei and neutron stars

    OpenAIRE

    Horowitz, C. J.

    2013-01-01

    The PREX experiment at Jefferson Laboratory measures the neutron radius of 208Pb with parity violating electron scattering in a way that is free from most strong interaction uncertainties. The 208Pb radius has important implications for neutron rich matter and the structure of neutron stars. We present first PREX results, describe future plans, and discuss a follow on measurement of the neutron radius of 48Ca. We review radio and X-ray observations of neutron star masses and radii. These cons...

  12. Method and apparatus for detecting neutrons

    Science.gov (United States)

    Perkins, Richard W.; Reeder, Paul L.; Wogman, Ned A.; Warner, Ray A.; Brite, Daniel W.; Richey, Wayne C.; Goldman, Don S.

    1997-01-01

    The instant invention is a method for making and using an apparatus for detecting neutrons. Scintillating optical fibers are fabricated by melting SiO.sub.2 with a thermal neutron capturing substance and a scintillating material in a reducing atmosphere. The melt is then drawn into fibers in an anoxic atmosphere. The fibers may then be coated and used directly in a neutron detection apparatus, or assembled into a geometrical array in a second, hydrogen-rich, scintillating material such as a polymer. Photons generated by interaction with thermal neutrons are trapped within the coated fibers and are directed to photoelectric converters. A measurable electronic signal is generated for each thermal neutron interaction within the fiber. These electronic signals are then manipulated, stored, and interpreted by normal methods to infer the quality and quantity of incident radiation. When the fibers are arranged in an array within a second scintillating material, photons generated by kinetic neutrons interacting with the second scintillating material and photons generated by thermal neutron capture within the fiber can both be directed to photoelectric converters. These electronic signals are then manipulated, stored, and interpreted by normal methods to infer the quality and quantity of incident radiation.

  13. Neutron activation analysis of arsenic in Greece

    International Nuclear Information System (INIS)

    Arsenic is considered a toxic trace element for plant, animal, and human organisms. Arsenic and certain arsenic compounds have been listed as carcinogens by the U.S. Environmental Protection Agency. Arsenic is emitted in appreciable quantities into the atmosphere by coal combustion and the production of cement. Arsenic enters the aquatic environment through industrial activities such as smelting of metallic ores, metallurgical glassware, and ceramics as well as insecticide production and use. Neutron activation analysis (NAA) is a very sensitive, precise, and accurate method for determining arsenic. This paper is a review of research studies of arsenic in the Greek environment by NAA performed at our radioanalytical laboratory. The objectives of these studies were (a) to determine levels of arsenic concentrations in environmental materials, (b) to pinpoint arsenic pollution sources and estimate the extent of arsenic pollution, and (c) to find out whether edible marine organisms from the gulfs of Greece receiving domestic, industrial, and agricultural wastes have elevated concentrations of arsenic in their tissues that could render them dangerous for human consumption

  14. Exoplanet Atmospheres

    CERN Document Server

    Seager, S

    2010-01-01

    At the dawn of the first discovery of exoplanets orbiting sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of a transiting exoplanet atmosphere, many skeptics discounted it as a one-object, one-method success. Nevertheless, the field is now firmly established, with over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type of exoplanet currently most amenable to study. Highlights include: detection of molecular spectral features; observation of day-night temperature gradients; and constraints on vertical atmospheric structure. Atmospheres of giant planets far from their host stars are also being studied with direct imaging. The ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are we alone?" via detection of atmospheric biosignatures. Two exciting prospects are the immediate focus on transiting super Earths orbiting in the habitable zone of M-dwarfs, and u...

  15. Neutron dosimetry

    International Nuclear Information System (INIS)

    It is the object of the present invention to provide a method of measuring neutron radiation which eliminates the use of powders as dosimeter target materials and reduces the requirement for repetitive weighing of dosimeters, for expensive radioisotopes as dosimeter target material, and for dosimeter housings (in many cases). The invention described is a method of measuring neutron radiation within a nuclear reactor consisting of placing one or more extruded sintered oxide wires comprising a dosimeter target oxide within the reactor and measuring the radioactivity induced in the wires by neutron radiation. These oxide wires consist of a dilution containing at least 0.1% by weight of the dosimeter target oxide in a diluent oxide. The diluent oxide is selected from a group consisting of Al2O3 and BeO. Almost any metal oxide may be used as a target oxide. The wires may be encapsulated within a co-extruded housing. These mixed oxide wires have been found to be sufficiently uniform for quantitative analyses. (JTA)

  16. Neutron scattering

    International Nuclear Information System (INIS)

    The annual report on hand gives an overview of the research work carried out in the Laboratory for Neutron Scattering (LNS) of the ETH Zuerich in 1990. Using the method of neutron scattering, it is possible to examine in detail the static and dynamic properties of the condensed material. In accordance with the multidisciplined character of the method, the LNS has for years maintained a system of intensive co-operation with numerous institutes in the areas of biology, chemistry, solid-state physics, crystallography and materials research. In 1990 over 100 scientists from more than 40 research groups both at home and abroad took part in the experiments. It was again a pleasure to see the number of graduate students present, who were studying for a doctorate and who could be introduced into the neutron scattering during their stay at the LNS and thus were in the position to touch on central ways of looking at a problem in their dissertation using this modern experimental method of solid-state research. In addition to the numerous and interesting ways of formulating the questions to explain the structure, nowadays the scientific programme increasingly includes particularly topical studies in connection with high temperature-supraconductors and materials research

  17. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  18. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)

  19. Pluto's atmosphere

    International Nuclear Information System (INIS)

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

  20. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d