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Sample records for fallout atom ratios

  1. Isotope ratios of (235)U/(238)U and (137)Cs/(235)U in black rain streaks on plaster wall caused by fallout of the Hiroshima atomic bomb.

    PubMed

    Shizuma, Kiyoshi; Endo, Satoru; Fujikawa, Yoko

    2012-02-01

    Radiological investigations of fallout from the atomic bomb detonated over Hiroshima city on 6 August 1945 are important to estimate doses for inhabitants. The authors have analyzed the concentrations of (137)Cs, (235)U, and (238)U in streaks of black rain caused by the atomic bomb using gamma-ray spectroscopy and the ICP-QMS method. The black rain streaks were deposited on a plaster wall of a house located 3.7 km west of the hypocenter that has been kept in the same condition as after the rainfall. Cesium-137 ((137)Cs) was detected from black streak samples. Concentration of (137)Cs in the black rain streaks is twice as high as fallout deposition on the ground in this area. A (235)U/(238)U atom ratio of 0.00887 was found, which is higher than the natural ratio, reflecting the fact that the atomic bomb "Little Boy" used enriched uranium as fuel. The ratio (137)Cs/(235)U was determined to be 0.0091, which is about eight times higher than the estimated ratio of 0.00113 based on the fission yield.

  2. Nevada test site fallout atom ratios: /sup 240/Pu//sup 239/Pu and /sup 241/Pu//sup 239/Pu

    SciTech Connect

    Hicks, H.G.; Barr, D.W.

    1984-02-01

    The exposure of the population in Utah to external gamma radiation from the fallout from nuclear weapons tests carried out between 1951 and 1958 at the Nevada Test Site (NTS) has been reconstructed from recent measurements of /sup 137/Cs and plutonium in soil. The fraction of /sup 137/Cs in the fallout from NTS events was calculated from the total plutonium and the /sup 240/Pu//sup 239/Pu ratios measured in the soil, using the values of 0.180 +- 0.006 and 0.032 +- 0.003 for that ratio in global fallout and NTS fallout, respectively. The total population exposure from NTS events was then calculated on the basis of exposure rates resulting from short-lived radionuclides associated with the /sup 137/Cs at the time of deposition. While the /sup 240/Pu//sup 239/Pu ratio is constant in global fallout, this ratio varies greatly in the fallout from individual events. While the composition of fallout on Utah from NTS events is rather uniform, the Off-Site Radiation Exposure Review Project is currently reconstructing radiation exposures for locations close to NTS where the fallout may be predominantly from one event. Therefore, the authors compiled the pertinent ratios in order to provide information concerning the exposure resulting from any individual event. The plutonium ratios measured at 30 days postshot were compiled from unpublished values in the archives of the Nuclear Chemistry Division of LLNL and INC-11 of LANL. These ratios are pertinent to fallout data. Dates for each event were taken from a publication by the Nevada Operations Office of the Department of Energy. 3 references.

  3. The geochemistry of fallout plutonium in the North Atlantic: II. 240Pu /239Pu ratios and their significance

    NASA Astrophysics Data System (ADS)

    Buesseler, Ken O.; Sholkovitz, Edward R.

    1987-10-01

    A systematic decrease in the 240Pu /239Pu ratio in marine sediments is found with increasing water depth along a transect of cores between Woods Hole and Bermuda. The 240Pu /239Pu atom ratios range from ≅O.18 on the shelf to ≅O.10 at 5000 m but do not change with depth in individual cores. A model is presented which can account for the range of 240Pu /239Pu ratios found in this and other similar studies ( NOSHKIN and GATROUSIS, 1974; SCOTTet al., 1983). We propose that there have been at least two distinct sources of fallout Pu to this region. The major source of Pu is global stratospheric fallout, characterized by a 240Pu /239Pu ratio of 0.18 and a relatively long residence time in seawater. The second source is characterized by a much lower 240Pu /239Pu ratio, and relative to global fallout it must have been much more efficiently removed from the water column to deep-sea sediments. We suggest that surface-based low yield testing at the Nevada Test Site is the only source of low ratio fallout Pu which could account for the timing, inventories, and refractory characteristics of this second component of fallout Pu inputs to the North Atlantic.

  4. Identifying Sources of Non-fallout Nuclear Contamination in Hudson River Sediments by Plutonium and Neptunium isotope ratios.

    NASA Astrophysics Data System (ADS)

    Kenna, T. C.; Chillrud, S. N.

    2002-12-01

    In an effort to identify and characterize nuclear contaminants released from sources contained within the Hudson River drainage basin, Pu isotopes and 237Np have been measured in a series of sediment cores collected from various locations within the region. During the last several decades, the Hudson River has received input of radioactive contamination from several sources. The first and most significant, has been global fallout, which was a result of atmospheric testing of nuclear weapons primarily by governments of the United States and Former Soviet Union in the 1950s and 1960s. The second, is contamination resulting from reactor releases at the Indian Point Nuclear Power Plant (IPNPP) located on the Hudson River about 35 miles north of New York City. This facility began operation in 1962. A third source of radioactive contamination to the region is contamination resulting from activities at the Knolls Atomic Power Laboratory (KAPL) located on the Mohawk River, which began operation in 1946. Our research entails identifying different sources of nuclear contamination by measurement of plutonium and neptunium isotopic ratios by inductively coupled plasma mass spectrometry (ICP-MS). The isotopic composition of a nuclear contaminant is a sensitive indicator of its origin. By comparing the isotopic composition measured in fluvial sediments to mean values reported for global fallout (i.e. 240Pu/239Pu = 0.18 ñ 0.014, 237Np/239Pu = 0.48 ñ 0.07, and 241Pu/239Pu = .00194 ñ 00028) it is possible to identify contaminants as non-fallout in origin. To date, we have analyzed selected samples from 3 sediment cores collected from the following locations: 1) the Mohawk River downstream of KAPL, 2) the Hudson River above its confluence with the Mohawk River, and 3) the lower Hudson River at a location in close proximity to IPNPP. Isotopic analysis of sediments from the Mohawk River indicates contamination that is clearly non-fallout in origin (240Pu/239Pu ranges between 0

  5. Feasibility of using 236U to reconstruct close-in fallout deposition from the Hiroshima atomic bomb.

    PubMed

    Sakaguchi, A; Kawai, K; Steier, P; Imanaka, T; Hoshi, M; Endo, S; Zhumadilov, K; Yamamoto, M

    2010-10-15

    The first results on the feasibility of using (236)U to reconstruct the level and spatial distribution of close-in fallout deposition from the Hiroshima A-bomb are reported, coupled with the use of global fallout (137)Cs and (239+240)Pu. The results for global fallout (236)U in soil samples (0-30cm) from Ishikawa prefecture showed that the deposition density of (236)U from the global fallout can be accurately evaluated using AMS. All deposited (236)U, (137)Cs and (239+240)Pu appeared to have been recovered using 30-cm cores. It was also noted from the depth profiles for (236)U/(239+240)Pu and (236)U/(137)Cs ratios that the downward behavior of (236)U in the soil was apparently similar to that of (239+240)Pu, while the (137)Cs was liable to be retained in upper layers compared with (236)U and (239+240)Pu. The accumulated levels were 1.78×10(13)atomsm(-2) for (236)U, 4340Bqm(-2) for (137)Cs and 141Bqm(-2) for (239+240)Pu. The ratios of (236)U/(137)Cs and (236)U/(239+240)Pu were (4.10±0.12)×10(9) and (1.26±0.04)×10(11)atomsBq(-1), respectively. Results of (236)U, (137)Cs and (239+240)Pu measurements for the seven soil cores (0-30cm) from Hiroshima were discussed on the basis of ratios of (236)U/(137)Cs and (236)U/(239+240)Pu by comparing with those from the background area in Ishikawa, indicating that the global fallout dominates the current level of (236)U accumulation in soil in the Black-rain area around Hiroshima after the Hiroshima bomb, and the contribution of the close-in fallout (236)U produced by the Hiroshima A-bomb seems difficult to observe.

  6. Short-term Fallout Radionuclide Ratios and Mass Balance Identify New Suspended Sediments of Channel Origin

    NASA Astrophysics Data System (ADS)

    Karwan, D. L.; Pizzuto, J. E.; Aalto, R. E.; Marquard, J.; Aufdenkampe, A. K.; Benthem, A.; Skalak, K.; Levia, D. F., Jr.; Siegert, C. M.

    2015-12-01

    Fallout radionuclide ratios, such as the ratio of Beryllium-7 to Lead-210 (7Be/210Pb), are used to determine the age of suspended sediment or fraction of "new" sediment in suspension. In the application of these models new suspended sediment is often assumed to originate from recent landscape surface erosion that is delivered to the stream network. Fallout radionuclide deposition can vary across watersheds and on an event basis in a single watershed due to factors such as storm type, atmospheric height, and storm origin. In the White Clay Creek watershed within the mid-Atlantic USA, single-event deposition of 7Be varies from 15 - 177 Bq m-2 and 210Pb varies from 0 - 10 Bq m-2. 7Be/210Pb ratios vary from 7.9 to 20 in event precipitation and from 0.8 to 12.8 on suspended sediment. "New" sediment varies from 4 - 71% over the course of these events. A computation of the 7Be mass balance during events shows that the majority of 7Be is retained within the catchment. During summer thunderstorms, less than 1% of 7Be deposited on the watershed exits in the stream channel during that event. Therefore, the entirety of the 7Be exiting the watershed on suspended sediment is less than the total activity deposited on the channel in direct precipitation. We attribute this to the new tagging of subaerial fluvial deposits with event precipitation; hence "new" suspended sediment originates from within the channel rather than from surface erosion. During extreme events, such as Hurricane Irene, less of the suspended sediment has been newly tagged by precipitation (4 - 28%) and a larger proportion (3-4%) of the 7Be deposited on the watershed exits during the event. Ongoing work in the Difficult Run watershed in northern Virginia will test the regional applicability of these findings. Water quality efforts to determine the source of sediment using fallout radionuclides must consider the stream channel as well as landscape sources of "new" sediments, particularly during summer

  7. Measurement of the /sup 129/I//sup 131/I ratio in Chernobyl fallout

    SciTech Connect

    Kutschera, W.; Fink, D.; Paul, M.; Hollos, G.; Kaufman, A.

    1986-01-01

    Rainwater collected in the Munich area approximately one week after the Chernobyl reactor accident was investigated for its content of the radioisotopes /sup 129/I (T/sub 1/2/ = 1.6 x 10/sup 7/ y) and /sup 131/I (T/sub 1/2/ = 8.04 d). For the time of release, an isotopic ratio of /sup 129/I//sup 131/I = 19 +- 5 was found. This value was obtained from a gamma-ray activity measurement of /sup 131/I with a GE detector and a concentration measurement of /sup 129/I with accelerator mass spectrometry. From the measured ratio an operating time of the reactor prior to the accident in the vicinity of two years can be estimated, which is in fair agreement with estimates from other long-lived to short-lived radioisotope ratios in the Chernobyl fallout. Some measurements of /sup 131/I activity in thyroids of persons living in the Munich area is also reported.

  8. Fallout from Nuclear Tests.

    ERIC Educational Resources Information Center

    Comar, C. L.

    This booklet, in the series "Understanding the Atom," summarizes the important findings on radioactive fallout for which there is substantial scientific agreement, indicates the areas of disagreement, and lists some answered questions. Sources of fallout, its local and worldwide effects (including movement in the atmosphers), the…

  9. Estimation of beta-ray skin dose from exposure to fission fallout from the Hiroshima atomic bomb.

    PubMed

    Endo, Satoru; Tanaka, Kenichi; Shizuma, Kiyoshi; Hoshi, Masaharu; Imanaka, Tetsuji

    2012-03-01

    Beta-ray skin dose due to the fission fallout from the Hiroshima atomic bomb is potentially related to the epilation in the black rain area. The absorbed dose to the skin from beta-rays emitted by fission fallout has been estimated for an initial ¹³⁷Cs deposition of 1 kBq m⁻² on the ground at 0.5 h after the explosion. The estimated skin dose takes into account both external exposure from fission fallout radionuclides uniformly distributed in 1 mm of soil on the surface of the ground and from a 26 μm thickness of contaminated soil on the skin, using the Monte Carlo radiation transport code MCNP-4C. The cumulative skin dose for 1 month after the explosion is taken as the representative value. The estimated skin dose for an initial ¹³⁷Cs deposition of 1 kBq m⁻² was determined to be about 500 mSv.

  10. Determination of 240Pu/239Pu atom ratio in coastal surface seawaters from the western North Pacific Ocean and Japan Sea.

    PubMed

    Yamada, Masatoshi; Zheng, Jian

    2008-01-01

    Surface seawater samples were collected from a site in the vicinity of the nuclear fuel reprocessing facility at Rokkasho, Japan and sites along the Japan Sea coast. (239+240)Pu activities and (240)Pu/(239)Pu atom ratios were determined by alpha-spectrometry and isotope-dilution sector-field ICP-MS. The (240)Pu/(239)Pu atom ratio with the mean value of 0.227 +/- 0.006 was significantly higher than the mean global fallout ratio of 0.18. The contribution of the Pacific Proving Grounds close-in fallout was estimated to be 33% of the (239+240)Pu.

  11. Global fallout Pu recorded in lacustrine sediments in Lake Hongfeng, SW China.

    PubMed

    Zheng, Jian; Wu, Fengchang; Yamada, Masatoshi; Liao, Haiqing; Liu, Congqiang; Wan, Guojiang

    2008-03-01

    Studies on the distribution and isotope compositions of fallout Pu are important for source characterization of possible future non-fallout Pu contamination in aquatic environments, and useful for dating of recent sediments to understand the pollution history of environmental contaminants. We present the historical record of atmospheric Pu fallout reconstructed from a sediment core from Lake Hongfeng, China. The Pu activity profile was in agreement with the 137Cs profile. Inventories were 50.7 Bq m(-2) for 239+240Pu and 1586 Bq m(-2) for 137Cs. The average 240Pu/239Pu atom ratio was 0.185+/-0.009, indicating that Pu originated from global stratospheric fallout rather than from direct tropospheric or close-in fallout from the Chinese nuclear testing conducted in the 1970s. Our data suggested that Lake Hongfeng would be an ideal setting for monitoring atmospheric fallout and environmental changes in this region.

  12. Pu-239 and Pu-240 inventories and Pu-240/ Pu-239 atom ratios in the water column off Sanriku, Japan.

    NASA Astrophysics Data System (ADS)

    Yamada, Masatoshi; Zheng, Jian; Aono, Tatsuo

    2013-04-01

    -bottom) was 69.8 Bq/m2. This was significantly higher than the expected cumulative deposition density of atmospheric global fallout. The Pu-240/Pu-239 atom ratios were 0.22 in the surface water and increased gradually with depth reaching 0.26 at the 5000 m depth. The obtained Pu-240/Pu-239 atom ratios were higher than the mean global fallout ratio of 0.18. These high atom ratios proved the existence of close-in tropospheric fallout Pu from the Pacific Proving Grounds in the Marshall Islands.

  13. Radioactive fallout

    SciTech Connect

    Shapiro, C.S.; Harvey, T.F.; Peterson, K.R.

    1985-12-01

    Potential radiation doses from several scenarios involving nuclear attack on an unsheltered United States population are calculated for local, intermediate time scale and long-term fallout. Dose estimates are made for both a normal atmosphere and an atmosphere perturbed by smoke produced by massive fires. A separate section discusses the additional doses from nuclear fuel facilities, were they to be targeted in an attack. Finally, in an appendix the direct effects of fallout on humans are considered. These include effects of sheltering and biological repair of damage from chronic doses. 21 refs., 10 figs., 11 tabs.

  14. Short-term Fallout Radionuclide Ratios and Mass Balance Identify New Suspended Sediments of Channel Origin and Importance of Catchment Flowpath

    NASA Astrophysics Data System (ADS)

    Karwan, Diana; Pizzuto, James; Aalto, Rolf; Marquard, Julia; Aufdenkampe, Anthony; Harpold, Adrian; Benthem, Adam; Skalak, Katherine; Levia, Delphis; Siegert, Courtney

    2016-04-01

    Fallout radionuclides and their ratios, such as beryllium-7 (7Be) and lead-210 (210Pb), are used to determine suspended sediment source and age in catchments. The ratio of beryllium-7 to lead-210 (7Be/210Pb) on suspended sediment has been used to estimate the fraction of "new" sediment in suspension. In the application of this model, "new" suspended sediment is often assumed to originate from recent landscape surface erosion that is delivered to the stream network. Fallout radionuclide deposition can vary across watersheds and on an event basis in a single watershed due to factors such as storm type, atmospheric height, and storm origin. In the White Clay Creek watershed within the mid-Atlantic USA, single-event deposition of 7Be varies from 15 - 177 Bq m-2 and 210Pb varies from 0 - 10 Bq m-2. 7Be/210Pb ratios vary from 7.9 to 17 within event precipitation and from 0.8 to 12.8 on suspended sediment. "New" sediment varies from 6 - 100% over the course of these events. 7Be mass balance during events shows that the majority of 7Be is retained within the catchment and not exported on suspended sediment. During summer thunderstorms, less than 1% of 7Be deposited on the watershed exits the stream channel. By comparing this flux with the direct channel interception of 7Be deposition in precipitation and throughfall we can determine the minimum amount of 7Be leaving the watershed that could occur in the absence of surface erosion. For example in summer thunderstorms, the entirety of the 7Be exiting the watershed on suspended sediment is less than the total activity deposited on the channel in direct precipitation. Channel-intercepted fallout radionuclides can exit the catchment by multiple mechanisms including the tagging of subaerial fluvial deposits with event precipitation; hence "new" suspended sediment originates from within the channel rather than from surface erosion. During extreme events, such as Hurricane Irene, less of the suspended sediment has been newly

  15. Determination of Plutonium Activity Concentrations and 240Pu/239Pu Atom Ratios in Brown Algae (Fucus distichus) Collected from Amchitka Island, Alaska.

    SciTech Connect

    Hamilton, T F; Brown, T A; Marchetti, A A; Martinelli, R E; Kehl, S R

    2005-05-02

    Plutonium-239 ({sup 239}Pu) and plutonium-240 ({sup 240}Pu) activity concentrations and {sup 240}Pu/{sup 239}Pu atom ratios are reported for Brown Algae (Fucus distichus) collected from the littoral zone of Amchitka Island (Alaska) and at a control site on the Alaskan peninsula. Plutonium isotope measurements were performed in replicate using Accelerator Mass Spectrometry (AMS). The average {sup 240}Pu/{sup 239}Pu atom ratio observed in dried Fucus d. collected from Amchitka Island was 0.227 {+-} 0.007 (n=5) and compares with the expected {sup 240}Pu/{sup 239}Pu atom ratio in integrated worldwide fallout deposition in the Northern Hemisphere of 0.1805 {+-} 0.0057 (Cooper et al., 2000). In general, the characteristically high {sup 240}Pu/{sup 239}Pu content of Fucus d. analyzed in this study appear to indicate the presence of a discernible basin-wide secondary source of plutonium entering the marine environment. Of interest to the study of plutonium source terms within the Pacific basin are reports of elevated {sup 240}Pu/{sup 239}Pu atom ratios in fallout debris from high-yield atmospheric nuclear tests conducted in the Marshall Islands during the 1950s (Diamond et al., 1960), the wide range of {sup 240}Pu/{sup 239}Pu atom ratio values (0.19 to 0.34) observed in sea water, sediments, coral and other environmental media from the North Pacific Ocean (Hirose et al., 1992; Buesseler, 1997) and updated estimates of the relative contributions of close-in and intermediate fallout deposition on oceanic inventories of radionuclidies, especially in the Northern Pacific Ocean (Hamilton, 2004).

  16. New frequency ratios with a PHz-scale atomic clock

    NASA Astrophysics Data System (ADS)

    McFerran, J. J.

    2016-11-01

    Atomic clocks are a tour de force when it comes to rigorous tests of measurement. The ultimate validation of one’s careful assessments is to find agreement on a given parameter with a completely independent laboratory. Frequency ratios between clock transitions of different atomic species make for quintessential tests of measurement precision. Tyumenev et al (2016 New J. Phys. 18 113002) report on frequency ratio measurements between a 199Hg optical lattice clock and three other atomic frequency standards: 133Cs, 87Rb and 87Sr, two of which are unprecedented in accuracy. Most notable is the level of agreement for the 199Hg/87Sr frequency ratio found between two independent laboratories at 1.7× {10}-16; further indication that optical lattice clocks are fulfilling their early expectations.

  17. THE ATOMIC WEIGHTS COMMISSION AND ISOTOPIC ABUNDANCE RATIO DETERMINATIONS.

    SciTech Connect

    HOLDEN, N.E.

    2005-08-07

    Following Thomson's discovery of stable isotopes in non-radioactive chemical elements, the derivation of atomic weight values from mass spectrometric measurements of isotopic abundance ratios moved very slowly. Forty years later, only 3 1/2 % of the recommended values were based on mass spectrometric measurements and only 38% in the first half century. It might be noted that two chemical elements (tellurium and mercury) are still based on chemical measurements, where the atomic weight value calculated from the relative isotopic abundance measurement either agrees with the value from the chemical measurement or the atomic weight value calculated from the relative isotopic abundance measurement falls within the uncertainty of the chemical measurement of the atomic weight. Of the 19 chemical elements, whose atomic weight is based on non-corrected relative isotopic abundance measurements, five of these are two isotope systems (indium, iridium, lanthanum, lutetium and tantalum) and one is a three-isotope system (oxygen).

  18. Characterization of Pu concentration and its isotopic composition in a reference fallout material.

    PubMed

    Zhang, Yongsan; Zheng, Jian; Yamada, Masatoshi; Wu, Fengchang; Igarashi, Yasuhito; Hirose, Katsumi

    2010-02-01

    Because there is no reference material for fallout plutonium isotope monitoring, preparation of such a material is necessary for quality control of fallout radionuclides analysis for atmospheric environmental studies. In this work, we report the characterization of Pu activity and its isotopic composition in a reference fallout material prepared by the Meteorological Research Institute (MRI), Japan. This material was prepared from samples collected at 14 stations throughout Japan in 1963-1979, with reference values of (137)Cs, (90)Sr and (239)(+)(240)Pu activities. We analyzed the activities of (239)(+)(240)Pu and (241)Pu, and the atom ratios of (240)Pu/(239)Pu and (241)Pu/(239)Pu using an isotope dilution sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS). The (239)(+)(240)Pu activities in this fallout material using acid leaching and total digestion were 6.56+/-0.20 mBq/g and 6.79+/-0.16 mBq/g, respectively. Atom ratios of (240)Pu/(239)Pu were 0.1915+/-0.0030 and 0.1922+/-0.0044, respectively. Both (240)Pu/(239)Pu and (241)Pu/(239)Pu atom ratios were slightly higher than those of global fallout, which could be attributed to the deposition of fallout radionuclides resulting from the Chinese nuclear weapons tests conducted in the 1970s. The dominant host phases of (239)(+)(240)Pu were found to be organic matter-sulfides (70%) with a relative high (240)Pu/(239)Pu atom ratio, and Fe-Mn oxides (19%) using a sequential extraction method.

  19. 135Cs activity and 135Cs/137Cs atom ratio in environmental samples before and after the Fukushima Daiichi Nuclear Power Plant accident

    NASA Astrophysics Data System (ADS)

    Yang, Guosheng; Tazoe, Hirofumi; Yamada, Masatoshi

    2016-04-01

    135Cs/137Cs is a potential tracer for radiocesium source identification. However, due to the challenge to measure 135Cs, there were no 135Cs data available for Japanese environmental samples before the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. It was only 3 years after the accident that limited 135Cs values could be measured in heavily contaminated environmental samples. In the present study, activities of 134Cs, 135Cs, and 137Cs, along with their ratios in 67 soil and plant samples heavily and lightly contaminated by the FDNPP accident were measured by combining γ spectrometry with ICP-MS/MS. The arithmetic means of the 134Cs/137Cs activity ratio (1.033 ± 0.006) and 135Cs/137Cs atom ratio (0.334 ± 0.005) (decay corrected to March 11, 2011), from old leaves of plants collected immediately after the FDNPP accident, were confirmed to represent the FDNPP derived radiocesium signature. Subsequently, for the first time, trace 135Cs amounts before the FDNPP accident were deduced according to the contribution of global and FDNPP accident-derived fallout. Apart from two soil samples with a tiny global fallout contribution, contributions of global fallout radiocesium in other soil samples were observed to be 0.338%–52.6%. The obtained 135Cs/137Cs database will be useful for its application as a geochemical tracer in the future.

  20. 135Cs activity and 135Cs/137Cs atom ratio in environmental samples before and after the Fukushima Daiichi Nuclear Power Plant accident.

    PubMed

    Yang, Guosheng; Tazoe, Hirofumi; Yamada, Masatoshi

    2016-04-07

    (135)Cs/(137)Cs is a potential tracer for radiocesium source identification. However, due to the challenge to measure (135)Cs, there were no (135)Cs data available for Japanese environmental samples before the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. It was only 3 years after the accident that limited (135)Cs values could be measured in heavily contaminated environmental samples. In the present study, activities of (134)Cs, (135)Cs, and (137)Cs, along with their ratios in 67 soil and plant samples heavily and lightly contaminated by the FDNPP accident were measured by combining γ spectrometry with ICP-MS/MS. The arithmetic means of the (134)Cs/(137)Cs activity ratio (1.033 ± 0.006) and (135)Cs/(137)Cs atom ratio (0.334 ± 0.005) (decay corrected to March 11, 2011), from old leaves of plants collected immediately after the FDNPP accident, were confirmed to represent the FDNPP derived radiocesium signature. Subsequently, for the first time, trace (135)Cs amounts before the FDNPP accident were deduced according to the contribution of global and FDNPP accident-derived fallout. Apart from two soil samples with a tiny global fallout contribution, contributions of global fallout radiocesium in other soil samples were observed to be 0.338%-52.6%. The obtained (135)Cs/(137)Cs database will be useful for its application as a geochemical tracer in the future.

  1. 135Cs activity and 135Cs/137Cs atom ratio in environmental samples before and after the Fukushima Daiichi Nuclear Power Plant accident

    PubMed Central

    Yang, Guosheng; Tazoe, Hirofumi; Yamada, Masatoshi

    2016-01-01

    135Cs/137Cs is a potential tracer for radiocesium source identification. However, due to the challenge to measure 135Cs, there were no 135Cs data available for Japanese environmental samples before the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. It was only 3 years after the accident that limited 135Cs values could be measured in heavily contaminated environmental samples. In the present study, activities of 134Cs, 135Cs, and 137Cs, along with their ratios in 67 soil and plant samples heavily and lightly contaminated by the FDNPP accident were measured by combining γ spectrometry with ICP-MS/MS. The arithmetic means of the 134Cs/137Cs activity ratio (1.033 ± 0.006) and 135Cs/137Cs atom ratio (0.334 ± 0.005) (decay corrected to March 11, 2011), from old leaves of plants collected immediately after the FDNPP accident, were confirmed to represent the FDNPP derived radiocesium signature. Subsequently, for the first time, trace 135Cs amounts before the FDNPP accident were deduced according to the contribution of global and FDNPP accident-derived fallout. Apart from two soil samples with a tiny global fallout contribution, contributions of global fallout radiocesium in other soil samples were observed to be 0.338%–52.6%. The obtained 135Cs/137Cs database will be useful for its application as a geochemical tracer in the future. PMID:27052481

  2. Epiphytic fruticose lichens as biomonitors for retrospective evaluation of the (134)Cs/(137)Cs ratio in Fukushima fallout.

    PubMed

    Ramzaev, V; Barkovsky, A; Gromov, A; Ivanov, S; Kaduka, M

    2014-12-01

    In 2011-2013, sampling of epiphytic fruticose lichens of the genera Usnea, Bryoria and Alectoria was carried out on Sakhalin and Kuril Islands (the Sakhalin region, Russia) to investigate contamination of these organisms with the Fukushima-derived (134)Cs and (137)Cs. Activities of the radionuclides were determined in all 56 samples of lichens taken for the analysis. After correction for radioactive decay (on 15 March 2011), the activity concentrations ranged from 2.1 Bq kg(-1) (d.w.) to 52 Bq kg(-1) for (134)Cs and from 2.3 Bq kg(-1) to 52 Bq kg(-1) for (137)Cs. Cesium-134 and (137)Cs activities for the whole set of lichens (n = 56) were strongly positively correlated; Spearman's rank correlation coefficient was calculated as 0.991 (P < 0.01). The activity concentrations of (134)Cs and (137)Cs in Usnea lichens from the Sakhalin and Kunashir islands declined with a factor of three in the period from 2011 to 2013. The average biological half-time for both cesium radionuclides in lichens of the genus Usnea is estimated as 1.3 y. The mean of 0.99 ± 0.10 and median of 0.99 were calculated for the decay corrected (134)Cs/(137)Cs activities ratios in the lichens (n = 56). The radionuclides ratio in the lichens did not depend on location of sampling site, species and the time that had passed after the Fukushima accident. The regression analysis has shown the background pre-Fukushima level of (137)Cs of 0.4 ± 0.3 Bq kg(-1), whereas the ratio between the Fukushima-borne (134)Cs and (137)Cs in the lichens was estimated as 1.04. The (134)Cs/(137)Cs activities ratio in lichens from the Sakhalin region is consistent with the ratios reported by others for the heavy contaminated areas on Honshu Island in Japan following the Fukushima accident. The activity concentrations of natural (7)Be in lichens from the Sakhalin region varied between 100 Bq kg(-1) and 600 Bq kg(-1); the activity concentrations did not exhibit temporal variations during a 2y

  3. Inventory and vertical migration of 90Sr fallout and 137Cs/90Sr ratio in Spanish mainland soils.

    PubMed

    Herranz, M; Romero, L M; Idoeta, R; Olondo, C; Valiño, F; Legarda, F

    2011-11-01

    In this paper the inventory of (90)Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m(2) and 2047 Bq/m(2). From these data set and those (137)Cs data obtained in a previous work the (137)Cs/(90)Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for (137)Cs an average value 57% lower than that obtained for (90)Sr. Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective-diffusive model, the parameters of the model which governs the vertical migration of (90)Sr in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm(2)/year, respectively.

  4. ²³⁹Pu and ²⁴⁰Pu inventories and ²⁴⁰Pu/²³⁹Pu atom ratios in the equatorial Pacific Ocean water column.

    PubMed

    Yamada, Masatoshi; Zheng, Jian

    2012-07-15

    The (239+240)Pu concentrations and (240)Pu/(239)Pu atom ratios were determined by alpha spectrometry and inductively coupled plasma mass spectrometry for seawater samples from two stations, one at the equator and the other in the equatorial South Pacific. To better understand the fate of Pu isotopes, this study dealt with the contribution of the close-in fallout Pu from the Pacific Proving Grounds (PPG) in water columns of the Pacific Ocean. The (239)Pu, (240)Pu and (239+240)Pu inventories over the depth interval 0-3000 m at the equator station were 10.4, 8.9 and 19.3 Bq m(-2), respectively. Further, no noticeable difference was observed in (239)Pu, (240)Pu and (239+240)Pu inventories over the depth interval 0-3000 m between the two stations. The total (239+240)Pu inventories were significantly higher than the expected cumulative deposition density of global fallout. Water column (239+240)Pu inventories measured in this study were lower than those reported for comparable stations in the Geochemical Ocean Sections Study, indicating that these inventories have been decreasing at average rates of 0.89 ± 0.07 and 0.16 ± 0.07 Bq m(-2)yr(-1) at the equator and equatorial South Pacific stations, respectively, from 1973 to 1990. The obtained (240)Pu/(239)Pu atom ratios were higher than the mean global fallout ratio of 0.18. These high atom ratios proved the existence of close-in tropospheric fallout Pu from the PPG in the Marshall Islands. The (239+240)Pu inventories originating from the close-in fallout in the entire water column were estimated to be 11.1 Bq m(-2) at the equator station and 7.1 Bq m(-2) at the equatorial South Pacific Ocean station, and the relative percentages of close-in fallout Pu were 40% at the former and 34% at the latter. A significant amount of close-in fallout Pu originating from the PPG has been transported to deep layers below the 1000 m depth in the equatorial Pacific Ocean.

  5. Pu isotopes in soils collected downwind from Lop Nor: regional fallout vs. global fallout

    NASA Astrophysics Data System (ADS)

    Bu, Wenting; Ni, Youyi; Guo, Qiuju; Zheng, Jian; Uchida, Shigeo

    2015-07-01

    For the first time, soil core samples from the Jiuquan region have been analyzed for Pu isotopes for radioactive source identification and radiological assessment. The Jiuquan region is in downwind from the Lop Nor Chinese nuclear test (CNT) site. The high Pu inventories (13 to 546 Bq/m2) in most of the sampling locations revealed that this region was heterogeneously contaminated by the regional fallout Pu from the CNTs. The contributions of the CNTs to the total Pu in soils were estimated to be more than 40% in most cases. The 240Pu/239Pu atom ratios in the soils ranged from 0.059 to 0.186 with an inventory-weighted average of 0.158, slightly lower than that of global fallout. This atom ratio could be considered as a mixed fingerprint of Pu from the CNTs. In addition, Pu in soils of Jiuquan region had a faster downward migration rate compared with other investigated places in China.

  6. Pu isotopes in soils collected downwind from Lop Nor: regional fallout vs. global fallout.

    PubMed

    Bu, Wenting; Ni, Youyi; Guo, Qiuju; Zheng, Jian; Uchida, Shigeo

    2015-07-17

    For the first time, soil core samples from the Jiuquan region have been analyzed for Pu isotopes for radioactive source identification and radiological assessment. The Jiuquan region is in downwind from the Lop Nor Chinese nuclear test (CNT) site. The high Pu inventories (13 to 546 Bq/m(2)) in most of the sampling locations revealed that this region was heterogeneously contaminated by the regional fallout Pu from the CNTs. The contributions of the CNTs to the total Pu in soils were estimated to be more than 40% in most cases. The (240)Pu/(239)Pu atom ratios in the soils ranged from 0.059 to 0.186 with an inventory-weighted average of 0.158, slightly lower than that of global fallout. This atom ratio could be considered as a mixed fingerprint of Pu from the CNTs. In addition, Pu in soils of Jiuquan region had a faster downward migration rate compared with other investigated places in China.

  7. Pu isotopes in soils collected downwind from Lop Nor: regional fallout vs. global fallout

    PubMed Central

    Bu, Wenting; Ni, Youyi; Guo, Qiuju; Zheng, Jian; Uchida, Shigeo

    2015-01-01

    For the first time, soil core samples from the Jiuquan region have been analyzed for Pu isotopes for radioactive source identification and radiological assessment. The Jiuquan region is in downwind from the Lop Nor Chinese nuclear test (CNT) site. The high Pu inventories (13 to 546 Bq/m2) in most of the sampling locations revealed that this region was heterogeneously contaminated by the regional fallout Pu from the CNTs. The contributions of the CNTs to the total Pu in soils were estimated to be more than 40% in most cases. The 240Pu/239Pu atom ratios in the soils ranged from 0.059 to 0.186 with an inventory-weighted average of 0.158, slightly lower than that of global fallout. This atom ratio could be considered as a mixed fingerprint of Pu from the CNTs. In addition, Pu in soils of Jiuquan region had a faster downward migration rate compared with other investigated places in China. PMID:26184740

  8. Valence atom with bohmian quantum potential: the golden ratio approach

    PubMed Central

    2012-01-01

    Background The alternative quantum mechanical description of total energy given by Bohmian theory was merged with the concept of the golden ratio and its appearance as the Heisenberg imbalance to provide a new density-based description of the valence atomic state and reactivity charge with the aim of clarifying their features with respect to the so-called DFT ground state and critical charge, respectively. Results The results, based on the so-called double variational algorithm for chemical spaces of reactivity, are fundamental and, among other issues regarding chemical bonding, solve the existing paradox of using a cubic parabola to describe a quadratic charge dependency. Conclusions Overall, the paper provides a qualitative-quantitative explanation of chemical reactivity based on more than half of an electronic pair in bonding, and provide new, more realistic values for the so-called “universal” electronegativity and chemical hardness of atomic systems engaged in reactivity (analogous to the atoms-in-molecules framework). PMID:23146157

  9. Distribution of Np and Pu in Swedish lichen samples (Cladonia stellaris) contaminated by atmospheric fallout.

    PubMed

    Lindahl, Patric; Roos, Per; Eriksson, Mats; Holm, Elis

    2004-01-01

    The activity concentrations of (237)Np and the two Pu isotopes, (239)Pu and (240)Pu, were determined in lichen samples (Cladonia stellaris) contaminated by fallout from atmospheric nuclear test explosions and the Chernobyl accident. The samples were collected at 18 locations in Sweden, from north to south, between 1986 and 1988 and analysed with high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) and alpha spectrometry. Data on the activity ratios (238)Pu/(239+240)Pu and (134)Cs/(137)Cs measured previously were also included in this study for comparison. The (237)Np activity concentration ranged from 0.08 +/- 0.01 to 2.08 +/- 0.17 MBq kg(-1), depending on the location of the sampling site and time of collection. The (239+240)Pu activity concentration ranged from 0.09 +/- 0.01 to 4.09 +/- 0.15 Bq kg(-1), with the (240)Pu/(239)Pu atomic ratio ranging between 0.16 +/- 0.01 and 0.44 +/- 0.03, the higher ratios indicating a combination of weapons test fallout and Chernobyl fallout. The (237)Np/(239)Pu atomic ratios ranged between 0.06 +/- 0.01 and 0.42 +/- 0.04, the lower ratios indicating combination of weapons test fallout and Chernobyl fallout. At a well-defined sampling site at Lake Rogen (62.32 degrees N, 12.38 degrees E), additional lichen samples were collected between 1987 and 1998 to study the distribution of Np and Pu in different layers. The concentrations of the two elements follow each other quite well in the profile.

  10. Analysis of actinides in an ombrotrophic peat core - evidence of post-depositional migration of fallout radionuclides

    NASA Astrophysics Data System (ADS)

    Quinto, Francesca; Hrnecek, Erich; Krachler, Michael; Shotyk, William; Steier, Peter; Winkler, Stephan R.

    2013-04-01

    Plutonium (239Pu, 240Pu, 241Pu, 242Pu) and uranium (236U, 238U) isotopes were analyzed in an ombrotrophic peat core from the Black Forest, Germany, representing the last 80 years of atmospheric deposition. The reliable determination of these isotopes at ultra-trace levels was possible using ultra-clean laboratory procedures and accelerator mass spectrometry. The 240Pu/239Pu isotopic ratios are constant along the core with a mean value of 0.19 ±0.02 (N = 32). This result is consistent with the acknowledged average 240Pu/239Pu isotopic ratio from global fallout in the Northern Hemisphere. The global fallout origin of Pu is confirmed by the corresponding 241Pu/239Pu (0.0012 ±0.0005) and 242Pu/239Pu (0.004 ± 0.001) isotopic ratios. The identification of the Pu isotopic composition characteristic for global fallout in peat layers pre-dating the period of atmospheric atom bomb testing (AD 1956 - AD 1980) is a clear evidence of the migration of Pu downwards the peat profile. The maximum of global fallout derived 236U is detected in correspondence to the age/depth layer of maximum stratospheric fallout (AD 1963). This finding demonstrates that the 236U bomb peak can be successfully used as an independent chronological marker complementing the 210Pb dating of peat cores. The profiles of the global fallout derived 236U and 239Pu are compared with those of 137Cs and 241Am. As typical of ombrothrophic peat, the temporal fallout pattern of 137Cs is poorly retained. Similarly like for Pu, post-depositional migration of 241Am in peat layers preceding the era of atmospheric nuclear tests is observed.

  11. Application of the ORIGEN Fallout Analysis Tool and the DELFIC Fallout Planning Tool to National Technical Nuclear Forensics

    SciTech Connect

    Jodoin, Vincent J; Lee, Ronald W; Peplow, Douglas E.; Lefebvre, Jordan P

    2011-01-01

    The objective of this project was to provide a robust fallout analysis and planning tool for the National Technical Nuclear Forensics interagency ground sample collection team. Their application called for a fast-running, portable mission-planning tool for use in response to emerging improvised nuclear device (IND) post-detonation situations. The project met those goals by research and development of models to predict the physical, chemical, and radiological properties of fallout debris. ORNL has developed new graphical user interfaces for two existing codes, the Oak Ridge Isotope Generation (ORIGEN) code and the Defense Land Fallout Interpretive Code (DELFIC). ORIGEN is a validated, radionuclide production and decay code that has been implemented into the Fallout Analysis Tool to predict the fallout source term nuclide inventory after the detonation of an IND. DELFIC is a validated, physics-based, research reference fallout prediction software package. It has been implemented into the Fallout Planning Tool and is used to predict the fractionated isotope concentrations in fallout, particle sizes, fractionation ratios, dose rate, and integrated dose over the planned collection routes - information vital to ensure quality samples for nuclear forensic analysis while predicting dose to the sample collectors. DELFIC contains a particle activity module, which models the radiochemical fractionation of the elements in a cooling fireball as they condense into and onto particles to predict the fractionated activity size distribution for a given scenario. This provides the most detailed physics-based characterization of the fallout source term phenomenology available in an operational fallout model.

  12. Plutonium isotope ratio variations in North America

    SciTech Connect

    Steiner, Robert E; La Mont, Stephen P; Eisele, William F; Fresquez, Philip R; Mc Naughton, Michael; Whicker, Jeffrey J

    2010-12-14

    Historically, approximately 12,000 TBq of plutonium was distributed throughout the global biosphere by thermo nuclear weapons testing. The resultant global plutonium fallout is a complex mixture whose {sup 240}Pu/{sup 239}Pu atom ratio is a function of the design and yield of the devices tested. The average {sup 240}Pu/{sup 239}Pu atom ratio in global fallout is 0.176 + 014. However, the {sup 240}Pu/{sup 239}Pu atom ratio at any location may differ significantly from 0.176. Plutonium has also been released by discharges and accidents associated with the commercial and weapons related nuclear industries. At many locations contributions from this plutonium significantly alters the {sup 240}Pu/{sup 239}Pu atom ratios from those observed in global fallout. We have measured the {sup 240}Pu/{sup 239}Pu atom ratios in environmental samples collected from many locations in North America. This presentation will summarize the analytical results from these measurements. Special emphasis will be placed on interpretation of the significance of the {sup 240}Pu/{sup 239}Pu atom ratios measured in environmental samples collected in the Arctic and in the western portions of the United States.

  13. 137Cs, 239+240Pu and 240Pu/239Pu atom ratios in the surface waters of the western North Pacific Ocean, eastern Indian Ocean and their adjacent seas.

    PubMed

    Yamada, Masatoshi; Zheng, Jian; Wang, Zhong-Liang

    2006-07-31

    Surface seawater samples were collected along the track of the R/V Hakuho-Maru cruise (KH-96-5) from Tokyo to the Southern Ocean. The (137)Cs activities were determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas, the eastern Indian Ocean, the Bay of Bengal, the Andaman Sea, and the South China Sea. The (137)Cs activities showed a wide variation with values ranging from 1.1 Bq m(-3) in the Antarctic Circumpolar Region of the Southern Ocean to 3 Bq m(-3) in the western North Pacific Ocean and the South China Sea. The latitudinal distributions of (137)Cs activity were not reflective of that of the integrated deposition density of atmospheric global fallout. The removal rates of (137)Cs from the surface waters were roughly estimated from the two data sets of Miyake et al. [Miyake Y, Saruhashi K, Sugimura Y, Kanazawa T, Hirose K. Contents of (137)Cs, plutonium and americium isotopes in the Southern Ocean waters. Pap Meteorol Geophys 1988;39:95-113] and this study to be 0.016 yr(-1) in the Sulu and Indonesian Seas, 0.033 yr(-1) in the Bay of Bengal and Andaman Sea, and 0.029 yr(-1) in the South China Sea. These values were much lower than that in the coastal surface water of the western Northwest Pacific Ocean. This was likely due to less horizontal and vertical mixing of water masses and less scavenging. (239+240)Pu activities and (240)Pu/(239)Pu atom ratios were also determined for the surface waters in the western North Pacific Ocean, the Sulu and Indonesian Seas and the South China Sea. The (240)Pu/(239)Pu atom ratios ranged from 0.199+/-0.026 to 0.248+/-0.027 on average, and were significantly higher than the global stratospheric fallout ratio of 0.18. The contributions of the North Pacific Proving Grounds close-in fallout Pu were estimated to be 20% for the western North Pacific Ocean, 39% for the Sulu and Indonesian Seas and 42% for the South China Sea by using the two end-member mixing model. The higher (240)Pu/(239)Pu

  14. Fallout from atmospheric bomb tests and releases from nuclear installations

    NASA Astrophysics Data System (ADS)

    Völkle, H.; Murith, C.; Surbeck, H.

    This work presents the radioactivity monitoring programme in Switzerland. Environmental radioactivity measurements for atomic bomb test fallout are discussed together with the radiation doses to the public caused by fallout. In the second part the monitoring programme around nuclear power stations is presented. The radioactivity releases to the environment, the results of the monitoring programme and the radiation doses to the public in the vicinity of the plants are discussed.

  15. Determination of Pu isotopes and 241Am in a reference fallout material using SF-ICP-MS.

    PubMed

    Zheng, Jian; Zhang, Yongsan; Yamada, Masatoshi; Wu, Fengchang; Igarashi, Yasuhito; Hirose, Katsumi

    2011-07-01

    This paper reports on the characterisation of activities of Pu and (241)Am, and Pu isotopic composition in a reference fallout material prepared by the Meteorological Research Institute (MRI), Japan, from samples collected at 14 stations throughout Japan in 1963-1979. The acid leaching and total digestion were used to compare whether there is difference in Pu and (241)Am activities and Pu isotopic composition between these two methods. The results of activities of (239+240)Pu and (241)Pu, and Pu isotopic composition have been reported in the previous work (Sci. Total Environ. 2010, 408, 1139-1144). In this study, the (241)Am activity and (241)Am/(239+240)Pu activity ratio in the reference fallout material are reported, and the usefulness of Pu atom ratios and (241)Am/(239+240)Pu activity ratio for source identification is discussed.

  16. Variations of 129I in the atmospheric fallout of Tokyo, Japan: 1963-2003.

    PubMed

    Toyama, Chiaki; Muramatsu, Yasuyuki; Uchida, Yuka; Igarashi, Yasuhito; Aoyama, Michio; Matsuzaki, Hiroyuki

    2012-11-01

    Atmospheric fallout samples collected from Tokyo between 1963 and 2003 were analyzed using accelerator mass spectrometry (AMS) in order to determine (129)I/(127)I ratios and to examine the deposition rate of (129)I and its secular variation in Tokyo. The (129)I/(127)I ratios in the atmosphere during 1963-1977 ranged from 1 × 10(-8) to 2 × 10(-8). This is roughly 4 orders of magnitude higher than pre-atomic levels, possibly due to atmospheric nuclear weapons tests. The calculated monthly atmospheric deposition rates of (129)I differed from those produced by nuclear fallout of (90)Sr and (137)Cs, indicating that the variations in (129)I deposition are not influenced exclusively by either nuclear bomb testing or by the Chernobyl accident. After 1978, high (129)I depositions (up to 0.13 mBq/m(2)/month) were observed. The (129)I depositions started to increase markedly at the latter half of the 1970s. The secular variation of the estimated annual (129)I deposition in Tokyo showed a close relationship between the annual atmospheric discharge of (129)I from the Tokai Reprocessing plant. Therefore, the atmospheric fallout collected from Tokyo after the late 1970s is influenced primary by the (129)I discharge from the Tokai Reprocessing plant.

  17. Modeling fallout of anthropogenic 129I.

    PubMed

    Englund, Edvard; Aldahan, Ala; Possnert, Göran; Haltia-Hovi, Eeva; Hou, Xiaolin; Renberg, Ingmar; Saarinen, Timo

    2008-12-15

    Despite the relatively well-recognized emission rates of the anthropogenic 129I, there is little knowledge about the temporal fallout patterns and magnitude of fluxes since the start of the atomic era atthe early 1940s. We here present measurements of annual 129I concentrations in sediment archives from Sweden and Finland covering the period 1942-2006. The results revealed impression of 129I emissions from the nuclear reprocessing facility at Sellafield and La Hague and a clear Chernobyl fallout enhancement during 1986. In order to estimate relative contributions from the different sources, a numerical model approach was used taking into accountthe emission rates/estimated fallout, transport pathways, and the sediment system. The model outcomes suggest a relatively dominating marine source of 129I to north Europe compared to direct gaseous releases. A transfer rate of 129I from sea to atmosphere is derived for pertinent sea areas (English Channel, Irish Sea, and North Sea), which is estimated at 0.04 to 0.21 y(-1).

  18. C12/C13-ratio determination in nanodiamonds by atom-probe tomography.

    PubMed

    Lewis, Josiah B; Isheim, Dieter; Floss, Christine; Seidman, David N

    2015-12-01

    The astrophysical origins of ∼ 3 nm-diameter meteoritic nanodiamonds can be inferred from the ratio of C12/C13. It is essential to achieve high spatial and mass resolving power and minimize all sources of signal loss in order to obtain statistically significant measurements. We conducted atom-probe tomography on meteoritic nanodiamonds embedded between layers of Pt. We describe sample preparation, atom-probe tomography analysis, 3D reconstruction, and bias correction. We present new data from meteoritic nanodiamonds and terrestrial standards and discuss methods to correct isotopic measurements made with the atom-probe tomograph.

  19. First results on 236U levels in global fallout.

    PubMed

    Sakaguchi, A; Kawai, K; Steier, P; Quinto, F; Mino, K; Tomita, J; Hoshi, M; Whitehead, N; Yamamoto, M

    2009-07-01

    The global fallout (236)U level in soil was deduced from measurements of (236)U, (239+240)Pu and (137)Cs in surface soils which are solely influenced by global fallout. A total of 12 soil cores from the depths of 0-10, 0-20 and 0-30 cm were collected at a flat forest area in Japan. Concentrations of (239+240)Pu and (238)U were determined by alpha-particle spectrometry, while the (236)U/(238)U ratio was measured with accelerator mass spectrometry (AMS). Consistent (236)U/(239)Pu ratios between 0.212 and 0.253 were found. Using this ratio, the total global fallout of (236)U on the earth is estimated to be as much as ca. 900 kg. This knowledge will contribute to the promotion of research on U isotopes, including (236)U, for the fields of geo-resources, waste management and geochemistry.

  20. Optoelectronic Particle-Fallout Sensor

    NASA Technical Reports Server (NTRS)

    Ihlefeld, Curtis; Mogan, Paul A.; Youngquist, Robert C.; Moerk, John S.; Haskell, William D.; Cox, Robert B.; Rose, Kenneth A.

    1995-01-01

    Portable optoelectronic system monitors fallout of small particles (dust and fibers) onto surface at given location during extended time. Data on accumulated fallout downloaded from system to computer for display and analysis. Typical display is plot of signal proportional to amount of accumulated fallout as function of time and read to determine when contamination occurs. In many cases, possible to establish correlations between accumulations of particles and activities in vicinity. Also capable of signaling alarm in event contamination by fallout exceeds specified level. System made very inexpensively and used to monitor accumulation of dust and fibers associated with motion of air in variety of environments. Phenomena monitored indirectly by use of system might include circulation of air in buildings, and human and animal activity. Also serves as auxiliary intrusion monitor (though probably not real-time alarm) in sealed room because motion of intruder inevitably stirs up some dust.

  1. Distribution of nuclear bomb Pu in Nishiyama area, Nagasaki, estimated by accurate and precise determination of 240Pu/239Pu ratio in soils.

    PubMed

    Yoshida, S; Muramatsu, Y; Yamazaki, S; Ban-Nai, T

    2007-01-01

    Plutonium isotopes in forest soils collected in Nishiyama area, Nagasaki, were successfully determined by high resolution inductively coupled plasma mass spectrometry after the treatment with a microwave decomposition system. The (240)Pu/(239)Pu atom ratios observed in the samples in the Nishiyama area were obviously lower than the range of the global fallout. The low ratios (minimum 0.032) observed in Nishiyama area indicated the influence of detonation of the Pu nuclear weapon in 1945. Since the area is contaminated also by global fallout, the (240)Pu/(239)Pu atom ratio can be more sensitive indicator of bomb-derived Pu than Pu activity concentration.

  2. Fallout: its characteristics and management. Technical report

    SciTech Connect

    Ferlic, K.P.

    1983-12-01

    This report is a comprehensive single-source summary of the salient features of fallout. It supplements the fallout lectures of the Medical Effects of Nuclear Weapons course given by AFRRI. The following topics are included: Basic physical processes that give rise to formation of fallout; identification of primary factors governing magnitude of the fallout problem; design and deployment of weapons and their effect on fallout formation; sources of fallout; weapon yield and atmospheric structure in region of detonation, including effects of local meteorological conditions on early fallout; theoretical and actual fallout patterns, with emphasis on the latter and on experience gained from atmospheric testing; expected type of fallout deposition; identification of types of radiation associated with fallout, and discussion of their radiological properties; protection against each type of radiation; external hazards of fallout; major concerns of ingesting fallout; discussion of each major isotope of concern with particular attention to current ICRP (International Commission on Radiation Protection) dose estimates for ingestion; brief description of management of fallout, including (a) detection of fallout and evaluation of hazards based or radiological dose considerations, fallout shelters, personnel decontamination, and food sources, and (b) postattack recovery.

  3. Branching ratio for the hydrogen atom product channel in the reaction of ground-state atomic oxygen with ethylene

    SciTech Connect

    Smalley, J.F.; Nesbitt, F.L.; Klemm, R.B.

    1986-01-30

    The branching ratio, ..cap alpha../sub 1/, for the H + C/sub 2/H/sub 3/O product channel of the O(/sup 3/P) + C/sub 2/H/sub 3/O reaction was determined from measured H- and O-atom profiles in this flash photolysis-resonance fluorescence study. The relative detection sensitivity of the system for H and O atoms was determined experimentally. A chemical model was used to describe the reaction mechanism together with the relative detection sensitivity, and a value of ..cap alpha../sub 1/ = 0.27 +/- 0.05 was derived at 300 K. At higher temperatures, the value of ..cap alpha../sub 1/ appears to increase slightly. Possible reasons for this increase are discussed. 30 references, 2 figures, 7 tables.

  4. FALLOUT DOSAGE AND MONITORING

    PubMed Central

    Kinsman, Simon

    1960-01-01

    At present there are a large number of people capable of conducting the task of surface and area radiation monitoring including external monitoring of personnel. Once the extent and the intensity of radioactivity in an area is determined, good use of personnel can be made without too much risk. This is fortunate for the medical profession whose personnel can devote their talents to casualty care during or following nuclear warfare. Most individuals who know how to detect and measure the extent of radioactive contamination are also capable of conducting personnel decontamination operations and would do so if necessary. Consequently the spread of contamination can be minimized by adequate decontamination and the medical personnel can treat casualties who are relatively free of external radioactive contamination. The appropriate use of trained manpower and radiation detection equipment which are available in California combined with sufficient rehearsals prior to a nuclear war will greatly reduce any casualty damage due to radioactive fallout. The chances of survival of individuals can be greatly improved with a little knowledge of protection from radioactive contamination and of salvage of food and water. PMID:14409247

  5. Plutonium concentration and (240)Pu/(239)Pu atom ratio in biota collected from Amchitka Island, Alaska: recent measurements using ICP-SFMS.

    PubMed

    Bu, Kaixuan; Cizdziel, James V; Dasher, Douglas

    2013-10-01

    Three underground nuclear tests, including the Unites States' largest, were conducted on Amchitka Island, Alaska. Monitoring of the radiological environment around the island is challenging because of its remote location. In 2008, the Department of Energy (DOE) Office of Legacy Management (LM) became responsible for the long term maintenance and surveillance of the Amchitka site. The first DOE LM environmental survey occurred in 2011 and is part of a cycle of activities that will occur every 5 years. The University of Alaska Fairbanks, a participant in the 2011 study, provided the lichen (Cladonia spp.), freshwater moss (Fontinalis neomexicanus), kelp (Eualaria fistulosa) and horse mussel (Modiolus modiolus) samples from Amchitka Island and Adak Island (a control site). These samples were analyzed for (239)Pu and (240)Pu concentration and (240)Pu/(239)Pu atom ratio using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). Plutonium concentrations and (240)Pu/(239)Pu atom ratios were generally consistent with previous terrestrial and marine studies in the region. The ((239)+)(240)Pu levels (mBq kg(-1), dry weight) ranged from 3.79 to 57.1 for lichen, 167-700 for kelp, 27.9-148 for horse mussel, and 560-573 for moss. Lichen from Adak Island had higher Pu concentrations than Amchitka Island, the difference was likely the result of the higher precipitation at Adak compared to Amchitka. The (240)Pu/(239)Pu atom ratios were significantly higher in marine samples compared to terrestrial and freshwater samples (t-test, p < 0.001); lichen and moss averaged 0.184 ± 0.007, similar to the integrated global fallout ratio, whereas kelp and mussel (soft tissue) averaged 0.226 ± 0.003. These observations provide supporting evidence that a large input of isotopically heavier Pu occurred into the North Pacific Ocean, likely from the Marshall Island high yield nuclear tests, but other potential sources, such as the Kamchatka Peninsula Rybachiy Naval Base and

  6. Fukushima fallout in Northwest German environmental media.

    PubMed

    Pittauerová, Daniela; Hettwig, Bernd; Fischer, Helmut W

    2011-09-01

    Traces of short- and long-lived fallout isotopes ((131)I, (134)Cs and (137)Cs) were found in environmental samples collected in Northwest Germany (rain water, river sediment, soil, grass and cow milk) from March to May 2011, following the radioactivity releases after the nuclear accident in Fukushima, Japan. The measured concentrations are consistent with reported concentrations in air, amount of rainfall and expected values applying simple radioecological models. The [(134)Cs]/[(137)Cs] ratio reported for air (about 1) allows for discrimination between "recent" and "old"(137)Cs. Expected (136)Cs values fell below the detection limits of the instrumentation, despite large sample masses and long counting times.

  7. Precise determination of atomic g-factor ratios from a dual isotope magneto-optical trap

    SciTech Connect

    Chan, I.; Barrett, B.; Kumarakrishnan, A.

    2011-09-15

    We demonstrate a technique, for carrying out precise measurements of atomic g-factor ratios, which relies on measurements of Larmor oscillations from coherences between magnetic sublevels in the ground states of {sup 85}Rb and {sup 87}Rb atoms confined in a dual isotope magneto-optical trap. We show that a measurement of g{sub F}{sup (87)}/g{sub F}{sup (85)} with a resolution of 0.69 parts per 10{sup 6} is possible by recording the ratio of Larmor frequencies in the presence of a constant magnetic field. This represents the most precise single measurement of g{sub F}{sup (87)}/g{sub F}{sup (85)} without correcting for systematic effects.

  8. Uniform coating of high aspect ratio surfaces through atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Nolan, Mark; Povey, Ian; Elliot, Simon; Cordero, Nicolas; Pemble, Martyn; Shortt, Brian; Bavdaz, Marcos

    2012-09-01

    Innovative X-ray ray imaging optic technologies, Silicon Pore Optics for example, are often characterised by large length to pore diameter aspect ratios. Such ratios present challenges to the deposition of reflectivity enhancing metallic coatings onto the mirror substrate surfaces. The technique of Atomic Layer Deposition (ALD) is perfectly suited to addressing this challenge due to the inherent self-limiting nature of the process which yields highly uniform coatings with surface roughness compatible with the requirements of high resolution X-ray imaging. We describe the results of a project aimed at developing an optimised ALD reactor and process to coat the internal wall surfaces of high aspect ratio samples with a uniform and smooth metallic layer. For sample substrates of aspect ratio ~100 the reactor has realised an average gradient of 1nm in the thickness of an Al2O3 coating on the internal walls of a 76 mm long glass tube.

  9. Superconductivity, cohesive energy density, and electron-atom ratio in metals

    NASA Technical Reports Server (NTRS)

    England, C.; Lawson, D. D.; Hrubes, J. D.

    1981-01-01

    It is shown that superconductivity above 8 K occurs in alloys and metallic compounds within relatively narrow regions of cohesive energy density with a sharp peak which includes Nb3Ge, SiV3, Nb3Ga, and NbN. When cross-correlated with the electron-atom ratio, high-temperature superconductivity can be observed in only a few regions. This suggests a search for superconductors with high-transition temperatures and critical fields within these regions.

  10. Chernobyl fallout and cancer incidence in Finland.

    PubMed

    Auvinen, Anssi; Seppä, Karri; Pasanen, Kari; Kurttio, Päivi; Patama, Toni; Pukkala, Eero; Heinävaara, Sirpa; Arvela, Hannu; Verkasalo, Pia; Hakulinen, Timo

    2014-05-01

    Twenty-five years have passed since the Chernobyl accident, but its health consequences remain to be well established. Finland was one of the most heavily affected countries by the radioactive fallout outside the former Soviet Union. We analyzed the relation of the estimated external radiation exposure from the fallout to cancer incidence in Finland in 1988-2007. The study cohort comprised all ∼ 3.8 million Finns who had lived in the same dwelling for 12 months following the accident (May 1986-April 1987). Radiation exposure was estimated using data from an extensive mobile dose rate survey. Cancer incidence data were obtained for the cohort divided into four exposure categories (the lowest with the first-year committed dose <0.1 mSv and the highest ≥ 0.5 mSv) allowing for a latency of 5 years for leukemia and thyroid cancer, and 10 years for other cancers. Of the eight predefined cancer sites regarded as radiation-related from earlier studies, only colon cancer among women showed an association with exposure from fallout [excess rate ratio per increment in exposure category 0.06, 95% confidence interval (CI) 0.02-0.11]. No such effect was observed for men, or other cancer sites. Our analysis of a large cohort over two decades did not reveal an increase in cancer incidence following the Chernobyl accident, with the possible exception of colon cancer among women. The largely null findings are consistent with extrapolation from previous studies suggesting that the effect is likely to remain too small to be empirically detectable and of little public health impact.

  11. Chernobyl fallout on Alpine glaciers

    SciTech Connect

    Ambach, W.; Rehwald, W.; Blumthaler, M.; Eisner, H.; Brunner, P.

    1989-01-01

    Measurements of the gross beta activity of snow samples from four Alpine glaciers contaminated by radioactive fallout from the Chernobyl nuclear accident and a gamma-spectrum analysis of selected samples are reported. The results are discussed with respect to possible risks to the population from using meltwater from these glaciers as drinking water.

  12. New Trends in Fallout Protection.

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    The objective of the national fallout shelter program is to provide shelter space for all Americans by--(1) locating, marking, and stocking suitable public shelter areas in existing buildings, and (2) having new structures designed and built to maximize protection. This nation's architects and engineers are now knowledgeable in radiation shielding…

  13. New Buildings with Fallout Protection.

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    Fallout protection can be built into a building with little or no additional expense, using areas that are in continuous use in the normal functioning of the building. A general discussion of principles of shelter design is given along with photographs, descriptions, drawings, and cost analysis for a large number of recently constructed buildings…

  14. Schools Built with Fallout Shelter.

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    Fallout protection can be built into a school building with little or no additional cost, using areas that are in continual use in the normal functioning of the building. A general discussion of the principles of shelter design is given along with photographs, descriptions, drawings, and cost analysis for a number of recently constructed schools…

  15. Measurement of fallout radionuclides, (239)(,240)Pu and (137)Cs, in soil and creek sediment: Sydney Basin, Australia.

    PubMed

    Smith, B S; Child, D P; Fierro, D; Harrison, J J; Heijnis, H; Hotchkis, M A C; Johansen, M P; Marx, S; Payne, T E; Zawadzki, A

    2016-01-01

    Soil and sediment samples from the Sydney basin were measured to ascertain fallout radionuclide activity concentrations and atom ratios. Caesium-137 ((137)Cs) was measured using gamma spectroscopy, and plutonium isotopes ((239)Pu and (240)Pu) were quantified using accelerator mass spectrometry (AMS). Fallout radionuclide activity concentrations were variable ranging from 0.6 to 26.1 Bq/kg for (137)Cs and 0.02-0.52 Bq/kg for (239+240)Pu. Radionuclides in creek sediment samples were an order of magnitude lower than in soils. (137)Cs and (239+240)Pu activity concentration in soils were well correlated (r(2) = 0.80) although some deviation was observed in samples collected at higher elevations. Soil ratios of (137)Cs/(239+240)Pu (decay corrected to 1/1/2014) ranged from 11.5 to 52.1 (average = 37.0 ± 12.4) and showed more variability than previous studies. (240)Pu/(239)Pu atom ratios ranged from 0.117 to 0.165 with an average of 0.146 (±0.013) and an error weighted mean of 0.138 (±0.001). These ratios are lower than a previously reported ratio for Sydney, and lower than the global average. However, these ratios are similar to those reported for other sites within Australia that are located away from former weapons testing sites and indicate that atom ratio measurements from other parts of the world are unlikely to be applicable to the Australian context.

  16. Temporal variability of beryllium-7 fallout in southwest UK.

    PubMed

    Taylor, A; Keith-Roach, M J; Iurian, A R; Mabit, L; Blake, W H

    2016-08-01

    Cosmogenic beryllium-7 has been widely employed as a sediment tracing tool and continued development of its use as a soil erosion tracer requires knowledge of fallout temporal dynamics. Data regarding beryllium-7 fallout in the UK are scarce and here the authors provide a record of beryllium-7 fallout in southwest England spanning a two-year period. A monthly fallout record was developed for Plymouth, UK using regular rainfall sampling to determine beryllium-7 rainfall activity concentration (Bq L(-1)) and deposition flux (Bq m(-2)). Data showed a general tendency for higher activity during the spring/summer months and lower activity in the autumn/winter months. Comparison with data for other UK sites (Chilton and Aberporth) for the same period found significant differences in (7)Be activity in rainwater and lower variability in Plymouth than Chilton and Aberporth. Total deposition was largely controlled by rainfall in Plymouth although regression coefficients suggested greater importance of other atmospheric controls at the Chilton and Aberporth sites. Use of a deposition proportion to rainfall proportion ratio identified periods when deposition was influenced by varying (7)Be activity in rainfall. Broad ranges in ratios were found for Chilton and Aberporth and this has implications for sediment tracer studies requiring estimates of (7)Be deposition flux across months or seasons.

  17. Absolute Isotopic Abundance Ratios and Atomic Weight of a Reference Sample of Nickel

    PubMed Central

    Gramlich, J. W.; Machlan, L. A.; Barnes, I. L.; Paulsen, P. J.

    1989-01-01

    Absolute values have been obtained for the isotopic abundance ratios of a reference sample of nickel (Standard Reference Material 986), using thermal ionization mass spectrometry. Samples of known isotopic composition, prepared from nearly isotopically pure separated nickel isotopes, were used to calibrate the mass spectrometers. The resulting absolute isotopic ratios are: 58Ni/60Ni=2.596061±0.000728, 61Ni/60Ni=0.043469±0.000015,62Ni/60Ni=0.138600±0.000045, and 64Ni/60Ni=0.035295±0.000024, which yield atom percents of 58Ni=68.076886 ±0.005919, 60Ni = 26.223146±0.005144,61Ni=1.139894±0.000433, 62Ni =3.634528±0.001142, and 64Ni =0.925546±0.000599. The atomic weight calculated from this isotopic composition is 58.693353 ±0.000147. The indicated uncertainties are overall limits of error based on two standard deviations of the mean and allowances for the effects of known sources of possible systematic error. PMID:28053421

  18. Detailed Numerical Simulation of Liquid Jet In Crossflow Atomization with High Density Ratios

    NASA Astrophysics Data System (ADS)

    Ghods, Sina

    The atomization of a liquid jet by a high speed cross-flowing gas has many applications such as gas turbines and augmentors. The mechanisms by which the liquid jet initially breaks up, however, are not well understood. Experimental studies suggest the dependence of spray properties on operating conditions and nozzle geom- etry. Detailed numerical simulations can offer better understanding of the underlying physical mechanisms that lead to the breakup of the injected liquid jet. In this work, detailed numerical simulation results of turbulent liquid jets injected into turbulent gaseous cross flows for different density ratios is presented. A finite volume, balanced force fractional step flow solver to solve the Navier-Stokes equations is employed and coupled to a Refined Level Set Grid method to follow the phase interface. To enable the simulation of atomization of high density ratio fluids, we ensure discrete consistency between the solution of the conservative momentum equation and the level set based continuity equation by employing the Consistent Rescaled Momentum Transport (CRMT) method. The impact of different inflow jet boundary conditions on different jet properties including jet penetration is analyzed and results are compared to those obtained experimentally by Brown & McDonell(2006). In addition, instability analysis is performed to find the most dominant insta- bility mechanism that causes the liquid jet to breakup. Linear instability analysis is achieved using linear theories for Rayleigh-Taylor and Kelvin- Helmholtz instabilities and non-linear analysis is performed using our flow solver with different inflow jet boundary conditions.

  19. Plasma-assisted atomic layer deposition of conformal Pt films in high aspect ratio trenches.

    PubMed

    Erkens, I J M; Verheijen, M A; Knoops, H C M; Keuning, W; Roozeboom, F; Kessels, W M M

    2017-02-07

    To date, conventional thermal atomic layer deposition (ALD) has been the method of choice to deposit high-quality Pt thin films grown typically from (MeCp)PtMe3 vapor and O2 gas at 300 °C. Plasma-assisted ALD of Pt using O2 plasma can offer several advantages over thermal ALD, such as faster nucleation and deposition at lower temperatures. In this work, it is demonstrated that plasma-assisted ALD at 300 °C also allows for the deposition of highly conformal Pt films in trenches with high aspect ratio ranging from 3 to 34. Scanning electron microscopy inspection revealed that the conformality of the deposited Pt films was 100% in trenches with aspect ratio (AR) up to 34. These results were corroborated by high-precision layer thickness measurements by transmission electron microscopy for trenches with an aspect ratio of 22. The role of the surface recombination of O-radicals and the contribution of thermal ALD reactions is discussed.

  20. Uranium Isotopic Ratio Measurements of U3O8 Reference Materials by Atom Probe Tomography

    SciTech Connect

    Fahey, Albert J.; Perea, Daniel E.; Bartrand, Jonah AG; Arey, Bruce W.; Thevuthasan, Suntharampillai

    2016-01-01

    We report results of measurements of isotopic ratios obtained with atom probe tomography on U3O8 reference materials certified for their isotopic abundances of uranium. The results show good agreement with the certified values. High backgrounds due to tails from adjacent peaks complicate the measurement of the integrated peak areas as well as the fact that only oxides of uranium appear in the spectrum, the most intense of which is doubly charged. In addition, lack of knowledge of other instrumental parameters, such as the dead time, may bias the results. Isotopic ratio measurements can be performed at the nanometer-scale with the expectation of sensible results. The abundance sensitivity and mass resolving power of the mass spectrometer are not sufficient to compete with magnetic-sector instruments but are not far from measurements made by ToF-SIMS of other isotopic systems. The agreement of the major isotope ratios is more than sufficient to distinguish most anthropogenic compositions from natural.

  1. Plasma-assisted atomic layer deposition of conformal Pt films in high aspect ratio trenches

    NASA Astrophysics Data System (ADS)

    Erkens, I. J. M.; Verheijen, M. A.; Knoops, H. C. M.; Keuning, W.; Roozeboom, F.; Kessels, W. M. M.

    2017-02-01

    To date, conventional thermal atomic layer deposition (ALD) has been the method of choice to deposit high-quality Pt thin films grown typically from (MeCp)PtMe3 vapor and O2 gas at 300 °C. Plasma-assisted ALD of Pt using O2 plasma can offer several advantages over thermal ALD, such as faster nucleation and deposition at lower temperatures. In this work, it is demonstrated that plasma-assisted ALD at 300 °C also allows for the deposition of highly conformal Pt films in trenches with high aspect ratio ranging from 3 to 34. Scanning electron microscopy inspection revealed that the conformality of the deposited Pt films was 100% in trenches with aspect ratio (AR) up to 34. These results were corroborated by high-precision layer thickness measurements by transmission electron microscopy for trenches with an aspect ratio of 22. The role of the surface recombination of O-radicals and the contribution of thermal ALD reactions is discussed.

  2. Fukushima fallout at Milano, Italy.

    PubMed

    Ioannidou, Alexandra; Manenti, Simone; Gini, Luigi; Groppi, Flavia

    2012-12-01

    The radionuclides (131)I, (137)Cs and (134)Cs were observed in the Milano region (45°) of Italy early after the nuclear accident in Fukushima, Japan. Increased atmospheric radioactivity was observed on an air filter taken on 30 March 2011, while the maximum activity of 467 μBq m(-3) for (131)I was recorded at April 3-4, 2011. The first evidence of Fukushima fallout was confirmed with (131)I and (137)Cs measured in precipitation at two sampling sites at Milano on 28 March, 2011, with the concentrations of (131)I and (137)Cs in the rainwater equal to 0.89 Bq L(-1) and 0.12 Bq L(-1), respectively. A sample of dry deposition that was collected 9 days after the first rainfall event of 27-28 March, 2011 showed that the dry deposition was more effective in the case of (137)Cs than it was for (131)I, probably because iodine was mainly in gaseous form whereas caesium was rapidly bound to aerosols and thus highly subject to dry deposition. The relatively high observed values of (137)Cs in grass, soil and fresh goat and cow milk samples were probably from Chernobyl fallout and global fallout from past nuclear tests rather than from the Fukushima accident. Finally, a dose assessment for the region of investigation showed clearly that the detected activities in all environmental samples were very far below levels of concern.

  3. Vertical distribution and migration of global fallout Pu in forest soils in southwestern China.

    PubMed

    Bu, Wenting; Zheng, Jian; Guo, Qiuju; Uchida, Shigeo

    2014-10-01

    Soil samples collected in southwestern China were analyzed for Pu isotopes. The (240)Pu/(239)Pu atom ratios were around 0.18, which indicated the dominant source of global fallout. Consistent sub-surface maximums followed by exponential decline of (239+240)Pu activities in the soil cores were observed. Most of the Pu has still remained in the 0-10 cm layers since its deposition. Convection velocities and dispersion coefficients for Pu migration in the soils were estimated by the convection-dispersion equation (CDE) model. The effective convection velocities and effective dispersion coefficients ranged from 0.05 to 0.11 cm/y and from 0.06 to 0.29 cm(2)/y, respectively. Other factors that control the vertical migration of Pu in soil besides precipitation, soil particle size distribution and organic matter were suggested. Long-term migration behaviors of Pu in the soils were simulated. The results provide the Pu background baseline for further environmental monitoring and source identification of non-global fallout Pu inputs in the future.

  4. Large-area thermoelectric high-aspect-ratio nanostructures by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Ruoho, Mikko; Juntunen, Taneli; Tittonen, Ilkka

    2016-09-01

    We report on the thermoelectric properties of large-area high-aspect-ratio nanostructures. We fabricate the structures by atomic layer deposition of conformal ZnO thin films on track-etched polycarbonate substrate. The resulting structure consists of ZnO tubules which continue through the full thickness of the substrate. The electrical and thermal properties of the structures are studied both in-plane and out-of-plane. They exhibit very low out-of-plane thermal conductivity down to 0.15 W m-1 K-1 while the in-plane sheet resistance of the films was found to be half that of the same film on glass substrate, allowing material-independent doubling of output power of any planar thin-film thermoelectric generator. The wall thickness of the fabricated nanotubes was varied within a range of up to 100 nm. The samples show polycrystalline nature with (002) preferred crystal orientation.

  5. Noise reduction and signal-to-noise ratio improvement of atomic magnetometers with optical gradiometer configurations.

    PubMed

    Kamada, Keigo; Ito, Yosuke; Ichihara, Sunao; Mizutani, Natsuhiko; Kobayashi, Tetsuo

    2015-03-09

    In the field of biomagnetic measurement, optically-pumped atomic magnetometers (OPAMs) have attracted significant attention. With the improvement of signal response and the reduction of sensor noise, the sensitivity of OPAMs is limited mainly by environmental magnetic noise. To reduce this magnetic noise, we developed the optical gradiometer, in which the differential output of two distinct measurement areas inside a glass cell was obtained directly via the magneto-optical rotation of one probe beam. When operating in appropriate conditions, the sensitivity was improved by the differential measurement of the optical gradiometer. In addition, measurements of the pseudo-magnetic noise and signal showed the improvement of the signal-to-noise ratio. These results demonstrate the feasibility of our optical gradiometer as an efficient method for reducing the magnetic noise.

  6. Mechanisms of atomic layer deposition on substrates with ultrahigh aspect ratios.

    PubMed

    Kucheyev, S O; Biener, J; Baumann, T F; Wang, Y M; Hamza, A V; Li, Z; Lee, D K; Gordon, R G

    2008-02-05

    Atomic layer deposition (ALD) appears to be uniquely suited for coating substrates with ultrahigh aspect ratios (> or similar 10(3)), including nanoporous solids. Here, we study the ALD of Cu and Cu3N on the inner surfaces of low-density nanoporous silica aerogel monoliths. Results show that Cu depth profiles in nanoporous monoliths are limited not only by Knudsen diffusion of heavier precursor molecules into the pores, as currently believed, but also by other processes such as the interaction of precursor and reaction product molecules with pore walls. Similar behavior has also been observed for Fe, Ru, and Pt ALD on aerogels. On the basis of these results, we discuss design rules for ALD precursors specifically geared for coating nanoporous solids.

  7. The enrichment ratio of atomic contacts in crystals, an indicator derived from the Hirshfeld surface analysis.

    PubMed

    Jelsch, Christian; Ejsmont, Krzysztof; Huder, Loïc

    2014-03-01

    The partitioning of space with Hirshfeld surfaces enables the analysis of fingerprint molecular interactions in crystalline environments. This study uses the decomposition of the crystal contact surface between pairs of interacting chemical species to derive an enrichment ratio. This quantity enables the analysis of the propensity of chemical species to form intermolecular interactions with themselves and other species. The enrichment ratio is obtained by comparing the actual contacts in the crystal with those computed as if all types of contacts had the same probability to form. The enrichments and contact tendencies were analyzed in several families of compounds, based on chemical composition and aromatic character. As expected, the polar contacts of the type H⋯N, H⋯O and H⋯S, which are generally hydrogen bonds, show enrichment values larger than unity. O⋯O and N⋯N contacts are impoverished while H⋯H interactions display enrichment ratios which are generally close to unity or slightly lower. In aromatic compounds, C⋯C contacts can display large enrichment ratios due to extensive π⋯π stacking in the crystal packings of heterocyclic compounds. C⋯C contacts are, however, less enriched in pure (C,H) hydrocarbons as π⋯π stacking is not so favourable from the electrostatic point of view compared with heterocycles. C⋯H contacts are favoured in (C,H) aromatics, but these interactions occur less in compounds containing O, N or S as some H atoms are then involved in hydrogen bonds. The study also highlights the fact that hydrogen is a prefered interaction partner for fluorine.

  8. Long-range tropospheric transport of uranium and plutonium weapons fallout from Semipalatinsk nuclear test site to Norway.

    PubMed

    Wendel, Cato Christian; Fifield, L Keith; Oughton, Deborah H; Lind, Ole Christian; Skipperud, Lindis; Bartnicki, Jerzy; Tims, Stephen G; Høibråten, Steinar; Salbu, Brit

    2013-09-01

    A combination of state-of-the-art isotopic fingerprinting techniques and atmospheric transport modelling using real-time historical meteorological data has been used to demonstrate direct tropospheric transport of radioactive debris from specific nuclear detonations at the Semipalatinsk test site in Kazakhstan to Norway via large areas of Europe. A selection of archived air filters collected at ground level at 9 stations in Norway during the most intensive atmospheric nuclear weapon testing periods (1957-1958 and 1961-1962) has been screened for radioactive particles and analysed with respect to the concentrations and atom ratios of plutonium (Pu) and uranium (U) using accelerator mass spectrometry (AMS). Digital autoradiography screening demonstrated the presence of radioactive particles in the filters. Concentrations of (236)U (0.17-23nBqm(-3)) and (239+240)Pu (1.3-782μBqm(-3)) as well as the atom ratios (240)Pu/(239)Pu (0.0517-0.237) and (236)U/(239)Pu (0.0188-0.7) varied widely indicating several different sources. Filter samples from autumn and winter tended to have lower atom ratios than those sampled in spring and summer, and this likely reflects a tropospheric influence in months with little stratospheric fallout. Very high (236)U, (239+240)Pu and gross beta activity concentrations as well as low (240)Pu/(239)Pu (0.0517-0.077), (241)Pu/(239)Pu (0.00025-0.00062) and (236)U/(239)Pu (0.0188-0.046) atom ratios, characteristic of close-in and tropospheric fallout, were observed in filters collected at all stations in Nov 1962, 7-12days after three low-yield detonations at Semipalatinsk (Kazakhstan). Atmospheric transport modelling (NOAA HYSPLIT_4) using real-time meteorological data confirmed that long range transport of radionuclides, and possibly radioactive particles, from Semipalatinsk to Norway during this period was plausible. The present work shows that direct tropospheric transport of fallout from atmospheric nuclear detonations periodically may have

  9. Fallout forecasting: 1945-1962

    SciTech Connect

    Kennedy, W.R. Jr.

    1986-03-01

    The delayed hazards of fallout from the detonations of nuclear devices in the atmosphere have always been the concern of those involved in the Test Program. Even before the Trinity Shot (TR-2) of July 16, 1945, many very competent, intelligent scientists and others from all fields of expertise tried their hand at the prediction problems. This resume and collection of parts from reports, memoranda, references, etc., endeavor to chronologically outline prediction methods used operationally in the field during Test Operations of nuclear devices fired into the atmosphere.

  10. DUAL USE OF SCHOOL FALLOUT SHELTER SPACE.

    ERIC Educational Resources Information Center

    SAYERS, JOHN

    THIS REPORT DISCUSSES CONSIDERATIONS IN THE USE OF FALLOUT SHELTER SPACE FOR NORMAL SCHOOL ACTIVITIES, INCLUDING THE REQUIREMENTS FOR FALLOUT SHELTERS AND PROBLEMS RELATED TO WINDOWLESS ROOMS. THE PRESENT LACK OF INFORMATION ABOUT PSYCHOLOGICAL PROBLEMS RELATED TO WINDOWLESS ROOMS IS MENTIONED. THE BEST USES FOR WINDOWLESS SPACE ARE NOTED--(1)…

  11. A new ground-level fallout record of uranium and plutonium isotopes for northern temperate latitudes

    NASA Astrophysics Data System (ADS)

    Warneke, Thorsten; Croudace, Ian W.; Warwick, Phillip E.; Taylor, Rex N.

    2002-11-01

    Plutonium and uranium isotope ratios can be used to differentiate the sources of nuclear contamination from nuclear weapon establishments (Environ. Sci. Technol. 34 (2000) 4496; Internal Report for AWRE Aldermaston, UK (1961)), weapon fallout (Geochim. Cosmochim. Acta 51 (1987) 2623; Earth Planet. Sci. Lett. 63 (1983) 202; Earth Planet. Sci. Lett. 22 (1974) 111; Geochim. Cosmochim. Acta 64 (2000) 989), reprocessing plants, reactor or satellite accidents (Science 105 (1979) 583; Science 238 (1987) 512) and in addition they provide markers for post-1952 geochronology of environmental systems. A good record of plutonium and uranium isotope ratios of the background resulting from atmospheric nuclear testing is essential for source characterisation studies. Using recently developed mass spectrometric techniques (J. Anal. At. Spectrom. 16 (2001) 279) we present here the first complete records between 1952 and the present day of northern temperate latitude 240Pu/ 239Pu and 238U/ 235U atom ratios for atmospheric deposition. Such information was not derived directly during the period of atmospheric testing because suitable mass spectrometric capability was not available. The currently derived records are based on an annual herbage archive and a core from an Alpine glacier. These studies reveal hitherto unseen fluctuations in the 238U/ 235U atmospheric fallout record, some of which are directly related to nuclear testing. In addition, they also provide the first evidence that plutonium contamination originating from Nevada Desert atmospheric weapon tests in 1952 and 1953 extended eastwards as far as northwestern Europe. The results presented here demonstrate that we now have the capability to detect and precisely identify sources of plutonium in the environment with implications for the development of atmospheric transport models, recent geochronology and environmental studies.

  12. Particle fallout/activity sensor

    NASA Technical Reports Server (NTRS)

    Curtis, Ihlefeld M. (Inventor); Youngquist, Robert C. (Inventor); Moerk, John S. (Inventor); Rose, Kenneth A., III (Inventor)

    1995-01-01

    A particle fallout/activity sensor measures relative amounts of dust or other particles which collect on a mirror in an area to be monitored. The sensor includes a sensor module and a data acquisition module, both of which can be operated independently of one another or in combination with one another. The sensor module includes a housing containing the mirror, an LED assembly for illuminating the mirror and an optical detector assembly for detecting light scattered off of the mirror by dust or other particles collected thereon. A microprocessor controls operation of the sensor module's components and displays results of a measurement on an LCD display mounted on the housing. A push button switch is also mounted on the housing which permits manual initiation of a measurement. The housing is constructed of light absorbing material, such as black delrin, which minimizes detection of light by the optical detector assembly other than that scattered by dust or particles on the mirror. The data acquisition module can be connected to the sensor module and includes its own microprocessor, a timekeeper and other digital circuitry for causing the sensor module to make a measurement periodically and send the measurement data to the data acquisition module for display and storage in memory for later retrieval and transfer to a separate computer. The time tagged measurement data can also be used to determine the relative level of activity in the monitored area since this level is directly related to the amount of dust or particle fallout in the area.

  13. Atomic Layer Deposition for Coating of High Aspect Ratio TiO2 Nanotube Layers

    PubMed Central

    2016-01-01

    We present an optimized approach for the deposition of Al2O3 (as a model secondary material) coating into high aspect ratio (≈180) anodic TiO2 nanotube layers using the atomic layer deposition (ALD) process. In order to study the influence of the diffusion of the Al2O3 precursors on the resulting coating thickness, ALD processes with different exposure times (i.e., 0.5, 2, 5, and 10 s) of the trimethylaluminum (TMA) precursor were performed. Uniform coating of the nanotube interiors was achieved with longer exposure times (5 and 10 s), as verified by detailed scanning electron microscopy analysis. Quartz crystal microbalance measurements were used to monitor the deposition process and its particular features due to the tube diameter gradient. Finally, theoretical calculations were performed to calculate the minimum precursor exposure time to attain uniform coating. Theoretical values on the diffusion regime matched with the experimental results and helped to obtain valuable information for further optimization of ALD coating processes. The presented approach provides a straightforward solution toward the development of many novel devices, based on a high surface area interface between TiO2 nanotubes and a secondary material (such as Al2O3). PMID:27643411

  14. High aspect ratio iridescent three-dimensional metal–insulator–metal capacitors using atomic layer deposition

    SciTech Connect

    Burke, Micheal Blake, Alan; Djara, Vladimir; O'Connell, Dan; Povey, Ian M.; Cherkaoui, Karim; Monaghan, Scott; Scully, Jim; Murphy, Richard; Hurley, Paul K.; Pemble, Martyn E.; Quinn, Aidan J.

    2015-01-01

    The authors report on the structural and electrical properties of TiN/Al{sub 2}O{sub 3}/TiN metal–insulator–metal (MIM) capacitor structures in submicron three-dimensional (3D) trench geometries with an aspect ratio of ∼30. A simplified process route was employed where the three layers for the MIM stack were deposited using atomic layer deposition (ALD) in a single run at a process temperature of 250 °C. The TiN top and bottom electrodes were deposited via plasma-enhanced ALD using a tetrakis(dimethylamino)titanium precursor. 3D trench devices yielded capacitance densities of 36 fF/μm{sup 2} and quality factors >65 at low frequency (200 Hz), with low leakage current densities (<3 nA/cm{sup 2} at 1 V). These devices also show strong optical iridescence which, when combined with the covert embedded capacitance, show potential for system in package (SiP) anticounterfeiting applications.

  15. Atomic Layer Deposition for Coating of High Aspect Ratio TiO2 Nanotube Layers.

    PubMed

    Zazpe, Raul; Knaut, Martin; Sopha, Hanna; Hromadko, Ludek; Albert, Matthias; Prikryl, Jan; Gärtnerová, V; Bartha, Johann W; Macak, Jan M

    2016-10-05

    We present an optimized approach for the deposition of Al2O3 (as a model secondary material) coating into high aspect ratio (≈180) anodic TiO2 nanotube layers using the atomic layer deposition (ALD) process. In order to study the influence of the diffusion of the Al2O3 precursors on the resulting coating thickness, ALD processes with different exposure times (i.e., 0.5, 2, 5, and 10 s) of the trimethylaluminum (TMA) precursor were performed. Uniform coating of the nanotube interiors was achieved with longer exposure times (5 and 10 s), as verified by detailed scanning electron microscopy analysis. Quartz crystal microbalance measurements were used to monitor the deposition process and its particular features due to the tube diameter gradient. Finally, theoretical calculations were performed to calculate the minimum precursor exposure time to attain uniform coating. Theoretical values on the diffusion regime matched with the experimental results and helped to obtain valuable information for further optimization of ALD coating processes. The presented approach provides a straightforward solution toward the development of many novel devices, based on a high surface area interface between TiO2 nanotubes and a secondary material (such as Al2O3).

  16. Formulation of probabilistic models of protein structure in atomic detail using the reference ratio method.

    PubMed

    Valentin, Jan B; Andreetta, Christian; Boomsma, Wouter; Bottaro, Sandro; Ferkinghoff-Borg, Jesper; Frellsen, Jes; Mardia, Kanti V; Tian, Pengfei; Hamelryck, Thomas

    2014-02-01

    We propose a method to formulate probabilistic models of protein structure in atomic detail, for a given amino acid sequence, based on Bayesian principles, while retaining a close link to physics. We start from two previously developed probabilistic models of protein structure on a local length scale, which concern the dihedral angles in main chain and side chains, respectively. Conceptually, this constitutes a probabilistic and continuous alternative to the use of discrete fragment and rotamer libraries. The local model is combined with a nonlocal model that involves a small number of energy terms according to a physical force field, and some information on the overall secondary structure content. In this initial study we focus on the formulation of the joint model and the evaluation of the use of an energy vector as a descriptor of a protein's nonlocal structure; hence, we derive the parameters of the nonlocal model from the native structure without loss of generality. The local and nonlocal models are combined using the reference ratio method, which is a well-justified probabilistic construction. For evaluation, we use the resulting joint models to predict the structure of four proteins. The results indicate that the proposed method and the probabilistic models show considerable promise for probabilistic protein structure prediction and related applications.

  17. Ratio

    NASA Astrophysics Data System (ADS)

    Webster, Nathan A. S.; Pownceby, Mark I.; Madsen, Ian C.; Studer, Andrew J.; Manuel, James R.; Kimpton, Justin A.

    2014-12-01

    Effects of basicity, B (CaO:SiO2 ratio) on the thermal range, concentration, and formation mechanisms of silico-ferrite of calcium and aluminum (SFCA) and SFCA-I iron ore sinter bonding phases have been investigated using an in situ synchrotron X-ray diffraction-based methodology with subsequent Rietveld refinement-based quantitative phase analysis. SFCA and SFCA-I phases are the key bonding materials in iron ore sinter, and improved understanding of the effects of processing parameters such as basicity on their formation and decomposition may assist in improving efficiency of industrial iron ore sintering operations. Increasing basicity significantly increased the thermal range of SFCA-I, from 1363 K to 1533 K (1090 °C to 1260 °C) for a mixture with B = 2.48, to ~1339 K to 1535 K (1066 °C to 1262 °C) for a mixture with B = 3.96, and to ~1323 K to 1593 K (1050 °C to 1320 °C) at B = 4.94. Increasing basicity also increased the amount of SFCA-I formed, from 18 wt pct for the mixture with B = 2.48 to 25 wt pct for the B = 4.94 mixture. Higher basicity of the starting sinter mixture will, therefore, increase the amount of SFCA-I, considered to be more desirable of the two phases. Basicity did not appear to significantly influence the formation mechanism of SFCA-I. It did, however, affect the formation mechanism of SFCA, with the decomposition of SFCA-I coinciding with the formation of a significant amount of additional SFCA in the B = 2.48 and 3.96 mixtures but only a minor amount in the highest basicity mixture. In situ neutron diffraction enabled characterization of the behavior of magnetite after melting of SFCA produced a magnetite plus melt phase assemblage.

  18. Atomic Theory and Multiple Combining Proportions: The Search for Whole Number Ratios.

    PubMed

    Usselman, Melvyn C; Brown, Todd A

    2015-04-01

    John Dalton's atomic theory, with its postulate of compound formation through atom-to-atom combination, brought a new perspective to weight relationships in chemical reactions. A presumed one-to-one combination of atoms A and B to form a simple compound AB allowed Dalton to construct his first table of relative atomic weights from literature analyses of appropriate binary compounds. For such simple binary compounds, the atomic theory had little advantages over affinity theory as an explanation of fixed proportions by weight. For ternary compounds of the form AB2, however, atomic theory made quantitative predictions that were not deducible from affinity theory. Atomic theory required that the weight of B in the compound AB2 be exactly twice that in the compound AB. Dalton, Thomas Thomson and William Hyde Wollaston all published within a few years of each other experimental data that claimed to give the predicted results with the required accuracy. There are nonetheless several experimental barriers to obtaining the desired integral multiple proportions. In this paper I will discuss replication experiments which demonstrate that only Wollaston's results are experimentally reliable. It is likely that such replicability explains why Wollaston's experiments were so influential.

  19. Review of current nuclear fallout codes.

    PubMed

    Auxier, Jerrad P; Auxier, John D; Hall, Howard L

    2017-05-01

    The importance of developing a robust nuclear forensics program to combat the illicit use of nuclear material that may be used as an improvised nuclear device is widely accepted. In order to decrease the threat to public safety and improve governmental response, government agencies have developed fallout-analysis codes to predict the fallout particle size, dose, and dispersion and dispersion following a detonation. This paper will review the different codes that have been developed for predicting fallout from both chemical and nuclear weapons. This will decrease the response time required for the government to respond to the event.

  20. Unexpected Huge Dimerization Ratio in One-Dimensional Carbon Atomic Chains.

    PubMed

    Lin, Yung-Chang; Morishita, Shigeyuki; Koshino, Masanori; Yeh, Chao-Hui; Teng, Po-Yuan; Chiu, Po-Wen; Sawada, Hidetaka; Suenaga, Kazutomo

    2017-01-11

    Peierls theory predicted atomic distortion in one-dimensional (1D) crystal due to its intrinsic instability in 1930. Free-standing carbon atomic chains created in situ in transmission electron microscope (TEM)1-3 are an ideal example to experimentally observe the dimerization behavior of carbon atomic chain within a finite length. We report here a surprisingly huge distortion found in the free-standing carbon atomic chains at 773 K, which is 10 times larger than the value expected in the system. Such an abnormally distorted phase only dominates at the elevated temperatures, while two distinct phases, distorted and undistorted, coexist at lower or ambient temperatures. Atom-by-atom spectroscopy indeed shows considerable variations in the carbon 1s spectra at each atomic site but commonly observes a slightly downshifted π* peak, which proves its sp(1) bonding feature. These results suggest that the simple model, relaxed and straight, is not fully adequate to describe the realistic 1D structure, which is extremely sensitive to perturbations such as external force or boundary conditions.

  1. Fallout Computer Codes. A Bibliographic Perspective

    DTIC Science & Technology

    1994-07-01

    of time. The model calculates g(t) by assuming that fallout descends from a nuclear cloud that is characterized initially by a Gaussian distribution in...features and differences among the major radioactive fallout models and computer codes that are either in current use or that form the basis for more...contemporary codes and other computational tools. The DELFIC, WSEG-10, KDFOC2, SEER3, and DNAF-1 codes and the EM-I model are addressed. The review is

  2. World-wide fallout from nuclear weapons

    SciTech Connect

    Not Available

    1994-01-01

    This video explains what is known and what is not known by today's science about the long term consequences of world-wide fallout. In the interest of accuracy, this report is confined to the fallout on which a substantial amount of information is now available. Much has been written and said about this subject both officially and unofficially. The purpose of this film is to correct any factually unsupported statements which have been and continue to be issued from time to time.

  3. Measurements of ²³⁶U in ancient and modern peat samples and implications for postdepositional migration of fallout radionuclides.

    PubMed

    Quinto, Francesca; Hrnecek, Erich; Krachler, Michael; Shotyk, William; Steier, Peter; Winkler, Stephan R

    2013-05-21

    (236)U was analyzed in an ombrotrophic peat core representing the last 80 years of atmospheric deposition and a minerotrophic peat sample from the last interglacial period. The determination of (236)U at levels of 10(7) atoms/g was possible by using ultraclean laboratory procedures and accelerator mass spectrometry. The vertical profile of the (236)U/(238)U isotopic ratio along the ombrotrophic peat core represents the first observation of the (236)U bomb peak in a terrestrial environment. A constant level of anthropogenic (236)U with an average (236)U/(238)U isotopic ratio of (1.24 ± 0.08) × 10(-6) in the top layers of the core was observed. Comparing the abundances of the global fallout derived (236)U and (239)Pu along the peat core, the post depositional migration of plutonium clearly exceeds that of uranium. However, the cumulative (236)U/(239)Pu ratio of 0.62 ± 0.31 is in agreement with previous studies on the global fallout uranium and plutonium. In the interglacial peat samples a (236)U/(238)U isotopic ratio of (3.3 ± 0.7) × 10(-12) was detected; although this measurement is an upper limit, it constitutes a significant step forward in the experimental determination of the natural (236)U abundance and represents a true background sample for the ombrotrophic peat core.

  4. Fallout sheltering: is it feasible?

    PubMed

    Ehrlich, R; Ring, J

    1987-03-01

    The feasibility of sheltering the U.S. population from fallout resulting from a large-scale nuclear attack is assessed using a mathematical model. The model is used to calculate the reduction in cumulative dose received by a sheltered survivor, as a function of five adjustable parameters. Three time periods are postulated: time in the shelter, a transition period during which time out of the shelter increases and a final period in which half the time is spent outside the shelter. The parameters are varied independently, and the resulting dose reduction factor is compared with what seems to be necessary for survival in different regions of the country under the postulated attack. Another model developed by K.S. Gant and C.V. Chester is compared with this one. Similarities and differences are pointed out, and where possible the results of the two are checked for compatibility. An important question addressed in this paper is whether under the conditions of a large-scale nuclear attack sheltering a relatively unprepared population is at all feasible. Sensitivity tests of the various parameters in our model show that relatively low protection factor areas such as basements or inner rooms already existing in homes or other buildings could quite adequately serve as shelters for most of the area of the contiguous United States. Furthermore, continuous stays in these shelters of more than three weeks do not seem to be necessary for these large parts of the United States.

  5. Fallout sheltering: is it feasible

    SciTech Connect

    Ehrlich, R.; Ring, J.

    1987-03-01

    The feasibility of sheltering the U.S. population from fallout resulting from a large-scale nuclear attack is assessed using a mathematical model. The model is used to calculate the reduction in cumulative dose received by a sheltered survivor, as a function of five adjustable parameters. Three time periods are postulated: time in the shelter, a transition period during which time out of the shelter increases and a final period in which half the time is spent outside the shelter. The parameters are varied independently, and the resulting dose reduction factor is compared with what seems to be necessary for survival in different regions of the country under the postulated attack. Another model developed by K.S. Gant and C.V. Chester is compared with this one. Similarities and differences are pointed out, and where possible the results of the two are checked for compatibility. An important question addressed in this paper is whether under the conditions of a large-scale nuclear attack sheltering a relatively unprepared population is at all feasible. Sensitivity tests of the various parameters in our model show that relatively low protection factor areas such as basements or inner rooms already existing in homes or other buildings could quite adequately serve as shelters for most of the area of the contiguous United States. Furthermore, continuous stays in these shelters of more than three weeks do not seem to be necessary for these large parts of the United States.

  6. Photographs and Pamphlet about Nuclear Fallout. The Constitution Community: Postwar United States (1945 to Early 1970s).

    ERIC Educational Resources Information Center

    Lawlor, John M., Jr.

    In August 1945, the United States unleashed an atomic weapon against the Japanese at Hiroshima and Nagasaki and brought an end to World War II. These bombs killed in two ways -- by the blast's magnitude and resulting firestorm, and by nuclear fallout. After the Soviet Union exploded its first atom bomb in 1949, the Cold War waged between the two…

  7. Reconstruction and analysis of cesium-137 fallout deposition patterns in the Marshall Islands

    NASA Astrophysics Data System (ADS)

    Whitcomb, Robert Cleckley, Jr.

    Estimates of 137Cs deposition due to fallout originating from nuclear weapons testing in the Marshall Islands have been made for several locations in the Marshall Islands. These retrospective estimates were based primarily on historical exposure rate and gummed film measurements. The methods used to reconstruct these deposition estimates are specific for six of the Pacific tests. These methods are also similar to those used in the National Cancer Institute study for reconstructing 131I deposition from the Nevada Test Site. Reconstructed cumulative deposition estimates are validated against contemporary measurements of 137Cs concentration in soil. This validation work also includes an accounting for estimated global fallout contributions. These validations show that the overall geometric bias in predicted-to-observed (P/O) ratios is 1.0 (indicating excellent agreement). The 5th and 95th percentile range of this distribution is 0.35--2.95. The P/O ratios for estimates using historical gummed film measurements tend to slightly over-predict more than estimates using exposure rate measurements. The methods produce reasonable estimates of deposition confirming that radioactive fallout occurred at atolls further south of the four northern atolls recognized by the Department of Energy as being affected by fallout. The deposition estimate methods, supported by the very good agreement between estimates and measurements, suggest that these methods can be used for other weapons testing fallout radionuclides with confidence.

  8. Tables of stark level transition probabilities and branching ratios in hydrogen-like atoms

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1980-01-01

    The transition probabilities which are given in terms of n prime k prime and n k are tabulated. No additional summing or averaging is necessary. The electric quantum number k plays the role of the angular momentum quantum number l in the presence of an electric field. The branching ratios between stark levels are also tabulated. Necessary formulas for the transition probabilities and branching ratios are given. Symmetries are discussed and selection rules are given. Some disagreements for some branching ratios are found between the present calculation and the measurement of Mark and Wierl. The transition probability multiplied by the statistical weight of the initial state is called the static intensity J sub S, while the branching ratios are called the dynamic intensity J sub D.

  9. Prediction of spatial variation in global fallout of 137Cs using precipitation.

    PubMed

    Pálsson, S E; Howard, B J; Wright, S M

    2006-08-31

    Deposition from atmospheric nuclear weapons tests (termed global fallout) has been shown to be proportional to the rate of precipitation. Here we describe methods for using precipitation and radionuclide deposition information for a reference site to estimate global fallout at other locations. These methods have been used to estimate global fallout in Iceland, identified during the Arctic Monitoring and Assessment Programme (AMAP) by Wright et al. [Wright, S.M., Howard, B.J., Strand, P., Nylén, T., Sickel, M.A.K., 1999. Prediction of 137Cs deposition from atmospheric nuclear weapons tests within the Arctic. Environ Pollut 104, 131-143.] as one of the Arctic areas which received the highest global fallout, but where measurements of contamination were sparse, and difficult to obtain due to the remote and inaccessible terrain of much of the country. Measurements of global fallout 137Cs deposition have been made in Iceland at sites close to meteorological stations to ensure that precipitation data were of high quality. The AMAP modeling approach, based on measured precipitation and radionuclide deposition data, was applied using a reference monitoring station located close to Reykjavik. The availability of good precipitation data and locally based estimates of time dependent ratios of 137Cs deposition to precipitation during the fallout period gave a better correlation between predicted and measured 137Cs global fallout (r2=0.96) than that achieved using the much more heterogeneous set of data collected by AMAP over the whole of the Arctic. Having obtained satisfactory results with the model for a number of calibration sites alongside meteorological stations we then produced a map of estimated 137Cs deposition based on a model of estimated precipitation. This deposition map was then successfully validated (r2=0.85) for sites where 137Cs deposition was measured; the associated uncertainty in predictions was also estimated.

  10. New isotopic evidence of lead contamination in wheat grain from atmospheric fallout.

    PubMed

    Yang, Jun; Chen, Tongbin; Lei, Mei; Zhou, Xiaoyong; Huang, Qifei; Ma, Chuang; Gu, Runyao; Guo, Guanghui

    2015-10-01

    Crops could accumulate trace metals by soil-root transfer and foliar uptake from atmospheric fallout, and an accurate assessment of pollution sources is a prerequisite for preventing heavy metal pollution in agricultural products. In this study, we examined Pb isotope rates to trace the sources of Pb in wheat grain grown in suburbs. Results showed that, even in zones with scarcely any air pollution spots, atmospheric fallout was still a considerable source of Pb accumulation in wheat. The concentration of Pb in wheat grain has poor correlation with that in farm soil. The Pb concentration in wheat grains with dust in bran coat was significantly higher than that in wheat grains, which indicates that Pb may accumulate by foliar uptake. The Pb isotope rate has obvious differences between the soil and atmospheric fallout, and scatter ratio is significantly closer between the wheat grain and atmospheric fallout. Atmospheric fallout is a more significant source of Pb concentration in wheat grains than in soil. As far as we know, this is the first study on the main sources of lead in grain crop (wheat) samples with isotope. This study aims to improve our understanding of the translocation of foliar-absorbed metals to nonexposed parts of plants.

  11. Distribution of neptunium and plutonium in New Mexico lichen samples (Usnea arizonica) contaminated by atmospheric fallout

    DOE PAGES

    Oldham, Jr., Warren J.; Hanson, Susan K.; Lavelle, Kevin B.; ...

    2015-08-30

    In this study, the concentrations of 237Np, 239Pu and 240Pu were determined in lichen samples (Usnea arizonica) that were collected from ten locations in New Mexico between 2011 and 2013 using isotope dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS). The observed isotopic ratios for 237Np/239Pu and 240Pu/239Pu indicate trace contamination from global and regional fallout (e.g. Trinity test and atmospheric testing at the Nevada Test Site). The fact that actinide contamination is detected in recent lichen collections suggests continuous re-suspension of fallout radionuclides even 50 years after ratification of the Limited Test Ban Treaty.

  12. Observation of anomalous Stokes versus anti-Stokes ratio in MoTe2 atomic layers

    NASA Astrophysics Data System (ADS)

    Goldstein, Thomas; Chen, Shao-Yu; Xiao, Di; Ramasubramaniam, Ashwin; Yan, Jun

    We grow hexagonal molybdenum ditelluride (MoTe2), a prototypical transition metal dichalcogenide (TMDC) semiconductor, with chemical vapor transport methods and investigate its atomic layers with Stokes and anti-Stokes Raman scattering. We report observation of all six types of zone center optical phonons. Quite remarkably, the anti-Stokes Raman intensity of the low energy layer-breathing mode becomes more intense than the Stokes peak under certain experimental conditions, creating an illusion of 'negative temperature'. This effect is tunable, and can be switched from anti-Stokes enhancement to suppression by varying the excitation wavelength. We interpret this observation to be a result of resonance effects arising from the C excitons in the vicinity of the Brillouin zone center, which are robust even for multiple layers of MoTe2. The intense anti-Stokes Raman scattering provides a cooling channel for the crystal and opens up opportunities for laser cooling of atomically thin TMDC semiconductor devices. Supported by the University of Massachusetts Amherst, the National Science Foundation Center for Hierarchical Manufacturing (CMMI-1025020) and Office of Emerging Frontiers in Research and Innovation (EFRI-1433496).

  13. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    NASA Astrophysics Data System (ADS)

    Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.

    2011-10-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90° ( x=0.99 Å -1). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number ( Zeff) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Zeff of breast tissues, which are mainly related to the elemental composition of carbon ( Z=6) and oxygen ( Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  14. Automating the Coupling of ORIGEN with GADRAS via the Fallout Analysis Tool for National Technical Nuclear Forensics

    SciTech Connect

    Monterial, Mateusz; Jodoin, Vincent J; Lefebvre, Jordan P; Peplow, Douglas E.; Hooper, David A

    2012-01-01

    Nuclear forensic teams will be deployed to collect and evaluate fallout samples on the ground in the scenario of a low-yield nuclear detonation in a heavily populated area. Quick non-destructive methods of predicting the quality of the sample before it is analyzed in detail are essential for efficient post-event collections. In this work, the process of exporting Defense Land Fallout Interpretive Code (DELFIC) results into Gamma Detector Response and Analysis Software (GADRAS) has been automated within the Fallout Analysis Tool. This coupling allows for the simulation of detector responses to fallout samples with varying degrees of fractionation. The degree to which the samples are fractionated depends on the location of the samples in the fallout field. In the following study, this phenomenon is examined, as its understanding is important to the investigation of debris distribution. The simulated detector spectra from GADRAS can be used to compare peak ratios of volatile-refractory isotope pairs in order to determine the degree of fractionation. Simulated fractionated fallout samples from DELFIC for a 10 kt, pure 235U fission surface burst were modeled for distances ranging to 256 km out from ground zero, and for times up to 1 week from detonation. The fractionation ratios, also known as r values, from isotope concentrations, photon lines and peak areas of four volatile-refractory pairs were calculated and compared. Fractionation prediction via the peak areas method was evaluated for each pair by comparing the results with the simulated radionuclide inventory.

  15. Temporal variation of cesium isotope concentrations and atom ratios in zooplankton in the Pacific off the east coast of Japan

    NASA Astrophysics Data System (ADS)

    Ikenoue, Takahito; Takata, Hyoe; Kusakabe, Masashi; Kudo, Natsumi; Hasegawa, Kazuyuki; Ishimaru, Takashi

    2017-01-01

    After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, concentrations of cesium isotopes (133Cs, 134Cs, and 137Cs) were measured in zooplankton collected in the Pacific off the east coast of Japan from May 2012 to February 2015. The time series of the data exhibited sporadic 137Cs concentration peaks in zooplankton. In addition, the atom ratio of 137Cs/133Cs in zooplankton was consistently high compared to that in ambient seawater throughout the sampling period. These phenomena cannot be explained fully by the bioaccumulation of 137Cs in zooplankton via ambient seawater intake, the inclusion of resuspended sediment in the plankton sample, or the taxonomic composition of the plankton. Autoradiography revealed highly radioactive particles within zooplankton samples, which could be the main factor underlying the sporadic appearance of high 137Cs concentrations in zooplankton as well as the higher ratio of 137Cs/133Cs in zooplankton than in seawater.

  16. Temporal variation of cesium isotope concentrations and atom ratios in zooplankton in the Pacific off the east coast of Japan

    PubMed Central

    Ikenoue, Takahito; Takata, Hyoe; Kusakabe, Masashi; Kudo, Natsumi; Hasegawa, Kazuyuki; Ishimaru, Takashi

    2017-01-01

    After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, concentrations of cesium isotopes (133Cs, 134Cs, and 137Cs) were measured in zooplankton collected in the Pacific off the east coast of Japan from May 2012 to February 2015. The time series of the data exhibited sporadic 137Cs concentration peaks in zooplankton. In addition, the atom ratio of 137Cs/133Cs in zooplankton was consistently high compared to that in ambient seawater throughout the sampling period. These phenomena cannot be explained fully by the bioaccumulation of 137Cs in zooplankton via ambient seawater intake, the inclusion of resuspended sediment in the plankton sample, or the taxonomic composition of the plankton. Autoradiography revealed highly radioactive particles within zooplankton samples, which could be the main factor underlying the sporadic appearance of high 137Cs concentrations in zooplankton as well as the higher ratio of 137Cs/133Cs in zooplankton than in seawater. PMID:28051136

  17. Design of Schools to Incorporate Fallout Protection.

    ERIC Educational Resources Information Center

    Folley, Milo D.

    Means are suggested by which a school district may incorporate low-cost fallout protection in a school construction program, through construction of an underground shelter beneath the concrete slab foundation. Ways of controlling distribution and filtering air are discussed. The author also suggests consideration of a completely underground…

  18. Radioactive Fallout From Nuclear Weapons Testing ...

    EPA Pesticide Factsheets

    2016-05-16

    Detonating nuclear weapons above ground sends radioactive materials into the atmosphere from the ground level up to very high elevations. Overtime, these materials settle out of the atmosphere and fall to the ground. Fallout typically contains hundreds of different radionuclides. Since the end of aboveground nuclear weapons testing, radionuclides have largely decayed away.

  19. Effect of nozzle length-to-diameter ratio on atomization of turbulent liquid jets

    NASA Astrophysics Data System (ADS)

    Osta, Anu Ranjan

    Breakup of liquid jets is of considerable interest motivated by its applicability in combustion and propulsion systems (CI and SI engines), and agricultural fertilizer/pesticide sprays, among others. Almost all of the practical liquid injectors introduce some degree of turbulence in the liquid jet leaving the injector passage and an intriguing question is the relative importance of the liquid turbulence, cavitation, and the aerodynamic forces in the breakup processes of fuel injectors. A better design of liquid fuel injector would reduce pollutants and increase the efficiency of liquid fuel combustion processes. An experimental study to investigate the effect of nozzle length to diameter ratio on the surface properties of turbulent liquid jets in gaseous crossflow and still air was carried out. Straight cavitation-free nozzles with length/diameter ratios of 10, 20 and 40 were used to generate turbulent liquid jets in gaseous crossflow. The present study was limited to small Ohnesorge number liquid jets (Oh < 0.01) injected in crossflow within the shear breakup regime (WeG > 110). The diagnostics consisted of pulsed shadowgraphy, pulsed digital holographic microscopy and x-ray diagnostics. The x-ray tests were conducted at the Advanced Photon Source (APS) facility of Argonne National Laboratory. The test matrix was designed to maintain the same aerodynamic forces in order to isolate the effects of jet turbulence on the breakup process. The measurements included liquid jet surface properties, breakup location of the liquid column as a whole, the breakup regime transitions, bubble size inside the jet and seeding particle displacement inside the jet structures. The results include the jet surface characteristics, the liquid column breakup lengths, bubble growth, and phenomenological analysis to explain the observed results. It is observed that for a jet breakup in crossflow the injector passage length does play a role in determining the breakup length as well as

  20. Detection of water molecules in inert gas based plasma by the ratios of atomic spectral lines

    NASA Astrophysics Data System (ADS)

    Bernatskiy, A. V.; Ochkin, V. N.

    2017-01-01

    A new approach is considered to detect the water leaks in inert plasma-forming gas present in the reactor chamber. It is made up of the intensity ratio of D α and H α spectral lines in combination with O, Ar and Xe lines intensity. The concentrations of H2O, O, H and D particles have been measured with high sensitivity. At the D2 admixture pressure {{p}{{\\text{D}\\text{2}}}}   =  0.025 mbar, we used the acquisition time of 10 s to measure the rate of water molecules injected from the outside, Γ0  =  1.4 · 10-9 mbar · m3 · s-1, and the incoming water molecules to plasma, Γ  =  5 ·10-11 mbar · m3 · s-1. The scaling proves that at small D2 admixtures (10-4 mbar), the leaks with the rates Γ0  ≈  6 · 10-12 mbar · m3 · s-1 and Γ  ≈  2 · 10-13 mbar · m3 · s-1 can be detected and measured. The difference between Γ0 and Γ values is due to the high degree of H2O dissociation, which can be up to 97-98%.

  1. Focused ion beam-assisted fabrication of soft high-aspect ratio silicon nanowire atomic force microscopy probes.

    PubMed

    Knittel, Peter; Hibst, Nicolas; Mizaikoff, Boris; Strehle, Steffen; Kranz, Christine

    2017-03-28

    In this study, high-aspect ratio silicon nanowire (SiNW) - modified atomic force microscopy (AFM) probes are fabricated using focused ion beam (FIB) microfabrication technology and vapor-solid-solid synthesis. Commercially available soft silicon nitride probes are used for localized nanowire growth yielding soft high-aspect ratio AFM probes. The SiNW-modified cantilevers are used here for imaging in PeakForce Tappingۛ (PFT) mode, which offers high force control along with valuable information about tip-sample adhesion. A platinum catalyst, deposited accurately at a truncated AFM tip by ion beam-induced deposition (IBID), was used for localized nanowire synthesis. It could be shown that the deposition of a thin silicon dioxide layer prior to the catalyst deposition resulted in controlled SiNW growth on silicon as well as silicon nitride probes. In addition, a FIB-based method for post-growth alignment of the fabricated SiNW tips is presented, which allows tilt-compensation specifically tailored to the specifications of the used AFM instrumentation. To demonstrate the capability of such soft, high-aspect ratio AFM probes, optical gratings fabricated in GaAs and silver halide fibers were imaged in PFT mode. Additionally, the mechanical stability of these high-aspect AFM probes was evaluated on a sapphire substrate.

  2. Tables of Transition Probabilities and Branching Ratios for Electric Dipole Transitions Between Arbitrary Levels of Hydrogen-Like Atoms

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1980-01-01

    Branching ratios in hydrogen-like atoms due to electric-dipole transitions are tabulated for the initial principal and angular momentum quantum number n, lambda, and final principal and angular momentum quantum numbers n, lambda. In table 1, transition probabilities are given for transitions n, lambda, yields n, where sums have been made with respect to lambda. In this table, 2 or = n' or = 10, o or = lambda' or = n'-1, and 1 or = n or = n'-1. In addition, averages with respect to lambda' and sums with respect to n, and lifetimes are given. In table 2, branching ratios are given for transitions n' lambda' yields ni, where sums have been made with respect to lambda. In these tables, 2 or = n' or = 10, 0 or = lambda', n'-1, and 1 or = n or = n'-1. Averages with respect to lambda' are also given. In table 3, branching ratios are given for transitions n' lambda' yields in lambda, where 1 or = n or = 5, 0 or = lambda or = n-1, n n' or = 15, and 0 or = lambda' or = n(s), where n(s), is the smaller of the two numbers n'-1 and 6. Averages with respect to lambda' are given.

  3. Fabrication of high-aspect ratio Si pillars for atom probe 'lift-out' and field ionization tips.

    PubMed

    Morris, R A; Martens, R L; Zana, I; Thompson, G B

    2009-04-01

    A process for fabricating high-aspect ratio ( approximately 1:20), micron-sized Si [001] pillars using mechanical and chemical size reduction is presented. A dicing saw was used for mechanically patterning an array of square pillars with side lengths of >20mum. These pillars were then reduced in size using an aqueous NaOH and KOH solution heated to 100 degrees C. The chemical etch reduces the pillar size within the time range amenable for focus ion beam milling and/or attachment for atom probe 'lift-out' specimens. The pillars can be formed with either a flat top surface or into <100nm tip points for direct field ionization.

  4. Measurement of the Thermospheric Oxygen Atom I(7774)/I(8446) Intensity Ratio, and Expectations for Venus and Mars

    NASA Astrophysics Data System (ADS)

    Slanger, Tom G.; O'Neill, E. R.; Sharpee, B. D.; Cosby, P. C.

    2006-09-01

    Radiative recombination is a major source of atomic oxygen emission in the 3p-3s multiplets at 7772-5 Å and 8446 Å at non-auroral latitudes in the terrestrial atmosphere. This is known from a study of a wide range of O-atom Rydberg lines made with intensity-calibrated sky spectra from the Keck telescopes [Slanger et al., 2004]. We have observed that the I(7774)/I(8446) intensity ratio is approximately constant throughout most of the night with a value near 2.3, although both emissions fall rapidly in intensity. However, late at night the ratio plunges by a factor of 5-10, indicating that the 8446 Å source is still present, while the 7774 Å source turns off. This behavior is explained by noting that the 3d-2p triplet transition of atomic oxygen is in close energy coincidence with the solar hydrogen Lyman-beta line at 1025.572 Å. It is therefore to be expected that the oxygen 3d-2p transition will be excited in the high atmosphere, leading to a cascading sequence - 3d-3p(1.13 μm)->3p-3s(8446 Å) ->3s-2p(1304-06 Å) [Meier et al., 1987]. This process is an example of Bowen fluorescence, and because the oxygen ground state is a triplet, only triplet transitions can be generated in this manner, thus excluding quintet 3p-3s 7774 Å production. Therefore, when the radiative recombination process dies away as charged particles are neutralized, Lyman-beta pumping continues. Because of comparable [O+] and [Ne] [Fox, 1996], radiative recombination will proceed at similar rates in the Venus and terrestrial atmospheres, leading to similar intensities of 7774 and 8446 Å radiation. However, the Bowen fluorescence process at Venus may be more pronounced because of proximity to the sun. In the Mars atmosphere, both sources will be substantially weaker. Support for this work comes from NASA Planetary Astronomy and NSF Atmospheric Sciences (Aeronomy), as well as the NSF REU program.

  5. Numerical simulation of the double-to-single ionization ratio for the helium atom in strong laser fields

    NASA Astrophysics Data System (ADS)

    Chen, Zhangjin; Zheng, Yanyan; Yang, Weifeng; Song, Xiaohong; Xu, Junliang; DiMauro, L. F.; Zatsarinny, Oleg; Bartschat, Klaus; Morishita, Toru; Zhao, Song-Feng; Lin, C. D.

    2015-12-01

    We present calculations on the ratio between double and single ionization of helium by a strong laser pulse at a wavelength of 780 nm using the quantitative rescattering (QRS) model. According to this model, the yield for the doubly charged ion He+2 can be obtained by multiplying the returning electron wave packet (RWP) with the total cross sections (TCSs) for electron impact ionization and electron impact excitation of +He in the singlet spin channel. The singlet constraint was imposed since the interaction of the helium atom with the laser and the recollision processes both preserve the total spin of the system. An R -matrix (close-coupling) code is used to obtain accurate TCSs, while the RWPs, according to the QRS, are calculated by the strong-field approximation for high-energy photoelectrons. The laser field, which lowers the required energy for the electron to escape from the nucleus at the time of recollision, is also taken into account. The simulated results are in good agreement with the measured He+2/+He ratio over a broad range of laser intensities. The result demonstrates that the QRS approach based on the rescattering model is fully capable of quantitatively interpreting nonsequential double ionization processes.

  6. DELFIC: Department of Defense Fallout Prediction System. Volume I - Fundamentals

    DTIC Science & Technology

    1979-12-31

    15,625 KT k2 = 0.004 , 15,625 < W KT The characteristic velocity, v, is v = max(u, 2) . (2.2.1b) Center’ Height dz (2.2.2) Temperature Dry ( water is not...are given by eqs. (2.2.1a, b) and k3 is a dimensionless constant of value 0.175. 21 :2U Mass Dry ( water is not condensed) dmI dtent dtIn 1 pa(T)dT...8217 + x e ’mi-ent s+w Term (a) accounts for entrainment dilusion, and term (b) accounts for fallout from the cloud. Water Vapor Mixing Ratio Dry ( water is

  7. Assessment of methods for collecting fallout brake pad wear debris for environmental analysis.

    PubMed

    Sondhi, Akash; Imhoff, Paul T; Dentel, Steven K; Allen, Herbert E

    2010-01-01

    Three methods for collecting or generating fallout brake pad wear debris for environmental analysis were assessed: collection from wheels or hubs of automobiles (natural), generation from an inexpensive sanding process (sanded), and collection of fallout debris from dynamometer tests using the Los Angeles City Traffic protocol (LACT). Brake wear debris was collected from four automobiles with semimetalic brake pads and analyzed for physicochemical properties. For automobiles where all three types of debris were collected, bulk copper mass fractions ranged from 22-23% in sanded particles and 24-27% in LACTparticles, but were reduced to 1-6% in natural debris. The smaller copper mass fraction in natural debris was attributed to contamination with road dust, which was found to comprise 37-97% of the natural particles. The ratio of surface to bulk copper mass fraction was up to five times larger for natural than LACT debris, suggesting that copper may leach into stormwater faster and to a greater extent for natural particles. While the LACT method appears best for collecting only fallout particles, significant differences in copper distributions in the natural and LACT debris suggests that metal distribution in LACT debris may not be representative of fallout particles generated under actual driving conditions, where airborne road dust may play a role. Although dynamometer tests have been the preferred method for generating debris for assessment of metal dissolution from brake particles, data from this study indicate that such samples may result in biased estimates of metal leaching.

  8. Fallout radiation piece-part data base. Final report

    SciTech Connect

    Rausch, A.

    1990-02-23

    The Electromagnetic Pulse (EMP) Mitigation Program evaluates, where possible, mitigate the effects of the nuclear attack. Fallout radiation has been identified as a by product of a nuclear attack which may affect the performance of the regional and national telecommunications system. In an effort to further examine the effects of fallout radiation, this report presents the results of increasing the sample size of the piece part families by increasing the data in the fallout radiation database.

  9. Mapping Nuclear Fallout Using the Weather Research & Forecasting (WRF) Model

    DTIC Science & Technology

    2012-09-01

    Zucchini , 0.8 R/h at H+1 ................... 50  Figure 13. WRF Fallout Prediction for Test Shot Zucchini , 0.2 R/h at H+1 ................... 51...Figure 14. WRF Fallout Prediction for Test Shot Zucchini , 0.08 R/h at H+1 ................. 51  Figure 15. WRF Fallout Prediction for Test Shot... Zucchini , 0.02 R/h at H+1 ................. 52  Figure 16. WRF Fallout Prediction for Test Shot Zucchini , 0.008 R/h at H+1 ............... 52  Figure 17

  10. Reconstruction of local fallout composition and gamma-ray exposure in a village contaminated by the first USSR nuclear test in the Semipalatinsk nuclear test site in Kazakhstan.

    PubMed

    Imanaka, Tetsuji; Yamamoto, Masayoshi; Kawai, Kenta; Sakaguchi, Aya; Hoshi, Masaharu; Chaizhunusova, Nailya; Apsalikov, Kazbek

    2010-11-01

    After the disintegration of the USSR in end of 1991, it became possible for foreign scientists to visit Kazakhstan, in order to investigate the radiological consequences of nuclear explosions that had been conducted at the Semipalatinsk nuclear test site (SNTS). Since the first visit in 1994, our group has been continuing expeditions for soil sampling at various areas around SNTS. The current level of local fallout at SNTS was studied through γ-spectrometry for (137)Cs as well as α-spectrometry for (239,240)Pu. Average values of soil inventory from wide areas around SNTS were 3,500 and 3,700 Bq m(-2) for (137)Cs and (239,240)Pu, respectively, as of January 1, 2000. The average level of (137)Cs is comparable to that in Japan due to global fallout, while the level of (239,240)Pu is several tens of times larger than that in Japan. Areas of strong contamination were found along the trajectories of radioactive fallout, information on which was declassified after the collapse of the USSR. Our recent efforts of soil sampling were concentrated on the area around the Dolon village heavily affected by the radioactive plume from the first USSR atomic bomb test in 1949 and located 110 km east from ground zero of the explosion. Using soil inventory data, retrospective dosimetry was attempted by reconstructing γ-ray exposure from fission product nuclides deposited on the ground. Adopting representative parameters for the initial (137)Cs deposition (13 kBq m(-2)), the refractory/volatile deposition ratio (3.8) and the plume arrival time after explosion (2.5 h), an absorbed dose in air of 600 mGy was obtained for the 1-year cumulative dose in Dolon village, due to the first bomb test in 1949. Considering possible ranges of the parameters, 350 and 910 mGy were estimated for high and low cases of γ-ray dose in air, respectively. It was encouraging that the deduced value was consistent with other estimations using thermal luminescence and archived monitoring data. The present

  11. Fallout: The experiences of a medical team in the care of a Marshallese population accidentally exposed to fallout radiation

    SciTech Connect

    Conard, R.A.

    1991-12-31

    This report presents an historical account of the experiences of the Brookhaven Medical team in the examination and treatment of the Marshallese people following their accidental exposure to radioactive fallout in 1954. This is the first time that a population has been heavily exposed to radioactive fallout, and even though this was a tragic mishap, the medical findings have provided valuable information for other accidents involving fallout such as the recent reactor accident at Chernobyl. Particularly important has been the unexpected importance of radioactive iodine in the fallout in producing thyroid abnormalities.

  12. Fallout: The experiences of a medical team in the care of a Marshallese population accidentally exposed to fallout radiation

    SciTech Connect

    Conard, R.A.

    1991-01-01

    This report presents an historical account of the experiences of the Brookhaven Medical team in the examination and treatment of the Marshallese people following their accidental exposure to radioactive fallout in 1954. This is the first time that a population has been heavily exposed to radioactive fallout, and even though this was a tragic mishap, the medical findings have provided valuable information for other accidents involving fallout such as the recent reactor accident at Chernobyl. Particularly important has been the unexpected importance of radioactive iodine in the fallout in producing thyroid abnormalities.

  13. Fallout: The experiences of a medical team in the care of a Marshallese population accidently exposed to fallout radiation

    SciTech Connect

    Conard, R.A.

    1992-09-01

    This report presents an historical account of the experiences of the Brookhaven Medical Team in the examination and treatment of the Marshallese people following their accidental exposure to radioactive fallout in 1954. This is the first time that a population has been heavily exposed to radioactive fallout, and even though this was a tragic mishap, the medical findings have provided valuable information for other accidents involving fallout such as the recent reactor accident at Chernobyl. Noteworthy has been the unexpected importance of radioactive iodine in the fallout in producing thyroid abnormalities.

  14. Pt-Al2O3 dual layer atomic layer deposition coating in high aspect ratio nanopores.

    PubMed

    Pardon, Gaspard; Gatty, Hithesh K; Stemme, Göran; van der Wijngaart, Wouter; Roxhed, Niclas

    2013-01-11

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al(2)O(3)) on Pt in nanopores to form a metal-insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al(2)O(3) layer on such a Pt film forms a metal-insulator-electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 μm thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al(2)O(3) using ALD.

  15. Zeeman splitting, its specific features, and gyromagnetic ratios for configurations 1 snf ( n = 4-10) of the helium atom

    NASA Astrophysics Data System (ADS)

    Anisimova, G. P.; Gorbenko, A. P.; Dolmatova, O. A.; Krylov, I. R.; Mashek, I. Ch.; Tsygankova, G. A.

    2016-02-01

    The fine structure parameters of configurations 1 snf ( n = 4-10) with new refined energy values are calculated by the semiempirical method. The emphasis is on the study of the Zeeman structure in order to determine the gyromagnetic ratios of all four the levels of the configuration from the splitting. For this purpose, the matrices of an energy operator with allowance for the interaction between the atom and a magnetic field were diagonalized for all possible values of quantum number M. For each configuration, 17 values of crossing fields of the Zeeman sublevels with Δ M = ±1, ±2 and the regions of anticrossings with Δ M = 0 were determined. It is remarkable that, because the levels are closely spaced, anticrossings are observed for each pair of levels in these systems. The regions of linearity of a magnetic field, which are different for different configurations, and the levels in them are established. The g-factors are calculated from the coefficients of an intermediate coupling scheme in a magnetic field that is guaranteed to be linear. They are compared with the analogous values in the absence of a field.

  16. C/O atomic ratios in micrometer-size crushed grains from Antarctic micrometeorites and two carbonaceous meteorites

    NASA Technical Reports Server (NTRS)

    Perreau, M.; Engrand, C.; Maurette, Michel; Kurat, G.; Presper, TH.

    1993-01-01

    Antarctic micrometeorites (AMM's) have similarities (but also differences) with primitive meteorites, such as unequilibrated mineral assemblages. To further assess such similarities, we have measured the carbon content of micrometeorites and meteorites (Orgueil and Murchison), as determined in a random selection of micrometer-size crushed grain, with an analytical transmission electron microscope. Such analyses yield the C/O atomic ratio, the major and minor elements contents, and the textural features of the grains on a scale of approx. equal to 100 nanometers. An important proportion of micrometeorites from both the 100-400 micron and the 50-100 micron size fractions contains much more carbon than CI chondrite Orgueil. The average C-content of all micrometeorites in these two size fractions amount to approximately 1.8 x CI, and approximately 0.8 x CI, respectively (CI refers to the bulk C-content of Orgueil, of about 3.5 percent by weight). Carbon is usually not homogeneously distributed in the micrometeorite but is concentrated in C-rich grains. So far, most of these grains are amorphous, and seem to be associated with an oxidized Fe-rich phase (possibly a variety of 'dirty' magnetite). About 5 percent of them have the composition of 'COPS', a phase additionally enriched in O, P, and S.

  17. Radioactive Fallout from Terrorist Nuclear Detonations

    SciTech Connect

    Marrs, R E

    2007-05-03

    Responding correctly during the first hour after a terrorist nuclear detonation is the key to reducing casualties from a low-yield surface burst, and a correct response requires an understanding of the rapidly changing dose rate from fallout. This report provides an empirical formula for dose rate as a function of time and location that can guide the response to an unexpected nuclear detonation. At least one post-detonation radiation measurement is required if the yield and other characteristics of the detonation are unknown.

  18. [Comparative analysis of the radionuclide composition in fallout after the Chernobyl and the Fukushima accidents].

    PubMed

    Kotenko, K V; Shinkarev, S M; Abramov, Iu V; Granovskaia, E O; Iatsenko, V N; Gavrilin, Iu I; Margulis, U Ia; Garetskaia, O S; Imanaka, T; Khoshi, M

    2012-01-01

    The nuclear accident occurred at Fukushima Dai-ichi Nuclear Power Plant (NPP) (March 11, 2011) similarly to the accident at the Chernobyl NPP (April 26, 1986) is related to the level 7 of the INES. It is of interest to make an analysis of the radionuclide composition of the fallout following the both accidents. The results of the spectrometric measurements were used in that comparative analysis. Two areas following the Chernobyl accident were considered: (1) the near zone of the fallout - the Belarusian part of the central spot extended up to 60 km around the Chernobyl NPS and (2) the far zone of the fallout--the "Gomel-Mogilev" spot centered 200 km to the north-northeast of the damaged reactor. In the case of Fukushima accident the near zone up to about 60 km considered. The comparative analysis has been done with respect to refractory radionuclides (95Zr, 95Nb, 141Ce, 144Ce), as well as to the intermediate and volatile radionuclides 103Ru, 106Ru, 131I, 134Cs, 137Cs, 140La, 140Ba and the results of such a comparison have been discussed. With respect to exposure to the public the most important radionuclides are 131I and 137Cs. For the both accidents the ratios of 131I/137Cs in the considered soil samples are in the similar ranges: (3-50) for the Chernobyl samples and (5-70) for the Fukushima samples. Similarly to the Chernobyl accident a clear tendency that the ratio of 131I/137Cs in the fallout decreases with the increase of the ground deposition density of 137Cs within the trace related to a radioactive cloud has been identified for the Fukushima accident. It looks like this is a universal tendency for the ratio of 131I/137Cs versus the 137Cs ground deposition density in the fallout along the trace of a radioactive cloud as a result of a heavy accident at the NPP with radionuclides releases into the environment. This tendency is important for an objective reconstruction of 131I fallout based on the results of 137Cs measurements of soil samples carried out at

  19. Assessment of spatial distribution of fallout radionuclides through geostatistics concept.

    PubMed

    Mabit, L; Bernard, C

    2007-01-01

    After introducing geostatistics concept and its utility in environmental science and especially in Fallout Radionuclide (FRN) spatialisation, a case study for cesium-137 ((137)Cs) redistribution at the field scale using geostatistics is presented. On a Canadian agricultural field, geostatistics coupled with a Geographic Information System (GIS) was used to test three different techniques of interpolation [Ordinary Kriging (OK), Inverse Distance Weighting power one (IDW1) and two (IDW2)] to create a (137)Cs map and to establish a radioisotope budget. Following the optimization of variographic parameters, an experimental semivariogram was developed to determine the spatial dependence of (137)Cs. It was adjusted to a spherical isotropic model with a range of 30 m and a very small nugget effect. This (137)Cs semivariogram showed a good autocorrelation (R(2)=0.91) and was well structured ('nugget-to-sill' ratio of 4%). It also revealed that the sampling strategy was adequate to reveal the spatial correlation of (137)Cs. The spatial redistribution of (137)Cs was estimated by Ordinary Kriging and IDW to produce contour maps. A radioisotope budget was established for the 2.16 ha agricultural field under investigation. It was estimated that around 2 x 10(7)Bq of (137)Cs were missing (around 30% of the total initial fallout) and were exported by physical processes (runoff and erosion processes) from the area under investigation. The cross-validation analysis showed that in the case of spatially structured data, OK is a better interpolation method than IDW1 or IDW2 for the assessment of potential radioactive contamination and/or pollution.

  20. Qualitative tissue differentiation by analysing the intensity ratios of atomic emission lines using laser induced breakdown spectroscopy (LIBS): prospects for a feedback mechanism for surgical laser systems.

    PubMed

    Kanawade, Rajesh; Mahari, Fanuel; Klämpfl, Florian; Rohde, Maximilian; Knipfer, Christian; Tangermann-Gerk, Katja; Adler, Werner; Schmidt, Michael; Stelzle, Florian

    2015-01-01

    The research work presented in this paper focuses on qualitative tissue differentiation by monitoring the intensity ratios of atomic emissions using 'Laser Induced Breakdown Spectroscopy' (LIBS) on the plasma plume created during laser tissue ablation. The background of this study is to establish a real time feedback control mechanism for clinical laser surgery systems during the laser ablation process. Ex-vivo domestic pig tissue samples (muscle, fat, nerve and skin) were used in this experiment. Atomic emission intensity ratios were analyzed to find a characteristic spectral line for each tissue. The results showed characteristic elemental emission intensity ratios for the respective tissues. The spectral lines and intensity ratios of these specific elements varied among the different tissue types. The main goal of this study is to qualitatively and precisely identify different tissue types for tissue specific laser surgery.

  1. Laboratory Study of Airborne Fallout Particles and Their Time Distribution.

    ERIC Educational Resources Information Center

    Smith, H. A., Jr.; And Others

    1979-01-01

    Samples of filtered airborne particulate, collected daily for the first month after the September 18, 1977 Chinese nuclear detonation, showed fourteen fission products. Fluctuations in the daily fallout activity levels suggested a global fallout orbit time of approximately twenty days. (Author/BB)

  2. Halogen Atom Ratios in the Springtime Arctic Troposphere as Determined From Measurements of Halogenated Volatile Organic Compounds

    NASA Astrophysics Data System (ADS)

    Keil, A.; Shepson, P. B.

    2005-12-01

    The concentrations of a suite of halogenated volatile organic compounds (HVOCs) were measured near Barrow, Alaska from January to April 2005. The HVOCs are produced from the reaction of ethene and propene with bromine and chlorine atoms, which are important atmospheric oxidants in the Arctic troposphere. Chlorine atom oxidation is responsible for significant decreases in non-methane hydrocarbons and bromine atoms are thought to be responsible for the catalytic destruction of tropospheric ozone and mercury. The HVOC concentrations are used to probe the sources of these halogen atoms and their relative ambient concentrations. We find evidence for local production of the halogen atom precursors, and determine [Br]/[Cl] to be between 20 and 300, somewhat lower than those determined by VOC decay methods.

  3. Evidence of the radioactive fallout in the center of Asia (Russia) following the Fukushima Nuclear Accident.

    PubMed

    Bolsunovsky, A; Dementyev, D

    2011-11-01

    It was recently reported that radioactive fallout due to the Fukushima Nuclear Accident was detected in environmental samples collected in the USA and Greece, which are very far away from Japan. In April-May 2011, fallout radionuclides ((134)Cs, (137)Cs, (131)I) released in the Fukushima Nuclear Accident were detected in environmental samples at the city of Krasnoyarsk (Russia), situated in the center of Asia. Similar maximum levels of (131)I and (137)Cs/(134)Cs and (131)I/(137)Cs ratios in water samples collected in Russia and Greece suggest the high-velocity movement of the radioactive contamination from the Fukushima Nuclear Accident and the global effects of this accident, similar to those caused by the Chernobyl accident.

  4. Long-range volcanic ash transport and fallout during the 2008 eruption of Chaiten volcano, Chile

    NASA Astrophysics Data System (ADS)

    Durant, A. J.; Prata, A. J.; Villarosa, G.; Rose, W. I.; Delmelle, P.; Viramonte, J.

    2012-04-01

    The May 2008 eruption of Chaitén volcano, Chile, provided a rare opportunity to measure the long-range transport of volcanic emissions and characteristics of a widely-dispersed terrestrial ash deposit. Airborne ash mass, quantified using thermal infrared satellite remote sensing, ranged between 0.2-0.4 Tg during the period 3-7 May 2008. A high level of spatiotemporal correspondence was observed between cloud trajectories and changes in surface reflectivity, which was inferred to indicate ash deposition. The evolution of the deposit was mapped for the first time using satellite-based observations of surface reflectivity. The distal (>80 km) ash deposit was poorly sorted and fine grained, and mean particle size varied very little beyond a distance >300 km. There were 3 consistent particle size subpopulations in fallout at distances >300 km which suggests that aggregation influenced particle settling. Discrete temporal sampling and characterisation of fallout demonstrated contributions from specific eruptive phases. Some evidence for winnowing was identified through comparison of samples collected at the time of deposition to bulk samples collected months after deposition. X-Ray Photoelectron Spectroscopy (XPS) analyses revealed surface enrichments in Ca, Na and Fe and the presence of coatings of mixed Ca-, Na- and Fe-rich salts on ash particles prior to deposition. XPS analyses revealed strong surface Fe enrichments (in contrast to the results from bulk leachate analyses), which indicates that surface analysis techniques should be applied to investigate potential influences on ocean productivity in response to volcanic ash fallout over oceans. Low S:Cl ratios in leachates indicate that the eruption had a low S content, and high Cl:F ratios imply gas-ash interaction within a Cl-rich environment. We estimate that ash fallout had potential to scavenge ~42 % of total S released into the atmosphere prior to deposition.

  5. Long-term investigations of post-Chernobyl radiocaesium in fallout and air in North Croatia.

    PubMed

    Franić, Zdenko; Sega, Kresimir; Petrinec, Branko; Marović, Gordana

    2009-01-01

    The long-term behaviour of (137)Cs activity concentrations in air and fallout has been studied in the city of Zagreb for the post-Chernobyl period (1986-2006) as a part of an extended monitoring program of radioactive contamination of human environment in Croatia. Annual mean (137)Cs activity concentrations in air and annual total deposition fluxes (wet plus dry) decreased from 2.8 x 10(-4) Bq m(-3) in September 1986 to 3.0 x 10(-6) Bq m(-3) in last quarter of 2006 and from 6,410 Bq m(-2) year(-1) in 1986 to 2 Bq m(-2) year(-1) in 2006 respectively. By fitting the measured (137)Cs activity concentrations to the theoretical curve the ecological half-lives of (137)Cs in air and fallout were estimated with respective values of 0.46 and 0.54 years for immediate post-Chernobyl period, increasing to 5.52 and 3.97 years afterwards. Using the data on (137)Cs activity concentrations in air and fallout total caesium deposition velocity of (3.34 +/- 3.13) x 10(-2) ms(-1) was estimated with median value being 2.13 x 10(-2) ms(-1). Such relatively high (137)Cs deposition velocities compared with pre-Chernobyl ones, are characteristic for the post-Chernobyl period and, according to Stokes' settling law, indicate that the diameters of aerosol particles associated with (137)Cs originated from the Chernobyl accident are pretty large, i.e. >1 microm. (134)Cs/(137)Cs activity ratio in fallout and in air has been found to be similar to the theoretically predicted values, initial value being about 0.5 and decreasing according to differential radioactive decay. The similar ratio has been observed in most of the other environmental samples.

  6. Predictive Fallout Composition Modeling: Improvements and Applications of the Defense Land Fallout Interpretive Code

    SciTech Connect

    Hooper, David A; Jodoin, Vincent J; Lee, Ronald W; Monterial, Mateusz

    2012-01-01

    This paper outlines several improvements to the Particle Activity Module of the Defense Land Fallout Interpretive Code (DELFIC). The modeling of each phase of the fallout process is discussed within DELFIC to demonstrate the capabilities and limitations with the code for modeling and simulation. Expansion of the DELFIC isotopic library to include actinides and light elements is shown. Several key features of the new library are demonstrated, including compliance with ENDF/B-VII standards, augmentation of hardwired activated soil and actinide decay calculations with exact Bateman calculations, and full physical and chemical fractionation of all material inventories. Improvements to the radionuclide source term are demonstrated, including the ability to specify heterogeneous fission types and the ability to import source terms from irradiation calculations using the Oak Ridge Isotope Generation (ORIGEN) code. Additionally, the dose, kerma, and effective dose conversion factors are revised. Finally, the application of DELFIC for consequence management planning and forensic analysis is presented. For consequence management, DELFIC is shown to provide disaster recovery teams with simulations of real-time events, including the location, composition, time of arrival, activity rates, and dose rates of fallout, accounting for site-specific atmospheric effects. The results from DELFIC are also demonstrated for use by nuclear forensics teams to plan collection routes (including the determination of optimal collection locations), estimate dose rates to collectors, and anticipate the composition of material at collection sites. These capabilities give mission planners the ability to maximize their effectiveness in the field while minimizing risk to their collectors.

  7. Network-level fallout radiation effects assessment. Final report

    SciTech Connect

    Not Available

    1991-05-01

    National Security calls for the ability to maintain communication capabilities in times of national disaster, which could include a nuclear attack. Nuclear detonation has two basic by-products for which telecommunication equipments are susceptible to damage. These are electromagnetic pulse (EMP) and fallout radiation. The purposes of the EMP Mitigation Program are to analyze and to lessen the effects of EMP and fallout radiation on national telecommunications resources. Fallout radiation occurs after the initial intense high-frequency EMP, and is the subject of this analysis. Fallout radiation is the residual radiation that remains in the atmosphere after a nuclear blast, and which can be carried by weather conditions to locations far from the detonation point. This analysis focuses on the effects of fallout radiation on the telecommunications network of the American Telephone and Telegraph Co. (AT and T). This assessment of AT and T-network's communications-capabilities uses a network-level approach to assess fallout-radiation effects on the network's performance. The approach used was developed for assessing network-level EMP effects on Public Switched Network communication capabilities. Details are given on how EMP assessments utilize this method. Equipment-level fallout-radiation survivability data is also required.

  8. Determination of (239)Pu, (240)Pu, (241)Pu and (242)Pu at femtogram and attogram levels - evidence for the migration of fallout plutonium in an ombrotrophic peat bog profile.

    PubMed

    Quinto, Francesca; Hrnecek, Erich; Krachler, Michael; Shotyk, William; Steier, Peter; Winkler, Stephan R

    2013-04-01

    The isotopic composition of plutonium ((239)Pu, (240)Pu, (241)Pu and (242)Pu) was investigated in a ∼0.5 m long peat core from an ombrotrophic bog (Black Forest, Germany) using clean room procedures and accelerator mass spectrometry (AMS). This sophisticated analytical approach was ultimately needed to detect reliably the Pu concentrations present in the peat samples at femtogram (fg) and attogram (ag) levels. The mean (240)Pu/(239)Pu isotopic ratio of 0.19 ± 0.02 (N = 32) in the peat layers, representing approximately the last 80 years, was in good agreement with the accepted value of 0.18 for the global fallout in the Northern Hemisphere. This finding is largely supported by the corresponding and rather constant (241)Pu/(239)Pu (0.0012 ± 0.0005) and (242)Pu/(239)Pu (0.004 ± 0.001) ratios. Since the Pu isotopic composition characteristic of the global fallout was also identified in peat samples pre-dating the period of atmospheric atom bomb testing (AD 1956-AD 1980), migration of Pu within the peat profile is clearly indicated. These results highlight, for the first time, the mobility of Pu in a peat bog with implications for the migration of Pu in other acidic, organic rich environments such as forest soils and other wetland types. These findings constitute a direct observation of the behaviour of Pu at fg and ag levels in the environment. The AMS measurements of Pu concentrations (referring to a corresponding activity of (240+239)Pu from 0.07 mBq g(-1) to 5 mBq g(-1)) essentially confirm our a priori estimates based on existing (241)Am and (137)Cs data in the investigated peat core and agree well with the global fallout levels from the literature. Exclusively employing the Pu isotope ratios established for the peat samples, the date of the Pu irradiation (AD 1956, correctable to AD 1964) was calculated and subsequently compared to the (210)Pb age of the peat layers; this comparison provided an additional hint that global fallout derived Pu is not fixed in

  9. Remarkably Gaussian Tephra Fallout from Basaltic Eruptions

    NASA Astrophysics Data System (ADS)

    Courtland, L. M.; Kruse, S.; Connor, C.

    2008-12-01

    Tephra fallout models used to forecast volcanic hazards rely on the advection-diffusion equation to forecast hazards. If the advection-diffusion equation applies, then the thickness of tephra blanket deposits should show Gaussian crosswind profiles and exponential decay with distance from the vent. Complications may arise due to factors such as particle size distributions, particle density, and atmospheric effects not incorporated in the advection-diffusion model. Continuous profiles derived from GPR surveys collected on the tephra blanket of Cerro Negro Volcano, Nicaragua allow us to test the advection-diffusion model. Steady trade winds coupled with eruptions that tend to be brief and relatively low energy create relatively simple deposits. Data was collected for cross wind profiles at varying distances from the vent. Horizons identified in these profiles exhibit Gaussian distributions with a high degree of statistical confidence. Additionally, the shape of one continuous profile leading from the crater rim out onto the tephra blanket is examined.

  10. Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

    SciTech Connect

    Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.; Weber, Peter K.; Prussin, Stan G.; Hutcheon, Ian D.

    2016-10-29

    In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device (235U/238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a

  11. Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

    DOE PAGES

    Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; ...

    2016-10-29

    In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamicmore » fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device (235U/238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also

  12. Tracking Radioactive Fallout from the Fukushima Dai-ichi Accident in Arctic Snow

    NASA Astrophysics Data System (ADS)

    Osterberg, E. C.; Thompson, J.; Landis, J.; Albert, M. R.; Campbell, S. W.; Hawley, R. L.; Virginia, R. A.

    2011-12-01

    The March 11, 2011 magnitude 9.0 Tohoku, Japan earthquake produced a tsunami that inundated the Fukushima Dai-ichi nuclear power plant and led to the accidental release of radioactive 131I, 132Te, 134Cs, and 137Cs to the atmosphere. The Japanese Nuclear Safety Commission estimates that 12,000 TBq of 137Cs were released to the atmosphere during the incident, which represents ~14% of the total estimated 137Cs emission from the Chernobyl disaster in April 1986. Measurements of airborne radiation collected at the Fukushima plant illustrate that >50% of the total emitted radiation was released on March 15 and 16 associated with explosions and fires at reactor units 1, 2, and 4, and 70% was emitted in the first 5 days of the event. The source of the radiation is thus well constrained in time and space, providing an opportunity to better understand long-range atmospheric transport processes from Asia to the Arctic, while also assessing the magnitude of the fallout in the Arctic. Here we describe the 137Cs and 134Cs fallout flux near Thule, Greenland (1700 m a.s.l.), at Summit (3200 m a.s.l.), Greenland, and within Denali National Park, Alaska (2400-3900 m a.s.l.) based on series of large-volume (5-15 l) snow pit samples collected in June and July, 2011. In addition to assessing the spatial variability of Fukushima fallout in the Arctic, the elevation range of samples allows for an analysis of any vertical heterogeneity in fallout transport and deposition. Major ion concentrations and stable water isotope ratios are used to confirm the seasonal timing of the Fukushima fallout horizon in the snowpack. Radiocesium was concentrated and isolated from the snow pit meltwater using the well-established ammonium phosphomolybdate (AMP) adsorption method, and 134Cs and 137Cs concentrations were measured using gamma spectrometry with a Canberra 3523 well-type intrinsic Ge-detector at the Dartmouth College Short-Lived Isotope Laboratory. NOAA HYPLIT atmospheric forward

  13. Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

    NASA Astrophysics Data System (ADS)

    Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.; Weber, Peter K.; Prussin, Stan G.; Hutcheon, Ian D.

    2017-03-01

    In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device (235U/238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO2 is found to be relatively invariable across the samples and interfaces (∼3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be

  14. Linus Pauling and the scientific debate over fallout hazards.

    PubMed

    Jolly, J Christopher

    2002-12-01

    From 1954 to 1963, numerous scientists engaged in a public debate over the possible hazards from radioactive fallout from nuclear weapons testing. Nobel laureate Linus Pauling, a California Institute of Technology chemist, was one of the most prominent. His scientific papers relating to the fallout debate reveal many of the scientific, social and political issues involved in the controversy. Although the public controversy ended after the signing of the 1963 Limited Test Ban Treaty, many of the scientific questions about the possible hazards of low-level radiation remain under debate within the scientific community. Moreover, the fallout debate was a prototype of current controversies over environmental and public-health hazards.

  15. European roe deer antlers as an environmental archive for fallout (236)U and (239)Pu.

    PubMed

    Froehlich, M B; Steier, P; Wallner, G; Fifield, L K

    2016-01-01

    Anthropogenic (236)U and (239)Pu were measured in European roe deer antlers hunted between 1955 and 1977 which covers and extends beyond the period of intensive nuclear weapons testing (1954-1962). The antlers were hunting trophies, and hence the hunting area, the year of shooting and the approximate age of each animal is given. Uranium and plutonium are known to deposit in skeletal tissue. Since antler histology is similar to bone, both elements were expected in antlers. Furthermore, roe deer shed their antlers annually, and hence antlers may provide a time-resolved environmental archive for fallout radionuclides. The radiochemical procedure is based on a Pu separation step by anion exchange (Dowex 1 × 8) and a subsequent U purification by extraction chromatography using UTEVA(®). The samples were measured by Accelerator Mass Spectrometry at the VERA facility (University of Vienna). In addition to the (236)U and (239)Pu concentrations, the (240)Pu/(239)Pu isotopic ratios were determined with a mean value of 0.172 ± 0.023 which is in agreement with the ratio of global fallout (∼0.18). Rather high (236)U/(238)U ratios of the order of 10(-6) were observed. These measured ratios, where the (236)U arises only from global fallout, have implications for the use of the (236)U/(238)U ratio as a fingerprint for nuclear accidents or releases from nuclear facilities. Our investigations have shown the potential to use antlers as a temporally resolved archive for the uptake of actinides from the environment.

  16. Plutonium concentration and isotopic ratio in soil samples from central-eastern Japan collected around the 1970s.

    PubMed

    Yang, Guosheng; Zheng, Jian; Tagami, Keiko; Uchida, Shigeo

    2015-04-16

    Obtaining Pu background data in the environment is essential for contamination source identification and assessment of environmental impact of Pu released from the Fukushima Daiichi nuclear power plant (FDNPP) accident. However, no baseline information on Pu isotopes in Fukushima Prefecture has been reported. Here we analyzed 80 surface soil samples collected from the central-eastern Japan during 1969-1977 for (239+240)Pu activity concentration and (240)Pu/(239)Pu atom ratio to establish the baseline before the FDNPP accident. We found that (239+240)Pu activity concentrations ranged from 0.004 -1.46 mBq g(-1), and (240)Pu/(239)Pu atom ratios varied narrowly from 0.148 to 0.229 with a mean of 0.186 ± 0.015. We also reconstructed the surface deposition density of (241)Pu using the (241)Pu/(239)Pu atom ratio in the Japanese fallout reference material. The obtained results indicated that, for the FDNPP-accident released (241)Pu, a similar radiation impact can be estimated as was seen for the global fallout deposited (241)Pu in the last decades.

  17. Plutonium concentration and isotopic ratio in soil samples from central-eastern Japan collected around the 1970s

    PubMed Central

    Zheng, Jian; Tagami, Keiko; Uchida, Shigeo

    2015-01-01

    Obtaining Pu background data in the environment is essential for contamination source identification and assessment of environmental impact of Pu released from the Fukushima Daiichi nuclear power plant (FDNPP) accident. However, no baseline information on Pu isotopes in Fukushima Prefecture has been reported. Here we analyzed 80 surface soil samples collected from the central-eastern Japan during 1969–1977 for 239+240Pu activity concentration and 240Pu/239Pu atom ratio to establish the baseline before the FDNPP accident. We found that 239+240Pu activity concentrations ranged from 0.004 –1.46 mBq g−1, and 240Pu/239Pu atom ratios varied narrowly from 0.148 to 0.229 with a mean of 0.186 ± 0.015. We also reconstructed the surface deposition density of 241Pu using the 241Pu/239Pu atom ratio in the Japanese fallout reference material. The obtained results indicated that, for the FDNPP-accident released 241Pu, a similar radiation impact can be estimated as was seen for the global fallout deposited 241Pu in the last decades. PMID:25881009

  18. Plutonium concentration and isotopic ratio in soil samples from central-eastern Japan collected around the 1970s

    NASA Astrophysics Data System (ADS)

    Yang, Guosheng; Zheng, Jian; Tagami, Keiko; Uchida, Shigeo

    2015-04-01

    Obtaining Pu background data in the environment is essential for contamination source identification and assessment of environmental impact of Pu released from the Fukushima Daiichi nuclear power plant (FDNPP) accident. However, no baseline information on Pu isotopes in Fukushima Prefecture has been reported. Here we analyzed 80 surface soil samples collected from the central-eastern Japan during 1969-1977 for 239+240Pu activity concentration and 240Pu/239Pu atom ratio to establish the baseline before the FDNPP accident. We found that 239+240Pu activity concentrations ranged from 0.004 -1.46 mBq g-1, and 240Pu/239Pu atom ratios varied narrowly from 0.148 to 0.229 with a mean of 0.186 +/- 0.015. We also reconstructed the surface deposition density of 241Pu using the 241Pu/239Pu atom ratio in the Japanese fallout reference material. The obtained results indicated that, for the FDNPP-accident released 241Pu, a similar radiation impact can be estimated as was seen for the global fallout deposited 241Pu in the last decades.

  19. H/C atomic ratio as a smart linkage between pyrolytic temperatures, aromatic clusters and sorption properties of biochars derived from diverse precursory materials

    NASA Astrophysics Data System (ADS)

    Xiao, Xin; Chen, Zaiming; Chen, Baoliang

    2016-03-01

    Biochar is increasingly gaining attention due to multifunctional roles in soil amelioration, pollution mitigation and carbon sequestration. It is a significant challenge to compare the reported results from world-wide labs regarding the structure and sorption of biochars derived from various precursors under different pyrolytic conditions due to a lack of a simple linkage. By combining the published works on various biochars, we established a quantitative relationship between H/C atomic ratio and pyrolytic temperature (T), aromatic structure, and sorption properties for naphthalene and phenanthrene. A reverse sigmoid shape between T and the H/C ratio was observed, which was independent of the precursors of biochars, including the ash contents. Linear correlations of Freundlich parameters (N, log Kf) and sorption amount (log Qe, log QA) with H/C ratios were found. A rectangle-like model was proposed to predict the aromatic cluster sizes of biochars from their H/C ratios, and then a good structure-sorption relationship was derived. These quantitative relationships indicate that the H/C atomic ratio is a universal linkage to predict pyrolytic temperatures, aromatic cluster sizes, and sorption characteristics. This study would guide the global study of biochars toward being comparable, and then the development of the structure-sorption relationships will benefit the structural design and environmental application of biochars.

  20. H/C atomic ratio as a smart linkage between pyrolytic temperatures, aromatic clusters and sorption properties of biochars derived from diverse precursory materials

    PubMed Central

    Xiao, Xin; Chen, Zaiming; Chen, Baoliang

    2016-01-01

    Biochar is increasingly gaining attention due to multifunctional roles in soil amelioration, pollution mitigation and carbon sequestration. It is a significant challenge to compare the reported results from world-wide labs regarding the structure and sorption of biochars derived from various precursors under different pyrolytic conditions due to a lack of a simple linkage. By combining the published works on various biochars, we established a quantitative relationship between H/C atomic ratio and pyrolytic temperature (T), aromatic structure, and sorption properties for naphthalene and phenanthrene. A reverse sigmoid shape between T and the H/C ratio was observed, which was independent of the precursors of biochars, including the ash contents. Linear correlations of Freundlich parameters (N, log Kf) and sorption amount (log Qe, log QA) with H/C ratios were found. A rectangle-like model was proposed to predict the aromatic cluster sizes of biochars from their H/C ratios, and then a good structure-sorption relationship was derived. These quantitative relationships indicate that the H/C atomic ratio is a universal linkage to predict pyrolytic temperatures, aromatic cluster sizes, and sorption characteristics. This study would guide the global study of biochars toward being comparable, and then the development of the structure-sorption relationships will benefit the structural design and environmental application of biochars. PMID:26940984

  1. Analysis of meteorological and radiological data for selected fallout episodes

    SciTech Connect

    Quinn, V.E. )

    1990-11-01

    The Weather Service Nuclear Support Office has analyzed the meteorological and radiological data collected for the following atmospheric nuclear tests: TRINITY; EASY of the Tumbler-Snapper series; ANNIE, NANCY, BADGER, SIMON, and HARRY of the Upshot-Knothole series; BEE and ZUCCHINI of the Teapot series; BOLTZMANN and SMOKY of the Plumbbob series; and SMALL BOY of the Dominic II series. These tests were chosen as having the greatest impact on nearby downwind populated locations, contributing approximately 80% of the collective estimated exposure. This report describes the methods of analysis used in deriving fallout-pattern contours and estimated fallout arrival times. Inconsistencies in the radiological data and their resolution are discussed. The methods of estimating fallout arrival times from the meteorological data are described. Comparisons of fallout patterns resulting from these analyses with earlier analyses show insignificant differences in the areas covered or people exposed.

  2. 37. Threequarter view of building 161, fallout shelter, showing building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. Three-quarter view of building 161, fallout shelter, showing building 104, mess hall in background, looking southeast - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  3. 31. Threequarter view of front of building 161, fallout shelter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. Three-quarter view of front of building 161, fallout shelter taken from top of water storage mound, looking northwest - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  4. 38. Overall view showing building 161, fallout shelter on far ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. Overall view showing building 161, fallout shelter on far right, and building 102, officers quarters and enlisted men barracks on far left, looking east - Nike Missile Battery MS-40, County Road No. 260, Farmington, Dakota County, MN

  5. Activities of Pu and Am isotopes and isotopic ratios in a soil contaminated by weapons-grade plutonium.

    PubMed

    Lee, M H; Clark, S B

    2005-08-01

    An accident and fire at the former McGuire Air Force Base and Boeing Michigan Aeronautical Research Center (BOMARC) site in New Jersey resulted in dispersion of weapons-grade plutonium in particulate form to the local environment. Soil samples collected at the BOMARC site were measured for their activities and isotopic ratios of Pu and Am isotopes by radioanalytical techniques. The activities of the Pu and Am isotopes in the BOMARC soil were markedly higher than fallout levels, and they decreased nearly exponentially with increasing particle size of the soil. The measured (241)Am activity was compared to calculated values based on decay of (241)Pu. The activity ratios of (238)Pu/(239,240)Pu, (241)Pu/(239,240)Pu, and (241)Am/(239,240)Pu observed in the BOMARC soil were much lower than those attributed to nuclear reprocessing plants and Chernobyl fallout. From the activity ratios of (241)Pu/(239,240)Pu and (241)Am/(239,240)Pu, the origin of the Pu isotopes was identified as weapons-grade and the time since production of the material was estimated. Furthermore, the atomic ratio of (240)Pu/(239)Pu in the BOMARC soil was remarkably lower than the fallout value influenced by nuclear weapons testing and the Chernobyl accident. The atomic ratio of (240)Pu/(239)Pu was very close to the value of the weapons-grade Pu detected from the Thule accident in Greenland. This work demonstrates the utility of radioanalytical measurements and decay calculations for defining characteristics of the source term and discriminating multiple processes that contribute to a source. Such an approach would also be needed to respond to a terrorist event involving an improvised nuclear device or radiological dispersal device.

  6. Distribution, Characteristics, and Biotic Availability of Fallout, Operation Plumbbob

    DTIC Science & Technology

    1957-10-01

    patterns and in the laboratory on samples of fallout material selected according to particle size range, fallout time-of-arrival, and type of device...particle size fractions greater than 44 microns in diameter were characterized according to color, shape, opacity, and prevalent type . Initial observations...106 5.6 Particle Distribution According to Appearance and Size ............ 110 5.7 Radioactivity Per Particle of Different

  7. Ingestion of Nevada Test Site Fallout: Internal dose estimates

    SciTech Connect

    Whicker, F.W.; Kirchner, T.B.; Anspaugh, L.R.

    1996-10-01

    This paper summarizes individual and collective dose estimates for the internal organs of hypothetical yet representative residents of selected communities that received measurable fallout from nuclear detonations at the Nevada Test Site. The doses, which resulted from ingestion of local and regional food products contaminated with over 20 radionuclides, were estimated with use of the PATHWAY food-chain-transport model to provide estimates of central tendency and uncertainty. The thyroid gland received much higher doses than other internal organs and tissues. In a avery few cases, infants might have received thyroid doses in excess of 1 Gy, depending on location, diet, and timing of fallout. {sup 131}I was the primary thyroid dose contributor, and fresh milk was the main exposure pathway. With the exception of the thyroid, organ doses from the ingestion pathway were much smaller (<3%) than those from external gamma exposure to deposited fallout. Doses to residents living closest to the Nevada Test Site were contributed mainly by a few fallout events; doses to more distantly located people were generally smaller, but a greater number of events provided measurable contributions. The effectiveness of different fallout events in producing internal organ doses through ingestion varied dramatically with seasonal timing of the test, with maximum dose per unit fallout occurring for early summer depositions when milk cows were on pasture and fresh, local vegetables were used. Within specific communities, internal doses differed by age, sex, and lifestyle. Collective internal dose estimates for specific geographic areas are provided.

  8. A MODEL BUILDING CODE ARTICLE ON FALLOUT SHELTERS WITH RECOMMENDATIONS FOR INCLUSION OF REQUIREMENTS FOR FALLOUT SHELTER CONSTRUCTION IN FOUR NATIONAL MODEL BUILDING CODES.

    ERIC Educational Resources Information Center

    American Inst. of Architects, Washington, DC.

    A MODEL BUILDING CODE FOR FALLOUT SHELTERS WAS DRAWN UP FOR INCLUSION IN FOUR NATIONAL MODEL BUILDING CODES. DISCUSSION IS GIVEN OF FALLOUT SHELTERS WITH RESPECT TO--(1) NUCLEAR RADIATION, (2) NATIONAL POLICIES, AND (3) COMMUNITY PLANNING. FALLOUT SHELTER REQUIREMENTS FOR SHIELDING, SPACE, VENTILATION, CONSTRUCTION, AND SERVICES SUCH AS ELECTRICAL…

  9. Purification of fallout-contaminated water studied

    SciTech Connect

    Lu Deyuan; Cai, X.; Li, M.; Liu, T.

    1983-04-30

    This article presents data from an experiment conducted in China in which the ability of certain purification materials and drinking water decontaminants were tested with water polluted by fallout from nuclear explosions. It is explained that the explosion of nuclear weapons or the dissemination of radioactive agents in a future war may pollute drinking water and water sources, creating a danger to human health. The experimental data indicate that the ''Drinking Water Decontamination and Purification Agent'' (DDPA) has a higher purification effectiveness than the ''Drinking Water Purification Powder'' (DPP) for falloutcontaminated water and /sup 131/I-contaminated water, while the ''Aqueous /sup 131/I Radioactivity Purifier'' (AIRP) has a higher purification effectiveness than DPP for /sup 131/I-contaminated water. DDPA consists of potassium permanganate, ferrous sulfate, ferric sulfate, disodium phosphate, No. 2 activated charcoal, earth, barium hydroxide, alum, and aluminium hydroxychloride. DPP consists of activated charcoal, bentonite, sodium phosphate, silver sulfate and aluminium hydroxychloride. AIRP consists of potassium permanganate, ferrous sulfate, ferric sulfate, disodium phosphate, No. 2 activated charcoal, earth, and aluminium hydroxychloride. It is concluded that the 13 common materials tested are effective in purifying radioactive water. Includes 2 tables.

  10. Characterization of polycyclic aromatic hydrocarbon emissions in the particulate and gas phase from smoldering mosquito coils containing various atomic hydrogen/carbon ratios.

    PubMed

    Yang, Tzu-Ting; Lin, Shaw-Tao; Lin, Tser-Sheng; Chung, Hua-Yi

    2015-02-15

    The polycyclic aromatic hydrocarbon emissions in particulate and gas phases generated from smoldering mosquito coils containing various atomic H/C ratios were examined. Five types of mosquito coils were burned in a test chamber with a total airflow rate of 8.0 L/min at a constant relative humidity and temperature. The concentrations of individual PAHs were determined using the GC/MS technique. Among the used mosquito coils, the atomic H/C ratio ranged from 1.23 to 1.57, yielding total mass, gaseous, and particulate PAH emission factors of 28.17-78.72 mg/g, 26,139.80-35,932.98 and 5735.22-13,431.51 ng/g, respectively. The various partitions of PAHs in the gaseous and particulate phases were in the ranges, 70.26-83.70% and 16.30-29.74% for the utilized mosquito coils. The carcinogenic potency of PAH emissions in the particulate phase (203.82-797.76 ng/g) was approximately 6.92-25.08 times higher than that of the gaseous phase (26.27-36.07 ng/g). Based on the analyses of PAH emissions, mosquito coils containing the lowest H/C ratio, a low oxygen level, and additional additives (i.e., CaCO3) are recommended for minimizing the production of total PAH emission factors and carcinogenic potency.

  11. Accelerator Mass Spectrometric (AMS) Measurements of Plutonium Activity Concentrations and 240Pu/239Pu Atom Ratios In Soil Extracts Supplied by the Carlsbad Environmental Monitoring & Research Center

    SciTech Connect

    Hamilton, T F; Brown, T A; Marchetti, A A; Martinelli, R E; Kehl, S R

    2005-02-28

    Plutonium-239 ({sup 239}Pu) and plutonium-239+240 ({sup 239+240}Pu) activities concentrations and {sup 240}Pu/{sup 239}Pu atom ratios are reported for a series of chemically purified soil extracts received from the Carlsbad Environmental Monitoring & Research Center (CEMRC) in New Mexico. Samples were analyzed without further purification at the Lawrence Livermore National Laboratory (LLNL) using accelerator mass spectrometry (AMS). This report also includes a brief description of the AMS system and internal laboratory procedures used to ensure the quality and reliability of the measurement data.

  12. A review of aerial radiological surveys of Nevada Test Site fallout fields 1951 through 1970

    SciTech Connect

    1987-12-01

    Aerial surveys of offsite fallout radiation fields from the Nevada Test Site began in the early 1950s and continued throughout the above-ground testing period. The results of the aerial surveys were used to support ground data in determining the extent of the fallout patterns. For the series of tests conducted in 1953 and 1955, the primary uncertainty of the results was knowing the location of the aircraft. Navigation was made from aeronautical charts of a scale 1:1,000,000, and errors in location of several miles were experienced. Another problem was that exposure rate readings made in the aircraft of 1 milliroentgen per hour or lower were not reliable. Exposure rate measurements above 1 milliroentgen per hour were more accurate, however, and are considered reliable to within a factor of two or three in predicting 3-foot exposure rate levels. For the 1957 series, the aircraft position data were quite accurate. Ground-level exposure rates predicted from aerial data obtained by the United States Geological Survey aircraft for the five-detector array were considered reliable to within +-40% or better for most of the surveys. When the single detector was used, the accuracy decreased to about a factor of two. Relative count rates obtained by the aircraft operated by the Atomic Energy Commission, Raw Materials Division, are probably valid, but quantitative determination of 3-foot exposure rates are not. The Aerial Radiological Monitoring System performed all the aerial surveys in the 1960s. However, the air-to-ground conversion factors used were too low. Using a corrected conversion factor, the predicted 3-foot exposure rates should be valid to +-40% in most fallout fields if all other parameters are considered. 40 refs., 30 figs., 6 tabs.

  13. Mapping the tephra fallout risk: an example from Vesuvius, Italy

    NASA Astrophysics Data System (ADS)

    Barberi, F.; Macedonio, G.; Pareschi, M. T.; Santacroce, R.

    1990-03-01

    THE goal of evaluating the risks related to the reactivation of a quiescent volcano requires the reconstructions of the eruptive history of the volcano, the construction therefrom of a behavioural model of the volcano so as to define the 'maximum expected event9 and the subsequent quantitative models allowing reliable simulation of such an event to be set up and hazard and risk maps to be developed. We have followed this approach to infer the size and character of the explosive eruption of Vesuvius to be expected after a 45-year rest period1,2, and we used a numerical model, tested on the recent Mount St Helens eruption and the Vesuvius eruption in AD 79 3,4, to simulate tephra transport and fallout. By combining the fallout model with a statistical analysis of the wind regime and with the density of urban settlement, we were able to assess quantitatively the tephra fallout risk.

  14. Chlorine atom spin orbit branching ratios and total absolute reaction cross-sections for the H+DCl→HD+Cl reaction

    NASA Astrophysics Data System (ADS)

    Hanf, Alexander; Läuter, Almuth; Suresh, Dhanya; Volpp, Hans-Robert; Wolfrum, Jürgen

    2001-05-01

    Chlorine atom spin-orbit product branching ratios and total absolute reaction cross-sections have been measured for the H+DCl→HD+Cl gas-phase reaction for collision energies of E col=1.0, 1.4 and 1.7 eV. The measured Cl*( 2P1/2) atom spin-orbit product branching ratios φ Cl*(1.0 eV)=[ Cl*]/[ Cl+ Cl*]=(0.06±0.02) , φ Cl*(1.4 eV)=(0.07±0.01) , and φ Cl*(1.7 eV)=(0.16±0.01) revealed the increasing importance of a non-adiabatic reaction channel H+DCl→HD+Cl * with increasing collision energy. The measured total absolute reaction cross-sections allow for comparison with results from recent quasi-classical trajectory (QCT) calculations [F.J. Aoiz et al. J. Phys. Chem. A 104 (2000) 10452].

  15. Fission-fusion correlations for swelling and microstructure in stainless steels: effect of the helium-to-displacement-per-atom ratio

    SciTech Connect

    Odette, G.R.; Maziaz, P.J.; Spitznagel, J.A.

    1981-01-01

    The initial irradiated structural materials data base for fusion applications will be developed in fission reactors. Hence, this data may need to be adjusted using physically-based procedures to represent behavior in fusion environments, viz. - fission-fusion correlations. Such correlation should reflect a sound mechanistic understanding, and be verified in facilities which most closely simulate fusion conditions. In this paper we review the effects of only one of a number of potentially significant damage variables, the helium to displacement per atom ratio, on microstructural evolution in austenitic stainless steels. Dual-ion and helium preinjection data are analyzed to provide mechanistic guidance; these results appear to be qualitatively consistent with a more detailed comparison made between fast (EBR-II) and mixed (HFIR) spectrum neutron data for a single heat of 20% cold-worked 316 stainless steel. These two fission environments bound fusion (He/dpa ratios. A model calibrated to the fission reactor data is used to extrapolate to fusion conditions. Both the theory and broad empirical observation suggest that helium to dpa ratios have both a qualitative and quantitative influence on microstructural evolution; and that the very high and low ratios found in HFIR and EBR-II may not result in behavior which brackets intermediate fusion conditions.

  16. A non-optical real-time particle fallout monitor

    NASA Technical Reports Server (NTRS)

    Chuan, Raymond L.; Bowers, William D.

    1990-01-01

    The paper describes a size-selective fallout monitor that can be employed to assess the degradation of sensitive optical surfaces as well as facilitate the analysis of particle types. The device combines a vertical elutriator and a quartz crystal microbalance, and only particles greater than a specific size can pass through an upward laminar flow generated in the device. The larger particles cause a frequency shift in the crystal oscillator, thereby permitting the measurement of the fallout associated with the contamination of optical instruments.

  17. Seasonal variation of soil-to-plant transfer of K and fallout sup 134,137 Cs in peatland vegetation

    SciTech Connect

    Bunzl, K.; Kracke, W. )

    1989-10-01

    For three plants from a peat bog (Trichophorum caespitosum, Molinia coerulea, Calluna vulgaris) the concentration of 137Cs, the ratio 137Cs:134Cs, and stable K was determined in intervals of about 14 d from June to November 1987. The results show that for two grasses, Trichophorum caespitosum and Molinia coerulea (which have only perennial roots but sprout every year while the old leaves wither), the concentration of 137Cs decreased considerably during the growing season (1800-240, respectively, 4000-320 Bq kg-1 dry weight). A remarkably similar behavior was observed for the seasonal variability of K and radiocesium in the two grass species, which resulted in a nearly constant ratio of 137Cs:K during the year. In contrast, for the evergreen plant Calluna vulgaris (heather) which was contaminated surficially by the Chernobyl fallout, the concentrations of K and 137Cs were rather constant during 1987 (leaves about 10,000; stems about 5000 Bq kg-1 dry weight), even though radiocesium was taken up by the leaves and transported within the plant. For the two grasses, the plant:soil concentration ratios (CR) were obtained separately for total 137Cs, 137Cs from the global fallout, and Chernobyl-derived 137Cs. The CR of 137Cs from the global fallout decreased for Trichophorum caespitosum from 1.9 in the spring to 0.08 in the autumn, and for Chernobyl-derived 137Cs from 1.4 to 0.2. For Molinia coerulea, a similar behavior was observed. Possible reasons for the seasonal variability of the CR values and the different behavior of 137Cs from the global fallout and from the Chernobyl debris are discussed.

  18. The Dose Rate Conversion Factors for Nuclear Fallout

    SciTech Connect

    Spriggs, G D

    2009-02-13

    In a previous paper, the composite exposure rate conversion factor (ECF) for nuclear fallout was calculated using a simple theoretical photon-transport model. The theoretical model was used to fill in the gaps in the FGR-12 table generated by ORNL. The FGR-12 table contains the individual conversion factors for approximate 1000 radionuclides. However, in order to calculate the exposure rate during the first 30 minutes following a nuclear detonation, the conversion factors for approximately 2000 radionuclides are needed. From a human-effects standpoint, it is also necessary to have the dose rate conversion factors (DCFs) for all 2000 radionuclides. The DCFs are used to predict the whole-body dose rates that would occur if a human were standing in a radiation field of known exposure rate. As calculated by ORNL, the whole-body dose rate (rem/hr) is approximately 70% of the exposure rate (R/hr) at one meter above the surface. Hence, the individual DCFs could be estimated by multiplying the individual ECFs by 0.7. Although this is a handy rule-of-thumb, a more consistent (and perhaps, more accurate) method of estimating the individual DCFs for the missing radionuclides in the FGR-12 table is to use the linear relationship between DCF and total gamma energy released per decay. This relationship is shown in Figure 1. The DCFs for individual organs in the body can also be estimated from the estimated whole-body DCF. Using the DCFs given FGR-12, the ratio of the organ-specific DCFs to the whole-body DCF were plotted as a function of the whole-body DCF. From these plots, the asymptotic ratios were obtained (see Table 1). Using these asymptotic ratios, the organ-specific DCFs can be estimated using the estimated whole-body DCF for each of the missing radionuclides in the FGR-12 table. Although this procedure for estimating the organ-specific DCFs may over-estimate the value for some low gamma-energy emitters, having a finite value for the organ-specific DCFs in the table is

  19. Ultrasound-Detected Thyroid Nodule Prevalence and Radiation Dose from Fallout

    PubMed Central

    Land, C. E.; Zhumadilov, Z.; Gusev, B. I.; Hartshorne, M. H.; Wiest, P. W.; Woodward, P. W.; Crooks, L. A.; Luckyanov, N. K.; Fillmore, C. M.; Carr, Z.; Abisheva, G.; Beck, H. L.; Bouville, A.; Langer, J.; Weinstock, R.; Gordeev, K. I.; Shinkarev, S.; Simon, S. L.

    2014-01-01

    Settlements near the Semipalatinsk Test Site (SNTS) in northeastern Kazakhstan were exposed to radioactive fallout during 1949–1962. Thyroid disease prevalence among 2994 residents of eight villages was ascertained by ultrasound screening. Malignancy was determined by cytopathology. Individual thyroid doses from external and internal radiation sources were reconstructed from fallout deposition patterns, residential histories and diet, including childhood milk consumption. Point estimates of individual external and internal dose averaged 0.04 Gy (range 0–0.65) and 0.31 Gy (0–9.6), respectively, with a Pearson correlation coefficient of 0.46. Ultrasound-detected thyroid nodule prevalence was 18% and 39% among males and females, respectively. It was significantly and independently associated with both external and internal dose, the main study finding. The estimated relative biological effectiveness of internal compared to external radiation dose was 0.33, with 95% confidence bounds of 0.09–3.11. Prevalence of papillary cancer was 0.9% and was not significantly associated with radiation dose. In terms of excess relative risk per unit dose, our dose–response findings for nodule prevalence are comparable to those from populations exposed to medical X rays and to acute radiation from the Hiroshima and Nagasaki atomic bombings. PMID:18363427

  20. Ultrasound-detected thyroid nodule prevalence and radiation dose from fallout.

    PubMed

    Land, C E; Zhumadilov, Z; Gusev, B I; Hartshorne, M H; Wiest, P W; Woodward, P W; Crooks, L A; Luckyanov, N K; Fillmore, C M; Carr, Z; Abisheva, G; Beck, H L; Bouville, A; Langer, J; Weinstock, R; Gordeev, K I; Shinkarev, S; Simon, S L

    2008-04-01

    Settlements near the Semipalatinsk Test Site (SNTS) in northeastern Kazakhstan were exposed to radioactive fallout during 1949-1962. Thyroid disease prevalence among 2994 residents of eight villages was ascertained by ultrasound screening. Malignancy was determined by cytopathology. Individual thyroid doses from external and internal radiation sources were reconstructed from fallout deposition patterns, residential histories and diet, including childhood milk consumption. Point estimates of individual external and internal dose averaged 0.04 Gy (range 0-0.65) and 0.31 Gy (0-9.6), respectively, with a Pearson correlation coefficient of 0.46. Ultrasound-detected thyroid nodule prevalence was 18% and 39% among males and females, respectively. It was significantly and independently associated with both external and internal dose, the main study finding. The estimated relative biological effectiveness of internal compared to external radiation dose was 0.33, with 95% confidence bounds of 0.09-3.11. Prevalence of papillary cancer was 0.9% and was not significantly associated with radiation dose. In terms of excess relative risk per unit dose, our dose-response findings for nodule prevalence are comparable to those from populations exposed to medical X rays and to acute radiation from the Hiroshima and Nagasaki atomic bombings.

  1. Long-range volcanic ash transport and fallout during the 2008 eruption of Chaitén volcano, Chile

    NASA Astrophysics Data System (ADS)

    Durant, Adam J.; Villarosa, Gustavo; Rose, William I.; Delmelle, Pierre; Prata, Alfred J.; Viramonte, José G.

    2012-01-01

    The May 2008 eruption of Chaitén volcano, Chile, provided a rare opportunity to measure the long-range transport of volcanic emissions and characteristics of a widely-dispersed terrestrial ash deposit. Airborne ash mass, quantified using thermal infrared satellite remote sensing, ranged between 0.2 and 0.4 Tg during the period 3-7 May 2008. A high level of spatiotemporal correspondence was observed between cloud trajectories and changes in surface reflectivity, which was inferred to indicate ash deposition. The evolution of the deposit was mapped for the first time using satellite-based observations of surface reflectivity. The distal (>80 km) ash deposit was poorly sorted and fine grained, and mean particle size varied very little beyond a distance >300 km. There were three particle size subpopulations in fallout at distances >300 km which mirror those identified in fallout from the 18 May 1980 eruption of Mount St. Helens, known to have a high propensity for aggregation. Discrete temporal sampling and characterisation of fallout demonstrated contributions from specific eruptive phases. Samples collected at the time of deposition were compared to bulk samples collected months after deposition and provided some evidence for winnowing. Experimentally-derived ash leachates had near-neutral pH values and charge balance which indicates minimal quantities of adsorbed acids. X-ray Photoelectron Spectroscopy (XPS) analyses revealed surface enrichments in Ca, Na and Fe and the presence of coatings of mixed Ca-, Na- and Fe-rich salts on ash particles prior to deposition. Low S:Cl ratios in leachates indicate that the eruption had a low S content, and high Cl:F ratios imply gas-ash interaction within a Cl-rich environment. We estimate that ash fallout had potential to scavenge ∼42% of total S released into the atmosphere prior to deposition. XPS analyses also revealed ash particle surfaces were strongly enriched in Fe (in contrast to the results from bulk leachate

  2. Determining Sources and Transport of Nuclear Contamination in Hudson River Sediments with Plutonium, Neptunium, and Cesium isotope ratios

    NASA Astrophysics Data System (ADS)

    Kenna, T. C.; Chillrud, S. N.; Chaky, D. A.; Simpson, H. J.; McHugh, C. M.; Shuster, E. L.; Bopp, R. F.

    2004-12-01

    Different sources of radioactive contamination contain characteristic and identifiable isotopic signatures, which can be used to study sediment transport. We focus on Pu-239, Pu-240, Np-237 and Cs-137, which are strongly bound to fine grained sediments. The Hudson River drainage basin has received contamination from at least three separate sources: 1) global fallout from atmospheric testing of nuclear weapons, which contributed Pu, Np and Cs; 2) contamination resulting from reactor releases at the Indian Point Nuclear Power Plant (IPNPP) located on the Hudson River Estuary ˜70km north of New York Harbor, where records document releases of Cs-137; 3) contamination resulting from activities at the Knolls Atomic Power Laboratory (KAPL) located on the Mohawk River, where incomplete records document releases of Cs-137 but no mention is made of Pu or Np. Here we report measurements of Pu isotopes, Np-237 and Cs-137 for a series of sediment cores collected from various locations within the drainage basin: 1) Mohawk River downstream of KAPL, 2) Hudson River upstream of its confluence with the Mohawk River, and 3) lower Hudson River at a location in close proximity to IPNPP. In addition, we present data from selected samples from two other lower Hudson River locations: One site located ˜30km downstream of IPNPP and another ˜30km upstream of IPNPP. By comparing the isotopic ratios Pu-240/Pu-239, Np-237/Pu-239, and Cs-137/Pu-239, measured in fluvial sediments to mean global fallout values, it is possible to identify and resolve different sources of non-fallout contamination. To date, isotopic data for sediments indicate non-fallout sources of Pu-239, Pu-240, and Cs-137; Np-237, however, appears to originate from global fallout only. Mohawk River sediments downstream of KAPL exhibit enrichments in Pu-239, Pu-240, and Cs-137 that are 7 to 20 times higher than levels expected from global fallout as indicated from Np-237. The elevated levels, non-fallout isotopic signatures

  3. Tailoring Microwave-Absorption Properties of Co x Ni y Alloy/RGO Nanocomposites with Tunable Atomic Ratios

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoqin; Bai, Zhongyi; Zhao, Biao; Zhang, Rui; Chen, Jingbo

    2017-04-01

    Co x Ni y nanoparticles anchored on reduced graphene oxide (rGO) composites with different Co(0)/Ni(0) ratios were successfully prepared by a simple hydrothermal method. The morphology, structure, and magnetic and microwave electromagnetic properties of Co x Ni y /rGO composites were characterized by the x-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, Raman spectroscopy and a vector network analyzer. The Co x Ni y /rGO composites exhibited enhanced microwave absorption properties, which are attributed to the effective complementarities between dielectric loss and magnetic loss. For the Co3Ni1/rGO composite, the minimum reflection loss (RLmin) is -44.89 dB at 12.22 GHz with absorber thickness of 2.5 mm, and the effective absorption bandwidth of the reflection loss (RL) <-10 dB (indicating 90% attenuation) could achieve 5.61 GHz. It is believed that the Co3Ni1/rGO composite may be a promising candidate as a microwave absorber with the features of low density, strong absorption, wide band and low thickness.

  4. Tailoring Microwave-Absorption Properties of Co x Ni y Alloy/RGO Nanocomposites with Tunable Atomic Ratios

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoqin; Bai, Zhongyi; Zhao, Biao; Zhang, Rui; Chen, Jingbo

    2016-11-01

    Co x Ni y nanoparticles anchored on reduced graphene oxide (rGO) composites with different Co(0)/Ni(0) ratios were successfully prepared by a simple hydrothermal method. The morphology, structure, and magnetic and microwave electromagnetic properties of Co x Ni y /rGO composites were characterized by the x-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, Raman spectroscopy and a vector network analyzer. The Co x Ni y /rGO composites exhibited enhanced microwave absorption properties, which are attributed to the effective complementarities between dielectric loss and magnetic loss. For the Co3Ni1/rGO composite, the minimum reflection loss (RLmin) is -44.89 dB at 12.22 GHz with absorber thickness of 2.5 mm, and the effective absorption bandwidth of the reflection loss (RL) <-10 dB (indicating 90% attenuation) could achieve 5.61 GHz. It is believed that the Co3Ni1/rGO composite may be a promising candidate as a microwave absorber with the features of low density, strong absorption, wide band and low thickness.

  5. Gamma-ray thermoluminescence measurements: a record of fallout deposition in Hiroshima?

    PubMed

    Egbert, Stephen D; Kerr, George D

    2012-05-01

    In certain Hiroshima neighborhoods, radiation measurements using thermoluminescence dosimetry (TLD) exceed what can be explained by the initial gamma-ray doses and uncertainties from the Dosimetry System 2002 (DS02). This problem was not previously recognized as being isolated to certain parts of that city. The ratio between TLD measurements and DS02 dose calculations for gamma rays appear to grow larger than unity up to more than three with increasing ground range, but closer examination shows the excess TLD dose (0.1, 0.2, or possibly up to 0.8 Gray) is correlated with certain neighborhoods and could be due to radioactive fallout. At Nagasaki, the TLD measurements do not show this same excess, probably because there were no TLD measurements taken more than 800 m downwind (eastward) from the Nagasaki hypocenter, so that any small excess TLD dose was masked by larger initial gamma-ray doses of 25-80 Gray in the few downwind samples. The DS02 Report had noted many measurements lower than the DS02 calculation for several Nagasaki TLD samples, independent of ground range. This was explained as being the result of previously unaccounted urban shielding which was observed from Nagasaki pre-bomb aerial photos. However, the Hiroshima excess TLD dose issue was not resolved. If the excess TLD doses at Hiroshima are an indication of fallout, it may be possible to use additional TLD studies to make better estimates of the locations and radiation doses to survivors from the fallout after the bombings at both cities.

  6. Distribution of neptunium and plutonium in New Mexico lichen samples (Usnea arizonica) contaminated by atmospheric fallout

    SciTech Connect

    Oldham, Jr., Warren J.; Hanson, Susan K.; Lavelle, Kevin B.; Miller, Jeffrey L.

    2015-08-30

    In this study, the concentrations of 237Np, 239Pu and 240Pu were determined in lichen samples (Usnea arizonica) that were collected from ten locations in New Mexico between 2011 and 2013 using isotope dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS). The observed isotopic ratios for 237Np/239Pu and 240Pu/239Pu indicate trace contamination from global and regional fallout (e.g. Trinity test and atmospheric testing at the Nevada Test Site). The fact that actinide contamination is detected in recent lichen collections suggests continuous re-suspension of fallout radionuclides even 50 years after ratification of the Limited Test Ban Treaty.

  7. L subshell fluorescence cross-sections and relative intensity ratios of some elements in the atomic range 72⩽ Z⩽92

    NASA Astrophysics Data System (ADS)

    Gürol, A.; Karabulut, A.

    2003-08-01

    The Lα 1,2, Lγ 1, Lγ 2,3,6,8, Lγ 4,4' and Lγ 5 X-ray fluorescence cross-sections for some elements in the atomic range 72⩽ Z⩽92 were measured at 59.54 keV. L subshell fluorescence cross-sections (σ L1, σ L2 and σ L3) and relative intensity ratios (σ L1/σ L2, σ L1/σ L3 and σ L2/σ L3) were determined by using these experimental results. In addition, these cross-sections and relative intensity ratios were calculated theoretically. These experimental and theoretical relative intensity ratios were compared with each other and a fairly good agreement between these experimental and theoretical results were found. Besides, our results for L subshell fluorescence cross-sections were compared with the values of Şahin et al. (J. Phys. B 33 (2000) 93). Good agreement between these values was found for σ L3, but there is no agreement for σ L1 and σ L2.

  8. Radioactive fallout in Norway from atmospheric nuclear weapons tests.

    PubMed

    Bergan, Tone D

    2002-01-01

    Historical data on radioactivity in air and precipitation samples have been collected and analysed from study sites in Norway. The purpose of the study was to investigate the correlation between air concentration, precipitation and deposition, and identify areas with high deposition. Areas with high precipitation have been compared with monitoring stations in other countries. The base line data contain measurements of total beta in air and precipitation on a daily basis for the period 1956-1982. Radioactive fallout correlated strongly with annual precipitation which varies from 280 to 4200mm per year in Norway. The deposition of 137Cs was calculated to be 3.23+/-1.20kBq/m2 per 1,000 mm precipitation for the period 1955-1975. Also, the relationship between total beta and 137Cs has been investigated, in order to estimate the age of fallout. The age of fallout in Norway ranges from 3 to 9 months during the test periods, which is considerably shorter than the global average, where the mean residence time for debris in the lower stratosphere is estimated to be 1.3 years. There is no evidence of local fallout from tests on Novaya Zemlya reaching Norwegian areas.

  9. Radioactive fallout from the Chernobyl nuclear reactor accident

    SciTech Connect

    Beiriger, J.M.; Failor, R.A.; Marsh, K.V.; Shaw, G.E.

    1987-08-01

    This report describes the detection of fallout in the United States from the Chernobyl nuclear reactor accident. As part of its environmental surveillance program, Lawrence Livermore National Laboratory maintained detectors for gamma-emitting radionuclides. Following the reactor accident, additional air filters were set out. Several uncommon isotopes were detected at the time the plume passed into the US. (TEM)

  10. Mars - Experimental study of albedo changes caused by dust fallout

    NASA Technical Reports Server (NTRS)

    Wells, E. N.; Veverka, J.; Thomas, P.

    1984-01-01

    A laboratory apparatus was used to simulate the uniform fallout and deposition of particles 1 to 5 microns in diameter in an experimental study on how the spectral and photometric properties of representative Martian areas are affected by fallout of atmospheric dust (smaller than or equalling 60 microns) suspended during dust storms. In this study, measurements are made in the changes in reflectance at optical and near-infrared wavelengths (0.4 to 1.2 micron) caused by deposition of varying amounts of a Mars-analog dust on bright and dark substrates before and after deposition of 6 x 10 to the -5th to 1.5 x 10 to the -3rd g/sq cm of simulated fallout. It is believed that only small amounts of dust particles (approximately 3 x 10 to the -4th g/sq cm) are needed to make significant albedo changes in dark areas of Mars, and that this would rule out uniform dust deposition on the surface of the planet. Data also indicate that other high albedo features like bright crater-related wind streaks may not be areas of significant sediment deposits. Laboratory simulations have permitted estimates of how much the reflectance of an area on Mars would change given a certain amount of dust fallout (g/sq cm) or reflectance data. These simulations may also be useful in tracking the transport and deposition of the dust.

  11. National Fallout Shelter Design Competition. Community Center. Awards

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    Award winning designs for dual-use fallout shelters are presented, representing contributions by the design professions toward development of the national defense resource. The focus and concept of the competition is described as the basis for judging. The nature of dual-use shelter is discussed, which contributes to understanding of the…

  12. Dynamic Monitoring of Cleanroom Fallout Using an Air Particle Counter

    NASA Technical Reports Server (NTRS)

    Perry, Radford

    2011-01-01

    The particle fallout limitations and periodic allocations for the James Webb Space Telescope are very stringent. Standard prediction methods are complicated by non-linearity and monitoring methods that are insufficiently responsive. A method for dynamically predicting the particle fallout in a cleanroom using air particle counter data was determined by numerical correlation. This method provides a simple linear correlation to both time and air quality, which can be monitored in real time. The summation of effects provides the program better understanding of the cleanliness and assists in the planning of future activities. Definition of fallout rates within a cleanroom during assembly and integration of contamination-sensitive hardware, such as the James Webb Space Telescope, is essential for budgeting purposes. Balancing the activity levels for assembly and test with the particle accumulation rate is paramount. The current approach to predicting particle fallout in a cleanroom assumes a constant air quality based on the rated class of a cleanroom, with adjustments for projected work or exposure times. Actual cleanroom class can also depend on the number of personnel present and the type of activities. A linear correlation of air quality and normalized particle fallout was determined numerically. An air particle counter (standard cleanroom equipment) can be used to monitor the air quality on a real-time basis and determine the "class" of the cleanroom (per FED-STD-209 or ISO-14644). The correlation function provides an area coverage coefficient per class-hour of exposure. The prediction of particle accumulations provides scheduling inputs for activity levels and cleanroom class requirements.

  13. The branching ratio between reaction and relaxation in the removal of H2O from its |04>- vibrational state in collisions with H atoms

    NASA Astrophysics Data System (ADS)

    Barnes, Peter W.; Sims, Ian R.; Smith, Ian W. M.; Lendvay, György; Schatz, George C.

    2001-09-01

    The removal of H2O molecules from their |04>- vibrational state in collisions with H atoms can occur both by reaction, producing OH(v=0)+H2, and by nonreactive relaxation. We report an experimental measurement of the fraction (freac) that occurs by reaction. The value of freac is determined by comparing the yields of OH from three experiments in which the same concentration of H2O(|04>-) is prepared by overtone absorption of pulsed laser radiation and OH(v=0) is produced: (i) solely by the H+H2O(|04>-) reaction; (ii) solely by the photodissociation of H2O(|04>-) at 266 nm; and (iii) both by the photodissociation of H2O(|04>-) and by the subsequent reaction of a fraction of the remaining H2O(|04>-) with H atoms. Analysis of these experiments shows that freac=(0.34±0.11). The experimental results are compared with the results of two kinds of scattering calculations performed on a potential energy surface developed recently, specifically with this problem in mind. Using the vibrational coupled-channel infinite-order-sudden (VCC-IOS) method, rate coefficients have been calculated for individual vibrationally inelastic processes and then summed to find the rate coefficient (krelaxH) for total nonreactive relaxation from the |04>- state. The quasiclassical trajectory (QCT) method has been used to calculate the rate coefficient (kreac) for reaction between H atoms and H2O(|04>-). Both the calculated rate coefficient (i.e., krelaxH+kreac) for total loss from H2O(|04>-) and the calculated branching ratio, freac=kreac/(krelaxH+kreac)=0.38, are in quite good agreement with the experimental values.

  14. Atomic data from the Iron Project. XLIV. Transition probabilities and line ratios for Fe VI with fluorescent excitation in planetary nebulae

    NASA Astrophysics Data System (ADS)

    Chen, Guo Xin; Pradhan, Anil K.

    2000-11-01

    Relativistic atomic structure calculations for electric dipole (E1), electric quadrupole (E2) and magnetic dipole (M1) transition probabilities among the first 80 fine-structure levels of Fe VI, dominated by configurations 3d3, 3d24s, and 3d24p, are carried out using the Breit-Pauli version of the code SUPERSTRUCTURE. Experimental energies are used to improve the accuracy of these transition probabilities. Employing the 80-level collision-radiative (CR) model with these dipole and forbidden transition probabilities, and Iron Project R-matrix collisional data, we present a number of [Fe VI] line ratios applicable to spectral diagnostics of photoionized H II regions. It is shown that continuum fluorescent excitation needs to be considered in CR models in order to interpret the observed line ratios of optical [Fe VI] lines in planetary nebulae NGC 6741, IC 351, and NGC 7662. The analysis leads to parametrization of line ratios as function of, and as constraints on, the electron density and temperature, as well as the effective radiation temperature of the central source and a geometrical dilution factor. The spectral diagnostics may also help ascertain observational uncertainties. The method may be generally applicable to other objects with intensive background radiation fields, such as novae and active galactic nuclei. The extensive new Iron Project radiative and collisional calculations enable a consistent analysis of many line ratios for the complex iron ions. The complete tables of transition probabilities are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html.

  15. Lead-210 and Beryllium-7 fallout rates on the southeastern coast of Brazil.

    PubMed

    Sanders, Christian J; Smoak, Joseph M; Cable, Peter H; Patchineelam, Sambasiva R; Sanders, Luciana M

    2011-12-01

    Total ²¹⁰Pb and ⁷Be fallout rates were measured on the coastal region of Niteroi, Brazil. The monthly depositional flux of ²¹⁰Pb and ⁷Be varied by a factor of 26, from 1.7 to 43.3 mBq cm⁻² year⁻¹ and ∼27, from 7.5 to 203.5 mBq cm⁻² year⁻¹, respectively. The relatively large oscillations in the depositional flux of ²¹⁰Pb at this study site were likely due to variations in air mass sources, while the ⁷Be fluctuations may be driven by a combination of weather conditions. Local geology could support the periodic high fluxes of ²¹⁰Pb from continental air masses, as shifting oceanic wind sources were affirmed by the uncorrelated ²¹⁰Pb and ⁷Be fallout activities and ⁷Be/²¹⁰Pb ratios. The ²¹⁰Pb atmospheric deposition was found to be in agreement with local sediment inventories, an important consideration in geochemical studies that estimate sedimentation processes.

  16. Long-term and long-range migration of radioactive fallout in a Karst system.

    PubMed

    Froidevaux, Pascal; Steinmann, Philipp; Pourcelot, Laurent

    2010-11-15

    Mountainous areas are often covered by little evolved soils from which deposited radionuclides can potentially leak into the vadose zone. In the Swiss Jura mountains, we observed unusual isotopic ratios of nuclear weapon test (NWTs) fallout with an apparent loss of NWTs plutonium relative to ¹³⁷Cs of Chernobyl origin in thinner soils. Here, we studied the karstic watershed of a vauclusian spring to determine the residence times of plutonium, ²⁴¹Am, and ⁹⁰Sr deposited by global fallout and their respective mobility in carbonaceous soils. The results show that ⁹⁰Sr is washed most efficiently from the watershed with a residence time of several hundred years. The estimated plutonium residence time is more than 10 times higher (in the range of 5000-10,000 years), and the ²⁴¹Am residence time is double that of plutonium. The spring water ²⁴¹Am/²³⁹+²⁴⁰Pu isotopic ratio is lower (0.12 - 0.28) than found in watershed soils (0.382 ± 0.077). Similar differences are found in aquatic mosses (²⁴¹Am/²³⁹+²⁴⁰Pu isotopic ratio 0.05-0.12), which are permanently submerged in spring waters. In contrast to plutonium, ⁹⁰Sr is leached from these mosses with 0.5M HCl, demonstrating that strontium is probably associated with calcium carbonate precipitations on the mosses. The higher plutonium to americium isotopic ratio found in the samples of spring water and mosses at the outlet of the karst shows that plutonium mobility is enhanced.

  17. Childhood Thyroid Radioiodine Exposure and Subsequent Infertility in the Intermountain Fallout Cohort

    PubMed Central

    Stone, Mary Bishop; Lyon, Joseph L.; VanDerslice, James A.; Alder, Stephen C.

    2012-01-01

    Background: Above-ground and underground nuclear weapon detonation at the Nevada Test Site (1951–1992) has resulted in radioiodine exposure for nearby populations. Although the long-term effect of environmental radioiodine exposure on thyroid disease has been well studied, little is known regarding the effect of childhood radioiodine exposure on subsequent fertility. Objectives: We investigated early childhood thyroid radiation exposure from nuclear testing fallout (supplied predominantly by radioactive isotopes of iodine) and self-reported lifetime incidence of male or female infertility or sterility. Methods: Participants were members of the 1965 Intermountain Fallout Cohort, schoolchildren at the time of exposure who were reexamined during two subsequent study phases to collect dietary and reproductive histories. Thyroid radiation exposure was calculated via an updated dosimetry model. We used multivariable logistic regression with robust sandwich estimators to estimate odds ratios for infertility, adjusted for potential confounders and (in separate models) for a medically confirmed history of thyroid disease. Results: Of 1,389 participants with dosimetry and known fertility history, 274 were classified as infertile, including 30 classified as sterile. Childhood thyroid radiation dose was possibly associated with infertility [adjusted odds ratio (AOR) = 1.17; 95% CI: 0.82, 1.67 and AOR = 1.35; 95% CI: 0.96, 1.90 for the middle and upper tertiles vs. the first tertile of exposure, respectively]. The odds ratios were attenuated (AOR = 1.08; 95% CI: 0.75, 1.55 and AOR = 1.29; 95% CI: 0.91, 1.83 for the middle and upper tertiles, respectively) after adjusting for thyroid disease. There was no association of childhood radiation dose and sterility. Conclusion: Our findings suggest that childhood radioiodine exposure from nuclear testing may be related to subsequent adult infertility. Further research is required to confirm this. PMID:23099433

  18. A survey of radioactive fallout data in Alaska

    SciTech Connect

    DePhillips, M.P.

    1995-10-23

    Considerable attention has been directed by the scientific community to assessing the levels and fate of radionuclides in Arctic ecosystems. The following text and tables present available data and discussion of radionuclide fallout in Alaska. A literature search of 23 on-line databases (Table 1) using Alaska, Strontium (Sr), Cesium (Cs), Plutonium (Pu) and Radionuclide as constraint terms responded with 177 possible citations. After eliminating duplicate citations, 31 articles were available: 17 were relevant to the subject matter; the remainder addressed geologic issues. All of the cited literature addressed {sup 137}Cs, {sup 90}Sr and {sup 239,240}Pu as a result of radionuclide fallout from nuclear testing or accidental release.

  19. Radioecological indexes of fallout measurements from the Fukushima nuclear accident

    NASA Astrophysics Data System (ADS)

    Manolopoulou, Metaxia; Stoulos, Stylianos; Ioannidou, Alexandra; Vagena, Eleni

    2014-05-01

    Fallout from the Fukushima nuclear accident has been monitored for about 1 month in Thessaloniki, Northern Greece. Three different radionuclides, one short-lived, one relatively long-lived and one long- lived fission product were identified in air, grass and milk samples. The 131I, 137Cs and 134Cs activity concentrations in air reached 497, 145 and 126 μBqm-3, respectively on 4 April, 2011. These radionuclides are of particular concern regarding their transfer from the environment to population through the ingestion pathways for the assessment of the Fukushima accident consequences. Radioecological indexes (eco-indexes) of fallout measurements in the air-grass-cow-milk-man pathway for 131I were determined, as they are related to radiological impact of the Fukushima derived radionuclides on the public and environment.

  20. DETECTION AND QUANTITATION OF FALLOUT PARTICLES IN A HUMAN LUNG.

    PubMed

    WEGST, A V; PELLETIER, C A; WHIPPLE, G H

    1964-02-28

    Portions of an adult human lung were studied by autoradiography in order to detect the presence of fallout particles. The radioactivity in the remainder of the tissue was determined with a gamma-ray spectrometer. Four particles were found and their activities were determined. From the measurement for total-fission-product activity in the lung tissue it was calculated that there were approximately 264 particles in the right lung at the time of death.

  1. Web-Enabled Optoelectronic Particle-Fallout Monitor

    NASA Technical Reports Server (NTRS)

    Lineberger, Lewis P.

    2008-01-01

    A Web-enabled optoelectronic particle- fallout monitor has been developed as a prototype of future such instruments that (l) would be installed in multiple locations for which assurance of cleanliness is required and (2) could be interrogated and controlled in nearly real time by multiple remote users. Like prior particle-fallout monitors, this instrument provides a measure of particles that accumulate on a surface as an indication of the quantity of airborne particulate contaminants. The design of this instrument reflects requirements to: Reduce the cost and complexity of its optoelectronic sensory subsystem relative to those of prior optoelectronic particle fallout monitors while maintaining or improving capabilities; Use existing network and office computers for distributed display and control; Derive electric power for the instrument from a computer network, a wall outlet, or a battery; Provide for Web-based retrieval and analysis of measurement data and of a file containing such ancillary data as a log of command attempts at remote units; and Use the User Datagram Protocol (UDP) for maximum performance and minimal network overhead.

  2. Investigation of food contamination since the Chernobyl fallout in Austria.

    PubMed

    Schwaiger, M; Mueck, K; Benesch, T; Feichtinger, J; Hrnecek, E; Lovranich, E

    2004-01-01

    In a large-scale investigation the decrease of the activity concentration of 137Cs in foodstuffs after the widespread Chernobyl fallout was determined. At different times after the deposition in 1986 more than 1000 samples of various foodstuffs in Austria were taken and investigated with regard to their activity concentration. The investigation showed that in the first year after deposition, the activity concentration decreased to about 6-10% (milk, fruit), and 3-6%, respectively (grain, potatoes, vegetables) of the values in the fallout maximum. The calculated effective half-lives are significantly shorter than observed after nuclear weapon test series and result in a smaller long-term exposure than estimated before. The effective ingestion dose in the 50 years following of a one-time nuclear fallout amounts to about 1.3 times of the first year ingestion dose. In 2002, the ingestion dose in Austria amounts to 2.24 microSv (adult), or 0.88 microSv (5-year infant) respectively, which is less than 0.5% of the ingestion dose of the first year and amounts to 0.7% of the ingestion dose from natural radionuclides.

  3. Thyroid neoplasia in Marshall Islanders exposed to nuclear fallout

    SciTech Connect

    Hamilton, T.E.; van Belle, G.; LoGerfo, J.P.

    1987-08-07

    We studied the risk of thyroid neoplasia in Marshall Islanders exposed to radioiodines in nuclear fallout from the 1954 BRAVO thermonuclear test. We screened 7266 Marshall Islanders for thyroid nodules; the islanders were from 14 atolls, including several southern atolls, which were the source of the best available unexposed comparison group. Using a retrospective cohort design, we determined the prevalence of thyroid nodularity in a subgroup of 2273 persons who were alive in 1954 and who therefore were potentially exposed to fallout from the BRAVO test. For those 12 atolls previously thought to be unexposed to fallout, the prevalence of thyroid nodules ranged from 0.9% to 10.6%. Using the distance of each atoll from the test site as a proxy for the radiation dose to the thyroid gland, a weighted linear regression showed an inverse linear relationship between distance and the age-adjusted prevalence of thyroid nodules. Distance was the strongest single predictor in logistic regression analysis. A new absolute risk estimate was calculated to be 1100 excess cases/Gy/y/1 X 10(6) persons (11.0 excess cases/rad/y/1 million persons), 33% higher than previous estimates. We conclude that an excess of thyroid nodules was not limited only to the two northern atolls but extended throughout the northern atolls; this suggests a linear dose-response relationship.

  4. THE DEVELOPMENT OF RADIOACTIVE GLASS SURROGATES FOR FALLOUT DEBRIS

    SciTech Connect

    Martha R. Finck; Leigh R. Martin; Russel R. Lewis; Kevin P. Carney; Christopher A. McGrath

    2014-01-01

    The production of glass that emulates fallout is desired for the nuclear forensics community for training and measurement exercises. The composition of nuclear fallout is complex varying isotopic compositions . As the gaseous cloud traverses from hotter to cooler regions of the atmosphere, the processes of condensation and nucleation entrain environmental materials, vaporized nuclear materials and fission products. The elemental and isotopic composition of the fission products is altered due to chemical fractionation (i.e. the fission product composition that would be expected from fission of the original nuclear material is altered by differences in condensation rates of the elements); the fallout may be enriched or depleted in volatile or refractory fission products. This work describes preliminary results to synthesize, irradiate and fractionate the fission product content of irradiated particulate glass using a thermal distillation two hours after irradiation. The glass was synthesized using a solution-based polymerization of tetraethyl orthosilicate. Uranium was incorporated into the glass particulate at trace concentrations during polymerization. The particulate was subjected to a short thermal neutron irradiation then heated to 1273 K approximately 2 hours after the end of irradiation. Fission products of 133, 134, 135I, 132, 134Te, 135Xe, 138Cs and 91, 92Sr were observed to be distilled from the particulate. The results of these preliminary studies are discussed.

  5. {sup 36}Cl bomb fallout at mid latitudes

    SciTech Connect

    Synal, H.A.; Beer, J.; Gaeggeler, H.

    1995-12-01

    Large amounts of {sup 36}Cl have been produced during the atmospheric test of nuclear weapons in the late fifties and early sixties. During this time the {sup 36}Cl fallout was about three orders of magnitudes larger than during previous times. The well defined {sup 36}Cl pulse has a great potential for hydrological investigations, especially as a tracer for groundwater studies. Detailed measurements of bomb produced {sup 36}Cl were carried out earlier on ice cores from Dye-3 (Greenland). To adopt the {sup 36}Cl pulse measured in Greenland as an input function to other locations its latitude dependence has to be known. So far, atmospheric transport models and the measured distribution of {sup 90}Sr and {sup 137}Cs fallout are used to estimate the latitude dependence of meteoric and bomb produced {sup 36}Cl fallout. In this contribution, {sup 36}Cl measurements on an ice core from an Alpine Glacier (Fiescher Horn, Switzerland) are presented. The results are compared with earlier measurements from a Greenland ice core and implications for the global {sup 36}Cl transport are discussed.

  6. Photoelectron spectroscopy of O{sup -} at 266 nm: Ratio of ground- and excited-state atomic oxygen production and channel-resolved photoelectron anisotropy parameters

    SciTech Connect

    Domesle, C.; Jordon-Thaden, B.; Wolf, A.; Lammich, L.; Pedersen, H. B.; Foerstel, M.; Hergenhahn, U.

    2010-09-15

    The photodetachment dynamics of the atomic oxygen anion O{sup -} has been investigated at 266 nm (4.67 eV) by photoelectron detection in a crossed-beam experiment using a magnetic-bottle electron spectrometer. Taking explicit advantage of the Doppler shift imposed by the moving ion beam on the photoelectron energies, we report both the final-state branching ratio and photoelectron angular distributions. After photoabsorption at 266 nm, the formed electron-oxygen scattering state disintegrates, forming either the excited {sup 1}D or the ground {sup 3}P state of oxygen with a partition of {sup 1}D:{sup 3}P=0.32 {+-} 0.06. The detachment leading to the production of O({sup 3}P) shows an angular distribution of photoelectrons characterized by {beta}{sub P}=0.00 {+-} 0.10 mimicking a pure s-wave detachment, while the detachment into excited O({sup 1}D) occurs with {beta}{sub D}=-0.90{+-}0.10, giving direct evidence of interference between the outgoing s and d waves.

  7. Electrons per atom ratio determination and Hume-Rothery electron concentration rule for P-based polar compounds studied by FLAPW-fourier calculations.

    PubMed

    Mizutani, Uichiro; Sato, Hirokazu; Inukai, Manabu; Nishino, Yoichi; Zijlstra, Eeuwe Sieds

    2015-02-02

    The extent to which reliable electrons per atom ratio, e/a, are determined and the validity of the Hume-Rothery stabilization mechanism are ensured upon increasing ionicity are studied by applying first-principles full potential linearized augmented plane wave (FLAPW)-Fourier band calculations to as many as 59 binary compounds formed by adding elements from periods 2-6 to phosphorus in group 15 of the Periodic Table. Van Arkel-Ketelaar triangle maps were constructed both by using the Allen electronegativity data and by using an energy difference between the center-of-gravity energies of FLAPW-derived s and p partial densities of states (DOSs) for the equiatomic compounds studied. The determination of e/a and the test of the interference condition, both of which play a key role in the Hume-Rothery stabilization mechanism, were reliably made for all intermetallic compounds, as long as the ionicity is less than 50%. In the A-P (A = Li, Na, K, Rb, and Cs) compounds with ionicity exceeding 50%, however, e/a determination becomes unstable, as reflected in its P concentration dependence. New Hume-Rothery electron concentration rules were theoretically found in two families of polar compounds: skutterudite compounds TMP(3), TMAs(3), and TMSb(3) (TM = Co, Ni, Rh, and Ir; cI32) with e/a = 4.34 and TM(3)P (TM = Cr, Mn, Fe, and Ni; tI32) with e/a = 2.20.

  8. Effect of sputtering power on Cd/Zn atomic ratio and optical properties of Cu2ZnxCd1-xSnS4 thin films deposited by magnetron sputtering: An experimental and first-principle study

    NASA Astrophysics Data System (ADS)

    Xu, Na; Li, Pingting; Hao, Yunxing; Wang, Xin; Meng, Lei

    2016-09-01

    Cu2ZnxCd1-xSnS4 (CZCTS) thin films were deposited on soda-lime glass (SLG) substrates by rf magnetron sputtering. It is found that the Cd/Zn atomic ratio of kesterite CZCTS increases with the enhancement of sputtering power. The structural, surface morphology and optical properties of the CZCTS thin films deposited at different sputtering power were systemically investigated. The X-ray diffraction (XRD) measurements indicate that all CZCTS thin films are polycrystalline with kesterite structure and no impurity phase is observed. The variation of Cd/Zn atomic ratio in CZCTS results in the shift of the optical bandgap.

  9. Urinary excretion of radionuclides from Marshallese exposed to fallout from the 1954 Bravo nuclear test.

    PubMed

    Harris, Payne S; Simon, Steven L; Ibrahim, Shawki A

    2010-08-01

    Soon after the Bravo nuclear test at Bikini Atoll in the Marshall Islands on 1 March 1954, urine samples were collected for analysis of excreted radioactivity from native residents exposed to radioactive fallout on two atolls as well as from U.S. military personnel on a third atoll. The earliest acquired samples, obtained by the Los Alamos Scientific Laboratory (LASL), were assayed for various radionuclides and provided the first known measurements of (131)I in urine following exposure to fallout from a nuclear test. Over the course of 1954, many additional samples were collected by the LASL, as well as by the Atomic Energy Commission New York Operations Office's Health and Safety Laboratory and the Naval Radiological Defense Laboratory. Collectively, the groups sampled included Marshallese exposed on Rongelap and Ailinginae Atolls, American military weather observers temporarily resident on Rongerik Atoll, and sailors from the Japanese fishing vessel, the Lucky Dragon. While the bioassay measurement data and individual urine volumes have been crucial to various attempts to assess intakes of radioactivity and the related internal radiation doses among the Marshallese, those data have never been published in any peer-reviewed journal, but have been restricted to agency memoranda, laboratory reports, and summaries in some publications and book chapters. Reconstructions of internal doses to Marshallese in 1954 and in later years have depended on these data and, hence, they have considerable historical importance as well as importance to ongoing health risk projections for Marshallese. This paper presents much of the original data on urine volumes and radioactivity from the various assays of urine for radionuclides, and compares estimates of (131)I intakes made in 1954, 1985, 1987, and 2008.

  10. A simple model to estimate deposition based on a statistical reassessment of global fallout data.

    PubMed

    Pálsson, S E; Howard, B J; Bergan, T D; Paatero, J; Isaksson, M; Nielsen, S P

    2013-07-01

    Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. Monitoring of the resulting global fallout was carried out globally by the Environmental Measurements Laboratory and the UK Atomic Energy Research Establishment as well as at national level by some countries. A correlation was identified between fallout deposition and precipitation and an uneven distribution with latitude. In this study, the available data from 1954 to 1976 for (90)Sr and (137)Cs were reanalysed using analysis of covariance (ANCOVA) and logarithmically transformed values of the monthly deposition density as the response variable. Generalized additive models (GAM) were used to explore the relationship of different variables to the response variable and quantify the explanatory power that could be achieved. The explanatory variables which consistently explained most of the variability were precipitation at each site, latitude and change with time and a simple linear model was produced with similar explanatory power as the GAM. The estimates improved as the temporal resolution of the precipitation data increased. A good log-log fit could be obtained if a bias of about 1-6 mm precipitation per month was added, this could be interpreted as dry deposition which is not otherwise accounted for in the model. The deposition rate could then be explained as a simple non-linear power function of the precipitation rate (r(0.2-0.6) depending on latitude band). A similar non-linear power function relationship has been the outcome of some studies linking wash-out and rain-out coefficients with rain intensity. Our results showed that the precipitation rate was an important parameter, not just the total amount. The simple model presented here allows the recreation of the deposition history at a site, allowing comparison with time series of activity concentrations for different environmental compartments, which is important for model validation.

  11. URINARY EXCRETION OF RADIONUCLIDES FROM MARSHALLESE EXPOSED TO FALLOUT FROM THE 1954 BRAVO NUCLEAR TEST

    PubMed Central

    Harris, Payne S.; Simon, Steven L.; Ibrahim, Shawki A.

    2014-01-01

    Soon after the Bravo nuclear test at Bikini Atoll in the Marshall Islands on 1 March 1954, urine samples were collected for analysis of excreted radioactivity from native residents exposed to radioactive fallout on two atolls as well as from U.S. military personnel on a third atoll. The earliest acquired samples, obtained by the Los Alamos Scientific Laboratory (LASL), were assayed for various radionuclides and provided the first known measurements of 131I in urine following exposure to fallout from a nuclear test. Over the course of 1954, many additional samples were collected by the LASL, as well as by the Atomic Energy Commission New York Operations Office’s Health and Safety Laboratory and the Naval Radiological Defense Laboratory. Collectively, the groups sampled included Marshallese exposed on Rongelap and Ailinginae Atolls, American military weather observers temporarily resident on Rongerik Atoll, and sailors from the Japanese fishing vessel, the Lucky Dragon. While the bioassay measurement data and individual urine volumes have been crucial to various attempts to assess intakes of radioactivity and the related internal radiation doses among the Marshallese, those data have never been published in any peer-reviewed journal, but have been restricted to agency memoranda, laboratory reports, and summaries in some publications and book chapters. Reconstructions of internal doses to Marshallese in 1954 and in later years have depended on these data and, hence, they have considerable historical importance as well as importance to ongoing health risk projections for Marshallese. This paper presents much of the original data on urine volumes and radioactivity from the various assays of urine for radionuclides, and compares estimates of 131I intakes made in 1954, 1985, 1987, and 2008. PMID:20622553

  12. A Two Step Method to Treat Variable Winds in Fallout Smearing Codes.

    DTIC Science & Technology

    1982-03-01

    fallout contours generated by DELFIC, WSEG and SEER in real winds using a set of hypothetical and real atmospheric nuclear detonations . To compare...Pacific test. AFSWP Fallout Contours The Castle-Bravo nuclear weapon test was detonated in the Bikini Atoll on 4 March 1954. The unexpectedly high fission...predict fallout locations at 6+ hours after detonation is tacitly assuming no temporal or spatial variations in the wind profile. This assumption will intro

  13. Study of twenty-four nationwide fallout patterns from twelve winds. Final report

    SciTech Connect

    Schmidt, L.A.

    1981-09-01

    The research conducted under this contract deals with an assessment of fallout deposition resulting from two different types of attacks on the continental United States (counterforce-only and counterforce plus countervalue) given twelve typical wind patterns - one for each month of the year. Representations of fallout deposition are given in two categories - one accenting higher dose ranges to indicate shelter requirements and the other accenting lower dose ranges to present the complete spectrum of the fallout threat. The research is reported in descriptive presentation of the model, the winds, the attack, and the results. Appendices present the fallout deposition maps.

  14. Multifractal structure of the ¹³⁷Cs fallout at small spatial scales.

    PubMed

    Grubich, A O

    2012-05-01

    Regardless of the surface area of the site, the spatial distribution of radioactive contamination of soils with ¹³⁷Cs for Chernobyl fallout is described by a lognormal distribution. Moreover, the spatial pattern of the radioactive contamination of soil is random geometrical multifractal field. Due to that, any contamination spot, when studied in detail, decomposes into a multitude of small spots decomposing further into a multitude of smaller spots etc. Similar patterns are apparently characteristic for fallout of other radionuclides, the Fukushima fallout, as well as atmospheric fallout of non-radioactive dust and aerosols.

  15. Rate constants and H atom branching ratios of the gas-phase reactions of methylidyne CH(X2Pi) radical with a series of alkanes.

    PubMed

    Loison, Jean-Christophe; Bergeat, Astrid; Caralp, Françoise; Hannachi, Yacine

    2006-12-21

    The reactions of the CH radical with several alkanes were studied, at room temperature, in a low-pressure fast-flow reactor. CH(X2Pi, v = 0) radicals were obtained from the reaction of CHBr(3) with potassium atoms. The overall rate constants at 300 K are (0.76 +/- 0.20) x 10(-10) [Fleurat-Lessard, P.; Rayez, J. C.; Bergeat, A.; Loison, J. C. Chem. Phys. 2002, 279, 87],1 (1.60 +/- 0.60) x 10(-10)[Galland, N.; Caralp, F.; Hannachi, Y.; Bergeat, A.; Loison, J.-C. J. Phys. Chem. A 2003, 107, 5419],2 (2.20 +/- 0.80) x 10(-10), (2.80 +/- 0.80) x 10(-10), (3.20 +/- 0.80) x 10(-10), (3.30 +/- 0.60) x 10(-10), and (3.60 +/- 0.80) x 10(-10) cm3 molecule(-1) s(-1), (errors refer to +/-2sigma) for methane, ethane, propane, n-butane, n-pentane, neo-pentane, and n-hexane respectively. The experimental overall rate constants correspond to those obtained using a simple classical capture theory. Absolute atomic hydrogen production was determined by V.U.V. resonance fluorescence, with H production from the CH + CH4 reaction being used as a reference. Observed H branching ratios were for CH4, 1.00[Fleurat-Lessard, P.; Rayez, J. C.; Bergeat, A.; Loison, J. C. Chem. Phys. 2002, 279, 87];1 C(2)H(6), 0.22 +/- 0.08 [Galland, N.; Caralp, F.; Hannachi, Y.; Bergeat, A.; Loison, J.-C. J. Phys. Chem. A 2003, 107, 5419];2 C(3)H(8), 0.19 +/- 0.07; C(4)H(10) (n-butane), 0.14 +/- 0.06; C(5)H(12) (n-pentane), 0.52 +/- 0.08; C(5)H(12) (neo-pentane), 0.51 +/- 0.08; C(5)H(12) (iso-pentane), 0.12 +/- 0.06; C(6)H(14) (n-hexane), 0.06 +/- 0.04.

  16. Outcome of Transplant-fallout Patients With Unresectable Cholangiocarcinoma

    PubMed Central

    Sio, Terence T.; Haddock, Michael G.; Novotny, Paul J.; Gores, Gregory J.; Alberts, Steven R.; Miller, Robert C.; Heimbach, Julie K.; Rosen, Charles B.

    2016-01-01

    Objectives: The aim of this was to determine survival after starting neoadjuvant therapy for patients who became ineligible for orthotopic liver transplantation (OLT). Methods and Materials: Since January 1993, 215 patients with unresectable cholangiocarcinoma began treatment with planned OLT. Treatment included external-beam radiation therapy (EBRT) with fluorouracil, bile duct brachytherapy, and postradiotherapy fluorouracil or capecitabine before OLT. Adverse findings at the staging operation, death, and other factors precluded OLT in 63 patients (29%), of whom 61 completed neoadjuvant chemoradiation. Results: By October 2012, 56 (89%) of the 63 patients unable to undergo OLT had died. Twenty-two patients (35%) became ineligible for OLT before the staging operation, 38 (60%) at the staging operation, and 3 (5%) after staging. From the date of diagnosis, median overall survival was 12.3 months. Survival was 17% at 18 months and 7% at 24 months. Median survival after fallout was 6.8 months. Median survival after the staging operation was 6 months. Two patients lived for 3.7 and 8.7 years before dying of cancer or liver failure caused by persistent biliary stricture at the site of the original cancer, respectively. Univariate analysis showed that time from diagnosis to fallout correlated with overall survival (P=0.04). Conclusions: In highly selected patients initially suitable for OLT, the mortality rate for cholangiocarcinoma was high in patients who became ineligible for OLT. Their survival, however, was comparable to expected survival for patients with locally advanced or metastatic disease treated with nontransplant therapies. The most common reason for patient fallout was adverse findings at the staging operation. PMID:24921218

  17. Assessment and Control of the Transoceanic Fallout Threat

    DTIC Science & Technology

    1974-08-01

    p pause, H , varies, but for the purpose to be applied here, it can beP assumed to be 17 kilometers above sea level. 6 A set of calculated fallout...Arizona, Connecticut, Delaware, Indiana, Kentucky, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico , Ohio, South Dakota, Tennessee, Virginia...DAKOTAonea MINNESOTA ’-"( .-.. SOUTH DAKOTA ~ IOWA- I S,’" , -- ,S o " ’ u~1 ~-~ .OLORAO / .""ANSAS CAL e 2t.MISOURI * .... OKLAHOMA ’ : NEW MEXICO

  18. Radioactive fallout from the Chernobyl nuclear reactor accident

    SciTech Connect

    Beiriger, J.M.; Failor, R.A.; Marsh, K.V.; Shaw, G.E.

    1987-03-23

    Following the accident at the nuclear reactor at Chernobyl, in the Soviet Union on April 26, 1986, we performed a variety of measurements to determine the level of the radioactive fallout on the western United States. We used gamma-spectroscopy to analyze air filters from the areas around Lawrence Livermore National Laboratory (LLNL), California, and Barrow and Fairbanks, Alaska. Milk from California and imported vegetables were also analyzed. The levels of the various fission products detected were far below the maximum permissible concentration levels.

  19. A Multiburst Fallout Model for Operational Type Studies.

    DTIC Science & Technology

    1981-03-01

    the cloud and f~y~t)= ! e Yt It is obvious from Eq (5) that f (y ,t is a norm:ial function describing the crosswind spread of a single nuclear cloud ...If two or more clouds are in close proximity and merge at some point to become one large cloud , a siingle normal function will no longer account for...horizontal activity; there will be some cumulative effect from each contributing single-burst cloud . The fallout on the ground from this new, large

  20. Indication of the radioactive fallout in Riyadh, Saudi Arabia following the Fukushima nuclear accident.

    PubMed

    Alkhomashi, N; Almasoud, Fahad I

    2016-02-01

    On March 2011, a severe damage has occurred to Fukushima Di-iachi nuclear reactor complex in Japan following the huge earthquake and the resulting Tsunami. Consequently, vast amounts of radioactive fallout were released into the atmosphere and contaminated the environment in Japan. Soon after the accident, traces of anthropogenic radionuclides were detected in environmental samples collected in many parts in the northern hemisphere even very far away from Japan creating a global concern. There is no information about radioactive contamination in the Arabian Peninsula caused by the Japanese Fukushima nuclear accident. The first evidence of Fukushima radioactive fallout in Riyadh (24° 43' N, 46° 38' E), Saudi Arabia has been confirmed in April 8, 2011. The airborne fission products (131)I, (134)Cs and (137)Cs were measured in air samples. The radionuclide concentrations were determined by identifying their characteristic gamma rays using a germanium detector. Their activity concentrations were studied as a function of time over a period of 20 days at the end of which they had mostly fallen below our limit of detection. The maximum activity concentration of (131)I, (134)Cs and (137)Cs in air of, respectively, 323.7 ± 18.5, 17.2 ± 1.0 and 26.0 ± 1.8 μBq m(-3) were observed on April 10-11, 2011. The (131)I/(137)Cs and (134)Cs/(137)Cs activity ratio values in air were presented and discussed. Finally, the effective doses to the public of Riyadh city from inhalation of (131)I, (134)Cs and (137)Cs due to contribution from Fukushima incident was found far below levels of concern.

  1. Federal Guidance Report No. 6: Revised Fallout Estimates for 1964-1965 and Verification of the 1963 Predictions

    EPA Pesticide Factsheets

    The purposes of this report is to compare, make more precise estimates about the predictions made as to the levels of fallout, and evaluate the validity of the prediction procedures when they are applied to a changing fallout situation.

  2. Real-time particulate fallout contamination monitoring technology development at NASA Kennedy Space Center

    NASA Astrophysics Data System (ADS)

    Mogan, Paul A.; Schwindt, Chris J.

    1998-10-01

    Two separate real-time particulate fallout monitoring instruments have been developed by the contamination monitoring Laboratory at NASA John F. Kennedy Space Center. These instruments monitor particular fallout contamination deposition rates in cleanrooms and allow certification of cleanliness levels as well as proactive protection of valuable flight hardware.

  3. A Community Facilities Center with Fallout Shelter as Dual Purpose Space.

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    A presentation is made of five award-winning designs for a fireproof community recreation facility, on a selected site in New York City, incorporating a fallout shelter as a dual-purpose space. Graphic illustrations are given of the award winning designs, each of which used one of the following solutions--(1) the fallout structure above grade with…

  4. Individual human odor fallout as detected by trained canines.

    PubMed

    Vyplelová, Petra; Vokálek, Václav; Pinc, Ludvík; Pacáková, Zuzana; Bartoš, Luděk; Santariová, Milena; Čapková, Zuzana

    2014-01-01

    We tested the hypothesis that if odor fallout (the release of a human's odor onto an untouched object) in human subjects exists, then holding a hand above an absorbent will produce a detectable scent which will be subsequently matched in a detection test by trained canines. Scents were collected from seven males to sterile cotton absorbent squares. The left hand was used to get the control scent and the right hand served as the target scent. Each experimental subject was sitting; his left hand was laid down on a cotton square for 3 min. The right hand was held 5 cm above another cotton square for 3 min. The scent identification was done by two specially trained police German shepherds. These canines had routinely performed scent identification line-ups as part of criminal investigation procedures. Both canines performed 14 line-ups and correctly matched the collected scents of all test subjects. The results suggest the existence of human odor fallout, whereby a human scent trace is left by humans even if they do not touch an object.

  5. Fallout 137Cs in reindeer herders in Arctic Norway.

    PubMed

    Skuterud, Lavrans; Thørring, Håvard

    2015-03-03

    Reindeer herders in the Arctic were among the most heavily exposed populations to the global fallout from nuclear weapons testing in the 1950s and 1960s, due to high transfer of radionuclides in the lichens-reindeer-human food chain. Annual studies of (137)Cs in reindeer herders in Kautokeino, Norway, were initiated in 1965 to monitor radiation doses and follow environmental (137)Cs behavior. The (137)Cs concentrations declined from the peak in 1965 with effective half-times of 6-8 years, only interrupted by a temporary doubling in levels from 1986 to 1987 due to the Chernobyl fallout. During the period of 1950-2010 an average herder received an integrated effective dose from incorporated (137)Cs of about 18 mSv. This dose represents an insignificant increase in the risk for developing cancer. Health studies even show a significantly lower cancer incidence among Sámis and reindeer herders in northern Norway compared to other populations in the same area.

  6. Extracting Information on Tephra Fallout Deposits With Ground Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Kruse, S.; Connor, C.; Martin, K.; Mora, R.; Ramirez, C.; Alvarado, G.

    2005-12-01

    Numerical simulation and inversion of high resolution data on tephra fallout deposits offers an opportunity to fundamentally improve our ability to estimate eruption parameters from deposits. Traditional trenching data is insufficient to adequately constrain eruption parameters. Ground penetrating radar can change this by providing high resolution data along continuous transects, particularly where deposit thickness is too great to trench. Differences between observations and numerical simulations provide details about the physics of volcanic eruptions not captured by current models and provide clues about the limits of current models. Studies on Cerro Negro, Nicaragua and Irazú, Costa Rica demonstrate that GPR is beautifully suited to imaging tephra blankets in both dry and wet environments. Surveys with 100 and 200 MHz antennas show clear reflectors within the tephra fallout sequence are imaged to 20 meters depth. In accord with trench data, we interpret the bright reflectors as weathered horizons (paleosols in some cases) and abrupt changes in grain size that mark intervals between eruptive events. Simulations of radar wave propagation through volcanic deposits are used to examine the conditions under which useful information on weathered horizons and on ballistic dimensions can be extracted.

  7. Fallout computer codes. A bibliographic perspective. Technical report, 1 November 1992-1 September 1993

    SciTech Connect

    Rowland, R.

    1994-07-01

    This report is a summary overview of the basic features and differences among the major radioactive fallout models and computer codes that are either in current use or that form the basis for more contemporary codes and other computational tools. The DELFIC, WSEG-10, KDFOC2, SEER3, and DNAF-1 codes and the EM-1 model are addressed. The review is based only on the information that is available in the general body of literature. This report describes the fallout process, gives an overview of each code/model, summarizes how each code/model handles the basic fallout parameters (initial cloud, particle distributions, fall mechanics, total activity and activity to dose rate conversion, and transport), cites the literature references used, and provides an annotated bibliography for other fallout code literature that was not cited. Nuclear weapons, Radiation, Radioactivity, Fallout, DELFIC, WSEG, Nuclear weapon effects, KDFOC, SEER, DNAF, EM-1.

  8. A perspective on public concerns about exposure to fallout from the production and testing of nuclear weapons.

    PubMed

    Hoffman, F Owen; Apostoaei, A Iulian; Thomas, Brian A

    2002-05-01

    releases and to NTS and global fallout. Information is being requested on individual doses and risks from these cumulative exposures, with estimates of uncertainty, including estimates of the absorbed organ dose (as opposed to the effective dose), the risk of disease incidence as opposed to the risk of a cancer fatality, and the chance that a person's diagnosed disease was caused by past exposure (i.e., the probability of causation). This paper attempts to address some of these concerns. We conclude by noting that many individuals exposed in childhood during the 1950's to 131I in fallout from nuclear weapons production and testing would qualify for compensation and medical care if the present rules for the adjudication of claims for atomic veterans and radiation workers at DOE sites were to be extended to the public.

  9. Anomalous plutonium isotopic ratios in sediments of Lake Qinghai from the Qinghai-Tibetan Plateau, China.

    PubMed

    Wu, Fengchang; Zheng, Jian; Liao, Haiqing; Yamada, Masatoshi; Wan, Guojiang

    2011-11-01

    The vertical profiles of (239+240)Pu and (137)Cs activities and (240)Pu/(239)Pu isotopic ratios are determined for three sediment cores of Lake Qinghai from the Qinghai-Tibetan Plateau, China, and compared with those in sediments of another three lakes (Lakes Bosten, Sugan, and Shuangta), the only existing ones closest to Lop Nor area, China's nuclear weapons test site in the northwestern part of the country. The mean inventory of 47.7 ± 18.7 MBq km(-2) for (239+240)Pu activity in Lake Qinghai is comparable to the average value of global fallout expected at the same latitude, yet the mean inventory of 1112.0 ± 78.0 MBq km(-2) for (137)Cs is slightly lower than that of global fallout. Anomalously low (240)Pu/(239)Pu isotopic ratios (0.038-0.125) were found in the 3-6.5 cm deep sediment layers, indicating the trace Pu input from early nuclear weapons research activities at Atomic City in the lake's watershed during the 1950-60s. Model calculation indicated that the Pu input accounted for approximately 5-16% of the total Pu inventory. The observation of low (240)Pu/(239)Pu ratio in the deep sediment layer provided a new time marker for recent sediment dating in the lake and around the area. The results are of great significance to the further understanding of sources, records, and environmental impacts of global and regional nuclear activities in the environment and provide important chronological information for further studies on the water eutrophication process and climatic change, and reconstruction of pollution history of organic contaminants and heavy metals in the watershed of Lake Qinghai.

  10. The Exposure Rate Conversion Factor for Nuclear Fallout

    SciTech Connect

    Spriggs, G D

    2009-02-11

    Nuclear fallout is comprised of approximately 2000 radionuclides. About 1000 of these radionuclides are either primary fission products or activated fission products that are created during the burn process. The exposure rate one meter above the surface produced by this complex mixture of radionuclides varies rapidly with time since many of the radionuclides are short-lived and decay numerous times before reaching a stable isotope. As a result, the mixture of radionuclides changes rapidly with time. Using a new code developed at the Lawrence Livermore National Laboratory, the mixture of radionuclides at any given point in time can be calculated. The code also calculates the exposure rate conversion factor (ECF) for all 3864 individual isotopes contained in its database based on the total gamma energy released per decay. Based on the combination of isotope mixture and individual ECFs, the time-dependent variation of the composite exposure rate conversion factor for nuclear fallout can be easily calculated. As example of this new capability, a simple test case corresponding to a 10 kt, uranium-plutonium fuel has been calculated. The results for the time-dependent, composite ECF for this test case are shown in Figure 1. For comparison, we also calculated the composite exposure rate conversion factor using the conversion factors found in Federal Guidance Report No.12 (FGR-12) published by ORNL, which contains the conversion factors for approximately 1000 isotopes. As can be noted from Figure 1, the two functions agree reasonably well at times greater than about 30 minutes. However, they do not agree at early times since FGR-12 does not include all of the short-lived isotopes that are produced in nuclear fallout. It should also be noted that the composite ECF at one hour is 19.7 R/hr per Ci/m{sup 2}. This corresponds to 3148 R/hr per 1 kt per square mile, which agrees reasonably well with the value of 3000 R/hr per 1 kt per square mile as quoted by Glasstone. We have

  11. The KFM, A Homemade Yet Accurate and Dependable Fallout Meter

    SciTech Connect

    Kearny, C.H.

    2001-11-20

    The KFM is a homemade fallout meter that can be made using only materials, tools, and skills found in millions of American homes. It is an accurate and dependable electroscope-capacitor. The KFM, in conjunction with its attached table and a watch, is designed for use as a rate meter. Its attached table relates observed differences in the separations of its two leaves (before and after exposures at the listed time intervals) to the dose rates during exposures of these time intervals. In this manner dose rates from 30 mR/hr up to 43 R/hr can be determined with an accuracy of {+-}25%. A KFM can be charged with any one of the three expedient electrostatic charging devices described. Due to the use of anhydrite (made by heating gypsum from wallboard) inside a KFM and the expedient ''dry-bucket'' in which it can be charged when the air is very humid, this instrument always can be charged and used to obtain accurate measurements of gamma radiation no matter how high the relative humidity. The heart of this report is the step-by-step illustrated instructions for making and using a KFM. These instructions have been improved after each successive field test. The majority of the untrained test families, adequately motivated by cash bonuses offered for success and guided only by these written instructions, have succeeded in making and using a KFM. NOTE: ''The KFM, A Homemade Yet Accurate and Dependable Fallout Meter'', was published by Oak Ridge National Laboratory report in1979. Some of the materials originally suggested for suspending the leaves of the Kearny Fallout Meter (KFM) are no longer available. Because of changes in the manufacturing process, other materials (e.g., sewing thread, unwaxed dental floss) may not have the insulating capability to work properly. Oak Ridge National Laboratory has not tested any of the suggestions provided in the preface of the report, but they have been used by other groups. When using these instructions, the builder can verify the

  12. The distribution and history of nuclear weapons related contamination in sediments from the Ob River, Siberia as determined by isotopic ratios of plutonium and neptunium.

    PubMed

    Kenna, T C; Sayles, F L

    2002-01-01

    Isotopic ratios of Pu and Np measured in sediment cores from 5 locations in the Ob River drainage basin show clear evidence of input from sources other than global fallout (non-fallout sources). Historical contaminant records obtained by combining isotopic ratio information with chronological information indicate that non-fallout inputs are from several sources that have varied significantly over the past 50 years. Unique isotopic signatures observed in sediments from tributaries that drain areas containing known or suspected sources of non-fallout contamination are used to identify the source of materials in sediments collected at downstream locations. These data can lead to a better understanding of the transport behavior, fate, and relative importance of particle reactive, weapons related contaminants originating from the nuclear facilities Mayak. Tomsk-7, and Semipalitinsk, which lie within the drainage basin. From our work to date, we draw the following conclusions: (1) Persistent non-fallout contamination is observed in the Ob River above its confluence with the Irtysh River, indicating contamination from the Tomsk-7 facility. (2) Non-fallout contamination in the Tobol River above its confluence with the Irtysh River indicates contamination from the Mayak facility. (3) Non-fallout contamination in the Irtysh River above its confluence with the Tobol River indicates contamination from the Semipalitinsk weapons test site. (4) The occurrence of isotopic ratios in Ob Delta sediments that are similar to those observed in source tributaries suggests that contamination from at least two sources has been transported along the length of the river system. (5) Global fallout, a result of high-yield atmospheric weapons tests conducted by the FSU and USA primarily, is the dominant source of Pu and Np to the region; however, there have been brief periods when inputs from non-fallout sources exceeded those from global fallout.

  13. Hydrogen isotopic substitution of solid methylamine through atomic surface reactions at low temperatures: A potential contribution to the D/H ratio of methylamine in molecular clouds

    NASA Astrophysics Data System (ADS)

    Oba, Yasuhiro; Chigai, Takeshi; Osamura, Yoshihiro; Watanabe, Naoki; Kouchi, Akira

    2014-01-01

    We experimentally studied hydrogen (H)-deuterium (D) substitution reactions of solid methylamine (CH3NH2) under astrophysically relevant conditions. We also calculated the potential energy surface for the H-D substitution reactions of methylamine isotopologues using quantum chemical methods. Despite the relatively large energy barrier of more than 18 kJ mol-1, CH3NH2 reacted with D atoms to yield deuterated methylamines at 10 K, suggesting that the H-D substitution reaction proceeds through quantum tunneling. Deuterated methylamines reacted with H atoms as well. On the basis of present results, we propose that methylamine has potential for D enrichment through atomic surface reactions on interstellar grains at very low temperatures in molecular clouds. D enrichment would occur in particular in the methyl group of methylamine.

  14. Spatially-Resolved Analyses of Aerodynamic Fallout from a Uranium-Fueled Nuclear Test

    DOE PAGES

    Lewis, L. A.; Knight, K. B.; Matzel, J. E.; ...

    2015-07-28

    The fiive silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Several samples display compositional heterogeneity suggestive of incomplete mixing between major elements and natural U (238U/235U = 0.00725) and enriched U. Samples exhibit extreme spatial heterogeneity in U isotopic composition with 0.02 < 235U/238U < 11.84 among all five spherules and 0.02 < 235U/238U < 7.41 within a single spherule. Moreover, in two spherules, the 235U/238U ratio is correlated with changes in major element composition, suggesting the agglomeration ofmore » chemically and isotopically distinct molten precursors. Two samples are nearly homogenous with respect to major element and uranium isotopic composition, suggesting extensive mixing possibly due to experiencing higher temperatures or residing longer in the fireball. Linear correlations between 234U/238U, 235U/238U, and 236U/238U ratios are consistent with a two-component mixing model, which is used to illustrate the extent of mixing between natural and enriched U end members.« less

  15. Spatially-Resolved Analyses of Aerodynamic Fallout from a Uranium-Fueled Nuclear Test

    SciTech Connect

    Lewis, L. A.; Knight, K. B.; Matzel, J. E.; Prussin, S. G.; Zimmer, M. M.; Kinman, W S; Ryerson, F. J.; Hutcheon, I. D.

    2015-07-28

    The fiive silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Several samples display compositional heterogeneity suggestive of incomplete mixing between major elements and natural U (238U/235U = 0.00725) and enriched U. Samples exhibit extreme spatial heterogeneity in U isotopic composition with 0.02 < 235U/238U < 11.84 among all five spherules and 0.02 < 235U/238U < 7.41 within a single spherule. Moreover, in two spherules, the 235U/238U ratio is correlated with changes in major element composition, suggesting the agglomeration of chemically and isotopically distinct molten precursors. Two samples are nearly homogenous with respect to major element and uranium isotopic composition, suggesting extensive mixing possibly due to experiencing higher temperatures or residing longer in the fireball. Linear correlations between 234U/238U, 235U/238U, and 236U/238U ratios are consistent with a two-component mixing model, which is used to illustrate the extent of mixing between natural and enriched U end members.

  16. Spatially-resolved analyses of aerodynamic fallout from a uranium-fueled nuclear test.

    PubMed

    Lewis, L A; Knight, K B; Matzel, J E; Prussin, S G; Zimmer, M M; Kinman, W S; Ryerson, F J; Hutcheon, I D

    2015-10-01

    Five silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Several samples display compositional heterogeneity suggestive of incomplete mixing between major elements and natural U ((238)U/(235)U = 0.00725) and enriched U. Samples exhibit extreme spatial heterogeneity in U isotopic composition with 0.02 < (235)U/(238)U < 11.84 among all five spherules and 0.02 < (235)U/(238)U < 7.41 within a single spherule. In two spherules, the (235)U/(238)U ratio is correlated with changes in major element composition, suggesting the agglomeration of chemically and isotopically distinct molten precursors. Two samples are nearly homogenous with respect to major element and uranium isotopic composition, suggesting extensive mixing possibly due to experiencing higher temperatures or residing longer in the fireball. Linear correlations between (234)U/(238)U, (235)U/(238)U, and (236)U/(238)U ratios are consistent with a two-component mixing model, which is used to illustrate the extent of mixing between natural and enriched U end members.

  17. Fallout risk following a major nuclear attack on the United States.

    PubMed

    Harvey, T F; Shapiro, C S; Wittler, R F

    1992-01-01

    Fallout distributions are calculated for nuclear attacks on the contiguous United States. Four attack scenarios are treated, including counterforce and counterforce-countervalue attacks, for meteorological conditions associated with a typical day in summer and one in winter. The countervalue attacks contain mostly airbursts. To determine fallout effects, the population surviving the prompt effects is first calculated. For the prompt effects, a "conflagration-type" model is used. The counterforce attack produces about 8 million prompt deaths, and the counterforce-countervalue case projects 98 million prompt deaths. Partial relocation before attack to low-risk fallout areas at least 15 km from potential strategic targets would result in a decrease in projections of deaths by tens of millions. For fallout risk calculations, only the dose received in the first 48 h (the early or local fallout) is considered. Populations are assumed to be sheltered, with a shelter protection factor profile that varies for a large urban area, a small urban area, or a rural area. With these profiles, without relocation, the fallout fatalities for all four attack scenarios are calculated to be less than one million people. This can be compared to fallout fatalities of about 10 million for a hypothetical unsheltered "phantom" population.

  18. Fallout risk following a major nuclear attack on the United States

    SciTech Connect

    Harvey, T.F.; Shapiro, C.S.; Wittler, R.F. )

    1992-01-01

    Fallout distributions are calculated for nuclear attacks on the contiguous United States. Four attack scenarios are treated, including counterforce and counterforce-countervalue attacks, for meteorological conditions associated with a typical day in summer and one in winter. The countervalue attacks contain mostly airbursts. To determine fallout effects, the population surviving the prompt effects is first calculated. For the prompt effects, a 'conflagration-type' model is used. The counterforce attack produces about 8 million prompt deaths, and the counterforce-countervalue case projects 98 million prompt deaths. Partial relocation before attack to low-risk fallout areas at least 15 km from potential strategic targets would result in a decrease in projections of deaths by tens of millions. For fallout risk calculations, only the dose received in the first 48 h (the early or local fallout) is considered. Populations are assumed to be sheltered, with a shelter protection factor profile that varies for a large urban area, a small urban area, or a rural area. With these profiles, without relocation, the fallout fatalities for all four attack scenarios are calculated to be less than one million people. This can be compared to fallout fatalities of about 10 million for a hypothetical unsheltered 'phantom' population.

  19. Network-level fallout radiation-effects assessment. Final report

    SciTech Connect

    Not Available

    1989-05-12

    The EMP Mitigation Program analyzes, and where feasible, lessens the degradation effects of EMP on national telecommunication resources. The program focuses on the resources of the public switched network (PSN) because the PSN comprises the largest, most diverse set of telecommunication assets in the United States and is the focus of National Security Emergency Preparedness (NSEP) telecommunication enhancement activities. Additionally, the majority of various organizations rely on the PSN to conduct their NSEP telecommunications responsibilities. Telecommunication equipment is most susceptible to high altitude EMP (HEMP) which occurs when a nuclear weapon is detonated at an altitude greater that 50 km above the earth's surface. In addition to studying the effects of EMP, the program has expanded to address the effects of fallout radiation and serve traffic congestion on the PSN.

  20. Reduction of Fallout Radiation Hazards in Health Installations

    PubMed Central

    Waters, W. R.

    1962-01-01

    The purpose of this paper is to provide guidance for Canadian hospital medical directors in planning the provision of protection for their patients and staff against gamma radiation hazard from nuclear war. The implications of the distribution of fallout in Canada are that the probability of exposures in excess of 600 r in the period “96 hours after fallout” is high in Southern Ontario and Quebec but low in the western provinces and in the North. All hospitals should have a shielding capacity; for many, this will entail structural alterations. The aim would be to provide a protective factor of 100 or better, together with necessary standards of habitability. The engineering significance of the recommendations is discussed. PMID:13999154

  1. Another look at the calculation of fallout tephra volumes

    USGS Publications Warehouse

    Fierstein, J.; Nathenson, M.

    1992-01-01

    The calculation of volumes of fallout tephra layers is difficult because of the nonlinear dependence of thickness on area and because of the extrapolations required at the vent and in distal regions. Calculation using the trapezoidal rule, straight lines on log-log plots of area versus thickness, straight lines on plots of log thickness versus area1/2, and the crystal-concentration method are reviewed and the problems with each method discussed. The method using straight lines on plots of log thickness versus area1/2 is the most geologically reasonable because most deposits thin exponentially from source and therefore plot as straight lines using these coordinates. Errors and uncertainties in previous derivations for using this method are discussed and more general formulas presented. The method is also used to gain perspective on the "missing" distal volumes calculated by the crystal-concentration method compared to those calculated based only on isopach data. ?? 1992 Springer-Verlag.

  2. The surgical management of benign and malignant thyroid neoplasms in Marshall Islanders exposed to hydrogen bomb fallout.

    PubMed

    Dobyns, B M; Hyrmer, B A

    1992-01-01

    On March 1, 1954, a serious fallout accident occurred during the United States atomic testing program at Bikini in the Trust Territory of the Pacific Islands. Following the detonation of a large thermonuclear device (known as Bravo) an unexpected shift in winds resulted in deposition of radioactive debris on several inhabited atolls in the Marshall Islands. During the early post-detonation period military, sea, and air surveys traced the hottest portion of the parabolic cloud as it drifted in an ever widening pattern of diminishing concentration eastward and southeast of Bikini. The center of the cloud passed North of the Rongelap Atoll, which was the nearest inhabited atoll. This report concerns the development of thyroid lesions, the special circumstances encountered during thyroid surgery, and the results of the surgical management of benign and malignant lesions that were subsequently encountered in this population.

  3. Fallout from Chernobyl and incidence of childhood leukaemia in Finland, 1976-92.

    PubMed Central

    Auvinen, A.; Hakama, M.; Arvela, H.; Hakulinen, T.; Rahola, T.; Suomela, M.; Söderman, B.; Rytömaa, T.

    1994-01-01

    OBJECTIVE--To assess effects of fallout from Chernobyl on incidence of childhood leukaemia in Finland. DESIGN--Nationwide cohort study. External exposure measured for 455 Finnish municipalities with instruments driven 19,000 km throughout the country. Values specific to municipalities corrected for shielding due to houses and fallout from A bomb testing. Internal exposure estimated from whole body measurements on a random sample of 81 children. Mean effective dose for two years after incident calculated from these measurements. Data on childhood leukaemia obtained from Finnish cancer registry and verified through hospitals treating childhood cancers. SETTING--Finland, one of the countries most heavily contaminated by the Chernobyl accident; the population was divided into fifths by exposure. SUBJECTS--Children aged 0-14 years in 1976-92. MAIN OUTCOME MEASURES--Standardised incidence ratio of childhood leukaemia and relative excess risk of childhood leukaemia per mSv. From incidence data of Finnish cancer registry for 1976-85, expected numbers specific to sex and age group (0-4, 5-9, and 10-14 years) were calculated for each municipality for three periods (1976-85, 1986-8, and 1989-92) and pooled as exposure fifths. Dose response was estimated as regression slope of standardised incidence ratios on mean doses for fifths for each period. RESULTS--Population weighted mean effective doses for first two years after the accident were 410 microSv for the whole country and 970 microSv for the population fifth with the highest dose. In all Finland the incidence of childhood leukaemia did not increase 1976-92. The relative excess risk 1989-92 was not significantly different from zero (7% per mSv; 95% confidence interval -27% to 41%). CONCLUSIONS--An important increase in childhood leukaemia can be excluded. Any effect is smaller than eight extra cases per million children per year in Finland. The results are consistent with the magnitude of effect expected. PMID:8044092

  4. Transfer of sup 137 Cs to milk and meat in Hungary from Chernobyl fallout with comparisons of worldwide fallout in the 1960s

    SciTech Connect

    Ward, G.M.; Keszthelyi, Z.; Kanyar, B.; Kralovanszky, U.P.; Johnson, J.E. )

    1989-10-01

    Transfer coefficients for 137Cs from the Chernobyl accident were determined for milk (Fm) and meat (Ff) of cows and sheep in Hungary. Fm and Ff for both cows and sheep fed forage harvested within 1 mo of the accident were lower than results reported for worldwide fallout from weapons tests. Forage harvested 60 d or later after the accident produced an Fm similar to results from feeding soluble 134Cs. The results are interpreted to indicate three distinct categories of Fm about 2.0 X 10(-3), 4.0 X 10(-3) and 1.4 X 10(-2) d L-1, respectively, for Chernobyl fallout, worldwide fallout and soluble Cs isotopes or 137Cs contained in plants from soil uptake.

  5. Determination of Volatility and Element Fractionation in Glassy Fallout Debris by SIMS

    SciTech Connect

    Williamson, Todd L.; Tenner, Travis Jay; Bonamici, Chloe Elizabeth; Kinman, William Scott; Pollington, Anthony Douglas; Steiner, Robert Ernest

    2016-05-10

    The purpose of this report is to characterize glassy fallout debris using the Trinity Test and then characterize the U-isotopes of U3O8 reference materials that contain weaponized debris.

  6. Redistribution of fallout radionuclides in Enewetak Atoll lagoon sediments by callianassid bioturbation.

    PubMed

    McMurtry, G M; Schneider, R C; Colin, P L; Buddemeier, R W; Suchanek, T H

    The lagoon sediments of Enewetak Atoll in the Marshall Islands contain a large selection of fallout radionuclides as a result of 43 nuclear weapon tests conducted there between 1948 and 1958. Studies of the burial of fallout radionuclides have been conducted on the islands and in several of the large craters, but studies of their vertical distribution have been limited to about the upper 20 cm of the lagoon sediments. We have found elevated fallout radionuclide concentrations buried more deeply in the lagoon sediments and evidence of burrowing into the sediment by several species of callianassid ghost shrimp (Crustacea: Thalassinidea) which has displaced highly radioactive sediment. The burrowing activities of callianassids, which are ubiquitous on the lagoon floor, facilitate radionuclide redistribution and complicate the fallout radionuclide inventory of the lagoon.

  7. Standard KDF0C4 Fallout Calculations for Buried Nuclear Detonations

    SciTech Connect

    Serduke, F J D

    2001-09-14

    The collateral damage caused by fallout from shallow-buried nuclear devices is of considerable interest. In this paper, we present results for ''standard'' calculations using the KDFOC4 fallout computer code. Results are presented for a parametric range of yields from 0.1 kt to 1 Mt in equally-spaced logarithmic increments and for emplacement depths of 5 meters in hard, dry rock and 20 meters in moist soil. We will see that for low yields, this emplacement depth has a marked influence on the shape of the fallout patterns but for the highest yields, the fallout patterns are insensitive to the emplacement medium and depth. We look at two categories of doses: (1) Those for which health effects begin to be serious and range upward to lethal, and (2) Doses that are politically very sensitive but for which any deleterious health effects are difficult to prove.

  8. Plutonium segregation in glassy aerodynamic fallout from a nuclear weapon test.

    PubMed

    Holliday, K S; Dierken, J M; Monroe, M L; Fitzgerald, M A; Marks, N E; Gostic, R C; Knight, K B; Czerwinski, K R; Hutcheon, I D; McClory, J W

    2017-02-14

    This study combines electron microscopy equipped with energy dispersive spectroscopy to probe major element composition and autoradiography to map plutonium in order to examine the spatial relationships between plutonium and fallout composition in aerodynamic glassy fallout from a nuclear weapon test. A sample set of 48 individual fallout specimens were interrogated to reveal that the significant chemical heterogeneity of this sample set could be described compositionally with a relatively small number of compositional endmembers. Furthermore, high concentrations of plutonium were never associated with several endmember compositions and concentrated with the so-called mafic glass endmember. This result suggests that it is the physical characteristics of the compositional endmembers and not the chemical characteristics of the individual component elements that govern the un-burnt plutonium distribution with respect to major element composition in fallout.

  9. Precise determination of the absolute isotopic abundance ratio and the atomic weight of chlorine in three international reference materials by the positive thermal ionization mass spectrometer-Cs2Cl+-graphite method.

    PubMed

    Wei, Hai-Zhen; Jiang, Shao-Yong; Xiao, Ying-Kai; Wang, Jun; Lu, Hai; Wu, Bin; Wu, He-Pin; Li, Qing; Luo, Chong-Guang

    2012-12-04

    Because the variation in chlorine isotopic abundances of naturally occurring chlorine bearing substances is significant, the IUPAC Inorganic Chemistry Division, Commission on Isotopic Abundances and Atomic Weights (CIAAW-IUPAC) decided that the uncertainty of atomic weight of chlorine (A(r)(Cl)) should be increased so that the implied range was related to terrestrial variability in 1999 (Coplen, T. B. Atomic weights of the elements 1999 (IUPAC Technical Report), Pure Appl. Chem.2001, 73(4), 667-683; and then, it emphasized that the standard atomic weights of ten elements including chlorine were not constants of nature but depend upon the physical, chemical, and nuclear history of the materials in 2009 (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396). According to the agreement by CIAAW that an atomic weight could be defined for one specified sample of terrestrial origin (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396), the absolute isotope ratios and atomic weight of chlorine in standard reference materials (NIST 975, NIST 975a, ISL 354) were accurately determined using the high-precision positive thermal ionization mass spectrometer (PTIMS)-Cs(2)Cl(+)-graphite method. After eliminating the weighing error caused from evaporation by designing a special weighing container and accurately determining the chlorine contents in two highly enriched Na(37)Cl and Na(35)Cl salts by the current constant coulometric titration, one series of gravimetric synthetic mixtures prepared from two highly enriched Na(37)Cl and Na(35)Cl salts was used to calibrate two thermal ionization mass spectrometers in two individual laboratories. The correction factors (i.e., K(37/35) = R(37/35meas)/R(37/35calc)) were obtained from five cycles of iterative calculations on the basis of calculated and determined R((37)Cl/(35)Cl) values in gravimetric synthetic mixtures. The absolute R((37)Cl/(35)Cl) ratios for NIST SRM 975, NIST 975a, and ISL 354 by the precise

  10. SIMS Analyses of Aerodynamic Fallout from a Uranium-Fueled Test

    SciTech Connect

    Lewis, L. A.; Knight, K. B.; Matzel, J. E.; Prussin, S. G.; Ryerson, F. J.; Kinman, W. S.; Zimmer, M. M.; Hutcheon, I. D.

    2014-09-09

    Five silicate fallout glass spherules produced in a uranium-fueled, near-surface nuclear test were characterized by secondary ion mass spectrometry, electron probe microanalysis, autoradiography, scanning electron microscopy, and energy-dispersive x ray spectroscopy. Several samples display distinctive compositional heterogeneity suggestive of incomplete mixing, and exhibit heterogeneity in U isotopes with 0.02 < 235U/ 238U < 11.8 among all five samples and 0.02 < 235U/ 238U < 7.81 within a single sample. In two samples, the 235U/ 238U ratio is correlated with major element composition, consistent with the agglomeration of chemically and isotopically distinct molten precursors. Two samples are quasi-homogeneous with respect to composition and uranium isotopic composition, suggesting extensive mixing possibly due longer residence time in the fireball. Correlated variations between 234U, 235U, 236U and 238U abundances point to mixing of end-members corresponding to uranium derived from the device and natural U ( 238U/ 235U = 0.00725) found in soil.

  11. Tephra fallout hazards at Quito International Airport (Ecuador)

    NASA Astrophysics Data System (ADS)

    Volentik, Alain C. M.; Houghton, Bruce F.

    2015-06-01

    Tephra fallout is the most widespread hazard posed by explosive volcanic eruptions. The 2010 explosive eruption of Eyjafjallajökull in Iceland significantly exposed the vulnerability of aviation operations to volcanic ash. The presence of fine ash in the atmosphere forced authorities to close most of European airspace for almost a week. A worldwide study of airport operations disrupted by volcanic eruptions (Guffanti et al., Nat Hazards 51:287-302, 2009) showed significant past exposure to tephra fall of the old international airport (OUIO) in Quito, Ecuador. A new international airport, Mariscal Sucre International Airport (UIO), located 15 km due east to OUIO, started operations on February 20, 2013. Given its location close to the old airport, UIO is also at risk for tephra fallout in the future. We identified five volcanoes capable of producing tephra hazard at UIO. Three (Guagua Pichincha, Reventador, and Tungurahua) are currently active and have recently disrupted aviation operations in Ecuador. The other two (Cotopaxi and Pululagua) are not currently active, but any future eruption from these two volcanoes would probably be explosive, hence capable of producing tephra hazard to UIO. As eruption parameters and wind profiles cannot be forecast in advance, we used a probabilistic approach to quantify the probability of tephra accumulation exceeding 1 mm and 1 cm (regarded as non-conservative and conservative bounds for airport disruption) following an explosive eruption from each volcano. Each eruptive parameter was randomly sampled within a predefined distribution, and wind profiles are randomly sampled within a 5-year dataset. The probability of tephra accumulation reaching 1 mm and 1 cm at UIO is 14.3-19.9 and 2.5-5.8 %, respectively, for Cotopaxi; 17.5-19.9 and 7-7.7 %, respectively, for Guagua Pichincha; and 44.3-44.8 and 18.8-24.9 %, respectively, for Pululagua. According to our results, Reventador and Tungurahua are not likely to yield tephra

  12. Alimentary Tract Absorption (f1 Values) for Radionuclides in Local and Regional Fallout from Nuclear Tests

    PubMed Central

    Ibrahim, Shawki; Simon, Steven L; Bouville, André; Melo, Dunstana; Beck, Harold

    2009-01-01

    This paper presents gastrointestinal absorption fractions (f1 values) for estimating internal doses from local and regional fallout radionuclides due to nuclear tests. The choice of f1 values are based on specific circumstances of weapons test conditions and a review of reported f1 values for elements in different physical and chemical states. Special attention is given to fallout from nuclear tests conducted at the Marshall Islands. We make a distinction between the f1 values for intakes of radioactive materials immediately after deposition (acute intakes) and intakes that occur in the course of months and years after deposition, following incorporation into terrestrial and aquatic foodstuffs (chronic intakes). Multiple f1 values for different circumstances where persons are exposed to radioactive fallout (e.g. local vs. regional fallout and coral vs. continental tests) are presented when supportive information is available. In some cases, our selected f1 values are similar to those adopted by the ICRP (e.g. iodine and most actinides). However, f1 values for cesium and strontium derived from urine bioassay data of the Marshallese population are notably lower than the generic f1 values recommended by ICRP, particularly for acute intakes from local fallout (0.4 and 0.05 for Cs and Sr, respectively. The f1 values presented here form the first complete set of values relevant to realistic dose assessments for exposure to local or regional radioactive fallout. PMID:20622554

  13. When the dust settles: stable xenon isotope constraints on the formation of nuclear fallout.

    PubMed

    Cassata, W S; Prussin, S G; Knight, K B; Hutcheon, I D; Isselhardt, B H; Renne, P R

    2014-11-01

    Nuclear weapons represent one of the most immediate threats of mass destruction. In the event that a procured or developed nuclear weapon is detonated in a populated metropolitan area, timely and accurate nuclear forensic analysis and fallout modeling would be needed to support attribution efforts and hazard assessments. Here we demonstrate that fissiogenic xenon isotopes retained in radioactive fallout generated by a nuclear explosion provide unique constraints on (1) the timescale of fallout formation, (2) chemical fractionation that occurs when fission products and nuclear fuel are incorporated into fallout, and (3) the speciation of fission products in the fireball. Our data suggest that, in near surface nuclear tests, the presence of a significant quantity of metal in a device assembly, combined with a short time allowed for mixing with the ambient atmosphere (seconds), may prevent complete oxidation of fission products prior to their incorporation into fallout. Xenon isotopes thus provide a window into the chemical composition of the fireball in the seconds that follow a nuclear explosion, thereby improving our understanding of the physical and thermo-chemical conditions under which fallout forms.

  14. A comparison of airborne bacterial fallout between orthopaedic and vascular surgery.

    PubMed

    Stather, P; Salji, M; Hassan, S-U; Abbas, M; Ahmed, A; Mills, H; Elston, T; Backhouse, C; Howard, A; Choksy, S

    2017-04-01

    INTRODUCTION The objective of the study was to compare bacterial fallout during vascular prosthesis insertion and orthopaedic major joint replacement performed in conventional and laminar flow ventilation, respectively. MATERIALS AND METHODS A prospective single-centre case control study of 21 consecutive elective vascular procedures involving prosthetic graft insertion and 24 consecutive elective orthopaedic major joint replacements were tested for degree of bacterial fallout using agar settle plates. Preparation time, waiting time and total procedure duration were collected at the time of surgery, and bacterial colony counts on the agar settle plates from airborne bacterial fallout were counted after an incubation period. RESULTS Bacterial fallout count in vascular prosthetic graft insertion was 15-fold greater than in orthopaedic prosthetic joint insertion (15, (IQR 15) vs 1, (IQR 3) respectively, P < 0.0001, Wilcoxon). Waiting time and patient transfer did not significantly increase bacterial fallout counts during the procedure (P = 0.9). CONCLUSIONS Vascular surgical theatres have significantly higher bacterial fallout compared with orthopaedic theatres. This may be partly explained by orthopaedic surgery being routinely performed in laminar flow ventilation, a practice which has not been widely adopted for vascular surgery, in which prosthetic infection may also result in significant mortality and morbidity.

  15. Alimentary tract absorption (f1 values) for radionuclides in local and regional fallout from nuclear tests.

    PubMed

    Ibrahim, Shawki A; Simon, Steven L; Bouville, André; Melo, Dunstana; Beck, Harold L

    2010-08-01

    This paper presents gastrointestinal absorption fractions (f1 values) for estimating internal doses from local and regional fallout radionuclides due to nuclear tests. The choice of f1 values are based on specific circumstances of weapons test conditions and a review of reported f1 values for elements in different physical and chemical states. Special attention is given to fallout from nuclear tests conducted at the Marshall Islands. We make a distinction between the f1 values for intakes of radioactive materials immediately after deposition (acute intakes) and intakes that occur in the course of months and years after deposition, following incorporation into terrestrial and aquatic foodstuffs (chronic intakes). Multiple f1 values for different circumstances where persons are exposed to radioactive fallout (e.g., local vs. regional fallout and coral vs. continental tests) are presented when supportive information is available. In some cases, our selected f1 values are similar to those adopted by the International Commission on Radiological Protection (ICRP) (e.g., iodine and most actinides). However, f1 values for cesium and strontium derived from urine bioassay data of the Marshallese population are notably lower than the generic f1 values recommended by ICRP, particularly for acute intakes from local fallout (0.4 and 0.05 for Cs and Sr, respectively). The f1 values presented here form the first complete set of values relevant to realistic dose assessments for exposure to local or regional radioactive fallout.

  16. Improving Signal-to-Noise Ratio in Scanning Transmission Electron Microscopy Energy-Dispersive X-Ray (STEM-EDX) Spectrum Images Using Single-Atomic-Column Cross-Correlation Averaging.

    PubMed

    Jeong, Jong Seok; Mkhoyan, K Andre

    2016-06-01

    Acquiring an atomic-resolution compositional map of crystalline specimens has become routine practice, thus opening possibilities for extracting subatomic information from such maps. A key challenge for achieving subatomic precision is the improvement of signal-to-noise ratio (SNR) of compositional maps. Here, we report a simple and reliable solution for achieving high-SNR energy-dispersive X-ray (EDX) spectroscopy spectrum images for individual atomic columns. The method is based on standard cross-correlation aided by averaging of single-column EDX maps with modifications in the reference image. It produces EDX maps with minimal specimen drift, beam drift, and scan distortions. Step-by-step procedures to determine a self-consistent reference map with a discussion on the reliability, stability, and limitations of the method are presented here.

  17. Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes

    PubMed Central

    Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

    2016-01-01

    Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for. PMID:27067389

  18. Early detection of radioactive fallout by gamma spectrometry.

    PubMed

    Aage, H K; Korsbech, U; Bargholz, K

    2003-01-01

    Radioactive fallout should be detected as early as possible. A new and efficient method for detection of low-level irradiation from manmade radioactivity is developed. Radiation abnormalities are detectable down to air kerma rates of 0.5 to 1.0 nGy h(-1) for 137Cs and even lower for 131I. For multi-gamma energy radioactivity the detection level is 2.6-3.5 nGy h(-1). A standard NaI detector and a 512-channel analyser are used together with noise adjusted singular value decomposition (NASVD). Statistical noise is removed and the measured spectra are reproduced using spectral components produced by NASVD. Stripping is not used and false alarms due to washout of atmospheric radon progeny are almost eliminated. Detection levels and the criteria for setting warning and alarm levels are discussed. The method may also be useful in other situations, for example where low-level signals from radioactive sources need to be detected.

  19. Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes.

    PubMed

    Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

    2016-04-12

    Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for.

  20. Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes

    NASA Astrophysics Data System (ADS)

    Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

    2016-04-01

    Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for.

  1. Dispersal and fallout simulations for urban consequences management (u)

    SciTech Connect

    Grinstein, Fernando F; Wachtor, Adam J; Nelson, Matt; Brown, Michael; Bos, Randy; Patnik, Gopal

    2010-01-01

    Hazardous chemical, biological, or radioactive releases from leaks, spills, fires, or blasts, may occur (intentionally or accidentally) in urban environments during warfare or as part of terrorist attacks on military bases or other facilities. The associated contaminant dispersion is complex and semi-chaotic. Urban predictive simulation capabilities can have direct impact in many threat-reduction areas of interest, including, urban sensor placement and threat analysis, contaminant transport (CT) effects on surrounding civilian population (dosages, evacuation, shelter-in-place), education and training of rescue teams and services. Detailed simulations for the various processes involved are in principle possible, but generally not fast. Predicting urban airflow accompanied by CT presents extremely challenging requirements. Crucial technical issues include, simulating turbulent fluid and particulate transport, initial and boundary condition modeling incorporating a consistent stratified urban boundary layer with realistic wind fluctuations, and post-processing of the simulation results for practical consequences management. Relevant fluid dynamic processes to be simulated include, detailed energetic and contaminant sources, complex building vortex shedding and flows in recirculation zones, and modeling of particle distributions, including particulate fallout, as well as deposition, re-suspension and evaporation. Other issues include, modeling building damage effects due to eventual blasts, addressing appropriate regional and atmospheric data reduction.

  2. Internally deposited fallout from the Chernobyl reactor accident

    SciTech Connect

    Schlenker, R.A.; Oltman, B.G.; Lucas, H.F.

    1987-01-01

    Measurements of fallout radioactivity were made in the thyroid region, abdomen, whole body, or urine of 96 persons who were in eastern Europe at the time of the Chernobyl reactor accident or who went there shortly afterward. The most frequently encountered radionuclides were /sup 131/I, /sup 134,137/Cs, and /sup 103/Ru//sup 103/Rh. The median /sup 131/I activity in the thyroids of 42 subjects in whom radioiodine was detected and who were in Europe when the accident began was projected as 42 nCi the day the accident began. The median total body activity of /sup 134/Cs in 40 subjects in which it was detected was 1.7 nCi upon arrival in the US. For 51 subjects with detectable /sup 137/Cs burdens, the total body activity was 4.6 nCi. The risk of fatal thyroid cancer is less than 3 x 10/sup -6/ for nearly all subjects in this series. The risk of fatal cancer from /sup 134,137/Cs for subjects with cesium exposures similar to the ones observed by us, but who remained in Europe, is estimated as 1.4 x 10/sup -6/ to 4.2 x 10/sup -5/ with 95% of the risk attributable to /sup 137/Cs. 5 refs., 4 tabs.

  3. Fallout plutonium in two oxic-anoxic environments

    SciTech Connect

    Sanchez, A.L.; Murray, J.W.; Schell, W.R.; Miller, L.G.

    1986-09-01

    The profiles of soluble fallout plutonium in two partially anoxic waters revealed minimum concentrations at the O/sub 2/-H/sub 2/S interface, indicating Pu removal onto particulate phases of Fe and other oxidized species that form during the redox cycle. In Saanich Inlet, an intermittently anoxic fjord in Vancouver Island, Canada, the concentration of soluble Pu in the anoxic zone was slightly less than in the oxygenated surface layer. In Soap Lake, a saline meromictic lake in eastern Washington State, Pu concentrations i the permanently anoxic zone were at least an order of magnitude higher than at the surface. Differences in the chemical characteristics of these two waters suggest important chemical species that influenced the observed Pu distribution. In the permanently anoxic zone of Soap Lake, high values of total alkalinity ranging from 940 to 1500 meq liter/sup -1/, sulfide species from 38 to 128 ..mu..M, dissolved organic carbon from 163 to 237 mg liter/sup -1/, and total dissolved solids from 80 to 140 ppt, all correlated with the observed high concentration of Pu. In Saanich Inlet, where total alkalinity ranged from 2.1 to 2.4 meq liter/sup -1/ and salinity from 25 to 32 per thousand and H/sub 2/S concentration in May 1981 showed a maximum of 8..mu..M, the observed Pu concentrations were significantly lower than for the Soap Lake monimolimnion.

  4. Global risk of radioactive fallout after nuclear reactor accidents

    NASA Astrophysics Data System (ADS)

    Kunkel, D.; Lelieveld, J.; Lawrence, M. G.

    2012-04-01

    Reactor core meltdowns of nuclear power plants are rare, yet the consequences are catastrophic. But what is meant by "rare"? And what can be learned from the Chernobyl and Fukushima incidents? Here we assess the risk of exposure to radioactivity due to atmospheric dispersion of gases and particles following severe nuclear accidents, using particulate 137Cs and gaseous 131I as proxies for the fallout. It appears that previously the occurrence of major accidents and the risks of radioactive contamination have been underestimated. Using a global model of the atmosphere we compute that on average, in the event of a core melt of any nuclear power plant worldwide, more than 90 % of emitted 137Cs would be transported beyond 50 km and about 50 % beyond 1000 km distance. This corroborates that such accidents have large-scale and trans-boundary impacts. Although the emission strengths and atmospheric removal processes of 137Cs and 131I are quite different, the radioactive contamination patterns over land and the human deposition exposure are computed to be similar. High human exposure risks occur around reactors in densely populated regions, notably in southern Asia where a core melt can subject 55 million people to radioactive contamination. The recent decision by Germany to phase out its nuclear reactors will reduce the national risk, though a large risk will still remain from the reactors in neighbouring countries.

  5. Global risk of radioactive fallout after nuclear reactor accidents

    NASA Astrophysics Data System (ADS)

    Lelieveld, J.; Kunkel, D.; Lawrence, M. G.

    2011-11-01

    Reactor core meltdowns of nuclear power plants are rare, yet the consequences are catastrophic. But what is meant by "rare"? And what can be learned from the Chernobyl and Fukushima incidents? Here we assess the risk of exposure to radioactivity due to atmospheric dispersion of gases and particles following severe nuclear accidents, using particulate 137Cs and gaseous 131I as proxies for the fallout. It appears that previously the occurrence of major accidents and the risks of radioactive contamination have been underestimated. Using a global model of the atmosphere we compute that on average, in the event of a core melt of any nuclear power plant worldwide, more than 90% of emitted 137Cs would be transported beyond 50km and about 50% beyond 1000 km distance. This corroborates that such accidents have large-scale and trans-boundary impacts. Although the emission strengths and atmospheric removal processes of 137Cs and 131I are quite different, the radioactive contamination patterns over land and the human deposition exposure are computed to be similar. High human exposure risks occur around reactors in densely populated regions, notably in southern Asia where a core melt can subject 55 million people to radioactive contamination. The recent decision by Germany to phase out its nuclear reactors will reduce the national risk, though a large risk will still remain from the reactors in neighbouring countries.

  6. Determination of the 240Pu/ 239Pu atomic ratio in soils from Palomares (Spain) by low-energy accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Chamizo, E.; García-León, M.; Synal, H.-A.; Suter, M.; Wacker, L.

    2006-08-01

    In 1966, the nuclear fuel of two thermonuclear bombs was released over the Spanish region of Palomares, due to a B52 bomber accident during a refuelling operation. Since then, much effort has been made to assess its impact to the different environmental compartments of this area in South-East Spain, mostly by measuring the 239+240Pu activity concentration and the 238Pu/239+240Pu activity ratio. Nevertheless, these measurements do not give enough information on the problem. In order to recognize unambiguously small traces of the weapon-grade plutonium released in the accident, the ratio of the two major isotopes of plutonium, 240Pu/239Pu, has to be determined. In this work, this ratio has been measured in low- and high-activity samples from Palomares by means of low-energy accelerator mass spectrometry (AMS). That way, we will show the potential of the new generation of compact AMS facilities in terms of plutonium characterization at ultra-trace levels.

  7. The isotopic record of atmospheric lead fall-out on an Icelandic salt marsh since AD 50.

    PubMed

    Marshall, William A; Clough, Robert; Gehrels, W Roland

    2009-04-01

    We report a record of atmospheric Pb deposition at a coastal site in western Iceland that spans the last two millennia. The elemental concentrations of Pb, Al, Li and Ti are determined using ICP-MS from a sediment monolith collected from a salt marsh. Multicollector (MC) ICP-MS analysis is used to obtain isotopic ratios of stable Pb. The Pb/Ti and Pb/Li ratios are used to separate natural Pb background concentrations from Pb derived from remote anthropogenic sources. The pollution record in western Iceland is subdued in comparison with Pb records from the European mainland, but the isotopic character, profile and timing of Pb deposition show good agreement with the atmospheric Pb fall-out reported from sites in Scandinavia and northwestern Europe. At the bottom of the sequence we isolate a low-level (0.1-0.4 mg kg(-1)) Pb enrichment signal dated to AD 50-150. The isotopic signature and timing of this signal suggest Roman metal working industries as the source. In the subsequent millennium there was no significant or very low (i.e. elemental concentrations<0.01 mg kg(-1)) anthropogenic Pb deposition at the site up to, and including, the early Medieval period. Above a pumice layer, dated to AD 1226-1227, a small increase in Pb deposition is found. This trend is maintained until a more substantive and progressive increase is signalled during the late 1700s and early 1800s. This is followed by a substantial enrichment signal in the sediments (>3.0 mg kg(-1)) that is interpreted as derived from industrial coal burning and metal working during the 19th and 20th centuries in northern Europe. During the late 20th century, significant fall-out from European fuel additives reached Iceland.

  8. Evidence of the radioactive fallout in France due to the Fukushima nuclear accident.

    PubMed

    Evrard, Olivier; Van Beek, Pieter; Gateuille, David; Pont, Véronique; Lefèvre, Irène; Lansard, Bruno; Bonté, Philippe

    2012-12-01

    Radioactive fallout due to the Fukushima reactor explosion in Japan was detected in environmental samples collected in France. The presence of (131)I in aerosols (200±6 μBq m(-3)) collected at the Pic du Midi observatory, located at 2877 m altitude in the French Pyrénées, indicated that the Japanese radioactive cloud reached France between 22 and 29 March, i.e. less than two weeks after the initial emissions, as suggested by a (137)Cs/(134)Cs ratio of 1.4. Cesium radioisotopes ((134)Cs and (137)Cs) were not detected in this sample but they were present in the aerosol sample collected the next week, i.e. between 29 March and 05 April (about 10 μBq m(-3)). We also report (131)I activities measured in grass (1.1-11 Bq kg(-1); fresh weight) and soil samples (0.4 Bq kg(-1)) collected in the Seine River basin between 30 March and 10 April. The (134)Cs from the damaged Fukushima power plant was also detected in grass collected in the Seine River basin between 31 March and 10 April (0.2-1.6 Bq kg(-1) fresh weight, with a (137)Cs/(134)Cs ratio close to 1, which is consistent with Fukushima radioactive release). Despite the installation of a network of nested stations to collect suspended matter in the upstream part of the Seine River basin, (131)I was only detected in suspended matter (4.5-60 Bq kg(-1)) collected at the most upstream stations between 30 March and 12 April. Neither (131)I nor (134)Cs has been detected in environmental samples since the end of April 2011, because of the rapid decay of (131)I and the very low activities of (134)Cs (about 400 times lower than after Chernobyl accident).

  9. Experimental investigation of inhomogeneities, nanoscopic phase separation, and magnetism in arc melted Fe-Cu metals with equal atomic ratio of the constituents

    NASA Astrophysics Data System (ADS)

    Hassnain Jaffari, G.; Aftab, M.; Anjum, D. H.; Cha, Dongkyu; Poirier, Gerald; Ismat Shah, S.

    2015-12-01

    Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a magnetic moment being equal to about 2.13 μB/ Fe atom and a bulk like negligible value of coercivity over the temperature range of 5-300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in magnetic character. However, for the annealed sample phase separated Fe exhibited homogenous strain.

  10. Fallout plume of submerged oil from Deepwater Horizon.

    PubMed

    Valentine, David L; Fisher, G Burch; Bagby, Sarah C; Nelson, Robert K; Reddy, Christopher M; Sylva, Sean P; Woo, Mary A

    2014-11-11

    The sinking of the Deepwater Horizon in the Gulf of Mexico led to uncontrolled emission of oil to the ocean, with an official government estimate of ∼ 5.0 million barrels released. Among the pressing uncertainties surrounding this event is the fate of ∼ 2 million barrels of submerged oil thought to have been trapped in deep-ocean intrusion layers at depths of ∼ 1,000-1,300 m. Here we use chemical distributions of hydrocarbons in >3,000 sediment samples from 534 locations to describe a footprint of oil deposited on the deep-ocean floor. Using a recalcitrant biomarker of crude oil, 17α(H),21β(H)-hopane (hopane), we have identified a 3,200-km(2) region around the Macondo Well contaminated by ∼ 1.8 ± 1.0 × 10(6) g of excess hopane. Based on spatial, chemical, oceanographic, and mass balance considerations, we calculate that this contamination represents 4-31% of the oil sequestered in the deep ocean. The pattern of contamination points to deep-ocean intrusion layers as the source and is most consistent with dual modes of deposition: a "bathtub ring" formed from an oil-rich layer of water impinging laterally upon the continental slope (at a depth of ∼ 900-1,300 m) and a higher-flux "fallout plume" where suspended oil particles sank to underlying sediment (at a depth of ∼ 1,300-1,700 m). We also suggest that a significant quantity of oil was deposited on the ocean floor outside this area but so far has evaded detection because of its heterogeneous spatial distribution.

  11. Fallout plume of submerged oil from Deepwater Horizon

    PubMed Central

    Valentine, David L.; Fisher, G. Burch; Bagby, Sarah C.; Nelson, Robert K.; Reddy, Christopher M.; Sylva, Sean P.; Woo, Mary A.

    2014-01-01

    The sinking of the Deepwater Horizon in the Gulf of Mexico led to uncontrolled emission of oil to the ocean, with an official government estimate of ∼5.0 million barrels released. Among the pressing uncertainties surrounding this event is the fate of ∼2 million barrels of submerged oil thought to have been trapped in deep-ocean intrusion layers at depths of ∼1,000–1,300 m. Here we use chemical distributions of hydrocarbons in >3,000 sediment samples from 534 locations to describe a footprint of oil deposited on the deep-ocean floor. Using a recalcitrant biomarker of crude oil, 17α(H),21β(H)-hopane (hopane), we have identified a 3,200-km2 region around the Macondo Well contaminated by ∼1.8 ± 1.0 × 106 g of excess hopane. Based on spatial, chemical, oceanographic, and mass balance considerations, we calculate that this contamination represents 4–31% of the oil sequestered in the deep ocean. The pattern of contamination points to deep-ocean intrusion layers as the source and is most consistent with dual modes of deposition: a “bathtub ring” formed from an oil-rich layer of water impinging laterally upon the continental slope (at a depth of ∼900–1,300 m) and a higher-flux “fallout plume” where suspended oil particles sank to underlying sediment (at a depth of ∼1,300–1,700 m). We also suggest that a significant quantity of oil was deposited on the ocean floor outside this area but so far has evaded detection because of its heterogeneous spatial distribution. PMID:25349409

  12. Global risk of radioactive fallout after major nuclear reactor accidents

    NASA Astrophysics Data System (ADS)

    Lelieveld, J.; Kunkel, D.; Lawrence, M. G.

    2012-05-01

    Major reactor accidents of nuclear power plants are rare, yet the consequences are catastrophic. But what is meant by "rare"? And what can be learned from the Chernobyl and Fukushima incidents? Here we assess the cumulative, global risk of exposure to radioactivity due to atmospheric dispersion of gases and particles following severe nuclear accidents (the most severe ones on the International Nuclear Event Scale, INES 7), using particulate 137Cs and gaseous 131I as proxies for the fallout. Our results indicate that previously the occurrence of INES 7 major accidents and the risks of radioactive contamination have been underestimated. Using a global model of the atmosphere we compute that on average, in the event of a major reactor accident of any nuclear power plant worldwide, more than 90% of emitted 137Cs would be transported beyond 50 km and about 50% beyond 1000 km distance before being deposited. This corroborates that such accidents have large-scale and trans-boundary impacts. Although the emission strengths and atmospheric removal processes of 137Cs and 131I are quite different, the radioactive contamination patterns over land and the human exposure due to deposition are computed to be similar. High human exposure risks occur around reactors in densely populated regions, notably in West Europe and South Asia, where a major reactor accident can subject around 30 million people to radioactive contamination. The recent decision by Germany to phase out its nuclear reactors will reduce the national risk, though a large risk will still remain from the reactors in neighbouring countries.

  13. Inversion is the Solution to Dispersion: Modeling Tephra Fallout

    NASA Astrophysics Data System (ADS)

    Connor, C.

    2005-12-01

    Volcanologists increasingly rely on numerical simulations to understand the dynamics of erupting volcanoes. Mathematical models are often used to explain the geologic processes responsible for eruption deposits found in the geologic record, and to better characterize possible hazards from future volcanic activity. We wish to estimate parameters related to the dynamics of volcanic activity directly from field observations. For example, how well can we estimate the magnitude of an eruption from measurements of tephra deposits? One solution lies in coupling our numerical simulations of volcanic eruption phenomena to inversion methods that search for an optimal set of parameters that explains our observations. Here we use observations of tephra thickness and granulometry from the 1992 eruption of Cerro Negro volcano, Nicaragua, to test the performance of a numerical simulation of tephra fallout. The downhill simplex inversion method is used to search for optimal parameters, including the eruption column height, eruption mass, and wind velocity as a function of elevation about the volcanic vent, that produce deposits that best fit the thickness and grainsize variations observed on the tephra deposit. The computational efficiency of the model is greatly enhanced by parallelizing the numerical model. Through inversion, we estimate the column height and total mass of the eruption as 6500m +/- 750m and 3.1 x 1010 kg +/- 2.9 x 109 kg respectively. These parameter ranges agree well with observations made during the 1992 Cerro Negro eruption: 7000-7500 m maximum column height and 2.3 x 1010 kg mass erupted. Parameter uncertainty, reported as one standard deviation from the mean, is estimated using a Monte Carlo method. Inversion techniques such as the downhill simplex method provide an unbiased method for utilizing volcanological observations to evaluate and improve numerical simulations of volcanic activity. Such an approach is essential for evaluating numerical models used

  14. Graphical method for forecasting radiation exposure from multi-aged fallout from nuclear weapons

    SciTech Connect

    Haaland, C.M.

    1986-06-01

    After a nuclear attack it may be necessary for emergency workers, such as firemen, utility workers and medical personnel, to perform urgent tasks in areas highly contaminated by radioactive fallout. To assist the control of radiation exposure of these workers, it will be useful to provide means to forecast radiation exposures both inside and outside the fallout shelter. The method described in this paper is intended for use during the first few days to weeks after the attack, after which time more sophisticated methods may become available. This method requires only a radiation-rate meter, special graph paper, and a timepiece. Communications with Emergency Operating Centers or other sources of information are not necessary. The method permits the determination of the age of fallout and future exposure rates for a location that might be subjected to a number of different fallout clouds, without requiring knowledge of the weapon yields or times of detonation. This method will provide results with less accuracy if different-aged fallout clouds arrive simultaneously. The method is self-correcting so that if the actual decay rate is different than that which is assumed, the forecasted rates will have less error than results obtained by previous methods.

  15. A graphical method for forecasting radiation exposure from multi-aged fallout from nuclear weapons.

    PubMed

    Haaland, C M

    1986-06-01

    After a nuclear attack it may be necessary for emergency workers, such as firemen, utility workers and medical personnel, to perform urgent tasks in areas highly contaminated by radioactive fallout. To assist the control of radiation exposure of these workers, it will be useful to provide means to forecast radiation exposures both inside and outside the fallout shelter. The method described in this paper is intended for use during the first few days to weeks after the attack, after which time more sophisticated methods may become available. This method requires only a radiation-rate meter, special graph paper, and a timepiece. Communications with Emergency Operating Centers or other sources of information are not necessary. The method permits the determination of the age of fallout and future exposure rates for a location that might be subjected to a number of different fallout clouds, without requiring knowledge of the weapon yields or times of detonation. This method will provide results with less accuracy if different-aged fallout clouds arrive simultaneously. The method is self-correcting so that if the actual decay rate is different than that which is assumed, the forecasted rates will have less error than results obtained by previous methods.

  16. A high resolution record of chlorine-36 nuclear-weapons-tests fallout from Central Asia

    USGS Publications Warehouse

    Green, J.R.; Cecil, L.D.; Synal, H.-A.; Santos, J.; Kreutz, K.J.; Wake, C.P.

    2004-01-01

    The Inilchek Glacier, located in the Tien Shan Mountains, central Asia, is unique among mid-latitude glaciers because of its relatively large average annual accumulation. In July 2000, two ice cores of 162 and 167 meters (m) in length were collected from the Inilchek Glacier for (chlorine-36) 36Cl analysis a part of a collaborative international effort to study the environmental changes archived in mid-latitude glaciers worldwide. The average annual precipitation at the collection site was calculated to be 1.6 m. In contrast, the reported average annual accumulations at the high-latitude Dye-3 glacial site, Greenland, the mid-latitude Guliya Ice Cap, China, and the mid-latitude Upper Fremont Glacier, Wyoming, USA, were 0.52, 0.16 and 0.76 m, respectively. The resolution of the 36Cl record in one of the Inilchek ice cores was from 2 to 10 times higher than the resolution of the records at these other sites and could provide an opportunity for detailed study of environmental changes that have occurred over the past 150 years. Despite the differences in accumulation among these various glacial sites, the 36Cl profile and peak concentrations for the Inilchek ice core were remarkably similar in shape and magnitude to those for ice cores from these other sites. The 36Cl peak concentration from 1958, the year during the mid-1900s nuclear-weapons-tests period when 36Cl fallout was largest, was preserved in the Inilchek core at a depth of 90.56 m below the surface of the glacier (74.14-m-depth water equivalent) at a concentration of 7.7 ?? 105 atoms of 36Cl/gram (g) of ice. Peak 36Cl concentrations from Dye-3, Guliya and the Upper Fremont glacial sites were 7.1 ?? 105, 5.4 ?? 105 and 0.7 ?? 105 atoms of 36Cl/g of ice, respectively. Measurements of 36Cl preserved in ice cores improve estimates of historical worldwide atmospheric deposition of this isotope and allow the sources of 36Cl in ground water to be better identified. ?? 2004 Published by Elsevier B.V.

  17. Atomic data from the Iron project. XIII. Electron excitation rates and emissivity ratios for forbidden transitions in NI II and Fe II.

    NASA Astrophysics Data System (ADS)

    Bautista, M. A.; Pradhan, A. K.

    1996-02-01

    Electron impact excitation rates and emissivity line ratios are reported for Optical and IR transitions in Ni II and Fe II arising from low-lying even parity levels. A total of 7 LS terms were included for Ni II, which result in 17 fine structure levels and 136 transitions. Coupling effects and resonance structures considered in the present calculations result in significant differences with the earlier distorted wave calculations by Nussbaumer & Storey (1982), although a reasonable agreement is found for the line diagnostics of some strong transitions in Ni II. Whereas an extensive set of collisional data has been presented earlier by Zhang & Pradhan for Fe II in the Iron Project series, in this paper we report collision strengths for some transitions missing from their dataset using an improved eigenfunction expansion for Fe II which includes the lowest 18 LS terms giving 52 fine structure levels and 1326 transitions. The present dataset provides a useful check on several forbidden transitions in Fe II and essentially confirms the diagnostics derived from the earlier work. The present calculations were carried out on the massively parallel processor Cray T3D with a parallelized version of the Iron Project R-matrix codes; to our knowledge these are the first such calculations.

  18. Plutonium and americium inventories in atmospheric fallout and sediment cores from Blelham Tarn, Cumbria (UK).

    PubMed

    Michel, H; Barci-Funel, G; Dalmasso, J; Ardisson, G; Appleby, P G; Haworth, E; El-Daoushy, F

    2002-01-01

    The objective of this paper is to report on the results of a study of 238Pu, 239 + 240Pu and 241Am inventories onto Blelham Tarn in Cumbria (UK). The atmospheric fallout inventory was obtained by analysing soil cores and the results are in good agreement with the literature: 101 Bq m(-2) for 239 + 240Pu; 4.5 Bq m(-2) for 238Pu and 37 Bq m(-2) for 241Am. The sediment core inventory for the whole lake is compared to the atmospheric fallout inventory. The sediment activity is 60-80% higher than the estimated fallout activity, showing a catchment area contribution and in particular the stream input.

  19. Observations of Fallout from the Fukushima Reactor Accident in San Francisco Bay Area Rainwater

    NASA Astrophysics Data System (ADS)

    Norman, Eric; Angell, Christopher; Chodash, Perry

    2011-10-01

    We observed fallout from the Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area beginning approximately 1 week after the earthquake. Gamma ray spectra measured from these samples show clear evidence of fission products - 131,132I, 132Te, and 134,137Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public. Soon after the observation of fallout in rainwater, we also observed low levels of Fukushima fallout in plant and food specimens collected in the the San Francisco area. This work was supported in part by the US Dept. of Homeland Security and by a Nuclear Non-Proliferation International Safeguards Graduate Fellowship (PAC) from the US Dept. of Energy.

  20. 137Cs in soil and fallout around Zagreb (Croatia) at the time of the Fukushima accident.

    PubMed

    Šoštarić, Marko; Petrinec, Branko; Babić, Dinko

    2013-12-01

    This paper addresses the noticeable increase of 137Cs activity concentrations in soil and fallout in the area surrounding Zagreb (Croatia) that occurred at the time of the 2011 Fukushima accident. This topic is important for public health as 137Cs is highly toxic due to its long half-life of radioactive decay and chemical similarity to potassium. 137Cs concentrations in fallout were much greater than in soil, but remained present longer in the latter. While being detectable in our measurements, 137Cs did not spread through the food chain in amounts exceeding the maximum allowed level of radioactive food contamination. However, more thorough and consistent measurements need to be done in order to establish the precise activity trends of 137Cs in Zagreb soil and fallout.

  1. Observation of gamma-rays from fallout collected at Ibaraki, Japan, during the Fukushima nuclear accident.

    PubMed

    Saegusa, Jun; Kikuta, Yasuaki; Akino, Hitoshi

    2013-07-01

    Gamma-ray pulse height distributions were measured for a fallout sample collected at Ibaraki, Japan, during the Fukushima accident in March 2011. The fallout was collected in a pan of water and then evaporated to dryness on a stainless-steel holder. The sample was measured by a germanium detector three times over a year. In the pulse height distribution of the initial measurement, approximately 140 peaks were observed in the 50-2048 keV energy region. Most of these peaks were either total absorption peaks or sum peaks of Te, I or Cs isotopes. Unlike fallout samples at the past nuclear accidents, nuclides such as Ce and Ru were not detected whereas (110m)Ag was prominently observed. The radioactivity concentration of (137)Cs was determined to be at least 1.4×10(4) Bq m(-2), approximately 14% of which was attributed to rainout.

  2. Time-averaged fluxes of lead and fallout radionuclides to sediments in Florida Bay

    USGS Publications Warehouse

    Robbins, J.A.; Holmes, C.; Halley, R.; Bothner, M.; Shinn, E.; Graney, J.; Keeler, G.; TenBrink, M.; Orlandini, K.A.; Rudnick, D.

    2000-01-01

    Recent, unmixed sediments from mud banks of central Florida Bay were dated using 210Pb/226Ra, and chronologies were verified by comparing sediment lead temporal records with Pb/Ca ratios in annual layers of coral (Montastrea annularis) located on the ocean side of the Florida Keys. Dates of sediment lead peaks (1978 ?? 2) accord with prior observations of a 6 year lag between the occurrence of maximum atmospheric lead in 1972 and peak coral lead in 1978. Smaller lags of 1-2 years occur between the maximum atmospheric radionuclide fallout and peaks in sediment temporal records of 137Cs and Pu. Such lags are consequences of system time averaging (STA) in which atmospherically delivered particle-associated constituents accumulate and mix in a (sedimentary?) reservoir before transferring to permanent sediments and coral. STA model calculations, using time-dependent atmospheric inputs, produced optimized profiles in excellent accord with measured sediment 137Cs, Pu, lead, and coral lead distributions. Derived residence times of these particle tracers (16 ?? 1, 15.7 ?? 0.7, 19 ?? 3, and 16 ?? 2 years, respectively) are comparable despite differences in sampling locations, in accumulating media, and in element loading histories and geochemical properties. For a 16 year weighted mean residence time, STA generates the observed 6 year lead peak lag. Evidently, significant levels of nondegradable, particle-associated contaminants can persist in Florida Bay for many decades following elimination of external inputs. Present results, in combination with STA model analysis of previously reported radionuclide profiles, suggest that decade-scale time averaging may occur widely in recent coastal marine sedimentary environments. Copyright 2000 by the American Geophysical Union.

  3. Federal Guidance Report No. 4: Estimates and Evaluation of Fallout in the United States from Nuclear Weapons Testing Conducted Through 1962

    EPA Pesticide Factsheets

    This Federal Radiation Council report includes a full study and analysis of fallout expected in 1963 from nuclear testing that occurred in the past. This report covers fallout expected from Soviet and United States tests through 1962.

  4. Fallout Deposition in the Marshall Islands from Bikini and Enewetak Nuclear Weapons Tests

    PubMed Central

    Beck, Harold L.; Bouville, André; Moroz, Brian E.; Simon, Steven L.

    2009-01-01

    Deposition densities (Bq m-2) of all important dose-contributing radionuclides occurring in nuclear weapons testing fallout from tests conducted at Bikini and Enewetak Atolls (1946-1958) have been estimated on a test-specific basis for all the 31 atolls and separate reef islands of the Marshall Islands. A complete review of various historical and contemporary data, as well as meteorological analysis, was used to make judgments regarding which tests deposited fallout in the Marshall Islands and to estimate fallout deposition density. Our analysis suggested that only 20 of the 66 nuclear tests conducted in or near the Marshall Islands resulted in substantial fallout deposition on any of the 25 inhabited atolls. This analysis was confirmed by the fact that the sum of our estimates of 137Cs deposition from these 20 tests at each atoll is in good agreement with the total 137Cs deposited as estimated from contemporary soil sample analyses. The monitoring data and meteorological analyses were used to quantitatively estimate the deposition density of 63 activation and fission products for each nuclear test, plus the cumulative deposition of 239+240Pu at each atoll. Estimates of the degree of fractionation of fallout from each test at each atoll, as well as of the fallout transit times from the test sites to the atolls were used in this analysis. The estimates of radionuclide deposition density, fractionation, and transit times reported here are the most complete available anywhere and are suitable for estimations of both external and internal dose to representative persons as described in companion papers. PMID:20622548

  5. Fallout deposition in the Marshall Islands from Bikini and Enewetak nuclear weapons tests.

    PubMed

    Beck, Harold L; Bouville, André; Moroz, Brian E; Simon, Steven L

    2010-08-01

    Deposition densities (Bq m(-2)) of all important dose-contributing radionuclides occurring in nuclear weapons testing fallout from tests conducted at Bikini and Enewetak Atolls (1946-1958) have been estimated on a test-specific basis for 32 atolls and separate reef islands of the Marshall Islands. A complete review of various historical and contemporary data, as well as meteorological analysis, was used to make judgments regarding which tests deposited fallout in the Marshall Islands and to estimate fallout deposition density. Our analysis suggested that only 20 of the 66 nuclear tests conducted in or near the Marshall Islands resulted in substantial fallout deposition on any of the 23 inhabited atolls. This analysis was confirmed by the fact that the sum of our estimates of 137Cs deposition from these 20 tests at each atoll is in good agreement with the total 137Cs deposited as estimated from contemporary soil sample analyses. The monitoring data and meteorological analyses were used to quantitatively estimate the deposition density of 63 activation and fission products for each nuclear test, plus the cumulative deposition of 239+240Pu at each atoll. Estimates of the degree of fractionation of fallout from each test at each atoll, as well as of the fallout transit times from the test sites to the atolls were used in this analysis. The estimates of radionuclide deposition density, fractionation, and transit times reported here are the most complete available anywhere and are suitable for estimations of both external and internal dose to representative persons as described in companion papers.

  6. Fallout from the Chernobyl nuclear disaster and congenital malformations in Europe.

    PubMed

    Hoffmann, W

    2001-01-01

    Investigators estimate that the population exposure that resulted from the Chernobyl fallout is in the range of natural background radiation for most European countries. Given current radiobiologic knowledge, health effects-if any-would not be measurable with epidemiologic tools. In several independent reports, however, researchers have described isolated peaks in the prevalence of congenital malformations in the cohort conceived immediately after onset of the fallout. The consistency of the time pattern and the specific types of malformation raise concern about their significance. In this study, the author summarizes findings from Turkey, Belarus, Croatia, Finland, Germany, and other countries, and implications for radiation protection and public health issues are discussed.

  7. Operation Hardtack. Project 2.8. Fallout Measurements by Aircraft and Rocket Sampling,

    DTIC Science & Technology

    1985-09-01

    42, 945-964; December 1956; Unclassified. 44. A. G. Hoard, Merrill Elsenbud and J. H. Harley ; " Annotated Bibliography on Fallout Resulting from...Hoard, Merrill Elsenbud and J. H. Harley ; "Annotated Bibliography on Long " Range Effects of Fallout from Nuclear Explosions" NYO-4753, Supplement 1...San Francisco, California; Secret Restricted Daca. 88 - .P S . .. . , , •i • • ’•’ • • •I• •l !" . I\\ 67. P.C. Svenaoe, z.0. Nicks , W.E. Nervik and IL

  8. Organizational and social-psychological issues relevant to fallout-shelter evaluation

    SciTech Connect

    Wernette, D.R.

    1983-01-01

    This paper presents the results of a preliminary review of the literature on organizational and social-psychological issues relevant to fallout-shelter evaluation. Fallout-shelter options are evaluated along two dimensions: shelter size, and extent of shelteree participation in the shelter construction. Four functional criteria are used in the evaluation: decision-making, member coordination, social control, and maintaining morale. Smaller shelters requiring shelteree participation in construction appear preferable as measured in most of these criteria. Additional factors mentioned include demographic characteristics of the shelter population, degree and type of ventilation system, and availability of medical equipment and personnel. 10 references.

  9. Development and validation of a new fallout transport method using variable spectral winds. Doctoral thesis

    SciTech Connect

    Hopkins, A.T.

    1984-09-01

    The purpose of this research was to develop and validate a fallout prediction method using variable transport calculations. The new method uses National Meteorological Center (NMC) spectral coefficients to compute wind vectors along the space- and time-varying trajectories of falling particles. The method was validated by comparing computed and actual cloud trajectories from a Mount St. Helens volcanic eruption and a high dust cloud. In summary, this research demonstrated the feasibility of using spectral coefficients for fallout transport calculations, developed a two-step smearing model to treat variable winds, and showed that uncertainties in spectral winds do not contribute significantly to the error in computed dose rate.

  10. Po-210 and Pb-210 as atmospheric tracers and global atmospheric Pb-210 fallout: a review.

    PubMed

    Baskaran, M

    2011-05-01

    Over the past ∼ 5 decades, the distribution of (222)Rn and its progenies (mainly (210)Pb, (210)Bi and (210)Po) have provided a wealth of information as tracers to quantify several atmospheric processes that include: i) source tracking and transport time scales of air masses; ii) the stability and vertical movement of air masses iii) removal rate constants and residence times of aerosols; iv) chemical behavior of analog species; and v) washout ratios and deposition velocities of aerosols. Most of these applications require that the sources and sink terms of these nuclides are well characterized. Utility of (210)Pb, (210)Bi and (210)Po as atmospheric tracers requires that data on the (222)Rn emanation rates is well documented. Due to low concentrations of (226)Ra in surface waters, the (222)Rn emanation rates from the continent is about two orders of magnitude higher than that of the ocean. This has led to distinctly higher (210)Pb concentrations in continental air masses compared to oceanic air masses. The highly varying concentrations of (210)Pb in air as well the depositional fluxes have yielded insight on the sources and transit times of aerosols. In an ideal enclosed air mass (closed system with respect to these nuclides), the residence times of aerosols obtained from the activity ratios of (210)Pb/(222)Rn, (210)Bi/(210)Pb, and (210)Po/(210)Pb are expected to agree with each other, but a large number of studies have indicated discordance between the residence times obtained from these three pairs. Recent results from the distribution of these nuclides in size-fractionated aerosols appear to yield consistent residence time in smaller-size aerosols, possibly suggesting that larger size aerosols are derived from resuspended dust. The residence times calculated from the (210)Pb/(222)Rn, (210)Bi/(210)Pb, and (210)Po/(210)Pb activity ratios published from 1970's are compared to those data obtained in size-fractionated aerosols in this decade and possible reasons for

  11. Radiological survey and evaluation of the fallout area from the Trinity test: Chupadera Mesa and White Sands Missile Range, New Mexico

    SciTech Connect

    Hansen, W.R.; Rodgers, J.C.

    1985-06-01

    Current radiological conditions were evaluated for the site of the first nuclear weapons test, the Trinity test, and the associated fallout zone. The test, located on White Sands Missile Range, was conducted as part of the research with nuclear materials for the World War II Manhattan Engineer District atomic bomb project. Some residual radioactivity attributable to the test was found in the soils of Ground Zero on White Sands Missile Range and the areas that received fallout from the test. The study considered relevant information including historical records, environmental data extending back to the 1940s, and new data acquired by field sampling and measurements. Potential exposures to radiation were evaluated for current land uses. Maximum estimated doses on Chupadera Mesa and other uncontrolled areas are less than 3% of the DOE Radiation Protection Standards (RPSs). Radiation exposures during visits to the US Army-controlled Ground Zero area are less than 1 mrem per annual visit or less than 0.2% of the RPS for a member of the public. Detailed data and interpretations are provided in appendixes. 14 figs., 45 tabs.

  12. Source Normalization Constants for Ground Distributed Fallout Fields

    DTIC Science & Technology

    2011-09-01

    Gamma Rays by Terrain Roughness by Herte. Using a Monte-Carlo code ( MORSE ) to model surface roughness, his results indicate self-shielding between 2...Atomic Nucleus. Krieger Publishing Company, 1955. 4. Glasstone, Samuel and Philip Dolan. The Effects of Nuclear Weapons. Washington, DC: U.S

  13. L X-ray production cross-section ratios for protons incident on high- Z atoms: A test of ECPSSR theory and newly recommended vacancy de-excitation parameters

    NASA Astrophysics Data System (ADS)

    Jones, B. N.; Campbell, J. L.

    2007-05-01

    The X-ray intensity ratios Lβ/Lα and Lγ/Lα for six heavy elements have been measured using a Si(Li) detector coupled to both analog and digital signal processors. The proton energies were chosen to ensure that possible united atom (UA) and intra-shell (IS) effects would be small, thereby ensuring that the experiments were a direct test of the ECPSSR together with the L subshell fluorescence and Coster-Kronig probabilities. Careful attention was paid to reducing recognized uncertainties in the fitting of the spectra, with the desired intensity ratios being extracted from a procedure that assumed the DF radiative transition rates of Scofield to be correct. Experiment and ECPSSR theory agree closely when the fluorescence and CK probabilities from a recent critical review are adopted in preference to those commonly used in earlier work. This result provides a significant improvement in the database used for PIXE analysis, and it paves the way for more definitive studies at lower proton energies, aimed at testing predicted UA and IS corrections.

  14. Incorporation of Hopkins variable wind model into a population-dose fallout code. Master's thesis

    SciTech Connect

    St. Ledger, J.W.

    1985-03-01

    Hopkins variable wind fallout model is used to predict the dose and population insult across the United States from a nuclear attack. The dose calculation is performed by two programs written in Fortran V for a CYBER 845 computer. Hopkins hotline locator program was modified to reduce its run time, and it is used to locate the fallout hotline as trace particles are translated to the ground in a spatially varying wind field. The second program analytically smears fallout activity along the hotline. To reduce run time and to match the population model, the dose program uses a computational grid of one degree latitude by one degree longitude. A difference of cumulative normal functions gives the average dose across a grid cell. An analytical method was developed to treat multiple bursts against an area target as one cloud. For the winds of 0000 Universal Time on 16 January 1982, a hypothetical attack against twenty-five air bases and six Minuteman missile fields results in 26.9 million fallout deaths. This calculation used 407 seconds of computer time.

  15. Graphic presentation of quarterly /sup 90/Sr fallout data, 1954-1982

    SciTech Connect

    Larsen, R.J.

    1984-01-01

    This report graphically presents all of the precipitation and /sup 90/Sr deposition data for all stations operated as part of the Environmental Measurements Laboratory's (EML) global fallout program since the initiation of the program in 1954. 3 references, 179 figures.

  16. Individual external exposures from Nevada Test Site fallout for Utah leukemia cases and controls.

    PubMed

    Lloyd, R D; Gren, D C; Simon, S L; Wrenn, M E; Hawthorne, H A; Lotz, T M; Stevens, W; Till, J E

    1990-11-01

    External gamma-ray exposures from fallout originating at the Nevada Test Site (NTS) have been assigned to 6,507 individual subjects (1,177 leukemia cases and 5,330 control subjects) who died as Utah residents between 1952 and 1981. Leukemia cases were identified, confirmed, and classified by cell type from the Utah Cancer Registry, Utah State vital records, and medical records. Residential histories were obtained from the Deceased Membership File (DMF) of the Church of Jesus Christ of Latter-day Saints (LDS), supplemented by information from the LDS Church Census Records that were taken in 1950, 1955, and 1960-62. Control subjects were selected randomly within age strata from the DMF and were frequency-matched to the cases by age at death and for sex. Individual radiation exposures were assigned as a function of residence location and time interval for each residence during the fallout period (1951-1958) using geographic exposure data taken from the literature. Temporal distribution of exposure for subjects who resided in more than one locality or who were born or died during the fallout period was determined from data of other investigators. Calculated gamma-ray exposures for each place of residence were summed for each subject to yield the exposure to fallout from the NTS.

  17. Preliminary evaluation of crisis-relocation fallout-shelter options. Volume 2. Detailed analysis

    SciTech Connect

    Santini, D.J.; Clinch, J.M.; Davis, F.H.; Hill, L.G.; Lynch, E.P.; Tanzman, E.A.; Wernette, D.R.

    1982-12-01

    This report presents a preliminary, detailed evaluation of various shelter options for use if the President orders crisis relocation of the US urban population because of strong expectation of a nuclear war. The availability of livable shelter space at 40 ft/sup 2/ per person (congregate-care space) by state is evaluated. Options are evaluated for construction of fallout shelters allowing 10 ft/sup 2/ per person - such shelters are designed to provide 100% survival at projected levels of radioactive fallout. The FEMA concept of upgrading existing buildings to act as fallout shelters can, in principle, provide adequate shelter throughout most of the US. Exceptions are noted and remedies proposed. In terms of upgrading existing buildings to fallout shelter status, great benefits are possible by turning away from a standard national approach and adopting a more site-specific approach. Existing FEMA research provides a solid foundation for successful crisis relocation planning, but the program can be refined by making suitable modifications in its locational, engineering, and institutionally specific elements.

  18. Individual external exposures from Nevada Test Site fallout for Utah leukemia cases and controls

    SciTech Connect

    Lloyd, R.D.; Gren, D.C.; Simon, S.L.; Wrenn, M.E.; Hawthorne, H.A.; Lotz, T.M.; Stevens, W.; Till, J.E. )

    1990-11-01

    External gamma-ray exposures from fallout originating at the Nevada Test Site (NTS) have been assigned to 6,507 individual subjects (1,177 leukemia cases and 5,330 control subjects) who died as Utah residents between 1952 and 1981. Leukemia cases were identified, confirmed, and classified by cell type from the Utah Cancer Registry, Utah State vital records, and medical records. Residential histories were obtained from the Deceased Membership File (DMF) of the Church of Jesus Christ of Latter-day Saints (LDS), supplemented by information from the LDS Church Census Records that were taken in 1950, 1955, and 1960-62. Control subjects were selected randomly within age strata from the DMF and were frequency-matched to the cases by age at death and for sex. Individual radiation exposures were assigned as a function of residence location and time interval for each residence during the fallout period (1951-1958) using geographic exposure data taken from the literature. Temporal distribution of exposure for subjects who resided in more than one locality or who were born or died during the fallout period was determined from data of other investigators. Calculated gamma-ray exposures for each place of residence were summed for each subject to yield the exposure to fallout from the NTS.

  19. New insights on using fallout radionuclides to estimate soil redistribution rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fallout radionuclides such as 137Cs have been widely accepted and used in the past 40 years to provide quantitative soil redistribution estimates at a point scale. Recently their usefulness has been questioned by a few researchers challenging the validity of the key assumption that the spatial ...

  20. VULNERABILITY OF HEADWATER CATCHMENT RESOURCES TO INCIDENCES OF 210PB EXCESS AND 137CS RADIONUCLIDE FALLOUT

    EPA Science Inventory

    Recent identification of elevated excess 210Pb (≤302.6 mBq L-1) and 137Cs (≤ 111.3 mBq L-1) activity in drinking water wells up to 20 m depth indicates some transport of airborne radionuclide fallout beyond soils in the Shaker Village c...

  1. Using Radioactive Fallout Cesium (137Cs) to Distinguish Sediment Sources in an Agricultural Watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Radioactive fallout Cesium (Cs-137) has been used for quantifying sources of accumulating sediment in water bodies and to determine the rates and pattern of soil erosion. The objectives of this research are to use Cs-137 as a tracer to determine patterns of soil erosion and deposition of eroding soi...

  2. Using fallout Cesium-137 to understand soil redistribution over agricultural landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While it is recognized that soil erosion is highly variable in space and time, studies of the redistribution of soil within a field or watershed are limited. Our studies focus on the use of fallout Cesium-137 to understand pattern of soil movement on the landscape. It is often assumed that eroding...

  3. Using Fallout Cesium-137 to understand soil redistribution over agricultural landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While it is recognized that soil erosion is highly variable in space and time, studies of the redistribution of soil and soil organic carbon (SOC) within a field or watershed are limited. Our studies focus on the use of fallout Cesium-137 to understand pattern of soil and SOC movement on the landsca...

  4. In Utero Exposure to Iodine-131 from Chernobyl Fallout and Anthropometric Characteristics in Adolescence

    PubMed Central

    Neta, Gila; Hatch, Maureen; Kitahara, Cari M.; Ostroumova, Evgenia; Bolshova, Elena V.; Tereschenko, Valery P.; Tronko, Mykola D.; Brenner, Alina V.

    2014-01-01

    Prenatal exposure to external radiation has been linked to growth retardation among atomic bomb survivors in adolescence. It is unclear from previous studies whether in utero exposure to internal radiation such as iodine-131 (I-131), which concentrates in the thyroid gland, has an effect on physical growth. We examined the associations between estimated thyroid gland dose from prenatal exposure to I-131 and self-reported height and weight in a cohort of 2,460 individuals exposed to radioactive fallout from the 1986 Chernobyl nuclear accident [mean I-131 dose = 72 (mGy)] and screened for thyroid diseases in adolescence. Using multivariable linear regression models, we estimated the mean differences in height, weight and body mass index (BMI) per unit increase in dose (100 mGy) in models adjusted for gender, age at examination, type of residence (rural/urban) and presence of thyroid disease diagnosed at screening. All of the adjustment factors as well as the trimester of exposure were evaluated as potential modifiers of the dose response. Overall, no significant dose response was found for height (P = 0.29), weight (P = 0.14) or BMI (P = 0.16). We found significant modification of the dose response for weight and BMI by presence/absence of thyroid disease (P = 0.02 and P = 0.03, respectively), but not for other factors. In individuals without thyroid disease (n = 1,856), there was a weak, significant association between I-131 thyroid dose and higher weight (210 g per 100 mGy, P = 0.02) or BMI (70 g/m2 per 100 mGy, P = 0.02) that depended on individuals (n = 52) exposed to ≥500 mGy. In individuals with thyroid disease (n = 579, 67.4% with simple diffuse goiter) no significant association with I-131 for weight (P = 0.14) or BMI (P = 0.14) was found. These results do not support the hypothesis that in utero exposure to I-131 at levels experienced by a majority of study subjects may be associated with meaningful differences in adolescent anthropometry. However

  5. New technologies to improve the monitoring of tephra fallouts from Etna: the collaborative system Tefranet

    NASA Astrophysics Data System (ADS)

    Andronico, Daniele; Ferrari, Ferruccio; Merenda, Riccardo; Reitano, Danilo; Scollo, Simona; Cristaldi, Antonio; Lodato, Luigi; Mangiagli, Salvatore

    2016-04-01

    During early December 2015, Mt. Etna (Italy) produced 4 paroxysmal events from the Voragine crater in just 3 days. This activity caused ash and lapilli fallout over a wide area extending from the volcanic slopes up to ~100 km from the volcano, affecting numerous villages and the cities of Messina and Reggio Calabria. Monitoring this kind of volcanic activity in order to know the dispersal of tephra fallout in quasi-real time can prove challenging, especially when several paroxysmal events follow each other as during these latest eruptions in December. To tackle similar recurring periods of frequent activity, which have occurred a number of times at Etna over recent years, we devised a collaborative system named Tefranet. The system is easy to use but at the same time designed to rapidly retrieve useful georeferenced information on tephra fallouts from Etna's explosive activity. Tefranet includes a mobile application and a web site, with particular attention to an administration backend tool, making owners of smartphones or other mobile devices participants. The system aims to involve citizens living not only in eastern Sicily (i.e. the area most affected by fallout based on the prevailing winds blowing on Etna), but also those resident at some distance, in areas potentially covered by tephra (more than 60-80 km from the volcano) and that are difficult to reach before the original amounts of tephra on the ground may become altered by anthropic (e.g. car traffic) and atmospheric (wind and rain) factors. The Tefranet community will be informed by the INGV specialists via mobile device in case explosive activity resumes, with users able to visualize all the tephra signals on a map in real time. All kinds of information concerning start/end of the tephra fallout, estimation of the clast dimensions, thickness of the deposit, level of tephra cover on the ground, will be welcomed, especially if accompanied by photos of the deposit and of the eruption plume. Here, we

  6. Fallout radionuclide-based techniques for assessing the impact of soil conservation measures on erosion control and soil quality: an overview of the main lessons learnt under an FAO/IAEA Coordinated Research Project.

    PubMed

    Dercon, G; Mabit, L; Hancock, G; Nguyen, M L; Dornhofer, P; Bacchi, O O S; Benmansour, M; Bernard, C; Froehlich, W; Golosov, V N; Haciyakupoglu, S; Hai, P S; Klik, A; Li, Y; Lobb, D A; Onda, Y; Popa, N; Rafiq, M; Ritchie, J C; Schuller, P; Shakhashiro, A; Wallbrink, P; Walling, D E; Zapata, F; Zhang, X

    2012-05-01

    This paper summarizes key findings and identifies the main lessons learnt from a 5-year (2002-2008) coordinated research project (CRP) on "Assessing the effectiveness of soil conservation measures for sustainable watershed management and crop production using fallout radionuclides" (D1.50.08), organized and funded by the International Atomic Energy Agency through the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The project brought together nineteen participants, from Australia, Austria, Brazil, Canada, Chile, China, Japan, Morocco, Pakistan, Poland, Romania, Russian Federation, Turkey, United Kingdom, United States of America and Vietnam, involved in the use of nuclear techniques and, more particularly, fallout radionuclides (FRN) to assess the relative impacts of different soil conservation measures on soil erosion and land productivity. The overall objective of the CRP was to develop improved land use and management strategies for sustainable watershed management through effective soil erosion control practices, by the use of ¹³⁷Cs (half-life of 30.2 years), ²¹⁰Pb(ex) (half-life of 22.3 years) and ⁷Be (half-life of 53.4 days) for measuring soil erosion over several spatial and temporal scales. The environmental conditions under which the different research teams applied the tools based on the use of fallout radionuclides varied considerably--a variety of climates, soils, topographies and land uses. Nevertheless, the achievements of the CRP, as reflected in this overview paper, demonstrate that fallout radionuclide-based techniques are powerful tools to assess soil erosion/deposition at several spatial and temporal scales in a wide range of environments, and offer potential to monitor soil quality. The success of the CRP has stimulated an interest in many IAEA Member States in the use of these methodologies to identify factors and practices that can enhance sustainable agriculture and minimize land degradation.

  7. Quantifying Atmospheric Fallout of Fukushima-derived Radioactive Isotopes in the Hawaiian Islands

    NASA Astrophysics Data System (ADS)

    McKenzie, Trista; Dulai, Henrietta

    2016-04-01

    On March 11, 2011, several reactors at the Fukushima Dai-ichi Nuclear Power Plant suffered damage and released the radioisotopes iodine-131, cesium-134, and cesium-137 into the atmosphere. A week later, these isotopes were detected in aerosols over the state of Hawaii and in milk samples analyzed from the Big Island. Because the detected levels were significantly below levels of health concern, the state did not attempt to quantify the deposition of these nuclides on the islands. This study estimated the magnitude of atmospheric fallout of cesium and iodine, and examined the patterns of cesium wet deposition with precipitation observed in March 2011. Mushroom and soil samples were collected along precipitation gradients on Oahu and the island of Hawaii and analyzed for cesium isotopes using gamma spectrometry. Fukushima-derived fallout was differentiated from historic nuclear weapons testing fallout by the presence of Cs-134, which has a shorter half-life of 2.06 years and the fact that Cs-134 and 137 were released from the severed power plant nearly in parity. We found that Fukushima-derived cesium was present in both mushrooms and soil and the soil inventories ranged 2.2-60.9 Bq/m2 for Cs-137 and 16.1-445.8 Bq/m2 for I-131. Additionally, we found that Fukushima-derived cesium inventories in soils were correlated with precipitation gradients. This research confirmed and quantified the presence of Fukushima-derived fallout in Hawaii, however the activities detected were orders of magnitude lower than fallout associated with the nuclear weapons testing in the Pacific.

  8. A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

    DOE PAGES

    Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; ...

    2016-12-15

    Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

  9. A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

    SciTech Connect

    Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; Zimmer, Mindy M.; Pollington, Anthony D.; Rector, Kirk D.

    2016-12-15

    Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.

  10. A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

    NASA Astrophysics Data System (ADS)

    Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; Zimmer, Mindy M.; Pollington, Anthony D.; Rector, Kirk D.

    2017-01-01

    Glassy nuclear fallout debris from near-surface nuclear tests is fundamentally reprocessed earth material. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. This study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test ("trinitite") and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. The volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.

  11. Dual-core mass-balance approach for evaluating mercury and 210Pb atmospheric fallout and focusing to lakes.

    PubMed

    Van Metre, Peter C; Fuller, Christopher C

    2009-01-01

    Determining atmospheric deposition rates of mercury and other contaminants using lake sediment cores requires a quantitative understanding of sediment focusing. Here we present a novel approach that solves mass-balance equations fortwo cores algebraicallyto estimate contaminant contributions to sediment from direct atmospheric fallout and from watershed and in-lake focusing. The model is applied to excess 210Pb and Hg in coresfrom Hobbs Lake, a high-altitude lake in Wyoming. Model results for excess 210Pb are consistent with estimates of fallout and focusing factors computed using excess 210Pb burdens in lake cores and soil cores from the watershed and model results for Hg fallout are consistent with fallout estimated using the soil-core-based 210Pb focusing factors. The lake cores indicate small increases in mercury deposition beginning in the late 1800s and large increases after 1940, with the maximum at the tops of the cores of 16-20 microg/m2 x year. These results suggest that global Hg emissions and possibly regional emissions in the western United States are affecting the north-central Rocky Mountains. Hg fallout estimates are generally consistent with fallout reported from an ice core from the nearby Upper Fremont Glacier, but with several notable differences. The model might not work for lakes with complex geometries and multiple sediment inputs, but for lakes with simple geometries, like Hobbs, it can provide a quantitative approach for evaluating sediment focusing and estimating contaminant fallout.

  12. Dual-core mass-balance approach for evaluating mercury and210Pb atmospheric fallout and focusing to lakes

    USGS Publications Warehouse

    Van Metre, P.C.; Fuller, C.C.

    2009-01-01

    Determining atmospheric deposition rates of mercury and other contaminants using lake sediment cores requires a quantitative understanding of sediment focusing. Here we present a novel approach that solves mass-balance equations for two cores algebraically to estimate contaminant contributions to sediment from direct atmospheric fallout and from watershed and in-lake focusing. The model is applied to excess 210Pb and Hg in cores from Hobbs Lake, a high-altitude lake in Wyoming. Model results for excess 210Pb are consistent with estimates of fallout and focusing factors computed using excess 210Pb burdens in lake cores and soil cores from the watershed and model results for Hg fallout are consistent with fallout estimated using the soil-core-based 210Pb focusing factors. The lake cores indicate small increases in mercury deposition beginning in the late 1800s and large increases after 1940, with the maximum at the tops of the cores of 16-20 ??g/m 2year. These results suggest that global Hg emissions and possibly regional emissions in the western United States are affecting the north-central Rocky Mountains. Hg fallout estimates are generally consistent with fallout reported from an ice core from the nearby Upper Fremont Glacier, but with several notable differences. The model might not work for lakes with complex geometries and multiple sediment inputs, but for lakes with simple geometries, like Hobbs, it can provide a quantitative approach for evaluating sediment focusing and estimating contaminant fallout.

  13. Determination of 240Pu/239Pu isotopic ratios in human tissues collected from areas around the Semipalatinsk Nuclear Test Site by sector-field high resolution ICP-MS.

    PubMed

    Yamamoto, M; Oikawa, S; Sakaguchi, A; Tomita, J; Hoshi, M; Apsalikov, K N

    2008-09-01

    Information on the 240Pu/239Pu isotope ratios in human tissues for people living around the Semipalatinsk Nuclear Test Site (SNTS) was deduced from 9 sets of soft tissues and bones, and 23 other bone samples obtained by autopsy. Plutonium was radiochemically separated and purified, and plutonium isotopes (239Pu and 240Pu) were determined by sector-field high resolution inductively coupled plasma-mass spectrometry. For most of the tissue samples from the former nine subjects, low 240Pu/239Pu isotope ratios were determined: bone, 0.125 +/- 0.018 (0.113-0.145, n = 4); lungs, 0.063 +/- 0.010 (0.051-0.078, n = 5); and liver, 0.148 +/- 0.026 (0.104-0.189, n = 9). Only 239Pu was detected in the kidney samples; the amount of 240Pu was too small to be measured, probably due to the small size of samples analyzed. The mean 240Pu/239Pu isotope ratio for bone samples from the latter 23 subjects was 0.152 +/- 0.034, ranging from 0.088 to 0.207. A significant difference (a two-tailed Student's t test; 95% significant level, alpha = 0.05) between mean 240Pu/239Pu isotope ratios for the tissue samples and for the global fallout value (0.178 +/- 0.014) indicated that weapons-grade plutonium from the atomic bombs has been incorporated into the human tissues, especially lungs, in the residents living around the SNTS. The present 239,240Pu concentrations in bone, lung, and liver samples were, however, not much different from ranges found for human tissues from other countries that were due solely to global fallout during the 1970's-1980's.

  14. Influence of copper to indium atomic ratio on the properties of Cu-In-Te based thin-film solar cells prepared by low-temperature co-evaporation

    SciTech Connect

    Mise, Takahiro; Nakada, Tokio

    2012-09-15

    The influence of copper to indium atomic ratio (Cu/In) on the properties of Cu-In-Te based thin films and solar cells was investigated. The films (Cu/In = 0.38-1.17) were grown on both bare and Mo-coated soda-lime glass substrates at 250 Degree-Sign C by single-step co-evaporation using a molecular beam epitaxy system. Highly (112)-oriented CuInTe{sub 2} films were obtained at Cu/In ratios of 0.84-0.99. However, stoichiometric and Cu-rich films showed a poor film structure with high surface roughness. The films consist of polyhedron-shaped grains, which are related to the coexistence of a Cu{sub 2-x}Te phase, and significant evidence for the coexistence of the Cu{sub 2-x}Te phase in the stoichiometric and Cu-rich films is presented. KCN treatment was performed for the films in order to remove the Cu{sub 2-x}Te phase. The stoichiometric CuInTe{sub 2} thin films exhibited a high mobility above 50 cm{sup 2}/V s at room temperature after the KCN treatment. A preliminary solar cell fabricated using a 1.4-{mu}m-thick Cu-poor CuInTe{sub 2} thin film (Cu/In = 0.84, E{sub g} = 0.988 eV) yielded a total-area efficiency of 2.10%. The photovoltaic performance of the cell was improved after long-term ambient aging in dark conditions.

  15. Implementation of a new atomic basis for the He I equilibrium line ratio technique for electron temperature and density diagnostic in the SOL for H-mode plasmas in DIII-D

    SciTech Connect

    Burgos, JMM; Schmitz, O.; Unterberg, Ezekial A; Loch, S. D.; Ballance, C. P.

    2011-01-01

    Evaluating the ratio of selected helium lines allows for measurement of electron densities and temperatures. This technique is applied for L-mode plasmas at TEXTOR (O. Schmitz et al., Plasma Phys. Control. Fusion 50 (2008) 115004). We report our first efforts to extend it to H-mode plasma diagnostics in DIII-D. This technique depends on the accuracy of the atomic data used in the collisional radiative model (CRM). We present predictions for the electron temperatures and densities by using recently calculated R-Matrix With Pseudostates (RMPS) and Convergent Close-Coupling (CCC) electron-impact excitation and ionization data. We include contributions from higher Rydberg states by means of the projection matrix. These effects become significant for high electron density conditions, which are typical in H-mode. We apply a non-equilibrium model for the time propagation of the ionization balance to predict line emission profiles from experimental H-mode data from DIII-D. (C) 2010 Elsevier B.V. All rights reserved.

  16. High-level direct-dynamics variational transition state theory calculations including multidimensional tunneling of the thermal rate constants, branching ratios, and kinetic isotope effects of the hydrogen abstraction reactions from methanol by atomic hydrogen.

    PubMed

    Meana-Pañeda, Rubén; Truhlar, Donald G; Fernández-Ramos, Antonio

    2011-03-07

    We report a detailed theoretical study of the hydrogen abstraction reaction from methanol by atomic hydrogen. The study includes the analysis of thermal rate constants, branching ratios, and kinetic isotope effects. Specifically, we have performed high-level computations at the MC3BB level together with direct dynamics calculations by canonical variational transition state theory (CVT) with the microcanonically optimized multidimensional tunneling (μOMT) transmission coefficient (CVT/μOMT) to study both the CH(3)OH+H→CH(2)OH+H(2) (R1) reaction and the CH(3)OH+H→CH(3)O+H(2) (R2) reaction. The CVT/μOMT calculations show that reaction R1 dominates in the whole range 298≤T (K)≤2500 and that anharmonic effects on the torsional mode about the C-O bond are important, mainly at high temperatures. The activation energy for the total reaction sum of R1 and R2 reactions changes substantially with temperature and, therefore, the use of straight-line Arrhenius plots is not valid. We recommend the use of new expressions for the total R1 + R2 reaction and for the R1 and R2 individual reactions.

  17. Determination of the 243 Cm/244 Cm ratio alpha spectrometry and spectral deconvolution in environmental samples exposed to discharges from the nuclear fuel cycle.

    PubMed

    Mitchell, P I; Holm, E; León Vintró, L; Condren, O M; Roos, P

    1998-01-01

    The presence of curium nuclides in irradiated nuclear fuel is well known, as is their occurrence in environmental materials exposed to liquid waste discharges from reprocessing plants and to fallout following the Chernobyl accident. Knowledge of the 242 Cm/244 Cm and 243 Cm/244 Cm atom ratios can be a useful tool for characterizing a source-term and assessing the burn-up history of nuclear fuel. Here, a practical technique, based on high-resolution alpha spectrometry and spectral deconvolution, is described by which the 243, 244 Cm multiplet can be resolved at the low activities typical of most environmental samples. The resulting 243 Cm/244 Cm ratio is then used to correct for any interference by 243 Cm in the 242 Cm window. The technique has been applied to the determination of the 243 Cm/244 Cm ratio in samples of seabed sediment collected near the Sellafield outfall, riverine sediment sampled downstream of the Mayak reprocessing plant and soil and lichen from within the Chernobyl exclusion zone. Near Sellafield, the 243 Cm/244 Cm ratio was found to be < 2%, while near Mayak and Chernobyl it was considerably higher, being approximately 6-8%.

  18. "A Is for Atom, B Is for Bomb": Civil Defense in American Public Education, 1948-1963.

    ERIC Educational Resources Information Center

    Brown, JoAnne

    1988-01-01

    Discusses the development of civil defense education following World War II. Examines its effects on the public as atomic bomb drills became commonplace in schools which also served as fallout shelters. Concludes that inadequate portrayal of the horrors of nuclear war produced anger, fear, and disillusionment as the postwar generation matured.…

  19. The development of field-based measurement methods for radioactive fallout assessment.

    PubMed

    Miller, Kevin M; Larsen, Richard J

    2002-05-01

    An overview is provided on the development of field equipment, instrument systems, and methods of analyses that were used to assess the impact of radioactive fallout from atmospheric weapons tests. Included in this review are developments in fallout collection, aerosols measurements in surface air, and high-altitude sampling with aircraft and balloons. In addition, developments in radiation measurements are covered in such areas as survey and monitoring instruments, in situ gamma-ray spectrometry, and aerial measurement systems. The history of these developments and the interplay with the general advances in the field of radiation and radioactivity metrology are highlighted. An emphasis is given as to how the modifications and improvements in the instruments and methods over time led to their adaptation to present-day applications to radiation and radioactivity measurements.

  20. Extended Monitoring of Radioactive Fallout from the Fukushima Reactor Incident in a Variety of Media

    NASA Astrophysics Data System (ADS)

    Thomas, Keenan; Norman, Eric; Smith, Al; Angell, Christopher; Chodash, Perry; Lo, Boris; Hurley, Donna; Chan, Yuen-Dat

    2013-04-01

    We have observed fallout from the Fukushima Dai-ichi reactor accident in March of 2011 in samples of rainwater and a variety of air filters collected in the San Francisco Bay area and Northern California. Gamma ray spectra measured from the rain samples showed clear evidence of fission products - 131,132I, 132Te, and 134,137Cs. The activity levels measured for these isotopes were very low and posed no health risk to the public or environment. Additional testing was performed upon these rainwater samples in 2012 to also investigate the presence of 90Sr-which was not detected and a detection limit was determined. Also presented will be a separate set of gamma ray measurements of Fukushima fallout that has been tracked on a variety of media-rainwater, air filters, and automobile filters; throughout 2011 and 2012.

  1. Multifractal analysis of the 137Cs fallout pattern in Austria resulting from the Chernobyl accident.

    PubMed

    Pausch, G; Bossew, P; Hofmann, W; Steger, F

    1998-06-01

    The cumulative deposition of the 137Cs fallout in Austria resulting from the passage of the Chernobyl cloud has been investigated by applying correlation dimension and hyperbolic frequency distribution methods. For the analysis, a total of 1,881 deposition values were used, which were collected by the Federal Environmental Agency of Austria and the Federal Ministry of Health, representing all available measurements of 137Cs in soil made in Austria after the Chernobyl accident. From these data a hyperbolic exponent for the frequency distribution of 4.0 and a set of fractal correlation dimensions, which decrease from 1.426 +/- 0.022 (for the whole network) to 0.706 +/- 0.047 (for 137Cs values > or = 100 kBq m(-2)), were derived, thus confirming that the fallout pattern can be described as a multifractal.

  2. A preliminary study of the particulate fallout from the space shuttle (STS-1)

    NASA Technical Reports Server (NTRS)

    Hudson, G. M.

    1982-01-01

    Prediction of acid fallout and the dry deposition of Al2O2 was the objective of this investigation. Sampling was done at the Kennedy Space Center in Florida. The models available were not appropriate and the data available was negligible. Thus, a bimodal particle distribution was assumed normalized to the few existing data points and used as a foundation for a crude zeroth order approximation for the acid fallout. In addition, a settling spectrum for the Al2O3 particles was devised as a table look-up since the graphs in the literature at first pass could not be fitted with reasonable analytic functions. Consulting services were rendered to researchers. Special emphasis was placed on improving current techniques and adding LIDAR (Light Radar). Suggestions for future studies are made.

  3. Vertical migration studies of 137Cs from nuclear weapons fallout and the Chernobyl accident.

    PubMed

    Almgren, S; Isaksson, M

    2006-01-01

    The vertical migration of (137)Cs originating from nuclear weapons fallout (NWF) and the Chernobyl accident has been studied at 33 sampling sites in western Sweden. An attempt to describe the present depth distribution with a solution to the convection-diffusion equation (CDE) with a pulse-like fallout event as the initial condition was made. A sum of two CDEs describing the NWF and Chernobyl debris was fitted to the actual depth profiles measured by soil sampling. The fitted depth profiles were used to correct in situ measurements for the actual depth distribution, showing good agreement with the accumulated activities in soil samples. As expected, the vertical migration was very slow and most caesium was still present in the upper soil layers. The ranges of the apparent convection velocity, v, and apparent diffusion coefficient, D, were between 0 and 0.35 cm/year and 0.06 and 2.63 cm(2)/year, respectively.

  4. Relative effectiveness of structures as protection from gamma radiation from cloud and fallout sources as a function of source energy

    SciTech Connect

    Fingerlos, J.P.

    1984-01-01

    In the event of a release of radioactive material, it is necessary to know the doses the public could receive in order to make decisions that minimize the public's risk. In order to determine what doses the public might receive if they try to evacuate or seek shelter, it is necessary to know how much protection structures such as homes and vehicles provide. This information is well known only for a few gamma ray spectra, such as that from weapon fallout. The research reported here transfers the knowledge gained from the previous weapon-fallout shielding work to realistic protection factors for possible accidental releases whatever the released spectrum might be. Point kernel models were developed for both the fallout and cloud sources. That development included a method of accurately combining buildup factors in multi-region problems over wide ranges of energy and photon mean free path. A generalized method for calculating the effect of ground roughness on the attentuation factor for fallout sources was also developed. The results were reported for the 1-hr weapon fallout, and TMI-2 cloud and fallout spectra, as well as for discrete energies from 15 KeV to 15 MeV. The structures given as examples include small wood frame and large brick houses.

  5. Review of methods of dose estimation for epidemiological studies of the radiological impact of nevada test site and global fallout.

    PubMed

    Beck, Harold L; Anspaugh, Lynn R; Bouville, André; Simon, Steven L

    2006-07-01

    Methods to assess radiation doses from nuclear weapons test fallout have been used to estimate doses to populations and individuals in a number of studies. However, only a few epidemiology studies have relied on fallout dose estimates. Though the methods for assessing doses from local and regional compared to global fallout are similar, there are significant differences in predicted doses and contributing radionuclides depending on the source of the fallout, e.g. whether the nuclear debris originated in Nevada at the U.S. nuclear test site or whether it originated at other locations worldwide. The sparse historical measurement data available are generally sufficient to estimate external exposure doses reasonably well. However, reconstruction of doses to body organs from ingestion and inhalation of radionuclides is significantly more complex and is almost always more uncertain than are external dose estimates. Internal dose estimates are generally based on estimates of the ground deposition per unit area of specific radionuclides and subsequent transport of radionuclides through the food chain. A number of technical challenges to correctly modeling deposition of fallout under wet and dry atmospheric conditions still remain, particularly at close-in locations where sizes of deposited particles vary significantly over modest changes in distance. This paper summarizes the various methods of dose estimation from weapons test fallout and the most important dose assessment and epidemiology studies that have relied on those methods.

  6. Development and Validation of a New Fallout Transport Method Using Variable Spectral Winds

    NASA Astrophysics Data System (ADS)

    Hopkins, Arthur Thomas

    A new method has been developed to incorporate variable winds into fallout transport calculations. The method uses spectral coefficients derived by the National Meteorological Center. Wind vector components are computed with the coefficients along the trajectories of falling particles. Spectral winds are used in the two-step method to compute dose rate on the ground, downwind of a nuclear cloud. First, the hotline is located by computing trajectories of particles from an initial, stabilized cloud, through spectral winds, to the ground. The connection of particle landing points is the hotline. Second, dose rate on and around the hotline is computed by analytically smearing the falling cloud's activity along the ground. The feasibility of using specgtral winds for fallout particle transport was validated by computing Mount St. Helens ashfall locations and comparing calculations to fallout data. In addition, an ashfall equation was derived for computing volcanic ash mass/area on the ground. Ashfall data and the ashfall equation were used to back-calculate an aggregated particle size distribution for the Mount St. Helens eruption cloud. Further validation was performed by comparing computed and actual trajectories of a high explosive dust cloud (DIRECT COURSE). Using an error propagation formula, it was determined that uncertainties in spectral wind components produce less than four percent of the total dose rate variance. In summary, this research demonstrated the feasibility of using spectral coefficients for fallout transport calculations, developed a two-step smearing model to treat variable winds, and showed that uncertainties in spectral winds do not contribute significantly to the error in computed dose rate.

  7. Serologic markers for hepatitis B among Marshallese accidentally exposed to fallout radiation in 1954

    SciTech Connect

    Adams, W.H.; Fields, H.A.; Engle, J.R.; Hadler, S.C.

    1986-10-01

    At least one serologic marker of prior hepatitis B infection (hepatitis B surface antigen, antibody to surface antigen, or antibody to core antigen) was found in 91.7% of 314 Marshallese tested. The prevalence of hepatitis B surface antigenemia (3.3%) in a subpopulation that had resided on Rongelap Atoll at the time of accidental exposure to radioactive fallout from a thermonuclear test in 1954 did not differ significantly from the prevalence in a selected unexposed population (10.5%).

  8. A Dynamic Approach to Monitoring Particle Fallout in a Cleanroom Environment

    NASA Technical Reports Server (NTRS)

    Perry, Radford L., III

    2010-01-01

    This slide presentation discusses a mathematical model to monitor particle fallout in a cleanroom. "Cleanliness levels" do not lead to increases with regards to cleanroom type or time because the levels are not linear. Activity level, impacts the cleanroom class. The numerical method presented leads to a simple Class-hour formulation, that allows for dynamic monitoring of the particle using a standard air particle counter.

  9. Transfer of fallout radionuclides by Fukushima NPP accident from tree crown to forest ecosystem

    NASA Astrophysics Data System (ADS)

    Onda, Y.; Kato, H.; Wakahara, T.; Kawamori, A.; Tsujimura, M.

    2011-12-01

    Radioactive contamination has been detected in Fukushima and the neighboring prefectures due to the nuclear accident at Fukushima Daiichi Nuclear Power Plant (NPP) following the earthquake and tsunami on 11 March 2011. The total deposition of radioactive materials in fallout samples for 137Cs ranged from 0.02to >10 M Bq/m2 for Cs-137. Experimental catchments have been established in Yamakiya district, Kawamata Town, Fukushima prefecture, located about 35 km from Fukushima power plant, and designated as the evacuated zone. Approximate Cs-137 fallout in this area is 200-600k Bq/m2. We established 3 forest sites: broad leaf tree forest and two Japanese cedar forest plantation (young and mature). In each site we installed towers of 8-12 meters. Using these towers, we sampled tree leaves, and measure Cs-137 and Cs-134 in the laboratory, and also we have measure Cs-137, Cs-134 content at various height in each forest using a portable High Purity Germanium (HPGe) detector (Ortech; Detective-EX). We also measured the throughfall, stem flow and litter fall inside of the forest. In each site, we establish the 20 m x 20 m plot to monitor the changes of fallout radionuclides through time with the portable HPGe detector. The monitoring is now ongoing but we found significant amount of Cs-134 and Cs-137 has been trapped by cedar forest plantations especially young trees, but not so much in broad leaf trees. The trapped Cs-137 and Cs-134 is then washed by rainfall and found into throughfall. Therefore, in forest ecosystems, the fallout has been still ongoing, and and effective remediation method in forested area (especially cedar plantation) can be removing the trees.

  10. The Self-Shielding of Fallout Gamma Rays by Terrain Roughness

    DTIC Science & Technology

    1991-02-28

    Monte C, ORNL/TM-9355, Oak Ridge National Laboratory, Oak Ridge, TN, 1985. 98 7. Emmett, M. B., General Purpose Monte Carlo Multigroup Neutron and Gamma...I 28 FEBRUARY 1991 Di~t 3; or A v o p Approved for public release; distribution unlimited .- - i. ... .. F...model the fallout gamma source distribution , it will be modelled as an infinite plane source with gamma emission rates (GER) and gamma energy spectra as

  11. Synthetic fibers in atmospheric fallout: A source of microplastics in the environment?

    PubMed

    Dris, Rachid; Gasperi, Johnny; Saad, Mohamed; Mirande, Cécile; Tassin, Bruno

    2016-03-15

    Sources, pathways and reservoirs of microplastics, plastic particles smaller than 5mm, remain poorly documented in an urban context. While some studies pointed out wastewater treatment plants as a potential pathway of microplastics, none have focused on the atmospheric compartment. In this work, the atmospheric fallout of microplastics was investigated in two different urban and sub-urban sites. Microplastics were collected continuously with a stainless steel funnel. Samples were then filtered and observed with a stereomicroscope. Fibers accounted for almost all the microplastics collected. An atmospheric fallout between 2 and 355 particles/m(2)/day was highlighted. Registered fluxes were systematically higher at the urban than at the sub-urban site. Chemical characterization allowed to estimate at 29% the proportion of these fibers being all synthetic (made with petrochemicals), or a mixture of natural and synthetic material. Extrapolation using weight and volume estimates of the collected fibers, allowed a rough estimation showing that between 3 and 10 tons of fibers are deposited by atmospheric fallout at the scale of the Parisian agglomeration every year (2500 km(2)). These results could serve the scientific community working on the different sources of microplastic in both continental and marine environments.

  12. Ash fallout scenarios at Vesuvius: Numerical simulations and implications for hazard assessment

    NASA Astrophysics Data System (ADS)

    Macedonio, G.; Costa, A.; Folch, A.

    2008-12-01

    Volcanic ash fallout subsequent to a possible renewal of the Vesuvius activity represents a serious threat to the highly urbanized area around the volcano. In order to assess the relative hazard we consider three different possible scenarios such as those following Plinian, Sub-Plinian, and violent Strombolian eruptions. Reference eruptions for each scenario are similar to the 79 AD (Pompeii), the 1631 AD (or 472 AD) and the 1944 AD Vesuvius events, respectively. Fallout deposits for the first two scenarios are modeled using HAZMAP, a model based on a semi-analytical solution of the 2D advection-diffusion-sedimentation equation. In contrast, fallout following a violent Strombolian event is modeled by means of FALL3D, a numerical model based on the solution of the full 3D advection-diffusion-sedimentation equation which is valid also within the atmospheric boundary layer. Inputs for models are total erupted mass, eruption column height, bulk grain-size, bulk component distribution, and a statistical set of wind profiles obtained by the NCEP/NCAR re-analysis. We computed ground load probability maps for different ash loadings. In the case of a Sub-Plinian scenario, the most representative tephra loading maps in 16 cardinal directions were also calculated. The probability maps obtained for the different scenarios are aimed to give support to the risk mitigation strategies.

  13. Observations of fallout from the Fukushima reactor accident in Cienfuegos, Cuba.

    PubMed

    Alonso-Hernandez, Carlos M; Guillen-Arruebarrena, Aniel; Cartas-Aguila, Hector; Morera-Gomez, Yasser; Diaz-Asencio, Misael

    2012-05-01

    Following the recent accident at the Fukushima Daiichi nuclear power plant in Japan, radioactive contamination was observed near the reactor site. As a contribution towards the understanding of the worldwide impact of the accident, we collected fallout samples in Cienfuegos, Cuba, and examined them for the presence of above normal amounts of radioactivity. Gamma ray spectra measured from these samples showed clear evidence of fission products (131)I and (137)Cs. However, the fallout levels measured for these isotopes (135 ± 4.78 mBq m(-2) day(-1) for (131)I and 10.7 ± 0.38 mBq m(-2) day(-1)for (137)Cs) were very low and posed no health risk to the public. The doses received as consequence to the Fukushima fallout by the Cienfuegos population's (0.002 mSv per year) don't overcome the limit of dose (1 mSv per year) fixed for the public in Cuba.

  14. Development and validation of a new fallout transport method using variable spectral winds

    SciTech Connect

    Hopkins, A.T.

    1984-01-01

    A new method was developed to incorporate variable winds into fallout transport calculations. The method uses spectral coefficients derived by the National Meteorological Center. Wind vector components are computed with the coefficients along the trajectories of falling particles. Spectral winds are used in the two-step method to compute dose rate on the ground, downwind of a nuclear cloud. First, the hotline is located by computing trajectories of particles from an initial, stabilized cloud, through spectral winds to the ground. The connection of particle landing points is the hotline. Second, dose rate on and around the hotline is computed by analytically smearing the falling cloud's activity along the ground. The feasibility of using spectral winds for fallout particle transport was validated by computing Mount St. Helens ashfall locations and comparing calculations to fallout data. In addition, an ashfall equation was derived for computing volcanic ash mass/area on the ground. Ashfall data and the ashfall equation were used to back-calculate an aggregated particle size distribution for the Mount St. Helens eruption cloud.

  15. PROJECTED LIFETIME CANCER RISKS FROM EXPOSURE TO REGIONAL RADIOACTIVE FALLOUT IN THE MARSHALL ISLANDS

    PubMed Central

    Land, Charles E.; Bouville, Andre; Apostoaei, Iulian; Simon, Steven L.

    2013-01-01

    Radioactive fallout from nuclear test detonations during 1946–1958 at Bikini and Enewetak atolls in the Marshall Islands (MI) exposed populations living elsewhere in the archipelago. A comprehensive analysis, presented in seven companion papers, has produced estimates of tissue-specific radiation absorbed dose to MI residents at all historically inhabited atolls from internal (ingested) and external radioactive components of fallout, by calendar year, and by age of the population at time of exposure. The present report deals, for the first time, with the implications of these doses on cancer risk among exposed members of the MI population. Radiation doses differed by geographic location and year of birth, and radiation-related cancer risk depends upon age at exposure and age at observation for risk. Using dose-response models based on committee reports published by the National Research Council and the National Institutes of Health, we project that, during the lifetimes of members of the MI population potentially exposed to ionizing radiation from weapons test fallout deposited during the testing period (1948–1958) and from residual radioactive sources during the subsequent 12 years (1959–1970), perhaps 1.6% (with 90% uncertainty range 0.4% and 3.4%) of all cancers might be attributable to fallout-related radiation exposures. The projected proportion of cancers attributable to radiation from fallout from all nuclear tests conducted in the Marshall Islands is 55% (28%–69%) among 82 persons exposed in 1954 on Rongelap and Ailinginae, 10% (2%–22%) for 157 persons exposed on Utrik, and 2% (0.5%–5%) and 1% (0.2%–2%), respectively, for the much larger populations exposed in mid-latitude locations including Kwajalein and in southern locations including Majuro. By cancer type, point estimates of attributable risk varied by location, between 12% and 95% for thyroid cancer, between 2% and 78% for leukemia, and between 1% and 55% for all cancers combined. The

  16. Projected lifetime cancer risks from exposure to regional radioactive fallout in the Marshall Islands.

    PubMed

    Land, Charles E; Bouville, André; Apostoaei, Iulian; Simon, Steven L

    2010-08-01

    Radioactive fallout from nuclear test detonations during 1946-1958 at Bikini and Enewetak Atolls in the Marshall Islands (MI) exposed populations living elsewhere in the MI archipelago. A comprehensive analysis, presented in seven companion papers, has produced estimates of tissue-specific radiation absorbed dose to MI residents at all historically inhabited atolls from internal (ingested) and external irradiation resulting from exposure to radioactive fallout, by calendar year, and by age of the population at time of exposure. The present report deals, for the first time, with the implications of these doses for cancer risk among exposed members of the MI population. Radiation doses differed by geographic location and year of birth, and radiation-related cancer risk depends upon age at exposure and age at observation for risk. Using dose-response models based on committee reports published by the National Research Council and the National Institutes of Health, we project that, during the lifetimes of members of the MI population potentially exposed to ionizing radiation from weapons test fallout deposited during the testing period (1948-1958) and from residual radioactive sources during the subsequent 12 y (1959-1970), perhaps 1.6% (with 90% uncertainty range 0.4% to 3.4%) of all cancers might be attributable to fallout-related radiation exposures. By sub-population, the projected proportion of cancers attributable to radiation from fallout from all nuclear tests conducted in the Marshall Islands is 55% (28% to 69%) among 82 persons exposed in 1954 on Rongelap and Ailinginae, 10% (2.4% to 22%) for 157 persons exposed on Utrik, and 2.2% (0.5% to 4.8%) and 0.8% (0.2% to 1.8%), respectively, for the much larger populations exposed in mid-latitude locations including Kwajalein and in southern locations including Majuro. By cancer type, point estimates of attributable risk varied, by location, between 12% and 95% for thyroid cancer, between 2% and 78% for leukemia, and

  17. PREDICTIONS OF DISPERSION AND DEPOSITION OF FALLOUT FROM NUCLEAR TESTING USING THE NOAA-HYSPLIT METEOROLOGICAL MODEL

    PubMed Central

    Moroz, Brian E.; Beck, Harold L.; Bouville, André; Simon, Steven L.

    2013-01-01

    The NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was evaluated as a research tool to simulate the dispersion and deposition of radioactive fallout from nuclear tests. Model-based estimates of fallout can be valuable for use in the reconstruction of past exposures from nuclear testing, particularly, where little historical fallout monitoring data is available. The ability to make reliable predictions about fallout deposition could also have significant importance for nuclear events in the future. We evaluated the accuracy of the HYSPLIT-predicted geographic patterns of deposition by comparing those predictions against known deposition patterns following specific nuclear tests with an emphasis on nuclear weapons tests conducted in the Marshall Islands. We evaluated the ability of the computer code to quantitatively predict the proportion of fallout particles of specific sizes deposited at specific locations as well as their time of transport. In our simulations of fallout from past nuclear tests, historical meteorological data were used from a reanalysis conducted jointly by the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). We used a systematic approach in testing the HYSPLIT model by simulating the release of a range of particles sizes from a range of altitudes and evaluating the number and location of particles deposited. Our findings suggest that the quantity and quality of meteorological data are the most important factors for accurate fallout predictions and that when satisfactory meteorological input data are used, HYSPLIT can produce relatively accurate deposition patterns and fallout arrival times. Furthermore, when no other measurement data are available, HYSPLIT can be used to indicate whether or not fallout might have occurred at a given location and provide, at minimum, crude quantitative estimates of the magnitude of the deposited activity. A variety of

  18. Predictions of dispersion and deposition of fallout from nuclear testing using the NOAA-HYSPLIT meteorological model.

    PubMed

    Moroz, Brian E; Beck, Harold L; Bouville, André; Simon, Steven L

    2010-08-01

    The NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was evaluated as a research tool to simulate the dispersion and deposition of radioactive fallout from nuclear tests. Model-based estimates of fallout can be valuable for use in the reconstruction of past exposures from nuclear testing, particularly where little historical fallout monitoring data are available. The ability to make reliable predictions about fallout deposition could also have significant importance for nuclear events in the future. We evaluated the accuracy of the HYSPLIT-predicted geographic patterns of deposition by comparing those predictions against known deposition patterns following specific nuclear tests with an emphasis on nuclear weapons tests conducted in the Marshall Islands. We evaluated the ability of the computer code to quantitatively predict the proportion of fallout particles of specific sizes deposited at specific locations as well as their time of transport. In our simulations of fallout from past nuclear tests, historical meteorological data were used from a reanalysis conducted jointly by the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). We used a systematic approach in testing the HYSPLIT model by simulating the release of a range of particle sizes from a range of altitudes and evaluating the number and location of particles deposited. Our findings suggest that the quantity and quality of meteorological data are the most important factors for accurate fallout predictions and that, when satisfactory meteorological input data are used, HYSPLIT can produce relatively accurate deposition patterns and fallout arrival times. Furthermore, when no other measurement data are available, HYSPLIT can be used to indicate whether or not fallout might have occurred at a given location and provide, at minimum, crude quantitative estimates of the magnitude of the deposited activity. A variety of

  19. Long-Term Consequences of Radioactive Fallout From Conflicts Involving Nuclear Explosions

    NASA Astrophysics Data System (ADS)

    Simon, S. L.; Bouville, A.

    2006-12-01

    This presentation will summarize past exposures of the public to radioactive fallout from nuclear testing and extrapolate to the possible fallout-related consequences from detonation of multiple warheads that might accompany international conflicts. Long-term consequences could be of three distinct types: (1) the abandonment of living areas that might be heavily contaminated; (2) the necessity to curtail use of particular agricultural products and foods, and (3) life-shortening due to increased rates of cancer and possibly some non-cancer diseases among the exposed populations. While the actual health and economic impact on the surviving public after such conflicts could vary tremendously depending on the number and sizes of explosions (fission yields), height of detonations, and the public's proximity to explosion sites, it is clear that multiple detonations would disperse radioactive products over large geographic areas. Our understanding of radioactive fallout is based on studies carried out for more than five decades on weapons testing fallout that originated from sites worldwide including Nevada, the Soviet Union, four locations in the Pacific, and elsewhere. Those studies have led to an understanding of the composition of radioactive fallout, of its radioactive qualities, and of its capacity to contaminate ground and agricultural products, as well as dwellings and workplaces located from a few km to tens of thousands of km from the explosion site. Though the most severe individual health consequences from exposure to fallout would most likely develop relatively close to the detonation sites (within a few hundred km), wide geographic distribution of fallout, well beyond the borders of the nations involved in the conflict, would affect much larger populations and would likely cause elevated cancer rates and cancer-related deaths among them for many decades following. While acute radiation symptoms (and even death) can result from very high short-term exposures

  20. A Screening Study of Thyroid Cancer and Other Thyroid Diseases among Individuals Exposed in Utero to Iodine-131 from Chernobyl Fallout

    PubMed Central

    Hatch, M.; Brenner, A.; Bogdanova, T.; Derevyanko, A.; Kuptsova, N.; Likhtarev, I.; Bouville, A.; Tereshchenko, V.; Kovgan, L.; Shpak, V.; Ostroumova, E.; Greenebaum, E.; Zablotska, L.; Ron, E.; Tronko, M.

    2009-01-01

    Background: Like stable iodine, radioiodines concentrate in the thyroid gland, increasing thyroid cancer risk in exposed children. Data on exposure to the embryonic/fetal thyroid are rare, raising questions about use of iodine 131 (I-131) in pregnant women. We present here estimated risks of thyroid disease from exposure in utero to I-131 fallout from the Chernobyl nuclear accident. Methods: We conducted a cross-sectional thyroid screening study (palpation, ultrasound, thyroid hormones, and, if indicated, fine needle aspiration) from 2003 to 2006. Participants were 2582 mother-child pairs from Ukraine in which the mother had been pregnant at the time of the accident on April 26, 1986, or 2 months after the time during which I-131 fallout was still present (1494 from contaminated areas, 1088 in the comparison group). Individual cumulative in utero thyroid dose estimates were derived from estimated I-131 activity in the mother’s thyroid (mean 72 mGy; range 0–3230 mGy). Results: There were seven cases of thyroid carcinoma and one case of Hurthle cell neoplasm identified as a result of the screening. Whereas the estimated excess odds ratio per gray for thyroid carcinoma was elevated (excess odds ratio per gray 11.66), it was not statistically significant (P = 0.12). No radiation risks were identified for other thyroid diseases. Conclusion: Our results suggest that in utero exposure to radioiodines may have increased the risk of thyroid carcinoma approximately 20 yr after the Chernobyl accident, supporting a conservative approach to medical uses of I-131 during pregnancy. PMID:19106267

  1. Radiation measurements in the Chiba Metropolitan Area and radiological aspects of fallout from the Fukushima Dai-ichi Nuclear Power Plants accident.

    PubMed

    Amano, Hikaru; Akiyama, Masakazu; Chunlei, Bi; Kawamura, Takao; Kishimoto, Takeshi; Kuroda, Tomotaka; Muroi, Takahiko; Odaira, Tomoaki; Ohta, Yuji; Takeda, Kenji; Watanabe, Yushu; Morimoto, Takao

    2012-09-01

    Large amounts of radioactive substances were released into the environment from the Fukushima Dai-ichi Nuclear Power Plants in eastern Japan as a consequence of the great earthquake (M 9.0) and tsunami of 11 March 2011. Radioactive substances discharged into the atmosphere first reached the Chiba Metropolitan Area on 15 March. We collected daily samples of air, fallout deposition, and tap water starting directly after the incident and measured their radioactivity. During the first two months maximum daily concentrations of airborne radionuclides observed at the Japan Chemical Analysis Center in the Chiba Metropolitan Area were as follows: 4.7 × 10(1) Bq m(-3) of (131)I, 7.5 Bq m(-3) of (137)Cs, and 6.1 Bq m(-3) of (134)Cs. The ratio of gaseous iodine to total iodine ranged from 5.2 × 10(-1) to 7.1 × 10(-1). Observed deposition rate maxima were as follows: 1.7 × 10(4) Bq m(-2) d(-1) of (131)I, 2.9 × 10(3) Bq m(-2) d(-1) of (137)Cs, and 2.9 × 10(3) Bq m(-2) d(-1) of (134)Cs. The deposition velocities (ratio of deposition rate to concentration) of cesium radionuclides and (131)I were detectably different. Radioactivity in tap water caused by the accident was detected several days after detection of radioactivity in fallout in the area. Radiation doses were estimated from external radiation and internal radiation by inhalation and ingestion of tap water for people living outdoor in the Chiba Metropolitan Area following the Fukushima accident.

  2. Can atom-surface potential measurements test atomic structure models?

    PubMed

    Lonij, Vincent P A; Klauss, Catherine E; Holmgren, William F; Cronin, Alexander D

    2011-06-30

    van der Waals (vdW) atom-surface potentials can be excellent benchmarks for atomic structure calculations. This is especially true if measurements are made with two different types of atoms interacting with the same surface sample. Here we show theoretically how ratios of vdW potential strengths (e.g., C₃(K)/C₃(Na)) depend sensitively on the properties of each atom, yet these ratios are relatively insensitive to properties of the surface. We discuss how C₃ ratios depend on atomic core electrons by using a two-oscillator model to represent the contribution from atomic valence electrons and core electrons separately. We explain why certain pairs of atoms are preferable to study for future experimental tests of atomic structure calculations. A well chosen pair of atoms (e.g., K and Na) will have a C₃ ratio that is insensitive to the permittivity of the surface, whereas a poorly chosen pair (e.g., K and He) will have a ratio of C₃ values that depends more strongly on the permittivity of the surface.

  3. Community health risk assessment after a fire with asbestos containing fallout

    PubMed Central

    Bridgman, S

    2001-01-01

    BACKGROUND—A factory fire in Tranmere, Merseyside, England, deposited asbestos containing fallout in an urban area. There was considerable community anxiety for months after the incident. Therefore an assessment of the long term health risks of this acute environmental incident were requested by the local health authority.
METHODS—The facts of the incident were gathered and appraised from unpublished and press reports, involved personnel, and further analysis of material collected at the time of the incident. The literature on the long term health risks of asbestos was reviewed, and combined with evidence on asbestos exposure to estimate community health risk.
RESULTS—Risk was almost entirely from exposure to fire fallout of chrysotile in asbestos bitumen paper covering the factory roof. Amosite was only detected in a few samples and in trace amounts. The number of people who lived in the area of fallout was 16 000 to 48 000. From a non-threshold model with assumptions likely to overestimate risk, the lung cancer risk is estimated to be undetectably small. Risk of mesothelioma from chrysotile exposure, and risks of lung cancer and mesothelioma from amosite exposure were based on observational studies and were estimated to be even lower than that of lung cancer risk from chrysotile exposure. Academically, there are assumptions that while reasonable cannot be proven, for example, the validity of extrapolating observed risk from much higher exposures to lower exposures, estimates of individual exposure, and that there is no threshold for asbestos to cause cancer.
CONCLUSIONS—The author is unaware of a similar study on long term health risks in a community exposed to asbestos in a fire. It is concluded that, using methods that do not underestimate risk, risk is undetectably small. Practical lessons from this methodology and approach to health risk assessment are discussed.


Keywords: asbestos; environmental pollutants; mesothelioma; health risk

  4. Estimation of the Adriatic Sea water turnover time using fallout 90Sr as a radioactive tracer

    NASA Astrophysics Data System (ADS)

    Franić, Zdenko

    2005-08-01

    Systematic, long-term measurements, starting in 1963, of 90Sr activity concentrations in sea water have been performed at four locations (cities of Rovinj, Rijeka, Split and Dubrovnik) along the Croatian coast of the Adriatic Sea. In addition, fallout samples were collected in the city of Zadar. 90Sr activity concentrations are in good correlation with the fallout activity, the coefficient of correlation being 0.72. After the nuclear moratorium on atmospheric nuclear bomb tests in 1960s, 90Sr activity concentrations in sea water exponentially dropped from 14.8 ± 2.4 Bq m -3 in 1963 to 2.0 ± 0.3 Bq m -3 in 2003. In the same period, the total annual 90Sr land surface deposit in Zadar fell by three orders of magnitude, from 713.3 Bq m -2 in 1963 to 0.4 Bq m -2 in 2003. Using strontium sea water and fallout data, a mathematical model was developed to describe the rate of change of 90Sr activity concentrations in the Adriatic Sea water and estimate its mean residence time in the Adriatic. By fitting the experimental data to a theoretically predicted curve, the mean residence time of 90Sr in the Adriatic Sea water was estimated to be approximately 3.4 ± 0.4 years, standard deviation being calculated by Monte Carlo simulations. As in physical oceanography 90Sr can be used as effective radioactive tracer of water mass transport, this value also reflects the upper limit for turnover time of the Adriatic Sea water. The turnover time of 3.4 years for the Adriatic Sea water is in reasonable agreement with the value which was estimated, by studying water flows through the Strait of Otranto, to be on the order of 1 year.

  5. Unexpected hazards from tephra fallouts at Mt Etna: The 23 November 2013 lava fountain

    NASA Astrophysics Data System (ADS)

    Andronico, Daniele; Scollo, Simona; Cristaldi, Antonio

    2015-10-01

    Hundreds of paroxysmal episodes and a few long-lasting ash-emissions eruptions make Mt. Etna, in Italy, one of the most productive basaltic volcanoes in the world over recent years. This frequent explosive activity certainly gives volcanologists plenty of stimulating scientific material for study. Volcanic hazard from tephra fallout associated with lava fountains is still an issue that has not been fully assessed, albeit having to face this scenario several times in 2013. The 23 November 2013 lava fountain was exceptionally intense despite the short duration of the paroxysmal phase (< 1 h). Abundant decimetric-sized bombs fell within the first 5-6 km from the vent, and a macroscopically thicker and coarser tephra deposit than usual formed between 5 and 25 km; in addition, ash was reported to fall up to distances of 400 km. The analysis of fallout deposit provided a total erupted mass of 1.3 ± 1.1 × 109 kg (for a mass eruption rate of 4.5 ± 3.6 × 105 kg/s), in agreement with the value of 2.4 × 109 kg estimated by modeling. Grain-size distribution of samples shows poor sorting at least up to 25 km from the vent. By comparing dispersal, sedimentological features and physical parameters of the fallout deposit with other lava fountains of Etna, the 23 November 2013 episode may well be one of the largest events of the 21st Century in terms of eruption column height, total erupted mass and mass eruption rate. Furthermore, the impact of tephra on the territory was so high as to make it opportune to introduce a distinction, within the class of lava fountains, between small- and large-scale episodes. This classification can be a starting point for hazard assessment and help prevent the hazards from large-scale lava fountains at Etna in the future.

  6. First measurements of (236)U concentrations and (236)U/(239)Pu isotopic ratios in a Southern Hemisphere soil far from nuclear test or reactor sites.

    PubMed

    Srncik, M; Tims, S G; De Cesare, M; Fifield, L K

    2014-06-01

    The variation of the (236)U and (239)Pu concentrations as a function of depth has been studied in a soil profile at a site in the Southern Hemisphere well removed from nuclear weapon test sites. Total inventories of (236)U and (239)Pu as well as the (236)U/(239)Pu isotopic ratio were derived. For this investigation a soil core from an undisturbed forest area in the Herbert River catchment (17°30' - 19°S) which is located in north-eastern Queensland (Australia) was chosen. The chemical separation of U and Pu was carried out with a double column which has the advantage of the extraction of both elements from a relatively large soil sample (∼20 g) within a day. The samples were measured by Accelerator Mass Spectrometry using the 14UD pelletron accelerator at the Australian National University. The highest atom concentrations of both (236)U and (239)Pu were found at a depth of 2-3 cm. The (236)U/(239)Pu isotopic ratio in fallout at this site, as deduced from the ratio of the (236)U and (239)Pu inventories, is 0.085 ± 0.003 which is clearly lower than the Northern Hemisphere value of ∼0.2. The (236)U inventory of (8.4 ± 0.3) × 10(11) at/m(2) was more than an order of magnitude lower than values reported for the Northern Hemisphere. The (239)Pu activity concentrations are in excellent agreement with a previous study and the (239+240)Pu inventory was (13.85 ± 0.29) Bq/m(2). The weighted mean (240)Pu/(239)Pu isotopic ratio of 0.142 ± 0.005 is slightly lower than the value for global fallout, but our results are consistent with the average ratio of 0.173 ± 0.027 for the southern equatorial region (0-30°S).

  7. Analysis of Aerosols and Fallout from High-Explosive Dust Clouds. Volume 2

    DTIC Science & Technology

    1977-03-01

    between the wet cyclone and the airborne filter sampler , a summary of environmental impact data collected in the Mixed Company III cloud, a description of...through a narrow slit from the 3 in. tube during each pass and impacted on the tape as patches measuring AI-4 about one square centimeter. The inlet... Samplers AIX-5 C. Deployment AIX-5 1. Close Grid AIX-6 2. Extended Grid AIX-7 D. Operating Procedure AIX-8 1. Fallout Trays AIX-8 2. Impact Trays AIX-8 3

  8. Toxoplasma antibodies and retinochoroiditis in the Marshall Islands and their association with exposure to radioactive fallout

    SciTech Connect

    Adams, W.H.; Kindermann, W.R.; Walls, K.W.; Heotis, P.M.

    1987-03-01

    Nearly universal serologic evidence of Toxoplasma gondii infection was found to have occurred by adulthood in 517 Marshallese tested in 1981-1982. The prevalence and incidence of retinal lesions compatible with toxoplasmosis were 3.9% and 273 cases/year/100,000 seropositive persons, respectively, thus indicating a significant public health problem. Seronegativity was significantly more common in a subgroup of Marshallese that had received 110-190 rads of total-body gamma radiation as a consequence of accidental exposure to radioactive fallout in 1954. Despite this finding there was no evidence of an increase in clinically significant lesions in exposed persons.

  9. Transfer of 137Cs from Chernobyl debris and nuclear weapons fallout to different Swedish population groups.

    PubMed

    Rääf, C L; Hubbard, L; Falk, R; Agren, G; Vesanen, R

    2006-08-15

    Data from measurements on the body burden of (134)Cs, (137)Cs and (40)K in various Swedish populations between 1959 and 2001 has been compiled into a national database. The compilation is a co-operation between the Departments of Radiation Physics in Malmö and Göteborg, the National Radiation Protection Authority (SSI) and the Swedish Defense Research Agency (FOI). In a previous study the effective ecological half time and the associated effective dose to various Swedish populations due to internal contamination of (134)Cs and (137)Cs have been assessed using the database. In this study values of human body burden have been combined with data on the local and regional ground deposition of fallout from nuclear weapons tests (only (137)Cs) and Chernobyl debris (both (134)Cs and (137)Cs), which have enabled estimates of the radioecological transfer in the studied populations. The assessment of the database shows that the transfer of radiocesium from Chernobyl fallout to humans varies considerably between various populations in Sweden. In terms of committed effective dose over a 70 y period from internal contamination per unit activity deposition, the general (predominantly urban) Swedish population obtains 20-30 microSv/kBq m(-2). Four categories of populations exhibit higher radioecological transfer than the general population; i.) reindeer herders ( approximately 700 microSv/kBq m(-2)), ii.) hunters in the counties dominated by forest vegetation ( approximately 100 microSv/kBq m(-2)), iii.) rural non-farming populations living in sub-arctic areas (40-150 microSv/kBq m(-2)), and iv.) farmers ( approximately 50 microSv/kBq m(-2)). Two important factors determine the aggregate transfer from ground deposition to man; i.) dietary habits (intakes of foodstuff originating from natural and semi-natural ecosystems), and ii.) inclination to follow the recommended food restriction by the authorities. The transfer to the general population is considerably lower

  10. Source apportionment of mercury in dust fallout at urban residential area of Central India

    NASA Astrophysics Data System (ADS)

    Pervez, S.; Balakrishna, G.; Tiwari, S.

    2009-10-01

    The components and quantities of atmospheric dust fallout have been reported to be the pollution indicator of large urban areas. The multiplicity and complexity of sources of atmospheric dusts in urban regions (e.g. industrial complexes composed of a variety of industrial processes, automobiles, construction activities etc.) has put forward the need of source apportionment of these sources indicating their contribution to specific environmental receptor. The study presented here is focused on investigation of source contribution estimates of Mercury in urban dust fallout in an urban-industrial area, Raipur, India. Source-receptor based representative sampling plan using longitudinal study design has been adopted. Six sampling sites have been identified on the basis of land use for development plan of anthropogenic activities and factors related to the transportation and dispersion pattern of atmospheric dusts. 24 samples of dust fallout has been collected from each site (one in each month) and subjected to chemical analysis of selected chemical constituents known as markers of selected major dust emitting sources (Steel making average, Road traffic-borne dusts, construction activities, Auto mobile exhaust, and soils). Chemical composition of dust measured at sites marked for identified sources alongwith SPECIATE of USEPA has been used for the preparation of source profiles. Three classified residential receptors (ambient-outdoor, house-indoors and local street-outdoors) have been chosen for development of receptor compositional profiles. Source apportionment has been done using Chemical Mass Balance (CMB 8). Good fit parameters and relative source contribution has been analysed and documented. Dust fallout and respective mercury levels were found tobe higher compared to prescribed standards. Variation in relative contribution of selected sources from site to site within the study area has been occurred. Dominance of local line and area sources (road-traffic and

  11. Rapid determination of ¹³⁵Cs and precise ¹³⁵Cs/¹³⁷Cs atomic ratio in environmental samples by single-column chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry.

    PubMed

    Yang, Guosheng; Tazoe, Hirofumi; Yamada, Masatoshi

    2016-02-18

    For source identification, measurement of (135)Cs/(137)Cs atomic ratio not only provides information apart from the detection of (134)Cs and (137)Cs, but it can also overcome the application limit that measurement of the (134)Cs/(137)Cs ratio has due to the short half-life of (134)Cs (2.06 y). With the recent advancement of ICP-MS, it is necessary to improve the corresponding separation method for rapid and precise (135)Cs/(137)Cs atomic ratio analysis. A novel separation and purification technique was developed for the new generation of triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS). The simple chemical separation, incorporating ammonium molybdophosphate selective adsorption of Cs and subsequent single cation-exchange chromatography, removes the majority of isobaric and polyatomic interference elements. Subsequently, the ICP-MS/MS removes residual interference elements and eliminates the peak tailing effect of stable (133)Cs, at m/z 134, 135, and 137. The developed analytical method was successfully applied to measure (135)Cs/(137)Cs atomic ratios and (135)Cs activities in environmental samples (soil and sediment) for radiocesium source identification.

  12. Atomic Oxygen Textured Polymers

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Hunt, Jason D.; Drobotij, Erin; Cales, Michael R.; Cantrell, Gidget

    1995-01-01

    Atomic oxygen can be used to microscopically alter the surface morphology of polymeric materials in space or in ground laboratory facilities. For polymeric materials whose sole oxidation products are volatile species, directed atomic oxygen reactions produce surfaces of microscopic cones. However, isotropic atomic oxygen exposure results in polymer surfaces covered with lower aspect ratio sharp-edged craters. Isotropic atomic oxygen plasma exposure of polymers typically causes a significant decrease in water contact angle as well as altered coefficient of static friction. Such surface alterations may be of benefit for industrial and biomedical applications. The results of atomic oxygen plasma exposure of thirty-three (33) different polymers are presented, including typical morphology changes, effects on water contact angle, and coefficient of static friction.

  13. Relationships between soil properties and contents in trace elements in a landscape impacted by atmospheric fallouts in Belgium

    NASA Astrophysics Data System (ADS)

    Liénard, Amandine; Colinet, Gilles

    2013-04-01

    Examples of sites contaminated by atmospheric fallouts are numerous across former industrial areas, among which the valleys of Sambre and Meuse in Wallonia hosted metal ore treatment factories. Trace contaminants that fell on soil surface can migrate in the landscape under soluble or particle forms through various processes such as erosion, lixiviation, biological transportation, aso. We first investigated the spatial distribution of some metallic trace elements in soils around a former zinc-ore treatment plant to a distance of 3km. In a second stage, we studied the relationships between trace contents and soil properties, in order to evaluate the risks of mobility. The sampling strategy aimed at (i) verifying that the main source of trace elements was the plant chimney, (ii) assessing the impact of the wind directions on fallout dispersion and (iii) evaluating whether there were differences of contents according to soil types and to soil occupation. Two hundred and fifty topsoil samples were collected according to a stratified design dealing with distance to the chimney, direction of dominant winds, soil type (loamy soil with good drainage, loamy soil with poor drainage and loamy-stony soils with gravels), and land use (crop, grassland and forest). Pseudo-total and available contents in trace and major elements, pH, TOC, and N were determined in the laboratory. Besides classical statistical analysis, (i) correlations between different parameters of soil, (ii) ANOVA (two or three way), (iii) ANCOVA (three-way ANOVA with the distance as a co-variate), (iv) regressions and (v) Principal Component Analysis were also performed. First results show that (i) contaminants (Cd, Pb, Zn and Cu) contents are closely correlated to each other and (ii) Cd, Pb and Zn are negatively correlated with the distance (R2 > 0.5; p-value < 0.001). So, the geographical location explained by the "distance" factor is the main driving factor of trace elements contents in soils. Moreover, the

  14. Fluoride distribution and biological availability in the fallout from mount st. Helens, 18 to 21 may 1980.

    PubMed

    Taves, D R

    1980-12-19

    Concentrations of fluoride in the ash fallout in central Washington from the 18 May 1980 eruption of Mount St. Helens varied severalfold, but none are high enough to constitute any immediate hazard to animal life. The heaviest fallout (Moses Lake) contained 113 parts per million (ppm) of acid-labile fluoride, but of this only 11 ppm was water-soluble and 20 ppm was available to rats. The fluoride concentrations in the urine of cattle feeding for 4 days on hay contaminated with this ash were essentially normal. Samples of ash from other areas generally had higher concentrations of acid-labile fluoride but lower concentrations of water-soluble fluoride. The concentration of water-soluble fluoride was inversely correlated with the coarseness of the fallout.

  15. Fluoride distribution and biological availability in the fallout from Mount St. Helens, 18 to 21 May 1980

    SciTech Connect

    Taves, D.R.

    1980-12-19

    Concentrations of fluoride in the ash fallout in central Washington from the 18 May 1980 eruption of Mount St. Helens varied severalfold, but none are high enough to constitute any immediate hazard to animal life. The heaviest fallout (Moses Lake) contained 113 parts per million (ppm) of acid-labile fluoride, but of this only 11 ppm was water-soluble and 20 ppm was available to rats. The fluoride concentrations in the urine of cattle feeding for 4 days on hay contaminated with this ash were essentially normal. Samples of ash from other areas generally had higher concentrations of acid-labile fluoride but lower concentrations of water-soluble fluoride. The concentrations of water-soluble fluoride was inversely correlated with the coarseness of the fallout. 8 references, 1 figure, 1 table.

  16. Use of plutonium isotope activity ratios in dating recent sediments. [/sup 238/Pu//sup 239/Pu + /sup 240/Pu

    SciTech Connect

    Beasley, T. M.

    1982-01-01

    The majority of plutonium presently in the biosphere has come from the testing of nuclear devices. In the early 1950s, the Pu-238/239+240 activity ratio of fallout debris was > 0.04; in the more extensive test series of 1961 to 1962, the Pu-238/239+240 activity ratios were quite consistent at 0.02 to 0.03 and maximum fallout delivery occurred in mid-1963. A significant perturbation in Pu isotope activity ratios occurred in mid-1966 with the deposition of Pu-238 from the SNAP-9A reentry and burn-up. Recently deposited sediments have recorded these events and where accumulation rates are rapid (> 1 cm/y), changes in Pu isotope activity ratios can be used as a geochronological tool.

  17. Measurement of (233)U/(234)U ratios in contaminated groundwater using alpha spectrometry.

    PubMed

    Harrison, Jennifer J; Payne, Timothy E; Wilsher, Kerry L; Thiruvoth, Sangeeth; Child, David P; Johansen, Mathew P; Hotchkis, Michael A C

    2016-01-01

    The uranium isotope (233)U is not usually observed in alpha spectra from environmental samples due to its low natural and fallout abundance. It may be present in samples from sites in the vicinity of nuclear operations such as reactors or fuel reprocessing facilities, radioactive waste disposal sites or sites affected by clandestine nuclear operations. On an alpha spectrum, the two most abundant alpha emissions of (233)U (4.784 MeV, 13.2%; and 4.824 MeV, 84.3%) will overlap with the (234)U doublet peak (4.722 MeV, 28.4%; and 4.775 MeV, 71.4%), if present, resulting in a combined (233+234)U multiplet. A technique for quantifying both (233)U and (234)U from alpha spectra was investigated. A series of groundwater samples were measured both by accelerator mass spectrometry (AMS) to determine (233)U/(234)U atom and activity ratios and by alpha spectrometry in order to establish a reliable (233)U estimation technique using alpha spectra. The Genie™ 2000 Alpha Analysis and Interactive Peak Fitting (IPF) software packages were used and it was found that IPF with identification of three peaks ((234)U minor, combined (234)U major and (233)U minor, and (233)U major) followed by interference correction on the combined peak and a weighted average activity calculation gave satisfactory agreement with the AMS data across the (233)U/(234)U activity ratio range (0.1-20) and (233)U activity range (2-300 mBq) investigated. Correlation between the AMS (233)U and alpha spectrometry (233)U was r(2) = 0.996 (n = 10).

  18. Designing Shelter in New Buildings. A Manual for Architects on the Preliminary Designing of Shielding from Fallout Gamma Radiation in Normally Functioning Spaces in New Buildings.

    ERIC Educational Resources Information Center

    Knott, Albert

    Analysis of radiation fallout prevention factors in new construction is presented with emphasis on architectural shielding principles. Numerous diagrams and charts illustrate--(1) radiation and fallout properties, (2) building protection principles, (3) details and planning suggestions, and (4) tabular data interpretation. A series of charts is…

  19. Fallout Protection in School Construction. Proceedings, Association of School Business Officials of the United States and Canada (49th, Denver, Colorado, November 3-8, 1963).

    ERIC Educational Resources Information Center

    Roembke, James E.

    Discussion of the effects of nuclear weapons and consequent radiation fallout precedes justification of the need for fallout shelters. Competition for the design of an elementary school with a population of 300-500 and an emergency population of 600-1000 is then described. Criteria and requirements are detailed. The winning entries illustrate…

  20. Chernobyl nuclear reactor accident fallout: measurement and consequences. (Latest citations from the NTIS data base). Published Search

    SciTech Connect

    Not Available

    1992-04-01

    The bibliography contains citations concerning the consequences of radioactive fallout from the Chernobyl nuclear reactor accident. Coverage includes transfrontier radioactive contamination, deposition of radioactive pollutants from the atmosphere, and radionuclide concentrations in ground-level air and soil contamination, and in vegetation and food. Monthly radioactive monitoring in different countries, possible health hazards caused by the radiation, and estimates of radiation doses to the population from the fallout are also discussed. (Contains a minimum of 209 citations and includes a subject term index and title list.)

  1. Surficial redistribution of fallout 131iodine in a small temperate catchment

    NASA Astrophysics Data System (ADS)

    Landis, Joshua D.; Hamm, Nathan T.; Renshaw, Carl E.; Dade, W. Brian; Magilligan, Francis J.; Gartner, John D.

    2012-03-01

    Isotopes of iodine play significant environmental roles, including a limiting micronutrient (127I), an acute radiotoxin (131I), and a geochemical tracer (129I). But the cycling of iodine through terrestrial ecosystems is poorly understood, due to its complex environmental chemistry and low natural abundance. To better understand iodine transport and fate in a terrestrial ecosystem, we traced fallout 131iodine throughout a small temperate catchment following contamination by the 11 March 2011 failure of the Fukushima Daiichi nuclear power facility. We find that radioiodine fallout is actively and efficiently scavenged by the soil system, where it is continuously focused to surface soils over a period of weeks following deposition. Mobilization of historic (pre-Fukushima) 137cesium observed concurrently in these soils suggests that the focusing of iodine to surface soils may be biologically mediated. Atmospherically deposited iodine is subsequently redistributed from the soil system via fluvial processes in a manner analogous to that of the particle-reactive tracer 7beryllium, a consequence of the radionuclides' shared sorption affinity for fine, particulate organic matter. These processes of surficial redistribution create iodine hotspots in the terrestrial environment where fine, particulate organic matter accumulates, and in this manner regulate the delivery of iodine nutrients and toxins alike from small catchments to larger river systems, lakes and estuaries.

  2. Surficial redistribution of fallout 131iodine in a small temperate catchment

    PubMed Central

    Landis, Joshua D.; Hamm, Nathan T.; Renshaw, Carl E.; Dade, W. Brian; Magilligan, Francis J.; Gartner, John D.

    2012-01-01

    Isotopes of iodine play significant environmental roles, including a limiting micronutrient (127I), an acute radiotoxin (131I), and a geochemical tracer (129I). But the cycling of iodine through terrestrial ecosystems is poorly understood, due to its complex environmental chemistry and low natural abundance. To better understand iodine transport and fate in a terrestrial ecosystem, we traced fallout 131iodine throughout a small temperate catchment following contamination by the 11 March 2011 failure of the Fukushima Daiichi nuclear power facility. We find that radioiodine fallout is actively and efficiently scavenged by the soil system, where it is continuously focused to surface soils over a period of weeks following deposition. Mobilization of historic (pre-Fukushima) 137cesium observed concurrently in these soils suggests that the focusing of iodine to surface soils may be biologically mediated. Atmospherically deposited iodine is subsequently redistributed from the soil system via fluvial processes in a manner analogous to that of the particle-reactive tracer 7beryllium, a consequence of the radionuclides’ shared sorption affinity for fine, particulate organic matter. These processes of surficial redistribution create iodine hotspots in the terrestrial environment where fine, particulate organic matter accumulates, and in this manner regulate the delivery of iodine nutrients and toxins alike from small catchments to larger river systems, lakes and estuaries. PMID:22378648

  3. Direct Pb Isotopic Analysis of a Nuclear Fallout Debris Particle from the Trinity Nuclear Test.

    PubMed

    Bellucci, Jeremy J; Snape, Joshua F; Whitehouse, Martin J; Nemchin, Alexander A

    2017-02-07

    The Pb isotope composition of a nuclear fallout debris particle has been directly measured in post-detonation materials produced during the Trinity nuclear test by a secondary ion mass spectrometry (SIMS) scanning ion image technique (SII). This technique permits the visual assessment of the spatial distribution of Pb and can be used to obtain full Pb isotope compositions in user-defined regions in a 70 μm × 70 μm analytical window. In conjunction with backscattered electron (BSE) and energy-dispersive spectroscopy (EDS) mapping of the same particle, the Pb measured in this fallout particle cannot be from a major phase in the precursor arkosic sand. Similarly, the Pb isotope composition of the particle is resolvable from the surrounding glass at the 2σ uncertainty level (where σ represents the standard deviation). The Pb isotope composition measured in the particle here is in excellent agreement with that inferred from measurements of green and red trinitite, suggesting that these types of particles are responsible for the Pb isotope compositions measured in both trinitite glasses.

  4. Early in situ measurement of radioactive fallout in Fukushima city due to Fukushima Daiichi nuclear accident.

    PubMed

    Takada, Masashi; Suzuki, Toshikazu

    2013-07-01

    Using a high-purity germanium detector, both indoor and outdoor radionuclides that had deposited 1.5 d after the radioactive fallout events in the city of Fukushima were experimentally measured. Eleven artificial ((131)I, (132)I, (134)Cs, (136)Cs, (137)Cs, (129)Te, (129m)Te, (131m)Te, (132)Te, (140)La and (99m)Tc) and 5 natural radionuclides were identified. Total air kerma rates were mainly due to (132)I, (134)Cs and (136)Cs from 4 to 6 µGy/h at a 7.5-cm height from the ground. Radioactive contamination on the ground was contributed by (132)I and (132)Te, from 330 to 420 Bq/cm(2). In a worst-case scenario, the maximum skin dose rates were estimated to be from 520 to 670 µGy/h. Effective dose rates were evaluated to be 10 to 15 µSv/h and reached 17.9 µSv/h at 4 a.m. on 16 March. In the effective dose rates, (132)I, (134)Cs and (132)Te were the main contributors. Our measurements are useful for estimating dose levels in the public in the city of Fukushima during the days after radioactive fallout contamination.

  5. Surficial redistribution of fallout ¹³¹iodine in a small temperate catchment.

    PubMed

    Landis, Joshua D; Hamm, Nathan T; Renshaw, Carl E; Dade, W Brian; Magilligan, Francis J; Gartner, John D

    2012-03-13

    Isotopes of iodine play significant environmental roles, including a limiting micronutrient ((127)I), an acute radiotoxin ((131)I), and a geochemical tracer ((129)I). But the cycling of iodine through terrestrial ecosystems is poorly understood, due to its complex environmental chemistry and low natural abundance. To better understand iodine transport and fate in a terrestrial ecosystem, we traced fallout (131)iodine throughout a small temperate catchment following contamination by the 11 March 2011 failure of the Fukushima Daiichi nuclear power facility. We find that radioiodine fallout is actively and efficiently scavenged by the soil system, where it is continuously focused to surface soils over a period of weeks following deposition. Mobilization of historic (pre-Fukushima) (137)cesium observed concurrently in these soils suggests that the focusing of iodine to surface soils may be biologically mediated. Atmospherically deposited iodine is subsequently redistributed from the soil system via fluvial processes in a manner analogous to that of the particle-reactive tracer (7)beryllium, a consequence of the radionuclides' shared sorption affinity for fine, particulate organic matter. These processes of surficial redistribution create iodine hotspots in the terrestrial environment where fine, particulate organic matter accumulates, and in this manner regulate the delivery of iodine nutrients and toxins alike from small catchments to larger river systems, lakes and estuaries.

  6. Medical status of Marshallese accidentally exposed to 1954 Bravo fallout radiation: January 1980-December 1982

    SciTech Connect

    Adams, W.H.; Harper, J.A.; Rittmaster, R.S.; Heotis, P.M.; Scott, W.A.

    1984-01-01

    This report updates, for 1980 through 1982, the results of continuing medical surveillance of a Marshallese population accidentally exposed to radioactive fallout in March 1954. The originally exposed Marshallese population comprised 64 persons on Rongelap Atoll who each received, on the average, an estimated 190 rads of absorbed external gamma radiation, 18 on Ailingnae Atoll who received 110 rads, and 159 on Utirik who received 11 rads. There were, in addition, 3 persons in utero on Rongelap, 1 person in utero on Ailingnae, and 8 persons in utero on Utirik who are considered exposed. The recipients of primary medical care include exposed and comparison populations as well as a rather large number of additional beneficiaries who are seen on a humanitarian basis of practical need and resource availability. In recent years, about 1400 people have been seen annually. This report, however, deals with four clearly defined groups: the remaining individuals who were exposed to radioactive fallout on Rongelap, Ailingnae, and Utirik in 1954 (including those in utero), and a comparison population of individuals from Rongelap who were unexposed. The number of persons now in each exposure category are 51, 12, 116, and 137, respectively. 100 references, 4 figures, 5 tables. (ACR)

  7. Meteoric smoke fallout over the Holocene epoch revealed by iridium and platinum in Greenland ice.

    PubMed

    Gabrielli, Paolo; Barbante, Carlo; Plane, John M C; Varga, Anita; Hong, Sungmin; Cozzi, Giulio; Gaspari, Vania; Planchon, Frédéric A M; Cairns, Warren; Ferrari, Christophe; Crutzen, Paul; Cescon, Paolo; Boutron, Claude F

    2004-12-23

    An iridium anomaly at the Cretaceous/Tertiary boundary layer has been attributed to an extraterrestrial body that struck the Earth some 65 million years ago. It has been suggested that, during this event, the carrier of iridium was probably a micrometre-sized silicate-enclosed aggregate or the nanophase material of the vaporized impactor. But the fate of platinum-group elements (such as iridium) that regularly enter the atmosphere via ablating meteoroids remains largely unknown. Here we report a record of iridium and platinum fluxes on a climatic-cycle timescale, back to 128,000 years ago, from a Greenland ice core. We find that unexpectedly constant fallout of extraterrestrial matter to Greenland occurred during the Holocene, whereas a greatly enhanced input of terrestrial iridium and platinum masked the cosmic flux in the dust-laden atmosphere of the last glacial age. We suggest that nanometre-sized meteoric smoke particles, formed from the recondensation of ablated meteoroids in the atmosphere at altitudes >70 kilometres, are transported into the winter polar vortices by the mesospheric meridional circulation and are preferentially deposited in the polar ice caps. This implies an average global fallout of 14 +/- 5 kilotons per year of meteoric smoke during the Holocene.

  8. Using isotopic ratios for discrimination of environmental anthropogenic radioactivity.

    PubMed

    Hayes, Robert B; Akbarzadeh, Mansour

    2014-10-01

    When air is pulled into the WIPP repository for ventilation purposes, this air is unfiltered and contains all the components of ubiquitous anthropogenic radionuclides from global nuclear fallout (including Cs and Pu isotopes). Although the NORM in aeolian sand and dust contribute to the gross alpha beta activity on effluent air filters, there remains a need to discriminate effluent TRU generated in the disposal process at WIPP from TRU being pulled into the repository with the unfiltered surface air. This is only evaluated using ratios of Cs and Pu activity found through radioassay of air filters taken from the mine effluent. By characterizing both the credible range of Cs/Pu ratios from the environment and those known to exist in the waste, a rigorous test criteria is attained. The use of HPGE to assay Cs in the intake dust plated out in the mine allowed a gross assay of total TRU radioactivity pulled into the mine over time from global fallout. Radiochemistry of samples from deposition in the mine's air intake shaft was also carried out. The use of net activity ratios at background levels is also shown to follow a Cauchy distribution in terms of their expected statistical distributions.

  9. A calibration of the production rate ratio P-21/P-26 by low energy secondry neutrons: Identification of Ne spallation components at the 10(exp 6) atoms/g level in terrestrial samples

    NASA Technical Reports Server (NTRS)

    Graf, TH.; Niedermann, S.; Marti, K.

    1993-01-01

    The spallation ratio (Ne-22/Ne-21)(sub c) from Si was determined as 1.243 plus or minus 0.022 in a terrestrial quartz sample. We carried out a calibration of the in-situ production rate ratio P-21/P-26 in quartz samples for which Be-10 and Al-26 production rates were previously measured. A ratio P-21/P-26 of 0.67 plus or minus 0.12 is obtained.

  10. Jarvis Fallout.

    ERIC Educational Resources Information Center

    McCuen, John T.; Hoffland, Ginger

    1978-01-01

    With the passage of Proposition 13, California's community colleges lost an estimated two-thirds of their local revenues. As the largest such system, the Los Angeles Community College District is preparing for the hardest impact. Retrenchment, loss of local control, and legal difficulties are problems it faces. (JMD)

  11. Atomic Scale Plasmonic Switch.

    PubMed

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2016-01-13

    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.

  12. Electron - Atom Bremsstrahlung

    NASA Astrophysics Data System (ADS)

    Kim, Longhuan

    In this work we study the features of bremsstrahlung radiation from neutral atoms and atoms in hot dense plasmas. Predictions for the distributions of electron-atom bremsstrahlung radiation for both the point Coulomb potential and screened potentials are obtained using a classical numerical method. The results agree with exact quantum mechanical partial wave results for low incident electron energies in both the point Coulomb and screened potentials. In the screened potential the asymmetry parameter of a spectrum is reduced from the Coulomb values. The difference increases with decreasing energy and begins to oscillate at very low energies. We also studied the scaling properties of bremsstrahlung spectra and energy losses. It is found that the ratio of the radiative energy loss for positrons to that for electrons obeys a simple scaling law, being expressible fairly accurately as a function only of the quantity T(,1)/Z('2). This scaling is exact in the case of the point Coulomb potential, both for classical bremsstrahlung and for the nonrelativistic dipole Sommerfeld formula. We also studied bremsstrahlung from atoms in hot dense plasmas, describing the atomic potentials by the temperature-and-density dependent Thomas - Fermi model. Gaunt factors are obtained with the relativistic partial wave method for atoms in plasmas of various densities and temperatures. Features of the bremsstrahlung from atoms in such environments are discussed. The dependence of predicted bremsstrahlung spectra on the choice of potential from various average atom potential models for strongly coupled plasmas are also studied. For the energy range and plasma densities were considered, the choice of potential model among the elaborate atomic potentials is less important than the choice of the method of calculation. The use of a detailed configuration accounting method for bremsstrahlung processes in dense plasmas is less important than for some other atomic processes. We justify the usefulness

  13. Atomic polarizabilities

    SciTech Connect

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  14. Chernobyl nuclear reactor accident fallout: Measurement and consequences. (Latest citations from the NTIS Bibliographic database). Published Search

    SciTech Connect

    1993-09-01

    The bibliography contains citations concerning the consequences of radioactive fallout from the Chernobyl nuclear reactor accident. Citations discuss radioactive monitoring, health hazards, and radiation dosimetry. Radiation contamination in the air, soil, vegetation, and food is examined. (Contains a minimum of 208 citations and includes a subject term index and title list.)

  15. Chernobyl nuclear reactor accident fallout: Measurement and consequences. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1995-02-01

    The bibliography contains citations concerning the consequences of radioactive fallout from the Chernobyl nuclear reactor accident. Citations discuss radioactive monitoring, health hazards, and radiation dosimetry. Radiation contamination in the air, soil, vegetation, and food is examined. (Contains a minimum of 247 citations and includes a subject term index and title list.)

  16. Chernobyl Nuclear Reactor accident fallout: Measurement and consequences. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1996-11-01

    The bibliography contains citations concerning the consequences of radioactive fallout from the Chernobyl nuclear reactor accident. Citations discuss radioactive monitoring, health hazards, and radiation dosimetry. Radiation contamination in the air, soil, vegetation, and food is examined. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  17. Chernobyl nuclear reactor accident fallout: Measurement and consequences. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1994-01-01

    The bibliography contains citations concerning the consequences of radioactive fallout from the Chernobyl nuclear reactor accident. Citations discuss radioactive monitoring, health hazards, and radiation dosimetry. Radiation contamination in the air, soil, vegetation, and food is examined. (Contains a minimum of 210 citations and includes a subject term index and title list.)

  18. Chernobyl nuclear reactor accident fallout: Measurement and consequences. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1996-01-01

    The bibliography contains citations concerning the consequences of radioactive fallout from the Chernobyl nuclear reactor accident. Citations discuss radioactive monitoring, health hazards, and radiation dosimetry. Radiation contamination in the air, soil, vegetation, and food is examined. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  19. Fallout volume and litter type affect (137)Cs concentration difference in litter between forest and stream environments.

    PubMed

    Sakai, Masaru; Gomi, Takashi; Negishi, Junjiro N

    2016-11-01

    It is important to understand the changes in the (137)Cs concentration in litter through leaching when considering that (137)Cs is transferred from basal food resources to animals in forested streams. We found that the difference of (137)Cs activity concentration in litter between forest and stream was associated with both litter type and (137)Cs fallout volume around Fukushima, Japan. The (137)Cs activity concentrations in the litter of evergreen conifers tended to be greater than those in the litter of broad-leaved deciduous trees because of the absence of deciduous leaves during the fallout period in March 2011. Moreover, (137)Cs activity concentrations in forest litter were greater with respect to the (137)Cs fallout volume. The (137)Cs activity concentrations in stream litter were much lower than those in forest litter when those in forest litter were higher. The (137)Cs leaching patterns indicated that the differences in (137)Cs activity concentration between forest and stream litter could change with changes in both fallout volume and litter type. Because litter is an important basal food resource in the food webs of both forests and streams, the (137)Cs concentration gradient reflects to possible (137)Cs transfer from lower to higher trophic animals. Our findings will improve our understanding of the spatial heterogeneity and variability of (137)Cs concentrations in animals resident to the contaminated landscape.

  20. Neogene Fallout Tuffs from the Yellowstone Hotspot in the Columbia Plateau Region, Oregon, Washington and Idaho, USA

    PubMed Central

    Nash, Barbara P.; Perkins, Michael E.

    2012-01-01

    Sedimentary sequences in the Columbia Plateau region of the Pacific Northwest ranging in age from 16–4 Ma contain fallout tuffs whose origins lie in volcanic centers of the Yellowstone hotspot in northwestern Nevada, eastern Oregon and the Snake River Plain in Idaho. Silicic volcanism began in the region contemporaneously with early eruptions of the Columbia River Basalt Group (CRBG), and the abundance of widespread fallout tuffs provides the opportunity to establish a tephrostratigrahic framework for the region. Sedimentary basins with volcaniclastic deposits also contain diverse assemblages of fauna and flora that were preserved during the Mid-Miocene Climatic Optimum, including Sucker Creek, Mascall, Latah, Virgin Valley and Trout Creek. Correlation of ashfall units establish that the lower Bully Creek Formation in eastern Oregon is contemporaneous with the Virgin Valley Formation, the Sucker Creek Formation, Oregon and Idaho, Trout Creek Formation, Oregon, and the Latah Formation in the Clearwater Embayment in Washington and Idaho. In addition, it can be established that the Trout Creek flora are younger than the Mascall and Latah flora. A tentative correlation of a fallout tuff from the Clarkia fossil beds, Idaho, with a pumice bed in the Bully Creek Formation places the remarkably well preserved Clarkia flora assemblage between the Mascall and Trout Creek flora. Large-volume supereruptions that originated between 11.8 and 10.1 Ma from the Bruneau-Jarbidge and Twin Falls volcanic centers of the Yellowstone hotspot in the central Snake River Plain deposited voluminous fallout tuffs in the Ellensberg Formation which forms sedimentary interbeds in the CRBG. These occurrences extend the known distribution of these fallout tuffs 500 km to the northwest of their source in the Snake River Plain. Heretofore, the distal products of these large eruptions had only been recognized to the east of their sources in the High Plains of Nebraska and Kansas. PMID:23071494

  1. Development of the town data base: Estimates of exposure rates and times of fallout arrival near the Nevada Test Site

    SciTech Connect

    Thompson, C.B.; McArthur, R.D.; Hutchinson, S.W.

    1994-09-01

    As part of the U.S. Department of Energy`s Off-Site Radiation Exposure Review Project, the time of fallout arrival and the H+12 exposure rate were estimated for populated locations in Arizona, California, Nevada, and Utah that were affected by fallout from one or more nuclear tests at the Nevada Test Site. Estimates of exposure rate were derived from measured values recorded before and after each test by fallout monitors in the field. The estimate for a given location was obtained by retrieving from a data base all measurements made in the vicinity, decay-correcting them to H+12, and calculating an average. Estimates were also derived from maps produced after most events that show isopleths of exposure rate and time of fallout arrival. Both sets of isopleths on these maps were digitized, and kriging was used to interpolate values at the nodes of a 10-km grid covering the pattern. The values at any location within the grid were then estimated from the values at the surrounding grid nodes. Estimates of dispersion (standard deviation) were also calculated. The Town Data Base contains the estimates for all combinations of location and nuclear event for which the estimated mean H+12 exposure rate was greater than three times background. A listing of the data base is included as an appendix. The information was used by other project task groups to estimate the radiation dose that off-site populations and individuals may have received as a result of exposure to fallout from Nevada nuclear tests.

  2. Neogene fallout tuffs from the Yellowstone hotspot in the Columbia Plateau region, Oregon, Washington and Idaho, USA.

    PubMed

    Nash, Barbara P; Perkins, Michael E

    2012-01-01

    Sedimentary sequences in the Columbia Plateau region of the Pacific Northwest ranging in age from 16-4 Ma contain fallout tuffs whose origins lie in volcanic centers of the Yellowstone hotspot in northwestern Nevada, eastern Oregon and the Snake River Plain in Idaho. Silicic volcanism began in the region contemporaneously with early eruptions of the Columbia River Basalt Group (CRBG), and the abundance of widespread fallout tuffs provides the opportunity to establish a tephrostratigrahic framework for the region. Sedimentary basins with volcaniclastic deposits also contain diverse assemblages of fauna and flora that were preserved during the Mid-Miocene Climatic Optimum, including Sucker Creek, Mascall, Latah, Virgin Valley and Trout Creek. Correlation of ashfall units establish that the lower Bully Creek Formation in eastern Oregon is contemporaneous with the Virgin Valley Formation, the Sucker Creek Formation, Oregon and Idaho, Trout Creek Formation, Oregon, and the Latah Formation in the Clearwater Embayment in Washington and Idaho. In addition, it can be established that the Trout Creek flora are younger than the Mascall and Latah flora. A tentative correlation of a fallout tuff from the Clarkia fossil beds, Idaho, with a pumice bed in the Bully Creek Formation places the remarkably well preserved Clarkia flora assemblage between the Mascall and Trout Creek flora. Large-volume supereruptions that originated between 11.8 and 10.1 Ma from the Bruneau-Jarbidge and Twin Falls volcanic centers of the Yellowstone hotspot in the central Snake River Plain deposited voluminous fallout tuffs in the Ellensberg Formation which forms sedimentary interbeds in the CRBG. These occurrences extend the known distribution of these fallout tuffs 500 km to the northwest of their source in the Snake River Plain. Heretofore, the distal products of these large eruptions had only been recognized to the east of their sources in the High Plains of Nebraska and Kansas.

  3. Comparative assessment of natural radioactivity in fallout samples from Patras and Megalopolis, Greece.

    PubMed

    Papaefthymiou, H; Kritidis, P; Anousis, J; Sarafidou, J

    2005-01-01

    Bulk deposition samples were collected simultaneously from two Greek cities, Patras and Megalopolis, with different emission sources of natural radioactivity, on a monthly basis, during a whole year. Gross beta-activity and 238U- and 232Th-activities were determined in a total of 95 samples of deposited dust. The results were statistically analyzed in order to determine the natural radioactivity levels and their variations in the above cities. No significant difference was found in deposited dust amount between the two cities, while the values of gross beta-, 238U- and 232Th-activities were about 3, 71 and 4 times higher in Megalopolis than in Patras, respectively. This was attributed to the operation of lignite power plants A and B in the vicinity of the city of Megalopolis, while natural radioactivity concentrations in Patras' fallout samples were of natural sources.

  4. Observation of dust particle growth and fallout in RF-excited silane discharges

    SciTech Connect

    Boehme, W. . Siemens Research Lab. Technical Univ. of Munich, Garching ); Koehler, W.E.; Roemheld, M.; Seeboeck, R.J. . Siemens Research Lab.); Veprek, S. . Inst. for Chemistry of Information Recording)

    1994-04-01

    Particles formed during plasma enhanced chemical vapor deposition of amorphous silicon thin films which fall to the film surface, either during or after the process, may have a severely deleterious effect on film properties. In order to understand the mechanisms of particle formation and fallout the authors have investigated the growth and dynamics of particles in RF discharges in pure silane. The diameter of particles formed within the first 20 s of the discharge was investigated by electron microscopy of substrates with fallen out particles. Furthermore the authors used a He-Ne laser in combination with a diode array camera to measure temporally and spatially resolved light scattering from particles and deduced their sinking speed after switching off the discharge. The results are compared to a theoretical model on the particle dynamics.

  5. The influence of forest shelterbelts on 137Cs fallout in Chernobyl affected areas (Tula region, Russia).

    NASA Astrophysics Data System (ADS)

    Ivanov, Maxim; Shamshurina, Eugeniya; Tatyana, Paramonova; Vladimir, Belyaev; Angelina, Gavruchenkova; Nikolai, Lugovoy; Konstantinov, Pavel

    2015-04-01

    The radioactive fallout after Chernobyl accident caused serious contamination by 137Cs along extensive area of East-European plain.Cs137 fall down on earth surface in two ways: gravitational - "dry" and rainfall - "wet" way. "Dry" fallout is a result of direct deposition of radionuclides from atmosphere with average speed of about 0.1-1 mm/sec. The fate of "dry fall"is far less than rainfall mechanism. Erupted water steam of reactor zone full of radioactive material enriched precipitation with 137Cs. Therefore, the derived spatial structure of contamination was under control of rainfall pattern in May-June 1986. On the areas affected by rainfall fallout was the Southern part of Tula region in Middle Russia. It got name as "Plava hot spot" by the town in the center of this area. Tula is a traditional rural region, the vast areas covered by chernozem soils are cultivated for centuries. During cultivation forest cover was reduced that urged growth of wind erosion and loss of soil fertility. Hence, in the middle of 20 the century large arrangements for creation of forest shelterbelts were conducted. High efficiency of shelterbelts made them a widely provided part of new human-transformed landscape. Usually shelterbelts are set as a regular network across main direction of winds in particular region. Such organization help to reduce speed of air steam in the lowest 20-30 m layer of atmosphere. In addition, shelterbelts are very good collectors of snow in winter time which increase total moisture of soil and its fertility. Represented investigation is conducted to find out any correlation between shelterbelts and fallout of radionuclides. If such correlation is significant, it has to be taken into account for further environmental surveys. Two shelterbelts on the interfluve positions were chosen for detailed examination. Both selected objects emerged before 1986 but have different width, floristic composition, orientation and type of construction. One of shelterbelts is

  6. Effect of ash fallout on water quality in western Montana. Final report

    SciTech Connect

    Juday, R.E.; Keller, E.J.

    1984-01-01

    Subsequent to the eruption of Mount St. Helens in 1980, a water-quality study was conducted on lakes and streams of the Clearwater drainage of Western Montana and several oligotrophic high mountain lakes in Idaho. Field studies indicated that the fallout, although containing appreciable amounts of water-soluble nutrients, had virtually no effect on productivity of oligotrophic lakes. Appreciable increases in algal productivity were noted in the mesotrophic study lakes in 1980, although they were no larger than might be expected from climatological changes or from local logging activity. Laboratory studies showed that, imitating natural conditions, appreciable amounts of nutrients could be extracted from the ash, and that the extracts increased algal productivity in incubated lake samples.

  7. Medical status of Marshallese accidentally exposed to 1954 Bravo fallout radiation, January 1983-December 1984

    SciTech Connect

    Adams, W.H.; Engle, J.R.; Harper, J.A.; Heotis, P.M.; Scott, W.A.

    1986-01-01

    March 1, 1984, was the 30th anniversary of the Bravo thermonuclear test that resulted in the accidental exposure of the populations of Rongelap and Utirik atolls to radioactive fallout. The chronicling of the medical events resulting from that exposure is continued in this report, which covers the period from January 1983 through December 1984. An updated listing of all relevant publications from the Medical Department Brookhaven National Laboratory, is presented in the Reference Section. Thirty years of observation continue to show no detectable increase in mortality in the exposed population as a result of that exposure. The survival curves of the high-exposure Rongelap group, the low-exposure Utirik population, and an unexposed group of Rongelap people matched by age and sex to the exposed Rongelap group in 1957 continue to be similar. 89 refs., 2 figs., 6 tabs.

  8. Rainfall erosivity in catchments contaminated with fallout from the Fukushima Daiichi nuclear power plant accident

    NASA Astrophysics Data System (ADS)

    Laceby, J. Patrick; Chartin, Caroline; Evrard, Olivier; Onda, Yuichi; Garcia-Sanchez, Laurent; Cerdan, Olivier

    2016-06-01

    The Fukushima Daiichi nuclear power plant (FDNPP) accident in March 2011 resulted in the fallout of significant quantities of radiocesium over the Fukushima region. After reaching the soil surface, radiocesium is quickly bound to fine soil particles. Thereafter, rainfall and snowmelt run-off events transfer particle-bound radiocesium downstream. Characterizing the precipitation regime of the fallout-impacted region is thus important for understanding post-deposition radiocesium dynamics. Accordingly, 10 min (1995-2015) and daily precipitation data (1977-2015) from 42 meteorological stations within a 100 km radius of the FDNPP were analyzed. Monthly rainfall erosivity maps were developed to depict the spatial heterogeneity of rainfall erosivity for catchments entirely contained within this radius. The mean average precipitation in the region surrounding the FDNPP is 1420 mm yr-1 (SD 235) with a mean rainfall erosivity of 3696 MJ mm ha-1 h-1 yr-1 (SD 1327). Tropical cyclones contribute 22 % of the precipitation (422 mm yr-1) and 40 % of the rainfall erosivity (1462 MJ mm ha-1 h-1 yr-1 (SD 637)). The majority of precipitation (60 %) and rainfall erosivity (82 %) occurs between June and October. At a regional scale, rainfall erosivity increases from the north to the south during July and August, the most erosive months. For the remainder of the year, this gradient occurs mostly from northwest to southeast. Relief features strongly influence the spatial distribution of rainfall erosivity at a smaller scale, with the coastal plains and coastal mountain range having greater rainfall erosivity than the inland Abukuma River valley. Understanding these patterns, particularly their spatial and temporal (both inter- and intraannual) variation, is important for contextualizing soil and particle-bound radiocesium transfers in the Fukushima region. Moreover, understanding the impact of tropical cyclones will be important for managing sediment and sediment-bound contaminant

  9. Quantifying sources of fine sediment supplied to post-fire debris flows using fallout radionuclide tracers

    NASA Astrophysics Data System (ADS)

    Smith, H. G.; Sheridan, G. J.; Nyman, P.; Child, D.; Lane, P. N.; Hotchkis, M.

    2011-12-01

    The supply of fine sediment and ash has been identified as an important factor contributing to the initiation of runoff-generated debris flows after fire. However, despite the significance of fines for post-fire debris flow generation, no investigations have sought to quantify sources of this material in debris flow affected catchments. In this study, we employ fallout radionuclides (Cs-137, excess Pb-210 and Pu-239,240) as tracers to measure proportional contributions of fine sediment (<10 μm) from hillslope surface and channel bank sources to levee and terminal fan deposits formed by post-fire debris flows in two forest catchments in southeastern Australia. While Cs-137 and excess Pb-210 have been widely used in sediment tracing studies, application of Pu as a tracer represents a recent development and was limited to only one catchment. The estimated range in proportional hillslope surface contributions of fine sediment to individual debris flow deposits in each catchment was 22-69% and 32-74%. No systematic change in the proportional source contributions to debris flow deposits was observed with distance downstream from channel initiation points. Instead, spatial variability in source contributions was largely influenced by the pattern of debris flow surges forming the deposits. Linking the tracing analysis with interpretation of depositional evidence allowed reconstruction of temporal sequences in sediment source contributions to debris flow surges. Hillslope source inputs dominated most elevated channel deposits such as marginal levees that were formed under peak flow conditions. This indicated the importance of hillslope runoff and fine sediment supply for debris flow generation in both catchments. In contrast, material stored within channels that was deposited during subsequent surges was predominantly channel-derived. The results demonstrate that fallout radionuclide tracers may provide unique information on the changing source contributions of fine

  10. Quantifying sources of fine sediment supplied to post-fire debris flows using fallout radionuclide tracers

    NASA Astrophysics Data System (ADS)

    Smith, Hugh G.; Sheridan, Gary J.; Nyman, Petter; Child, David P.; Lane, Patrick N. J.; Hotchkis, Michael A. C.; Jacobsen, Geraldine E.

    2012-02-01

    Fine sediment supply has been identified as an important factor contributing to the initiation of runoff-generated debris flows after fire. However, despite the significance of fines for post-fire debris flow generation, no investigations have sought to quantify sources of this material in debris flow affected catchments. In this study, we employ fallout radionuclides ( 137Cs, 210Pb ex and 239,240Pu) as tracers to measure proportional contributions of fine sediment (< 10 μm) from hillslope surface and channel bank sources to levee and terminal fan deposits formed by post-fire debris flows in two forest catchments in southeastern Australia. While 137Cs and 210Pb ex have been widely used in sediment tracing studies, application of Pu as a tracer represents a recent development and was limited to only one catchment. The ranges in estimated proportional hillslope surface contributions of fine sediment to individual debris flow deposits in each catchment were 22-69% and 32-74%. The greater susceptibility of 210Pb ex to apparent reductions in the ash content of channel deposits relative to hillslope sources resulted in its exclusion from the final analysis. No systematic change in the proportional source contributions to debris flow deposits was observed with distance downstream from channel initiation points. Instead, spatial variability in source contributions was largely influenced by the pattern of debris flow surges forming the deposits. Linking the tracing analysis with interpretation of depositional evidence allowed reconstruction of temporal sequences in sediment source contributions to debris flow surges. Hillslope source inputs dominated most elevated channel deposits such as marginal levees that were formed under peak flow conditions. This indicated the importance of hillslope runoff and fine sediment supply for debris flow generation in both catchments. In contrast, material stored within channels that was deposited during subsequent surges was predominantly

  11. Quantifying sources of fine sediment supplied to post-fire debris flows using fallout radionuclide tracers

    NASA Astrophysics Data System (ADS)

    Smith, Hugh; Sheridan, Gary; Nyman, Petter; Child, David; Lane, Patrick; Hotchkis, Michael

    2013-04-01

    The supply of fine sediment and ash has been identified as an important factor contributing to the initiation of runoff-generated debris flows after fire. However, despite the significance of fines for post-fire debris flow generation, no investigations have sought to quantify sources of this material in debris flow affected catchments. In this study, we employ fallout radionuclides (Cs-137, excess Pb-210 and Pu-239,240) as tracers to measure proportional contributions of fine sediment (<10 μm) from hillslope surface and channel bank sources to levee and terminal fan deposits formed by post-fire debris flows in two forest catchments in southeastern Australia. While Cs-137 and excess Pb-210 have been widely used in sediment tracing studies, application of Pu as a tracer represents a recent development and was limited to only one catchment. The estimated range in hillslope surface contributions of fine sediment to individual debris flow deposits in each catchment was 22-69% and 32-74%, respectively. No systematic change in the source contributions to debris flow deposits was observed with distance downstream from channel initiation points. Instead, spatial variability in source contributions was largely influenced by the pattern of debris flow surges forming the deposits. Linking the sediment tracing with interpretation of depositional evidence allowed reconstruction of temporal sequences in sediment source contributions to debris flow surges. Hillslope source inputs dominated most elevated channel deposits such as marginal levees that were formed under peak flow conditions. This indicated the importance of hillslope runoff and sediment supply for debris flow generation in both catchments. In contrast, material stored within channels that was deposited during subsequent surges was predominantly channel-derived. The results demonstrate that fallout radionuclide tracers may provide unique information on the changing source contributions of fine sediment during debris

  12. Dose assessment for sheep exposed to fallout from nuclear test Nancy

    SciTech Connect

    Sasser, L.B.; Soldat, J.K.; Kennedy, W.E. Jr.; Murphy, D.W.

    1982-10-01

    Radiation doses were estimated for sheep wintering on Nevada ranges during the testing at the Nevada Test Site of the nuclear weapon Nancy on March 24, 1953. Exposure pathways considered were inhalation of radionuclides from both cloud passage and resuspension, external exposure of the total body and skin, and ingestion of contaminated forage and soil. Physiological, metabolic, and dosimetric data needed for these calculations were obtained from data appropriate for the sheep. Dose rate and radionuclide deposition values for shot Nancy were used. Radionuclide deposition and retention on the desert vegetation were obtained from data collected during several nuclear tests at the Nevada Test Site. Existing dosimetric computer programs, whose libraries were modified to include the sheep data, and specially developed models were used to estimate the dose commitment for the sheep. The total-body dose for reference sheep located within the 40-mR/hr (H+12) isopleth from all modes of exposure was estimated to be 2.6 rad. Ingestion of fallout on edible vegetation contributed the majority of the dose, whereas inhalation of radionuclides and consumption of contaminated soil from the ground contributed little to the internal doses. The dose to the thyroid of ewes from radioiodine and other radionuclides reaching the thyroid was approximately 400 rad. The calculated uniform dose to the reticulo-rumen was 4 rad; however, if fallout particles were assumed to concentrate in the ventral rumen, a localized dose of 200 rad could have been received by the rumen wall. Estimated dose to the bare skin of ewes was 120 rad. The dose to the fetal thyroid from radioiodine ingested by a pregnant ewe grazing at a location where the dose rate was 40 mR/hr (H+12) was estimated to be 700 rad, or approximately twice the dose to the maternal thyroid.

  13. Tephra-fallout hazard of Violent Strombolian eruptions at Vesuvius: insights from the 1906 event

    NASA Astrophysics Data System (ADS)

    Barsotti, Sara; D'Oriano, Claudia; Neri, Augusto; Cioni, Raffaello; Mulas, Maurizio

    2013-04-01

    Mt. Vesuvius is one of the most studied volcano in the world and its vicinity to an extremely populated area makes it also one of the most threatening. Violent Strombolians (VS) events have occurred in the most recent history of the volcano and are likely to occur in case of its reactivation in the future. In order to assess the regional hazard of this eruptive category we performed new field work and adopted a dispersal code to simulate the associated tephra dispersal and fallout. Attention was specifically focused on the 1906 event. Based on field analyses and historical observations, we reconstructed the temporal evolution of the eruptive source conditions during the event. We assumed a 5-day long scenario characterized by two distinct phases: a former short and intense phase of lava fountaining followed by a prolonged weaker phase of ash emission. Grain-size distributions adopted, for the two phases, as input to the model were derived from deposit records accounting also for the presence of sub-micron particles. Based on simplified reconstructions of wind field directions, we simulated the 1906 event and compared it with field data in order to evaluate the validity of the event characterization as well as the model performance. In particular, model outcomes were compared to refined field measurements and deposit distributions. In addition, several hypothetical scenarios with the same source conditions were simulated by adopting realistic meteorological data. Results are shown for specific cases in terms of hazard assessment on the ground (ash deposition and ash concentration in the air). The model clearly highlighted the remarkable effect of the variable local meteorology on ash dispersal and the key role of wind shear on the final cumulative ground deposit. In particular, the prevailing zonal wind, present at this latitude, demonstrated how ash fallout on the city of Naples is a possible scenario to be considered. Lastly, the effect of wet deposition and

  14. Thyroid hypofunction after exposure to fallout from a hydrogen bomb explosion.

    PubMed

    Larsen, P R; Conard, R A; Knudsen, K D; Robbins, J; Wolff, J; Rall, J E; Nicoloff, J T; Dobyns, B M

    1982-03-19

    Thyroid function was evaluated in the Marshallese who were accidentally exposed to fallout-containing radioiodine isotopes in 1954. Measurements of thyrotrophin (TSH, thyroid-stimulating hormone) levels and free thyroxine (T4) index (FT4I) have revealed that, among 86 persons exposed on Rongelap and Ailingnae atolls, 14 have shown evidence of thyroid hypofunction. This was first noted in some individuals about ten years after exposure. Only two of these showed clinical evidence of hypothyroidism. The most marked TSH elevations were noted in nine persons exposed when younger than 6 years, with estimated doses to the thyroid from 390 to 2,100 rad. Most of this group subsequently had surgery for removal of thyroid nodules. The remaining five cases have been noted more recently among 36 surviving adults exposed at an older age who showed no other detectable thyroid abnormalities. This group had received estimated thyroid doses ranging from 135 to 335 rad and showed modest elevation of serum TSH levels (6 to 9 microU/mL) and a slightly subnormal FT4I. No abnormalities were found in persons on Utirik who received substantially less radiation, and hypothyroidism was present in less than 1% of the control, unexposed Marshallese. The high prevalence of a thyroid hypofunction in these persons indicates that this condition, as well as thyroid nodularity, can be a delayed complication of exposure to early fallout from a nuclear explosion. The fact that a significant fraction of the radiation to the thyroid was from short-lived radioiodine isotopes (132I, 133I, 135I), as opposed to 131I, may account for the severity of the thyroid damage.

  15. Estimation of immediate fallout after the accident at Fukushima Daiichi Nuclear Power Plant by using HPGe detector and EGS5 code.

    PubMed

    Unno, Yasuhiro; Yunoki, Akira; Sato, Yasushi; Hino, Yoshio

    2013-11-01

    After the accident at the Fukushima Daiichi nuclear power plant, we managed to carry out emergency measurements of the radioactive fallout. The included nuclides were identified via gamma-ray spectrometry using an HPGe detector. Quantifications of each radionuclide in the fallout were determined based on the efficiency calibrations and relevant corrections. The collected samples had a variety of shapes, densities, and compositions. EGS5 Monte Carlo code was used for the flexible estimation of these parameters. The measurement results show the temporal changes in the fallout quantity about a month after the accident.

  16. Atomic supersymmetry

    NASA Technical Reports Server (NTRS)

    Kostelecky, V. Alan

    1993-01-01

    Atomic supersymmetry is a quantum-mechanical supersymmetry connecting the properties of different atoms and ions. A short description of some established results in the subject are provided and a few recent developments are discussed including the extension to parabolic coordinates and the calculation of Stark maps using supersymmetry-based models.

  17. Relative effectiveness of structures as protection from gamma radiation from cloud and fallout sources as a function of source energy. Doctoral thesis

    SciTech Connect

    Fingerlos, J.P.

    1984-01-01

    Point kernel models were developed for both fallout and cloud sources. That development included a method of accurately combining buildup factors in multi-region problems over wide ranges of energy and photon mean free path, and a method for calculating the effect of ground roughness on the attenuation factor for fallout sources. The results were reported for six spectra as well as discrete energies from 15 keV to 15 MeV. The structures used as examples include small wood frame and large brick houses. The results show that the protection provided by houses for the PWR-2 event is approximately equal to that for the 1-hr weapon fallout. However there are significant differences for other spectra, such as that from Three Mile Island. The effects of varying building size are reported as well as the relative importance of both cloud and fallout sources that infiltrate structures. A listing of computer program CLOUD is provided.

  18. Acting Atoms.

    ERIC Educational Resources Information Center

    Farin, Susan Archie

    1997-01-01

    Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

  19. Kinetic Atom.

    ERIC Educational Resources Information Center

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  20. Assessment of the global fallout of plutonium isotopes and americium-241 in the soil of the central region of Saudi Arabia.

    PubMed

    Shabana, E I; Al-Shammari, H L

    2001-01-01

    A radiochemical technique for determination of plutonium isotopes and 241Am in soil samples is tested against IAEA-standard reference materials to determine its accuracy and precision for reliable results. The technique is then used in the investigation of topsoil samples, collected from the natural environment of the central region of Saudi Arabia, to assess the effect of fallout accumulation of these radionuclides in the region. Plutonium and americium were sequentially separated from all other components of the sample by anion-exchange chromatography and co-precipitated with Nd3+ as fluorides. The precipitates were mounted on membrane filters and measured using a high-resolution alpha-spectrometer. The results of the analysis of the reference materials showed satisfactory sensitivity and precision of the technique. The results of the analyzed soil samples show activity levels ranging from < LLD to 0.089 and from ratios ranged from 0 to 0.216 and 0.3-1.23, respectively. A discussion based on the observed data is presented.

  1. The new conversion model MODERN to derive erosion rates from inventories of fallout radionuclides

    NASA Astrophysics Data System (ADS)

    Arata, Laura; Meusburger, Katrin; Frenkel, Elena; A'Campo-Neuen, Annette; Iurian, Andra-Rada; Ketterer, Michael E.; Mabit, Lionel; Alewell, Christine

    2016-04-01

    The measurement of fallout radionuclides (FRNs) has become one of the most commonly used methods to quantify soil erosion and depositional processes. FRNs include anthropogenic radionuclides (e.g. 137Cs, 239+240Pu) released into the atmosphere during nuclear bomb tests and power plant accidents (e.g Chernobyl, Fukushima-Daiichi), as well as natural radiotracers such as 210Pbex and 7Be. FRNs reach the land surface by dry and wet fallouts from the atmosphere. Once deposited, FRNs are tightly adsorbed by fine soil particles and their subsequent redistribution is mostly associated with soil erosion processes. FRNs methods are based on a qualitative comparison: the inventory (total radionuclide activity per unit area) at a given sampling site is compared to that of a so called reference site. The conversion of FRN inventories into soil erosion and deposition rates is done with a variety of models, which suitability is dependent on the selected FRN, soil cultivation (ploughed or unploughed) and movement (erosion or deposition). The authors propose a new conversion model, which can be easily and comprehensively used for different FRNs, land uses and soil redistribution processes. This new model i.e. MODERN (MOdelling Deposition and Erosion rates with RadioNuclides) considers the precise depth distribution of a given FRN at a reference site, and allows adapting it for any specific site conditions. MODERN adaptability and performance has been tested on two published case studies: (i) a 137Cs study in an alpine and unploughed area in the Aosta valley (Italy) and (ii) a 210Pbex study on a ploughed area located in Romania. The results show a good agreement and a significant correlation (r= 0.91, p<0.0001) between the results of MODERN and the published models currently used by the FRN scientific community (i.e. the Profile Distribution Model and the Mass Balance Model). The open access code and the cost free accessibility of MODERN will ensure the promotion of a wider

  2. Sr-Nd isotopic variations in the 4,965 yr BP "Ochre Pumice" plinian fallout of Popocatépetl: Preliminary results and interpretation

    NASA Astrophysics Data System (ADS)

    Orsi, G.; Arana-Salinas, L.; Civetta, L.; Siebe, C.

    2013-05-01

    becomes more silicic towards the top (SiO2 = 63 wt.%). Pumice clasts have a crystallinity index that ranges between 10 and 25 Vol.% and display a seriate texture. Phenocrysts of plagioclase are the most abundant phase and typically display labradoritic cores (An54-59) and andesine rims (An41-46). Augites (En40-44 Wo41-45) and hypersthenes (En66-40) are less common, occur either isolated or in clusters with plagioclase and/or olivine. Ol-crystals are slightly zoned with forsteritic core compositions (Fo65-Fo84). Apatite and opaques occur subordinately. This study aims to determine systematically the Sr-Nd isotopic ratios in the different layers that compose the plinian "Ochre pumice" fallout sequence in order to make inferences regarding magmatic processes (mafic injection, mixing, mingling, etc.) prior to eruption. Preliminary results and interpretations will be presented.

  3. Polybrominated diphenyl ethers in air and fallouts from an e-waste polluted region in southeast China: insight into levels, compositional profiles, and seasonal variation.

    PubMed

    Xu, Feng; Zhang, Gang; Wang, Junxia; Zhang, Wei; Liu, Lili; Lin, Kuangfei

    2015-12-01

    Air and fallout samples were collected seasonally in an e-waste polluted region in southeast of China in 2013-2014. The annual polybrominated diphenyl ethers (PBDEs) concentrations in air and fallout samples were 200 ± 162 pg m(-3) and 320 ± 255 ng g(-1), respectively. The deposition flux calculated from the fallout concentration was 110 ± 77.3 ng m(-2) day(-1). The PBDE levels and deposition fluxes of the samples deployed within the e-waste central area were three to four times higher than those in the surrounding area. The congener profiles in the air samples could be commonly found in commercial penta-BDE mixtures. BDE209 was the most dominant congener in fallout samples. Debromination processes were confirmed to occur both in the air and fallouts due to the minor amounts or inexistence of some congeners in technical PBDE products. The highest gaseous PBDE concentration was found during the summer while lowest during the autumn. PBDE concentration in fallouts turned up higher in the cold months while lower in the warm months. The similarity of deposition fluxes at sites in the e-waste central area indicated a steady PBDE emission source, whereas the significant relationship between deposition fluxes and particle weights at sites in the e-waste surrounding area suggested the scavenging of PBDEs in this area was largely associated with particles.

  4. An estimate by two methods of thyroid absorbed doses due to BRAVO fallout in several northern Marshall Islands

    SciTech Connect

    Musolino, S.V.; Hull, A.P.; Greenhouse, N.A.

    1997-10-01

    Estimates of the thyroid absorbed doses due to fallout originating from the 1 March 1954 BRAVO thermonuclear test on Bikini Atoll have been made for several inhabited locations in the Northern Marshall Islands. Rongelap, Utirik, Rongerik and Ailinginae Atolls were also inhabited on 1 March 1954, where retrospective thyroid absorbed doses have previously been reconstructed. Current estimates are based primarily on external exposure data, which were recorded shortly after each nuclear test in the Castle Series, and secondarily on soil concentrations of {sup 137}Cs in samples collected in 1978 and 1988, along with aerial monitoring done in 1978. External exposures and {sup 137}Cs Soil concentrations were representative of the atmospheric transport and deposition patterns of the entire Castle Series tests and show that the BRAVO test was the major contributor to fallout exposure during the Castle series and other test series which were carried out in the Marshall Islands. These data have been used as surrogates for fission product radioiodines and telluriums in order to estimate the range of thyroid absorbed doses that may have occurred throughout the Marshall Islands. Dosimetry based on these two sets of estimates agreed within a factor of 4 at the locations where BRAVO was the dominant contributor to the total exposure and deposition. Both methods indicate that thyroid absorbed doses in the range of 1 Gy (100 rad) may have been incurred in some of the northern locations, whereas the doses at southern locations did not significantly exceed levels comparable to those from worldwide fallout. The results of these estimates indicate that a systematic medical survey for thyroid disease should be conducted, and that a more definitive dose reconstruction should be made for all the populated atolls and islands in the Northern Marshall Islands beyond Rongelap, Utirik, Rongerik and Ailinginae, which were significantly contaminated by BRAVO fallout. 30 refs., 2 figs., 10 tabs.

  5. An estimate by two methods of thyroid absorbed doses due to BRAVO fallout in several Northern Marshall Islands.

    PubMed

    Musolino, S V; Greenhouse, N A; Hull, A P

    1997-10-01

    Estimates of the thyroid absorbed doses due to fallout originating from the 1 March 1954 BRAVO thermonuclear test on Bikini Atoll have been made for several inhabited locations in the Northern Marshall Islands. Rongelap, Utirik, Rongerik and Ailinginae Atolls were also inhabited on 1 March 1954, where retrospective thyroid absorbed doses have previously been reconstructed. The current estimates are based primarily on external exposure data, which were recorded shortly after each nuclear test in the Castle Series, and secondarily on soil concentrations of 137Cs in samples collected in 1978 and 1988, along with aerial monitoring done in 1978. The external exposures and 137Cs soil concentrations were representative of the atmospheric transport and deposition patterns of the entire Castle Series tests and show that the BRAVO test was the major contributor to fallout exposure during the Castle series and other test series which were carried out in the Marshall Islands. These data have been used as surrogates for fission product radioiodines and telluriums in order to estimate the range of thyroid absorbed doses that may have occurred throughout the Marshall Islands. Dosimetry based on these two sets of estimates agreed within a factor of 4 at the locations where BRAVO was the dominant contributor to the total exposure and deposition. Both methods indicate that thyroid absorbed doses in the range of 1 Gy (100 rad) may have been incurred in some of the northern locations, whereas the doses at southern locations did not significantly exceed levels comparable to those from worldwide fallout. The results of these estimates indicate that a systematic medical survey for thyroid disease should be conducted, and that a more definitive dose reconstruction should be made for all the populated atolls and islands in the Northern Marshall Islands beyond Rongelap, Utirik, Rongerik and Ailinginae, which were significantly contaminated by BRAVO fallout.

  6. On the occurrence of radioactive fallout over Norway as a result of the Windscale accident, October 1957.

    PubMed

    Bergan, T; Dowdall, M; Selnaes, O G

    2008-01-01

    A fire at the Windscale plant at Cumbria in the UK between the 10th and the 11th of October 1957 resulted in the first publicised release of radioactivity to the wider environment. The cloud of contamination passed to the southeast of England before travelling northwards on the 14th of October as a result of weather fronts in Europe. Monitoring of radioactive fallout in Norway was at the time conducted by the Norwegian Defence Research Establishment (FFI) using a network of air and precipitation monitoring stations. This article presents results from these monitoring activities which were originally contained in laboratory journals and a series of internal reports produced by FFI. Although mainly classified during the 1950s and 1960s, recent years have seen the incremental declassification of these reports and as the 50th anniversary of the accident approaches, a distillation and reanalysis of this information has been conducted. Results indicate that radioactivity from Windscale was first detected at Bergen and Sola in the south west of Norway and a little later at Vaernes, significant amounts of radioactivity being deposited at these locations during the second and third weeks of that month. Results relating to concentrations of activity in air and precipitation and fallout levels are presented for the relevant period and discussed in relation to fallout levels in Norway during the period 1957-1960.

  7. The effect of wind and eruption source parameter variations on tephra fallout hazard assessment: an example from Vesuvio (Italy)

    NASA Astrophysics Data System (ADS)

    Macedonio, Giovanni; Costa, Antonio; Scollo, Simona; Neri, Augusto

    2015-04-01

    Uncertainty in the tephra fallout hazard assessment may depend on different meteorological datasets and eruptive source parameters used in the modelling. We present a statistical study to analyze this uncertainty in the case of a sub-Plinian eruption of Vesuvius of VEI = 4, column height of 18 km and total erupted mass of 5 × 1011 kg. The hazard assessment for tephra fallout is performed using the advection-diffusion model Hazmap. Firstly, we analyze statistically different meteorological datasets: i) from the daily atmospheric soundings of the stations located in Brindisi (Italy) between 1962 and 1976 and between 1996 and 2012, and in Pratica di Mare (Rome, Italy) between 1996 and 2012; ii) from numerical weather prediction models of the National Oceanic and Atmospheric Administration and of the European Centre for Medium-Range Weather Forecasts. Furthermore, we modify the total mass, the total grain-size distribution, the eruption column height, and the diffusion coefficient. Then, we quantify the impact that different datasets and model input parameters have on the probability maps. Results shows that the parameter that mostly affects the tephra fallout probability maps, keeping constant the total mass, is the particle terminal settling velocity, which is a function of the total grain-size distribution, particle density and shape. Differently, the evaluation of the hazard assessment weakly depends on the use of different meteorological datasets, column height and diffusion coefficient.

  8. Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

    NASA Astrophysics Data System (ADS)

    Coppin, Frederic; Hurtevent, Pierre; Loffredo, Nicolas; Simonucci, Caroline; Julien, Anthony; Gonze, Marc-Andre; Nanba, Kenji; Onda, Yuichi; Thiry, Yves

    2016-11-01

    Our study focused on radiocaesium (137Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. 137Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0–3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61–69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees’ residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial 137Cs deposit for mature and young cedars, respectively.

  9. Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

    PubMed Central

    Coppin, Frederic; Hurtevent, Pierre; Loffredo, Nicolas; Simonucci, Caroline; Julien, Anthony; Gonze, Marc-Andre; Nanba, Kenji; Onda, Yuichi; Thiry, Yves

    2016-01-01

    Our study focused on radiocaesium (137Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. 137Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0–3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61–69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees’ residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial 137Cs deposit for mature and young cedars, respectively. PMID:27876870

  10. Genetic consequences of radioactive contamination by the Chernobyl fallout to agricultural crops.

    PubMed

    Geraskin, S A; Dikarev, V G; Zyablitskaya, Ye Ya; Oudalova, A A; Spirin, Ye V; Alexakhin, R M

    2003-01-01

    The genetic consequences of radioactive contamination by the fallout to agricultural crops after the accident at the Chernobyl NPP in 1986 have been studied. In the first, acute, period of this accident, when the absorbed dose was primarily due to external beta- and gamma-irradiation, the radiation injury of agricultural crops, according to the basic cytogenetic tests, resembled the effect produced by acute gamma-irradiation at comparable doses. The yield of cytogenetic damage in leaf meristem of plants grown in the 10-km zone of the ChNPP in 1987-1989 (the period of chronic, lower level radiation exposure) was shown to be enhanced and dependent on the level of radioactive contamination. The rate of decline with time in cytogenetic damage induced by chronic exposure lagged considerably behind that of the radiation exposure. Analysis of genetic variability in three sequential generations of rye and wheat revealed increased cytogenetic damage in plants exposed to chronic irradiation during the 2nd and 3rd years.

  11. Northern conditions influencing the selection of countermeasures after radioactive fallout in Finland.

    PubMed

    Root, Tarja; Tattari, Sirkka; Rantavaara, Aino

    2005-01-01

    The paper summarizes an evaluation of practicability of rural countermeasures after radioactive fallout in northern conditions carried out by a Finnish group of experts in the FARMING Network project. Snow and soil frost limit the selection of crops, and the short growing season allows mostly one harvest yearly. Cold climate restricts fruit production to apples and berries. Due to the long indoor feeding period, conserved and stored clean feed is available almost all year round. The use of fertilisers and lime on poor and acidic soils leads to high potassium and calcium intake of cows increasing the incidence of milk fever. The surface soil layer is thin and ploughing deeper than 20 cm is problematic due to stony and compacted soils. It also increases soil acidity and decreases fertility. Cultivation of peatlands limits the selection of plants and increases long-term radiocaesium contamination of crops. Frost and snow delay ploughing and spreading of waste milk on arable land, but removal of snow is a decontamination option. Long distances and high transport costs complicate carrying out the countermeasures. The Finnish stakeholder group considered it vital to be prepared for implementation of practicable measures for the safety of food.

  12. April-May 2010 Eyjafjallajökull volcanic fallout over Rimini, Italy

    NASA Astrophysics Data System (ADS)

    Rossini, Paolo; Molinaroli, Emanuela; De Falco, Giovanni; Fiesoletti, Federica; Papa, Stefano; Pari, Elena; Renzulli, Alberto; Tentoni, Pierpaolo; Testoni, Alessio; Valentini, Laura; Matteucci, Gabriele

    2012-03-01

    Located at a distance of approximately 3200 km from Iceland, where the Eyjafjallajökull volcano erupted, Italy was affected by volcanic ash transported by middle altitude air masses across Europe. Volcanic emissions from the Eyjafjallajökull eruption in April 2010 were detected in Rimini (44° 2' 28" N, 12° 34' 3" E) (Italy) by means of in-situ measurements (sampling of bulk depositions). Sampling was carried out during the period April-August 2010, and the following parameters were determined: grain size, TSP, mineralogy, particle morphology and chemical content in terms of Br -, Cl -, F -, SO42-, Al, As, Ba, Be, Ca, Cd, Ce, Co, Cr, Cu, Fe, Hg, K, Li, Lu, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Se, Si, Sn, Sr, Tb, Te, Ti, Tl, U, V, Y, Zn and Zr. Information from the Hysplit-NOAA back trajectory helped to identify the origin of the air mass. The results obtained from the observations are in good agreement with similar studies carried out by other European scientists, confirming that the Eyjafjallajökull ash plume also had a surface impact in Italy. The findings of our study support observations made by researchers of the CNR-IMAA Atmospheric Observatory at the EARLINET station in Southern Italy and enlarge the geographical area known to have been affected by fallout from the April-May 2010 eruption of the Eyjafjallajökull volcano.

  13. The impact of Chernobyl fallout on the Southern Saami reindeer herders of Norway in 1996.

    PubMed

    Mehli, H; Skuterud, L; Mosdøl, A; Tønnessen, A

    2000-12-01

    The reindeer-herding Southern Saamis, from Central Norway, were the population group exposed to the highest levels of radioactivity in Norway, following the Chernobyl accident. Radiocesium whole-body contents and dietary habits have been investigated regularly in this population group since 1987. Meat of semi-domesticated reindeer is important in their diet, and earlier studies have shown that contaminated reindeer meat contributes about 90% to the total intake of radiocesium. A major part of the group also consumes wild food products like game, freshwater fish, mushrooms, and berries. The application of countermeasures has been a common practice for the reindeer herders since the Chernobyl accident. According to the interviews in 1996, the three most commonly used and socially accepted countermeasures were (1) selection of reindeer for consumption after live monitoring of radiocesium concentrations; (2) selection of reindeer for consumption from less contaminated grazing areas; and (3) clean feeding of animals before slaughtering. Despite these countermeasures about one third of the population still have reduced reindeer meat intake because of the Chernobyl fallout. In 1996, the average whole body concentration of 137Cs for this population was found to be 88+/-7 Bq kg(-1) for women and 164+/-11 Bq kg(-1) for men(arithmetic mean +/- standard error). This is approximately half of the whole-body concentration of 137Cs measured in the same population in 1990-1991.

  14. GLODEP2: a computer model for estimating gamma dose due to worldwide fallout of radioactive debris

    SciTech Connect

    Edwards, L.L.; Harvey, T.F.; Peterson, K.R.

    1984-03-01

    The GLODEP2 computer code provides estimates of the surface deposition of worldwide radioactivity and the gamma-ray dose to man from intermediate and long-term fallout. The code is based on empirical models derived primarily from injection-deposition experience gained from the US and USSR nuclear tests in 1958. Under the assumption that a nuclear power facility is destroyed and that its debris behaves in the same manner as the radioactive cloud produced by the nuclear weapon that attached the facility, predictions are made for the gamma does from this source of radioactivity. As a comparison study the gamma dose due to the atmospheric nuclear tests from the period of 1951 to 1962 has been computed. The computed and measured values from Grove, UK and Chiba, Japan agree to within a few percent. The global deposition of radioactivity and resultant gamma dose from a hypothetical strategic nuclear exchange between the US and the USSR is reported. Of the assumed 5300 Mton in the exchange, 2031 Mton of radioactive debris is injected in the atmosphere. The highest estimated average whole body total integrated dose over 50 years (assuming no reduction by sheltering or weathering) is 23 rem in the 30 to 50 degree latitude band. If the attack included a 100 GW(e) nuclear power industry as targets in the US, this dose is increased to 84.6 rem. Hotspots due to rainfall could increase these values by factors of 10 to 50.

  15. 'Do-it-yourself' fallout/blast shelter evaluation. Final report

    SciTech Connect

    Nash, P.T.; Baker, W.E.; Esparza, E.D.; Westine, P.S.; Blaylock, N.W.

    1984-03-01

    Expedient fallout shelters recommended to the general public were evaluated for their potential to provide safety to occupants during nuclear blast. The blast threat was in the 2 to 50 psi overpressure range from a 1 megaton (MT) yield weapon. Research included a literature search for expedient shelter designs and evaluations of the designs to certify their ability to protect occupants. Shelters were evaluated systematically by first analyzing each design for expected failure loads. Next, scale model tests were planned and conducted in the Fort Cronkhite shock tunnel. Structural responses and blast pressures were recorded in a series of twelve experiments involving 96 structural response models. Two rigid models were included in each test to measure internal blast pressure leakage. Probabilities of survival were determined for each of the shelters tested. Expected failure mechanisms were identified for each of the eight U.S. shelters. One shelter, tilt-up doors and earth, was eliminated from consideration because of uncertainties for the associated permanent structure. Failure loads of the remaining seven shelters were determined through analysis. Analyses included failure by overturning/translation, trench collapse, or roof collapse. A car-over-trench shelter was evaluated solely through analysis. The threshold for human tolerance to blast pressures (lung damage) was calculated as 8 psi with a 99 percent survival rate at 28 psi. Thresholds for trench wall stability were calculated based on material strengths and shelter geometries.

  16. Spatial distribution of fallout 137Cs in the coastal marine environment of India.

    PubMed

    Jha, S K; Gothankar, S S; Sartandel, S; Pote, M B; Hemalatha, P; Rajan, M P; Vidyasagar, D; Indumati, S P; Shrivastava, R; Puranik, V D

    2012-11-01

    The data on the fallout (137)Cs in the coastal marine environment assume significance in view of massive expansion of nuclear power plants in the Asia-Pacific region and to fulfill the benchmark study required to evaluate the possible impact of the Fukushima radioactive releases in the Asia-Pacific region. Measurements of (137)Cs in sea water, along with salinity and temperature, were carried out at 30 locations covering the coastal area of the Arabian Sea and the Bay of Bengal. For the present study the Indian coastal area is divided in three different regions. The (137)Cs concentration in sea water of the entire Indian coastal region varies from 0.30 to 1.25 Bq m(-3). The data obtained in the present study was compared with the North Indian Ocean data and it was observed that there is a 33% decrease in the Arabian Sea (region I), 50% in the high rainfall coastal area (region II) and 24% in the Bay of Bengal (region III).

  17. Deposition in Chiba prefecture, Japan, of Fukushima Daiichi Nuclear Power Plant fallout.

    PubMed

    Ishii, Nobuyoshi; Tagami, Keiko; Takata, Hyoe; Fujita, Kazuhiro; Kawaguchi, Isao; Watanabe, Yoshito; Uchida, Shigeo

    2013-02-01

    Radioactivity from the Fukushima Daiichi Nuclear Power Plant (F-1NPP) accident in deposition samples has been monitored at the National Institute of Radiological Sciences (NIRS) in Chiba Prefecture, Japan, located about 220 km south-southwest of the F-1NPP. Sampling was carried out from 15 March 2011, two to three times a day for 10 d and then once a day until 22 April 2011. Gamma-ray spectrometry of fallout deposition samples revealed the presence of (131)I, (132)I, (132)Te, (134)Cs, and (137)Cs. The largest deposition was observed during 7:00-16:00 on 21 March. The estimated total deposition densities at NIRS were 1.40 × 10(5) Bq m(-2) for (131)I, 4.12 × 10(4) Bq m(-2) for (132)Te, 1.45 × 10(4) Bq m(-2) for (134)Cs, and 1.48 × 10(4) Bq m(-2) for (137)Cs (corrected to 11 March 2011). The obtained densities of (134)Cs and (137)Cs were also supported by the accumulated amount of (134)Cs and (137)Cs in soil near the deposition sampling site. For the vertical profile of those radionuclides in soil at NIRS, about 94% of the total deposition was distributed in the top 10 mm depth on 26 April 2011.

  18. Radiocaesium partitioning in Japanese cedar forests following the "early" phase of Fukushima fallout redistribution.

    PubMed

    Coppin, Frederic; Hurtevent, Pierre; Loffredo, Nicolas; Simonucci, Caroline; Julien, Anthony; Gonze, Marc-Andre; Nanba, Kenji; Onda, Yuichi; Thiry, Yves

    2016-11-23

    Our study focused on radiocaesium ((137)Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. (137)Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0-3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61-69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees' residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial (137)Cs deposit for mature and young cedars, respectively.

  19. Radioactivity in persons exposed to fallout from the Chernobyl reactor accident

    SciTech Connect

    Schlenker, R.A.; Oltman, B.G.; Lucas, H.F.

    1987-01-01

    Measurements of fallout radioactivity were made in the thyroid region, abdomen, whole body, or urine of 96 persons who were in eastern Europe at the time of the Chernobyl reactor accident or who went there shortly afterward. The most frequently encountered radionuclides were /sup 131/I, sup 134,137/Cs, and /sup 103/Ru//sup 103/Rh. The median /sup 131/I activity in the thyroids of 42 subjects in whom radioiodine was detected and who were in Europe when the accident began was projected as 42 nCi the day the accident began. The median total body activity of /sup 134/Cs in 40 subjects in which it was detected was 1.7 nCi upon arrival in the US. For 51 subjects with detectable /sup 137/Cs burdens, the total body activity was 4.6 nCi. The risk of fatal thyroid cancer is less than 3 x 10/sup -6/ for nearly all subjects in this series. The risk of fatal cancer from /sup 134,137/Cs for subjects with cesium exposures similar to the ones observed by us, but who remained in Europe, is estimated as 1.4 x 10/sup -6/ to 4.2 x 10/sup -5/ with 95% of the risk attributable to /sup 137/Cs. 5 refs., 4 tabs.

  20. Yttrium and lanthanides in human lung fluids, probing the exposure to atmospheric fallout.

    PubMed

    Censi, P; Tamburo, E; Speziale, S; Zuddas, P; Randazzo, L A; Punturo, R; Cuttitta, A; Aricò, P

    2011-02-28

    Inhalation of airborne particles can produce crystallization of phosphatic microcrysts in intraaveolar areas of lungs, sometimes degenerating into pulmonary fibrosis. Results of this study indicate that these pathologies are induced by interactions between lung fluids and inhaled atmospheric dust in people exposed to volcanic dust ejected from Mount Etna in 2001. Here, the lung solid-liquid interaction is evaluated by the distribution of yttrium and lanthanides (YLn) in fluid bronchoalveolar lavages on selected individuals according the classical geochemical approaches. We found that shale-normalised patterns of yttrium and lanthanides have a 'V shaped' feature corresponding to the depletion of elements from Nd to Tb when compared to the variable enrichments of heavy lanthanides, Y, La and Ce. These features and concurrent thermodynamic simulations suggest that phosphate precipitation can occur in lungs due to interactions between volcanic particles and fluids. We propose that patterns of yttrium and lanthanides can represent a viable explanation of some pathology observed in patients after prolonged exposure to atmospheric fallout and are suitable to become a diagnostic parameter of chemical environmental stresses.

  1. Atomic research

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.; Connatser, Robert; Cothren, Bobby; Johnson, R. B.

    1993-01-01

    Work performed by the University of Alabama in Huntsville's (UAH) Center for Applied Optics (CAO) entitled Atomic Research is documented. Atomic oxygen (AO) effects on materials have long been a critical concern in designing spacecraft to withstand exposure to the Low Earth Orbit (LEO) environment. The objective of this research effort was to provide technical expertise in the design of instrumentation and experimental techniques for analyzing materials exposed to atomic oxygen in accelerated testing at NASA/MSFC. Such testing was required to answer fundamental questions concerning Space Station Freedom (SSF) candidate materials and materials exposed to atomic oxygen aboard the Long-Duration Exposure Facility (LDEF). The primary UAH task was to provide technical design, review, and analysis to MSFC in the development of a state-of-the-art 5eV atomic oxygen beam facility required to simulate the RAM-induced low earth orbit (LEO) AO environment. This development was to be accomplished primarily at NASA/MSFC. In support of this task, contamination effects and ultraviolet (UV) simulation testing was also to be carried out using NASA/MSFC facilities. Any materials analysis of LDEF samples was to be accomplished at UAH.

  2. Assessing the long-term probabilistic volcanic hazard for tephra fallout in Reykjavik, Iceland: a preliminary multi-source analysis

    NASA Astrophysics Data System (ADS)

    Tonini, Roberto; Barsotti, Sara; Sandri, Laura; Tumi Guðmundsson, Magnús

    2015-04-01

    Icelandic volcanism is largely dominated by basaltic magma. Nevertheless the presence of glaciers over many Icelandic volcanic systems results in frequent phreatomagmatic eruptions and associated tephra production, making explosive eruptions the most common type of volcanic activity. Jökulhlaups are commonly considered as major volcanic hazard in Iceland for their high frequency and potentially very devastating local impact. Tephra fallout is also frequent and can impact larger areas. It is driven by the wind direction that can change with both altitude and season, making impossible to predict a priori where the tephra will be deposited during the next eruptions. Most of the volcanic activity in Iceland occurs in the central eastern part, over 100 km to the east of the main population centre around the capital Reykjavík. Therefore, the hazard from tephra fallout in Reykjavík is expected to be smaller than for communities settled near the main volcanic systems. However, within the framework of quantitative hazard and risk analyses, less frequent and/or less intense phenomena should not be neglected, since their risk evaluation depends on the effects suffered by the selected target. This is particularly true if the target is highly vulnerable, as large urban areas or important infrastructures. In this work we present the preliminary analysis aiming to perform a Probabilistic Volcanic Hazard Assessment (PVHA) for tephra fallout focused on the target area which includes the municipality of Reykjavík and the Keflavík international airport. This approach reverts the more common perspective where the hazard analysis is focused on the source (the volcanic system) and it follows a multi-source approach: indeed, the idea is to quantify, homogeneously, the hazard due to the main hazardous volcanoes that could pose a tephra fallout threat for the municipality of Reykjavík and the Keflavík airport. PVHA for each volcanic system is calculated independently and the results

  3. Atom Interferometry

    ScienceCinema

    Mark Kasevich

    2016-07-12

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  4. Atom Interferometry

    SciTech Connect

    Kasevich, Mark

    2008-05-08

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton's constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gyroscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be used to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  5. Atom Interferometry

    SciTech Connect

    Mark Kasevich

    2008-05-07

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  6. Cesium isotope ratios as indicators of nuclear power plant operations.

    PubMed

    Delmore, James E; Snyder, Darin C; Tranter, Troy; Mann, Nick R

    2011-11-01

    There are multiple paths by which radioactive cesium can reach the effluent from reactor operations. The radioactive (135)Cs/(137)Cs ratios are controlled by these paths. In an effort to better understand the origin of this radiation, these (135)Cs/(137)Cs ratios in effluents from three power reactor sites have been measured in offsite samples. These ratios are different from global fallout by up to six fold and as such cannot have a significant component from this source. A cesium ratio for a sample collected outside of the plant boundary provides integration over the operating life of the reactor. A sample collected inside the plant at any given time can be much different from this lifetime ratio. The measured cesium ratios vary significantly for the three reactors and indicate that the multiple paths have widely varying levels of contributions. There are too many ways these isotopes can fractionate to be useful for quantitative evaluations of operating parameters in an offsite sample, although it may be possible to obtain limited qualitative information for an onsite sample.

  7. Cesium Isotope Ratios as Indicators of Nuclear Power Plant Operations

    SciTech Connect

    Darin Snyder; James Delmore; Troy Tranter; Nick Mann; Michael Abbott; John Olson

    2011-11-01

    There are multiple paths by which radioactive cesium can reach the effluent from reactor operations. The radioactive 135Cs/137Cs ratios are controlled by these paths. In an effort to better understand the origin of this radiation, these 135Cs/137Cs ratios in effluents from three power reactor sites have been measured in offsite samples. These ratios are different from global fallout by up to six fold and as such cannot have a significant component from this source. A cesium ratio for a sample collected outside of the plant boundary provides integration over the operating life of the reactor. A sample collected inside the plant at any given time can be much different from this lifetime ratio. The measured cesium ratios vary significantly for the three reactors and indicate that the multiple paths have widely varying levels of contributions. There are too many ways these isotopes can fractionate to be useful for quantitative evaluations of operating parameters in an offsite sample, although it may be possible to obtain limited qualitative information for an onsite sample.

  8. Towards prediction of redistribution of fallout radiocesium on forested area discharged from Fukushima Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Miura, Satoru; Aoyama, Michio; Ito, Eriko; Shichi, Koji; Takata, Daisuke; Masaya, Masumori; Sekiya, Nobuhito; Kobayashi, Natsuko; Takano, Naoto; Kaneko, Shinji; Tanoi, Keitaro; Nakanishi, Tomoko

    2015-04-01

    Redistribution of fallout 137Cs on forested area discharged from Fukushima Nuclear Power Plant (FNPP) is an issue of major concern for the people in Fukushima and its surrounding areas. To approach this question we investigated global fallout 137Cs (137Cs-GFO) from nuclear weapon tests in the atmosphere in the 1950s and 60s, and 137Cs distribution derived from FNPP (137Cs-FK) within the whole trees contaminated directly. We examined concentrations and amounts of 137Cs-GFO in surface soils (0-5, 5-15 and 15-30 cm in depth) of 3470 samples at 316 sites all over Japan, which were collected just before the accident of FNPP. We determined 137Cs-GFO activities by NaI well-type scintillation counter with its accuracy verified using measurements by a germanium detector. We divided 316 sampling sites into 10 groups separated by one longitudinal line and four transversal lines on the terrain of Japan islands, then analyzed rainfall and geomorphological effects on 137Cs-GFO inventories. In addition to this dataset, we collected three whole tree samples of 26 year-old Quercus serrata at a contaminated area by FNPP accident in April, 2014 and examined concentrations of 137Cs-FK of above- and belowground tree parts by a germanium detector. We estimated an average of 137Cs-GFO inventories of forest soils in Japan to be 1.7 ± 1.4 kBq m-2 as of 2008. 137Cs-GFO inventories varied largely from 0-7.9 kBq m-2 among the country and accumulated greater in the north-western part along the Sea of Japan side. We detected rainfall effect on 137Cs-GFO inventories, which were greater where winter rainfall was large. As for vertical distribution of 137Cs-GFO, 44% of 137Cs-GFO remained within the uppermost 5 cm of soil profiles whereas the rest of 56% existed in 5-30 cm in depth. This indicated that considerable downward migration of 137Cs-GFO has happened during these fifty years in forest soils in Japan. However, multiple linear regression analysis by geomorphological factors related to soil

  9. Processing of analogues of plume fallout in cold regions of Enceladus by energetic electrons

    NASA Astrophysics Data System (ADS)

    Bergantini, A.; Pilling, S.; Nair, B. G.; Mason, N. J.; Fraser, H. J.

    2014-10-01

    Context. Enceladus, a small icy moon of Saturn, is one of the most remarkable bodies in the solar system. This moon is a geologically active object, and despite the lower temperatures on most of its surface, the geothermally heated south polar region presents geysers that spouts a plume made of water (~90%), carbon dioxide, methane, ammonia, and methanol, among other molecules. Most of the upward-moving particles do not have the velocity to escape from the gravitational influence of the moon and fall back to the surface. The molecules in the ice are continuously exposed to ionizing radiation, such as UV and X-rays photons, cosmic rays, and electrons. Over time, the ionizing radiation promotes molecular bond rupture, destroying and also forming molecules, radicals, and fragments. Aims: We analyse the processing of an ice mixture analogue to the Enceladus fallout ice in cold resurfaced areas (north pole) by 1 keV electrons. The main goal is to search for complex species that have not yet been detected in this moon, and to determine relevant physico-chemical parameters, such as destruction and formation cross-sections and the half-life of the studied molecules in the ice. Methods: The experiment consisted of the electron irradiation of an Enceladus-like ice mixture (H2O:CO2:CH4:NH3:CH3OH) in an ultra-high vacuum chamber at 20 K. The analysis was made by infrared spectrometry in the mid-infrared region (4000-800 cm-1 or 2.5-12.5 μm). Results: The absolute dissociation cross-sections of the parent molecules, the formation cross-section of daughter species, and the half-life of the parental species in a simulated Enceladus irradiation scenario were determined. Among the produced species, CO (carbon monoxide), OCN- (cyanate anion), HCONH2 (formamide), and H2CO (formaldehyde) were tentatively detected.

  10. Modeling the fallout from stabilized nuclear clouds using the HYSPLIT atmospheric dispersion model.

    PubMed

    Rolph, G D; Ngan, F; Draxler, R R

    2014-10-01

    The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, developed by the National Oceanic and Atmospheric Administration's Air Resources Laboratory, has been configured to simulate the dispersion and deposition of nuclear materials from a surface-based nuclear detonation using publicly available information on nuclear explosions. Much of the information was obtained from "The Effects of Nuclear Weapons" by Glasstone and Dolan (1977). The model was evaluated against the measurements of nuclear fallout from six nuclear tests conducted between 1951 and 1957 at the Nevada Test Site using the global NCEP/NCAR Reanalysis Project (NNRP) and the Weather Research and Forecasting (WRF) meteorological data as input. The model was able to reproduce the general direction and deposition patterns using the coarse NNRP data with Figure of Merit in Space (FMS - the percent overlap between predicted and measured deposition patterns) scores in excess of 50% for four of six simulations for the smallest dose rate contour, with FMS scores declining for higher dose rate contours. When WRF meteorological data were used the FMS scores were 5-20% higher in five of the six simulations, especially at the higher dose rate contours. The one WRF simulation where the scores declined slightly (10-30%) was also the best scoring simulation when using the NNRP data. When compared with measurements of dose rate and time of arrival from the Town Data Base (Thompson et al., 1994), similar results were found with the WRF simulations providing better results for four of six simulations. The overall result was that the different plume simulations using WRF data had more consistent performance than the plume simulations using NNRP data fields.

  11. Temporal trends in childhood leukaemia incidence following exposure to radioactive fallout from atmospheric nuclear weapons testing.

    PubMed

    Wakeford, Richard; Darby, Sarah C; Murphy, Michael F G

    2010-05-01

    Notably raised rates of childhood leukaemia incidence have been found near some nuclear installations, in particular Sellafield and Dounreay in the United Kingdom, but risk assessments have concluded that the radiation doses estimated to have been received by children or in utero as a result of operations at these installations are much too small to account for the reported increases in incidence. This has led to speculation that the risk of childhood leukaemia arising from internal exposure to radiation following the intake of radioactive material released from nuclear facilities has been substantially underestimated. The radionuclides discharged from many nuclear installations are similar to those released into the global environment by atmospheric nuclear weapons testing, which was at its height in the late-1950s and early-1960s. Measurements of anthropogenic radionuclides in members of the general public resident in the vicinity of Sellafield and Dounreay have found levels that do not differ greatly from those in persons living remote from nuclear installations that are due to ubiquitous exposure to the radioactive debris of nuclear weapons testing. Therefore, if the leukaemia risk to children resulting from deposition within the body of radioactive material discharged from nuclear facilities has been grossly underestimated, then a pronounced excess of childhood leukaemia would have been expected as a consequence of the short period of intense atmospheric weapons testing. We have examined childhood leukaemia incidence in 11 large-scale cancer registries in three continents for which data were available at least as early as 1962. We found no evidence of a wave of excess cases corresponding to the peak of radioactive fallout from atmospheric weapons testing. The absence of a discernible increase in the incidence of childhood leukaemia following the period of maximum exposure to the radioactive debris of this testing weighs heavily against the suggestion that

  12. Radioactive fallout cesium in sewage sludge ash produced after the Fukushima Daiichi nuclear accident.

    PubMed

    Kozai, Naofumi; Suzuki, Shinichi; Aoyagi, Noboru; Sakamoto, Fuminori; Ohnuki, Toshihiko

    2015-01-01

    The radioactive fallout cesium (¹³⁷Cs) in the sewage sludge ashes (SSAs) produced in Japan after the Fukushima Daiichi Nuclear Accident was tested. Five samples of SSAs produced in 2011 and 2012 were tested. Two of the samples contained ¹³⁷Cs (23 and 9.6 kBq/kg, respectively) above the radioactivity criterion (8 kBq of radioactive Cs/kg of solid) for controlled landfill disposal in Japan. The mineral components of SSA are roughly divided into two groups: an HCl-soluble phase mainly composed of phosphates and oxides; and silicates, including quartz, feldspar, and clay. Both phases contained ¹³⁷Cs. The majority (up to 90%) of ¹³⁷Cs was contained in the HCl-soluble phase. Among the HCl-soluble subphases, Fe-bearing phases that were probably iron oxides were mainly responsible for ¹³⁷Cs retention. No positive evidence was obtained that showed that phosphate-bearing phases, which were included most in SSAs along with the silicate phase, retained ¹³⁷Cs. Pre-pulverizing SSAs and heating them at 95 °C in a 6 M or a concentrated aqueous HCl was the most effective method of dissolving the HCl-soluble phase. The radioactivity concentrations of ¹³⁷Cs in all the HCl-treatment residues were below the radioactivity criterion. This residue was mostly composed of silicates. After static leaching tests of the residue at 60 °C for 28 days, no ¹³⁷Cs was detected in simulated environmental water leachates (pure water and synthetic seawater), demonstrating that 137Cs in the residue is very stably immobilized in the silicates.

  13. Estimation of radionuclide ingestion: Lessons from dose reconstruction for fallout from the Nevada Test Site

    SciTech Connect

    Breshears, D.D.; Whicker, F.W.; Kirchner, T.B.; Anspaugh, L.R.

    1994-09-01

    The United States conducted atmospheric testing of nuclear devices at the Nevada Test Site from 1951 through 1963. In 1979 the U.S. Department of Energy established the Off-Site Radiation Exposure Review Project to compile a data base related to health effects from nuclear testing and to reconstruct doses to public residing off of the Nevada Test Site. This project is the most comprehensive dose reconstruction project to date, and, since similar assessments are currently underway at several other locations within and outside the U.S., lessons from ORERP can be valuable. A major component of dose reconstruction is estimation of dose from radionuclide ingestion. The PATHWAY food-chain model was developed to estimate the amount of radionuclides ingested. For agricultural components of the human diet, PATHWAY predicts radionuclide concentrations and quantities ingested. To improve accuracy and model credibility, four components of model analysis were conducted: estimation of uncertainty in model predictions, estimation of sensitivity of model predictions to input parameters, and testing of model predictions against independent data (validation), and comparing predictions from PATHWAY with those from other models. These results identified strengths and weaknesses in the model and aided in establishing the confidence associated with model prediction, which is a critical component risk assessment and dose reconstruction. For fallout from the Nevada Test Site, by far, the largest internal doses were received by the thyroid. However, the predicted number of fatal cancers from ingestion dose was generally much smaller than the number predicted from external dose. The number of fatal cancers predicted from ingestion dose was also orders of magnitude below the normal projected cancer rate. Several lessons were learned during the study that are relevant to other dose reconstruction efforts.

  14. Medical status of Marshallese accidentally exposed to 1954 Bravo fallout radiation: January 1988 through December 1991

    SciTech Connect

    Howard, J.E.; Heotis, P.M.; Scott, W.A.; Adams, W.H.

    1995-07-01

    The purpose of this report is to disseminate information concerning the medical status of 253 Marshallese exposed to fallout radiation in 1954. This report discusses the medical care provided and the medical findings for the years 1988-1991. Details of the BRAVO thermonuclear accident that caused the exposure have been published, and a 1955 article in the Journal of the American Medical Association describing the acute medical effects in the exposed population remains a definitive and relevant description of events. Participation in the Marshall Islands Medical Program by the exposed Marshallese is voluntary. In the spring and fall of each year, medical surveillance is provided to exposed and unexposed cohorts. Examinations performed include: a cancer-related examination as defined by the American Society, an annual thyroid examination and thyroid function testing, serum prolactin testing looking for pituitary tumors, annual blood counts to include platelets, and evaluation for paraneoplastic evidence of neoplasms. This report details the medical program, medical findings, and thyroid surgery findings. Deaths (4 exposed and 10 nonexposed) that occurred during the reporting period are discussed. There is a mild but relatively consistent depression of neutrophil, lymphocyte, and platelet concentrations in the blood of the exposed population. This depression appears to be of no clinical significance. Thyroid hypofunction, either clinical or biochemical, has been documented as a consequence of radiation exposure in 14 exposed individuals. Previously, one other exposed person was diagnosed with basal cell carcinoma. During this reporting period, a thyroid nodule was identified in an individual who was in utero during the exposure. Upon pathologic review, the nodule was diagnosed as occult papillary carcinoma.

  15. Distribution of global fallouts cesium-137 in taiga and tundra catenae at the Ob River basin

    NASA Astrophysics Data System (ADS)

    Semenkov, I. N.; Usacheva, A. A.; Miroshnikov, A. Yu.

    2015-03-01

    The classification of soil catenae at the Ob River basin is developed and applied. This classification reflects the diverse geochemical conditions that led to the formation of certain soil bodies, their combinations and the migration fields of chemical elements. The soil and geochemical diversity of the Ob River basin catenae was analyzed. The vertical and lateral distribution of global fallouts cesium-137 was studied using the example of the four most common catenae types in Western Siberia tundra and taiga. In landscapes of dwarf birches and dark coniferous forests on gleysols, cryosols, podzols, and cryic-stagnosols, the highest 137Cs activity density and specific activity are characteristic of the upper soil layer of over 30% ash, while the moss-grass-shrub cover is characterized by low 137Cs activity density and specific activity. In landscapes of dwarf birches and pine woods on podzols, the maximum specific activity of cesium-137 is typical for moss-grass-shrub cover, while the maximum reserves are concentrated in the upper soil layer of over 30% ash. Bog landscapes and moss-grass-shrub cover are characterized by a minimum activity of 137Cs, and its reserves in soil generally decrease exponentially with depth. The cesium-137 penetration depth increases in oligotrophic histosols from northern to middle taiga landscapes from 10-15 to 40 cm. 137Cs is accumulated in oligotrophic histosols for increases in pH from 3.3 to 4.0 and in concretionary interlayers of pisoplinthic-cryic-histic-stagnosols. Cryogenic movement, on the one hand, leads to burying organic layers enriched in 137Cs and, on the other hand, to deducing specific activity when mixed with low-active material from lower soil layers.

  16. The risk of leukaemia in young children from exposure to tritium and carbon-14 in the discharges of German nuclear power stations and in the fallout from atmospheric nuclear weapons testing.

    PubMed

    Wakeford, Richard

    2014-05-01

    Towards the end of 2007, the results were published from a case-control study (the "KiKK Study") of cancer in young children, diagnosed <5 years of age during 1980-2003 while resident near nuclear power stations in western Germany. The study found a tendency for cases of leukaemia to live closer to the nearest nuclear power station than their matched controls, producing an odds ratio that was raised to a statistically significant extent for residence within 5 km of a nuclear power station. The findings of the study received much publicity, but a detailed radiological risk assessment demonstrated that the radiation doses received by young children from discharges of radioactive material from the nuclear reactors were much lower than those received from natural background radiation and far too small to be responsible for the statistical association reported in the KiKK Study. This has led to speculation that conventional radiological risk assessments have grossly underestimated the risk of leukaemia in young children posed by exposure to man-made radionuclides, and particular attention has been drawn to the possible role of tritium and carbon-14 discharges in this supposedly severe underestimation of risk. Both (3)H and (14)C are generated naturally in the upper atmosphere, and substantial increases in these radionuclides in the environment occurred as a result of their production by atmospheric testing of nuclear weapons during the late 1950s and early 1960s. If the leukaemogenic effect of these radionuclides has been seriously underestimated to the degree necessary to explain the KiKK Study findings, then a pronounced increase in the worldwide incidence of leukaemia among young children should have followed the notably elevated exposure to (3)H and (14)C from nuclear weapons testing fallout. To investigate this hypothesis, the time series of incidence rates of leukaemia among young children <5 years of age at diagnosis has been examined from ten cancer registries

  17. Testing fine sediment connectivity hypotheses using fallout radionuclide tracers in a small catchment with badlands. Vallcebre Research Catchments (NE Spain)

    NASA Astrophysics Data System (ADS)

    Gallart, Francesc; Latron, Jérôme; Vuolo, Diego; Martínez-Carreras, Núria; Pérez-Gallego, Nuria; Ferrer, Laura; Estrany, Joan

    2016-04-01

    In the Vallcebre Research Catchments (NE Spain), results obtained during over 20 years showed that badlands are the primary sources of sediments to the drainage network. Parent lutitic rocks are weathered during winter producing regoliths, which are eroded from badland surfaces mainly during summer intense rainstorms. Even if the produced sediments are mainly fine, due to the ephemeral nature of summer runoff events most of them are deposited on the stream beds, where they may remain during some time (months to years). Within the MEDhyCON project, a fallout radionuclides (FRNs) tracing experiment (i.e., excess lead 210 (Pbx-210) and beryllium 7 (Be-7)) is being carried out in order to investigate sediment connectivity. A simplified Pbx-210 balance model on badland surfaces suggested a seasonal sawtooth-like activity pattern: FRN being accumulated in regoliths from October to June and depleted in summer. Early summer erosion events would produce the sediments with the highest activity whereas late summer events would produce sediments with the lowest activity coming from the deeper regolith horizons. These findings lead us to launch two sediment transfer connectivity hypotheses analysing respectively the temporal and spatial variability of the Pb-210 activities within the fine sediments at the small catchment scale: (1) The temporal variability of suspended sediment activities at the gauging stations is a measure of sediment transfer immediacy, ergo connectivity. Hence, a high variability in suspended sediment activities, mimicking regolith activity temporal pattern would indicate high connectivity, whereas a low variability, meaning that sediments are mostly pooled in a large and slowly moving stock, would indicate low connectivity. (2) In a drainage system where fine sediments temporarily remain on the dry stream bed, the ratio between fine sediment activities at the sources and fine in-stream sediment activities downstream is a measure of sediment connectivity

  18. Atomic arias

    NASA Astrophysics Data System (ADS)

    Crease, Robert P.

    2009-01-01

    The American composer John Adams uses opera to dramatize controversial current events. His 1987 work Nixon in China was about the landmark meeting in 1972 between US President Richard Nixon and Chairman Mao Zedong of China; The Death of Klinghoffer (1991) was a musical re-enactment of an incident in 1985 when Palestinian terrorists kidnapped and murdered a wheelchair-bound Jewish tourist on a cruise ship. Adams's latest opera, Doctor Atomic, is also tied to a controversial event: the first atomic-bomb test in Alamogordo, New Mexico, on 16 June 1945. The opera premièred in San Francisco in 2005, had a highly publicized debut at the Metropolitan Opera in New York in 2008, and will have another debut on 25 February - with essentially the same cast - at the English National Opera in London.

  19. Atomic rivals

    SciTech Connect

    Goldschmidt, B.

    1990-01-01

    This book is a memoir of rivalries among the Allies over the bomb, by a participant and observer. Nuclear proliferation began in the uneasy wartime collaboration of the United States, England, Canada, and Free France to produce the atom bomb. Through the changes of history, a young French chemist had a role in almost every act of this international drama. This memoir is based on Goldschmidt's own recollections, interviews with other leading figures, and 3,000 pages of newly declassified documents in Allied archives. From his own start as Marie Curie's lab assistant, Goldschmidt's career was closely intertwined with Frances complicated rise to membership in the nuclear club. As a refugee from the Nazis, he became part of the wartime nuclear energy project in Canada and found himself the only French scientist to work (although briefly) on the American atom bomb project.

  20. Atomic physics

    SciTech Connect

    Livingston, A.E.; Kukla, K.; Cheng, S.

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  1. Atomic Databases

    NASA Astrophysics Data System (ADS)

    Mendoza, Claudio

    2000-10-01

    Atomic and molecular data are required in a variety of fields ranging from the traditional astronomy, atmospherics and fusion research to fast growing technologies such as lasers, lighting, low-temperature plasmas, plasma assisted etching and radiotherapy. In this context, there are some research groups, both theoretical and experimental, scattered round the world that attend to most of this data demand, but the implementation of atomic databases has grown independently out of sheer necessity. In some cases the latter has been associated with the data production process or with data centers involved in data collection and evaluation; but sometimes it has been the result of individual initiatives that have been quite successful. In any case, the development and maintenance of atomic databases call for a number of skills and an entrepreneurial spirit that are not usually associated with most physics researchers. In the present report we present some of the highlights in this area in the past five years and discuss what we think are some of the main issues that have to be addressed.

  2. Can 239 + 240Pu replace 137Cs as an erosion tracer in agricultural landscapes contaminated with Chernobyl fallout?

    PubMed

    Schimmack, W; Auerswald, K; Bunzl, K

    2001-01-01

    Erosion studies often use 137Cs from the global fallout (main period: 1953-1964) as a tracer in the soil. In many European countries, where 137Cs was deposited in considerable amounts also by the Chernobyl fallout in 1986, the global fallout fraction (GF-Cs) has to be separated from the Chernobyl fraction by means of the isotope 134Cs. In a few years, this will no longer be possible due to the short half-life of 134Cs (2 yr). Because GF-Cs in the soil can then no longer be determined, the potential of using 239 + 240Pu as a tracer is evaluated. This radionuclide originates in most European countries essentially only from the global fallout. The activities and spatial distributions of Pu and GF-Cs were compared in the soil of a steep field (inclination about 20%, area ca. 3 ha, main soil type Dystric Eutrochrept), sampled at 48 nodes of a 25 x 25 m2 grid. The reference values were determined at 12 points adjacent to the field. Their validity was assured by an inventory study of radiocaesium in a 70 ha area surrounding the field sampling 275 nodes of a 50 x 50 m2 grid. In the field studied, the activity concentrations of GF-Cs and Pu in the Ap horizon were not correlated (Spearman correlation coefficient R = 0.20, p > 0.05), and the activity balance of Pu differed from that of GF-Cs. Whereas no net loss of GF-Cs from the field was observed as compared to the reference site, Pu was more mobile with an average loss of ca. 11% per unit area. In addition, the spatial pattern of GF-Cs and Pu in the field differed significantly. The reason may be that due to their different associations with soil constituents, Pu and Cs represent different fractions of the soil, exhibiting different properties with respect to erosion/deposition processes. This indicates that both radionuclides or one of them may not be appropriate to quantity past erosion. When tracer losses are used to calibrate or verify erosion prediction models, systematic deviations may not only stem from model

  3. Use of Lasers to Study the Impact of Fractionation and Condensation on the Toxicity of Nuclear Weapon Fallout

    SciTech Connect

    Vidnovic III, T; Bradley, K S; Debonnel, C S; Dipeso, G; Fournier, K; Karpenko, V P; Tobin, M

    2005-04-01

    An experimental concept has been developed to collect data to aid in the refinement of simulation programs designed to predict the fallout effects arising from surface and shallowly buried nuclear weapon detonations. These experiments, called the Condensation Debris Experiments (CDE), are intended to study the condensation/fractionation of material that is liberated following an initial deposition of laser energy onto a small, characterized target. The CDE effort also encompasses target development and material studies as well as supporting computational efforts studying radiation hydrodynamics, computational fluid dynamics, and relevant neutron activation processes (not discussed here).

  4. Calculated nuclide compositions and gamma-ray exposure rates for fallout from the HARRY, SMOKY, and ANNIE events

    SciTech Connect

    Hicks, H.G.

    1981-03-03

    The results of computer calculations of the nuclide composition and associated external gamma-ray exposure rates for fallout from the HARRY, SMOKY, and ANNIE events are documented. The fission product distribution is calculated for each event with the appropriate neutron spectrum and the fractions of fissions due to each fissionable material. Also calculated are the total number of microcuries per square meter and the gamma-ray exposure rates (mR/h, 1 meter above ground level) for the 152 fission products and 25 neutron-induced nuclides. The normalized data are presented in 9 Appendices. (DLS)

  5. GPR investigation of tephra fallout, Cerro Negro volcano, Nicaragua: a method for constraining parameters used in tephra sedimentation models

    NASA Astrophysics Data System (ADS)

    Courtland, L. M.; Kruse, S. E.; Connor, C. B.; Connor, L. J.; Savov, I. P.; Martin, K. T.

    2012-08-01

    Most tephra fallout models rely on the advection-diffusion equation to forecast sedimentation and hence volcanic hazards. Here, we test the application of the advection-diffusion equation to tephra sedimentation using data collected on the proximal (350 to ~1,200 m from the vent) to medial (greater than ~1,200 m from the vent) tephra blanket of a basaltic cinder cone, Cerro Negro volcano, located in Nicaragua. Our understanding of tephra depositional processes at this volcano is significantly improved by combination of sample pit data in the medial zone and high-resolution ground-penetrating radar (GPR) data collected in the near vent and proximal zones. If the advection-diffusion equation applies, then the thickness of individual tephra deposits should have Gaussian crosswind profiles and exponential decay with distance away from the vent. At Cerro Negro, steady trade winds coupled with brief eruptions of relatively low energy (VEI 2-3) create relatively simple deposits. GPR data were collected along three crosswind profiles at distances of 700-1,600 m from the vent; sample pits were used to estimate thickness of the 1992 tephra deposit up to 13 km from the vent. Horizons identified in proximal GPR profiles exhibit Gaussian distributions with a high degree of statistical confidence, with diffusion coefficients of ~500 m2 s-1 estimated for the deposits, confirming that the advection-diffusion equation is capable of modeling sedimentation in the proximal zone. The thinning trend downwind of the vent decreases exponentially from the cone base (350 m) to ~1,200 m from the vent. Beyond this distance, deposit overthickening occurs, identified in both GPR and sample pit datasets. The combined data reveal three depositional regimes: (1) a near-vent region on the cone itself, where fallout remobilizes in granular flows upon deposition; (2) a proximal zone in which particles fall from a height of less than ~2 km; and (3) a medial zone, in which particles fall from ~4 to 7

  6. The "AQUASCOPE" simplified model for predicting 89,90Sr, 131I, and 134,137Cs in surface waters after a large-scale radioactive fallout.

    PubMed

    Smith, J T; Belova, N V; Bulgakov, A A; Comans, R N J; Konoplev, A V; Kudelsky, A V; Madruga, M J; Voitsekhovitch, O V; Zibold, G

    2005-12-01

    Simplified dynamic models have been developed for predicting the concentrations of radiocesium, radiostrontium, and I in surface waters and freshwater fish following a large-scale radioactive fallout. The models are intended to give averaged estimates for radionuclides in water bodies and in fish for all times after a radioactive fallout event. The models are parameterized using empirical data collected for many lakes and rivers in Belarus, Russia, Ukraine, UK, Finland, Italy, The Netherlands, and Germany. These measurements span a long time period after fallout from atmospheric nuclear weapons testing and following the Chernobyl accident. The models thus developed were tested against independent measurements from the Kiev Reservoir and Chernobyl Cooling Pond (Ukraine) and the Sozh River (Belarus) after the Chernobyl accident, from Lake Uruskul (Russia), following the Kyshtym accident in 1957, and from Haweswater Reservoir (UK), following atmospheric nuclear weapons testing. The AQUASCOPE models (implemented in EXCEL spreadsheets) and model documentation are available free of charge from the corresponding author.

  7. Measuring fallout radionuclides to constrain the origin and the dynamics of suspended sediment in an agricultural drained catchment (Loire River basin, France)

    NASA Astrophysics Data System (ADS)

    Le Gall, Marion; Evrard, Olivier; Foucher, Anthony; Laceby, J. Patrick; Salvador-Blanes, Sébastien; Lefèvre, Irène; Cerdan, Olivier; Ayrault, Sophie

    2015-04-01

    Soil erosion reaches problematic levels in agricultural areas of Northwestern Europe where tile drains may accelerate sediment transfer to rivers. This supply of large quantities of fine sediment to the river network leads to the degradation of water quality by increasing water turbidity, filling reservoirs and transporting contaminants. Agricultural patterns and landscapes features have been largely modified by human activities during the last century. To investigate erosion and sediment transport in lowland drained areas, a small catchment, the Louroux (24 km²), located in the French Loire River basin was selected. In this catchment, channels have been reshaped and more than 220 tile drains outlets have been installed after World War II. As a result, soil erosion and sediment fluxes strongly increased. Sediment supply needs to be better understood by quantifying the contribution of sources and the residence times of particles within the catchment. To this end, a network of river monitoring stations was installed, and fallout radionuclides (Cs-137, excess Pb-210 and Be-7) were measured in rainwater (n=3), drain tile outlets (n=4), suspended sediment (n=15), soil surface (n=30) and channel bank samples (n=15) between January 2013 and February 2014. Cs-137 concentrations were used to quantify the contribution of surface vs. subsurface sources of sediment. Results show a clear dominance of particles originating from surface sources (99 ± 1%). Be-7 and excess Pb-210 concentrations and calculation of Be-7/excess Pb-210 ratios in rainfall and suspended sediment samples were used to estimate percentages of recently eroded sediment in rivers. The first erosive winter storm mainly exported sediment depleted in Be-7 that likely deposited on the riverbed during the previous months. Then, during the subsequent floods, sediment was directly eroded and exported to the catchment outlet. Our results show the added value of combining spatial and temporal tracers to characterize

  8. Atomization and mixing study

    NASA Technical Reports Server (NTRS)

    Ferrenberg, A.; Jaqua, V. W.

    1983-01-01

    The state of the art in atomization and mixing for triplet, pentad, and coaxial injectors is described. Injectors that are applicable for LOX/hydrocarbon propellants and main chamber and fuel rich preburner/gas generator mixture ratios are of special interest. Various applicable correlating equations and parameters as well as test data found in the literature are presented. The validity, utility, and important aspects of these data and correlations are discussed and the measurement techniques used are evaluated. Propellant mixing tests performed are described and summarized, results are reported, and tentative conclusions are included.

  9. Estimates of the cancer burden in Europe from radioactive fallout from the Chernobyl accident.

    PubMed

    Cardis, Elisabeth; Krewski, Daniel; Boniol, Mathieu; Drozdovitch, Vladimir; Darby, Sarah C; Gilbert, Ethel S; Akiba, Suminori; Benichou, Jacques; Ferlay, Jacques; Gandini, Sara; Hill, Catherine; Howe, Geoffrey; Kesminiene, Ausrele; Moser, Mirjana; Sanchez, Marie; Storm, Hans; Voisin, Laurent; Boyle, Peter

    2006-09-15

    The Chernobyl accident, which occurred April 26, 1986, resulted in a large release of radionuclides, which were deposited over a very wide area, particularly in Europe. Although an increased risk of thyroid cancer in exposed children has been clearly demonstrated in the most contaminated regions, the impact of the accident on the risk of other cancers as well as elsewhere in Europe is less clear. The objective of the present study was to evaluate the human cancer burden in Europe as a whole from radioactive fallout from the accident. Average country- and region-specific whole-body and thyroid doses from Chernobyl were estimated using new dosimetric models and radiological data. Numbers of cancer cases and deaths possibly attributable to radiation from Chernobyl were estimated, applying state-of-the-art risk models derived from studies of other irradiated populations. Simultaneously, trends in cancer incidence and mortality were examined over time and by dose level. The risk projections suggest that by now Chernobyl may have caused about 1,000 cases of thyroid cancer and 4,000 cases of other cancers in Europe, representing about 0.01% of all incident cancers since the accident. Models predict that by 2065 about 16,000 (95% UI 3,400-72,000) cases of thyroid cancer and 25,000 (95% UI 11,000-59,000) cases of other cancers may be expected due to radiation from the accident, whereas several hundred million cancer cases are expected from other causes. Although these estimates are subject to considerable uncertainty, they provide an indication of the order of magnitude of the possible impact of the Chernobyl accident. It is unlikely that the cancer burden from the largest radiological accident to date could be detected by monitoring national cancer statistics. Indeed, results of analyses of time trends in cancer incidence and mortality in Europe do not, at present, indicate any increase in cancer rates -- other than of thyroid cancer in the most contaminated regions

  10. Understanding Polycyclic Aromatic Hydrocarbon transfers at the catchment scale combining chemical and fallout radionuclides analyses

    NASA Astrophysics Data System (ADS)

    Gateuille, David; Evrard, Olivier; Lefevre, Irène; Moreau-Guigon, Elodie; Alliot, fabrice; Chevreuil, Marc; Mouchel, Jean-Marie

    2013-04-01

    Contamination of river water and sediment constitutes a major environmental issue for industrialized countries. Polycyclic Aromatic Hydrocarbons (PAHs) are a group of persistent organic pollutants characterized by two or more fused rings. In recent years, studies dealing with PAHs have grown in number. Some PAHs present indeed a high risk for environment and human health because of their carcinogenic and mutagenic properties. However, most of these studies focused on measuring PAH concentration in the different compartments of the environment (air, soil, sediment, water, etc.) In this context, there remains a lack of understanding regarding the various processes responsible for PAH transfers from one environmental compartment to another. Our study aims to quantify PAHs transfers at the catchment scale by combining chemical analysis with gamma spectrometry. Air, soil, river water and sediment samples (n=820) were collected in two upstream sub-catchments of the Seine River basin (France) during one year. Chemical analyses were carried out to determine PAHs concentrations in all samples. Furthermore, measurement of fallout radionuclides (Beryllium-7, Lead-210, Caesium-137) in both rainfall and river sediment provided a way to discriminate between freshly eroded sediment vs. resuspension of older material that previously deposited on the riverbed. This information is crucial to estimate PAH residence time and transfer velocities in the Seine River basin. The results show that the PAH behaviour varies from one subcatchment to the next. PAH transfers depend indeed on both the characteristics of the catchment (e.g. topography, presence of drained cropland in catchments) and the local anthropogenic pressures. A significant increase in atmospheric deposition of PAHs is observed during winter due to a larger number of sources (household heating). The 14-month study has also highlighted the seasonal variations of PAH fluxes, which are mainly related to the hydrological

  11. The Atomic and Nuclear Physics of Atomic EDMs

    NASA Astrophysics Data System (ADS)

    Chupp, Timothy

    2016-09-01

    Atomic Electric-Dipole-Moment (EDM) measurements employ low-energy atomic and precision-measurement techniques to measure the effects of elementary particle forces that affect the distribution of charge and mass in the nucleus, which is probed by the atomic electrons. Experiments and their interpretation strongly overlap atomic and nuclear physics in the experimental and theoretical problems presented. On the experimental side, the atomic EDM couples to electric fields while the magnetic dipole moment couples to magnetic fields requiring exquisite control and characerization of the magnetic fields. Measuring the tiny frequency shifts requires clock-comparisons and a large signal-to-noise ratio for frequency resolution much smaller than the linewidths, which are lmitied by observation times. To address the experimental challenges, I will discuss systematic effects related to magnetic fields and techniques of magnetometry and co-magntometery as well as optical pumping and related techniques that enhance signal-to-noise. I will also address the interpretation of atomic EDMs in terms of a set of low-energy parameters that relate to effective-field-theory coefficients, and I will empshaize the need for improved calculations from both atomic-theory and nuclear theory.

  12. Fallout plutonium and natural radionuclides in annual bands of the coral Montastrea annularis, St. Croix, U. S. Virgin Islands

    SciTech Connect

    Benninger, L.K.; Dodge, R.E.

    1986-12-01

    The authors have investigated the banded coral Montastrea annularis as a recorder of the history of fallout Pu in surface seawater. To aid the Pu interpretation Ca, Mg, Sr, Na and natural radionuclides (/sup 238/U, /sup 228/Ra, /sup 232/Th and /sup 210/Pb) were also determined in the annual bands. In small samples (0.5 g) Ca, Mg and Na show correlated variations which could be due to seasonal variability in uptake. The /sup 238/U and /sup 228/Ra records were generally consistent with uptake, at constant discrimination, from surface-water reservoirs of nearly constant concentration, although one sample showed probable diagenetic addition of U. /sup 232/Th was not detected with certainty; this implies that terrigenous particles were not consistently entrapped within the coral skeleton. Interpretation of /sup 210/Pb was difficult because /sup 226/Ra was not measured. Montastrea annularis preserves a record of fallout Pu. To make this record useful it must be considered in the broadest possible geochemical context.

  13. Relationship between volcanic ash fallouts and seismic tremor: quantitative assessment of the 2015 eruptive period at Cotopaxi volcano, Ecuador

    NASA Astrophysics Data System (ADS)

    Bernard, Benjamin; Battaglia, Jean; Proaño, Antonio; Hidalgo, Silvana; Vásconez, Francisco; Hernandez, Stephen; Ruiz, Mario

    2016-11-01

    Understanding the relationships between geophysical signals and volcanic products is critical to improving real-time volcanic hazard assessment. Thanks to high-frequency sampling campaigns of ash fallouts (15 campaigns, 461 samples), the 2015 Cotopaxi eruption is an outstanding candidate for quantitatively comparing the amplitude of seismic tremor with the amount of ash emitted. This eruption emitted a total of 1.2E + 9 kg of ash ( 8.6E + 5 m3) during four distinct phases, with masses ranging from 3.5E + 7 to 7.7E + 8 kg of ash. We compare the ash fallout mass and the corresponding cumulative quadratic median amplitude of the seismic tremor and find excellent correlations when the dataset is divided by eruptive phase. We use scaling factors based on the individual correlations to reconstruct the eruptive process and to extract synthetic Eruption Source Parameters (daily mass of ash, mass eruption rate, and column height) from the seismic records. We hypothesize that the change in scaling factor through time, associated with a decrease in seismic amplitudes compared to ash emissions, is the result of a more efficient fragmentation and transport process. These results open the possibility of feeding numerical models with continuous geophysical data, after adequate calibration, in order to better characterize volcanic hazards during explosive eruptions.

  14. Atom Skimmers and Atom Lasers Utilizing Them

    NASA Technical Reports Server (NTRS)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  15. Design procedure for effervescent atomizers

    NASA Astrophysics Data System (ADS)

    Chin, J. S.; Lefebvre, A. H.

    1995-04-01

    A methodology for the design of effervescent atomizers is described. The objective is to achieve sprays of minimum mean drop size for any stipulated values of liquid flow rate, air supply pressure, and air/liquid ratio. Application of the method leads to optimum values for all the key atomizer dimensions, including the number and size of the air injection holes, and the diameters of the mixing chamber and discharge orifice. It also enables optimum dimensions to be determined for a convergent-divergent nozzle should such a device be fitted to the nozzle exit to improve atomization performance. Examples are provided to demonstrate the application of the recommended design procedure and to illustrate the relative importance of various flow and geometric parameters in regard to their effects on atomization quality.

  16. High Atom Number in Microsized Atom Traps

    DTIC Science & Technology

    2015-12-14

    cooling of some atoms in atomic beam. We have reconfigured the apparatus for applying bichromatic forces transverse to the atomic beam, as it will be...apparatus for applying bichromatic forces transverse to the atomic beam, as it will be easier to extend this to two dimensions. Research to develop

  17. Atomic magnetometer

    DOEpatents

    Schwindt, Peter [Albuquerque, NM; Johnson, Cort N [Albuquerque, NM

    2012-07-03

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  18. Distribution and Ratios of 137Cs and K in Control and K-treated Coconut Trees at Bikini Island where Nuclear Test Fallout Occurred: Effects and Implications

    SciTech Connect

    Robison, W L; Brown, P H; Stone, E L; Hamilton, T F; Conrado, C L; Kehl, S R

    2008-05-19

    Coconut trees growing on atolls of the Bikini Islands are on the margin of K deficiency because the concentration of exchangeable K in coral soil is very low ranging from only 20 to 80 mg kg{sup -1}. When provided with additional K, coconut trees absorb large quantities of K and this uptake of K significantly alters the patterns of distribution of {sup 137}Cs within the plant. Following a single K fertilization event, mean total K in trunks of K-treated trees is 5.6 times greater than in trunks of control trees. In contrast, {sup 137}Cs concentration in trunks of K-treated and control trees is statistically the same while {sup 137}Cs is significantly lower in edible fruits of K treated trees. Within one year after fertilization (one rainy season), K concentration in soil is back to naturally, low concentrations, however, the tissue concentrations of K in treated trees stays very high internally in the trees for years while {sup 137}Cs concentration in treated trees remains very low in all tree compartments except for the trunk. Potassium fertilization did not change soil Cs availability. Mass balance calculations suggest that the fertilization event increased above ground plant K content by at least a factor of 5 or 2.2 kg. Potassium concentrations and content were higher in all organs of K fertilized trees with the greatest increases seen in organs that receive a portion of tissue K through xylem transport (trunk, fronds and fruit husks) and lowest in organs supplied predominantly with K via the phloem (palm heart, spathe, coco meat and fluid). {sup 137}Cesium concentrations and contents were dramatically lower in all organs of K treated trees with greatest proportional reductions observed in organs supplied predominantly with K via the phloem (palm heart, spathe, coco meat and fluid). All trees remobilize both K and {sup 137}Cs from fronds as they proceed toward senescence. In control trees the reduction in concentration of K and {sup 137}Cs in fronds as they age is logarithmic but K remobilization is linear in K-treated trees where K concentration is high. As a result of K treatment the {sup 137}Cs concentration in K-treated fronds is extremely low and constant with frond age. Fronds of K treated trees contain a greater amount of K than control tree fronds. As they fall to the ground and decay they provide a small continuing pool of K that is about 3% of the natural K in soil under the tree canopy. Results of K and {sup 137}Cs concentration and distribution in control and K-treated coconut trees suggest that the application of K reduces {sup 137}Cs uptake both in the short term immediately following K fertilization and in the long term, after soil K levels have returned to normal but while plant K stores remain high. These results suggests that high internal K concentration and not high soil K is primarily responsible for long-term reduction of {sup 137}Cs in edible fruits, and plays a significant role in limiting further uptake of {sup 137}Cs by roots, and affects allocation of {sup 137}Cs to edible fruits for years. Coconut trees are capable of luxury K accumulation when provided with excess K and in this example the additional K can effectively provide the K requirements of the plant for in excess of 10 years. The reduction of {sup 137}Cs uptake lasts for at least 10 y after K is last applied and greatly reduces the estimated radiation dose to people consuming local tree foods. Effectiveness and duration of K treatment provides important assurances that reduction in {sup 137}Cs is long term and the radiation dose from consuming local plant foods will remain low.

  19. Distribution and ratios of 137Cs and K in control and K-treated coconut trees at Bikini Island where nuclear test fallout occurred: effects and implications.

    PubMed

    Robison, William L; Brown, Patrick H; Stone, Earl L; Hamilton, Terry F; Conrado, Cynthia L; Kehl, Steven

    2009-01-01

    Coconut trees growing on atolls of the Bikini Islands are on the margin of K deficiency because the concentration of exchangeable K in coral soil is very low, ranging from only 20 to 80mgkg(-1). When provided with additional K, coconut trees absorb large quantities of K and this uptake of K significantly alters the patterns of distribution of 137Cs within the plant. Following a single K fertilization event, mean total K in trunks of K-treated trees is 5.6 times greater than in trunks of control trees. In contrast, 137Cs concentration in trunks of K-treated and control trees is statistically the same while 137Cs is significantly lower in edible fruits of K-treated trees. Within one year after fertilization (one rainy season), K concentration in soil is back to naturally low concentrations. However, the tissue concentrations of K in treated trees stays very high internally in the trees for years while 137Cs concentration in treated trees remains very low in all tree compartments except for the trunk. Potassium fertilization did not change soil Cs availability. Mass balance calculations suggest that the fertilization event increased above ground plant K content by at least a factor of 5 (2.2kg). Potassium concentrations and content were higher in all organs of K-fertilized trees with the greatest increases seen in organs that receive a portion of tissue K through xylem transport (trunk, fronds and fruit husks) and lowest in organs supplied predominantly with K via the phloem (palm heart, spathe, coco meat and fluid). The 137Cesium concentrations and contents were dramatically lower in all organs of K-treated trees with greatest proportional reductions observed in organs supplied predominantly with K via the phloem (palm heart, spathe, coco meat and fluid). All trees remobilize both K and 137Cs from fronds as they proceed toward senescence. In control trees the reduction in concentration of K and 137Cs in fronds as they age is logarithmic, but K remobilization is linear in K-treated trees where K concentration is high. As a result of K treatment the 137Cs concentration in K-treated fronds is extremely low and constant with frond age. Fronds of K-treated trees contain a greater amount of K than control tree fronds. As they fall to the ground and decay they provide a small continuing pool of K that is about 3% of the natural K in soil under the tree canopy. Results of K and 137Cs concentration and distribution in control and K-treated coconut trees suggest that the application of K reduces 137Cs uptake both in the short term immediately following K fertilization and in the long term, after soil K levels have returned to normal but while plant K stores remain high. These results suggest that high internal K concentration and not high soil K is primarily responsible for long-term reduction of 137Cs in edible fruits, play a significant role in limiting further uptake of 137Cs by roots, and affects allocation of 137Cs to edible fruits for years. Coconut trees are capable of luxury K accumulation when provided with excess K and in this example the additional K can effectively provide the K requirements of the plant for in excess of 10y. The reduction of 137Cs uptake lasts for at least 10y after K is last applied and greatly reduces the estimated radiation dose to people consuming local tree foods. Effectiveness and duration of K treatment provide important assurances that reduction in 137Cs is long term and the radiation dose from consuming local plant foods will remain low.

  20. Ecological half-time and effective dose from chernobyl debris and from nuclear weapons fallout of 137Cs as measured in different Swedish populations.

    PubMed

    Rääf, C L; Hubbard, L; Falk, R; Agren, G; Vesanen, R

    2006-05-01

    The fallout in Sweden of radiocesium from nuclear weapons tests during the 1960's (137Cs) and from the Chernobyl accident in 1986 (134Cs and 137Cs) has transferred to humans through different ecological pathways. Data from whole-body burden measurements of 134Cs, 137Cs, and 40K in various Swedish populations between 1964 and 2002 have been compiled. This database enables an evaluation of the temporal and geographical dependence of the transfer of radiocesium from ground deposition to humans and the associated absorbed dose. The body burdens of 137Cs gradually decrease after the peak values reached in 1965 from nuclear weapons fallout and in 1987 from the Chernobyl fallout, but at a varying rate depending on the population. Assuming a dual exponential decrease, a short-term component of typically 1-2 y and a long-term component of 5-10 y are found in urban populations in Sweden. Among reindeer herders and hunters the effective ecological half-time is mono-exponential with a half-time of 5-7 y. The estimated time-integrated effective dose to an individual during a period of 50 y from the Chernobyl fallout is, on average, approximately 10 mSv for reindeer herders, which is 10-100 times higher than the estimated dose received by urban populations in the three major Swedish urban areas (Malmö, Göteborg, and Stockholm).

  1. Thermoluminescence measurements of gamma-ray doses attributable to fallout from the Nevada test site using building bricks as natural dosimeters

    SciTech Connect

    Haskell, E.H.; Kenner, G.H.; Bailiff, I.K.

    1994-04-01

    During the 1950`s, the U.S. Government conducted an intensive atmospheric nuclear testing program in Nevada. Fallout from these atmospheric tests was measured throughout the U.S. with some of the heaviest concentrations to populated areas falling east of the test site in Washington County, UT. External exposures from 6.5 x 10{sup -4} C kg{sup -1} to 26 x 10{sup -4} C kg{sup -1} (2.5-5.0 R) were reported for this region. This study provides an independent measurement of fallout radiation doses to selected communities in Utah using a thermoluminescence technique originally developed for the dating of ancient pottery. The application of the predose thermoluminescence technique to fallout dosimetry is described. A mean dose of 38 {+-} 15 mGy (4.4 {+-} 1.7 R), attributed to fallout radiation, was measured in quartz grains extracted from the outer centimeter of bricks removed from six communities in Washington and Kane Counties in Utah. 48 refs., 7 figs., 3 tabs.

  2. Long-term transfer of global fallout ¹³⁷Cs to cow's milk in Iceland.

    PubMed

    Pálsson, S E; Howard, B J; Gudnason, K; Sigurgeirsson, M A

    2012-12-01

    The aim of this study was to provide improved information on the long-term transfer of global nuclear weapons (137)Cs fallout to cow's milk in Iceland many years after deposition. The spatial variation in deposition was confirmed to be explained by precipitation. Soil samples showed a significant difference in (137)Cs deposition density between the main agricultural areas, with the South having the highest values, then the West and North and the lowest in the Northeast. There was no significant difference between the effective half-lives in (137)Cs activity concentrations in milk and milk powder from the main dairies in Iceland based on data for milk from 1990 to 2007 and for milk powder from 1986 to 2007. There was, however, a significant difference between the effective half-lives obtained for these two regions, 13.5 years for the Northern and 10.5 years for the Southern regions. These half-lives for global fallout are longer than those previously reported for similar time periods in other Arctic areas. The transfer of (137)Cs to cow's milk was quantified for different agricultural regions using aggregated transfer coefficients (T (ag)) for the period of peak global fallout soil inventory in 1965-1967. The values ranged from 2.8 × 10(-3) to 10.6 × 10(-3) m(2) kg(-1). By 2001-2004, the T (ag) values had only declined, in the main agricultural areas, to 0.6 × 10(-3)-1.0 × 10(-3) m(2) kg(-1). Long-term transfer rates to milk many years after deposition were high in Iceland compared with most other reported data. The transfer is potentially relevant for some of the contaminated areas around the Fukushima Nuclear Power Plant after the accident in March 2011 since limited information is available on uptake from Andosols and associated effective half-lives.

  3. The Golden Ratio

    ERIC Educational Resources Information Center

    Hyde, Hartley

    2004-01-01

    The Golden Ratio is sometimes called the "Golden Section" or the "Divine Proportion", in which three points: A, B, and C, divide a line in this proportion if AC/AB = AB/BC. "Donald in Mathmagicland" includes a section about the Golden Ratio and the ratios within a five-pointed star or pentagram. This article presents two computing exercises that…

  4. Collective State Raman Atomic Clock Using Trapped Atoms

    NASA Astrophysics Data System (ADS)

    Kim, May; Sarkar, Resham; Fang, Renpeng; Tu, Yanfei; Shahriar, Selim

    2014-05-01

    Atomic clock has set the standard as the most accurate clock in the world. So far, the approach to making the atomic clock has been limited to utilizing individual atomic states. We have developed the framework for a collective atomic clock-in an ensemble of cold atoms using the method of separated Raman-Ramsey fields-by conceiving a method to detect the collective states, analyzing the signal to noise ratio, and finding the bounds for efficiency of our detector. The width of the Raman-Ramsey fringe in such a clock is narrower than that of a conventional Raman-Ramsey fringe by a factor of root-N, where N is the number of atoms in the ensemble. When the collection efficiency of the detection process is taken into account, such a clock can have a frequency stability that is expected to be better than that of a conventional Raman-Ramsey clock. The ultra-narrow fringe may also offer many other potential advantages, such as suppression of errors due to fluctuations in the bias field used for lifting Zeeman sublevel degeneracy, and the long-term bias drift. We will present the theoretical model, and describe the status of our experimental efforts towards demonstrating such a clock.

  5. Establishment of the central radiation dose registration system for decontamination work involving radioactive fallout emitted by the Fukushima Daiichi APP accident.

    PubMed

    Yasui, Shojiro

    2016-10-01

    With respect to radiation protection for decontamination efforts involving radioactive fallout emitted by the accident at the Fukushima Daiichi Atomic Power Plant, new regulations were established and obligated employers to monitor, record, and store of workers' dose records, and to check their past dose records at the time of employment. However, cumulative doses may not be properly maintained if a worker declares incorrect values for past doses. In response, with facilitation from the Ministry of Health, Labour and Welfare, primary contractors of decontamination works decided to establish a central dose registration system. There are four major issues in the design of the system to be resolved, included the following: primary contractors (a) do not have a legal responsibility to perform dose control for subcontractors, (b) do not have the right to control decontamination sites, (c) often organize joint ventures, and (d) correspond to a wide range of ambient dose rates. To resolve the issues, requirements of the system included the following: (a) centralize the operation of radiation passbooks, which records past doses and the results of medical examinations to each worker; (b) develop a database system that could register all dose data and accept inquiry from primary contractors; (c) establish a permanent data storage system for transferred records; and (d) provide graded type of services that are appropriate to the risk of radiation exposure. The system started its operation in December 2013 and provided dose distributions in April and July 2015. The average yearly dose in 2014 was 0.7 mSv, which increased by 0.2 mSv from 0.5 mSv in 2012 and 2013. However, no cumulative dose from 2012-2014 exceeded 20 mSv, which was far below than the dose limits (100 mSv/5 years and 50 mSv/year). Although current dose distributions of decontamination workers were within appropriate levels, careful monitoring of dose distribution is necessary for preserving the proper

  6. A new generic sub-model for radionuclide fixation in large catchments from continuous and single-pulse fallouts, as used in a river model.

    PubMed

    Håkanson, Lars

    2004-01-01

    This paper presents a new general sub-model for fixation in catchment areas to be used within the framework of a river model for substances such as radionuclides and metals from continuous and single-pulse fallouts. The model has been critically tested using data from 27 European river sites covering a very wide geographical area and contaminated by radiocesium and radiostrontium from the Chernobyl accident and from the nuclear weapons tests (NWT fallout). This modelling approach gives radionuclide concentrations in water (total, dissolved and particulate phases) at defined sites on a monthly basis. The overall river model is based on processes in the upstream river stretch and in the catchment area. The catchment area is differentiated into inflow (approximately dry land) areas and outflow (approximately wetland) areas. The model has a general structure, which can be used for all radionuclides or substances. It is simple to apply in practice since all driving variables may be readily accessed from maps and standard monitoring programs. The driving variables are: latitude, altitude, catchment area, mean annual precipitation and fallout. Note that for large catchments, this model does not require data on the characteristic soil type or the percentage of outflow areas (wet lands) in the catchment, as in most previous models, since in practice it is very difficult to obtain reliable data on characteristic soil type or percentage of outflow areas, especially in large and topographically complex catchments. Modelled values have been compared to empirical data from rivers sites covering a wide domain (catchment areas from 3000 to 3,000,000 km2, precipitation from 400 to 1700 mm/year; fallouts from 1600 to 280,000 Bq/m2; altitudes from 0 to 1000 m.a.s.l. and latitudes from 41 degrees to 72 degrees N). The river model with its sub-model for fixation predicts close to the uncertainty factors given by the empirical data, which have been shown to be about a factor of 1.6 for

  7. Evaluation of the Fallout Protection Afforded by Brookhaven National Laboratory Medical Research Center

    DTIC Science & Technology

    1961-10-01

    EFFECTS TEST OPERATIONS U.S. ATOMIC ENERGY COMMISSION NOTICE This report is published in the interest of providing information which may prove of...value to the reader in his study of effects data derived principally from nuclear weapons tests and from experiments designed to duplicate various...Z. Burson, and J. Jacovitch Approved by: R. L. CORSBIE Director Civil Effects Test Operations Edgerton, Germeshausen & Grier, Inc. Santa Barbara

  8. Poisson's ratio of individual metal nanowires.

    PubMed

    McCarthy, Eoin K; Bellew, Allen T; Sader, John E; Boland, John J

    2014-07-07

    The measurement of Poisson's ratio of nanomaterials is extremely challenging. Here we report a lateral atomic force microscope experimental method to electromechanically measure the Poisson's ratio and gauge factor of individual nanowires. Under elastic loading conditions we monitor the four-point resistance of individual metallic nanowires as a function of strain and different levels of electrical stress. We determine the gauge factor of individual wires and directly measure the Poisson's ratio using a model that is independently validated for macroscopic wires. For macroscopic wires and nickel nanowires we find Poisson's ratios that closely correspond to bulk values, whereas for silver nanowires significant deviations from the bulk silver value are observed. Moreover, repeated measurements on individual silver nanowires at different levels of mechanical and electrical stress yield a small spread in Poisson ratio, with a range of mean values for different wires, all of which are distinct from the bulk value.

  9. Bomb fall-out 236U as a global oceanic tracer using an annually resolved coral core

    PubMed Central

    Winkler, Stephan R.; Steier, Peter; Carilli, Jessica

    2012-01-01

    Anthropogenic 236U (t½=23.4 My) is an emerging isotopic ocean tracer with interesting oceanographic properties, but only with recent advances in accelerator mass spectrometry techniques is it now possible to detect the levels from global fall-out of nuclear weapons testing across the water column. To make full use of this tracer, an assessment of its input into the ocean over the past decades is required. We captured the bomb-pulse of 236U in an annually resolved coral core record from the Caribbean Sea. We thereby establish a concept which gives 236U great advantage – the presence of reliable, well-resolved chronological archives. This allows studies of not only the present distribution pattern, but gives access to the temporal evolution of 236U in ocean waters over the past decades. PMID:23564966

  10. [The role of vegetation cover in regulation of fluxes of the technogenic radionuclides at the different stages after radioactive fallout].

    PubMed

    Tsvetnova, O B; Shcheglov, A I

    2009-01-01

    In remote period after the radioactive fallout the biological cycle of 137Cs in pine forests of northern forest-steppe zone and Bryanskoe Polissye become different. In pine forests (northern forest-steppe zone) with dark grey forest soil 137Cs flux to the soil with litterfall exceeds its influx to the vegetation by a factor of 5. Thus biological cycle of 137Cs differs from the cycle of stable K and till now its main characteristic feature is domination of 137Cs flux to the soil with litterfall. In pine forests (Bryanskoe Polissye zone) with podzolic illuvialiron sandy soil annual 137Cs influx to above-ground vegetation via root uptake exceeds its return to the soil with litterfall. Under these conditions biological cycle of 137Cs approaches it to the biological cycle of stable K.

  11. Bomb fall-out 236U as a global oceanic tracer using an annually resolved coral core

    NASA Astrophysics Data System (ADS)

    Winkler, Stephan R.; Steier, Peter; Carilli, Jessica

    2012-12-01

    Anthropogenic 236U (t½=23.4 My) is an emerging isotopic ocean tracer with interesting oceanographic properties, but only with recent advances in accelerator mass spectrometry techniques is it now possible to detect the levels from global fall-out of nuclear weapons testing across the water column. To make full use of this tracer, an assessment of its input into the ocean over the past decades is required. We captured the bomb-pulse of 236U in an annually resolved coral core record from the Caribbean Sea. We thereby establish a concept which gives 236U great advantage - the presence of reliable, well-resolved chronological archives. This allows studies of not only the present distribution pattern, but gives access to the temporal evolution of 236U in ocean waters over the past decades.

  12. Bomb fall-out (236)U as a global oceanic tracer using an annually resolved coral core.

    PubMed

    Winkler, Stephan R; Steier, Peter; Carilli, Jessica

    2012-12-15

    Anthropogenic (236)U (t½=23.4 My) is an emerging isotopic ocean tracer with interesting oceanographic properties, but only with recent advances in accelerator mass spectrometry techniques is it now possible to detect the levels from global fall-out of nuclear weapons testing across the water column. To make full use of this tracer, an assessment of its input into the ocean over the past decades is required. We captured the bomb-pulse of (236)U in an annually resolved coral core record from the Caribbean Sea. We thereby establish a concept which gives (236)U great advantage - the presence of reliable, well-resolved chronological archives. This allows studies of not only the present distribution pattern, but gives access to the temporal evolution of (236)U in ocean waters over the past decades.

  13. The atomic orbitals of the topological atom.

    PubMed

    Ramos-Cordoba, Eloy; Salvador, Pedro; Mayer, István

    2013-06-07

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These correspond to atomic hybrids that closely resemble the core and valence shells of the atom. The occupation numbers of the remaining effective orbitals are almost negligible, except for atoms with hypervalent character. In addition, the molecular orbitals of a calculation can be exactly expressed as a linear combination of this orthonormalized set of numerical atomic orbitals, and the Mulliken population analysis carried out on this basis set exactly reproduces the original QTAIM atomic populations of the atoms. Approximate expansion of the molecular orbitals over a much reduced set of orthogonal atomic basis functions can also be accomplished to a very good accuracy with a singular value decomposition procedure.

  14. "Bohr's Atomic Model."

    ERIC Educational Resources Information Center

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  15. Modelling (137)Cs concentrations in moose (1986-2012) from areas highly contaminated by the Chernobyl fallout.

    PubMed

    Weimer, Robert N; Sundell-Bergman, Synnöve; Sonesten, Lars; Wikenros, Camilla; Rosén, Klas

    2016-08-01

    Data from long term annual monitoring of (137)Cs concentrations in harvested moose (Alces alces) were empirically modelled by applying multivariate data analysis that is able to from relatively raw datasets show how the many various impact variables are related (Principal component analysis, PCA). In the later stage regression modelling (Partial least squares, PLS) was applied to analyse which environmental and physiological factors were significant (i.e. of predictive value) based on the measured (X) activity concentrations in moose meat. The data sets originate from two different forest dominated areas in Sweden. One area is located inland (Heby municipality) and the other borders to the Baltic Sea (Gävle municipality). In inland with 20% farmland, GIS-software was used to calculate the proportion of different habitat types and (137)Cs deposition around individual killing spots. This model reveals that the proportions of farmland and forest around the killing spot were significant parameters, second to deposition and years since fallout. Significance was also obtained for the proportions of mire and water bodies, the amount of rain in summer and the age of the moose. In the other model based on data from the coastal area with only about 4% farmland, the coordinates of the moose killing spots were not recorded in the data sets. In the resulting model the temperature in July was the most important parameter, second to years since fallout. Significance was also found for the following parameters: temperature and rainfall in several summer months, the approximate north- and eastward location of the killing spot and to which age category (adult/calf) the harvested moose belonged.

  16. Migration of global radioactive fallout to the Arctic Ocean (on the example of the Ob's river drainage basin).

    PubMed

    Miroshnikov, A; Semenkov, I

    2012-11-01

    This article provides an assessment of the impact of global fallout on (137)Cs contamination in the bottom sediments of Kara Sea. The erosiveness of 10th-level river basins was estimated by landscape-geochemical and geomorphological characteristics. All 10th-level basins (n=154) were separated into three groups: mountain, mountain-lowland and plain. Four different types of basins were identified depending on the geochemical conditions of the migration of radiocaesium in the plain and mountain-lowland. Classifications of types were carried out using the geographic information systems-based approach. The Ob River's macroarena covers 3.5 million km(2). Internal drainage basins cover 23 % of the macroarena and accumulate whole radiocaesium from the global fallout. The remaining territory is transitional for the (137)Cs. The field research works performed in the three plain first-level basins allow one to estimate the radiocaesium run-off. The calculations show that 7 % of (137)Cs was removed from the first-level basin in arable land. Accumulation of radiocaesium in the first-level basin under undisturbed forest is 99.8 %. The research shows that (137)Cs transfer from the humid basins is in the range of 6.9-25.5 TBq and for semi-humid basins 5.6-285.5 TBq. The areas of these basins cover 40 and 8 % of the Ob River's macroarena, respectively. Drainage lakes and reservoir drainage basins make up 22 % of the macroarena. Mountainous and semi-arid drainage basins cover 7 % of the macroarena.

  17. Trends in childhood leukaemia in the Nordic countries in relation to fallout from atmospheric nuclear weapons testing.

    PubMed Central

    Darby, S. C.; Olsen, J. H.; Doll, R.; Thakrar, B.; Brown, P. D.; Storm, H. H.; Barlow, L.; Langmark, F.; Teppo, L.; Tulinius, H.

    1992-01-01

    OBJECTIVE--To obtain further information about the risks of childhood leukaemia after exposure to ionising radiation at low doses and low dose rates before or after birth or to the father's testes shortly before conception. DESIGN--Observational study of trends in incidence of childhood leukaemia in relation to estimated radiation exposures due to fallout from atmospheric nuclear weapons testing during the 1950s and 1960s. SETTING--Nordic countries. SUBJECTS--Children aged under 15 years. MAIN OUTCOME MEASURES--Incidence rates of leukaemia by age at diagnosis, sex, country, and calendar year of diagnosis or year of birth; exposure category; relation between leukaemia and exposure for children aged 0-14 and 0-4 separately. RESULTS--During the high fallout period the average estimated dose equivalent to the fetal red bone marrow was around 140 mu Sv and the average annual testicular dose 140 mu Sv. There was little evidence of increased incidence of leukaemia among children born in these years. Doses to the red bone marrow of a child after birth were higher, and during the high exposure period children would have been subjected to an additional dose equivalent of around 1500 mu Sv, similar to doses received by children in several parts of central and eastern Europe owing to the Chernobyl accident and about 50% greater than the annual dose equivalent to the red bone marrow of a child from natural radiation. leukaemia incidence and red marrow dose was not related overall, but rates of leukaemia in the high exposure period were slightly higher than in the surrounding medium exposure period (relative risk for ages 0-14: 1.07, 95% confidence interval 1.00 to 1.14; for ages 0-4: 1.11, 1.00 to 1.24). CONCLUSIONS--Current predicted risks of childhood leukaemia after exposure to radiation are not greatly underestimated for low dose rate exposures. PMID:1586779

  18. Short term soil erosion dynamics in alpine grasslands - Results from a Fallout Radionuclide repeated-sampling approach

    NASA Astrophysics Data System (ADS)

    Arata, Laura; Meusburger, Katrin; Zehringer, Markus; Ketterer, Michael E.; Mabit, Lionel; Alewell, Christine

    2016-04-01

    Improper land management and climate change has resulted in accelerated soil erosion rates in Alpine grasslands. To efficiently mitigate and control soil erosion and reduce its environmental impact in Alpine grasslands, reliable and validated methods for comprehensive data generation on its magnitude and spatial extent are mandatory. The use of conventional techniques (e.g. sediment traps, erosion pins or rainfall simulations) may be hindered by the extreme topographic and climatic conditions of the Alps. However, the application of the Fallout Radionuclides (FRNs) as soil tracers has already showed promising results in these specific agro-ecosystems. Once deposited on the ground, FRNs strongly bind to fine particles at the surface soil and move across the landscape primarily through physical processes. As such, they provide an effective track of soil and sediment redistribution. So far, applications of FRN in the Alps include 137Cs (half-life: 30.2 years) and 239+240Pu (239Pu [half-life = 24110 years] and 240Pu [half-life = 6561 years]). To investigate short term (4-5 years) erosion dynamics in the Swiss Alps, the authors applied a FRNs repeated sampling approach. Two study areas in the central Swiss Alps have been investigated: the Urseren Valley (Canton Uri), where significant land use changes occurred in the last centuries, and the Piora Valley (Canton Ticino), where land use change plays a minor role. Soil samples have been collected at potentially erosive sites along the valleys over a period of 4-5 years and measured for 137Cs and 239+240Pu activity. The inventory change between the sampling years indicates high erosion and deposition dynamics at both valleys. High spatial variability of 137Cs activities at all sites has been observed, reflecting the heterogeneous distribution of 137Cs fallout after the Chernobyl power plant accident in 1986. Finally, a new modelling technique to convert the inventory changes to quantitative estimates of soil erosion has

  19. Cesium, iodine and tritium in NW Pacific waters - a comparison of the Fukushima impact with global fallout

    NASA Astrophysics Data System (ADS)

    Povinec, P. P.; Aoyama, M.; Biddulph, D.; Breier, R.; Buesseler, K.; Chang, C. C.; Golser, R.; Hou, X. L.; Ješkovský, M.; Jull, A. J. T.; Kaizer, J.; Nakano, M.; Nies, H.; Palcsu, L.; Papp, L.; Pham, M. K.; Steier, P.; Zhang, L. Y.

    2013-04-01

    Radionuclide impact of the Fukushima Dai-ichi nuclear power plant accident on the distribution of radionuclides in seawater of the NW Pacific Ocean is compared with global fallout from atmospheric tests of nuclear weapons. Surface and water column seawater samples collected during the international expedition in June 2011 were analyzed for 134Cs, 137Cs, 129I and 3H. The 137Cs, 129I and 3H levels in surface seawater offshore Fukushima varied between 0.002-3.5 Bq L-1, 0.01-0.8 μ Bq L-1, and 0.05-0.15 Bq L-1, respectively. At the sampling site about 40 km from the coast, where all three radionuclides were analyzed, the Fukushima impact on the levels of these three radionuclides represent an increase above the global fallout background by factors of about 1000, 30 and 3, respectively. The water column data indicate that the transport of Fukushima-derived radionuclides downward to the depth of 300 m has already occurred. The observed 137Cs levels in surface waters and in the water column are in reasonable agreement with predictions obtained from the Ocean General Circulation Model, which indicates that the radionuclides have been transported from the Fukushima coast eastward. The 137Cs inventory in the water column (the area from 34 to 37° N, and from 142 to 147° E) due to the Fukushima accident is estimated to be about 2.2 PBq. The amount of 129I and 3H released and deposited on the NW Pacific Ocean after the Fukushima accident was estimated to be about 7 GBq and 0.1 PBq, respectively. Due to a suitable residence time in the ocean, Fukushima-derived radionuclides will provide useful tracers for isotope oceanography studies on the transport of water masses in the NW Pacific Ocean.

  20. Atomic Energy Basics, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

    This booklet is part of the "Understanding the Atom Series," though it is a later edition and not included in the original set of 51 booklets. A basic survey of the principles of nuclear energy and most important applications are provided. These major topics are examined: matter has molecules and atoms, the atom has electrons, the nucleus,…

  1. Atomic displacements in quantum crystals

    NASA Astrophysics Data System (ADS)

    Dusseault, Marisa; Boninsegni, Massimo

    2017-03-01

    Displacements of atoms and molecules away from lattice sites in helium and parahydrogen solids at low temperature have been studied by means of quantum Monte Carlo simulations. In the bcc phases of 3He and 4He, atomic displacements are largely quantum-mechanical in character, even at melting. The computed Lindemann ratio at melting is found to be in good agreement with experimental results for 4He. Unlike the case of helium, in solid parahydrogen there exists near melting a significant thermal contribution to molecular vibrations, accounting for roughly half of the total effect. Although the Lindemann ratio at melting is in quantitative agreement with experiment, computed molecular mean square fluctuations feature a clear temperature dependence, in disagreement with recent experimental observations.

  2. Offer/Acceptance Ratio.

    ERIC Educational Resources Information Center

    Collins, Mimi

    1997-01-01

    Explores how human resource professionals, with above average offer/acceptance ratios, streamline their recruitment efforts. Profiles company strategies with internships, internal promotion, cooperative education programs, and how to get candidates to accept offers. Also discusses how to use the offer/acceptance ratio as a measure of program…

  3. Distribution pattern of artificial radionuclides in the Baltic Sea in the special event of the Chernobyl fallout.

    PubMed

    Weiss, Dietmar

    2011-09-01

    Extensive investigations on radioactive contamination and on its spatial and temporal changes in the Baltic Sea have been carried out by the National Board for Atomic Safety and Radiation Protection since 1986. The results were compared with data obtained in the years prior to the Chernobyl accident. Due to the composition of the accidental releases and the physical half-life of the released radionuclides, special emphasis was laid on Cs-134 and Cs-137. Other radionuclides, such as H-3, Sr-90, Ru-103 and Ru-106 turned out to be insignificant compared with the caesium isotopes. The radionuclides Cs-134 and Cs-137 accounting for the highest percentage of the released long-lived radionuclides were deposited on the sea surface with an initial ratio of 0.5. Their distribution pattern on the sea surface was affected by the meteorological conditions prevailing during the release period. The horizontal dislocation of higher contaminated water masses and the vertical penetration of radioactive caesium resulted in a prolonged uniformity of the contamination level of the Baltic Sea.

  4. Negative Poisson's ratio in rippled graphene.

    PubMed

    Qin, Huasong; Sun, Yu; Liu, Jefferson Zhe; Li, Mengjie; Liu, Yilun

    2017-03-10

    In this work, we perform molecular dynamics (MD) simulations to study the effect of rippling on the Poisson's ratio of graphene. Due to the atomic scale thickness of graphene, out-of-plane ripples are generated in free standing graphene with topological defects (e.g. heptagons and pentagons) to release the in-plane deformation energy. Through MD simulations, we have found that the Poisson's ratio of rippled graphene decreases upon increasing its aspect ratio η (amplitude over wavelength). For the rippled graphene sheet η = 0.188, a negative Poisson's ratio of -0.38 is observed for a tensile strain up to 8%, while the Poisson's ratio for η = 0.066 is almost zero. During uniaxial tension, the ripples gradually become flat, thus the Poisson's ratio of rippled graphene is determined by the competing factors of the intrinsic positive Poisson's ratio of graphene and the negative Poisson's ratio due to the de-wrinkling effect. Besides, the rippled graphene exhibits excellent fracture strength and toughness. With the combination of its auxetic and excellent mechanical properties, rippled graphene may possess potential for application in nano-devices and nanomaterials.

  5. Radiation and the sex ratio in man.

    PubMed

    SCHULL, W J; NEEL, J V

    1958-08-15

    An analysis of new data concerning the sex of children born to the survivors of the atomic bombings of Hiroshima and Nagasaki, together with a reanalysis of the data previously presented by Neel and Schull (9), reveals significant changes in the sex ratio of these children, changes in the direction to be expected if exposure had resulted in the induction of sex-linked lethal mutations (16).

  6. Effects of grain size, mineralogy, and acid-extractable grain coatings on the distribution of the fallout radionuclides 7Be, 10Be, 137Cs, and 210Pb in river sediment

    NASA Astrophysics Data System (ADS)

    Singleton, Adrian A.; Schmidt, Amanda H.; Bierman, Paul R.; Rood, Dylan H.; Neilson, Thomas B.; Greene, Emily Sophie; Bower, Jennifer A.; Perdrial, Nicolas

    2017-01-01

    Grain-size dependencies in fallout radionuclide activity have been attributed to either increase in specific surface area in finer grain sizes or differing mineralogical abundances in different grain sizes. Here, we consider a third possibility, that the concentration and composition of grain coatings, where fallout radionuclides reside, controls their activity in fluvial sediment. We evaluated these three possible explanations in two experiments: (1) we examined the effect of sediment grain size, mineralogy, and composition of the acid-extractable materials on the distribution of 7Be, 10Be, 137Cs, and unsupported 210Pb in detrital sediment samples collected from rivers in China and the United States, and (2) we periodically monitored 7Be, 137Cs, and 210Pb retention in samples of known composition exposed to natural fallout in Ohio, USA for 294 days. Acid-extractable materials (made up predominately of Fe, Mn, Al, and Ca from secondary minerals and grain coatings produced during pedogenesis) are positively related to the abundance of fallout radionuclides in our sediment samples. Grain-size dependency of fallout radionuclide concentrations was significant in detrital sediment samples, but not in samples exposed to fallout under controlled conditions. Mineralogy had a large effect on 7Be and 210Pb retention in samples exposed to fallout, suggesting that sieving sediments to a single grain size or using specific surface area-based correction terms may not completely control for preferential distribution of these nuclides. We conclude that time-dependent geochemical, pedogenic, and sedimentary processes together result in the observed differences in nuclide distribution between different grain sizes and substrate compositions. These findings likely explain variability of measured nuclide activities in river networks that exceeds the variability introduced by analytical techniques as well as spatial and temporal differences in erosion rates and processes. In short, we

  7. High Aspect Ratio Wrinkles

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Cheng; Crosby, Alfred

    2015-03-01

    Buckling-induced surface undulations are widely found in living creatures, for instance, gut villi and the surface of flower petal cells. These undulations provide unique functionalities with their extremely high aspect ratios. For the synthetic systems, sinusoidal wrinkles that are induced by buckling a thin film attached on a soft substrate have been proposed to many applications. However, the impact of the synthetic wrinkles have been restricted by limited aspect ratios, ranging from 0 to 0.35. Within this range, wrinkle aspect ratio is known to increase with increasing compressive strain until a critical strain is reached, at which point wrinkles transition to localizations, such as folds or period doublings. Inspired by the living creatures, we propose that wrinkles can be stabilized in high aspect ratio by manipulating the strain energy in the substrate. We experimentally demonstrate this idea by forming a secondary crosslinking network in the wrinkled surface and successfully achieve aspect ratio as large as 0.8. This work not only provides insights for the mechanism of high aspect ratio structures seen in living creatures, but also demonstrates significant promise for future wrinkle-based applications.

  8. Collaborative Cyber-infrastructures for the Management of the UNESCO-IGCP Research Project "Forecast of tephra fallout"

    NASA Astrophysics Data System (ADS)

    Folch, A.; Costa, A.; Cordoba, G.

    2009-04-01

    Tephra fallout following explosive volcanic eruptions produces several hazardous effects on inhabitants, infrastructure, and property and represents a serious threat for communities located around active volcanoes. In order to mitigate the effects on the surrounding areas, scientists and civil decision-making authorities need reliable short-term forecasts during episodes of eruptive crisis and long-term probabilistic maps to plan territorial policies and land use. Modelling, together with field studies and volcano monitoring, constitutes an indispensable tool to achieve these objectives. The UNESCO-IGCP research project proposal "Forecast of tephra fallout" has the aim to produce a series of tools capable to elaborate both short-term forecasts and long-term hazard assessments using the cutting-edge models for tephra transport and sedimentation. A special project website will be designed to supply a set of models, procedures and expertise to several Latino-American Institutes based in countries seriously threatened by this geo-hazard (Argentina, Chile, Colombia, Ecuador, Mexico, and Nicaragua). This will proportionate to the final users a tool to elaborate short-term forecasts of tephra deposition on the ground, and determine airborne ash concentrations (a quantity of special relevance for aerial navigation safety) during eruptions and emergencies. The project web-site will have a public section and a password-protected area to exchange information and data among participants and, eventually, to allow remote execution of high-resolution mesoscale meteorological forecasts at the BSC facilities. The public website section will be updated periodically and will include sections describing the project objectives and achievements as well as the hazard maps for the investigated volcanoes, and will be linked to other relevant websites such as IAVCEI, IGCP, IUGS and UNESCO homepages. A part of the public section of the website will be devoted to disseminate achieved

  9. Cesium, iodine and tritium in NW Pacific waters - a comparison of the Fukushima impact with global fallout

    NASA Astrophysics Data System (ADS)

    Povinec, P. P.; Aoyama, M.; Biddulph, D.; Breier, R.; Buesseler, K.; Chang, C. C.; Golser, R.; Hou, X. L.; Ješkovský, M.; Jull, A. J. T.; Kaizer, J.; Nakano, M.; Nies, H.; Palcsu, L.; Papp, L.; Pham, M. K.; Steier, P.; Zhang, L. Y.

    2013-08-01

    Radionuclide impact of the Fukushima Dai-ichi nuclear power plant accident on the distribution of radionuclides in seawater of the NW Pacific Ocean is compared with global fallout from atmospheric tests of nuclear weapons. Surface and water column samples collected during the Ka'imikai-o-Kanaloa (KOK) international expedition carried out in June 2011 were analyzed for 134Cs, 137Cs, 129I and 3H. The 137Cs, 129I and 3H levels in surface seawater offshore Fukushima varied between 0.002-3.5 Bq L-1, 0.01-0.8 μBq L-1, and 0.05-0.15 Bq L-1, respectively. At the sampling site about 40 km from the coast, where all three radionuclides were analyzed, the Fukushima impact on the levels of these three radionuclides represents an increase above the global fallout background by factors of about 1000, 50 and 3, respectively. The water column data indicate that the transport of Fukushima-derived radionuclides downward to the depth of 300 m has already occurred. The observed 137Cs levels in surface waters and in the water column are compared with predictions obtained from the ocean general circulation model, which indicates that the Kuroshio Current acts as a southern boundary for the transport of the radionuclides, which have been transported from the Fukushima coast eastward in the NW Pacific Ocean. The 137Cs inventory in the water column is estimated to be about 2.2 PBq, what can be regarded as a lower limit of the direct liquid discharges into the sea as the seawater sampling was carried out only in the area from 34 to 37° N, and from 142 to 147° E. About 4.6 GBq of 129I was deposited in the NW Pacific Ocean, and 2.4-7 GBq of 129I was directly discharged as liquid wastes into the sea offshore Fukushima. The total amount of 3H released and deposited over the NW Pacific Ocean was estimated to be 0.1-0.5 PBq. These estimations depend, however, on the evaluation of the total 137Cs activities released as liquid wastes directly into the sea, which should improve when more data are

  10. The Use of High Resolution NWP data for Dispersion Modeling of Airborne Volcanic Ash and Tephra Fallout

    NASA Astrophysics Data System (ADS)

    Morton, D.; Webley, P. W.; Dean, K.; Peterson, R.

    2006-12-01

    Ash dispersion models are routinely used to predict the movement of ash clouds from volcanic eruptions. The Puff dispersion model is used by the Alaska Volcano Observatory (AVO) in the North Pacific region as both an operational tool and for retrospective analysis of past events. The model requires some basic information to initialize a prediction including location of volcano, estimated plume height, particle size, initial distribution and the wind field to be used. Puff tracks the movement of a set number of hypothetical particles thereby predicting the transport of volcanic ash, and the location and relative amount of ash fallout. In the recent past, global, mesoscale and regional meteorological forecast models have been used as initialization for the Puff wind fields. These include the North American Mesoscale Model (NAM) and the Global Forecast System (GFS) model, at horizontal resolutions ranging from a few 10's to many 10's km. To use Puff as a tool for predicting ash/tephra fallout requires a much higher spatial resolution to resolve the low level wind patterns. Recently, high spatial resolution meteorological forecasts have been made possible using the Weather Research and Forecasting (WRF) model and incorporating its forecasts as initialization data for Puff. WRF can provide forecasts from sub km to 10's of km resolution and using nested grids can provide data at a several resolutions. WRF can be initialized using large scale operational models or re-analysis data for past events. Here we will show where WRF has been used as the initialization model for Puff at four eruptions within the NOPAC region (Mt. St Helens [1980], Mt. Spurr [1992], Mt. Redoubt [1989/90] and Mt. Augustine [2006]). In addition, the IAVCEI working group on modeling tephra fall hazards has outlined five eruptions (including Mt. St Helens) to study and we include those here as well, (El Chichon [1982], Cerro Negro [1995], Soufriere Hills [1997] and Mt. Etna [1998]). For this study, the

  11. Combined use of fallout radionuclides and stable isotopes for investigating soil erosion processes in a Moroccan watershed

    NASA Astrophysics Data System (ADS)

    Benmansour, Moncef; Mabit, Lionel; Zouagui, Anis; Amenzou, Nouredinne; Sabir, Mohamed; Nouira, Asmae; Brandt, Christian; Rasche, Frank; Naimi, Mustapha; Chikhaoui, Mohamed; Marah, Hamid; Benkdad, Azzouz; Taous, Fouad

    2015-04-01

    On-site and off-site impacts associated with land degradation by soil erosion are a major concern in Morocco. This study aimed to use fallout radionuclides (FRNs): Caesium-137 (137Cs), excess Lead-210 (210Pbex) and Beryllium-7 (7Be) in combination with carbon and nitrogen stable isotopes (i.e. Carbon-13 (13C) and Nitrogen-15 (15N)) in estimating soil loss in the "My Bouchta" watershed and the origin of sediment deposits in a downstream water reservoir (i.e. "Talembout"). Using 137Cs, the net soil erosion rate, for the "My Bouchta" watershed over a period of 50 years, was estimated at 23 t/ha/yr with a main sediment contribution (> 90{%}) from the agricultural fields, the forest and shrub fields contributing to less than 10{%} of the overall sediment production. This result indicates clearly the role and the effectiveness of the forest plantations and vegetation cover to protect soil resource against erosion processes. The use of the 210Pb^ex technique in three different fields further highlighted that soil erosion rates over a period of 100 years were lower than those obtained by 137Cs reflecting the increase of soil loss during the last decades. Tests of fallout 7Be associated with short rainfall events in four fields confirmed the results obtained with 137Cs, that areas under natural vegetation were protected against erosion. Sedimentation rates were assessed for the "Talembout" water reservoir and the mean values obtained for two sediment cores using 210Pbex and the Constant Rate of Supply (CRS) model were about 0.51-0.58 g/cm^2/yr. The obtained results showed also a significant yearly increase of the sedimentation rate. The results derived from the stable isotopes depth profiles indicated similar behavior for forest and shrub fields. Furthermore, strong correlation between δ13C and total C was observed for this type of land use while for the agricultural fields, the correlation was not significant. In addition, the sediment profile of N-15 indicated an

  12. Neutral atom traps.

    SciTech Connect

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  13. Chernobyl fallout in the uppermost (0-3 cm) humus layer of forest soil in Finland, North East Russia and the Baltic countries in 2000--2003.

    PubMed

    Ylipieti, J; Rissanen, K; Kostiainen, E; Salminen, R; Tomilina, O; Täht, K; Gilucis, A; Gregorauskiene, V

    2008-12-15

    The situation resulting from the Chernobyl fallout in 1987 was compared to that in 2000--2001 in Finland and NW Russia and that in 2003 in the Baltic countries. 786 humus (0-3 cm layer) samples were collected during 2000--2001 in the Barents Ecogeochemistry Project, and 177 samples in the Baltic countries in 2003. Nuclides emitting gamma-radiation in the 0-3 cm humus layer were measured by the Radiation and Nuclear Safety Authority-STUK in Finland. In 1987 the project area was classified by the European Commission into four different fallout classes. 137Cs inventory Bg/m2 levels measured in 2000--2003 were compared to the EU's class ranges. Fitting over the whole project area was implemented by generalizing the results for samples from the Baltic countries, for which Bq/m2 inventories could be calculated. A rough estimation was made by comparing the mass of organic matter and humus with 137Cs concentrations in these two areas. Changes in 137Cs concentration levels are illustrated in both thematic maps and tables. Radionuclide 137Cs concentrations (Bq/kg d.w.) were detected in the humus layer at all the 988 sampling sites. 134Cs was still present in 198 sites 15 years after the nuclear accident in Chernobyl. No other anthropogenic nuclides emitting gamma-radiation were detected, but low levels of 60Co, 125Sb and 154Eu isotopes were found in 14 sites. Fifteen years after the Chernobyl accident, the radioactive nuclide 137Cs was and still is the most significant fallout radionuclide in the environment and in food chains. The results show that the fallout can still be detected in the uppermost humus layer in North East Europe.

  14. Comparative analysis of Pu body burdens, induced by releases from atomic enterprises and global fallouts. Cancer risk, connected with plutonium accumulation

    SciTech Connect

    Khokhryakov, V.F.; Suslova, C.G.; Skryabin, A.M.

    1993-12-31

    The paper presents: results of the analysis of dynamics of body burdens of Pu in adult inhabitants of Chelyabinsk-65 (not occupationally exposed) and of the Gomel region for 1990-1991. The data are based on radiochemical analysis of Pu in human organs and tissues. Comparison with the publicated data on global Pu and our date for five human autopsies revealed, that values of Pu body burdens in Chelyabinsk-65 residents were 30 times higher than global levels and depended on the period of residence in the town. The Pu body content in the Gomel region in 4-5 years after Chernobyl is, on average, 3-4 times as much as global levels. Activity of PU-238 in various organs is 4,7-26.0% (on the average 13.5{+-}5.0%) of alpha-activity of Pu-238+Pu-239,240. Expected number of cancer induced by incorporated plutonium is approximately the same for two population groups, despite of their difference in number and doesn`t differ of global level more than one order.

  15. Flame-in-gas-shield and miniature diffusion flame hydride atomizers for atomic fluorescence spectrometry: optimization and comparison

    NASA Astrophysics Data System (ADS)

    Marschner, Karel; Musil, Stanislav; Dědina, Jiří

    2015-07-01

    A detailed optimization of relevant experimental parameters of two hydride atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH4 in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the atomizers (sensitivity, noise, limits of detection) were compared. Under optimum conditions sensitivity obtained with flame-in-gas-shield atomizer was approximately twice higher than with miniature diffusion flame. The additional advantage of flame-in-gas-shield atomizer is significantly lower flame emission resulting in a better signal to noise ratio. The resulting arsenic limits of detection for miniature diffusion flame and flame-in-gas-shield atomizer were 3.8 ng l- 1 and 1.0 ng l- 1, respectively.

  16. Assessment of dry and wet atmospheric deposits of radioactive aerosols: application to Fukushima radiocaesium fallout.

    PubMed

    Gonze, Marc-André; Renaud, Philippe; Korsakissok, Irène; Kato, Hiroaki; Hinton, Thomas G; Mourlon, Christophe; Simon-Cornu, Marie

    2014-10-07

    The Fukushima Dai-ichi nuclear accident led to massive atmospheric deposition of radioactive substances onto the land surfaces. The spatial distribution of deposits has been estimated by Japanese authorities for gamma-emitting radionuclides through either airborne monitoring surveys (since April 2011) or in situ gamma-ray spectrometry of bare soil areas (since summer 2011). We demonstrate that significant differences exist between the two surveys for radiocaesium isotopes and that these differences can be related to dry deposits through the use of physically based relationships involving aerosol deposition velocities. The methodology, which has been applied to cesium-134 and cesium-137 deposits within 80-km of the nuclear site, provides reasonable spatial estimations of dry and wet deposits that are discussed and compared to atmospheric numerical simulations from the Japanese Atomic Energy Agency and the French Institute of Radioprotection and Nuclear Safety. As a complementary approach to numerical simulations, this field-based analysis has the possibility to contribute information that can be applied to the understanding and assessment of dose impacts to human populations and the environment around Fukushima.

  17. Magneto-optical trap for thulium atoms

    SciTech Connect

    Sukachev, D.; Sokolov, A.; Chebakov, K.; Akimov, A.; Kanorsky, S.; Kolachevsky, N.; Sorokin, V.

    2010-07-15

    Thulium atoms are trapped in a magneto-optical trap using a strong transition at 410 nm with a small branching ratio. We trap up to 7x10{sup 4} atoms at a temperature of 0.8(2) mK after deceleration in a 40-cm-long Zeeman slower. Optical leaks from the cooling cycle influence the lifetime of atoms in the magneto-optical trap which varies between 0.3 and 1.5 s in our experiments. The lower limit for the leaking rate from the upper cooling level is measured to be 22(6) s{sup -1}. The repumping laser transferring the atomic population out of the F=3 hyperfine ground-state sublevel gives a 30% increase for the lifetime and the number of atoms in the trap.

  18. Probabilistic evaluation of the physical impact of future tephra fallout events for the Island of Vulcano, Italy

    NASA Astrophysics Data System (ADS)

    Biass, Sebastien; Bonadonna, Costanza; di Traglia, Federico; Pistolesi, Marco; Rosi, Mauro; Lestuzzi, Pierino

    2016-05-01

    A first probabilistic scenario-based hazard assessment for tephra fallout is presented for La Fossa volcano (Vulcano Island, Italy) and subsequently used to assess the impact on the built environment. Eruption scenarios are based upon the stratigraphy produced by the last 1000 years of activity at Vulcano and include long-lasting Vulcanian and sub-Plinian eruptions. A new method is proposed to quantify the evolution through time of the hazard associated with pulsatory Vulcanian eruptions lasting from weeks to years, and the increase in hazard related to typical rainfall events around Sicily is also accounted for. The impact assessment on the roofs is performed by combining a field characterization of the buildings with the composite European vulnerability curves for typical roofing stocks. Results show that a sub-Plinian eruption of VEI 2 is not likely to affect buildings, whereas a sub-Plinian eruption of VEI 3 results in 90 % of the building stock having a ≥12 % probability of collapse. The hazard related to long-lasting Vulcanian eruptions evolves through time, and our analysis shows that the town of Il Piano, located downwind of the preferential wind patterns, is likely to reach critical tephra accumulations for roof collapse 5-9 months after the onset of the eruption. If no cleaning measures are taken, half of the building stock has a probability >20 % of suffering roof collapse.

  19. Biomonitoring fallout 137Cs in resident and migratory fishes collected along the southern coast of India and assessment of dose.

    PubMed

    Khan, Mohan Feroz; Wesley, Samuel Godwin

    2012-05-01

    The globally distributed fallout radionuclide (137)Cs was monitored in 25 resident and 22 migratory fish species collected from some regions of west and east coast of southern India to establish a baseline data. The samples were collected during June 2008 to June 2009. Higher level of (137)Cs was noted in planktivorous fishes and lower level in herbivores. A significant variation in (137)Cs was observed between fishes with different feeding habits and different migratory pattern. Oceanodromic migratory fishes displayed higher cesium levels than other migratory types. Similarly, migratory fishes displayed higher (137)Cs concentration compared to resident fishes. The overall range of (137)Cs varied from 0.06 to 0.3 Bq/kg in fishes. The biological concentration varied from 55 to 250. The average external dose rate to fishes was calculated to be 2.7 × 10(-7) μGy/h, while the internal dose rate varied from 8.50 × 10(-6) to 5.27 × 10(-5) μGy/h. The hazard quotient for fishes was found to be less than 1. The average intake of (137)Cs via fishes to the public was calculated to be 3.5 Bq/year and subsequently the committed effective dose was 0.05 μSv/year. The data obtained were less than global average and comparable to those of many regions.

  20. EPR DOSIMETRY STUDY FOR POPULATION RESIDING IN THE VICINITY OF FALLOUT TRACE FOR NUCLEAR TEST ON 7 AUGUST 1962.

    PubMed

    Zhumadilov, Kassym Sh; Ivannikov, Alexander I; Stepanenko, Valeriy F; Toyoda, Shin; Skvortsov, Valeriy G; Hoshi, Masaharu

    2016-12-01

    The method of electron paramagnetic resonance (EPR) dosimetry using extracted teeth has been applied to human tooth enamel to obtain individual absorbed doses of residents of settlements in the vicinity of the central axis of radioactive fallout trace from the contaminating surface nuclear test on 7 August 1962. Most of the settlements (Kurchatov, Akzhar, Begen, Buras, Grachi, Mayskoe, Semenovka) are located from 70 to 120 km to the North-East from the epicenter of the explosion at the Semipalatinsk Nuclear Test Site (SNTS). This region is basically an agricultural region. A total of 57 teeth samples were collected from these sites. Eight teeth from residents of the Kokpekty settlement, which was not subjected to any radioactive contamination and located 400 km to the Southeast from SNTS, were chosen as a control. The principal findings, using this method, were that the average excess dose obtained after subtraction of the natural background radiation was 13 mGy and ranged up to about 100 mGy all for residents in this region.

  1. Tephra fallout hazard assessment at Vesuvius: the effect of uncertainties on the wind and the eruption source parameters

    NASA Astrophysics Data System (ADS)

    Macedonio, Giovanni; Costa, Antonio; Scollo, Simona; Neri, Augusto

    2016-04-01

    In this study we investigate the effect of using different meteorological datasets and eruption source parameters on tephra fallout hazard assessment for a sub-Plinian eruption of Vesuvius, which is considered as a reference case for hazard assessment analysis of Vesuvius. We analyze the effect of using different meteorological data, from: i) radio-sounding carried out at the meteorological station of Brindisi (Italy) between 1962 and 1976 and between 1996 and 2012 and at Pratica di Mare (Rome, Italy) between 1995 and 2013; ii) meteorological models of the National Oceanic and Atmospheric Administration (NOAA) and of the European Centre for Medium-Range Weather Forecasts (ECMWF). Furthermore, we consider the effects of perturbing reference eruptive source parameters. In particular, we vary the total mass, the total grain-size distribution, the column height, and the effective atmospheric diffusion coefficient to evaluate how these parameters affect the hazard probability maps. Moreover, the effect of the seasonal variation of the wind field and the effect of the rain on the deposit loading are considered. Results show that the parameter that mostly affects hazard maps is, as expected, the total erupted mass; furthermore, keeping constant the erupted mass, the most important control on hazard is due to the particle terminal settling velocity distribution which is a function of the total grain-size distribution, particle density and shape. Within the considered range variations, the hazard depends less on the use of different meteorological datasets, column height and effective diffusion coefficient.

  2. Model testing using Chernobyl data: III. Atmospheric resuspension of radionuclides in Ukrainian regions impacted by Chernobyl fallout

    SciTech Connect

    Garger, E.K.; Hoffman, F.O.; Miller, C.W.

    1996-01-01

    The {open_quotes}Resuspension{close_quotes} scenario is designed to test models for atmospheric resuspension of radionuclides from contaminated soils. Resuspension can be a secondary source of contamination after a release has stopped, as well as a source of contamination for people and areas not exposed to the original release. The test scenario describes three exposure situations: (1) locations within the highly contaminated 30-km zone at Chernobyl, where exposures to resuspended material are probably dominated by local processes; (2) an urban area (Kiev) outside the 30-km zone, where local processes include extensive vehicular traffic; and (3) a location 40 to 60 km west of the Chernobyl reactor, where upwind sources of contamination are important. Input data include characteristics of the {sup 137}Cs ground contamination around specific sites, climatological data for the sites, characteristics of the terrain and topography, and locations of the sampling sites. Predictions are requested for average air concentrations of {sup 137}Cs at specified locations due to resuspension of Chernobyl fallout and for specified resuspension factors and rates. Test data (field measurements) are available for all endpoints. 9 refs., 4 figs., 11 tabs.

  3. Review of medical findings in a Marshallese population twenty-six years after accidental exposure to radioactive fallout

    SciTech Connect

    Conard, R.A.; Paglia, D.E.; Larsen, P.R.

    1980-01-01

    In March 1954, radioactive debris from a thermonuclear weapon test at Bikini Atoll deviated from predicted trajectories and contaminated several atolls in the northern Marshall Islands. As a result, 239 native inhabitants of these islands along with 28 American servicemen and 23 Japanese fishermen received variably severe exposures to diverse ionizing radiations. Fallout material consisted largely of mixed fission products with small amounts of neutron-induced radionuclides and minimal amounts of fissionable elements, producing a complex spectrum of electromagnetic and particulate radiation. Individuals were exposed to deeply penetrating, whole-body gamma irradiation, to internal radiation emitters assimilated either by inhalation or by ingestion of contaminated water and food, and to direct radiation from material accumulating on body surfaces. That accident initiated a cascade of events, medical, social and political, which continue in varying forms to this day. Most of these have been discussed in the open medical literature and in periodic reports issued by the medical team headquartered at Brookhaven National Laboratory. This report attempts to summarize some of the principal findings of medical significnce that have been observed during the subsequent 26 years with particular emphasis on the last six years.

  4. Heavy metals and trace elements in atmospheric fall-out: their relationship with topsoil and wheat element composition.

    PubMed

    Bermudez, Gonzalo M A; Jasan, Raquel; Plá, Rita; Pignata, María L

    2012-04-30

    The objectives of this study were to determine the average concentrations and deposition rates of 28 elements in atmospheric bulk deposition and to elucidate associations among topsoil, bulk deposition and wheat element composition. The fluxes of arsenic (As), copper (Cu), lead (Pb) and zinc (Zn) deposition in Córdoba were higher than in other agro-ecosystems, which reflects both natural (geochemistry and topsoil removal) and anthropogenic sources. High lanthanide, uranium (U) and thorium (Th) concentrations revealed the impact of an open cast uranium mine. The highest enrichment factors (EF) were those of Cu, Pb, Zn and nickel (Ni), with calcium (Ca) being the most prominent in the surroundings of a cement plant. Industries and the transport of airborne urban pollutants were the main anthropogenic sources for Ca, Cu, Ni, Pb, Zn, cadmium (Cd), iron (Fe), manganese (Mn) and antimony (Sb). The concentrations of metals in wheat grain were predicted using the topsoil and atmospheric fall-out composition with R(2)=0.90, with the latter being the best explanatory variable. The present study highlights the potential health hazards of wheat consumption (Environmental Protection Agency) by the assessment of heavy metals in bulk atmospheric deposition.

  5. Historical events associated with fallout from Bravo Shot-Operation castle and 25 y of medical findings

    SciTech Connect

    Cronkite, E.P.; Conard, R.A.; Bond, V.P.

    1997-07-01

    The events prior to Bravo Shot-Operation Castle that led to a decision not to evacuate the Marshallese prior to testing the thermonuclear bombs are presented as are the actions taken after the fallout incident in evacuating the exposed Marshallese and the military personnel. The initial medical effects (findings during first 6 wk after exposure) are briefly described and are followed by description of long term effects, namely, induction of one case or fatal acute myeloid leukemia and a large number of thyroid tumors (benign and malignant) in addition to hypothyroidism in adults and children and two cases of cretinism. The hypothyroidism and cretinism responded well to administration of oral thyroxine. During the first 25 y, there was also much unrest and political agitation initiated by exposed and unexposed Marshallese who were very unhappy as a result of relocation and inability to return to their homelands and feeling that all illness and deaths were due to the mysterious radiation, which they understandably did not understand. The difficulties in part were ameliorated by financial aid from the U.S. Congress. In view of one of us (EPC), no one agency or person in the U.S. Government was willing to take the responsibility for care of the Marshallese and its financing. The exposed and non-exposed Marshallese had their lifestyle changed, some of their homelands made uninhabitable for several years and could aptly be called {open_quotes}nuclear nomads,{close_quotes} an expression coined by others. 14 refs., 3 tabs.

  6. Tracing the sources of fine sediment in a nickel mining catchment using fallout and geogenic radionuclides (Thio River, New Caledonia)

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Navratil, Oldrich; Lefèvre, Irène; Laceby, J. Patrick; Allenbach, Michel

    2016-04-01

    Soil erosion and subsequent sediment transfer in rivers are exacerbated in tropical regions exposed to heavy rainfall. In New Caledonia, an island located in the southwestern part of the Southern Pacific Ocean, a significant fraction of this sediment is likely originating from tributaries draining nickel mining sites that are known to increase the terrigenous inputs to the rivers and, potentially to UNESCO World Heritage listed coastal lagoons. However, downstream contributions from these tributaries remain to be quantified. A pilot sediment tracing study has therefore been conducted in the 400-km² Thio River catchment. Fallout and geogenic radionuclides have been measured in sediment deposits collected in potential sources, i.e. (i) tributaries draining mines, (ii) tributaries draining 'natural' areas affected by landslides, and (iii) the main stem of the Thio River. Thorium-228 and Caesium-137 provide the best discrimination between sediment originating from the two tributaries. A distribution modelling approach was used to quantify the relative sediment contributions from these tributaries to the Thio River main stem. Results demonstrate that tributaries draining mining sites supply the majority of sediment (67-84%) to the main river. In the future, the validity of these results obtained on sediment deposits collected in April and May 2015 should be verified over a longer time period by applying a similar approach to sediment cores collected in the Thio river deltaic plain. Once validated, this method will be applicable to other catchments draining mines in New Caledonia to design appropriate measures to limit sediment supply to the lagoon.

  7. Ratio imaging instrumentation.

    PubMed

    Dunn, Kenneth; Maxfield, Frederick R

    2003-01-01

    Using ratio imaging to obtain quantitative information from microscope images is a powerful tool that has been used successfully in numerous studies. Although ratio imaging reduces the effects of many parameters that can interfere with accurate measurements, it is not a panacea. In designing a ratio imaging experiment, all of the potential problems discussed in this chapter must be considered. Undoubtedly, other problems that were not discussed can also interfere with accurate and meaningful measurements. Many of the problems discussed here were observed in the authors' laboratories. In our experience there are no standard routines or methods that can foresee every problem before it has been encountered. Good experimental design can minimize problems, but the investigator must continue to be alert. Progress in instrumentation continues to overcome some of the difficulties encountered in ratio imaging. CCD cameras with 12- to 14-bit pixel depth are being used more frequently, and several confocal microscope manufacturers are now also using 12-bit digitization. The dramatic increase in the use of confocal microscopes over the past decade is now causing microscope manufacturers to more critically evaluate the effect of axial chromatic aberration in objectives, and recent designs to minimize this problem are being implemented. Other developments such as the use of AOTFs to attenuate laser lines extend the applicability of ratio imaging. Ratio imaging is clearly applicable to a wide range of cell biological problems beyond its widespread use for measuring ion concentrations. Imaginative but careful use of this technique should continue to provide novel insights into the properties of cells.

  8. Atomic Particle Detection, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Hellman, Hal

    This booklet is one of the booklets in the "Understanding the Atom Series" published by the U. S. Atomic Energy Commission for high school science teachers and their students. The instruments used to detect both particles and electromagnetic radiation that emerge from the nucleus are described. The counters reviewed include ionization chambers,…

  9. Atomic Fuel, Understanding the Atom Series. Revised.

    ERIC Educational Resources Information Center

    Hogerton, John F.

    This publication is part of the "Understanding the Atom" series. Complete sets of the series are available free to teachers, schools, and public librarians who can make them available for reference or use by groups. Among the topics discussed are: What Atomic Fuel Is; The Odyssey of Uranium; Production of Uranium; Fabrication of Reactor…

  10. Spatial variability of fallout-90Sr in soil and vegetation of an alpine pasture.

    PubMed

    Schimmack, W; Kracke, W; Sommer, M

    2003-01-01

    According to the soil-to-plant transfer concept generally used in dose assessment modeling, the plant uptake of a radionuclide should depend linearly on its concentration in the soil. In order to validate this concept for (90)Sr in a semi-natural ecosystem, plant and soil samples were taken at 100 plots of a 100 x 100 m(2) area within an alpine pasture near Berchtesgaden, Germany. At three plots, the vertical distribution of (90)Sr in the soil was determined in addition. A statistically significant correlation between the soil and plant concentration of (90)Sr was not detectable (Spearman correlation coefficient R=-0.116, p>0.05) within the range of the Sr-concentration covered (15-548 Bq kg(-1) dry soil and 17-253 Bq kg(-1) dry plant material). Thus, the prerequisite of the soil-to-plant transfer concept was not fulfilled for (90)Sr at this site. Organic carbon and total nitrogen were also determined in the soil samples. Both elements were highly correlated (R=0.912, p<0.001), their ratio being C/N=10.9+/-0.7. While C was positively correlated with the (90)Sr concentrations in the soil (R=0.342, p<0.001), negative correlations were observed for the plant concentrations (R=-0.286, p<0.01) and the concentration ratios (R=-0.444, p<0.001) of (90)Sr. These results are compared with those recently obtained for (137)Cs by Bunzl et al. (J Environ Radioactiv 48 (2000) 145).

  11. The 12-13 January 2011 lava fountain of Mt. Etna volcano: total mass and grain-size evaluation of the fallout deposit

    NASA Astrophysics Data System (ADS)

    Andronico, Daniele; Cristaldi, Antonio; Lo Castro, Maria Deborah; Scollo, Simona

    2013-04-01

    South-East Crater (SEC) of Mt Etna, Italy, is renowned for its sequences of paroxysms, otherwise called episodic eruptions, which produced more than 150 events since 1998. Each episode typically gives rise to eruption columns and fallout deposits over distances of up to several tens of km from the vent. The last sequence consisted of twenty-five lava fountains occurred between 12 January 2011 and 24 April 2012. The 2011-12 sequence began from a pit-vent located on the eastern flank of the cone; with time, the intense and recurrent paroxysmal activity was able to build a new cone above the SEC, renamed New South-East Crater. The first episode was preceded by the resumption of Strombolian activity on 11 January 2011; late in the afternoon of 12 January, the increasing of explosion intensity and frequency led to the formation of powerful magma jets and a dense eruption column which moved toward SSW. The paroxysmal activity lasted about 1 hour and half; afterward it almost abruptly stopped early on 13 January, thus causing also the end of the eruption plume. Based on prevalent winds blowing in the Etnean area, most of the fallout deposits from Etna disperse their tephra fallout eastward toward the Valle del Bove depression, difficulty accessible in the upper part, then reaching the Ionian Sea. These peculiar conditions usually prevent direct observation of the deposit within 5 km from and 15 km beyond the eruptive vent. The 12-13 January lava fountain fallout, conversely, was dispersed over the South of Etna, exceeding the southern coastline of Sicily and thus giving the chance to map, sample and describe for more than 100 km the tephra fallout, passing from a black scoria deposit to ash deposit (90 % of which formed by sideromelane particles). In particular, the proximal deposit (up to 5 km of distance from SEC) was composed of a continuous to almost continuous tephra blanket containing decimetric-sized scoriae to coarse lapilli, while the most distal sites were

  12. Digit ratio in birds.

    PubMed

    Lombardo, Michael P; Thorpe, Patrick A; Brown, Barbara M; Sian, Katie

    2008-12-01

    The Homeobox (Hox) genes direct the development of tetrapod digits. The expression of Hox genes may be influenced by endogenous sex steroids during development. Manning (Digit ratio. New Brunswick, NJ: Rutgers University Press, 2002) predicted that the ratio between the lengths of digits 2 (2D) and 4 (4D) should be sexually dimorphic because prenatal exposure to estrogens and androgens positively influence the lengths of 2D and 4D, respectively. We measured digits and other morphological traits of birds from three orders (Passeriformes, house sparrow, Passer domesticus; tree swallow, Tachycineta bicolor; Pscittaciformes, budgerigar, Melopsittacus undulates; Galliformes, chicken, Gallus domesticus) to test this prediction. None were sexually dimorphic for 2D:4D and there were no associations between 2D:4D and other sexually dimorphic traits. When we pooled data from all four species after we averaged right and left side digits from each individual and z-transformed the resulting digit ratios, we found that males had significantly larger 2D:4D than did females. Tetrapods appear to be sexually dimorphic for 2D:4D with 2D:4D larger in males as in some birds and reptiles and 2D:4D smaller in males as in some mammals. The differences between the reptile and mammal lineages in the directionality of 2D:4D may be related to the differences between them in chromosomal sex determination. We suggest that (a) natural selection for a perching foot in the first birds may have overridden the effects of hormones on the development of digit ratio in this group of vertebrates and (b) caution be used in making inferences about prenatal exposure to hormones and digit ratio in birds.

  13. Production Ratio for Para- and Ortho-Ps in Photodetachment of Ps^-

    NASA Astrophysics Data System (ADS)

    Igarashi, Akinori

    2017-01-01

    Para- and ortho-Ps atoms are formed in the photodetachment of positronium negative ion. Since the lifetime against the pair annihilation is much shorter for para-Ps( ns) than for ortho-Ps( ns), the production ratio of para- and ortho-Ps atoms is important for the photodetachment experiments. We have derived the ratio explicitly.

  14. Measurements of atomic beam velocities with phase choppers and precision measurements of alkali atomic polarizabilities

    NASA Astrophysics Data System (ADS)

    Hromada, Ivan, Jr.

    Atom interferometers, in which de Broglie waves are coherently split and recombined to make interference fringes, now serve as precision measurement tools for several quantities in physics. Examples include measurements of Newton's constant, the fine structure constant, van der Waals potentials, and atomic polarizabilities. To make next-generation measurements of static electric dipole atomic polarizabilities with an atom beam interferometer, I worked on new methods to precisely measure the velocity distribution for atom beams. I will explain how I developed and used phase choppers to measure lithium, sodium, potassium, and cesium atomic beam velocities with 0.07% accuracy. I also present new measurements of polarizability for these atoms. I classify systematic errors into two broad categories: (1) fractional errors that are similar for all different types of atoms in our experiments, and (2), errors that scale with de Broglie wavelength or inverse atomic momentum in our experiments. This distinction is important for estimating the uncertainty in our measurements of ratios of atomic polarizabilities, e.g., alpha Cs/alphaNa = 2.488(12).

  15. Presenting the Bohr Atom.

    ERIC Educational Resources Information Center

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  16. Atomic alchemy: Weak decays of muonic and pionic atoms into other atoms

    SciTech Connect

    Greub, C.; Wyler, D.; Brodsky, S.J.; Munger, C.T.

    1995-10-01

    The rates of weak transitions between electromagnetic bound states, for example, ({pi}{sup +}{ital e}{sup {minus}}){r_arrow}({mu}{sup +}{ital e}{sup {minus}}){nu}{sub {mu}}, and the exclusive weak decay of a muonic atom into an electronic atom, ({ital Z}{mu}{sup {minus}}){r_arrow}({ital Ze}{sup {minus}}){nu}{sub {mu}}{bar {nu}}{sub {ital e}}, are calculated. For {ital Z}=80, relativistic effects are shown to increase the latter rate by a factor of 50 compared to the results of a nonrelativistic calculation. It is argued that the conditions for producing the muonic decay in neon gas ({ital Z}=10), where the branching ratio for the decay per captured muon is 1.7{times}10{sup {minus}9}, can be realized using cyclotron traps, though the prospect for a practical experiment seems remote. In lead the same ratio would be approximately {similar_to}1{times}10{sup {minus}6}. In addition to providing detailed information on the high momentum tail of the wave functions in atomic physics, these decays of QED bound states provide a simple toy model for investigating kinematically analogous situations in exclusive heavy hadronic decays in quantum chromodynamics, such as {ital B}{r_arrow}{ital K}{sup *}{gamma} or {ital B}{r_arrow}{pi}{ital e}{nu}.

  17. Radiocesium fluxes in rivers across the Fukushima fallout region to 2015 and their controlling factors

    NASA Astrophysics Data System (ADS)

    Onda, Yuichi; Taniguchi, Keisuke; Smith, Hugh; Blake, William; Yoshimura, Kazuya

    2016-04-01

    Due to Fukushima Daiichi Nuclear Power Plant accident, radioactive materials including Cs-134 and Cs-137 were widely distributed in surrounded area. The radiocesiums have been transported in river networks. The monitoring started at 6 sites from June 2011. Subsequently, additional 24 monitoring sites were installed between October 2012 and January 2013. Flow and turbidity were measured at each site in ten minite intervals, and suspended sediments and river water were collected every one or half month to measure Cs-134 and Cs-137 activity concentrations by gamma spectrometry. Fluxes of suspended sediment and radiocesium for the period up to October 2014 are summarised for both the longer-term monitoring stations. Fluxes were computed for monthly intervals. Small gaps in flow data were filled based on linear correlations with monthly data from nearby monitoring stations. Gaps in the suspended sediment load record were filled using L-Q (Load-Discharge) equations derived for each monitoring site based on monthly measurements between November 2012 and March 2015. Monthly L-Q equations were used in place of linear rating curves based on SSC-Q data collected at 10 minute intervals. The total measured flux to the ocean of radiocesium from the Abukuma River at Iwanuma was 14 TBq for the period from August 2011 to October 2014. The transfer of radiocesium with suspended sediment declining until March 2015 and had high correlation with land cover ratio by different land use of the catchments. Also we found positive correlation with radiocesium flux and catchment landuses.

  18. Radioactive contamination of pine (Pinus sylvestris) in Krasnoyarsk (Russia) following fallout from the Fukushima accident.

    PubMed

    Bolsunovsky, A; Dementyev, D

    2014-12-01

    Following the Fukushima accident in March 2011, samples of pine trees (Pinus sylvestris) were collected from three sites near the city of Krasnoyarsk (Siberia, Russia) during 2011-2012 and analyzed for artificial radionuclides. Concentrations of Fukushima-derived radionuclides in the samples of pine needles in April 2011 reached 5.51 ± 0.52 Bq kg(-1)(131)I, 0.92 ± 0.04 Bq kg(-1)(134)Cs, and 1.51 ± 0.07 Bq kg(-1)(137)Cs. An important finding was the detection of (134)Cs from the Fukushima accident not only in the pine needles and branches but also in the new shoots in 2012, which suggested a transfer of Fukushima cesium isotopes from branches to shoots. In 2011 and 2012, the (137)Cs/(134)Cs ratio for pine needles and branches collected in sampling areas Krasnoyarsk-1 and Krasnoyarsk-2 was greater than 1 (varying within a range of 1.2-2.6), suggesting the presence of "older", pre-Fukushima accident (137)Cs. Calculations showed that for pine samples growing in areas of the Krasnoyarskii Krai unaffected by contamination from the nuclear facility, the activity of the Fukushima-derived cesium isotopes was two-three times higher than the activity of the pre-accident (137)Cs.

  19. Radiocesium in Swedish reindeer after the Chernobyl fallout: Seasonal variations and long-term decline

    SciTech Connect

    Ahman, B.; Ahman, G.

    1994-05-01

    Data about {sup 137}Cs activity concentrations in reindeer muscle were collected from different parts of Sweden during 1986-1992. The data were used to evaluate seasonal and geographical variations and long-term decline of {sup 137}Cs in reindeer. The seasonal variation is shown in an example from one of the most contaminated areas, the Saami community Vilhelmina Norra, where {sup 137}Cs activity concentrations in reindeer during winter exceed those found during summer by about 20 times. Activity concentrations of {sup 137}Cs in reindeer were fairly well correlated to ground deposition. The ratio between {sup 137}Cs in reindeer (kBq kg{sup -1} wet weight) and ground deposition (kBq m{sup -2}) was calculated to be 0.76 m{sup 2} kg{sup -1} for the winter period, January-April, in 1987. Activity concentrations of {sup 137}Cs in reindeer decreased significantly during the years 1986-1992. The decline was generally more rapid during September, November, and December [corresponding to an effective ecological half-life (T{sub Eff}) of 3.2 y] than during January-April when T{sub Eff} was calculated to 4.2 y. There was a general trend toward a slower decrease during the last of the observed years. 42 refs., 5 figs., 2 tabs.

  20. Radiocesium in Swedish reindeer after the Chernobyl fallout: seasonal variations and long-term decline.

    PubMed

    Ahman, B; Ahman, G

    1994-05-01

    Data about 137Cs activity concentrations in reindeer muscle were collected from different parts of Sweden during 1986-1992. The data were used to evaluate seasonal and geographical variations and long-term decline of 137Cs in reindeer. The seasonal variation is shown in an example from one of the most contaminated areas, the Saami community Vilhelmina Norra, where 137Cs activity concentrations in reindeer during winter exceed those found during summer by about 20 times. Activity concentrations of 137Cs in reindeer were fairly well correlated to ground deposition. The ratio between 137Cs in reindeer (kBq kg-1 wet weight) and ground deposition (kBq m-2) was calculated to be 0.76 m2 kg-1 for the winter period, January-April, in 1987. Activity concentrations of 137Cs in reindeer decreased significantly during the years 1986-1992. The decline was generally more rapid during September, November, and December [corresponding to an effective ecological half-life (TEff) of 3.2 y] than during January-April when TEff was calculated to 4.2 y. There was a general trend toward a slower decrease during the last of the observed years.