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Sample records for fallout atom ratios

  1. Characterizing fallout material using Cs and Pu atom ratios in environmental samples from the FDNPP fallout zone

    NASA Astrophysics Data System (ADS)

    Richards, David; Dunne, James; Martin, Peter; Scott, Tom; Yamashiki, Yosuke; Coath, Chris; Chen, Hart

    2017-04-01

    Here we report the use of combined of Cs and Pu isotope measurements to investigate the extensive plumes of radioactive fallout from the disaster at Fukishima Daiichi nuclear power plant (FNDPP) in March 2011. Among the aims of our study are improved assessment of the physico-chemical nature and changing distribution of land-based fallout. 135Cs/137Cs and 134Cs/137Cs atom ratios are indicative of conditions that relate to the nuclear fission reactions responsible for producing the respective radiocaesium isotopes, and offer much more in terms of forensic and chronological analysis than monitoring 137Cs alone. We briefly present methods to quantify the atom ratios of Cs and Pu isotopes in soil, lichen and moss samples from FDNPP catchment using mass spectrometry (ThermoTRITON for Cs and ThermoNEPTUNE for Pu). High precision data from Fukushima are presented (e.g decay corrected 135Cs/137Cs atom ratio = 0.384 ± 0.001 (n = 5) for roadside dust from Iitate region), and these are in agreement with prelimary estimates by others. We also confirm results for IAEA-330, a spinach sample collected from Polesskoe, Ukraine and subject to contamination from the Chernobyl accident. In addition to Cs isotopes, we adopt Pu isotopes to add a further dimension to the forensic analysis. We discuss the corrections required for background levels prior to the disaster, possibility for multiple components of fallout and complicating factors associated with remobilisation during the clean-up operation. In parallel with this work on digests and leaches from bulk environmental samples, we are refining methods for particle identification, isolation and characterisation using a complementary sequence of cutting-edge materials and manipulation techniques, including combined electron microscopy, focused ion beam techniques (Dualbeam), nano/micro manipulators and nano-scale imaging x-ray photoelectron spectroscopy (NanoESCA) and microCT.

  2. Cancer mortality in residents of the terrain-shielded area exposed to fallout from the Nagasaki atomic bombing

    PubMed Central

    Mine, Mariko; Kondo, Hisayoshi; Matsuda, Naoki; Shibata, Yoshisada; Takamura, Noboru

    2018-01-01

    Abstract The health effects of radiation exposure from the atomic bomb fallout remain unclear. The objective of the present study is to elucidate the association between low-dose radiation exposure from the atomic bomb fallout and cancer mortality among Nagasaki atomic bomb survivors. Of 77 884 members in the Nagasaki University Atomic Bomb Survivors Cohort, 610 residents in the terrain-shielded area with fallout were selected for this analysis; 1443 residents in the terrain-shielded area without fallout were selected as a control group; and 3194 residents in the direct exposure area were also selected for study. Fifty-two deaths due to cancer in the terrain-shielded fallout area were observed during the follow-up period from 1 January 1970 to 31 December 2012. The hazard ratio for cancer mortality in the terrain-shielded fallout area was 0.90 (95% confidence interval: 0.65–1.24). No increase in the risk of cancer mortality was observed, probably because the dose of the radiation exposure was low for residents in the terrain-shielded fallout areas of the Nagasaki atomic bomb, and also because the number of study subjects was small. PMID:29036510

  3. Cancer mortality in residents of the terrain-shielded area exposed to fallout from the Nagasaki atomic bombing.

    PubMed

    Yokota, Kenichi; Mine, Mariko; Kondo, Hisayoshi; Matsuda, Naoki; Shibata, Yoshisada; Takamura, Noboru

    2018-01-01

    The health effects of radiation exposure from the atomic bomb fallout remain unclear. The objective of the present study is to elucidate the association between low-dose radiation exposure from the atomic bomb fallout and cancer mortality among Nagasaki atomic bomb survivors. Of 77 884 members in the Nagasaki University Atomic Bomb Survivors Cohort, 610 residents in the terrain-shielded area with fallout were selected for this analysis; 1443 residents in the terrain-shielded area without fallout were selected as a control group; and 3194 residents in the direct exposure area were also selected for study. Fifty-two deaths due to cancer in the terrain-shielded fallout area were observed during the follow-up period from 1 January 1970 to 31 December 2012. The hazard ratio for cancer mortality in the terrain-shielded fallout area was 0.90 (95% confidence interval: 0.65-1.24). No increase in the risk of cancer mortality was observed, probably because the dose of the radiation exposure was low for residents in the terrain-shielded fallout areas of the Nagasaki atomic bomb, and also because the number of study subjects was small. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  4. 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. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Resolving Nevada test site and global fallout plutonium in attic dust and soils using 137Cs/239+240Pu activity ratios.

    PubMed

    Cizdziel, J; Hodge, V; Faller, S

    1999-07-01

    A simple equation using only 137Cs/239+240Pu activity ratios was developed and evaluated as a means of resolving the plutonium in attic dust and soil from Nevada and Utah that came from Nevada Test Site fallout from that which came from global fallout. Applied to an historical data set of 137Cs and 239+240Pu activity concentrations in soils from Nevada and Utah, the activity ratio method gives results similar to the traditional 240Pu/239Pu isotope mass ratio method. Considering the difficulty and expense of determining the 240Pu/239Pu atom ratios, this activity ratio method is simpler, faster, and less costly, and may be useful for detecting and/or monitoring plutonium contamination in soils. Applied to samples of attic dust and soil collected from throughout southern Nevada and Utah during 1996 and 1997, it was found that all sites surveyed showed the presence of Nevada Test Site plutonium. Over 90% of the plutonium found in the samples from Beatty, Tonopah, and Queen City Summit, Nevada, can be attributed to the Nevada Test Site.

  6. 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.

  7. 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…

  8. DISTURBANCES OF SPERMATOGENESIS DUE TO RADIATION BY ATOMIC BOMB EXPLOSION AND FALL-OUT IN HIROSHIMA AND BIKINI

    SciTech Connect

    Murakami, N.

    1959-01-01

    Fifteen persons exposed to the atomic bomb in Hiroshima and 18 exposed to fall-out contamination in the Bikini area were examined for spermatogenesis. Three of the 15 Hiroshima cases showed aspermia and were believed not to have recovered, but all of the 18 Bikini cases showed complete recovery of spermatogenesis. Moat of the Bikini cases recovered in 9 to 20 months, but those which received 500 to 600 r of radiation took 30 months to recover. The physicochemical character of the sperm showed no great change in any of the cases. The function of the prostate was normal. (Abstr. Japanmore » Med., 1: No. 2, 1960)« less

  9. 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.

  10. 137Cs concentration in soil samples from an early survey of Hiroshima atomic bomb and cumulative dose estimation from the fallout.

    PubMed

    Shizuma, K; Iwatani, K; Hasai, H; Hoshi, M; Oka, T; Okano, M

    1996-09-01

    Low background gamma-ray measurement has been performed to determine the 137Cs content in soil samples collected in a very early survey of the Hiroshima atomic bomb. These soil samples were collected just 3 d after the explosion within 5 km from the hypocenter and were not exposed to the global fallout from nuclear weapon tests. Out of 22 samples, 137Cs was detected for 11 samples, and their radioactivities ranged from 0.16-10.6 mBq g-1 at the time of the measurement. A comparison of the 137Cs deposition with the rainfall area within Hiroshima city indicates that the rainfall area was wider than the previously proposed one. Cumulative exposure by the fallout has been estimated to be 0.31 mC kg-1 (0.12 R) in Hiroshima city except for the heavy fallout area and at most 1.0 mC kg-1 (4 R) in the heavy fallout area.

  11. 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

  12. 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).

  13. Transport of low 240Pu/ 239Pu atom ratio plutonium-species in the Ob and Yenisey Rivers to the Kara Sea

    NASA Astrophysics Data System (ADS)

    Lind, Ole Christian; Oughton, Deborah H.; Salbu, Brit; Skipperud, Lindis; Sickel, Morten A.; Brown, Justin E.; Fifield, L. Keith; Tims, Steven G.

    2006-11-01

    Plutonium (Pu) isotope ratios can be used to differentiate between sources of Pu contamination such as nuclear weapon production, weapon fallout as well as accidental and routine releases from nuclear installations. To obtain information on the contamination level, speciation and sources of Pu in the Ob and Yenisey river systems (Siberia, Russia) and the adjacent Kara Sea, water was size fractionated onboard ship and the concentrations and atom ratios of 240Pu and 239Pu in obtained water fractions (i.e. particles, colloids and low molecular mass species) were determined by accelerator mass spectrometry (AMS). Results show a clear difference in speciation between high 240Pu/ 239Pu atom ratio Pu derived from global weapon fallout and low 240Pu/ 239Pu atom ratio Pu, presumably originating from weapons grade Pu. In particular, the 240Pu/ 239Pu atom ratios (mean 0.18 ± 0.06) for particles (> 0.45 μm) could not be distinguished from global fallout Pu (0.17-0.19), whereas for low molecular mass (LMM; < 8 kDa) species the Pu ratio was much lower than for global fallout Pu in both rivers. The difference was especially well pronounced in the Ob (mean 240Pu/ 239Pu atom ratio 0.052 ± 0.023), where the difference was statistically significant (paired t-test, P = 0.02, n = 4). The low 240Pu/ 239Pu atom ratios in filtered (< 0.45 μm) water and especially in the LMM fractions were observed at stations along the whole length of the two sampling transects, extending from the lower parts of the Ob and Yenisey Rivers and into the northern Kara Sea. This provides evidence of long-range transport of Pu from low burn-up or non-civil sources into the Arctic Ocean. Pu appears to be predominantly in a dissolved form (< 0.45 μm) throughout the investigated area. The colloidal fraction (8 kDa-0.45 μm) ranged within 24-78% in the river systems and 8-53% in the Kara Sea. Concentrations of 239,240Pu in filtered (< 0.45 μm) water were very low, ranging from 2.6 to 40.6 mBq m - 3 in the

  14. Atomic bomb testing and its effects on global male to female ratios at birth.

    PubMed

    Grech, Victor

    2015-01-01

    Fallout from atomic bomb testing may travel great distances before precipitating. Males are born in excess of females in a ratio that approximates 0.515 (M/T: male live births divided by total live births. Radiation increases M/T by causing lethal malformations that affect female more than male foetuses, decreasing total births. This study was carried out in order to ascertain whether the effects of increased background radiation levels from atomic weapon testing had any widespread effects on M/T and births in the Americas, Europe, Asia and Australasia in relation to the Partial Test Ban Treaty of 1963. Annual live births by gender were obtained from a World Health Organization dataset and annual number of atomic bomb tests were also obtained (historical data). Overall, 94.5% of births studied showed a uniform reduction in M/T between the early 1950s to the late 1960s, followed by an increase to the mid-1970s, with a subsequent decline. A negative correlation of M/T with total births was found in 66% of births studied, and these were the regions which exhibited the rising M/T pattern in the 1970s. The birth deficit for countries with significant correlations of total births with M/T (North America, Europe and Asia) was estimated at 10090701. A rising M/T was found in most regions in temporal association with atomic weapon testing. Most of these regions also had an associated decline in total births. Elevated levels of man-made ambient radiation may have reduced total births, affecting pregnancies carrying female pregnancies more than those carrying male pregnancies, thereby skewing M/T toward a higher male proportion.

  15. 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

  16. 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.

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

    PubMed

    Putz, Mihai V

    2012-11-12

    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. 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. 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).

  18. 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

  19. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Riparian forest potential to retain sediment and carbon evaluated by the 137Cs fallout and carbon isotopic ratio techniques.

    PubMed

    Pires, Luiz F; Bacchi, Osny O S; Correchel, Vladia; Reichardt, Klaus; Filippe, Joseline

    2009-06-01

    Riparian forests can provide an important service for aquatic ecosystems by sequestering hillslopederived sediments. However, the width of a riparian buffer zone required to filter sediments is not yet wellunderstood. Here are used two complementary tracers to measure sediment retention. The 137Cs technique and the soil carbon isotopic ratios (delta13C) are utilized to investigate sediment deposition and erosion rates on a slope transect cultivated with sugarcane followed by a secondary riparian forest zone in Iracemápolis, State of São Paulo, Brazil. The 137Cs technique and the delta13C analysis showed that the width of a riparian vegetation in accordance to a Brazilian Environmental Law (N masculine4.771/65) was not sufficient in trapping sediments coming from agricultural lands, but indicated the importance of these forests as a conservation measure at the watershed scale. The complementary delta13C analysis together with soil morphology aspects allowed a better interpretation of the sediment redistribution along the sugarcane and riparian forest transects.

  1. Pu fallout across continental Australia: Implications on239Pu use as a soil tracer.

    PubMed

    Lal, R; Fifield, L K; Tims, S G; Wasson, R J

    2017-11-01

    At present there is a need for the development of new radioisotopes for soil erosion and sediment tracing especially as fallout 137 Cs levels become depleted. Recent studies have shown that 239 Pu can be a useful new soil erosion and sediment radioisotope tracer. 239 Pu was released in the major atmospheric nuclear weapons tests of 1950's and 1960's. However 239 Pu has a half-life of 24110 years and more than 99% of this isotope is still present in the environment today. In contrast 137 Cs with a half-life of 30.07 year has decayed to <35% of initially deposited activities and this isotope will become increasingly difficult to measure in the coming decades especially in the southern hemisphere, which received only about a third of the total global fallout from the atmospheric tests (UNSCEAR, 2000). In this study an assessment of the 239 Pu fallout in Australia was carried out from comparison of measured 239 Pu inventories with expected 239 Pu inventories from fallout models. 239 Pu inventories were also compared with rainfall and measured 240 Pu/ 239 Pu ratios across Australia. 239 Pu fallout inventories ranged from 430 to 1461 μB/cm 2 . Central Australia, with fallout 107% in excess of expected values, seems to be strongly impacted by local fallout deposition. In comparison other sites typically show 5-40% variation between expected and measured fallout values. The fallout inventories were found to weakly correlate (using power functions, y = ax b ) with rainfall with r 2  = 0.50 across the southern catchments (25-40°S latitude band). Across the northern catchments (10-25°S latitude band) fallout showed greater variability with rainfall with r 2  = 0.24. Central Australia and Alice Springs which seem to be strongly impacted by local fallout are excluded from the rainfall correlation data (with these sites included r 2  = 0.08 and r 2  < 0.01 respectively). 240 Pu/ 239 Pu atom ratios range from 0.045 to 0.197, with averages of 0.139(0.017), 0

  2. Bounding Analysis of Effects of Fractionation of Radionuclides inFallout on Estimation of Doses to Atomic Veterans

    DTIC Science & Technology

    2007-05-04

    produced in four fission modes as a function of decay time, exposure pathway, and assumed yields of activation products 37 4 Adjusted fractionation ratios...doses from inhalation or ingestion, which give a sum of weighted equivalent doses in various organs and tissues of the body ( ICRP 1991). Doses to...weapons conducted during Operation PLUMBBOB in 1957 [BOLTZMANN (12 kt), FRANKLIN (0.14 kt), PRISCILLA ( 37 kt), and WILSON (10 kt)] suggest that the

  3. Non-thyroid cancer incidence in Belarusian residents exposed to Chernobyl fallout in childhood and adolescence: Standardized Incidence Ratio analysis, 1997-2011.

    PubMed

    Ostroumova, Evgenia; Hatch, Maureen; Brenner, Alina; Nadyrov, Eldar; Veyalkin, Ilya; Polyanskaya, Olga; Yauseyenka, Vasilina; Polyakov, Semion; Levin, Leonid; Zablotska, Lydia; Rozhko, Alexander; Mabuchi, Kiyohiko

    2016-05-01

    While an increased risk of thyroid cancer from post-Chernobyl exposure to Iodine-131 (I-131) in children and adolescents has been well-documented, risks of other cancers or leukemia as a result of residence in radioactively contaminated areas remain uncertain. We studied non-thyroid cancer incidence in a cohort of about 12,000 individuals from Belarus exposed under age of 18 years to Chernobyl fallout (median age at the time of Chernobyl accident of 7.9 years). During 15 years of follow-up from1997 through 2011, 54 incident cancers excluding thyroid were identified in the study cohort with 142,968 person-years at risk. We performed Standardized Incidence Ratio (SIR) analysis of all solid cancers excluding thyroid (n=42), of leukemia (n=6) and of lymphoma (n=6). We found no significant increase in the incidence of non-thyroid solid cancer (SIR=0.83, 95% Confidence Interval [CI]: 0.61; 1.11), lymphoma (SIR=0.66, 95% CI: 0.26; 1.33) or leukemia (SIR=1.78, 95% CI: 0.71; 3.61) in the study cohort as compared with the sex-, age- and calendar-time-specific national rates. These findings may in part reflect the relatively young age of study subjects (median attained age of 33.4 years), and long latency for some radiation-related solid cancers. We found no evidence of statistically significant increases in solid cancer, lymphoma and leukemia incidence 25 years after childhood exposure in the study cohort; however, it is important to continue follow-up non-thyroid cancers in individuals exposed to low-level radiation at radiosensitive ages. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Non-thyroid cancer incidence in Belarusian residents exposed to Chernobyl fallout in childhood and adolescence: Standardized Incidence Ratio analysis, 1997–2011

    PubMed Central

    Ostroumova, Evgenia; Hatch, Maureen; Brenner, Alina; Nadyrov, Eldar; Veyalkin, Ilya; Polyanskaya, Olga; Yauseyenka, Vasilina; Polyakov, Semion; Levin, Leonid; Zablotska, Lydia; Rozhko, Alexander; Mabuchi, Kiyohiko

    2016-01-01

    Background While an increased risk of thyroid cancer from post-Chernobyl exposure to Iodine-131 (I-131) in children and adolescents has been well-documented, risks of other cancers or leukemia as a result of residence in radioactively contaminated areas remain uncertain. Methods We studied non-thyroid cancer incidence in a cohort of about 12,000 individuals from Belarus exposed under age of 18 years to Chernobyl fallout (median age at the time of Chernobyl accident of 7.9 years). During 15 years of follow-up from1997 through 2011, 54 incident cancers excluding thyroid were identified in the study cohort with 142,968 person-years at risk. We performed Standardized Incidence Ratio (SIR) analysis of all solid cancers excluding thyroid (n=42), of leukemia (n=6) and of lymphoma (n=6). Results We found no significant increase in the incidence of non-thyroid solid cancer (SIR=0.83, 95% Confidence Interval [CI]: 0.61; 1.11), lymphoma (SIR=0.66, 95% CI: 0.26; 1.33) or leukemia (SIR=1.78, 95% CI: 0.71; 3.61) in the study cohort as compared with the sex-, age- and calendar-time-specific national rates. These findings may in part reflect the relatively young age of study subjects (median attained age of 33.4years), and long latency for some radiation-related solid cancers. Conclusions We found no evidence of statistically significant increases in solid cancer, lymphoma and leukemia incidence 25 years after childhood exposure in the study cohort; however, it is important to continue follow-up non-thyroid cancers in individuals exposed to low-level radiation at radiosensitive ages. PMID:26851723

  5. 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

  6. Lead concentrations and isotope ratios in street dust determined by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry.

    PubMed

    Nageotte, S M; Day, J P

    1998-01-01

    A major source of environmental lead, particularly in urban areas, has been from the combustion of leaded petrol. Street dust has previously been used to assess urban lead contamination, and the dust itself can also be a potential source of lead ingestion, particularly to children. The progressive reduction of lead in petrol, in recent years, would be expected to have been reflected in a reduction of lead in urban dust. We have tested this hypothesis by repeating an earlier survey of Manchester street dust and carrying out a comparable survey in Paris. Samples were collected from streets and parks, lead was extracted by digestion with concentrated nitric acid and determined by electrothermal atomic absorption spectrometry. Lead isotope ratios were measured by inductively coupled plasma mass spectrometry. Results for Manchester show that lead concentrations have fallen by about 40% (street dust averages, 941 micrograms g-1 (ppm) in 1975 down to 569 ppm in 1997). In Paris, the lead levels in street dust are much higher and significant differences were observed between types of street (not seen in Manchester). Additionally, lead levels in parks were much lower than in Manchester. Samples collected under the Eiffel Tower had very high concentrations and lead isotope ratios showed that this was unlikely to be fallout from motor vehicles but could be due to the paint used on the tower. Isotope ratios measurements also revealed that lead additives used in France and the UK come from different sources.

  7. Strontium 90 fallout prediction

    NASA Astrophysics Data System (ADS)

    Sarmiento, Jorge L.; Gwinn, Elisabeth

    1986-06-01

    An empirical formula is developed for predicting monthly sea level strontium 90 fallout (F) in the northern hemisphere as a function of time (t), precipitation rate (P), latitude (ϕ), longitude (λ), and the sea level concentration of strontium 90 in air (C): F(λ, ϕ, t) = C(t, ϕ)[νd(ϕ) + νw(λ, ϕ, t)], where νw(λ, ϕ, t) = a(ϕ)[P(λ, ϕ, t)/P0]b(ϕ) is the wet removal, νd(ϕ) is the dry removal and P0 is 1 cm/month. The constants νd, a, and b are determined as functions of latitude by fitting land based observations. The concentration of 90Sr in air is calculated as a function of the deseasonalized concentration at a reference latitude ?, the ratio of the observations at the latitude of interest to the reference latitude (R), and a function representing the seasonal trend in the air concentration ? is the month. Zonal trends in C are shown to be relatively small. This formula can be used in conjunction with precipitation observations and/or estimates to predict fallout in the northern hemisphere for any month in the years 1954 to 1974. Error estimates are given; they do not include uncertainty due to errors in precipitation data. The cumulative North Atlantic 90Sr input predicted by the model for 1.25°N to 66.25°N decay corrected to December 1972 is ?, compared to an inventory estimate of ? from oceanic observations. It is suggested that the discrepancy is due to a more efficient scavenging of small particles over the oceans than over land.

  8. 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.

  9. 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.

  10. Estimates of doses from global fallout.

    PubMed

    Bouville, André; Simon, Steven L; Miller, Charles W; Beck, Harold L; Anspaugh, Lynn R; Bennett, Burton G

    2002-05-01

    This paper summarizes information about external and internal doses resulting from global fallout and presents preliminary estimates of doses resulting from intermediate fallout in the contiguous United States. Most of the data on global fallout were extracted from the reports of the United Nations Scientific Committee on the Effects of Atomic Radiation, in which the radiation exposures from fallout have been extensively reviewed at regular intervals. United Nations Scientific Committee on the Effects of Atomic Radiation estimated the average effective doses received by the world's population before 2000 to be about 0.4 mSv from external irradiation and 0.6 mSv from internal irradiation, the main radionuclide contributing to the effective dose being 137Cs. Effective doses received beyond 2000 result mainly from the environmentally mobile, long-lived 14C and amount to about 2.5 mSv summed over present and future generations. Specific information about the doses from fallout received by the United States population is based on the preliminary results of a study requested by the U.S. Congress and conducted jointly by the Centers for Disease Control and Prevention and the National Cancer Institute. Separate calculations were made for the tests conducted at the Nevada Test Site and for the high-yield tests conducted mainly by the United States and the former Soviet Union at sites far away from the contiguous United States (global tests). The estimated average doses from external irradiation received by the United States population were about 0.5 mGy for Nevada Test Site fallout and about 0.7 mGy for global fallout. These values vary little from one organ or tissue of the body to another. In contrast, the average doses from internal irradiation vary markedly from one organ or tissue to another; estimated average thyroid doses to children born in 1951 were about 30 mGy from Nevada Test Site fallout and about 2 mGy from global fallout.

  11. Plutonium isotope ratio variations in North America

    SciTech Connect

    Steiner, Robert E; La Mont, Stephen P; Eisele, William F

    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 altersmore » 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.« less

  12. Fallout Radioactivity and Epiphytes.

    Treesearch

    H. T. Odum; George Ann Briscoe; C. B. Briscoe

    1970-01-01

    After relatively high levels of fallout retention were dicovered in the epiphytic mossy forest of the Luquillo Mountains durin 1962, a survey of the distribution of radioactivity in the rain forest system was made with beta counting of 1500 samples supplemented with gamma spectra. High levels, up to 4138 counts per minute per gram, were found mainly in or on green...

  13. Procedures for precise measurements of 135Cs/137Cs atom ratios in environmental samples at extreme dynamic ranges and ultra-trace levels by thermal ionization mass spectrometry.

    PubMed

    Dunne, James A; Richards, David A; Chen, Hsin-Wei

    2017-11-01

    Determination of 135Cs/137Cs atom ratios has the potential to be a powerful tool for nuclear forensics and monitoring environmental processes. We present optimized chemical separation techniques and thermal ionization mass spectrometry (TIMS) protocols to obtain precise 135Cs/137Cs atom ratios for a range of environmental sample types. We use a combination of double AMP-PAN separation and Sr-spec resin column purification to yield excellent separation from the alkali metals (Rb separation factor > 600), which normally suppress ionization of Cs. A range of emission activators for the ionization of Cs were evaluated and glucose solution yielded the optimal combination of a stable Cs+ beam, minimal low-temperature polyatomic interferences and improved ionization efficiency. Mass-spectrometric determination of low abundance 135Cs and 137Cs is compromised by the presence of a very large 133Cs+ beam, which may be scattered and cause significant spectral interferences. These are explored using multi-static Faraday cup - ion counter methods and a range of energy filter settings. The method is evaluated using environmental samples and standards from regions affected by fallout from Chernobyl (IAEA-330) and Fukushima nuclear disasters. Where the intensity of 133Cs+ is large relative to 135Cs+ and 137Cs+ (< 30cps), minor polyatomic interferences need to be considered. In the absence of a standard with 135, 137Cs/133Cs < 1 × 10-8, we explored the reproducibility of 135Cs/137Cs atom ratios at these high dynamic ranges and extremely low abundance (137Cs ≈ 12 fg g-1) for sediments from an estuarine setting in SW England, UK. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  14. THE PHYSICIAN AND FALLOUT

    SciTech Connect

    Charles, S.

    1962-10-01

    Criticisms are advanced against official attitudes and statements which are alleged to minimize the effects of fallout on present and future populations, and the responsibilities of the physician in assessing somatic and genetic effects of fallout are discussed. It is proposed that there has been a remarkable and uniform silence from practically all segments of American medicine regarding any possible health hazard from fallout, and that whenever a statement is issued, it is usually prepared to dilute an concern. It is suggested that many physicians have thought that there is no problem, and others have assumed that only authorities withmore » access to confidential and specialized information can arrive at any intelligent conclusions. Lack of knowledg of the possible deleterious effects of fallout radionuclides is emphasized, and it is pointed out that some nuclides with short half lives, other than those generally considered to be most hazardous, may contribute over half of the background radiation. Standards on the determination of minimum permissible levels are considered. It is suggested that in considering genetic effects the many statements of the absence of genetic effects in radiation-exposed populations of Hiroshima and Nagasaki should be examined. Hazards of high levels of /sup 131/I in milk are emphasized, and possible preventive steps weighed. It is concluded that physicians should participnte in programs of information and education to both professional and lay groups, and that there will be less confusion and complacency when the American medical profession better understands the challenge involved in radiological health. (BBB)« less

  15. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. 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.

    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, radionuclidemore » 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.« less

  17. Anthropogenic 236U in Danish Seawater: Global Fallout versus Reprocessing Discharge.

    PubMed

    Qiao, Jixin; Steier, Peter; Nielsen, Sven; Hou, Xiaolin; Roos, Per; Golser, Robin

    2017-06-20

    This work focuses on the occurrence of 236U in seawater along Danish coasts, which is the sole water-exchange region between the North Sea-Atlantic Ocean and the Baltic Sea. Seawater collected in 2013 and 2014 were analyzed for 236U (as well as 238U and 137Cs). Our results indicate that 236U concentrations in Danish seawater are distributed within a relatively narrow range of (3.6-8.2) × 107 atom/L and, to a certain extent, independent of salinity. 236U/238U atomic ratios in Danish seawater are more than 4 times higher than the estimated global fallout value of 1× 10-9. The levels of 236U/238U atomic ratios obtained are comparable to those reported for the open North Sea and much higher than several other open oceans worldwide. This indicates that besides the global fallout input, the discharges from the two major European nuclear reprocessing plants are dominating sources of 236U in Danish seawater. However, unexpectedly high 236U/238U ratios as well as high 236U concentrations were observed at low-salinity locations of the Baltic Sea. While this feature might be interpreted as a clue for another significant 236U input in the Baltic Sea, it may also be caused by the complexity of water currents or slow turnover rate.

  18. Tables of branching ratios for electric dipole transitions between arbitrary levels of hydrogen-like atoms

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1977-01-01

    The branching ratios in hydrogen-like atoms due to the electric-dipole transitions are tabulated for the initial principal and azimuthal quantum numbers n prime l prime, and final principal and azimuthal quantum numbers n l. Average values with respect to l prime are given. The branching ratios not tabulated, including the initial states n prime yields infinity l prime corresponding to the threshold of the continuum, could be obtained by extrapolation.

  19. Rate-equation approach to optimal density ratio of K-Rb hybrid cells for optically pumped atomic magnetometers.

    PubMed

    Ito, Yosuke; Ohnishi, Hiroyuki; Kamada, Keigo; Kobayashi, Tetsuo

    2013-01-01

    The goal of this study is to determine optimal conditions of optically pumped atomic magnetometers using a hybrid cell of potassium and rubidium atoms. We theoretically investigated the properties of the magnetometers and considered the optimal density ratio of potassium and rubidium atoms. We found that the experimental results agreed well with the theoretical estimations and the density ratio of potassium and rubidium atoms should be around 200 to achieve the highest sensitivity.

  20. The ratio of molecular to atomic gas in spiral galaxies as a function of morphological type

    NASA Technical Reports Server (NTRS)

    Knezek, Patricia M.; Young, Judith S.

    1990-01-01

    In order to gain an understanding of the global processes which influence cloud and star formation in disk galaxies, it is necessary to determine the relative amounts of atomic, molecular, and ionized gas both as a function of position in galaxies and from galaxy to galaxy. With observations of the CO distributions in over 200 galaxies now completed as part of the Five College Radio Astronomy Observatory (FCRAO) Extragalactic CO Survey (Young et al. 1989), researchers are finally in a position to determine the type dependence of the molecular content of spiral galaxies, along with the ratio of molecular to atomic gas as a function of type. Do late type spirals really have more gas than early types when the molecular gas content is included. Researchers conclude that there is more than an order of magnitude decrease in the ratio of molecular to atomic gas mass as a function of morphological type from Sa-Sd; an average Sa galaxy has more molecular than atomic gas, and an average Sc has less. Therefore, the total interstellar gas mass to blue luminosity ratio, M sub gas/L sub B, increases by less than a factor of two as a function of type from Sa-Sd. The dominant effect found is that the phase of the gas in the cool interstellar medium (ISM) varies along the Hubble sequence. Researchers suggest that the more massive and centrally concentrated galaxies are able to achieve a molecular-dominated ISM through the collection of more gas in the potential. That gas may then form molecular clouds when a critical density is exceeded. The picture which these observations support is one in which the conversion of atomic gas to molecular gas is a global process which depends on large scale dynamics (cf Wyse 1986). Among interacting and merging systems, researchers find considerable scatter in the M(H2)/M(HI) ratio, with the mean ratio similar to that in the early type galaxies. The high global ratio of molecular to atomic gas could result from the removal of HI gas, the enhanced

  1. 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

  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 gainedmore » 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.« less

  3. Rapid processing of 85Kr/Kr ratios using Atom Trap Trace Analysis

    SciTech Connect

    Zappala, J. C.; Bailey, K.; Mueller, P.

    2017-03-11

    In this paper, we report a methodology for measuring 85Kr/Kr isotopic abundances using Atom Trap Trace Analysis (ATTA) that increases sample measurement throughput by over an order of magnitude to six samples per 24 h. The noble gas isotope 85Kr (half-life = 10.7 years) is a useful tracer for young groundwater in the age range of 5–50 years. ATTA, an efficient and selective laser-based atom counting method, has recently been applied to 85Kr/Kr isotopic abundance measurements, requiring 5–10 μL of krypton gas at STP extracted from 50 to 100 L of water. Previously, a single such measurement required 48 h.more » In conclusion, our new method demonstrates that we can measure 85Kr/Kr ratios with 3–5% relative uncertainty every 4 h, on average, with the same sample requirements.« less

  4. Rapid processing of 85Kr/Kr ratios using Atom Trap Trace Analysis

    SciTech Connect

    Zappala, J. C.; Bailey, K.; Mueller, P.; O'Connor, T. P.; Purtschert, R.

    2017-03-11

    In this paper, we report a methodology for measuring 85Kr/Kr isotopic abundances using Atom Trap Trace Analysis (ATTA) that increases sample measurement throughput by over an order of magnitude to six samples per 24 h. The noble gas isotope 85Kr (half-life = 10.7 years) is a useful tracer for young groundwater in the age range of 5–50 years. ATTA, an efficient and selective laser-based atom counting method, has recently been applied to 85Kr/Kr isotopic abundance measurements, requiring 5–10 μL of krypton gas at STP extracted from 50 to 100 L of water. Previously, a single such measurement required 48 h. In conclusion, our new method demonstrates that we can measure 85Kr/Kr ratios with 3–5% relative uncertainty every 4 h, on average, with the same sample requirements.

  5. Optimization of metal atomic ratio of PdxRuyNiz on carbon support for ethanol oxidation

    NASA Astrophysics Data System (ADS)

    Charoen, Kanin; Warakulwit, Chompunuch; Prapainainar, Chaiwat; Seubsai, Anusorn; Chareonpanich, Metta; Prapainainar, Paweena

    2017-11-01

    The catalytic activity of palladium (Pd) on an alloy catalyst on carbon supports with regards to ethanol oxidation was enhanced by systematically varying the atomic ratio of Pd, ruthenium (Ru), and nickel (Ni) alloy catalyst. Each atomic ratio catalyst was investigated so as to find the highest current density per mass of palladium. Functionalized carbon black (C) and reduced graphene oxide (rGO) were used as carbon supports. The PdxRuyNiz/carbon catalysts were prepared by impregnation and reduction method with sodium borohydride (NaBH4) being used as the reducing agent. Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) were used to characterize the functionalized carbon supports, and the synthesized PdxRuyNiz/carbon catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and inductively coupled plasma (ICP). The electrical properties of catalyst were performed by cyclic voltammetry (CV), chronoamperometry (CA), and CO-stripping to investigate the catalytic activity compared to 20%wt synthesized Pd/C. The results showed that Pd:Ru:Ni = 60:0:40 on rGO (Pd60Ni40/rGO) had the best metal atomic ratio and support for the electro-oxidation of ethanol. The maximum current density and the electrochemical surface area were 11,074 mA cm-2 mg-1Pd and 55.6 m2 g-1Pd, which were 1.7 and 2.67 times the corresponding values of synthesized Pd/C, respectively.

  6. Iridium isotope ratio measurements by negative thermal ionization mass spectrometry and atomic weight of iridium

    NASA Astrophysics Data System (ADS)

    Walczyk, Thomas; Heumann, Klaus G.

    1993-02-01

    A technique of negative thermal ionization mass spectrometry (NTI-MS) for the precise iridium isotope ratio determination is presented. IrO-2 and IrO-3 ions are formed in a double-filament (Pt) ion source using (NH4)2IrCl6 as a sample compound. The IrO-2 ion current always exceeds the IrO-3 current by a factor of about 50-300 depending on the filament temperature and the oxygen gas introduced into the ion source. IrO-3 ion currents of more than 10-11 A can be obtained at the detector side from 100 ng iridium samples. The relative standard deviation of the 191Ir/193 ratio determination is 0.06%, which is much better than the data quoted in past literature. From such data the atomic weight of iridium could be calculated to be 192.21661 ± 0.00029. This value is a great improvement when compared with the iridium atomic weight of 192.22 ± 0.03 recommended by IUPAC. Additionally, an NTI-MS technique has been developed which allows the simultaneous measurement of iridium and osmium isotope ratio from osmiridium samples without any chemical separation. The iridium isotope ratios of three osmiridium samples agree well with the ratios determined from the hexachloroiridate compound. The direct 187Os/186OS determination from osmiridium samples opens the possibility of studying the evolution of osmium in the Earth's mantle due to the radioactive decay of 187Re into 187Os.

  7. 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.

  8. 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…

  9. 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.

  10. Effects of V/III ratio on ordering in GaInP: Atomic scale mechanisms

    NASA Astrophysics Data System (ADS)

    Chun, Y. S.; Murata, H.; Hsu, T. C.; Ho, I. H.; Su, L. C.; Hosokawa, Y.; Stringfellow, G. B.

    1996-05-01

    Ga0.5In0.5P layers have been grown by organometallic vapor-phase epitaxy using various values of input V/III ratio for two phosphorus precursors, phosphine, the conventional precursor, and tertiarybutylphosphine (TBP), a newly developed, less-hazardous precursor. For growth on nominally (001) GaAs substrates misoriented by 3° (and in some cases by 0° or 6°) to produce [110] steps on the surface at a growth temperature of 620 °C, the Cu-Pt-type ordering is found to be strongly affected by the input flow rate of the phosphorus precursor (V/III ratio). For decreasing input partial pressures below 3 Torr for PH3 and 0.75 Torr for TBP the low-temperature photoluminescence (PL) peak energy increases indicating a lower degree of order. This is confirmed by transmission electron diffraction results. The decrease in the degree of order corresponds to a decrease in the concentration of [1¯10]-oriented P dimers on the surface, as indicated by surface photoabsorption spectroscopy results. These data indicate that the reduction in ordering is caused by the loss of the (2×4) reconstructed surface during growth. The difference in the behavior for PH3 and TBP is interpreted as due to the lower pyrolysis efficiency of PH3. The surface structure measured using high-resolution atomic force microscopy indicates that the [110] steps produced by the intentional misorientation of the substrate are bunched to produce supersteps approximately 30-40 Å in height for the lowest V/III ratios. The step height decreases markedly as the input phosphorus partial pressure increases from 0.4 to 0.75 Torr for TBP and from 1 to 3 Torr for PH3. This corresponds to a change from mainly monolayer to predominantly bilayer steps in the vicinal regions between bunched supersteps. Stabilization of the bilayer steps is interpreted as due to formation of the (2×2) reconstruction on the (111)B step edges. The degree of order is an inverted U-shaped function of the flow rate of the phosphorus precursor

  11. Effective Medium Ratio Obeying Wideband Left-Handed Miniaturized Meta-atoms for Multi-band Applications

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad Jakir; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2018-03-01

    In this paper, a miniaturized wideband left-handed (LH) meta-atom based on planar modified multiple hexagonal split ring resonators was designed, simulated, fabricated and tested that can maintain a left-handed property. An analysis and comparison of the different array structures were performed that obtained better effective medium ratio (EMR) and wideband (5.54 GHz) for multi band operations in the microwave regime. Finite-difference time-domain (FDTD) method based Computer Simulation Technology was implemented to design the meta-atom. The meta-atom showed multi-band response in conjunction with wideband and LH property over the certain frequency bands in the microwave spectra. The EMR was considerably improved compared to previously reported meta-atoms. The measured results showed good agreement with the simulated results. The dimensions, S-parameters and EMR parameters of the proposed miniaturized LH meta-atom are appropriate for L-, S-, C-, X-, and Ku-band applications.

  12. Effective Medium Ratio Obeying Wideband Left-Handed Miniaturized Meta-atoms for Multi-band Applications

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad Jakir; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2017-12-01

    In this paper, a miniaturized wideband left-handed (LH) meta-atom based on planar modified multiple hexagonal split ring resonators was designed, simulated, fabricated and tested that can maintain a left-handed property. An analysis and comparison of the different array structures were performed that obtained better effective medium ratio (EMR) and wideband (5.54 GHz) for multi band operations in the microwave regime. Finite-difference time-domain (FDTD) method based Computer Simulation Technology was implemented to design the meta-atom. The meta-atom showed multi-band response in conjunction with wideband and LH property over the certain frequency bands in the microwave spectra. The EMR was considerably improved compared to previously reported meta-atoms. The measured results showed good agreement with the simulated results. The dimensions, S-parameters and EMR parameters of the proposed miniaturized LH meta-atom are appropriate for L-, S-, C-, X-, and Ku-band applications.

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

    DTIC Science & Technology

    1985-09-01

    From the assumption that the ratio at early times In all cases is 1, Interpretation of these figures in terms of fallout distribution indicates that 90 ...0.23 Massive R3 8 0.82 0.56 Massi"e R4 10 0.82 0." Masaive R5 12 0.78 0.55 R, [0( 90 )]FO: [RIG9 0 ) ]E Ratio of Sr" to Moe observed in fallout Ratio of...VALUES, OPERATION REDWING R"( 90 ) R"(137) Shot Cloud Average Average Fallout Fallout Flathead -1.1 0.34 -2.3 0.32 Navajo - 0.8 - 0.7 Tewa -1.0 0.29 ’ -1.5

  14. 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

  15. 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. Copyright © 2013 Wiley Periodicals, Inc.

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

    SciTech Connect

    Burke, Micheal, E-mail: micheal.burke@tyndall.ie; Blake, Alan; Djara, Vladimir

    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{supmore » 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.« less

  17. Nuclear Fallout Decision Tool for First Responders

    SciTech Connect

    Archibald, E. J.; Buddemeier, B. R.

    2010-08-11

    If terrorists detonated an improvised nuclear device (IND) in an urban area, thousands of people would die from the blast, and many more would become sick or die from exposure to fallout radiation. Proper sheltering and evacuation can protect people from fallout and save lives. This project provides guidance to first responders as to when to evacuate and what route to take to protect themselves against fallout radiation.

  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. 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

  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. 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.

  2. Influence of the ion/neutral atom mass ratio on the damping of electrostatic ion-cyclotron waves

    NASA Technical Reports Server (NTRS)

    Suszcynsky, D. M.; Cartier, S. L.; D'Angelo, N.; Merlino, R. L.

    1987-01-01

    The damping of electrostatic ion-cyclotron waves by ion-neutral collisions was studied in a single-ended Q machine. The amplitudes of K(+) and Cs(+) electrostatic ion-cyclotron waves were measured as a function of neutral pressure in helium, neon, argon, krypton, and xenon. For each ion/neutral atom combination, the electrostatic ion-cyclotron wave amplitude maximizes at a neutral pressure that scales monotonically with the m(+)/m(n) mass ratio. This result is interpreted by considering the dynamics of elastic collisions between the ions and the neutral atoms.

  3. Some meteorological applications of radioactive fallout measurements in Antarctic snows

    NASA Astrophysics Data System (ADS)

    Pourchet, M.; Pinglot, F.; Lorius, C.

    1983-07-01

    Radioactive fallout measurements, generally performed to determine average snow accumulation rates, can also be used to determine other meteorological information. The following results were obtained from measurements on the Antarctic ice sheet: (1) A strasospheric residence time of 1.5 years for radioisotopes such as 90Sr and 137Cs. (2) A value of approximatively 1 of the ratio ϕ between the concentration measured, in the air (g/m3 STP) and the concentration determined in the snow (g/g), with extreme values of 0.5 and 5. (3) The dry fallout represents between 15 and 25% of the total deposition in the coastal regions and as much as 40 to 60% in the central zones. (4) A precipitation increase of 30% occured after 1965 when compared with the decade 1955-1965.

  4. 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. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. 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.

  6. 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.

  7. 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).

  8. 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…

  9. Building Protection Against External Ionizing Fallout Radiation

    SciTech Connect

    Dillon, Michael B.; Homann, Steven G.

    2016-12-01

    A nuclear explosion has the potential to injure or kill tens to hundreds of thousands of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing external radiation exposures) by placing material and distance between fallout particles and indoor individuals. This protection is not well captured in current fallout risk assessment models and so the US Department of Defense is implementing the Regional Shelter Analysis methodology to improve the ability of the Hazard Prediction and Assessment Capability (HPAC) model to account for building protection. This report supports the HPAC improvement effort by identifying a set of building attributes (next page) that, when collectively specified, are sufficient to calculate reasonably accurate, i.e., within a factor of 2, fallout shelter quality estimates for many individual buildings. The set of building attributes were determined by first identifying the key physics controlling building protection from fallout radiation and then assessing which building attributes are relevant to the identified physics. This approach was evaluated by developing a screening model (PFscreen) based on the identified physics and comparing the screening model results against the set of existing independent experimental, theoretical, and modeled building protection estimates. In the interests of transparency, we have developed a benchmark dataset containing (a) most of the relevant primary experimental data published by prior generations of fallout protection scientists as well as (b) the screening model results.

  10. Building Protection Against External Ionizing Fallout Radiation

    SciTech Connect

    Dillon, Michael B.; Homann, Steven G.

    2016-12-01

    A nuclear explosion has the potential to injure or kill tens to hundreds of thousands of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing external radiation exposures) by placing material and distance between fallout particles and indoor individuals. This protection is not well captured in current fallout risk assessment models and so the US Department of Defense is implementing the Regional Shelter Analysis methodology to improve the ability of the Hazard Prediction and Assessment Capability (HPAC) model to account for building protection. This report supports the HPAC improvement effort by identifying a setmore » of building attributes (next page) that, when collectively specified, are sufficient to calculate reasonably accurate, i.e., within a factor of 2, fallout shelter quality estimates for many individual buildings. The set of building attributes were determined by first identifying the key physics controlling building protection from fallout radiation and then assessing which building attributes are relevant to the identified physics. This approach was evaluated by developing a screening model (PFscreen) based on the identified physics and comparing the screening model results against the set of existing independent experimental, theoretical, and modeled building protection estimates. In the interests of transparency, we have developed a benchmark dataset containing (a) most of the relevant primary experimental data published by prior generations of fallout protection scientists as well as (b) the screening model results.« less

  11. Double-to-single photoionization ratio of plasma-embedded helium atom at X-ray energies

    NASA Astrophysics Data System (ADS)

    Kar, Sabyasachi; Ho, Yew Kam

    2008-05-01

    The double photoionization of helium by absorption of a high-frequency photon have gained considerable interest in theoretical [1-2] and experimental [3] studies during the last decades. In this work, we have investigated the asymptotic ratios of double-to-single photoionization of plasmas-embedded helium atom at very high photon but non-relativistic energies in the framework of the Debye model for weakly coupled plasmas [4]. The ratio of double-to-single photoionization for free atom is determined as 1.644%, in good agreement with the synchrotron measurements [3] and other theoretical predictions [1, 2]. The asymptotic ratio of double-to-single photoionization cross-sections for different screening parameters along with the single, the double, and the total photoionization asymptotic cross sections will be presented at the meeting. [1] R. C. Forrey, et al., Phys. Rev. A 51, 2112 (1995). [2] R. Krivec, M. Ya. Amusia, and V. B. Mandelzweig, Phys. Rev. A 62, 064701 (2000). [3] J. C. Levin et al., Phys. Rev. Lett. 67, 968 (1991); 76, 1220 (1996). [4] S. Kar and Y. K. Ho, Phys. Rev. A, to be published (2008).

  12. Atomic and Molecular Isotope Ratios in Circumstellar Envelopes: Fractionation vs. Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Milam, Stefanie

    The long standing question of "What are the origin, evolution, and fate of our Universe and/or Galaxy?" has puzzled humankind for centuries. One approach to answering this question is to gain further understanding of stellar evolution, since stars are fundamental in galaxy development and evolution. A compilation of stellar composition can reveal the age, dynamics, and possibly the evolutionary state of a galaxy. Stars are the factories of heavy elements, including carbon, nitrogen, and oxygen, that are key to the chemical complexity associated with planetary systems. Primitive materials, such as meteorites and IDPs, have revealed a component of "atypical" isotopic signatures of these fundamental elements denoting a possible stellar origin. Understanding the processes by which these elements derive is essential for astrophysics on cosmochemical, galactic, stellar, and planetary scales. We propose to analyze data obtained from the Herschel Space Observatory of circumstellar envelopes to definitively measure C, N, and O isotope ratios and test current models of photo-selective isotope fractionation vs. nucleosynthetically determined values. This proposal augments completed programs from the Herschel Space Observatory, namely the the HIFISTARS program (PI: Bujarrabal), which at the time of proposal submission a significant portion of data will no longer be under proprietary regulations (https://nhscsci.ipac.caltech.edu/sc/).) The broader implications for this study include fundamental data necessary for furthering our current understanding of stellar nucleosynthesis, circumstellar chemistry, Galactic chemical evolution, and the origin of presolar grains found in primitive materials. We will focus on isotopologues of species formed in thermochemical equilibrium and trace their natal, nucleosynthetic isotope ratios. We will analyze Herschel data obtained for a survey of evolved stars with varying degrees of nuclear processing, evolutionary states, and envelope chemistry

  13. 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

  14. Particle fallout, thermal disequilibrium and volcanic plumes

    NASA Astrophysics Data System (ADS)

    Woods, Andrew W.; Bursik, Marcus I.

    1991-09-01

    We develop a model of a volcanic eruption column that includes the effects of fallout of pyroclasts and thermal disequilibrium. We show that clast fallout, with no thermal disequilibrium, has only a small effect upon the column. However, disequilibrium changes column behaviour significantly, and can even induce collapse. Our results may explain the lower plume heights and less widely dispersed fallout of cone-forming eruptions contrasted with sheet-forming eruptions. The model also predicts that the transition from the gas thrust to the convective region in a column results in an inflection in dispersal curves, that some features of the stratigraphy common to many fall deposits may result from column velocity structure, and that there may exist a region near the volcanic vent in which maximum pyroclast size does not decrease significantly with distance.

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

    NASA Astrophysics Data System (ADS)

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

    The irradiated fusion materials data base will be initially developed in fisson reactors. Hence, predictions of the in-service performance of materials in fusion reactors must account for the effect of a number of variables which differ between fission and fusion environments. Ideally such fission-fusion correlations should reflect sound mechanistic understanding. In this paper we review the effects of the helium to displacement per atom ratio on microstructural evolution, with emphasis on austenitic stainless steels. Charged particle data is analyzed to determine mechanistic trends. These results appear to be consistent with a more detailed comparison made between data from neutron irradiations of type 316 stainless steel in EBR-II (low helium) and HFIR (high helium). Finally, a model calibrated to the fission reactor data is used to extrapolate to fusion conditions.

  16. Nitrogen-to-carbon atomic ratio measured by COSIMA in the particles of comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Fray, Nicolas; Bardyn, Anaïs; Cottin, Hervé; Baklouti, Donia; Briois, Christelle; Engrand, Cécile; Fischer, Henning; Hornung, Klaus; Isnard, Robin; Langevin, Yves; Lehto, Harry; Le Roy, Léna; Mellado, Eva Maria; Merouane, Sihane; Modica, Paola; Orthous-Daunay, François-Régis; Paquette, John; Rynö, Jouni; Schulz, Rita; Silén, Johan; Siljeström, Sandra; Stenzel, Oliver; Thirkell, Laurent; Varmuza, Kurt; Zaprudin, Boris; Kissel, Jochen; Hilchenbach, Martin

    2017-07-01

    The COmetary Secondary Ion Mass Analyzer (COSIMA) on board the Rosetta mission has analysed numerous cometary dust particles collected at very low velocities (a few m s-1) in the environment of comet 67P/Churyumov-Gerasimenko (hereafter 67P). In these particles, carbon and nitrogen are expected mainly to be part of the organic matter. We have measured the nitrogen-to-carbon (N/C) atomic ratio of 27 cometary particles. It ranges from 0.018 to 0.06 with an averaged value of 0.035 ± 0.011. This is compatible with the measurements of the particles of comet 1P/Halley and is in the lower range of the values measured in comet 81P/Wild 2 particles brought back to Earth by the Stardust mission. Moreover, the averaged value found in 67P particles is also similar to the one found in the insoluble organic matter extracted from CM, CI and CR carbonaceous chondrites and to the bulk values measured in most interplanetary dust particles and micrometeorites. The close agreement of the N/C atomic ratio in all these objects indicates that their organic matters share some similarities and could have a similar chemical origin. Furthermore, compared to the abundances of all the detected elements in the particles of 67P and to the elemental solar abundances, the nitrogen is depleted in the particles and the nucleus of 67P as was previously inferred also for comet 1P/Halley. This nitrogen depletion could constrain the formation scenarios of cometary nuclei.

  17. 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.

  18. 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.

  19. Radioactive Fallout From Nuclear Weapons Testing ...

    EPA Pesticide Factsheets

    2017-08-07

    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.

  20. 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…

  1. Monitoring Radiation Fallout Using Locally Available Biotopes

    NASA Astrophysics Data System (ADS)

    Shah, B. R.

    2016-12-01

    Lichens and mosses have long been recognized as ideal indicators of radionuclide contamination released from electronuclear installations or nuclear weapon tests. 137Cs is suitable for monitoring man-made radionuclide fallout because it is soluble in water and readily absorbed by plants. The detection of 137Cs in environmental samples extends supporting the evidence of global impact of radiation fallout from the wepon tests in the past. Various lichen and moss species from diffent biotopes of Kathmandu valley were collected during October 1998 to January 1999 and 20 gm of the representative sample of each species was filled in Merinelli beaker for gamma spectrometry using Multichannel Analyzer (ORTEC-NORLEND, 5600 MCA) coupled with NaI (Tl) detector system. 137Cs activity in most lichen and moss was not different significantly. However, the high concentration of 137Cs was observed in lichens and mosses collected from Doodhpokhari watershed area in Kathmandu valley whereas the highest 137Cs activity around 400 Bq/kg was observed in lichens collected from Ranipauwa, a site outside from the Kathmandu valley. The presence of radionuclide(Cs-137) in samples collected from environment of Kathmandu (Nepal) indicates that there is a fallout of 137Cs in this environment either from neighboring countries through nuclear weapon tests or from nuclear accidents in the past. This talk will further review the monitoring of cesium as a tool to assess the evidence of radiation fallout during the presentation.

  2. Medical examination of Rongelap people six months after exposure to fallout

    SciTech Connect

    Bond, V.P.; Conard, R.A.; Robertson, J.S.

    1955-04-01

    Follow-up medical examinations were made of the Marshallese inhabitants of Rongelap Atoll 6 months after they had been exposed to atomic bomb fallout radiation during the Operation CASTLE test series in March, 1954. During the early acute period following exposure, these people had shown systemic effects and marked hematological changes resulting from penetrating gamma radiation; extensive superficial skin lesions and epilation associated principally with beta and soft gamma radiation from fallout material deposited on uncovered skin areas; and minimal internal contamination with fission products, resulting principally from ingestion of fallout material. At the time of the 6-month resurvey the individuals,more » in general, appeared healthy and normally active, and no deaths had occurred in the interim period. Chest X-rays of all individuals revealed no abnormalities ascribable to the fallout radiation. Analysis of hematological data obtained failed to demonstrate a significant effect of measles on the peripheral blood count. Neutrophile, lymphocyte, and platelet counts were not significantly different from counts taken on the 74th post-exposure day, and none of these values had returned to control levels.« less

  3. 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.

  4. An automatic procedure to forecast tephra fallout

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

    Tephra fallout constitutes a serious threat to communities around active volcanoes. Reliable short-term forecasts represent a valuable aid for scientists and civil authorities to mitigate the effects of fallout on the surrounding areas during an episode of crisis. We present a platform-independent automatic procedure with the aim to daily forecast transport and deposition of volcanic particles. The procedure builds on a series of programs and interfaces that automate the data flow and the execution and subsequent postprocess of fallout models. Firstly, the procedure downloads regional meteorological forecasts for the area and time interval of interest, filters and converts data from its native format, and runs the CALMET diagnostic model to obtain the wind field and other micro-meteorological variables on a finer local-scale 3-D grid defined by the user. Secondly, it assesses the distribution of mass along the eruptive column, commonly by means of the radial averaged buoyant plume equations depending on the prognostic wind field and on the conditions at the vent (granulometry, mass eruption rate, etc). All these data serve as input for the fallout models. The initial version of the procedure includes only two Eulerian models, HAZMAP and FALL3D, the latter available as serial and parallel implementations. However, the procedure is designed to incorporate easily other models in a near future with minor modifications on the model source code. The last step is to postprocess the outcomes of models to obtain maps written in standard file formats. These maps contain plots of relevant quantities such as predicted ground load, expected deposit thickness and, for the case of or 3-D models, concentration on air or flight safety concentration thresholds.

  5. 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 Central

    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. (© 2013 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim) PMID:24376030

  6. 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. © 2015 The Authors. Journal of Biophotonics published by WILEY-VCH Verlag.

  7. Single-atom approximation for Kβ-to-Kα x-ray intensity ratios in chemical compounds of 3d elements

    NASA Astrophysics Data System (ADS)

    Mukoyama, Takeshi; Taniguchi, Kazuo; Adachi, Hirohiko

    2001-04-01

    The single-atom approximation for the Kβ-to-Kα x-ray intensity ratios for chemical compounds of 3d elements has been tested with the discrete-variational Xα (DV-Xα) molecular-orbital (MO) method. The effective numbers of electrons in each atomic shell are obtained with the DV-Xα method and used to calculate the I(Kβ)/I(Kα) ratio in the single-atom approximation. The calculated results are in good agreement with the DV-Xα MO values for octahedral symmetry, but systematically smaller for tetrahedral symmetry. The reason for this discrepancy is ascribed to be the Kβ2,5 component, which is appreciable in some compounds with the tetrahedral symmetry.

  8. Assessment and Control of the Transoceanic Fallout Threat

    DTIC Science & Technology

    1974-08-01

    world- wide inventory of strontium - 90 . At the present time, monthly fallout deposition rates for strontium - 90 are determined for 33 sites in the United...samples at cer- tain of its sites. Although the HASL fallout program has concentrated on strontium - 90 levels, collection schedules and analytic procedures...transoceanic fallout at IR/hr at 1 hour; t 14; t-t = 90 . 0 0 It should be noted that the ingestion of contaminated milk contrib- uted 80% of the thyroid

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

    DTIC Science & Technology

    2012-09-01

    at Dose-Rate Contour Level 0.02 R/ h at H +1 Table 2 presents the measure of effectiveness (MOE) and normalized absolute difference ( NAD ) scores...HYSPLIT Simulation ....................................... 44  Figure 7. WRF Fallout Prediction for Test Shot George, 0.8 R/ h at H +1...47  Figure 8. WRF Fallout Prediction for Test Shot George, 0.2 R/ h at H +1 ....................... 48  Figure 9. WRF Fallout Prediction for

  10. 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.

  11. 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

  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. 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.

  15. Deriving effective atomic numbers from DECT based on a parameterization of the ratio of high and low linear attenuation coefficients.

    PubMed

    Landry, Guillaume; Seco, Joao; Gaudreault, Mathieu; Verhaegen, Frank

    2013-10-07

    Dual energy computed tomography (DECT) can provide simultaneous estimation of relative electron density ρe and effective atomic number Zeff. The ability to obtain these quantities (ρe, Zeff) has been shown to benefit selected radiotherapy applications where tissue characterization is required. The conventional analysis method (spectral method) relies on knowledge of the CT scanner photon spectra which may be difficult to obtain accurately. Furthermore an approximate empirical attenuation correction of the photon spectrum through the patient is necessary. We present an alternative approach based on a parameterization of the measured ratio of low and high kVp linear attenuation coefficients for deriving Zeff which does not require the estimation of the CT scanner spectra. In a first approach, the tissue substitute method (TSM), the Rutherford parameterization of the linear attenuation coefficients was employed to derive a relation between Zeff and the ratio of the linear attenuation coefficients measured at the low and high kVp of the CT scanner. A phantom containing 16 tissue mimicking inserts was scanned with a dual source DECT scanner at 80 and 140 kVp. The data from the 16 inserts phantom was used to obtain model parameters for the relation between Zeff and [Formula: see text]. The accuracy of the method was evaluated with a second phantom containing 4 tissue mimicking inserts. The TSM was compared to a more complex approach, the reference tissue method (RTM), which requires the derivation of stoichiometric fit parameters. These were derived from the 16 inserts phantom scans and used to calculate CT numbers at 80 and 140 kVp for a set of tabulated reference human tissues. Model parameters for the parameterization of [Formula: see text] were estimated for this reference tissue dataset and compared to the results of the TSM. Residuals on Zeff for the reference tissue dataset for both TSM and RTM were compared to those obtained from the spectral method. The

  16. 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.

  17. [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

  18. RESULTS OF COMPUTATIONS MADE FOR DASA-USNRDL FALLOUT SYMPOSIUM

    SciTech Connect

    Read, R.; Wagner, L.; Moorehead, E.

    1962-11-01

    The regression techniques introduced by the Civil Defense Research Project for estimating fallout particle deposition coordinates, their standard ellipses, and isointensity contours have been applied to some of the homework problems assigned for the DASA-USNRDL Fallout Symposium. The results are reported and the estimates are contrasted with estimates based on the assumption that winds are invariant with time. (auth).

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

    PubMed

    Xiao, Xin; Chen, Zaiming; Chen, Baoliang

    2016-03-04

    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. 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.

  2. 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

    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 tomore » 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.« less

  3. Neonatal outcomes following exposure in utero to fallout from Chernobyl.

    PubMed

    Hatch, Maureen; Little, Mark P; Brenner, Alina V; Cahoon, Elizabeth K; Tereshchenko, Valery; Chaikovska, Ludmyla; Pasteur, Igor; Likhtarov, Ilya; Bouville, Andre; Shpak, Victor; Bolshova, Olena; Zamotayeva, Galyna; Grantz, Katherine; Sun, Liping; Mabuchi, Kiyohiko; Albert, Paul; Tronko, Mykola

    2017-12-01

    Iodine 131 (I-131), the principal component of nuclear fallout from the Chernobyl accident, concentrates in the thyroid gland and may pose risks to fetal development. To evaluate this, neonatal outcomes following the accident in April of 1986 were investigated in a cohort of 2582 in utero-exposed individuals from northern Ukraine for whom estimates of fetal thyroid I-131 dose were available. We carried out a retrospective review of cohort members' prenatal, delivery and newborn records. The relationships of dose with neonatal anthropometrics and gestational length were modeled via linear regression with adjustment for potentially confounding variables. We found similar, statistically significant dose-dependent reductions in both head circumference (-1.0 cm/Gy, P = 0.005) and chest circumference (-0.9 cm/Gy, P = 0.023), as well as a similar but non-significant reduction in neonatal length (-0.6 cm/Gy, P = 0.169). Gestational length was significantly increased with increasing fetal dose (0.5 wks/Gy, P = 0.007). There was no significant (P > 0.1) effect of fetal dose on birth weight. The observed associations of radioiodine exposure with decreased head and chest circumference are consistent with those observed in the Japanese in utero-exposed atomic bomb survivors.

  4. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. 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 whichmore » 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.« less

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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

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

    SciTech Connect

    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%. SiO 2 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

  12. xGASS: Total cold gas scaling relations and molecular-to- atomic gas ratios of galaxies in the local Universe

    NASA Astrophysics Data System (ADS)

    Catinella, Barbara; Saintonge, Amélie; Janowiecki, Steven; Cortese, Luca; Davé, Romeel; Lemonias, Jenna J.; Cooper, Andrew P.; Schiminovich, David; Hummels, Cameron B.; Fabello, Silvia; Geréb, Katinka; Kilborn, Virginia; Wang, Jing

    2018-01-01

    We present the extended GALEX Arecibo SDSS Survey (xGASS), a gas fraction-limited census of the atomic hydrogen (HI) gas content of 1179 galaxies selected only by stellar mass (M⋆=109 - 1011.5 M⊙) and redshift (0.01 < z < 0.05). This includes new Arecibo observations of 208 galaxies, for which we release catalogs and HI spectra. In addition to extending the GASS HI scaling relations by one decade in stellar mass, we quantify total (atomic+molecular) cold gas fractions and molecular-to-atomic gas mass ratios, Rmol, for the subset of 477 galaxies observed with the IRAM 30 m telescope. We find that atomic gas fractions keep increasing with decreasing stellar mass, with no sign of a plateau down to log M⋆/M⊙ = 9. Total gas reservoirs remain HI-dominated across our full stellar mass range, hence total gas fraction scaling relations closely resemble atomic ones, but with a scatter that strongly correlates with Rmol, especially at fixed specific star formation rate. On average, Rmol weakly increases with stellar mass and stellar surface density μ⋆, but individual values vary by almost two orders of magnitude at fixed M⋆ or μ⋆. We show that, for galaxies on the star-forming sequence, variations of Rmol are mostly driven by changes of the HI reservoirs, with a clear dependence on μ⋆. Establishing if galaxy mass or structure plays the most important role in regulating the cold gas content of galaxies requires an accurate separation of bulge and disk components for the study of gas scaling relations.

  13. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. 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.

  15. 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.

  16. 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

  17. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Implications of Atmospheric Test Fallout Data for Nuclear Winter.

    NASA Astrophysics Data System (ADS)

    Baker, George Harold, III

    1987-09-01

    Atmospheric test fallout data have been used to determine admissable dust particle size distributions for nuclear winter studies. The research was originally motivated by extreme differences noted in the magnitude and longevity of dust effects predicted by particle size distributions routinely used in fallout predictions versus those used for nuclear winter studies. Three different sets of historical data have been analyzed: (1) Stratospheric burden of Strontium -90 and Tungsten-185, 1954-1967 (92 contributing events); (2) Continental U.S. Strontium-90 fallout through 1958 (75 contributing events); (3) Local Fallout from selected Nevada tests (16 events). The contribution of dust to possible long term climate effects following a nuclear exchange depends strongly on the particle size distribution. The distribution affects both the atmospheric residence time and optical depth. One dimensional models of stratospheric/tropospheric fallout removal were developed and used to identify optimum particle distributions. Results indicate that particle distributions which properly predict bulk stratospheric activity transfer tend to be somewhat smaller than number size distributions used in initial nuclear winter studies. In addition, both ^{90}Sr and ^ {185}W fallout behavior is better predicted by the lognormal distribution function than the prevalent power law hybrid function. It is shown that the power law behavior of particle samples may well be an aberration of gravitational cloud stratification. Results support the possible existence of two independent particle size distributions in clouds generated by surface or near surface bursts. One distribution governs late time stratospheric fallout, the other governs early time fallout. A bimodal lognormal distribution is proposed to describe the cloud particle population. The distribution predicts higher initial sunlight attenuation and lower late time attenuation than the power law hybrid function used in initial nuclear winter

  19. Ingestion of Nevada Test Site fallout: internal dose estimates.

    PubMed

    Whicker, F W; Kirchner, T B; Anspaugh, L R; Ng, Y C

    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 very few cases, infants might have received thyroid doses in excess of 1 Gy, depending on location, diet, and timing of fallout. 131I 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.

  20. 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, andmore » 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.« less

  1. 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

    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 sourcemore » 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.« less

  2. The role of sea ice in the fate of contaminants in the Arctic Ocean: plutonium atom ratios in the Fram Strait.

    PubMed

    Masqué, Pere; Cochran, J Kirk; Hebbeln, Dierk; Hirschberg, David J; Dethleff, Dirk; Winkler, Amelie

    2003-11-01

    Atom ratios of 240Pu to 239Pu in bottom sediments from the Fram Strait are used to provide evidence for the long distance dispersion of Pu in the Arctic Ocean. In particular, low (<0.18) 240Pu/239Pu ratios indicate that plutonium from sources in the Kara Sea and Novaya Zemlya is transported across the basin toward the North Atlantic. The results have implications for the ability of sea ice to incorporate, intercept, and transport contaminants in the Arctic Ocean. They demonstrate that the fates of sea ice and associated contaminants in the Arctic Ocean are closely coupled, with the release of the particulate load and associated chemical species occurring in principal sea ice ablation areas such as the Fram Strait.

  3. 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…

  4. Calibrated sulfur isotope abundance ratios of three IAEA sulfur isotope reference materials and V-CDT with a reassessment of the atomic weight of sulfur

    NASA Astrophysics Data System (ADS)

    Ding, T.; Valkiers, S.; Kipphardt, H.; De Bièvre, P.; Taylor, P. D. P.; Gonfiantini, R.; Krouse, R.

    2001-08-01

    Calibrated values have been obtained for sulfur isotope abundance ratios of sulfur isotope reference materials distributed by the IAEA (Vienna). For the calibration of the measurements, a set of synthetic isotope mixtures were prepared gravimetrically from high purity Ag2S materials enriched in32S, 33S, and 34S. All materials were converted into SF6 gas and subsequently, their sulfur isotope ratios were measured on the SF5+ species using a special gas source mass spectrometer equipped with a molecular flow inlet system (IRMM's Avogadro II amount comparator). Values for the 32S/34S abundance ratios are 22.650 4(20), 22.142 4(20), and 23.393 3(17) for IAEA-S-1, IAEA-S-2, and IAEA-S-3, respectively. The calculated 32S/34S abundance ratio for V-CDT is 22.643 6(20), which is very close to the calibrated ratio obtained by Ding et al. (1999). In this way, the zero point of the VCDT scale is anchored firmly to the international system of units SI. The 32S/33S abundance ratios are 126.942(47), 125.473(55), 129.072(32), and 126.948(47) for IAEA-S-1, IAEA-S-2, IAEA-S-3, and V-CDT, respectively. In this way, the linearity of the V-CDT scale is improved over this range. The values of the sulfur molar mass for IAEA-S-1 and V-CDT were calculated to be 32.063 877(56) and 32.063 911(56), respectively, the values with the smallest combined uncertainty ever reported for the sulfur molar masses (atomic weights).

  5. Fallout from nuclear detonations of February and April 1960.

    PubMed

    KURODA, P K; HODGES, H L; MOORE, H E

    1961-04-14

    A sharp increase in the ratio of strontium-89 to strontium-90 in rain was observed at Fayetteville, Arkansas, after the French nuclear detonations of February and April 1960. Experimental data obtained suggest the possibility that part of the debris from atom bombs detonated in the tropical region may enter the stratosphere.

  6. Improved approach for routine monitoring of129I activity and129I/127I atom ratio in environmental samples using TMAH extraction and ICP-MS/MS.

    PubMed

    Yang, Guosheng; Tazoe, Hirofumi; Yamada, Masatoshi

    2018-05-30

    To reconstruct 131 I deposition and identify the source of radioiodine due to the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, 129 I activity and 129 I/ 127 I atom ratio should be obtained by preparing and analyzing large numbers of samples economically. In this study, great efforts were made to realize mild TMAH (tetramethyl ammonium hydroxide) extraction of environmental samples at 90 °C to obtain solutions suitable for the following triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-QQQ) MS/MS mode analysis. After releasing iodine from organic matter in the TMAH extraction solution via K 2 S 2 O 8 oxidation, organic matter was removed effectively by solvent extraction and back-extraction to avoid a serious matrix effect during ICP-QQQ analysis. At the same time, interfering elements, especially, Mo, Cd, and In were also removed effectively, to avoid their undesirable interferences during mass spectrometric analysis. In addition, 0.01% (NH 4 ) 2 SO 3 was selected to introduce I - into ICP-QQQ to ensure there was no memory effect and a stable signal was gotten. Subsequently, ICP-QQQ MS/MS mode was applied to further eliminate polyatomic interferences ( 127 I(H 2 and D) + , 97 MoO 2 + , 113 InO + , and 113 CdO + ) and isobaric interference from 129 Xe + . Finally, the developed method was successfully applied to measure 129 I/ 127 I atom ratios ((2.61-27.0) × 10 -7 ) and 129 I activities (3.51-11.4 mBq kg -1 ) in soil samples. The developed method allows a greater number of ordinary laboratories to participate in the field of radioiodine analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. 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 aremore » 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

  8. 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…

  9. How to Make the 20-cent Fallout Meter

    SciTech Connect

    Meade, Roger Allen; Rodriguez, Serena R.; Alvarez, Luis

    2017-05-17

    Nobel Prize winner Luis Alvarez published an article on how to build a homemade fallout meter in the November 12, 1961, issue of the Sunday supplement This Week Magazine. A yellowed copy of the article was recently found in the files of the Radiochemistry Group, C-NR, and is reproduced below in its original form.

  10. 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)

  11. 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.

  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. Hydrothermal atomic force microscopy observations of barite step growth rates as a function of the aqueous barium-to-sulfate ratio

    DOE PAGES

    Bracco, Jacquelyn N.; Gooijer, Yiscka; Higgins, Steven R.

    2016-03-19

    The rate of growth of ionic minerals from solutions with varying aqueous cation:anion ratios may result in significant errors in mineralization rates predicted by commonly-used affinity-based rate equations. To assess the potential influence of solute stoichiometry on barite growth, step velocities on the barite (001) surface have been measured at 108 °C using hydrothermal atomic force microscopy (HAFM) at moderate supersaturation and as a function of the aqueous barium:sulfate ratio (r). Barite growth hillocks at r ~ 1 were bounded bymore » $$\\langle$$120$$\\rangle$$ steps, however at r < 1, kink site densities increased, steps followed a direction vicinal to $$\\langle$$120$$\\rangle$$, and the [010] steps developed. At r > 1, steps roughened and rounded as the kink site density increased. Step velocities peaked at r = 1 and decreased roughly symmetrically as a function of r, indicating the attachment rates of barium and sulfate ions are similar under these conditions. We hypothesize that the differences in our observations at high and low r arise from differences in the attachment rate constants for the obtuse and acute $$\\langle$$120$$\\rangle$$ steps. Based on results at low r, the data suggests the attachment rate constant for barium ions is similar for obtuse and acute steps. Based on results at high r, the data suggests the attachment rate constant for sulfate is greater for obtuse steps than acute steps. In conclusion, utilizing a step growth model developed by Stack and Grantham (2010) the experimental step velocities as a function of r were readily fit while attempts to fit the data using a model developed by Zhang and Nancollas (1998) were less successful.« less

  14. Fabrication of high aspect ratio TiO{sub 2} and Al{sub 2}O{sub 3} nanogratings by atomic layer deposition

    SciTech Connect

    Shkondin, Evgeniy, E-mail: eves@fotonik.dtu.dk; Takayama, Osamu; Lavrinenko, Andrei V.

    2016-05-15

    The authors report on the fabrication of TiO{sub 2} and Al{sub 2}O{sub 3} nanostructured gratings with an aspect ratio of up to 50. The gratings were made by a combination of atomic layer deposition (ALD) and dry etch techniques. The workflow included fabrication of a Si template using deep reactive ion etching followed by ALD of TiO{sub 2} or Al{sub 2}O{sub 3}. Then, the template was etched away using SF{sub 6} in an inductively coupled plasma tool, which resulted in the formation of isolated ALD coatings, thereby achieving high aspect ratio grating structures. SF{sub 6} plasma removes silicon selectively withoutmore » any observable influence on TiO{sub 2} or Al{sub 2}O{sub 3}, thus revealing high selectivity throughout the fabrication. Scanning electron microscopy was used to analyze every fabrication step. Due to nonreleased stress in the ALD coatings, the top parts of the gratings were observed to bend inward as the Si template was removed, thus resulting in a gradual change in the pitch value of the structures. The pitch on top of the gratings is 400 nm, and it gradually reduces to 200 nm at the bottom. The form of the bending can be reshaped by Ar{sup +} ion beam etching. The chemical purity of the ALD grown materials was analyzed by x-ray photoelectron spectroscopy. The approach presented opens the possibility to fabricate high quality optical metamaterials and functional nanostructures.« less

  15. Effect of the boundary layer thickness on the hydrodynamic instabilities of coaxial atomization under harmonic flow rate and swirl ratio fluctuations

    NASA Astrophysics Data System (ADS)

    Jorajuria, Corentin; Machicoane, Nathanael; Osuna, Rodrigo; Aliseda, Alberto

    2017-11-01

    Break-up of a liquid jet by a high speed coaxial gas jet is a frequently-used configuration to generate a high quality spray. Despite its extended use in engineering and natural processes, the instabilities that control the liquid droplet size and their spatio-temporal distribution in the spray are not completely understood. We present an experimental measurements of the near field in a canonical coaxial gas-liquid atomizer. The liquid Reynolds number is constant at 103, while the gas jet Reynolds number is varied from 104-106. The liquid injection rate and the swirl ratio are harmonically modulated to understand the effect of unsteadiness on the interfacial instability that triggers primary break-up. The gas velocity is measured using a combination of hot-wire anemometry and 3D PIV, resolving the gas boundary layer and the three-dimensionality of the flow, particularly in the cases with swirl. The development of the hydrodynamic instabilities on the liquid-gas interface is quantified using high speed visualizations at the exit of the nozzle and related to the frequency and growth rates predicted by stability analysis of this boundary layer flow. The resulting droplet size distribution is measured at the end of the break-up process via Particle Phase Doppler Anemometry and compared to stability analysis predictions statistics.

  16. Cancer incidence in an area of radioactive fallout downwind from the Nevada Test Site.

    PubMed

    Johnson, C J

    1984-01-13

    Exposures in southwestern Utah to radioactive fallout (1951 through 1962) from atmospheric nuclear detonations at the Nevada Test Site (NTS) were followed by smaller exposures (1962 through 1979) from venting of underground nuclear detonations. The cancer incidence in a 1951 cohort (4, 125) of Mormon families in southwestern Utah near the NTS was compared with that of all Utah Mormons (1967 through 1975). There were 109 more cases of cancer than expected (288[observed]/179[expected]). Leukemia was most prominent early (1958 through 1966), with 19 cases, five times more than expected (3.6). The excess of leukemia persisted into the later period (1972 through 1980), with 12 cases observed, 3.4 expected. There was an increase in lymphoma. Excess cases of thyroid cancer appeared early and a notable excess appeared later (14/1.7). An excess of breast cancer was noted later (27/14). There were more cancers of the gastrointestinal tract than expected. There was an excess of melanoma (12/4.5), bone cancer (8/0.7), and brain tumors (9/3.9). A subgroup with history of acute fallout effects had a higher cancer incidence. That these cases can be associated with radiation exposures is supported by a comparison between groups of the ratio of cancers of more radiosensitive organs with all other types of cancer.

  17. Plutonium from global fallout recorded in an ice core from the Belukha glacier, Siberian Altai.

    PubMed

    Olivier, Susanne; Bajo, Sixto; Fifield, L Keith; Gäggeler, Heinz W; Papina, Tatyana; Santschi, Peter H; Schotterer, Ulrich; Schwikowski, Margit; Wacker, Lukas

    2004-12-15

    Ice cores from glaciers situated near anthropogenic sources of air pollution provide important archives of the emissions of species with short atmospheric lifetimes. Here we present the history of atmospheric Pu fallout reconstructed from an ice core from the Belukha glacier in the Siberian Altai. Fourteen ice core samples covering the time period 1941-1986 were selected for Pu analysis, chemically processed, and measured using accelerator mass spectrometry. The Pu concentration peaks in 1963, coinciding with the maximum of the nuclear weapons tests and in concordance with the 3H activity concentration peak. The shapes of the 239Pu and 3H profiles reflect two main periods of atmospheric nuclear test activity: premoratorium testing before 1958 and postmoratorium testing in 1961 and 1962. Premoratorium tests contribute about 45% of the integrated Pu inventory. The average 240Pu/239Pu isotopic ratio is 0.18 +/- 0.05, indicating that a large majority of the Pu in the Belukha glacier originates from global stratospheric fallout rather than from direct tropospheric input.

  18. The effect of temperature and H2O/CO2 ratio of the fluid on diamond dissolution morphology from experiments and atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Fedortchouk, Y.

    2012-12-01

    Volatiles are important agents of volcanism while estimates of their content and composition in volcanic rocks have many uncertainties. It is especially challenging for kimberlites, which severe alteration and hybridic nature complicate interpretation of magmatic fluid phase. CO2/H2O ratio of kimberlitic fluid has a notable effect on the emplacement mechanism and geology of kimberlites and on diamond resorption. Dissolution features on diamonds are very sensitive to CO2/H2O ratio in the fluid and our previous work revealed significant and consistent effect of temperature (T) on the shape of trigonal etch pits. In this study we conducted a detailed investigation of morphological changes of trigonal etch pits experimentally developed on diamond crystals at various T in the presence of H2O and CO2-rich fluids aiming to develop a quantitative Atomic-Force Microscopy (AFM)-based method for constraining crystallization conditions and composition of fluid in kimberlite magma using shape and crystallographic measurements of trigonal pits, and to clarify the mechanism of diamond interaction with both fluids. The study uses six diamond crystals after loss of 5-15% of the initial weight in experiments conducted in piston-cylinder apparatus at 1 GPa and T = 1150, 1250, 1350oC in both fluids (H2O and CO2). Diamond faces of each crystal were imaged and their surface features were mapped at 500x magnification using optical microscope. The study focused on the most common dissolution features - trigons, for which we described density, distribution, size, depth / length (D/L) ratio, and grouped them accordingly. Representative trigons from each diamond were further studied on AFM to collect precise crystallographic information for the micro-faces forming their walls, to refine the D/L measurements, and to compare the morphology and regularity of the etch pits, their walls and corners. The focus was placed on quantifying the increase of irregularity and the size of trigonal etch

  19. Radiation Fallout during the Rainy Seasons in the Tropics

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Spjeldvik, Walther; Alves, Mauro; Martin, Inacio

    We have studied the properties of troposphere lightning generated plasmas with instrumentation capable of measuring fluxes and spectra of gamma-rays and neutrons. During 2012 to 2014 observations of the natural gamma-ray background were also carried out in the City of Sao Jose dos Campos, Brazil. The instruments performed near-continuous monitoring with a time resolution of one minute. This permits detailed comparison of the rain properties and gammas time profiles. These observations have revealed that the intensity of gamma-radiation accompanying each rain typically decayed with a time constant of ~ 0.5 hour. It is also the characteristic of decay constant for the Radon descendants and we equate the radiation “fallout” with the 214Pb content in rainfall. A simulation of the radiation “fallout” considering the gamma-ray intensity produced in the decay sequence: 214Pb - 214Bi - 214Po - 210Pb was done. The temporal profile of the 214Pb “fallout” concentration was varied in our simulations until the best-fit of the simulated gamma-ray time profile with the observed gamma-ray profile was obtained. Therefore, the 214Pb concentration in the rainwater has been calculated as a ratio of the reconstructed fallout rate to the rainfall. We found that the 214Pb concentration in rain water varied significantly from one rain to another, and even within a single rain we have detected some two orders of magnitude variation in the 214Pb content with time during the rain. Additionally we have found an apparent anti-correlation between the total rainfall rate and the amount of 214Pb concentration in the rainwater. Indeed, we found a maximum 214Pb concentration in durable drizzling rain, and we noticed that in more intense rainfall events the 214Pb was highest in the beginning of the events. This suggests two different “scavenging” mechanisms whereby possible “below-cloud-wash-out” could account for one time series of 214Pb initiated gamma-rays, and a different

  20. Thermal noise calculation method for precise estimation of the signal-to-noise ratio of ultra-low-field MRI with an atomic magnetometer.

    PubMed

    Yamashita, Tatsuya; Oida, Takenori; Hamada, Shoji; Kobayashi, Tetsuo

    2012-02-01

    In recent years, there has been considerable interest in developing an ultra-low-field magnetic resonance imaging (ULF-MRI) system using an optically pumped atomic magnetometer (OPAM). However, a precise estimation of the signal-to-noise ratio (SNR) of ULF-MRI has not been carried out. Conventionally, to calculate the SNR of an MR image, thermal noise, also called Nyquist noise, has been estimated by considering a resistor that is electrically equivalent to a biological-conductive sample and is connected in series to a pickup coil. However, this method has major limitations in that the receiver has to be a coil and that it cannot be applied directly to a system using OPAM. In this paper, we propose a method to estimate the thermal noise of an MRI system using OPAM. We calculate the thermal noise from the variance of the magnetic sensor output produced by current-dipole moments that simulate thermally fluctuating current sources in a biological sample. We assume that the random magnitude of the current dipole in each volume element of the biological sample is described by the Maxwell-Boltzmann distribution. The sensor output produced by each current-dipole moment is calculated either by an analytical formula or a numerical method based on the boundary element method. We validate the proposed method by comparing our results with those obtained by conventional methods that consider resistors connected in series to a pickup coil using single-layered sphere, multi-layered sphere, and realistic head models. Finally, we apply the proposed method to the ULF-MRI model using OPAM as the receiver with multi-layered sphere and realistic head models and estimate their SNR. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. 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.

  2. The Effectiveness of Soil as Shielding for Expedient Fallout Shelters

    DTIC Science & Technology

    1976-04-01

    FOR EXPEDIENT FALLOUT SHELTERS Final Report April 1976 by Mendel Beer and Martin 0. Cohen for Defense Civil Preparedness Agency Washington, D. C...in the Defense Civil Preparedness Agency and approved for publication. Approval does not signify that the contents necessarily reflect the views and...policies of the Defense Civil Preparedness Agency. MATHEMATICAL APPLICATIONS GROUP, INC. 3 Westchester Plasa Elmsford, New York 10523 ! ’ f SUXMIARY A

  3. A Computer Fallout Model for Operational Type Studies.

    DTIC Science & Technology

    1980-03-01

    34The History of Fallout Prediction," Report: Wright-Patterson AFB, Ohio: Air Force Institute of Technology, 1979. (AD# pending) 3. Davies, C.N...1LA -IAl -WW WW~ flftfttl(U(w 4,ww(wfllm..4f~LQOOQQOOO02fJWW WWWW WU0620WWuWLJ UW W .4~~4~~4~~4..44.4. fifi i f 4 4~..44060060060020020 IAEA 000

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

    DTIC Science & Technology

    1957-10-01

    or after the following Test Series: TRINITY (1945); BUSTER-JANGLE (1951); TUMIBLER- SNAPPER (1952); UPSHOT-KNOTHOLE (1953); and TEAPOT (1955). These...from this type of fallout debris (References 7 and 8). Beginning with the Tumbler- Snapper Series (1952) through the Upshot-Knothole Series (1953) and...addition, the variations in aerosol concentrations deter- mined by several types of air samplers during Operations Tumbler- Snapper (Reference 9), Upshot

  5. 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.

  6. THE DEVELOPMENT OF RADIOACTIVE GLASS SURROGATES FOR FALLOUT DEBRIS

    SciTech Connect

    Martha R. Finck; Leigh R. Martin; Russel R. Lewis

    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); themore » 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.« less

  7. 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.

  8. 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 ofmore » 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.« less

  9. Fallout of pyroclastic debris from submarine volcanic eruptions.

    PubMed

    Cashman, K V; Fiske, R S

    1991-07-19

    Volcanic fallout deposits on land, being widespread and accessible for study, have received much attention and have revealed a great deal about subaerial eruption mechanisms. In contrast, virtually nothing is known about equivalent deposits produced by submarine volcanoes, despite the probable abundance of such material in today's oceans and in accreted volcanic arc terrains. Many submarine deposits may form by the fallout of debris to the sea floor downcurrent from the umbrella region of submarine eruption columns. Experiments on water-saturated pumice and pieces of rock (lithics) show that particles settling to the sea floor at terminal velocities of 10 to 50 centimeters per second will display conspicuous bimodality of particle diameters: pieces of pumice may be five to ten times as large as codeposited lithic fragments. Similar material, erupted into the air and deposited on land, displays less well-developed bimodality; pumice diameters are generally two to three times as large as associated lithics. Submarine fallout deposits are therefore distinctive and may be used to indicate a subaqueous origin for some of the great thicknesses of nonfossiliferous volcanic debris contained in ancient volcanic terrains worldwide whose environment of deposition has been uncertain.

  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. Copyright © 2012 Elsevier Ltd. All rights

  11. 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.

  12. 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

  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. 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.

  15. Optimization of Al2O3/TiO2 nanolaminate thin films prepared with different oxide ratios, for use in organic light-emitting diode encapsulation, via plasma-enhanced atomic layer deposition.

    PubMed

    Kim, Lae Ho; Jeong, Yong Jin; An, Tae Kyu; Park, Seonuk; Jang, Jin Hyuk; Nam, Sooji; Jang, Jaeyoung; Kim, Se Hyun; Park, Chan Eon

    2016-01-14

    Encapsulation is essential for protecting the air-sensitive components of organic light-emitting diodes (OLEDs), such as the active layers and cathode electrodes. Thin film encapsulation approaches based on an oxide layer are suitable for flexible electronics, including OLEDs, because they provide mechanical flexibility, the layers are thin, and they are easy to prepare. This study examined the effects of the oxide ratio on the water permeation barrier properties of Al2O3/TiO2 nanolaminate films prepared by plasma-enhanced atomic layer deposition. We found that the Al2O3/TiO2 nanolaminate film exhibited optimal properties for a 1 : 1 atomic ratio of Al2O3/TiO2 with the lowest water vapor transmission rate of 9.16 × 10(-5) g m(-2) day(-1) at 60 °C and 90% RH. OLED devices that incorporated Al2O3/TiO2 nanolaminate films prepared with a 1 : 1 atomic ratio showed the longest shelf-life, in excess of 2000 hours under 60 °C and 90% RH conditions, without forming dark spots or displaying edge shrinkage.

  16. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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.

  18. SOME RELATIONSHIPS AMONG PARTICLE SIZE, MASS LEVEL AND RADIATION INTENSITY OF FALLOUT FROM A LAND SURFACE NUCLEAR DETONATION,

    DTIC Science & Technology

    The simulation of a realistic fallout environment was required for the design of experiments to evaluate post-nuclear attack reclamation equip ment...MT are presented graphically to facilitate rapid selection of simulated fallout environments .

  19. THE DEVELOPMENT OF VALUES AND BELIEFS IN YOUNG AMERICANS TOWARD FALLOUT SHELTERS AND CIVIL DEFENSE

    DTIC Science & Technology

    What kinds of beliefs and opinions do youngsters in their pre-teen and teenage years have toward fallout shelters and civil defense. 327 eighth and...basis of their degree of favorability towards fallout shelters in general, private shelters, public shelters and civil defense. Each of the attitudes

  20. Impact Analysis of Age on Fallout Fatality Estimations for IND Scenarios

    DTIC Science & Technology

    2017-11-30

    Fallout Fatality Estimations for IND Scenarios DISTRIBUTION A. Approved for public release; distribution is unlimited. November 2017 HDTRA1-14-0003...4 ( 30-11-2017 Technical Report Impact Analysis of Age on Fallout Fatality Estimations for IND Scenarios...other factors. Of these factors, animal data suggests that age has a large impact on radiosensitivity. Historically, casualty estimates have not

  1. 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.

  2. The influence of a fire-induced convection column on radiological fallout patterns

    Treesearch

    A. Broido; A.W. McMasters

    1959-01-01

    Since no nuclear devices have been detonated by the United States under conditions leading to both mass fires and radiological fallout, a theoretical and small-scale experimental study was undertaken to see if fire-induced convection columns could significantly affect fallout patterns. Experiments were conducted in a 6- by 6-foot low-velocity wind tunnel using full-...

  3. Fallout, radiation doses near Dounreay, and childhood leukaemia.

    PubMed Central

    Darby, S C; Doll, R

    1987-01-01

    Possible explanations for the recently reported increased incidence of childhood leukaemia around Dounreay were examined in the light of changes in the national incidence of leukaemia that occurred during the period of exposure to fallout from international testing of nuclear weapons in the atmosphere. It was concluded that the increase could not be accounted for by an underestimate of the risk of leukaemia per unit dose of radiation at low doses and low dose rates, nor by an underestimate of the relative biological efficiency of high as compared with low linear energy transfer radiation. One possible explanation was underestimation of doses to the red bone marrow due to the discharges at Dounreay relative to the dose from fallout, though investigation of ways in which this might have occurred did not suggest anything definite. Other possible explanations included a misconception of the site of origin of childhood leukaemia, outbreaks of an infectious disease, and exposure to some other, unidentified environmental agent. These findings weigh heavily against the hypothesis that the recent increase in childhood leukaemia near Dounreay might be accounted for by radioactive discharges from nuclear plants, unless the doses to the stem cells from which childhood leukaemia originates have been grossly underestimated. PMID:3103820

  4. COMIDA: A radionuclide food chain model for acute fallout deposition

    SciTech Connect

    Abbott, M.L.; Rood, A.S.

    1994-01-01

    A dynamic food chain model and computer code, named {open_quotes}COMIDA,{close_quotes} has been developed to estimate radionuclide concentrations in agricultural food products following an acute fallout event. COMIDA estimates yearly harvest concentrations for five human crop types (Bq kg{sup -1} crop per Bq m{sup -2} deposited) and integrated concentrations for four animal products (Bq d kg{sup -1} animal product per Bq m{sup -2}) for a unit deposition that occurs on any user-specified day of the year. COMIDA is structurally very similar to the PATHWAY model and includes the same seasonal transport processes and discrete events for soil and vegetation compartments. Animalmore » product assimilation is modeled using simpler equilibrium models. Differential transport and ingrowth of up to three radioactive progeny are also evaluated. Benchmark results between COMIDA and PATHWAY for monthly fallout events show very similar seasonal agreement for integrated concentrations in milk and beef. Benchmark results between COMIDA and four international steady-state models show good agreement for deposition events that occur during the middle of the growing season. COMIDA will be implemented in the new Department of Energy version of the MELCOR Accident Consequence Code System for evaluation of accidental releases from nuclear power plants.« less

  5. COMIDA: a radionuclide food chain model for acute fallout deposition.

    PubMed

    Abbott, M L; Rood, A S

    1994-01-01

    A dynamic food chain model and computer code, named "COMIDA," has been developed to estimate radionuclide concentrations in agricultural food products following an acute fallout event. COMIDA estimates yearly harvest concentrations for five human crop types (Bq kg-1 crop per Bq m-2 deposited) and integrated concentrations for four animal products (Bq d kg-1 animal product per Bq m-2) for a unit deposition that occurs on any user-specified day of the year. COMIDA is structurally very similar to the PATHWAY model and includes the same seasonal transport processes and discrete events for soil and vegetation compartments. Animal product assimilation is modeled using simpler equilibrium models. Differential transport and ingrowth of up to three radioactive progeny are also evaluated. Benchmark results between COMIDA and PATHWAY for monthly fallout events show very similar seasonal agreement for integrated concentrations in milk and beef. Benchmark results between COMIDA and four international steady-state models show good agreement for deposition events that occur during the middle of the growing season. COMIDA will be implemented in the new Department of Energy version of the MELCOR Accident Consequence Code System for evaluation of accidental releases from nuclear power plants.

  6. 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 activitymore » 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.« less

  7. Estimating Fallout Building Attributes from Architectural Features and Global Earthquake Model (GEM) Building Descriptions

    SciTech Connect

    Dillon, Michael B.; Kane, Staci R.

    2017-03-01

    A nuclear explosion has the potential to injure or kill tens to hundreds of thousands (or more) of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing fallout radiation exposures) by placing material and distance between fallout particles and individuals indoors. Prior efforts have determined an initial set of building attributes suitable to reasonably assess a given building’s protection against fallout radiation. The current work provides methods to determine the quantitative values for these attributes from (a) common architectural features and data and (b) buildings described using the Global Earthquake Model (GEM) taxonomy. Thesemore » methods will be used to improve estimates of fallout protection for operational US Department of Defense (DoD) and US Department of Energy (DOE) consequence assessment models.« less

  8. Estimating Fallout Building Attributes from Architectural Features and Global Earthquake Model (GEM) Building Descriptions

    SciTech Connect

    Dillon, Michael B.; Kane, Staci R.

    2017-03-01

    A nuclear explosion has the potential to injure or kill tens to hundreds of thousands (or more) of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing fallout radiation exposures) by placing material and distance between fallout particles and individuals indoors. Prior efforts have determined an initial set of building attributes suitable to reasonably assess a given building’s protection against fallout radiation. The current work provides methods to determine the quantitative values for these attributes from (a) common architectural features and data and (b) buildings described using the Global Earthquake Model (GEM) taxonomy. These methods will be used to improve estimates of fallout protection for operational US Department of Defense (DoD) and US Department of Energy (DOE) consequence assessment models.

  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. 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. Themore » 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

  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 ofmore » {+-}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

  12. 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

  13. 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.

  14. 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.

  15. Using fallout plutonium as a probe for erosion assessment.

    PubMed

    Hoo, W T; Fifield, L K; Tims, S G; Fujioka, T; Mueller, N

    2011-10-01

    A study has been carried out to assess the potential of using fallout plutonium (Pu), which originated from atmospheric nuclear-weapons tests, as a tool to investigate recent erosional processes within the lower Cotter water-supply catchment in the Australian Capital Territory. This catchment, which was predominantly pine plantation, was severely affected by a major bush fire in 2003. Accelerator mass spectrometry has been used to measure Pu in soil samples collected from a number of sites across the catchment. The results indicate that less than 1cm of surface soil had been lost since the early 1960s over much of the catchment. Areas of more erodible soil have, however, lost 2-4cm of topsoil, and a loss of ∼6cm of soil was identified at one particular site. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. 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.

  17. 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 resultmore » 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.« less

  18. Soil-to-grain transfer of fallout 90Sr for 28 winter wheat cultivars.

    PubMed

    Gerstmann, U C; Schimmack, W

    2006-09-01

    In order to identify wheat cultivars with minimum soil-to-grain transfer of fallout 90Sr, 28 winter wheat cultivars were investigated at three different sites with different soil types in Upper Bavaria. Each cultivar was grown on an area of 10 m2 and harvested in August 1999. Mean soil-to-grain concentration ratios (C(r)) were 0.151 +/- 0.029, 0.205 +/- 0.035 and 0.060 +/- 0.012, respectively. The C(r) values obtained varied by factors of up to 2.6 for the different cultivars at a given site, and by factors of up to 5.0 for the different sites and a given cultivar. Site-averaged normalized concentration ratios (SANC(r)) ranged from 0.666 +/- 0.062 to 1.503 +/- 0.161. The cultivars Convent, Ludwig, and Semper, showed the lowest uptake of (90)Sr compared to the mean of all cultivars at each site. A cultivar that shows both minimum uptake of 90Sr and 137Cs could not be identified. The results suggest that 90Sr rather than 137Cs might be the limiting radionuclide concerning the use of contaminated land for wheat production. Thus, more efforts might be necessary identifying wheat cultivars with minimum 90Sr uptake.

  19. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. 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 elementmore » 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.« less

  1. 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.

  2. On the dependence of solar flare X-ray spectral line intensity ratios of highly ionized sulfur, calcium, and iron on electron temperature, differential emission measure, and atomic physics

    NASA Technical Reports Server (NTRS)

    Doschek, G. A.; Fludra, A.; Bentley, R. D.; Lang, J.; Phillips, K. J. H.

    1990-01-01

    This paper focuses on what can be learned about the emission measure distribution and certain atomic physics parameters from spectral lines of highly ionized ions of sulfur, calcium, and iron that appear in solar flare spectra. The particular lines chosen for analysis allow the electron temperature to be determined independently of the assumption of ionization equilibrium. An attempt is made to find emission measure models based on selected functional dependences of emission measure on temperature that reproduce the observed temperatures deduced from spectral line ratios as well as the relative intensities of resonance lines of different elements.

  3. 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.

    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 andmore » soluble Cs isotopes or 137Cs contained in plants from soil uptake.« less

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

    DOE PAGES

    Holliday, K. S.; Dierken, J. M.; Monroe, M. L.; ...

    2017-01-11

    Our 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. We interrogated a sample set of 48 individual fallout specimens in order 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. Our result suggests thatmore » 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.« less

  5. Tephra Fallout Hazard Assessment for VEI5 Plinian Eruption at Kuju Volcano, Japan, Using TEPHRA2

    NASA Astrophysics Data System (ADS)

    Tsuji, Tomohiro; Ikeda, Michiharu; Kishimoto, Hiroshi; Fujita, Koji; Nishizaka, Naoki; Onishi, Kozo

    2017-06-01

    Tephra fallout has a potential impact on engineered structures and systems at nuclear power plants. We provide the first report estimating potential accumulations of tephra fallout as big as VEI5 eruption from Kuju Volcano and calculated hazard curves at the Ikata Power Plant, using the TEPHRA2 computer program. We reconstructed the eruptive parameters of Kj-P1 tephra fallout deposit based on geological survey and literature review. A series of parameter studies were carried out to determine the best values of empirical parameters, such as diffusion coefficient and the fall time threshold. Based on such a reconstruction, we represent probabilistic analyses which assess the variation in meteorological condition, using wind profiles extracted from a 22 year long wind dataset. The obtained hazard curves and probability maps of tephra fallout associated to a Plinian eruption were used to discuss the exceeding probability at the site and the implications of such a severe eruption scenario.

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

    SciTech Connect

    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.

    2017-01-11

    Our 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. We interrogated a sample set of 48 individual fallout specimens in order 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. Our 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.

  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 mediummore » 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.« less

  8. 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.

  9. 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

  10. 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.

  11. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    SciTech Connect

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

    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. Twomore » 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.« less

  13. 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.

  14. 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.

  15. 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.

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

    SciTech Connect

    Grinstein, Fernando F; Wachtor, Adam J; Nelson, Matt

    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 airflowmore » 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.« less

  17. Dust fallout in Kuwait city: deposition and characterization.

    PubMed

    Al-Awadhi, Jasem M; Alshuaibi, Arafat A

    2013-09-01

    Dust fallouts in Kuwait city was monitored on monthly basis during the period from March 2011 to February 2012 at 10 locations. The results of this study reveal that: (1) monthly dust deposition rates ranged from 0.002 to 0.32 kg/m(2) with average deposition rate of 0.053 kg/m(2) and annual average deposition rate of 0.59 kg/m(2), ranking the first out of 56 dust deposition rates observed throughout the world; (2) on average, about 55.9% of the settled dust have fine to very fine sand fraction sizes, while silt and clay comprise an average of 37.4 and 1.4% of the total sample, respectively; (3) the concentrations for Zn and Mo out of 15 other elements analyzed from the dust were up to 11 times higher than their soil background values in Kuwait, while Pb and Ni were about seven times higher; (4) Mo, Ni, Pb and Zn show maximum enrichment relative to the upper continental crustal component (Mn); (5) Sr, Zr and Zn show highest concretions among all collected samples; and (6) quartz and calcite were the dominant minerals in the dust samples. The distribution of the heavy metals in dust seems to be controlled mainly by the land uses and the volume of traffic emissions. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. 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

  19. Effects of gas to melt ratio on the microstructure of an Al–10.83Zn–3.39Mg–1.22Cu alloy produced by spray atomization and deposition

    SciTech Connect

    Guo, S.; Ning, Z.L.; Zhang, M.X.; Cao, F.Y.; Sun, J.F.

    2014-01-15

    Various gas to melt ratios (GMR) that govern the cooling rate of spray forming can be achieved through controlling the atomizer form and the atomization pressure. The effect of the GMR on microstructures of an Al–10.83Zn–3.39Mg–1.22Cu alloy produced through spray forming has been studied using electron microscopy. When the GMR is high at 3.5, dendritic structure and quasi-crystalline i-Mg{sub 32}(AlZn){sub 49} particles inherited from the original powders can be observed. Spray forming at medium GMR of 2.3 produces equiaxed α-Al grains and MgZn{sub 2} phase that discontinuously distributes along the grain boundaries and within the grains as small particles. The low GMR of 1.4 corresponds to low cooling rate. Coarse and equiaxed α-Al grains together with eutectic structure consisting of b.c.c.-Mg{sub 32}(AlZn){sub 49} and α-Al phases along the grain boundaries are obtained. - Highlights: • At high GMR, the broken fragments and i-Mg{sub 32}(AlZn){sub 49} quasicrystal are observed. • At medium GMR, microstructure consists of α-Al equiaxed grains and MgZn{sub 2} phase. • At low GMR, the coarsened α-Al grains and bcc-Mg{sub 32}(AlZn){sub 49} eutectic appear.

  20. Estimates of exposure rates and fallout arrival times near the Nevada Test Site.

    PubMed

    Thompson, C B

    1990-11-01

    One of the tasks of the Off-Site Radiation Exposure Review Project (ORERP) was to estimate doses to individuals resulting from exposure to fallout from nuclear testing at the Nevada Test Site (NTS). Dose estimates are based on estimates of the exposure rate 12 h post-detonation (H + 12) and the time of fallout arrival from events producing discernible fallout at locations off the NTS. These estimates are derived from both published fallout patterns and survey meter readings taken by monitors in the field. Each fallout pattern is digitized, and kriging is used to interpolate estimates of exposure rate and arrival time onto a 10-km grid covering the contours of the pattern. These grid values are then used to calculate estimates at any location of interest within the pattern. Exposure rate is also estimated from the survey meter readings for a particular nuclear event by decay-correcting the measurements near a selected location to H + 12 and then aggregating them into one estimate. Estimates of discernible exposure rate and time of fallout arrival from 74 nuclear events at the NTS are contained in the Town Data Base. Estimates are given for 352 locations in Arizona, California, Nevada, and Utah. Each record in the data base contains estimates for a specified event and location. The distribution of exposure rate is represented by a geometric mean and standard deviation; the distribution of fallout arrival time is represented by an arithmetic mean and standard deviation. A more extensive description and a listing of the Town Data Base are included in a separate report.

  1. 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.

  2. Short-term soil mixing quantified with fallout radionuclides

    NASA Astrophysics Data System (ADS)

    Kaste, James M.; Heimsath, Arjun M.; Bostick, Benjamin C.

    2007-03-01

    Soil mixing plays a significant role in contaminant transport, carbon sequestration, and landscape evolution, yet the rates and driving mechanisms are poorly constrained. Here we use depth profiles and advection-diffusion modeling of fallout nuclides to quantify differences in short-term (<100 yr) physical soil mixing across contrasting landscapes. We constrain advection in soils using the distribution of cosmogenic 7Be and weapons-derived isotopes, and quantify mixing with a steady-state model of vertical 210Pb transport. On a forested landscape in the Bega Valley in southeastern Australia and on grasslands in Marin County, California, where bioturbation is documented as the dominant sediment transport mechanism, we calculate diffusion-like mixing coefficients of 1 2 cm2 yr-1. In montane forest soils of northern New England, we observe little field evidence of short-term mixing, and find that the traditional advection-diffusion model fails to describe 210Pb profiles. Because nuclide profiles here can be described with a simple model of litterfall, organic matter decay, and radioactive decay, we argue that diffusion-like processes are barely active on short time scales, and that the advection-diffusion model overestimates diffusion-like transport. While animal bioturbation and soil freezing cycles have little effect on the fate of elements in New England, physical soil mixing drives transport at Bega Valley and Marin County. We suggest that the absence of soil stirring that we quantify in New England forests may explain the slow physical erosion here (˜0.2 cm/k.y.) relative to the actively bioturbated soils of Bega Valley and Marin County (5 10 cm/k.y.).

  3. 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

  4. Review of reduction factors by buildings for gamma radiation from radiocaesium deposited on the ground due to fallout.

    PubMed

    Yoshida-Ohuchi, Hiroko; Matsuda, Norihiro; Saito, Kimiaki

    2018-02-26

    In order to estimate residents' external dose due to radionuclide exposure resulting from fallout deposit on the ground, the shielding and dose reduction effects provided by structures such as houses and workplaces are taken into account as most individuals spend a large portion of their time indoors. Many works on both calculation and measurement for European and American settlements have been reported and factors such as, shielding factors, protection factors, reduction factors, and location factors have been determined. However, measurement data for Japanese settlements are lacking. Thus, the Japanese government used reduction factors given in the International Atomic Energy Agency documents from American and European settlements when Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident occurred. The United Nations Scientific Committee on the Effects of Atomic Radiation used location factors from European settlements for the same reason. Soon after the FDNPP accident, several measurements and calculations were performed to obtain specific reduction factors for Japanese settlements due to this lack of data. This research reviews previous studies that determined factors such as, shielding factors, protection factors, reduction factors, and location factors and summarizes specific results for Japan. We discuss the issues in determining these factors and in applying them to estimate indoor dose. The contribution of surface contamination to the indoor ambient dose equivalent rate is also discussed. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. 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.

  6. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. 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.

  8. 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

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

    USGS Publications Warehouse

    Robbins, J.A.; Holmes, C.; Halley, R.; Bothner, Michael H.; 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.

  10. Sources of fine-grained sediment to streams using fallout radionuclides in the Midwestern United States

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Fluvial sediment is a major factor in aquatic habitat degradation. Understanding the sources of this sediment is a necessary component of management plans and policies aimed at reducing sediment inputs. Because of the time intensive framework of most sediment-source studies, spatial interpretations are often limited to the study watershed. To address sediment sources on a larger scale, the U.S. Geological Survey- National Water Quality Assessment (NAWQA) Program as part of the Midwest Stream Quality Assessment, used fallout radioisotopes (excess lead-210, cesium-137, and beryllium-7) to determine the source ((upland (surface runoff) or channel derived)) of fine-grained (<0.063 mm) bed sediment in the Cornbelt Ecoregion. The study area encompassed parts of 11 states in the Midwestern United States covering 648,239 km2 of the United States. Sampling occurred in July and August of 2013, in conjunction with water chemistry, aquatic-habitat and ecological community assessments. Ninety-nine watersheds were sampled, the majority of which were predominately agricultural, with contributing areas ranging between 6.7 to 5,893 km2. Using the ratio of beryllium-7 to excess lead-210, the percent of upland to channel-derived sediment was estimated. Results indicate that sediment sources vary among the 99 watersheds. Channel sediment is an important source presumably from bank erosion. Upland sediment was not the dominant source of sediment in many of these agricultural watersheds. Suspended-sediment samples collected over an 8-week period for 3 watersheds also show that the percent of upland versus channel sediment varies spatially and temporally.

  11. 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.

  12. 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.

  13. 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.

  14. Enhanced tortuosity for electrolytes in microwave irradiated self-organized carbon-doped Ni/Co hydroxide nanocomposite electrodes with higher Ni/Co atomic ratio and rate capability for an asymmetric supercapacitor

    NASA Astrophysics Data System (ADS)

    Kumar, Niraj; Kumar, Viresh; Panda, H. S.

    2017-11-01

    We demonstrate a green, facile and rapid microwave-mediated process for fabricating carbon black (CB) incorporated Ni/Co hydroxide porous nanocomposites and study the effect of various mass loading of CB on supercapacitor performance. The structure and interactions between CB and Ni/Co hydroxide are characterized by using x-ray diffraction, Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy, which suggest the miniaturization of the single-phase Ni/Co hydroxide formation time. A morphology study reveals that the addition of CB into Ni/Co hydroxide develops a loose network structure with well-defined architectural pores. In addition, the nanocomposites demonstrate noticeable improvements in porosity and atomic ratio of Ni/Co with an increasing percentage of carbon, which results in a higher diffusion of electrolytes, and hence electrical conduction. The developed electrode materials exhibit a maximum specific capacitance value of 1526 Fg-1 at current density 1 Ag-1 with excellent cyclic stability (92% retention at 5000 cycles), energy density (76 Wh Kg-1), power density (250 W Kg-1) and rate capability. A solid state asymmetric supercapacitor device is fabricated and utilized to brighten a commercial LED effectively for validating real usage.

  15. 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

  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. Evaluation of Spalling Fallout on Excavation Disturbed Zone under Deep Hard Rock Tunnel

    NASA Astrophysics Data System (ADS)

    Azit, Romziah; Ashraf Mohamaed Ismail, Mohd; You Jiang, Thang

    2017-08-01

    The prediction of compressive stress-induced failures is of concern when designing and constructing facilities in rock for deep underground excavation. The purpose of this study is to model compressive stress-induced failure and fallouts with appropriate material models and strength parameters for deep hard rock tunnel excavation. Three method of numerical modelling are used, which are Generalised Hoek-Brown; Mohr-Coulomb; and Mohr-Coulomb with Cohesion Softening Friction Hardening (CSFH) material models for capturing the observed rock behaviour. A parametric study was also carried out to verify that the peak friction angle of 10° used in CSFH model. The results show that numerical models used only Generalised Hoek-Brown and Mohr Coulomb strength parameters does not show a good agreement with the observed fallout. The comparison revealed that the numerical models using the Mohr-Coulomb with CSFH provides most realistic to the observation fallout length. This model is valid for prediction of failure and fallouts in hard rock masses with high quality (GSI >65 MPa; intact rock compressive strength >70MPa).

  18. Perspective on the local fallout model used in the SCOPE/ENUWAR study

    SciTech Connect

    Harvey, T.F.

    1988-03-01

    The graphical local fallout model used in the SCOPE/ENUWAR study, and its progenitor, KDFOC2, are compared to several fallout models. These include the numerical models SEER3, WSEG10, and DELFIC, as well as the analytical fallout model found in Glasstone and Dolan's ''The Effects of Nuclear Weapons - 1977''. DELFIC is considered by many to be the standard that other fallout models should be calibrated against. Visual, graphical, and tabular comparisons of the results of various models are made for a hypothetical 1-Mt, fission, nuclear explosion. Some results are compared down to 0.1 Gy/hr. We find that KDFOC2 and the scopemore » model patterns compare extremely well with DELFIC patterns below 30 Gy/hr. However, WSEG10 and SEER3 compare less well. The Glasstone and Dolan model is in even poorer agreement, in that it substantially overpredicts both the downwind distances and area coverages for all dose-rate isopleths when compared to DELFIC. At low yields, KDFOC2, SEER3 and DELFIC predictions have been compared to Nevada Test Site measurements. When these results are reviewed, KDFCO2 is shown to be the superior model, with DELFIC second, and SEER3 a distant third. 13 refs., 7figs., 3 tabs.« less

  19. 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.

    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 withinmore » 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.« less

  20. 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.

  1. 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

  2. Mn$sup 54$ CONCENTRATION FROM FALL-OUT IN RELATION TO THE AGE AND ORGANS OF UNIO MANCUS ELONGATULUS (MOLLUSCA, LAMELLIBRANCHIA)(in Italian)

    SciTech Connect

    Gaglione, P.; Ravera, O.

    1962-01-01

    Mn/sup 54/ is an activation product of the shell of the atomic bombs. This radionuclide in fallout and in biological material collected in Northern Italy was not ordinarily found. The Unionidae represent an exception, because in these organisms a certain amount of radiomanganese (Mn-54) was measured. The results from the spectrometric analysis carried out on Unio mancus var. elongatulus, Pfeiffer, collected near Angera (Lago Maggiore), show clearly a very strong correlation between the Mn/sup 54/ concentration and the age of the Mollusc. In addition, the Mn/sup 54/ content in the different parts of the body of Unio is very different.more » (auth)« less

  3. "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.…

  4. 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.

  5. 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

  6. 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.

  7. Diffusive mass transport in agglomerated glassy fallout from a near-surface nuclear test

    DOE PAGES

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

    2017-12-15

    Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here in this paper, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K tomore » 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/ 30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ~2200 K is inferred (1σ uncertainty of ~200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.« less

  8. Diffusive mass transport in agglomerated 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.

    2018-02-01

    Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K to 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ∼2200 K is inferred (1σ uncertainty of ∼200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.

  9. 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.

  10. Diffusive mass transport in agglomerated 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.

    2017-12-15

    Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here in this paper, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K to 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ~2200 K is inferred (1σ uncertainty of ~200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.

  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. 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. 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.

  14. 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.

  15. 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.

  16. Ratios of internal conversion coefficients

    SciTech Connect

    Raman, S.; Ertugrul, M.; Nestor, C.W. . E-mail: CNestorjr@aol.com; Trzhaskovskaya, M.B.

    2006-03-15

    We present here a database of available experimental ratios of internal conversion coefficients for different atomic subshells measured with an accuracy of 10% or better for a number of elements in the range 26 {<=} Z {<=} 100. The experimental set involves 414 ratios for pure and 1096 ratios for mixed-multipolarity nuclear transitions in the transition energy range from 2 to 2300 keV. We give relevant theoretical ratios calculated in the framework of the Dirac-Fock method with and without regard for the hole in the atomic subshell after conversion. For comparison, the ratios obtained within the relativistic Hartree-Fock-Slater approximation are also presented. In cases where several ratios were measured for the same transition in a given isotope in which two multipolarities were involved, we present the mixing ratio {delta} {sup 2} obtained by a least squares fit.

  17. Leukemia in Utah and radioactive fallout from the Nevada test site. A case-control study.

    PubMed

    Stevens, W; Thomas, D C; Lyon, J L; Till, J E; Kerber, R A; Simon, S L; Lloyd, R D; Elghany, N A; Preston-Martin, S

    1990-08-01

    Previous studies reported an association between leukemia rates and amounts of fallout in southwestern Utah from nuclear tests (1952 to 1958), but individual radiation exposures were unavailable. Therefore, a case-control study with 1177 individuals who died of leukemia and 5330 other deaths (controls) was conducted using estimates of dose to bone marrow computed from fallout deposition rates and subjects' residence locations. A weak association between bone marrow dose and all types of leukemia, all ages, and all time periods after exposure was found. This overall trend was not statistically significant, but significant trends in excess risk were found in subgroups defined by cell type, age, and time after exposure. The greatest excess risk was found in those individuals in the high-dose group with acute leukemia who were younger than 20 years at exposure and who died before 1964. These results are consistent with previous studies and with risk estimates for other populations exposed to radiation.

  18. Characteristic of microplastics in the atmospheric fallout from Dongguan city, China: preliminary research and first evidence.

    PubMed

    Cai, Liqi; Wang, Jundong; Peng, Jinping; Tan, Zhi; Zhan, Zhiwei; Tan, Xiangling; Chen, Qiuqiang

    2017-11-01

    Microplastic pollution has exhibited a global distribution, including seas, lakes, rivers, and terrestrial environment in recent years. However, little attention was paid on the atmospheric environment, though the fact that plastic debris can escape as wind-blown debris was previously reported. Thus, characteristics of microplastics in the atmospheric fallout from Dongguan city were preliminarily studied. Microplastics of three different polymers, i.e., PE, PP, and PS, were identified. Diverse shapes of microplastics including fiber, foam, fragment, and film were found, and fiber was the dominant shape of the microplastics. SEM images illustrated that adhering particles, grooves, pits, fractures, and flakes were the common patterns of degradation. The concentrations of non-fibrous microplastics and fibers ranged from 175 to 313 particles/m 2 /day in the atmospheric fallout. Thus, dust emission and deposition between atmosphere, land surface, and aquatic environment were associated with the transportation of microplastics.

  19. 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.

  20. 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.

  1. Comments on Strontium-90 in Surface Air in Relation to Stratospheric Fallout.

    NASA Astrophysics Data System (ADS)

    Rangarajan, C.; Eapen, C. D.

    1984-08-01

    The time variation of the spring peak of stratospheric fallout is examined with surface air data of Cs-137 concentrations from about 30 stations in the zone 9 to 75°N and 80°W to 115°E. This study is likely to be more realistic than one derived from data confined to a particular meridian, such as the United States 80th meridian fallout sampling network. It is seen from an examination of the data that the spring peak of stratospheric fallout is progressively delayed with increasing latitude from 9 to 50°N. At latitudes beyond 50°N, no clear trend can be postulated due to limited data. The reason for this progressive delay in the appearance of the spring peak is likely to be due to changes in the circulation pattern, rather than variations in precipitation scavenging, as regions with different distributions of rainfall have the same progressive delay in the spring peak.

  2. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Scoria Fallout Modeling and the 3 March 2015 VEI-2 Eruption of Villarica Volcano, Chile

    NASA Astrophysics Data System (ADS)

    Anderson, J.; Johnson, J. B.; Bowman, D. C.; Ronan, T.; Brand, B. D.

    2015-12-01

    In March 2015, Villarrica volcano erupted a spectacular 1.5 km lava fountain and 6-8 km plume, depositing a thin (several mm or cm) layer of scoria tens of km toward the east and southeast. We show results of numeric models (the advection-diffusion equation solver Tephra2, and particle-tracking models) informed by NOMADS atmospheric data used to model this fallout. Models show strong winds (up to 25 m/s) toward the east and southeast concentrating the narrow deposit in those directions, and the vertical variation of wind direction predicts particle sorting along the wind-transverse direction. Both of these were observed in the field. We discuss the challenges faced by fallout models of scoria: because of its irregular shapes, high and variable porosity, and propensity to break apart on impact, aerodynamic properties are difficult to assess by physical observations. This introduces ambiguity when comparing models to observations. Finally, we demonstrate how short-term hazard predictions can benefit from the integration of fallout models with weather forecasts up to several days in advance, and how hazard communication to the public can benefit from snapshots and animations showing zones subject to tephra fall and time delays from eruption to impact.

  4. 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

  5. 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

  6. Protracted exposure to fallout: the Rongelap and Utirik experience.

    PubMed

    Lessard, E T; Miltenberger, R P; Cohn, S H; Musolino, S V; Conard, R A

    1984-03-01

    From June 1946 to August 1958, the U.S. Department of Defense and the U.S. Atomic Energy Commission (AEC) conducted nuclear weapons tests in the Northern Marshall Islands. On 1 March 1954, BRAVO, an above-ground test in the Castle series, produced high levels of radioactive material, some of which subsequently fell on Rongelap and Utirik Atolls due to an unexpected wind shift. On 3 March 1954, the inhabitants of these atolls were moved out of the affected area. They later returned to Utirik in June 1954 and to Rongelap in June 1957. Comprehensive environmental and personnel radiological monitoring programs were initiated in the mid 1950s by Brookhaven National Laboratory to ensure that body burdens of the exposed Marshallese subjects remained within AEC guidelines. Their body-burden histories and calculated activity ingestion rate patterns post-return are presented along with estimates of internal committed effective dose equivalents. External exposure data are also included. In addition, relationships between body burden or urine-activity concentration and declining continuous intake were developed. The implications of these studies are: (1) the dietary intake of 137Cs was a major component contributing to the committed effective dose equivalent for the years after the initial contamination of the atolls; (2) for persons whose diet included fish, 65Zn was a major component of committed effective dose equivalent during the first years post-return; (3) a decline in the daily activity ingestion rate greater than that resulting from radioactive decay of the source was estimated for 137Cs, 65Zn, 90Sr and 60Co; (4) the relative impact of each nuclide on the estimate of committed effective dose equivalent was dependent upon the time interval between initial contamination and rehabilitation; and (5) the internal committed effective dose equivalent exceeded the external dose equivalent by a factor of 1.1 at Utirik and 1.5 at Rongelap during the rehabitation period. Few

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Fallout track from the accident at the fourth block of the Chernobyl NPP in certain regions of the Leningrad, Novgorod, and Bryansk districts. I.

    SciTech Connect

    Krivokhatskii, A.S.; Rogozin, Y.M.; Smirnova, E.A.

    1994-11-01

    Results are presented from reconnaissance by automobile and foot of the western regions of the Leningrad district, the northwestern regions of the Novgorod district, and the Novozykovsk region of the Bryansk district. Sites of soil contaminated by radionuclides are determined. The main contaminants of the studied regions are{sup 137}Cs and {sup 134}Cs. The activity ratio between these enables the contamination to be assigned a Chernobyl origin. Data are presented for the {sup 137}Cs distribution among the soil fractions. The thinnest fraction that is the most active of the studied samples (Novye Bobovichi village, Bryansk district) contains condensed and fuel fallout components. The vertical migration of {sup 137}Cs in the various soil types is studied. The principal amount of {sup 137}Cs (up to 80-90%) in the fall of 1992 in virgin parts was concentrated in the upper soil layers (0-6 cm).

  12. Derivation of Effective Resuspension Factors in Scenarios for Inhalation Exposure Involving Resuspension of Previously Deposited Fallout by Nuclear Detonations at Nevada Test Site

    DTIC Science & Technology

    2009-11-30

    greater distances suggests that the closest measurement location was some distance from the centerline of the fallout plume . However, the...distance. These data give information on variations in particle-size distributions at different distances from the centerline of a fallout plume . Only...of smaller particles in fallout should be larger near the edges of a plume , where the total activity would be relatively low, than near the center of

  13. 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

  14. A screening study of thyroid cancer and other thyroid diseases among individuals exposed in utero to iodine-131 from Chernobyl fallout.

    PubMed

    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

    2009-03-01

    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. 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). 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. 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.

  15. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Additional calculations of radionuclide production following nuclear explosions and Pu isotopic ratios for Nevada Test Site events.

    PubMed

    Hicks, H G

    1990-11-01

    A method is reviewed for calculating dry ground deposition of any radionuclide in off-site fallout from a nuclear explosion. Calculations are in agreement with measurements. A list of all calculations to date is presented, along with how to obtain copies. In addition, a table of ratios of 240Pu:239Pu and 241Pu:239Pu for NTS explosions is included.

  17. 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.

  18. Atom Tunneling in Chemistry.

    PubMed

    Meisner, Jan; Kästner, Johannes

    2016-04-25

    Quantum mechanical tunneling of atoms is increasingly found to play an important role in many chemical transformations. Experimentally, atom tunneling can be indirectly detected by temperature-independent rate constants at low temperature or by enhanced kinetic isotope effects. In contrast, the influence of tunneling on the reaction rates can be monitored directly through computational investigations. The tunnel effect, for example, changes reaction paths and branching ratios, enables chemical reactions in an astrochemical environment that would be impossible by thermal transition, and influences biochemical processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 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)

  20. 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)

  1. 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.

  2. 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.

  3. Detection of fallout 241Am in U.S. Atlantic salt marsh soils

    NASA Astrophysics Data System (ADS)

    Boyd, B. M.; Sommerfield, C. K.

    2017-09-01

    We report the presence of the fallout radionuclide 241Am (t1/2 = 433 years) in salt marsh soils from two U.S. Atlantic estuaries and discuss its utility as a particle tracer and geochronometer. This work is motivated by the knowledge that 137Cs, the most widely used geochronometer in environmental studies, will decay to extinction during the next century. At the same time, levels of 241Am, produced by radioactive decay of fallout 241Pu, will continue to increase on Earth's surface as they have since the height of atmospheric nuclear weapons testing in the 1960s. Measurements of 241Am in soils at eighteen salt marsh locations were made by non-destructive gamma spectrometry and compared to activities of 137Cs in the same samples. Results indicate that decay of fallout 241Pu can explain the presence of 241Am in the soils, and that the activities are sufficiently high to provide meaningful chronological information with acceptable confidence limits. We achieved a detection limit of 0.28-1.47 Bq kg-1 using low-energy, planar germanium detectors and 11-55 g powderized samples. Activities of 241Am (0.08-6.44 Bq kg-1) were similar in mineral- and organic-rich marsh soils indicating that soil composition does not appear to influence the initial capture of 241Pu and retention of its 241Am progeny. Given its high affinity for fine particles, long half-life, and ease of measurement by non-destructive gamma spectrometry, 241Am has potential to serve as an alternative to 137Cs geochronometry in salt marshes and perhaps other estuarine and coastal environments.

  4. 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.

  5. 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

  6. Twenty-year review of medical findings in a Marshallese population accidentally exposed to radioactive fallout

    SciTech Connect

    Conard, R.A.

    1975-01-01

    A summary is presented of results of medical examinations of inhabitants of the Marshall Islands during the 20-year period following the exposure of Rongelap people to radioactive fallout in 1954. The initial effect observed was $beta$ burns of the skin of some individuals. Few significant findings were observed during the subsequent 9-year period, although an increase in miscarriages and stillbirths among the exposed women was noted. In 1963 some thyroid abnormalities and growth retardation of some children were noted. (177 references). (CH)

  7. Study on particle size distributions of the fallout dust from the atmosphere of Qena, Egypt

    NASA Astrophysics Data System (ADS)

    El Shazly, Sayed M.

    The total number of particles, particle size and shape, as well as particle size distribution have been studied for the fallout dust in the atmosphere of Qena (upper Egypt). Dust particles were collected directly on slides for microscopic analysis at two collection sites. The frequency distribution of sizes is plotted against equal intervals of size. The results shwo that the highest percentage of particles have size < 5 μm and are of irregular shape. The high degree of similarly between the PSD results indicates a small variability in atmospheric conditions in Qena during the period of study. The effective mean particle diameters were calculated.

  8. Nuclear Reactor Accident Fallout Artifacts: Unusual Black Spots on Digital Radiographs.

    PubMed

    Kashimura, Yasuhiro; Chida, Koichi

    2015-12-01

    The Fukushima nuclear power plant accident resulted in the discharge of radioactive particulate material into the atmosphere. Consequently, several hospitals in Japan have observed black spots on x-ray computed radiography (CR) images caused by particulate radioactive fallout. These black spots have no effect on human health. To reduce the influence of black spots on CR images, we need to erase latent images on imaging plates (IPs) immediately before clinical use and read the IPs soon after the x-ray examination. Alternatively, the contaminated felt of a cassette can be cleaned or exchanged, if possible.

  9. Constraining Erosion Timescales and Magnitudes with Multiple Fallout Radionuclide Tracers in Owens Valley, CA

    NASA Astrophysics Data System (ADS)

    Kaste, J. M.; Evans, G.; Elmore, A. J.; Vest, K. R.; Okin, G. S.

    2011-12-01

    In central Owens Valley, California, groundwater withdrawals during periods of drought have been linked to reduced vegetation cover and a shift from grass-dominated to shrub-dominated landscapes over the past few decades. While there is field evidence of significant soil deflation in areas where native grass cover has declined, the timing and magnitude of wind erosion in this part of the valley is not well understood. An understanding of the spatiotemporal relationship between groundwater pumping, vegetation change, and erosion is necessary for effective water and land use management in this ecologically sensitive area. Here we use measurements of fallout radionuclides 7Be, 137Cs, and 210Pb in soils and dust to quantify the timing and extent of soil deflation in areas of Owens Valley where climate, land use history, and ecological changes are well constrained. We measure cosmogenic 7Be in soils to constrain the heterogeneity of wet deposition and to scale reference inventories for radioactive fallout across an arid precipitation gradient in the valley. Using a mass balance advection-diffusion-decay model, we show that in arid environments, soil 137Cs inventories are sensitive to erosion magnitude, but not so much the timing of the erosion, because vertical advection rates are slow and fallout halted in the 1960s. In contrast, soil 210Pb inventories are sensitive to both the timing and the magnitude of erosion because of near-constant meteoric inputs that can replenish the soil in years following a deflation event. Using a coupled model, we can constrain both the timing and magnitude of soil erosion in Owens Valley over the past half century, and assess how water management and abrupt climate fluctuations can lead to soil loss. Our model indicates a higher likelihood of erosion in central Owens Valley in the past three decades, particularly during and following the drought period of 1986-1992. However, we observed significant spatial variability in total erosion

  10. 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). Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. 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

  12. 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.

  13. Atom Interferometry

    ScienceCinema

    Kasevich, Mark

    2017-12-22

    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?

  14. 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…

  15. Fallout from Nuclear Cratering Shot DANNY BOY. I. Radiochemical Analysis and Some Physical Observations on Selected Samples

    DTIC Science & Technology

    1980-02-01

    UNANNOUNCED -- 1 USNRDL-TR-67- 90 (EX) EXTRACTED VERSION FALLOUT FROM NUCLEAR • CRATERING SHOT DANNY BOY I. Radiochemical Analysis and Some .* Physical...PERFOCRMING4 ORGANIZATION NAME AND0 ADDRESS 90 . PPROGRAA CLtMLNT.PROJtCT TASK U.S. Naval Radiological Defense Laboratory AE UKUI UBR San Francisco...0, Id-nlitr by bl.1h n.-,b.11 Danny Boy Fallout Radiochemnistry Debris Particles 20. A l! mACT (C-11-,.~ ..Id. Of ý.tW 6,d Id. nISj fy L

  16. Fallout plutonium and natural radionuclides in annual bands of the coral Montastrea annularis, St. Croix, U.S. Virgin Islands

    NASA Astrophysics Data System (ADS)

    Benninger, Larry K.; Dodge, Richard E.

    1986-12-01

    We have investigated the banded coral Montastrea annularis as a recorder of the history of fallout Pu in surface seawater. Thirty annual growth bands, representing growth during 'coral years' 1951-1980, were subsampled from M. annularis collected at St. Croix, U.S. Virgin Islands. 'Coral years' begin and end in late summer-early autumn and are designated for the calendar year in which they end. 239,240Pu was finite in coral years 1954-1980, and the coral Pu record is very simply related to the fallout history of 90Sr. Peaks in coral Pu in coral years 1959 and 1964 correspond to fallout peaks in 1959 and 1963, respectively. Peak broadening and time lags in the coral Pu record, as compared to the 90Sr fallout record are consistent with retention of fallout Pu in surface seawater for about two years (characteristic removal time) during the period of major fallout, and possibly longer thereafter. The simplicity of the coral Pu record and its close correspondence with fallout history suggest that 239,240Pu was incorporated into the coral skeleton with constant discrimination relative to Ca; the effects of speciation and oxidation state upon Pu incorporation are presently unknown. To aid the Pu interpretation Ca, Mg, Sr, Na and natural radionuclides (238U, 228Ra, 232Th and 210Pb) 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 238U and 228Ra 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. 232Th was not detected with certainty; this implies that terrigenous particles were not consistently entrapped within the coral skeleton. Interpretation of 210Pb was difficult because 226Ra was not measured. Montastrea annularis preserves a record of fallout Pu. To make this record useful it must be considered in the

  17. [Economic hardship and fallout on households of the management of hydrocephalus in Benin].

    PubMed

    Gandaho, Hugues Jean-Thierry; Hounton, Sennen Houesse; Kelani, Amina; Darga, Christian; Hoinsou-Hans, Isaac; Agbani, Florence; Lalya, Francis; Koumakpayi, Sikiratou; Ayivi, Blaise

    2017-04-27

    Objectives: The socioeconomic profile of households and families of children attending hospital for hydrocephalus were documented and analysed. Main costs related to diagnosis and care were reviewed. The emotional fallout and social well-being of families were also analysed. Methods: This retrospective cross-sectional study (January 2006 to January 2015) was based on costs borne by households and families for neurosurgical care of children with hydrocephalus. Results: Sixty children (1 day to 12 years old) had been hospitalized for hydrocephalus in Cotonou-Benin. In 19 cases, the families were single-parent families. In 44 cases, the parents were self-employed workers or private company employees. Public servants, eligible for national health system assistance, accounted for a mere 16 cases. Twenty six children did not receive any financial support, whereas the total average care-related out-of-pocket expenditure for families during the hospital stay was approximately €1,777 (1,117,500 FCFA), i.e. almost 14 times the average monthly income reported by the parents (82,600 FCFA – approximately €120). After hospitalization, 31 mothers had lost their jobs and 21 couples experienced marital issues and their plans to have children. Twelve recent separations were recorded, as well as one indirect maternal death related to depression. Conclusion: In Benin Republic, surgical care for paediatric hydrocephalus represents catastrophic out-of-pocket expenditures for households and families and other living expenses. Families experience significant emotional fallout with effects on couple relationships and survival.

  18. Radiation doses in Sweden resulting from the Chernobyl fallout: a review.

    PubMed

    Holmberg, M; Edvarson, K; Finck, R

    1988-08-01

    The risk associated with the Chernobyl fallout is the product of radiation dose and risk factor per dose unit. The radiation doses originate from inhalation of radioactive particles, ground irradiation from deposited nuclides and internal irradiation caused by contaminated food. In Sweden the largest dose contribution is due to external radiation. The deposition has been mapped by aerial measurements and in situ high-resolution gamma measurements at ground level over the whole country. On the basis of these measurements, population-weighted doses for external radiation have been estimated. Whole-body measurements on randomly selected individuals have been performed in order to estimate the average dose from internal irradiation. The collective dose, i.e. the sum of all individual doses, has been estimated to be about 1500 man-Sievert for the first year after Chernobyl and 5000-7000 man-Sievert for a 50-year period. Using a risk factor of 0.02 fatal cancers per man-Sievert the Chernobyl fallout over Sweden might cause 100-200 fatal cancers.

  19. 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.

  20. 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)

  1. Fallout from the Chernobyl accident and overall cancer incidence in Finland.

    PubMed

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

    2013-10-01

    We studied whether incidence of all cancer sites combined was associated with the radiation exposure due to fallout from the Chernobyl accident in Finland. An emphasis was on the first decade after the accident to assess the suggested "promotion effect". The segment of Finnish population with a stable residence in the first post-Chernobyl year (2 million people) was studied. The analyses were based on a 250m × 250m grid squares covering all of Finland and all cancer cases except cancers of the breast, prostate and lung. Cancer incidence in four exposure areas (based on first-year dose due to external exposure <0.1 mSv, 0.1-1.3, 0.3-0.5, or ≥ 0.5 mSv) was compared before the Chernobyl accident (1981-1985) and after it (1988-2007) taking into account cancer incidence trends for a longer period prior to the accident (since 1966). There were no systematic differences in the cancer incidence in relation to radiation exposure in any calendar period, or any subgroup by sex or age at accident. The current large and comprehensive cohort analysis of the relatively low levels of the Chernobyl fallout in Finland did not observe a cancer promotion effect. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. 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.

    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 caremore » 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)« less

  3. Poisson Ratios of Polycrystals

    NASA Astrophysics Data System (ADS)

    Milstein, Frederick; Budek, Andrew M.

    1987-08-01

    Poisson ratios of fee and bcc polycrystals are calculated for a variety of atomic models and the theoretical results are compared with experiment. In contrast with previously reported results, it is found that an accurate description of polycrystalline Poisson ratios of metals is obtained from the model in which the binding energy Ebind consists of a structure dependent part Estr and a volume dependent part Evol. Investigations are made of the general, inherent abilities of various subsets of this model to describe experimental polycrystalline Poisson ratios; these subsets include the Cauchy model (i.e. Evol is neglected in Ebind) and the Milstein-Rasky model (i.e. the volume dependent contribution to the bulk modulus χvol is neglected). In addition, specific com putations of polycrystalline Poisson ratios are made for the complete families of bcc and fcc Morse function (Cauchy) crystals and for (non-Cauchy) models (simplified forms of which are suggested by pseudopotential theory for the noble metals).

  4. 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.

  5. Optical pumping of a lithium atomic beam for atom interferometry

    NASA Astrophysics Data System (ADS)

    Gillot, Jonathan; Gauguet, Alexandre; Büchner, Matthias; Vigué, Jacques

    2013-12-01

    We apply optical pumping to prepare the lithium beam of our atom interferometer in a single hyperfine-Zeeman sublevel: we use two components of the D1-line for pumping the 7Li atoms in a dark state F, m F = +2 (or -2) sublevel. The optical pumping efficiency has been characterized by two techniques: state-selective laser atom deflection or magnetic dephasing of the atom interferometer signals. The first technique has not achieved a high sensitivity, because of a limited signal to noise ratio, but magnetic dephasing signals have shown that about 95% of the population has been transferred in the aimed sublevel, with similar results for three mean velocities of the atomic beam covering the range 744-1520 m/s.

  6. 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.)

  7. 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)

  8. 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.)

  9. 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)

  10. 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.)

  11. The nature of rockfall as the basis for a new fallout area design criteria for 0.25:1 slopes.

    DOT National Transportation Integrated Search

    1994-09-01

    The data gathered from rolling nearly 2800 rocks off several 0.25H:1V slopes into three differently shaped ditches (flat, 6H:1V and 4H:1V) was used to develop 12 design charts for rock fallout areas. The data were analyzed using simple statistical an...

  12. 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.

  13. 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.

  14. Meteorological modeling of arrival and deposition of fallout at intermediate distances downwind of the Nevada Test Site.

    PubMed

    Cederwall, R T; Peterson, K R

    1990-11-01

    A three-dimensional atmospheric transport and diffusion model is used to calculate the arrival and deposition of fallout from 13 selected nuclear tests at the Nevada Test Site (NTS) in the 1950s. Results are used to extend NTS fallout patterns to intermediate downwind distances (300 to 1200 km). The radioactive cloud is represented in the model by a population of Lagrangian marker particles, with concentrations calculated on an Eulerian grid. Use of marker particles, with fall velocities dependent on particle size, provides a realistic simulation of fallout as the debris cloud travels downwind. The three-dimensional wind field is derived from observed data, adjusted for mass consistency. Terrain is represented in the grid, which extends up to 1200 km downwind of NTS and has 32-km horizontal resolution and 1-km vertical resolution. Ground deposition is calculated by a deposition-velocity approach. Source terms and relationships between deposition and exposure rate are based on work by Hicks. Uncertainty in particle size and vertical distributions within the debris cloud (and stem) allow for some model "tuning" to better match measured ground-deposition values. Particle trajectories representing different sizes and starting heights above ground zero are used to guide source specification. An hourly time history of the modeled fallout pattern as the debris cloud moves downwind provides estimates of fallout arrival times. Results for event HARRY illustrate the methodology. The composite deposition pattern for all 13 tests is characterized by two lobes extending out to the north-northeast and east-northeast, respectively, at intermediate distances from NTS. Arrival estimates, along with modeled deposition values, augment measured deposition data in the development of data bases at the county level; these data bases are used for estimating radiation exposure at intermediate distances downwind of NTS. Results from a study of event TRINITY are also presented.

  15. 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. Estimatesmore » 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.« less

  16. 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.

  17. 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

  18. [Cesium-137 and strontium-90 from nuclear weapon fallout using tobacco as an example].

    PubMed

    Fischer, E; Schmidt, J A; Kalus, W H; Schelenz, R

    1983-01-01

    42 to 75 pCi cesium-137 and 702 to 903 pCi strontium-90 per kg were found in samples of tobacco of German origin and from commercial cigarette. The presence of these radionuclides in tobacco is attributed to the fallout from nuclear explosions. Taking into consideration mean transfer rates of the radionuclides in the main stream smoke condensate and average consumption of cigarettes, whole body radiation doses for inhalation have been calculated to be in the range 10(-3) to 10(-4) mrem/year and per person. This means, they are in the same order of magnitude as radiation doses by inhalation of ambient air. They are smaller by a factor of 10(-4) than the radiation exposure due to ingestion of these radionuclides from the total diet.

  19. 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.

    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 ofmore » 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.« less

  20. Understanding Polycyclic Aromatic Hydrocarbon transfers at the catchment scale combining chemical and fallout radionuclide analyses

    NASA Astrophysics Data System (ADS)

    Gateuille, D.; Evrard, O.; Lefevre, I.; Moreau-Guigon, E.; Alliot, F.; Chevreuil, M.; Mouchel, J.-M.

    2012-04-01

    Reducing environmental contamination constitutes a major challenge for industrialized countries. Furthermore, in the European Union, Water Framework Directive (WFD; Directive 2000/60/EC) requires that the member state water bodies reach good ecological and chemical status by 2015. Polycyclic Aromatic Hydrocarbons (PAHs) are a group of persistent organic pollutants considered as priority pollutants because of their mutagenic and carcinogenic properties. They are mostly emitted by human activities such as household heating or road traffic. Although emissions have decreased during the last decades, a large amount of PAHs have been released into the atmosphere for the last two centuries. In recent years, studies dealing with PAHs have grown in number but most of them were restricted to the measurement of PAHs concentrations in the different compartments of the environment (air, soil, sediment, water, etc.). In this context, there remains a lack of knowledge about the transfers and, consequently, about the persistence of these compounds in the environment. This question is particularly acute in the Seine River basin where very high concentrations in PAHs are reported in sediment, thereby compromising the achievement of the good chemical status required by WFD. Our study aims to quantify PAHs transfers at the catchment scale by combining chemical analysis with gamma spectrometry. Atmospheric fallout, soil, river water and sediment samples were collected in two upstream sub-catchments of the Seine River basin during one year. Chemical analyses, restricted to 15 of the 16 PAHs selected by the US Environmental Protection Agency (USEPA), were carried out to determine PAHs concentrations in all samples. Contamination spectra were used to outline the potential origin of pollution. 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. material that

  1. 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.

  2. 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

  3. Measurement of fallout {sup 239}Pu levels in urine samples by fission track analysis

    SciTech Connect

    Moorthy, A.R.; Doty, R.M.

    1996-11-01

    A Fission Track Analysis (FTA) method for assessing 239Pu in urine samples was first developed at Brookhaven National Laboratory (BNL) in 1988; it then had a detection limit of 100 aCi (3.7 {micro}Bq). Since that time, several steps were introduced that increased chemical recovery and lowered the detection limit to less than 1O aCi per sample. These improvements include a process of micro-column separation of plutonium in the final stages. The improved FTA method was applied to 22 urine samples from male staff at BNL. The results showed that 239Pu from fallout excreted in urine was 33 +/- 11 aCi (1.2 {micro}Bq) per day.

  4. 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.

  5. Mass Transport of Condensed Species in Aerodynamic Fallout Glass from a Near-Surface Nuclear Test

    NASA Astrophysics Data System (ADS)

    Weisz, David Gabriel

    In a near-surface nuclear explosion, vaporized device materials are incorporated into molten soil and other carrier materials, forming glassy fallout upon quenching. Mechanisms by which device materials mix with carrier materials 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. A surface deposition layer was observed preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused. Eleven such boundaries were studied using spatially resolved analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nano-scale secondary ion mass spectrometry (NanoSIMS), we identified higher concentrations of uranium from the device in 7 of the interface layers, as well as isotopic enrichment (>75% 235U) in 9 of the interface layers. Major element analysis of the interfaces revealed the deposition layer to be chemically enriched in Fe-, Ca- and Na-bearing species and depleted in Ti- and Al-bearing species. The concentration profiles of the enriched species at the interface are characteristic of diffusion. Three of the uranium concentration profiles were fit with a modified Gaussian function, representative of 1-D diffusion from a planar source, to determine time and temperature parameters of mass transport. By using a historical model of fireball temperature to simulate the cooling rate at the interface, the temperature of deposition was estimated to be 2200 K, with 1? uncertainties in excess of 140 K. The presence of Na-species in the layers at this estimated temperature of deposition is indicative of an oxygen rich fireball. The notable depletion of Al-species, a refractory oxide that is highly abundant in the soil, together with the enrichment of Ca-, Fe-, and 235U-species, suggests an anthropogenic source of

  6. 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. Copyright © 2013. Published by Elsevier Ltd.

  7. 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.

  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. 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.

  10. Postglacial eruptive history of Laguna del Maule volcanic field in Chile, from fallout stratigraphy in Argentina

    NASA Astrophysics Data System (ADS)

    Fierstein, J.; Sruoga, P.; Amigo, A.; Elissondo, M.; Rosas, M.

    2012-12-01

    The Laguna del Maule (LdM) volcanic field, which surrounds the 54-km2 lake of that name, covers ~500 km2 of rugged glaciated terrain with Quaternary lavas and tuffs that extend for 40 km westward from the Argentine frontier and 30 km N-S from the Rio Campanario to Laguna Fea in the Southern Volcanic Zone of Chile. Geologic mapping (Hildreth et al., 2010) shows that at least 130 separate vents are part of the LdM field, from which >350 km3 of products have erupted since 1.5 Ma. These include a ring of 36 postglacial rhyolite and rhyodacite coulees and domes that erupted from 24 separate vents and encircle the lake, suggesting a continued large magma reservoir. Because the units are young, glassy, and do not overlap, only a few ages had been determined and the sequence of most of the postglacial eruptions had not previously been established. However, most of these postglacial silicic eruptions were accompanied by explosive eruptions of pumice and ash. Recent investigations downwind in Argentina are combining stratigraphy, grain-size analysis, chemistry, and radiocarbon dating to correlate the tephra with eruptive units mapped in Chile, assess fallout distribution, and establish a time-stratigraphic framework for the postglacial eruptions at Laguna del Maule. Two austral summer field seasons with a tri-country collaboration among the geological surveys of the U.S., Chile, and Argentina, have now established that a wide area east of the volcanic field was blanketed by at least 3 large explosive eruptions from LdM sources, and by at least 3 more modest, but still significant, eruptions. In addition, an ignimbrite from the LdM Barrancas vent complex on the border in the SE corner of the lake traveled at least 15 km from source and now makes up a pyroclastic mesa that is at least 40 m thick. This ignimbrite (72-75% SiO2) preceded a series of fall deposits that are correlated with eruption of several lava flows that built the Barrancas complex. Recent 14C dates suggest

  11. 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

  12. Atom chips on direct bonded copper substrates

    SciTech Connect

    Squires, Matthew B.; Stickney, James A.; Carlson, Evan J.; Baker, Paul M.; Buchwald, Walter R.; Wentzell, Sandra; Miller, Steven M.

    2011-02-15

    We present the use of direct bonded copper (DBC) for the straightforward fabrication of high power atom chips. Atom chips using DBC have several benefits: excellent copper/substrate adhesion, high purity, thick (>100 {mu}m) copper layers, high substrate thermal conductivity, high aspect ratio wires, the potential for rapid (<8 h) fabrication, and three-dimensional atom chip structures. Two mask options for DBC atom chip fabrication are presented, as well as two methods for etching wire patterns into the copper layer. A test chip, able to support 100 A of current for 2 s without failing, is used to determine the thermal impedance of the DBC. An assembly using two DBC atom chips is used to magnetically trap laser cooled {sup 87}Rb atoms. The wire aspect ratio that optimizes the magnetic field gradient as a function of power dissipation is determined to be 0.84:1 (height:width).

  13. 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 exposuresmore » 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

  14. 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.

  15. 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.

  16. Overview of the National Cancer Institute's activities related to exposure of the public to fallout from the Nevada Test Site.

    PubMed

    Wachholz, B W

    1990-11-01

    The Department of Health and Human Services (DHHS) was directed by Congress to assess the risk of thyroid cancer from 131I associated with fallout from the atmospheric testing of nuclear weapons at the Nevada Test Site. The National Cancer Institute (NCI) was requested by DHHS to address Public Law 97-414, Section 7 (a), which directs DHHS to "(1) conduct scientific research and prepare analyses necessary to develop valid and credible assessments of the risks of thyroid cancer that are associated with thyroid doses of Iodine 131; (2)...develop...methods to estimate the thyroid doses of Iodine 131 that are received by individuals from nuclear bomb fallout; (and) (3)...develop...assessments of the exposure to Iodine 131 that the American people received from the Nevada atmospheric nuclear bomb tests." In addition, the University of Utah, under contract with the NCI, is carrying out a study to determine if the incidence of thyroid disease and leukemia among identified populations in Utah may be related to exposure from fallout originating at the Nevada Test Site.

  17. 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

  18. MEDICAL SURVEY OF RONGELAP PEOPLE SEVEN YEARS AFTER EXPOSURE TO FALLOUT

    SciTech Connect

    Conard, R. A.; MacDonald, H. E.; Meyer, L. M.

    1962-05-01

    Results of a medical survey of the people of Rongelap in the Marshall lslands, carried out in March 1961, 7 years after the accident, are presented. A total of 267 people was examined, most of them on Rongelap Island and some at Kwajalein and Majuro Atolls. Physical examinations showed no acute illnesses present nor any diseases which could be directly associated with radiation effects. However, lt was noted that several of the older people, particularly in the exposed group, were becoming quite feeble and helpless. Residual skin changes in areas previously showing lesions from fall-out were present with certainty inmore » about 10 people. Dental examinations revealed no differences between the exposed and unexposed group. Examinations for the detection of such late effects of radiation as cancer and leukemia revealed no evidence of malignancies in any of the people, exposed or unexposed. Results of growth and development in children and hematological studies are also given. (P.C.H.)« less

  19. Near-field radioactive particle dynamics and empirical fallout patterns in Chernobyl's Western and Northern Plumes

    NASA Astrophysics Data System (ADS)

    Chesser, Ronald K.; Rodgers, Brenda E.

    We compared geographically referenced ground-based measurements of gamma and beta radiation to model predictions of particle dispersion and estimate the influences of particle sizes, wind speeds, and vertical and lateral turbulence on the near-field (<12 km) fallout patterns resulting from Chernobyl's first two releases of radioactive materials. Excellent conformity between empirical measures and model predictions was found when reasonable atmospheric parameters were assigned. Whereas particle size contributions to the two plumes were similar, atmospheric influences on particle flow differed markedly, resulting in rapid widening, meander, and diminished radiation doses in the Northern Plume relative to that for the narrower and intensely radioactive Western Plume. The Northern Plume is probably the result of multiple particle characteristics released simultaneously. Near-field depositions were due to particulate nuclear fuel probably ejected during helicopter drops of sand onto the burning reactor. Depositions much farther north of the reactor complex were likely due to smaller (1-3 μm) aerosols of volatile radionuclides. Predominant particle sizes in the near-field traces of both plumes were >40 μm in diameter. These large particulates eliminate passive dispersion of oxidized nuclear fuel and aerosol releases of volatile elements as the primary sources of contamination in the Northern Plume at distances <12 km from the Chernobyl reactor.

  20. Improving Eruption Source Parameter characterization for tephra fallout hazard scenarios at Campi Flegrei caldera (Italy)

    NASA Astrophysics Data System (ADS)

    Mele, Daniela; Isaia, Roberto; Sulpizio, Roberto; Macedonio, Giovanni; Costa, Antonio; Fabio, Dioguardi

    2017-04-01

    Tephra fallout associated with renewal of volcanism at the Campi Flegrei caldera is a serious threat to the Neapolitan area. Previous studies reconstructed probability maps of fall deposits of three different eruption scenarios, representative of past activity: a high-magnitude event similar to the ˜4.5 ka Agnano-Monte Spina eruption, a medium-magnitude event, similar to the ˜4.1 ka Astroni 6 eruption, and a low-magnitude event similar to the ˜4.2 ka Averno2 eruption. A semi-analytical model (HAZMAP) was used to estimate the Eruption Source Parameters (ESP), such as total erupted mass, eruption column height, and Total Grain-Size Distributions (TGSD) associated to these eruptions. ESP were obtained by best-fitting field data of proximal and medial outcrops. However, sensitivity studies of the dispersion of fall deposit showed that TGSD, fine-ash mass and particle aggregation processes are the main cause of the uncertainty. Here we integrate the previous works using new field data including samples of medial-distal outcrops to better reconstruct the TGSD of the reference eruptions. Moreover 3D particle shape parameters obtained by microtomographic technics is used to better characterize drag law and hence particle settling velocity. The new data set is used to feed tephra dispersal models in order to produce a series of maps of tephra loading on the ground for the most representative eruptive scenarios accounting for different meteorological data and the eruptive parameters.

  1. 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.

  2. "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…

  3. 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

  4. 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,…

  5. 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

  6. 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. Published by Elsevier Ltd.

  7. 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.

  8. 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

  9. Potential impacts of tephra fallout from a large-scale explosive eruption at Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Biass, S.; Todde, A.; Cioni, R.; Pistolesi, M.; Geshi, N.; Bonadonna, C.

    2017-10-01

    We present an exposure analysis of infrastructure and lifeline to tephra fallout for a future large-scale explosive eruption of Sakurajima volcano. An eruption scenario is identified based on the field characterization of the last subplinian eruption at Sakurajima and a review of reports of the eruptions that occurred in the past six centuries. A scenario-based probabilistic hazard assessment is performed using the Tephra2 model, considering various eruption durations to reflect complex eruptive sequences of all considered reference eruptions. A quantitative exposure analysis of infrastructures and lifelines is presented primarily using open-access data. The post-event impact assessment of Magill et al. (Earth Planets Space 65:677-698, 2013) after the 2011 VEI 2 eruption of Shinmoedake is used to discuss the vulnerability and the resilience of infrastructures during a future large eruption of Sakurajima. Results indicate a main eastward dispersal, with longer eruption durations increasing the probability of tephra accumulation in proximal areas and reducing it in distal areas. The exposure analysis reveals that 2300 km of road network, 18 km2 of urban area, and 306 km2 of agricultural land have a 50% probability of being affected by an accumulation of tephra of 1 kg/m2. A simple qualitative exposure analysis suggests that the municipalities of Kagoshima, Kanoya, and Tarumizu are the most likely to suffer impacts. Finally, the 2011 VEI 2 eruption of Shinmoedake demonstrated that the already implemented mitigation strategies have increased resilience and improved recovery of affected infrastructures. Nevertheless, the extent to which these mitigation actions will perform during the VEI 4 eruption presented here is unclear and our hazard assessment points to possible damages on the Sakurajima peninsula and the neighboring municipality of Tarumizu.

  10. 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.

  11. 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.

  12. Cesium Isotope Ratios as Indicators of Nuclear Power Plant Operations

    SciTech Connect

    Darin Snyder; James Delmore; Troy Tranter

    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 themore » 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.« less

  13. 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

  14. Ultracold-Atom Accelerometers

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    1995-01-01

    Proposed class of accelerometers and related motion sensors based on use of ultracold atoms as inertial components of motion transducers. Ultracold atoms supplant spring-and-mass components of older accelerometers. As used here, "ultracold atoms" means atoms with kinetic energies equivalent to temperatures equal to or less than 20 mK. Acclerometers essentially frictionless. Primary advantage high sensitivity.

  15. 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

    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).

  16. Estimate of thyroid doses for David A. Timothy and June Carrell from Nevada Test Site local fallout

    SciTech Connect

    Anspaugh, L.R.; Ng, Y.C.

    1985-10-28

    David A. Timothy and June Rogers Carrell are litigants in Timothy vs US. They allege that their thyroid cancers have resulted from harm from radiation doses received as a result of local fallout from the testing of nuclear weapons at the Nevada Test Site. We have calculated a best estimate of the thyroid dose received by each litigant from external exposure and the ingestion of radionuclides with food. For David Timothy, the dose estimate is 7.8 rads. For June Carrell, it is 2.6 rads. 22 refs., 3 tabs.

  17. 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.

  18. Fallout strontium-90 and cesium-137 in northern Alaskan ecosystems during 1959--1970

    SciTech Connect

    Hanson, Wayne C.

    1973-05-01

    Cycling routes, rates of transport, and resultant concentrations of the fallout radionuclides 90Sr and 137Cs in northern Alaskan ecosystems were defined during the period 1959 to 1970. Radiochemical analysis of extensive samples of biota and whole-body counting of 137Cs in Eskimo and Indian ethnic groups were related to ecological principles, especially the concept of trophic niche, which elucidated the observed patterns of radionuclide concentrations. Experiments involving Sr and Cs radioisotopes applied to natural Cladonia-- Cetraria lichen carpets yielded effective half-times of 1.O to 1.6 years for Sr and more than 10 years for Cs. Direct and indirect estimates of 131Csmore » half-times in Eskimos on a caribou meat diet were made by dietary manipulation and by relating dietary 137Cs intake and resultant change between periodic whole body counts. Effective half- times of 70 days for adults (more than 21 years old) and minors (14 to 20 years old) and of 45 days for children (less than 14 years old) were found. Suitable mathematical models were used to compute lichen forage ingestion rates of free- ranging adult caribou (4.5 to 5.0 kg dry weight per day), caribou meat ingestion rates of Anaktuvuk Pass residents (up to 2 kg wet weight per day for men), and 90Sr body burdens of Anaktuvuk Pass residents during the period 1952 to 1968 (maximum value of 8 nCi in adult males during late 1966 to early 1967). Special emphasis was made of cultural influences upon the food-gathering patterns of the native peoples studied. Culture change, especially in the form of food stamps, welfare payments, acquisition of snowmobiles, and improved housing was documented throughout the study and noticeably reduced the radionuclide accumulations. Total radiation dose rates to the Anaktuvuk Pass adult population were estimated to be about 100 mrad/year from natural sources, 60 to 140 mrad/year from 137Cs body burdens, and 20 to 130 mrad/year from 90Sr body burdens.« less

  19. Sediment dynamics during the rainy season in tropical highland catchments of central Mexico using fallout radionuclides

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Némery, Julien; Gratiot, Nicolas; Duvert, Clément; Ayrault, Sophie; Lefèvre, Irène; Poulenard, Jérôme; Prat, Christian; Bonté, Philippe; Esteves, Michel

    2010-12-01

    Tropical regions are affected by intense soil erosion associated with deforestation, overgrazing, and cropping intensification. This land degradation leads to important on-site (e.g., decrease in soil fertility) and off-site (e.g., reservoir siltation and water pollution) impacts. This study determined the mean soil particle and sediment residence times in soils and rivers of three subcatchments (3-12 km 2) with contrasted land uses (i.e., cropland, forests, and rangelands) draining to a reservoir located in highlands of the transvolcanic Mexican belt. Calculations were based on rainfall amount and river discharges as well as on fallout radionuclide measurements (Be-7, Cs-137, and Pb-210) conducted on rainfall precipitated samples, soil sampled in the catchments, and suspended sediment collected by automatic samplers in the river during most storms recorded throughout the 2009 rainy season. Calculations using a radionuclide two-box balance model showed that the mean residence time of particles in soils ranged between 5000 ± 1500 and 23,300 ± 7000 years. In contrast, sediment residence time in rivers was much shorter, fluctuating between 50 ± 30 and 200 ± 70 days. The shortest mean residence times were measured in a hilly catchment dominated by cropland and rangelands, whereas they were the longest in an undulating catchment dominated by forests and cropland. Calculation of the Be-7/excess-Pb-210 in both rainfall and sediment allowed gaining insight on sediment dynamics throughout the rainy season. The first heavy storms of the year exported the bulk of the sediment stock accumulated in the river channel during the previous year. Then, during the rainy season, the two steeper catchments dominated by cropland and rangelands reacted strongly to rainfall. Sediment was indeed eroded and exported from both catchments during single heavy storms on several occasions in 2009. In contrast, the agro-forested catchment with gentler slopes exported sediment at a constant

  20. 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

  1. 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

  2. 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

  3. Microfabricated Waveguide Atom Traps.

    SciTech Connect

    Jau, Yuan-Yu

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading coldmore » atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.« less

  4. Microfabricated Waveguide Atom Traps.

    SciTech Connect

    Jau, Yuan-Yu

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

  5. RADIOACTIVE RAIN, SNOW AND ATOMSPHERIC CONTAMINATION OBSERVED IN NAGAOKA CITY, JAPAN. REPORT VIII. TOTAL INTENSITIES OF THE RADIOACTIVE FALLOUT DURING THE YEAR 1962(in Japanese)

    SciTech Connect

    Kobayashi, U.; Sasaki, H.

    1963-03-01

    In 1962 the artificial radioactivity of rain, snow, and airborne debris in Nagaoka City due to nuclear detonations was investigated. Because of the interruption of the northern nuclear explosion tests in November 1961, the radioactive fallout diminished month by month until August 1962, but when tests were resumed, it began to increase again and since then has steadily increased. The total amount of fallout from January to October 1962 has already exceeded that of all the year 1958, the highest one till 1961. (auth)

  6. Weathering and the fallout plume of heavy oil from strong petroleum seeps near Coal Oil Point, CA.

    PubMed

    Farwell, Christopher; Reddy, Christopher M; Peacock, Emily; Nelson, Robert K; Washburn, Libe; Valentine, David L

    2009-05-15

    The Coal Oil Point (COP) seeps offshore Goleta, CA, are estimated to release 20-25 tons of oil daily, providing an ideal natural laboratory to investigate the fate of oil in the coastal ocean. To address the long-term fate of COP oil, we collected 15 sediment samples down current from the seeps and quantified petroleum content and individual biomarkers using traditional and comprehensive two-dimensional gas chromatography. Similarities in the distributions of hopane biomarkers link the oil in the sediments to fresh seep oil (n=5) and underlying reservoirs (n=3), although sediment oil is heavily weathered. The spatial distribution of oil forms a plume along the continental shelf that we suggest represents a chronic fallout pattern for heavy oil from the persistent surface slicks; average surface currents appear to modulate the distribution of the fallout over a period of 0.4-5 days. The extent of hydrocarbon loss is consistent for all sediments, indicating a common limit to oil weathering with contributions from evaporation, biodegradation, and dissolution. Considering the amount of oil and quantity of sediment impacted, we estimate a sediment oil burden of 0.3 x 10(12) to 3 x 10(12) g in the study area, equivalent to 8-80 spills of the Exxon Valdez accident of 1989.

  7. 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…

  8. High Atom Number in Microsized Atom Traps

    DTIC Science & Technology

    2015-12-14

    forces on the order of (hbar)(k) (Omega), where Omega is the laser Rabi frequency. We have observed behavior compatible with bichromatic slowing and... Rabi frequency. We have observed behavior compatible with bichromatic slowing and cooling of some atoms in atomic beam. Results were presented at the

  9. 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,…

  10. An Accurate EUV/X-ray Line Ratio Diagnostic

    NASA Astrophysics Data System (ADS)

    Brickhouse, Nancy

    2011-09-01

    We propose to calculate accurate collisional excitation rate data for Fe XVIII. The EUV/X-ray line ratio is of particular interest to stellar coronae and other collisionally ionized sources observed with the Chandra LETG/HRC-S. Comparison of observations of Capella and other stellar coronal sources with predictions from existing atomic theory shows discrepancies of 30% and larger in the EUV/X-ray line ratios for Fe XVIII. With atomic data accurate to 10%, now achievable with atomic theory benchmarked by experiment, this line ratio from a single ionization state is useful for determining electron temperature and/or interstellar absorption.

  11. Hydrogen atom kinetics in capacitively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Nunomura, Shota; Katayama, Hirotaka; Yoshida, Isao

    2017-05-01

    Hydrogen (H) atom kinetics has been investigated in capacitively coupled very high frequency (VHF) discharges at powers of 16-780 mW cm-2 and H2 gas pressures of 0.1-2 Torr. The H atom density has been measured using vacuum ultra violet absorption spectroscopy (VUVAS) with a micro-discharge hollow cathode lamp as a VUV light source. The measurements have been performed in two different electrode configurations of discharges: conventional parallel-plate diode and triode with an intermediate mesh electrode. We find that in the triode configuration, the H atom density is strongly reduced across the mesh electrode. The H atom density varies from ˜1012 cm-3 to ˜1010 cm-3 by crossing the mesh with 0.2 mm in thickness and 36% in aperture ratio. The fluid model simulations for VHF discharge plasmas have been performed to study the H atom generation, diffusion and recombination kinetics. The simulations suggest that H atoms are generated in the bulk plasma, by the electron impact dissociation (e + H2 \\to e + 2H) and the ion-molecule reaction (H2 + + H2 \\to {{{H}}}3+ + H). The diffusion of H atoms is strongly limited by a mesh electrode, and thus the mesh geometry influences the spatial distribution of the H atoms. The loss of H atoms is dominated by the surface recombination.

  12. 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)

  13. Atomizing nozzle and process

    DOEpatents

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1992-06-30

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  14. Atomizing nozzle and process

    DOEpatents

    Anderson, I.E.; Figliola, R.S.; Molnar, H.M.

    1993-07-20

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  15. The spatial distribution of caesium-137 over Northern Ireland from fallout from the Chernobyl nuclear accident

    NASA Astrophysics Data System (ADS)

    Rawlins, B. G.; Scheib, C.; Tyler, A. N.; Jones, D.; Webster, R.; Young, M. E.

    2009-04-01

    The spatial distribution of caesium-137 (137Cs) across the land is of much interest because it can tell us about the redistribution of the radionuclide as a result of soil erosion, differential migration through the soil—or its complement, differential retention in the soil. Any such inferences from survey measurements depend on the assumption of a broadly even distribution from weapons testing fallout, and the substantial deposition of 137Cs in rain following the Chernobyl accident on 26 April 1986. Deposition from the latter was not uniform over large areas, of course, and measurements across northern England showed that the magnitude of 137Cs deposition depended largely on the distribution of convective rainfall in the days immediately after the accident. There were too few measurements of 137Cs deposition at close spacings to estimate local variation. Twenty years after the deposition from Chernobyl a detailed airborne radiometric survey of the whole of Northern Ireland was flown. Flights were made along transects 200 m apart with recordings at 80 m intervals along the flight lines to give more than one million data in total. We have used the data to investigate the spatial distribution of 137Cs. Our initial geostatistical analyses suggested substantial short-range variation in the distribution of 137Cs. We wished to determine whether soil erosion or soil type could account for this. We made further detailed analyses using the terrain parameter compound topographic index as an index of soil erosion and deposition and soil maps to account for the migration or retention of 137Cs. The concentration of 137Cs in the soil is greatest where most rain fell in the few days after the accident. However, the local variances are of similar magnitudes across the the majority of the province. The global variogram of the radionuclide shows a large proportion of the spatially correlated variance occurring within 700 m and a longer-range structure extending to 15 km. Local

  16. 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.

  17. 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

    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 andmore » 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.« less

  18. 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

  19. Materials at Atomic Pressure

    SciTech Connect

    Hicks, Damien

    2010-06-10

    Atomic units give the scale at which quantum processes operate. As combinations of fundamental constants they concisely encapsulate qualities of the atom, e.g. atomic length and energy scales are given by the Bohr radius and the Hartree (or Rydberg) respectively. Although many of these quantities were probed in the early part of the 20th Century the atomic unit of time, at tens of attoseconds, was first probed in 2001. Today, the only atomic unit that remains to be studied experimentally is the atomic unit of pressure, at 294 Mbar (or 147 Mbar in Rydberg atomic units). This is nature’s definition of the ‘high’ in high-pressure science, and it sets the scale for new physics and chemistry. Among experimental facilities, only the NIF can attain and accurately probe atomic pressures. We propose to directly study material properties at these conditions by examining the short-range ordering of atoms using x-ray absorption fine structure spectroscopy (XAFS) of layers in spherical, ignition-type imploding shells. What happens at atomic pressures? The atomic unit of pressure represents the quantum mechanical pressure exerted by an orbiting electron to prevent collapse into the nucleus. Applying external pressure of this magnitude seriously disrupts orbitals and alters the character of the atom itself. Core electron orbitals overlap and chemical bonds are no longer constrained to occur between valence electron orbitals alone. The most direct probe of bonding requires a short-range order diagnostic such as XAFS.

  20. Images of Atoms.

    ERIC Educational Resources Information Center

    Wright, Tony

    2003-01-01

    Recommends using a simple image, such as the fuzzy atom ball to help students develop a useful understanding of the molecular world. Explains that the image helps students easily grasp ideas about atoms and molecules and leads naturally to more advanced ideas of atomic structure, chemical bonding, and quantum physics. (Author/NB)

  1. Atomic Spectra Database (ASD)

    National Institute of Standards and Technology Data Gateway

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  2. Thermoluminescence measurements of gamma-ray doses attributable to fallout from the Nevada test site using building bricks as natural dosimeters.

    PubMed

    Haskell, E H; Bailiff, I K; Kenner, G H; Kaipa, P L; Wrenn, M E

    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(-4) C kg-1 to 26 x 10(-4) C kg-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.

  3. 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).

  4. Compilation of Local Fallout Data from Test Detonations 1945-1962 Extracted from DASA 1251. Volume II-Oceanic U.S. Tests

    DTIC Science & Technology

    1979-05-01

    o• .• .,a• 4 Shot i \\ Brava ., • Romeo plKER*" €R _• • ;t’tuto Miles Union Yankee now fIT LFA ZEBRA WOVIE • . KE...mr/:ir. In contrast to the othcr bar ,yv shots, contamination was also pxbriencod on the .to].]’s southwontcrn i slands. The off-site fallout pattern

  5. Single atom electrochemical and atomic analytics

    NASA Astrophysics Data System (ADS)

    Vasudevan, Rama

    In the past decade, advances in electron and scanning-probe based microscopies have led to a wealth of imaging and spectroscopic data with atomic resolution, yielding substantial insight into local physics and chemistry in a diverse range of systems such as oxide catalysts, multiferroics, manganites, and 2D materials. However, typical analysis of atomically resolved images is limited, despite the fact that image intensities and distortions of the atoms from their idealized positions contain unique information on the physical and chemical properties inherent to the system. Here, we present approaches to data mine atomically resolved images in oxides, specifically in the hole-doped manganite La5/8Ca3/8MnO3, on epitaxial films studied by in-situ scanning tunnelling microscopy (STM). Through application of bias to the STM tip, atomic-scale electrochemistry is demonstrated on the manganite surface. STM images are then further analyzed through a suite of algorithms including 2D autocorrelations, sliding window Fourier transforms, and others, and can be combined with basic thermodynamic modelling to reveal relevant physical and chemical descriptors including segregation energies, existence and strength of atomic-scale diffusion barriers, surface energies and sub-surface chemical species identification. These approaches promise to provide tremendous insights from atomically resolved functional imaging, can provide relevant thermodynamic parameters, and auger well for use with first-principles calculations to yield quantitative atomic-level chemical identification and structure-property relations. This research was sponsored by the Division of Materials Sciences and Engineering, BES, DOE. Research was conducted at the Center for Nanophase Materials Sciences, which also provided support and is a DOE Office of Science User Facility.

  6. Semiparametric regression modeling with mixtures of Berkson and classical error, with application to fallout from the Nevada test site.

    PubMed

    Mallick, Bani; Hoffman, F Owen; Carrol, Raymond J

    2002-03-01

    We construct Bayesian methods for semiparametric modeling of a monotonic regression function when the predictors are measured with classical error. Berkson error, or a mixture of the two. Such methods require a distribution for the unobserved (latent) predictor, a distribution we also model semiparametrically. Such combinations of semiparametric methods for the dose response as well as the latent variable distribution have not been considered in the measurement error literature for any form of measurement error. In addition, our methods represent a new approach to those problems where the measurement error combines Berkson and classical components. While the methods are general, we develop them around a specific application, namely, the study of thyroid disease in relation to radiation fallout from the Nevada test site. We use this data to illustrate our methods, which suggest a point estimate (posterior mean) of relative risk at high doses nearly double that of previous analyses but that also suggest much greater uncertainty in the relative risk.

  7. Sulfide bonded atomic radii

    NASA Astrophysics Data System (ADS)

    Gibbs, G. V.; Ross, N. L.; Cox, D. F.

    2017-09-01

    The bonded radius, r b(S), of the S atom, calculated for first- and second-row non-transition metal sulfide crystals and third-row transition metal sulfide molecules and crystals indicates that the radius of the sulfur atom is not fixed as traditionally assumed, but that it decreases systematically along the bond paths of the bonded atoms with decreasing bond length as observed in an earlier study of the bonded radius of the oxygen atom. When bonded to non-transition metal atoms, r b(S) decreases systematically with decreasing bond length from 1.68 Å when the S atom is bonded to the electropositive VINa atom to 1.25 Å when bonded to the more electronegative IVP atom. In the case of transition metal atoms, rb(S) likewise decreases with decreasing bond length from 1.82 Å when bonded to Cu and to 1.12 Å when bonded to Fe. As r b(S) is not fixed at a given value but varies substantially depending on the bond length and the field strength of the bonded atoms, it is apparent that sets of crystal and atomic sulfide atomic radii based on an assumed fixed radius for the sulfur atom are satisfactory in that they reproduce bond lengths, on the one hand, whereas on the other, they are unsatisfactory in that they fail to define the actual sizes of the bonded atoms determined in terms of the minima in the electron density between the atoms. As such, we urge that the crystal chemistry and the properties of sulfides be studied in terms of the bond lengths determined by adding the radii of either the atomic and crystal radii of the atoms but not in terms of existing sets of crystal and atomic radii. After all, the bond lengths were used to determine the radii that were experimentally determined, whereas the individual radii were determined on the basis of an assumed radius for the sulfur atom.

  8. Hyperthermal atomic oxygen generator

    NASA Technical Reports Server (NTRS)

    Khandelwal, Govind S.; Wu, Dongchuan

    1990-01-01

    Characterization of the transport properties of oxygen through silver was continued. Specifically, experiments measuring the transport through Ag(111), Ag(110), Ag(100) single crystals and through Ag0.05 Zr alloy were completed. In addition, experiments using glow discharge excitation of oxygen to assist in the transport were completed. It was found that the permeability through the different orientations of single crystal Ag was the same, but significant differences existed in the diffusivity. The experimental ratio of diffusivities, however, was in reasonable agreement with theoretical estimates. Since the solubilities of orientations must be the same, this suggests some problems with the assumption K = DS. The glow discharge experiments show that there is a substantial increase in transport (factor of six) when the upstream pressure is dissociated to some fraction of atoms (which have a much higher sticking coefficient). These results indicate that there is a significant surface limitation because of dissociative adsorption of the molecules. Experiments with the Ag0.05 Zr alloy and its high-grain boundary and defect density show a permeability of greater than a factor of two over ordinary polycrystalline Ag, but it is unclear as to whether this is because of enhanced transport through these defects or whether the Zr and defects on the surface increased the sticking coefficient and therefore the transport.

  9. 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

  10. 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.

  11. Assumptions and challenges in the use of fallout beryllium-7 as a soil and sediment tracer in river basins

    NASA Astrophysics Data System (ADS)

    Taylor, A.; Blake, W. H.; Smith, H. G.; Mabit, L.; Keith-Roach, M. J.

    2013-11-01

    This contribution reviews research surrounding the assumptions that underpin the use of beryllium-7 (7Be) as a soil and sediment tracer in river basins. As a cosmogenic radionuclide, the constant natural production of 7Be and fallout via precipitation, coupled with its ability to bind to soil and sediment particles provides the basis for its application as a conservative soil and sediment tracer. Consequently, 7Be has been extensively employed as a tracer across a range of spatial and temporal (event to seasonal) scales. The short half-life of 7Be (53.3 days) lends itself to tracing sediment dynamics over short time periods, thus, providing complementary data to medium-term estimates derived from longer lived radionuclides such as caesium-137 (137Cs). This short half-life could provide a major advantage when considering the potential for 7Be to document recent effects of climate or land use change upon soil redistribution, with the latter having particular relevance for assessing the effectiveness of mitigating strategies within a catchment-wide approach to management. Although 7Be has been widely applied as a tracer to date, application is still in its infancy and there remains a lack of knowledge in relation to the assumptions for its use as a tracer. Specifically, our findings suggest that there are crucial information gaps with regard to 7Be application as an erosion tracer. Of key importance is the potential for fallout uniformity and rapid tracer sorption to be compromised under certain conditions. The assumption of irreversible sorption is likely to hold for common hillslope conditions but literature identifies the potential for tracer mobility with changing environmental parameters in the wider catchment. Further research is required to determine the likelihood of 7Be sorption being affected by conditions found at relevant field sites and the impact of this upon tracer applications at the catchment-scale.

  12. Distribution of artificial radionuclides in particle-size fractions of soil on fallout plumes of nuclear explosions.

    PubMed

    Kabdyrakova, A M; Lukashenko, S N; Mendubaev, A T; Kunduzbayeva, A Ye; Panitskiy, A V; Larionova, N V

    2018-06-01

    In this paper are analyzed the artificial radionuclide distributions ( 137 Cs, 90 Sr, 241 Am, 239+240 Pu) in particle-size fractions of soils from two radioactive fallout plumes at the Semipalatinsk Test Site. These plumes were generated by a low-yield surface nuclear test and a surface non-nuclear experiment with insignificant nuclear energy release, respectively, and their lengths are approximately 3 and 0,65 km. In contrast with the great majority of similar studies performed in areas affected mainly by global fallout where adsorbing radionuclides such as Pu are mainly associated with the finest soil fractions, in this study it was observed that along both analyzed plumes the highest activity concentrations are concentrated in the coarse soil fractions. At the plume generated by the surface nuclear test, the radionuclides are concentrated mainly in the 1000-500 μm soil fraction (enrichment factor values ranging from 1.2 to 3.8), while at the plume corresponding to the surface non-nuclear test is the 500-250 μm soil fraction the enriched one by technogenic radionuclides (enrichment factor values ranging from 1.1 to 5.1). In addition, the activity concentration distributions among the different soil size fractions are similar for all radionuclides in both plumes. All the obtained data are in agreement with the hypothesis indicating that enrichment observed in the coarse fractions is caused by the presence of radioactive particles resulted from the indicated nuclear tests. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Are dietary reports in a case-control study on thyroid cancer biased by risk perception of Chernobyl fallout?

    PubMed

    Xhaard, C; Dumas, A; Souchard, V; Ren, Y; Borson-Chazot, F; Sassolas, G; Schvartz, C; Colonna, M; Lacour, B; Wonoroff, A S; Velten, M; Clero, E; Maillard, S; Marrer, E; Bailly, L; Mariné Barjoan, E; Schlumberger, M; Orgiazzi, J; Adjadj, E; Rubino, C; Bouville, A; Drozdovitch, V; de Vathaire, F

    2017-08-01

    In retrospective case-control studies performed following nuclear tests or nuclear accidents, individual thyroid radiation dose reconstructions are based on fallout and meteorological data from the residential area, demographic characteristics, and lifestyle as well as dietary information. Collecting the latter is a controversial step, as dietary declarations may be affected by the subjects' beliefs about their risk behavior. This report analyses the potential for such bias in a case-control study performed in eastern France. The study included 765 cases of differentiated thyroid carcinoma matched with 831 controls. Risk perceptions and beliefs of cases and controls were compared using Chi 2 tests and differences in dietary reports were analyzed using a two-way ANOVA. In general, atmospheric pollution and living near a nuclear power plant were the two major risks that may influence thyroid cancer occurrence cited by cases and controls. When focusing in particular on the consequences of the Chernobyl accident, cases were more likely to think that the consequences were responsible for thyroid cancer occurrence than controls. Vegetable consumption during the two months after the Chernobyl accident was correlated with the status of subjects, but not to their beliefs. Conversely, consumption of fresh dairy products was not correlated with the status or beliefs of subjects. We found no evidence of systematic bias in dietary reports according to the status or beliefs held by subjects about the link between thyroid cancer occurrence and Chernobyl fallout. As such, these dietary reports may be used in further studies involving individual dosimetric reconstructions. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. 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

  15. Modeling the early-phase redistribution of radiocesium fallouts in an evergreen coniferous forest after Chernobyl and Fukushima accidents.

    PubMed

    Calmon, P; Gonze, M-A; Mourlon, Ch

    2015-10-01

    Following the Chernobyl accident, the scientific community gained numerous data on the transfer of radiocesium in European forest ecosystems, including information regarding the short-term redistribution of atmospheric fallout onto forest canopies. In the course of international programs, the French Institute for Radiological Protection and Nuclear Safety (IRSN) developed a forest model, named TREE4 (Transfer of Radionuclides and External Exposure in FORest systems), 15 years ago. Recently published papers on a Japanese evergreen coniferous forest contaminated by Fukushima radiocesium fallout provide interesting and quantitative data on radioactive mass fluxes measured within the forest in the months following the accident. The present study determined whether the approach adopted in the TREE4 model provides satisfactory results for Japanese forests or whether it requires adjustments. This study focused on the interception of airborne radiocesium by forest canopy, and the subsequent transfer to the forest floor through processes such as litterfall, throughfall, and stemflow, in the months following the accident. We demonstrated that TREE4 quite satisfactorily predicted the interception fraction (20%) and the canopy-to-soil transfer (70% of the total deposit in 5 months) in the Tochigi forest. This dynamics was similar to that observed in the Höglwald spruce forest. However, the unexpectedly high contribution of litterfall (31% in 5 months) in the Tochigi forest could not be reproduced in our simulations (2.5%). Possible reasons for this discrepancy are discussed; and sensitivity of the results to uncertainty in deposition conditions was analyzed. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Collisional Cooling of Light Ions by Cotrapped Heavy Atoms.

    PubMed

    Dutta, Sourav; Sawant, Rahul; Rangwala, S A

    2017-03-17

    We experimentally demonstrate cooling of trapped ions by collisions with cotrapped, higher-mass neutral atoms. It is shown that the lighter ^{39}K^{+} ions, created by ionizing ^{39}K atoms in a magneto-optical trap (MOT), when trapped in an ion trap and subsequently allowed to cool by collisions with ultracold, heavier ^{85}Rb atoms in a MOT, exhibit a longer trap lifetime than without the localized ^{85}Rb MOT atoms. A similar cooling of trapped ^{85}Rb^{+} ions by ultracold ^{133}Cs atoms in a MOT is also demonstrated in a different experimental configuration to validate this mechanism of ion cooling by localized and centered ultracold neutral atoms. Our results suggest that the cooling of ions by localized cold atoms holds for any mass ratio, thereby enabling studies on a wider class of atom-ion systems irrespective of their masses.

  17. 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…

  18. Atomization characteristics of coal-water mixtures

    SciTech Connect

    Krishna, C.R.; Marnell, P.; Butcher, T.A.

    1982-01-01

    There is very little published information on the atomization of coal-water fuels where the presence of solid particles with their own size distribution is expected to affect the process of liquid breakup. This paper presents results obtained on the air atomization of coal-water fuels. A standard air atomizer was used in the experiments. A Malvern particle sizer was used to acquire the drop size distribution. The drop size was measured as a function of the key atomizer parameters, namely, the air pressure and the ratio of fuel and atomizing air mass flow rates. Measurements were made using water to givemore » the baseline and a coal-water mixture with 33 percent of weight coal. Some of the important conclusions are: (1) At similar atomizing conditions (that is, same air pressure and fuel to air mass flow ratio), the mass median diameter for the coal-water mixture was consistently less than that for the water. (2) The difference noted above decreased for low fuel/air mass flow; that is, when the mean diameter became small. (3) The size distribution in both cases seemed to fit well a Rosin-Rammler distribution (within the accuracy of measurement).« less

  19. Atomic Oxygen Effects

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K. R.

    2014-01-01

    Atomic oxygen, which is the most predominant species in low Earth orbit, is highly reactive and can break chemical bonds on the surface of a wide variety of materials leading to volatilization or surface oxidation which can result in failure of spacecraft materials and components. This presentation will give an overview of how atomic oxygen reacts with spacecraft materials, results of space exposure testing of a variety of materials, and examples of failures caused by atomic oxygen.

  20. Atomicity in Electronic Commerce,

    DTIC Science & Technology

    1996-01-01

    tremendous demand for the ability to electronically buy and sell goods over networks. Electronic commerce has inspired a large variety of work... commerce . It then briefly surveys some major types of electronic commerce pointing out flaws in atomicity. We pay special attention to the atomicity...problems of proposals for digital cash. The paper presents two examples of highly atomic electronic commerce systems: NetBill and Cryptographic Postage Indicia.

  1. Advances in atomic physics

    PubMed Central

    El-Sherbini, Tharwat M.

    2013-01-01

    In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research – an overview is provided of the milestones in the fascinating landscape of atomic physics. PMID:26425356

  2. Metal atom oxidation laser

    DOEpatents

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides.

  3. Metal atom oxidation laser

    DOEpatents

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides. (auth)

  4. Atomic switch: atom/ion movement controlled devices for beyond von-neumann computers.

    PubMed

    Hasegawa, Tsuyoshi; Terabe, Kazuya; Tsuruoka, Tohru; Aono, Masakazu

    2012-01-10

    An atomic switch is a nanoionic device that controls the diffusion of metal ions/atoms and their reduction/oxidation processes in the switching operation to form/annihilate a conductive path. Since metal atoms can provide a highly conductive channel even if their cluster size is in the nanometer scale, atomic switches may enable downscaling to smaller than the 11 nm technology node, which is a great challenge for semiconductor devices. Atomic switches also possess novel characteristics, such as high on/off ratios, very low power consumption and non-volatility. The unique operating mechanisms of these devices have enabled the development of various types of atomic switch, such as gap-type and gapless-type two-terminal atomic switches and three-terminal atomic switches. Novel functions, such as selective volatile/nonvolatile, synaptic, memristive, and photo-assisted operations have been demonstrated. Such atomic switch characteristics can not only improve the performance of present-day electronic systems, but also enable development of new types of electronic systems, such as beyond von- Neumann computers. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Improved graphite furnace atomizer

    DOEpatents

    Siemer, D.D.

    1983-05-18

    A graphite furnace atomizer for use in graphite furnace atomic absorption spectroscopy is described wherein the heating elements are affixed near the optical path and away from the point of sample deposition, so that when the sample is volatilized the spectroscopic temperature at the optical path is at least that of the volatilization temperature, whereby analyteconcomitant complex formation is advantageously reduced. The atomizer may be elongated along its axis to increase the distance between the optical path and the sample deposition point. Also, the atomizer may be elongated along the axis of the optical path, whereby its analytical sensitivity is greatly increased.

  6. From Atoms to Solids

    DTIC Science & Technology

    1999-01-31

    order to distinguish them from, for example, 4. Shells of atoms the regular shells of an icosahedron where atoms must be added to all faces in order to...heavy lines. This figure can be found in shells of Fig. 5. A closed-shell 55 atom icosahedron and a portion of the increasing size. next shell. T.P... icosahedron , then the total mass peaks does not allow us to distinguish between number of atoms N, in a cluster containing K shells these two structures

  7. Visualization of atom's orbits.

    PubMed

    Kim, Byungwhan

    2014-02-01

    High-resolution imaging techniques have been used to obtain views of internal shapes of single atoms or columns of atoms. This review article focuses on the visualization of internal atomic structures such as the configurations of electron orbits confined to atoms. This is accomplished by applying visualization techniques to the reported images of atoms or molecules as well as static and dynamic ions in a plasma. It was found that the photon and electron energies provide macroscopic and microscopic views of the orbit structures of atoms, respectively. The laser-imaged atoms showed a rugged orbit structure, containing alternating dark and bright orbits believed to be the pathways for an externally supplied laser energy and internally excited electron energy, respectively. By contrast, the atoms taken by the electron microscopy provided a structure of fine electron orbits, systematically formed in increasing order of grayscale representing the energy state of an orbit. This structure was identical to those of the plasma ions. The visualized electronic structures played a critical role in clarifying vague postulates made in the Bohr model. Main features proposed in the atomic model are the dynamic orbits absorbing an externally supplied electromagnetic energy, electron emission from them while accompanying light radiation, and frequency of electron waves not light. The light-accompanying electrons and ionic speckles induced by laser light signify that light is composed of electrons and ions.

  8. 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.

  9. Atomic Oxygen Fluence Monitor

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.

    2011-01-01

    This innovation enables a means for actively measuring atomic oxygen fluence (accumulated atoms of atomic oxygen per area) that has impinged upon spacecraft surfaces. Telemetered data from the device provides spacecraft designers, researchers, and mission managers with real-time measurement of atomic oxygen fluence, which is useful for prediction of the durability of spacecraft materials and components. The innovation is a compact fluence measuring device that allows in-space measurement and transmittance of measured atomic oxygen fluence as a function of time based on atomic oxygen erosion yields (the erosion yield of a material is the volume of material that is oxidized per incident oxygen atom) of materials that have been measured in low Earth orbit. It has a linear electrical response to atomic oxygen fluence, and is capable of measuring high atomic oxygen fluences (up to >10(exp 22) atoms/sq cm), which are representative of multi-year low-Earth orbital missions (such as the International Space Station). The durability or remaining structural lifetime of solar arrays that consist of polymer blankets on which the solar cells are attached can be predicted if one knows the atomic oxygen fluence that the solar array blanket has been exposed to. In addition, numerous organizations that launch space experiments into low-Earth orbit want to know the accumulated atomic oxygen fluence that their materials or components have been exposed to. The device is based on the erosion yield of pyrolytic graphite. It uses two 12deg inclined wedges of graphite that are over a grit-blasted fused silica window covering a photodiode. As the wedges erode, a greater area of solar illumination reaches the photodiode. A reference photodiode is also used that receives unobstructed solar illumination and is oriented in the same direction as the pyrolytic graphite covered photodiode. The short-circuit current from the photodiodes is measured and either sent to an onboard data logger, or

  10. New atomic data for Fe/+19/

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Mason, H. E.

    1980-01-01

    New atomic data are tabulated for Fe(+19). The electron collision strengths are calculated using the 'distorted wave' approximation and results are presented for several energies of the exciting electron. The populations of the ground levels are calculated as a function of electron density under conditions appropriate to solar flares and tokamak plasmas. Theoretical intensity ratios are tabulated for the UV lines.

  11. Precision mass ratios of mass-3 ions

    NASA Astrophysics Data System (ADS)

    Myers, Edmund G.; Hamzeloui, Saeed; Smith, Jordan R.; Fink, David J.

    2017-04-01

    Precision atomic masses of hydrogen, deuterium and helium-3 are important fundamental constants with application to a wide range of physical science. Using a rebuilt and improved Penning trap mass spectrometer, we are measuring the ion mass ratios HD+/H3+, 3He+/H3+ and 3He+/HD+. The results will help resolve the current four-sigma discrepancy for the mass of 3He. Work supported by NSF.

  12. Wave mechanics of a two-wire atomic beam splitter

    SciTech Connect

    Bortolotti, Daniele C.E.; Bohn, John L.

    2004-03-01

    We consider the problem of an atomic beam propagating quantum mechanically through an atom beam splitter. Casting the problem in an adiabatic representation (in the spirit of the Born-Oppenheimer approximation in molecular physics) sheds light on explicit effects due to nonadiabatic passage of the atoms through the splitter region. We are thus able to probe the fully three-dimensional structure of the beam splitter, gathering quantitative information about mode mixing, splitting ratios, and reflection and transmission probabilities.

  13. Polymeric Materials Resistant to Erosion by Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.; Thibeault, Sheila A.

    2004-01-01

    Polymer-matrix composites are ideally suited for space vehicles because of high strength to weight ratios. The principal component of the low earth orbit (LEO) is atomic oxygen. Atomic oxygen causes surface erosion to polymeric materials. Polymer films with an organometallic additive showed greater resistance to atomic oxygen than the pure polymer in laboratory experiments and in the OPM/MIR experiment. In MISSE, the film with the organometallic additive was still intact after the pure film had completely eroded.

  14. Equilibrium vortex lattices of a binary rotating atomic Bose–Einstein condensate with unequal atomic masses

    SciTech Connect

    Dong, Biao; Wang, Lin-Xue; Chen, Guang-Ping; Han, Wei; Zhang, Shou-Gang; Zhang, Xiao-Fei

    2016-10-15

    We perform a detailed numerical study of the equilibrium ground-state structures of a binary rotating Bose–Einstein condensate with unequal atomic masses. Our results show that the ground-state distribution and its related vortex configurations are complex events that differ markedly depending strongly on the strength of rotation frequency, as well as on the ratio of atomic masses. We also discuss the structures and radii of the clouds, the number and the size of the core region of the vortices, as a function of the rotation frequency, and of the ratio of atomic masses, and the analytical results agree well with our numerical simulations. This work may open an alternate way in the quantum control of the binary rotating quantum gases with unequal atomic masses. - Highlights: • A binary quantum gases with unequal atomic masses is considered. • Effects of the ratio of atomic masses and rotation frequency are discussed in full parameter space. • The detailed information about both the cloud and vortices are also discussed.

  15. Equilibrium vortex lattices of a binary rotating atomic Bose–Einstein condensate with unequal atomic masses

    SciTech Connect

    Dong, Biao; Wang, Lin-Xue; Chen, Guang-Ping

    2016-10-15

    We perform a detailed numerical study of the equilibrium ground-state structures of a binary rotating Bose–Einstein condensate with unequal atomic masses. Our results show that the ground-state distribution and its related vortex configurations are complex events that differ markedly depending strongly on the strength of rotation frequency, as well as on the ratio of atomic masses. We also discuss the structures and radii of the clouds, the number and the size of the core region of the vortices, as a function of the rotation frequency, and of the ratio of atomic masses, and the analytical results agree well with ourmore » numerical simulations. This work may open an alternate way in the quantum control of the binary rotating quantum gases with unequal atomic masses. - Highlights: • A binary quantum gases with unequal atomic masses is considered. • Effects of the ratio of atomic masses and rotation frequency are discussed in full parameter space. • The detailed information about both the cloud and vortices are also discussed.« less

  16. When Atoms Want

    ERIC Educational Resources Information Center

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  17. Atomic Power Safety.

    ERIC Educational Resources Information Center

    Hogerton, John F.

    This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: What is Atomic Power?; What Does Safety Depend On?; Control of Radioactive Material During Operation; Accident Prevention; Containment in the Event of an Accident; Licensing and…

  18. Liquid-Seeding Atomizer

    NASA Technical Reports Server (NTRS)

    Seegmiller, Henry L. B.

    1988-01-01

    Particles sprayed in drops of evaporating liquid. Placed near wind-tunnel inlet, atomizer sprays evaporating liquid containing solid particles into wind-tunnel airflow. Particles entrained in flow and scatter light, enabling flow to be observed optically. One end of atomizer slides on stationary pin to accommodate thermal expansion and contraction.

  19. Atom Interferometry Progress

    DTIC Science & Technology

    1990-04-19

    microns. The first two gratings separate and redirect the atomic beam forming a standing wave interference pattern in the atomic flux at the third...grating, which acts like a mask to sample this pattern. A principle technical obstacle is the mechanical vibrations of our machine which will blur the interference pattern .

  20. The Ratio Table.

    ERIC Educational Resources Information Center

    Middleton, James A.; Heuvel-Panhuizen, Marja van den

    1995-01-01

    Examines the use of a ratio table for developing students' conceptual understanding of rational number. The ratio table is an alternative to cross-multiplication and can utilize both additive and multiplicative strategies. It organizes numbers and keeps track of operations and results, which aids the teacher in assessment. (MLB)

  1. Compression Ratio Adjuster

    NASA Technical Reports Server (NTRS)

    Akkerman, J. W.

    1982-01-01

    New mechanism alters compression ratio of internal-combustion engine according to load so that engine operates at top fuel efficiency. Ordinary gasoline, diesel and gas engines with their fixed compression ratios are inefficient at partial load and at low-speed full load. Mechanism ensures engines operate as efficiently under these conditions as they do at highload and high speed.

  2. Coaxial airblast atomizers

    NASA Technical Reports Server (NTRS)

    Hardalupas, Y.; Whitelaw, J. H.

    1993-01-01

    An experimental investigation was performed to quantify the characteristics of the sprays of coaxial injectors with particular emphasis on those aspects relevant to the performance of rocket engines. Measurements for coaxial air blast atomizers were obtained using air to represent the gaseous stream and water to represent the liquid stream. A wide range of flow conditions were examined for sprays with and without swirl for gaseous streams. The parameters varied include Weber number, gas flow rate, liquid flow rate, swirl, and nozzle geometry. Measurements were made with a phase Doppler velocimeter. Major conclusions of the study focused upon droplet size as a function of Weber number, effect of gas flow rate on atomization and spray spread, effect of nozzle geometry on atomization and spread, effect of swirl on atomization, spread, jet recirculation and breakup, and secondary atomization.

  3. Coaxial airblast atomizers

    NASA Astrophysics Data System (ADS)

    Hardalupas, Y.; Whitelaw, J. H.

    1993-05-01

    An experimental investigation was performed to quantify the characteristics of the sprays of coaxial injectors with particular emphasis on those aspects relevant to the performance of rocket engines. Measurements for coaxial air blast atomizers were obtained using air to represent the gaseous stream and water to represent the liquid stream. A wide range of flow conditions were examined for sprays with and without swirl for gaseous streams. The parameters varied include Weber number, gas flow rate, liquid flow rate, swirl, and nozzle geometry. Measurements were made with a phase Doppler velocimeter. Major conclusions of the study focused upon droplet size as a function of Weber number, effect of gas flow rate on atomization and spray spread, effect of nozzle geometry on atomization and spread, effect of swirl on atomization, spread, jet recirculation and breakup, and secondary atomization.

  4. Optimization of Neutral Atom Imagers

    NASA Technical Reports Server (NTRS)

    Shappirio, M.; Coplan, M.; Balsamo, E.; Chornay, D.; Collier, M.; Hughes, P.; Keller, J.; Ogilvie, K.; Williams, E.

    2008-01-01

    The interactions between plasma structures and neutral atom populations in interplanetary space can be effectively studied with energetic neutral atom imagers. For neutral atoms with energies less than 1 keV, the most efficient detection method that preserves direction and energy information is conversion to negative ions on surfaces. We have examined a variety of surface materials and conversion geometries in order to identify the factors that determine conversion efficiency. For chemically and physically stable surfaces smoothness is of primary importance while properties such as work function have no obvious correlation to conversion efficiency. For the noble metals, tungsten, silicon, and graphite with comparable smoothness, conversion efficiency varies by a factor of two to three. We have also examined the way in which surface conversion efficiency varies with the angle of incidence of the neutral atom and have found that the highest efficiencies are obtained at angles of incidence greater then 80deg. The conversion efficiency of silicon, tungsten and graphite were examined most closely and the energy dependent variation of conversion efficiency measured over a range of incident angles. We have also developed methods for micromachining silicon in order to reduce the volume to surface area over that of a single flat surface and have been able to reduce volume to surface area ratios by up to a factor of 60. With smooth micro-machined surfaces of the optimum geometry, conversion efficiencies can be increased by an order of magnitude over instruments like LENA on the IMAGE spacecraft without increase the instruments mass or volume.

  5. Deposition and distribution of Chernobyl fallout fission products and actinides in a Russian soil profile.

    PubMed

    Carbol, P; Solatie, D; Erdmann, N; Nylén, T; Betti, M

    2003-01-01

    In this article the distribution of fission products and actinides in a soil profile from Novo Bobovicky in Russia, which was contaminated due to the Chernobyl nuclear power plant accident, is described. The ground deposition of long-lived fission products determined by gamma-spectrometry was (recalculated to 26 April 1986) 1600 kBq (137)Cs/m(2), 900 kBq (134)Cs/m(2) and 60 kBq (125)Sb/m(2). Of these radionuclides (137)Cs shows the dominating activity at the present time. After 6.5 years 90% of the Cs and Sb activity was contained in the upper 4 cm. A (239,240)Pu ground deposition of 77.4+/-8.0 Bq/m(2) was determined by alpha-spectrometry. The (238)Pu/(239,240)Pu activity ratio of 0.30+/-0.03 and (241)Pu/(239,240)Pu activity ratio of 115+/-14 (in 1986) measured in the soil profile, indicates that the analysed Pu originates mainly from the Chernobyl accident. The average (234)U/(238)U activity ratio of 1.06+/-0.29 indicates that the uranium in this soil is dominated by naturally occurring uranium. The alpha- and beta-autoradiography revealed that the activity is mainly present in particulate form. It could further be observed that the spots containing alpha- or beta-activity originated from different particles. A comparison of alpha-autoradiography with the bulk Pu and Am activity showed that 92% of the alpha-activity was present as clearly detectable alpha-spots. The beta-active particles, located by beta-autoradiography were correlated with gamma-spectrometric measurements and contained only (137)Cs. These hot spots ranged from 0.02 to 0.15 Bq.It could be concluded that the vertical transport of (137)Cs and fuel fragments occurs mainly by movement of particles through the soil. It could also be concluded that the fuel fragments found, in this soil were depleted in respect to Cs, Sb and Eu. Comparison of the analysed (238)Pu/(239,240)Pu, (241)Pu/(239,240)Pu and (241)Am/(239,240)Pu ratios with the ratios calculated with ORIGEN-S code gave an estimate of the average

  6. Atomic simulation of cracks under mixed mode loading

    NASA Technical Reports Server (NTRS)

    Mullins, M.

    1984-01-01

    A discrete atomic model of a crack tip in iron under mixed mode loads is examined. The results indicate that the behavior of the crack at the atomic scale as a function of the ratio of mode I to mode II component of load is quite complex. In general, crack tip plasticity appears to increase as the mode II component of load increases.

  7. 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

  8. 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

  9. 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

  10. 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

  11. Modelling the external radiation exposure from the Chernobyl fallout using data from the Swedish municipality measurement system.

    PubMed

    Jönsson, Mattias; Tondel, Martin; Isaksson, Mats; Finck, Robert; Wålinder, Robert; Mamour, Afrah; Rääf, Christopher

    2017-11-01

    In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of 137 Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on these datasets, a model of the time pattern of the external dose rate in terms of ambient dose equivalent rate from the Chernobyl fallout was developed. The decrease in the ambient dose equivalent rate could, on average, be described by a four-component exponential decay function with effective half-times of 6.8 ± 0.3 d, 104 ± 26 d, 1.0 ± 0.02 y and 5.5 ± 0.09 y, respectively. The predominant contributions to the external dose rate in the first month were from short-lived fission products superseded by 134 Cs and then 137 Cs. Integrated over 70 y and using extrapolation of the curve fits, our model predicts that 137 Cs contributes about 60% and 134 Cs contributes about 30% of the external effective dose at these seven locations. The projected time-integrated 70 y external effective dose to an unshielded person from all nuclides per unit total activity deposition of 137 Cs is estimated to be 0.29 ± 0.0.08 mSv/(kBq m -2 ). These results are in agreement with those found in Chernobyl contaminated Russian forest areas, and emphasize the usefulness of maintaining a long-term and regular measurement program in contaminated areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Americium, plutonium and uranium contamination and speciation in well waters, streams and atomic lakes in the Sarzhal region of the Semipalatinsk Nuclear Test Site, Kazakhstan.

    PubMed

    León Vintró, L; Mitchell, P I; Omarova, A; Burkitbayev, M; Jiménez Nápoles, H; Priest, N D

    2009-04-01

    New data are reported on the concentrations, isotopic composition and speciation of americium, plutonium and uranium in surface and ground waters in the Sarzhal region of the Semipalatinsk Test Site, and an adjacent area including the settlement of Sarzhal. The data relate to filtered water and suspended particulate from (a) streams originating in the Degelen Mountains, (b) the Tel'kem 1 and Tel'kem 2 atomic craters, and (c) wells on farms located within the study area and at Sarzhal. The measurements show that (241)Am, (239,240)Pu and (238)U concentrations in well waters within the study area are in the range 0.04-87mBq dm(-3), 0.7-99mBq dm(-3), and 74-213mBq dm(-3), respectively, and for (241)Am and (239,240)Pu are elevated above the levels expected solely on the basis of global fallout. Concentrations in streams sourced in the Degelen Mountains are similar, while concentrations in the two water-filled atomic craters are somewhat higher. Suspended particulate concentrations in well waters vary considerably, though median values are very low, at 0.01mBq dm(-3), 0.08mBq dm(-3) and 0.32mBq dm(-3) for (241)Am, (239,240)Pu and (238)U, respectively. The (235)U/(238)U isotopic ratio in almost all well and stream waters is slightly elevated above the 'best estimate' value for natural uranium worldwide, suggesting that some of the uranium in these waters is of test-site provenance. Redox analysis shows that on average most of the plutonium present in the microfiltered fraction of these waters is in a chemically reduced form (mean 69%; 95% confidence interval 53-85%). In the case of the atomic craters, the proportion is even higher. As expected, all of the americium present appears to be in a reduced form. Calculations suggest that annual committed effective doses to individual adults arising from the daily ingestion of these well waters are in the range 11-42microSv (mean 21microSv). Presently, the ground water feeding these wells would not appear to be contaminated with

  13. A new general mechanistic river model for radionuclides from single pulse fallouts which can be run by readily accessible driving variables.

    PubMed

    Håkanson, Lars

    2005-01-01

    This paper presents a new general, process-based river model for substances such as radionuclides from single pulse fallouts. The new model has been critically tested using data from 13 European rivers contaminated by radiocesium from the Chernobyl accident. This modelling approach gives radionuclide concentrations in water (total, dissolved and particulate phases; and also concentrations in sediments and fish, but the latter aspects are not discussed in this paper) at defined river sites. The model is based on processes in the upstream river stretch and in the upstream catchment area. The catchment area is differentiated into inflow ( approximately dry land) areas and outflow ( approximately wetland) areas. The model also accounts for time-dependent fixation of substances in the catchment. The catchment area sub-model is based on a previous catchment model, which has been tested with very good results for radiocesium, radiostrontium and Ca-concentrations (from liming operations). The new river model 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, continentality, catchment area, mean annual precipitation, soil type (percentages or organic and sandy soils), fallout and month of fallout. Modelled values have been compared to independent empirical data from 10 rivers sites (91 data on radiocesium in water) covering a wide domain (catchment areas from 4000 to 180 000 km(2), precipitation from 500 to 960 mm/yr and fallout from 1700 to 660 000 Bq/m(2)). The new model predicts very well--when modelled values are compared to empirical data, the slope is perfect (1.0) and the r(2)-value is 0.90. This is good giving the fact that there are also uncertainties in the empirical data, which set a limit to the achieved predictive power, as expressed by the r(2)-value.

  14. Rapid Debris Analysis Project Task 3 Final Report - Sensitivity of Fallout to Source Parameters, Near-Detonation Environment Material Properties, Topography, and Meteorology

    SciTech Connect

    Goldstein, Peter

    2014-01-24

    This report describes the sensitivity of predicted nuclear fallout to a variety of model input parameters, including yield, height of burst, particle and activity size distribution parameters, wind speed, wind direction, topography, and precipitation. We investigate sensitivity over a wide but plausible range of model input parameters. In addition, we investigate a specific example with a relatively narrow range to illustrate the potential for evaluating uncertainties in predictions when there are more precise constraints on model parameters.

  15. 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.

  16. VCSELs for atomic clocks

    NASA Astrophysics Data System (ADS)

    Serkland, Darwin K.; Peake, Gregory M.; Geib, Kent M.; Lutwak, Robert; Garvey, R. Michael; Varghese, Mathew; Mescher, Mark

    2006-02-01

    The spectroscopic technique of coherent population trapping (CPT) enables an all-optical interrogation of the groundstate hyperfine splitting of cesium (or rubidium), compared to the optical-microwave double resonance technique conventionally employed in atomic frequency standards. All-optical interrogation enables the reduction of the size and power consumption of an atomic clock by two orders of magnitude, and vertical-cavity surface-emitting lasers (VCSELs) are preferred optical sources due to their low power consumption and circular output beam. Several research teams are currently using VCSELs for DARPA's chip-scale atomic clock (CSAC) program with the goal of producing an atomic clock having a volume < 1 cm^3, a power consumption < 30 mW, and an instability (Allan deviation) < 1x10^-11 during a 1-hour averaging interval. This paper describes the VCSEL requirements for CPT-based atomic clocks, which include single mode operation, single polarization operation, modulation bandwidth > 4 GHz, low power consumption (for the CSAC), narrow linewidth, and low relative intensity noise (RIN). A significant manufacturing challenge is to reproducibly obtain the required wavelength at the specified VCSEL operating temperature and drive current. Data are presented that show the advantage of operating at the D1 (rather than D2) resonance of the alkali atoms. Measurements of VCSEL linewidth will be discussed in particular, since atomic clock performance is especially sensitive to this parameter.

  17. Modeling the spatial distribution of AD 79 pumice fallout and pyroclastic density current and derived deposits of Somma-Vesuvius (Campania, Italy) integrating primary deposition and secondary redistribution

    NASA Astrophysics Data System (ADS)

    Vogel, Sebastian; Märker, Michael

    2013-12-01

    The spatial distributions of primary deposits and related reworked ones from Plinian fallout and from pyroclastic density currents (PDCs) of the AD 79 eruption of Somma-Vesuvius were independently modeled for the Sarno River plain (Campania, Italy). The simulation takes into consideration both primary deposition of the volcanic products and their secondary redistribution by geomorphic processes of erosion, transport, and redeposition. We hypothesize that the pre-eruption topography controlled both the intial volcanic deposition of PDCs and the subsequent processes redistributing material of the pumice fallout and PDC deposits, and thus significantly controlled the thickness of the final volcaniclastic deposits. The methodology applied is based on a reconstructed pre-AD 79 digital elevation model of the Sarno River plain, an extensive tephrostratigraphic dataset from about 1,200 core drillings and a predictive modeling technique. The two models produce contrasting spatial distribution patterns for both the AD 79 deposits from fallout plus their derivates, versus from PDCs and their derivatives. The contrast allows determination of the most important factors controlling the thickness of the AD 79 volcaniclastic deposits. This provides new insights into the process dynamics during and immediately after the AD 79 Plinian eruption including primary deposition, erosion, and redistribution.

  18. 78 FR 58571 - Maine Yankee Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-24

    ... Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic Electric Company... Power Company (Maine Yankee), Connecticut Yankee Atomic Power Company (Connecticut Yankee), and the Yankee Atomic Electric Company (Yankee Atomic) (together, ``licensees'' or ``the Yankee Companies'') from...

  19. 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.

  20. 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 bymore » 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.« less

  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. 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 ofmore » 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.« less

  5. Transfer of fallout radionuclides derived from Fukushima NPP accident: 1 year study on transfer of radionuclides through hydrological processes

    NASA Astrophysics Data System (ADS)

    Onda, Yuichi; Kato, Hiroaki; Patin, Jeremy; Yoshimura, Kazuya; Tsujimura, Maki; Wakahara, Taeko; Fukushima, Takehiko

    2013-04-01

    Previous experiences such as Chernobyl Nuclear Power Plant accident have confirmed that fallout radionuclides on the ground surface migrate through natural environment including soils and rivers. Therefore, in order to estimate future changes in radionuclide deposition, migration process of radionuclides in forests, soils, ground water, rivers should be monitored. However, such comprehensive studies on migration through forests, soils, ground water and rivers have not been conducted so far. Here, we present the following comprehensive investigation was conducted to confirm migration of radionuclides through natural environment including soils and rivers. 1)Study on depth distribution of radiocaesium in soils within forests, fields, and grassland 2)Confirmation of radionuclide distribution and investigation on migration in forests 3)Study on radionuclide migration due to soil erosion under different land use 4)Measurement of radionuclides entrained from natural environment including forests and soils 5)Investigation on radionuclide migration through soil water, ground water, stream water, spring water under different land use 6)Study on paddy-to-river transfer of radionuclides through suspended sediments 7)Study on river-to-ocean transfer of radionuclides via suspended sediments 8)Confirmation of radionuclide deposition in ponds and reservoirs

  6. Atomic Bomb Health Benefits

    PubMed Central

    Luckey, T. D.

    2008-01-01

    Media reports of deaths and devastation produced by atomic bombs convinced people around the world that all ionizing radiation is harmful. This concentrated attention on fear of miniscule doses of radiation. Soon the linear no threshold (LNT) paradigm was converted into laws. Scientifically valid information about the health benefits from low dose irradiation was ignored. Here are studies which show increased health in Japanese survivors of atomic bombs. Parameters include decreased mutation, leukemia and solid tissue cancer mortality rates, and increased average lifespan. Each study exhibits a threshold that repudiates the LNT dogma. The average threshold for acute exposures to atomic bombs is about 100 cSv. Conclusions from these studies of atomic bomb survivors are: One burst of low dose irradiation elicits a lifetime of improved health.Improved health from low dose irradiation negates the LNT paradigm.Effective triage should include radiation hormesis for survivor treatment. PMID:19088902

  7. The Atomic Dating Game.

    ERIC Educational Resources Information Center

    Cummo, Evelyn; Matthews, Catherine E.

    2002-01-01

    Presents an activity designed to provide students with opportunities to practice drawing atomic models and discover the logical pairings of whole families on the periodic table. Follows the format of a television game show. (DDR)

  8. The Casimir atomic pendulum

    NASA Astrophysics Data System (ADS)

    Razmi, H.; Abdollahi, M.

    2008-11-01

    We want to introduce an atomic pendulum whose driving force (torque) is due to the quantum vacuum fluctuations. Applying the well-known Casimir-Polder effect to a special configuration (a combined structure of an atomic nanostring and a conducting plate), an atomic pendulum (Casimir atomic pendulum) is designed. Using practically acceptable data corresponding to the already known world of nanotechnology and based on reasonable/reliable numerical estimates, the period of oscillation for the pendulum is computed. This pendulum can be considered as both a new micro(nano)-electromechanical system and a new simple vacuum machine. Its design may be considered as a first step towards realizing the visualized vacuum (Casimir) clock!

  9. Atomic hydrogen rocket engine

    NASA Technical Reports Server (NTRS)

    Etters, R. D.; Flurchick, K.

    1981-01-01

    A rocket using atomic hydrogen propellant is discussed. An essential feature of the proposed engine is that the atomic hydrogen fuel is used as it is produced, thus eliminating the necessity of storage. The atomic hydrogen flows into a combustion chamber and recombines, producing high velocity molecular hydrogen which flows out an exhaust port. Standard thermodynamics, kinetic theory and wall recombination cross-sections are used to predict a thrust of approximately 1.4 N for a RF hydrogen flow rate of 4 x 10 to the 22nd/sec. Specific impulses are nominally from 1000 to 2000 sec. It is predicted that thrusts on the order of one Newton and specific impulses of up to 2200 sec are attainable with nominal RF discharge fluxes on the order of 10 to the 22nd atoms/sec; further refinements will probably not alter these predictions by more than a factor of two.

  10. Single-Atom Electrocatalysts.

    PubMed

    Zhu, Chengzhou; Fu, Shaofang; Shi, Qiurong; Du, Dan; Lin, Yuehe

    2017-11-06

    Recent years have witnessed a dramatic increase in the production of sustainable and renewable energy. However, the electrochemical performances of the various systems are limited, and there is an intensive search for highly efficient electrocatalysts by more rational control over the size, shape, composition, and structure. Of particular interest are the studies on single-atom catalysts (SACs), which have sparked new interests in electrocatalysis because of their high catalytic activity, stability, selectivity, and 100 % atom utilization. In this Review, we introduce innovative syntheses and characterization techniques for SACs, with a focus on their electrochemical applications in the oxygen reduction/evolution reaction, hydrogen evolution reaction, and hydrocarbon conversion reactions for fuel cells (electrooxidation of methanol, ethanol, and formic acid). The electrocatalytic performance is further considered at an atomic level and the underlying mechanisms are discussed. The ultimate goal is the tailoring of single atoms for electrochemical applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Atomic bomb health benefits.

    PubMed

    Luckey, T D

    2008-01-01

    Media reports of deaths and devastation produced by atomic bombs convinced people around the world that all ionizing radiation is harmful. This concentrated attention on fear of miniscule doses of radiation. Soon the linear no threshold (LNT) paradigm was converted into laws. Scientifically valid information about the health benefits from low dose irradiation was ignored. Here are studies which show increased health in Japanese survivors of atomic bombs. Parameters include decreased mutation, leukemia and solid tissue cancer mortality rates, and increased average lifespan. Each study exhibits a threshold that repudiates the LNT dogma. The average threshold for acute exposures to atomic bombs is about 100 cSv. Conclusions from these studies of atomic bomb survivors are: One burst of low dose irradiation elicits a lifetime of improved health.Improved health from low dose irradiation negates the LNT paradigm.Effective triage should include radiation hormesis for survivor treatment.

  12. 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).

  13. Metal atomization spray nozzle

    DOEpatents

    Huxford, Theodore J.

    1993-01-01

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal.

  14. Optical atomic magnetometer

    DOEpatents

    Budker, Dmitry; Higbie, James; Corsini, Eric P.

    2013-11-19

    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  15. Metal atomization spray nozzle

    DOEpatents

    Huxford, T.J.

    1993-11-16

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal. 6 figures.

  16. Hirshfeld atom refinement.

    PubMed

    Capelli, Silvia C; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-09-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  17. On the bosonic atoms

    NASA Astrophysics Data System (ADS)

    Amusia, M. Ya.; Chernysheva, L. V.

    2018-01-01

    We investigate ground state properties of atoms, in which substitute fermions - electrons by bosons, namely π --mesons. We perform some calculations in the frame of modified Hartree-Fock (HF) equation. The modification takes into account symmetry, instead of anti-symmetry of the pair identical bosons wave function. The modified HF approach thus enhances (doubles) the effect of self-action for the boson case. Therefore, we accordingly modify the HF equations by eliminating the self-action terms "by hand". The contribution of meson-meson and meson-nucleon non-Coulomb interaction is inessential at least for atoms with low and intermediate nuclear charge, which is our main subject. We found that the binding energy of pion negative ions A π - , pion atoms A π , and the number of extra bound pions ΔN π increases with the growth of nuclear charge Z. For e.g. Xe ΔN π = 4. As an example of a simple process with a pion atom, we consider photoionization that differs essentially from that for electron atoms. Namely, it is not monotonic decreasing from the threshold but has instead a prominent maximum above threshold. We study also elastic scattering of pions by pion atoms.

  18. Atomic mass compilation 2012

    SciTech Connect

    Pfeiffer, B., E-mail: bpfeiffe@uni-mainz.de; GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt; Venkataramaniah, K.

    2014-03-15

    Atomic mass reflects the total binding energy of all nucleons in an atomic nucleus. Compilations and evaluations of atomic masses and derived quantities, such as neutron or proton separation energies, are indispensable tools for research and applications. In the last decade, the field has evolved rapidly after the advent of new production and measuring techniques for stable and unstable nuclei resulting in substantial ameliorations concerning the body of data and their precision. Here, we present a compilation of atomic masses comprising the data from the evaluation of 2003 as well as the results of new measurements performed. The relevant literaturemore » in refereed journals and reports as far as available, was scanned for the period beginning 2003 up to and including April 2012. Overall, 5750 new data points have been collected. Recommended values for the relative atomic masses have been derived and a comparison with the 2003 Atomic Mass Evaluation has been performed. This work has been carried out in collaboration with and as a contribution to the European Nuclear Structure and Decay Data Network of Evaluations.« less

  19. Launch Vehicle Performance for Bipropellant Propulsion Using Atomic Propellants With Oxygen

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2000-01-01

    Atomic propellants for bipropellant launch vehicles using atomic boron, carbon, and hydrogen were analyzed. The gross liftoff weights (GLOW) and dry masses of the vehicles were estimated, and the 'best' design points for atomic propellants were identified. Engine performance was estimated for a wide range of oxidizer to fuel (O/F) ratios, atom loadings in the solid hydrogen particles, and amounts of helium carrier fluid. Rocket vehicle GLOW was minimized by operating at an O/F ratio of 1.0 to 3.0 for the atomic boron and carbon cases. For the atomic hydrogen cases, a minimum GLOW occurred when using the fuel as a monopropellant (O/F = 0.0). The atomic vehicle dry masses are also presented, and these data exhibit minimum values at the same or similar O/F ratios as those for the vehicle GLOW. A technology assessment of atomic propellants has shown that atomic boron and carbon rocket analyses are considered to be much more near term options than the atomic hydrogen rockets. The technology for storing atomic boron and carbon has shown significant progress, while atomic hydrogen is not able to be stored at the high densities needed for effective propulsion. The GLOW and dry mass data can be used to estimate the cost of future vehicles and their atomic propellant production facilities. The lower the propellant's mass, the lower the overall investment for the specially manufactured atomic propellants.

  20. 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

  1. Atom-atom inelastic collisions and three-body atomic recombination in weakly ionized argon plasmas

    NASA Technical Reports Server (NTRS)

    Braun, C. G.; Kunc, J. A.

    1989-01-01

    A stationary collisional-radiative model including both inelastic electron-atom and atom-atom collisions is used to examine nonequilibrium weakly ionized argon plasmas with atomic densities 10 to the 16th to 10 to the 20th/cu cm, temperatures below 6000 K, and with different degrees of radiation trapping. It is shown that three-body atomic recombination becomes important at high particle densities. Comparison is made between the present approach and Thomson's theory for atomic recombination.

  2. Association of Acute Radiation Syndrome and Rain after the Bombings in Atomic Bomb Survivors.

    PubMed

    Ozasa, K; Sakata, R; Cullings, H M; Grant, E J

    2016-06-01

    Acute radiation-induced symptoms reported in survivors after the atomic bombings in Hiroshima and Nagasaki have been suspected to be associated with rain that fell after the explosions, but this association has not been evaluated in an epidemiological study that considers the effects of the direct dose from the atomic bombs and other factors. The aim of this study was to evaluate this association using information from a fixed cohort, comprised of 93,741 members of the Life Span Study who were in the city at the time of the bombing. Information on acute symptoms and exposure to rain was collected in surveys conducted by interviewers, primarily in the 1950s. The proportion of survivors developing severe epilation was around 60% at levels of direct radiation doses of 3 Gy or higher and less than 0.2% at levels <0.005 Gy regardless of reported rain exposure status. The low prevalence of acute symptoms at low direct doses indicates that the reported fallout rain was not homogeneously radioactive at a level sufficient to cause a substantial probability of acute symptoms. We observed that the proportion of reported acute symptoms was slightly higher among those who reported rain exposure in some subgroups, however, suggestions that rain was the cause of these reported symptoms are not supported by analyses specific to the known areas of radioactive fallout. Misclassification of exposure and outcome, including symptoms due to other causes and recall bias, appears to be a more plausible explanation. However, the insufficient and retrospective nature of the available data limited our ability to quantify the attribution to those possible causes.

  3. Change-in-ratio

    USGS Publications Warehouse

    Udevitz, Mark S.; El-Shaarawi, Abdel H.; Piegorsch, Walter W.

    2002-01-01

    Change-in-ratio (CIR) methods are used to estimate parameters for ecological populations subject to differential removals from population subclasses. Subclasses can be defined according to criteria such as sex, age, or size of individuals. Removals are generally in the form of closely monitored sport or commercial harvests. Estimation is based on observed changes in subclass proportions caused by the removals.

  4. Gender Ratio in Dyslexia.

    ERIC Educational Resources Information Center

    Miles, T. R.; Haslum, M. N.; Wheeler, T. J.

    1998-01-01

    A study involving 11,804 British children (age 10) found that when specified criteria for dyslexia were used, 269 children qualified as dyslexic. These included 223 boys and 46 girls, for a ratio of 4.51 to 1. Difficulties in interpreting these data are discussed and a defense of the criteria is provided. (Author/CR)

  5. Radius Ratio Rule Rescue

    ERIC Educational Resources Information Center

    Michmerhuizen, Anna; Rose, Karine; Annankra, Wentiirim; Vander Griend, Douglas A.

    2017-01-01

    Making optimal pedagogical and predictive use of the radius ratio rule to distinguish between solid state structures that feature tetrahedral, octahedral and cubic holes requires several updated insights. A comparative analysis of the Born-Landé equation for lattice energy is developed to show that the rock salt structure is a suitable choice for…

  6. A Recipe for Ratio

    ERIC Educational Resources Information Center

    Moffett, Pamela

    2012-01-01

    Many learners still struggled to appreciate, and understand the difference between, the concepts of fractions and ratio. This is not just a UK phenomenon, which is demonstrated here by the use of a resource developed by the Wisconsin Centre for Education, in association with the Freudenthal Institute of the University of Utrecht, with a group of…

  7. Change-in-ratio

    USGS Publications Warehouse

    Udevitz, Mark S.

    2014-01-01

    Change-in-ratio (CIR) methods are used to estimate parameters for ecological populations subject to differential removals from population subclasses. Subclasses can be defined according to criteria such as sex, age, or size of individuals. Removals are generally in the form of closely monitored sport or commercial harvests. Estimation is based on observed changes in subclass proportions caused by the removals.

  8. Risk of Thyroid Nodules in Residents of Belarus Exposed to Chernobyl Fallout as Children and Adolescents.

    PubMed

    Cahoon, Elizabeth K; Nadyrov, Eldar A; Polyanskaya, Olga N; Yauseyenka, Vasilina V; Veyalkin, Ilya V; Yeudachkova, Tamara I; Maskvicheva, Tamara I; Minenko, Victor F; Liu, Wayne; Drozdovitch, Vladimir; Mabuchi, Kiyohiko; Little, Mark P; Zablotska, Lydia B; McConnell, Robert J; Hatch, Maureen; Peters, Kamau O; Rozhko, Alexander V; Brenner, Alina V

    2017-07-01

    Although radiation exposure is an important predictor of thyroid cancer on diagnosis of a thyroid nodule, the relationship between childhood radiation exposure and thyroid nodules has not been comprehensively evaluated. To examine the association between internal I-131 thyroid dose and thyroid nodules in young adults exposed during childhood. In this cross-sectional study, we screened residents of Belarus aged ≤18 years at the time of the Chernobyl nuclear accident for thyroid disease (median age, 21 years) with thyroid palpation, ultrasonography, blood/urine analysis, and medical follow-up when appropriate. Eligible participants (N = 11,421) had intact thyroid glands and doses based on direct individual thyroid activity measurements. Excess odds ratios per Gray (EOR/Gy, scaled at age 5 years at exposure) for any thyroid nodule and for nodules grouped by cytology/histology, diameter size, and singularity. Risk of any thyroid nodule increased significantly with I-131 dose and, for a given dose, with younger age at exposure. The EOR/Gy (95% confidence intervals) for neoplastic nodules (3.82; 0.87 to 15.52) was significantly higher than for nonneoplastic nodules (0.32; <0.03 to 0.70) and did not vary by size; whereas the EOR/Gy for nonneoplastic nodules did vary by size (P = 0.02) and was 1.55 (0.36 to 5.46) for nodules ≥10 mm and 0.02 (<-0.02 to 0.70) for nodules <10 mm. EORs/Gy for single and multiple nodules were comparable. Childhood exposure to internal I-131 is associated with increased risk of neoplastic thyroid nodules of any size and nonneoplastic nodules ≥10 mm.

  9. Atomic resolution holography.

    PubMed

    Hayashi, Kouichi

    2014-11-01

    Atomic resolution holography, such as X-ray fluorescence holography (XFH)[1] and photoelectron holography (PH), has the attention of researcher as an informative local structure analysis, because it provides three dimensional atomic images around specific elements within a range of a few nanometers. It can determine atomic arrangements around a specific element without any prior knowledge of structures. It is considered that the atomic resolution holographic is a third method of structural analysis at the atomic level after X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). As known by many researchers, XRD and XAFS are established methods that are widespread use in various fields. XRD and XAFS provide information on long-range translational periodicities and very local environments, respectively, whereas the atomic resolution holography gives 3D information on the local order and can visualize surrounding atoms with a large range of coordination shells. We call this feature "3D medium-range local structure observation".In addition to this feature, the atomic resolution holography is very sensitive to the displacement of atoms from their ideal positions, and one can obtain quantitative information about local lattice distortions by analyzing reconstructed atomic images[2] When dopants with different atomic radii from the matrix elements are present, the lattices around the dopants are distorted. However, using the conventional methods of structural analysis, one cannot determine the extent to which the local lattice distortions are preserved from the dopants. XFH is a good tool for solving this problem.Figure 1 shows a recent achievement on a relaxor ferroelectric of Pb(Mg1/3Nb2/3)O3 (PMN) using XFH. The structural studies of relaxor ferroelectrics have been carried out by X-ray or neutron diffractions, which suggested rhombohedral distortions of their lattices. However, their true pictures have not been obtained, yet. The Nb Kα holograms showed

  10. Atomic transient recorder.

    PubMed

    Kienberger, R; Goulielmakis, E; Uiberacker, M; Baltuska, A; Yakovlev, V; Bammer, F; Scrinzi, A; Westerwalbesloh, Th; Kleineberg, U; Heinzmann, U; Drescher, M; Krausz, F

    2004-02-26

    In Bohr's model of the hydrogen atom, the electron takes about 150 attoseconds (1 as = 10(-18) s) to orbit around the proton, defining the characteristic timescale for dynamics in the electronic shell of atoms. Recording atomic transients in real time requires excitation and probing on this scale. The recent observation of single sub-femtosecond (1 fs = 10(-15) s) extreme ultraviolet (XUV) light pulses has stimulated the extension of techniques of femtochemistry into the attosecond regime. Here we demonstrate the generation and measurement of single 250-attosecond XUV pulses. We use these pulses to excite atoms, which in turn emit electrons. An intense, waveform-controlled, few cycle laser pulse obtains 'tomographic images' of the time-momentum distribution of the ejected electrons. Tomographic images of primary (photo)electrons yield accurate information of the duration and frequency sweep of the excitation pulse, whereas the same measurements on secondary (Auger) electrons will provide insight into the relaxation dynamics of the electronic shell following excitation. With the current approximately 750-nm laser probe and approximately 100-eV excitation, our transient recorder is capable of resolving atomic electron dynamics within the Bohr orbit time.

  11. Accelerator mass spectrometry measurement of 240Pu/239Pu isotope ratios in Novaya Zemlya and Kara Sea sediments.

    PubMed

    Oughton, Deborah H; Skipperud, Lindis; Fifield, L Keith; Cresswell, Richard G; Salbu, Brit; Day, Philip

    2004-01-01

    Generally low levels of plutonium in environmental samples, often combined with limited sample sizes, necessitate reliable low-level techniques for determination of Pu isotopes. Accelerator mass spectrometry (AMS) has proved to be a powerful method for measuring low-level Pu activity concentrations and Pu isotope ratios. Based on procedural blanks, detection limits for AMS were below 1 fg Pu (equivalent to ca. 2 microBq 139Pu), which can compete with both TIMS, high sensitivity ICP-MS, and certainly alpha-spectrometry, while showing less interference, memory and matrix effects as compared to routine ICP-MS techniques. In addition to low detection limits, the technique offers the advantage of giving information on Pu isotope ratios. Measurements of sediments collected from dumping sites at Novaya Zemlya showed deviation from global fallout 240Pu/239Pu ratios.

  12. Morphological abnormalities in gall-forming aphids in a radiation-contaminated area near Fukushima Daiichi: selective impact of fallout?

    PubMed Central

    Akimoto, Shin-ichi

    2014-01-01

    To evaluate the impact of fallout from the Fukushima Daiichi Nuclear Power Plant accident on organisms, this study compared the morphology and viability of gall-forming aphids between the Fukushima population and control populations from noncontaminated areas. This study, in particular, focused on the morphology of first-instar gall formers derived from the first sexual reproduction after the accident. Of 164 first instars from Tetraneura sorini galls collected 32 km from Fukushima Daiichi in spring 2012, 13.2% exhibited morphological abnormalities, including four conspicuously malformed individuals (2.4%). In contrast, in seven control areas, first instars with abnormal morphology accounted for 0.0–5.1% (on average, 3.8%). The proportions of abnormalities and mortality were significantly higher in Fukushima than in the control areas. Similarly, of 134 first instars from T. nigriabdominalis galls, 5.9% exhibited morphological abnormalities, with one highly malformed individual. However, of 543 second-generation larvae produced in T. sorini galls, only 0.37% had abnormalities, suggesting that abnormalities found in the first generation were not inherited by the next generation. Although investigation is limited to one study site, this result suggests that radioactive contamination had deleterious effects on embryogenesis in eggs deposited on the bark surface, but a negligible influence on the second generation produced in closed galls. Furthermore, analysis of both species samples collected in spring 2013 indicated that the viability and healthiness of the aphids were significantly improved compared to those in the 2012 samples. Thus, the results of this study suggest the possibility that a reduced level of radiation and/or selection for radiation tolerance may have led to the improved viability and healthiness of the Fukushima population. PMID:24634721

  13. Combining multiple fallout radionuclides (137Cs, 7Be, 210Pbxs) improves our understanding of sediment source dynamics in tropical rivers

    NASA Astrophysics Data System (ADS)

    Evrard, O.; Laceby, J. P.; Huon, S.; Lefèvre, I.; Sengtaheuanghoung, O.; Ribolzi, O.

    2015-12-01

    Soil erosion has accelerated as a result of land use change, increasing the sediment supply to rivers worldwide. A thorough knowledge of sediment dynamics is required to design efficient management measures to control erosion and reduce sediment delivery from catchments. Fallout radionuclides are often used separately to provide spatial (137Cs) or temporal (7Be, 210Pbxs) information on sediment sources. In this study, we examine their combined application to simultaneously model spatial and temporal sediment source dynamics. To this end, potential sediment sources (n=84) and suspended sediment (n=16) were collected at two stations in a 12 km² catchment in Northern Laos during the first flood of the 2014 wet season. Part of the source material was directly sampled in ephemeral flow occurring on hillslopes to avoid the grain size selectivity problems that may occur during erosion and river transport processes. A distribution modelling approach quantified the relative contributions of recently eroded surface (labelled with both 7Be and 137Cs), recently eroded subsurface (depleted in both 7Be and 137Cs), re-suspended surface (depleted in 7Be and labelled with 137Cs) and re-suspended subsurface sources (enriched in 7Be and depleted in 137Cs). At an upstream sampling location, surface sources contributed the majority of sediment (55%) whereas subsurface sources dominated the supply of sediment downstream (74%). Importantly, re-suspended subsurface sources, labelled with 7Be, were a significant sediment source at the catchment outlet (60%). This approach demonstrates the utility of combining multiple radionuclides when investigating spatial and temporal sediment source dynamics in tropical catchments. In the future, sampling of source material in ephemeral flows occurring on hillslopes should be encouraged. Furthermore, the proposed approach should be tested in larger catchments to guide the implementation of efficient erosion control measures.

  14. Prenatal exposure to Chernobyl fallout in Norway: neurological and developmental outcomes in a 25-year follow-up.

    PubMed

    Lie, Rolv Terje; Moster, Dag; Strand, Per; Wilcox, Allen James

    2017-12-01

    Ionizing radiation at high doses early in life may cause neurodevelopmental problems. Possible effects of lower doses are, however, controversial. We use carefully collected exposure data for Norway following the Chernobyl accident in April 1986 combined with population-based registries to assess long-term effects of fetal exposure on neurodevelopmental outcomes. Radiation doses were estimated for each Norwegian municipality for each calendar month from May 1986 to April 1989. We established a cohort of all Norwegian pregnancies during the three-year period of radiation measurement and compared them with appropriate unexposed groups. All cohorts were followed into adulthood. Risks of cerebral palsy, mental retardation, schizophrenia, epilepsy, vision or hearing problems, school dropout, and low income were estimated. We also conducted an analysis of mathematics and language grades using siblings born after the exposure period as comparison. There was little evidence of associations between radiation exposure and cerebral palsy, mental retardation, schizophrenia, epilepsy, or hearing or vision problems associated with radiation exposure. (p-values for trend with exposure dose were 0.27, 0.14, 0.83, 0.35 and 0.42.) Slightly more of the exposed failed to complete high school (p = 0.05), but there was no increase in the proportion with low income (p = 0.38). The natural advantage of older siblings over younger siblings in mathematics grades was diminished with exposure of older siblings (p = 0.003), but there was no association of exposure with Norwegian language grades (p = 0.37). There is scant evidence that the low-dose fallout from Chernobyl in Norway increased the risk for serious neurodevelopmental problems. We cannot exclude the possibility of lower mathematics grades with exposure, similar to a report from Sweden.

  15. Ten years of elemental atmospheric metal fallout and Pb isotopic composition monitoring using lichens in north-eastern France

    NASA Astrophysics Data System (ADS)

    Cloquet, Christophe; Estrade, Nicolas

    2016-04-01

    We report on the chemical and Pb isotopic compositions of epiphytic lichens collected from small tree branches in the urban area of the city of Metz (NE France). Lichens were collected in five different years between 2001 and 2009. The data are first compared year to year in order to document any temporal changes and trends in metal atmospheric fallout. The area studied was then subdivided into different zones on the basis of land-use (urban, suburban, rural and industrial) in order to determine potential spatial gradients. The median concentrations and enrichment factors (EF, normalized to Al) of Pb and other metals (Cu, Zn, Cd, Ni, Cr, Hg, Fe) in lichens from the urban, suburban, and rural zones show no systematic variation between 2001 and 2008. However, the metal EFs show spatial variation and are generally highest in the urban area and lowest in the rural area. Lichens within the industrial zone (collected in 2009), which is dominated by steel industries, are richest in Al, Fe, Cr, Pb, and Zn. Although the Al concentration is high in these lichens, the EFs for the cited metals are several times higher than those measured in lichens from the other three zones. No significant differences were noted for Hg, Cd, Cu and or Ni. Lead isotopic compositions measured in lichens may be highly variable from year to year and from zone to zone. The variation is primarily interpreted to result from mixing between: (i) Pb added to gasoline (and recycled through re-emission of road dust in the atmosphere); (ii) regional industrial Pb from long-range transportation and/or mixed with urban Pb; and (iii) local industrial Pb. The median isotopic compositions of individual zones are distinct, suggesting variable mixing of these three sources. The annual variations show that 2001 was most affected by gasoline Pb, whereas 2003 and 2006 were more affected by the local steel industry.

  16. Ten years of elemental atmospheric metal fallout and Pb isotopic composition monitoring using lichens in northeastern France

    NASA Astrophysics Data System (ADS)

    Cloquet, Christophe; Estrade, Nicolas; Carignan, Jean

    2015-09-01

    We report on the chemical and Pb isotopic compositions of epiphytic lichens collected from small tree branches in the urban area of the city of Metz (NE France). Lichens were collected in five different years between 2001 and 2009. The data are first compared year to year in order to document any temporal change and trend in metal atmospheric fallout. The area studied was then subdivided into different zones on the basis of land use (urban, suburban, rural and industrial) in order to determine potential spatial gradients. The median concentrations and enrichment factors (EF, normalized to Al) of Pb and other metals (Cu, Zn, Cd, Ni, Cr, Hg, Fe) in lichens from the urban, suburban, and rural zones show no systematic variation between 2001 and 2008. However, the metal EFs show spatial variation and are generally highest in the urban area and lowest in the rural area. Lichens within the industrial zone (collected in 2009), which is dominated by steel industries, are richest in Al, Fe, Cr, Pb, and Zn. Although the Al concentration is high in these lichens, the EFs for the cited metals are several times higher than those measured in lichens from the other three zones. No significant differences were noted for Hg, Cd, Cu and or Ni. Pb isotopic compositions measured in lichens may be highly variable from year to year and from zone to zone. The variation is primarily interpreted to result from mixing between: (i) Pb added to gasoline (and recycled through re-emission of road dust in the atmosphere); (ii) regional industrial Pb from long-range transportation and/or mixed with urban Pb; and (iii) local industrial Pb. The median isotopic compositions of individual zones are distinct, suggesting variable mixing of these three sources. The annual variations show that 2001 was most affected by gasoline Pb, whereas 2003 and 2006 were more affected by the local steel industry.

  17. Sediment transfer in coastal catchments exposed to typhoons: lessons learnt from catchments contaminated with Fukushima radioactive fallout

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Laceby, J. Patrick; Onda, Yuichi; Lefèvre, Irène

    2016-04-01

    Several coastal catchments located in Northeastern Japan received significant radioactive fallout following the Fukushima nuclear accident in March 2011, with initial 137Cs activities exceeding 100 kBq m-2. Although radiocesium poses a considerable health risk for local populations, it also provides a relatively straightforward tracer to investigate sediment transfers in catchments exposed to spring floods and heavy typhoons in late summer and early fall. This study focused on two catchments (the Niida and Mano Rivers) covering a surface area of 450 km² that drain the main radioactive plume. A database of radiocesium activities measured in potential source samples (n=260) was used to model radiocesium dilution in 342 sediment deposit samples collected at 38 locations during 9 different sampling campaigns conducted every 6 months from Nov. 2011 to Nov. 2015. The dilution of the initial radiocesium contamination in sediment was individually calculated for each of the 342 samples using a distribution model. Results show that the proportion of heavily contaminated sediment increased from 27% to 39% after the occurrence of typhoons in 2013 (with rainfall amount exceeding 100 mm in 48 hours) and from 29% to 45% after the 2015 spring floods, illustrating the occurrence of soil erosion and resuspension of contaminated material stored in the river channel. In contrast, the occurrence of a very strong typhoon in September 2015 (up to 450 mm in 48h) led to the dilution and the flush of the contamination to the Pacific Ocean, with the proportion of heavily contaminated material decreasing from 45 to 21%. This case study in catchments impacted by the Fukushima accident illustrates their high reactivity to both human activities and rainfall. These results will improve our understanding of sediment transfers in similar coastal mountainous environments frequently exposed to heavy rainfall.

  18. Sources and ages of fine-grained sediment to streams using fallout radionuclides in the Midwestern United States

    USGS Publications Warehouse

    Gellis, Allen; Fuller, Christopher C.; Van Metre, Peter C.

    2017-01-01

    Fallout radionuclides, 7Be and 210Pbex, sampled in bed sediment for 99 watersheds in the Midwestern region of the United States and in 15 samples of suspended sediment from 3 of these watersheds were used to partition upland from channel sources and to estimate the age or the time since the surface-derived portion of sediment was on the land surface (0–∼1 year). Channel sources dominate: 78 of the 99 bed material sites (79%) have >50% channel-derived sediment, and 9 of the 15 suspended-sediment samples (60%) have >50% channel-derived sediment. 7Be was detected in 82 bed sediment samples and all 15 suspended-sediment samples. The surface-derived portion of 54 of the 80 (68%) streams with detectable 7Be and 210Pbex were ≤ 100 days old and the surface-derived portion of all suspended-sediment samples were ≤ 100 days old, indicating that surface-derived fine-grained sediment moves rapidly though these systems. The concentrations of two hydrophobic pesticides–DDE and bifenthrin–are correlated with the proportion of surface-derived sediment, indicating a link between geomorphic processes and particle-associated contaminants in streams. Urban areas had the highest pesticide concentrations and the largest percentage of surface-derived sediment. Although the percentage of surface-derived sediment is less than channel sources at most of the study sites, the relatively young age of the surface-derived sediment might indicate that management actions to reduce sediment contamination where the land surface is an important source could have noticeable effects.

  19. Distal Enhanced Sedimentation From Volcanic Plumes: Insights From the Secondary Mass Maxima in the 1992 Mount Spurr Fallout Deposits

    NASA Astrophysics Data System (ADS)

    Eychenne, Julia; Rust, Alison C.; Cashman, Katharine V.; Wobrock, Wolfram

    2017-10-01

    Some tephra fallout deposits show an increase of mass and thickness at distances from the source >100 km (areas of secondary mass maximum, ASMM) which demonstrates distal enhanced sedimentation from volcanic plumes. We explore development of the ASMMs during the 1992 August and September Mount Spurr eruptions, USA, by combining field data on the spatial distribution of mass and grain size with (1) simulations of individual particle settling through a homogeneous and horizontally stratified atmosphere and (2) mesoscale models of the three-dimensional wind field that include the effect of the underlying topography. The crosswind and downwind variations of deposit characteristics indicate that the increase of sedimentation at the ASMMs is not formed solely because of preferential settling of small ash particles (<125 μm), as commonly assumed in aggregation models. Instead, ASMM grain sizes correspond to the fine modes of the bimodal total grain size distributions. There also appears to be a link between the ASMM and the topography: the mass local minima occur across the windward flank of 2 km high mountain ranges, while the ASMMs spread on the leeward flank. Mesoscale models of the three-dimensional wind field show vertical oscillations in the wind over mountainous regions which may enhance mechanisms of en masse sedimentation (aggregation, hydrometeor formation, and particle boundary layers), as well as strong spatial variations of the horizontal wind field in the lower troposphere. Our study demonstrates the importance of using grain size, as well as mass, data to constrain the complex processes responsible for particle sedimentation from volcanic plumes.

  20. Large momentum transfer atomic interferometric gyroscope

    NASA Astrophysics Data System (ADS)

    Compton, Robert; Dorr, Joshua; Nelson, Karl; Parker, Richard; Estey, Brian; Müller, Holger

    2017-04-01

    Atom interferometry holds out significant promise as the basis for compact, low cost, high performance inertial sensing. Some light pulse atom interferometers are based on an atomic beam-splitter in which the interferometer paths separate at the velocity imparted by a two-photon (Raman) recoil event, resulting in narrow path separation and a corresponding high aspect ratio between the length and width of the interferometer. In contrast, proposals for large momentum transfer (LMT) offer paths to larger separation between interferometer arms, and aspect ratios approaching 1. Here, we demonstrate an LMT gyroscope based on a combination of Bragg and Bloch atomic transitions adding up to a total of 8 photons of momentum transfer. We discuss prospects for scalability to larger photon numbers where angular random walk (ARW) can be better than navigation-grade. This research was developed with funding from DARPA. The views, opinions, and/or findings contained herein are those of the presenters and should not be interpreted as representing the official views or policies of the DoD or the US Government.

  1. Double photoionization of atoms

    NASA Astrophysics Data System (ADS)

    Wiedenhoeft, Marco

    2003-10-01

    Double photoionization studies of atoms and molecules are new state-of-the-art studies providing a deeper knowledge of multi-electron excitations. This type of work advances the understanding of many-body problems. Double photoionization of atoms is of great interest to learn about electron-electron correlation and relaxation effects in atoms and molecules. In order to study double photoionization processes, a new electron-electron coincidence apparatus was built to carry out the measurements. I will present the apparatus I built as well as the results of the measurement of the triply-differential-cross-section (TDCS) for the predicted interference and Post-Collision-Interaction (PCI) effects in the Xenon N5O2,3 O2,3 Auger decay after 4d5/2 photoionization. Furthermore I present measurements for direct double photoionization of Helium at various photon energies.

  2. Atomic and molecular supernovae

    SciTech Connect

    Liu, W.

    1997-12-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra leadmore » to strong constraints on the supernova explosion models.« less

  3. Multi-ratio transmission

    SciTech Connect

    Polak, J.C.

    1987-07-14

    A preselected multi-ratio power transmission is described comprising: input means for transmitting drive forces; output means; first, second and third friction clutch means each selectively engageable with the input means for accepting drive forces. First input gear means drivingly connects with the first friction clutch means; second input gear means drivingly connects with the second friction clutch means; third input gear means drivingly connects with the third clutch means; first output gear means drivingly connects with the first input gear means; second output gear means drivingly connects with the first and second input gear means; third output means drivingly connects between the third input gear means and the output means; and one double-acting synchronizer clutch for selectively engaging the first output gear means with the output means and alternately the second output gear means with the output means. The first friction clutch means and the one double-acting synchronizer clutch cooperates during engagement to establish two forward drive ratios between the input and output means. The second friction clutch means and the one double-acting synchronizer clutch cooperates during engagement to establish two other forward drive ratios between the input and output means. The third friction clutch means is engageable to provide another forward drive ratio between the input means and the output means; and the one double-acting synchronizer clutch is relieved of transmitting drive forces during the engagement of the third friction clutch means and being manipulable for alternate connection with either the first output gear or the second output gear while the third friction clutch means is engaged.

  4. Iowa Powder Atomization Technologies

    ScienceCinema

    None

    2017-12-09

    The same atomization effect seen in a fuel injector is being applied to titanium metal resulting in fine titanium powders that are less than half the width of a human hair. Titanium melts above 3,000°F and is highly corrosive therefore requiring specialized containers. The liquid titanium is poured through an Ames Laboratory - USDOE patented tube which is intended to increase the energy efficiency of the atomization process, which has the ability to dramatically decrease the cost of fine titanium powders. This novel process could open markets for green manufacturing of titanium components from jet engines to biomedical implants.

  5. Atomization and Mixing Study

    NASA Technical Reports Server (NTRS)

    Ferrenberg, A.; Hunt, K.; Duesberg, J.

    1985-01-01

    The primary objective was the obtainment of atomization and mixing performance data for a variety of typical liquid oxygen/hydrocarbon injector element designs. Such data are required to establish injector design criteria and to provide critical inputs to liquid rocket engine combustor performance and stability analysis, and computational codes and methods. Deficiencies and problems with the atomization test equipment were identified, and action initiated to resolve them. Test results of the gas/liquid mixing tests indicated that an assessment of test methods was required. A series of 71 liquid/liquid tests were performed.

  6. Korean atomic bomb victims.

    PubMed

    Sasamoto, Yukuo

    2009-01-01

    After colonizing Korea, Japan invaded China, and subsequently initiated the Pacific War against the United States, Britain, and their allies. Towards the end of the war, U.S. warplanes dropped atomic bombs on Hiroshima and Nagasaki, which resulted in a large number of Koreans who lived in Hiroshima and Nagasaki suffering from the effects of the bombs. The objective of this paper is to examine the history of Korea atomic bomb victims who were caught in between the U.S., Japan, the Republic of Korea (South Korea) and the Democratic People's Republic of Korea (North Korea).

  7. Hirshfeld atom refinement

    PubMed Central

    Capelli, Silvia C.; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-01-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly–l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree–Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints – even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu’s), all other structural parameters agree within less than 2 csu’s. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å2 as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements – an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å. PMID:25295177

  8. Atomic Force Microscope

    SciTech Connect

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  9. Computer Modeling Of Atomization

    NASA Technical Reports Server (NTRS)

    Giridharan, M.; Ibrahim, E.; Przekwas, A.; Cheuch, S.; Krishnan, A.; Yang, H.; Lee, J.

    1994-01-01

    Improved mathematical models based on fundamental principles of conservation of mass, energy, and momentum developed for use in computer simulation of atomization of jets of liquid fuel in rocket engines. Models also used to study atomization in terrestrial applications; prove especially useful in designing improved industrial sprays - humidifier water sprays, chemical process sprays, and sprays of molten metal. Because present improved mathematical models based on first principles, they are minimally dependent on empirical correlations and better able to represent hot-flow conditions that prevail in rocket engines and are too severe to be accessible for detailed experimentation.

  10. Covalent bond orders and atomic anisotropies from iterated stockholder atoms.

    PubMed

    Wheatley, Richard J; Gopal, Angelica A

    2012-02-14

    Iterated stockholder atoms are produced by dividing molecular electron densities into sums of overlapping, near-spherical atomic densities. It is shown that there exists a good correlation between the overlap of the densities of two atoms and the order of the covalent bond between the atoms (as given by simple valence rules). Furthermore, iterated stockholder atoms minimise a functional of the charge density, and this functional can be expressed as a sum of atomic contributions, which are related to the deviation of the atomic densities from spherical symmetry. Since iterated stockholder atoms can be obtained uniquely from the electron density, this work gives an orbital-free method for predicting bond orders and atomic anisotropies from experimental or theoretical charge density data.

  11. Spatially resolved photoionization of ultracold atoms on an atom chip

    SciTech Connect

    Kraft, S.; Guenther, A.; Fortagh, J.; Zimmermann, C.

    2007-06-15

    We report on photoionization of ultracold magnetically trapped Rb atoms on an atom chip. The atoms are trapped at 5 {mu}K in a strongly anisotropic trap. Through a hole in the chip with a diameter of 150 {mu}m, two laser beams are focused onto a fraction of the atomic cloud. A first laser beam with a wavelength of 778 nm excites the atoms via a two-photon transition to the 5D level. With a fiber laser at 1080 nm the excited atoms are photoionized. Ionization leads to depletion of the atomic density distribution observed by absorption imaging. The resonant ionization spectrum is reported. The setup used in this experiment is suitable not only to investigate mixtures of Bose-Einstein condensates and ions but also for single-atom detection on an atom chip.

  12. Re-suspension of the radioactive fallout after the Fukushima accident: risk of internal dose during the first week and the first two months

    NASA Astrophysics Data System (ADS)

    Yamauchi, M.; Takeda, M.; Makino, M.; Owada, T.

    2012-04-01

    The nuclear accident at the Fukushima Dai-ichi Nuclear Power Plant in March 2011 contaminated an area of more than 100 km in diameter by radioactive material with amount of about 10-20% of that by the Chernobyl accident. According to the Chernobyl experience, a part of fallout radionuclide is expected to be re-suspended by wind, causing possible risk of internal dose. However, this re-suspension process and its amounts have not been studied very much due to the difficulty of direct measurement of low-density dusts. To estimate forms and periods of the re-suspension of the radioactive fallout, we used both the radiation dose rate data and vertical (downward) component of the DC electric field near the ground, or potential gradient (PG) at Kakioka, 150 km away from the accident site. The data indicates: (1) During 14-15 March, the radioactive dust is most likely suspended in the air near the ground. (2) During 2-7 UT on 16 March, the radioactive dust is most likely blown up from the surface by the strong wind from the non-contaminated area. (3) During 16-20 March, the radioactive dust most likely stayed re-suspended. (4) After the wet contamination on 20 March until late April, the radioactive fallout on the ground are re-suspended during daytime by daily convection due to sunshine, and transported to downwind direction. (5) At more than 30 km distance from the accident site, the re-suspension most likely ceased by the end of April. However, no data is available within 20 km distance from the accident site. Yamauchi, et al. (2012): Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement, Ann. Geophys., 30, 49-56, doi:10.5194/angeo-30-49-2012. Yamauchi (2012): Secondary wind transport of radioactive materials after the Fukushima accident, Earth Planet Space, accepted for publication.

  13. Bonds Between Atoms.

    ERIC Educational Resources Information Center

    Holden, Alan

    The field of inquiry into how atoms are bonded together to form molecules and solids crosses the borderlines between physics and chemistry encompassing methods characteristic of both sciences. At one extreme, the inquiry is pursued with care and rigor into the simplest cases; at the other extreme, suggestions derived from the more careful inquiry…

  14. FAC: Flexible Atomic Code

    NASA Astrophysics Data System (ADS)

    Gu, Ming Feng

    2018-02-01

    FAC calculates various atomic radiative and collisional processes, including radiative transition rates, collisional excitation and ionization by electron impact, energy levels, photoionization, and autoionization, and their inverse processes radiative recombination and dielectronic capture. The package also includes a collisional radiative model to construct synthetic spectra for plasmas under different physical conditions.

  15. Atoms in Astronomy.

    ERIC Educational Resources Information Center

    Blanchard, Paul A.

    This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. A Basic Topics section discusses atomic structure, emphasizing states of matter at high temperature and spectroscopic analysis of light from the stars. A section…

  16. Atomic collisions, inelastic indeed

    NASA Astrophysics Data System (ADS)

    Bercegol, Herve; Ferrando, Gwenael; Lehoucq, Roland

    At the turn of the twentieth century, a hot controversy raged about the ability of Boltzmann's framework to take care of irreversibility. The so-called Loschmidt's paradox progressively faded with time during the last hundred years, due to the predictive efficiency of statistical mechanics. However, one detail at the origin of the controversy - the elasticity of atomic collisions - was not completely challenged. A semi-classical treatment of two atoms interacting with the vacuum zero-point field permits to predict a friction force acting against the rotation of the pair of atoms. By its form and its level, the calculated torque is a candidate as a physical cause for diffusion of energy and angular momentum, and consequently for entropy growth. It opens the way to a revision of the standard vision of irreversibility. This presentation will focus on two points. First we will discuss the recent result in a broader context of electromagnetic interactions during microscopic collisions. The predicted friction phenomenon can be compared to and distinguished from Collision-Induced Emission and other types of inelastic collisions. Second we will investigate the consequences of the friction torque on calculated trajectories of colliding atoms, quantifying the generation of dimers linked by dispersion forces.

  17. Atomism, Pragmatism, Holism.

    ERIC Educational Resources Information Center

    Miller, John P.

    1986-01-01

    Examines three world views influencing curriculum development--atomism (underpinning competency-based education), pragmatism (promoting inquiry-based approaches), amd holism (associated with confluent or Waldorf education). Holism embodies the perennial philosophy and attempts to integrate cognitive, affective, and transpersonal dimensions,…

  18. Observational Evidence for Atoms.

    ERIC Educational Resources Information Center

    Jones, Edwin R., Jr.; Childers, Richard L.

    1984-01-01

    Discusses the development of the concept of atomicity and some of the many which can be used to establish its validity. Chemical evidence, evidence from crystals, Faraday's law of electrolysis, and Avogadro's number are among the areas which show how the concept originally developed from a purely philosophical idea. (JN)

  19. Atomically Traceable Nanostructure Fabrication

    PubMed Central

    Ballard, Josh B.; Dick, Don D.; McDonnell, Stephen J.; Bischof, Maia; Fu, Joseph; Owen, James H. G.; Owen, William R.; Alexander, Justin D.; Jaeger, David L.; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J.; Wallace, Robert M.; Reidy, Richard; Silver, Richard M.; Randall, John N.; Von Ehr, James

    2015-01-01

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure. PMID:26274555

  20. Advances in atomic fountains

    NASA Astrophysics Data System (ADS)

    Bize, S.; Laurent, P.; Abgrall, M.; Marion, H.; Maksimovic, I.; Cacciapuoti, L.; Grünert, J.; Vian, C.; Pereira dos Santos, F.; Rosenbusch, P.; Lemonde, P.; Santarelli, G.; Wolf, P.; Clairon, A.; Luiten, A.; Tobar, M.; Salomon, C.

    2004-10-01

    This article describes the work performed at BNM-SYRTE (Observatoire de Paris) in the past few years, toward the improvement and the use of microwave frequency standards using laser-cooled atoms. First, recent improvements of the 133Cs and 87Rb atomic fountains are described. An important advance is the achievement of a fractional frequency instability of 1.6×10τ where τ is the measurement time in seconds, thanks to the routine use of a cryogenic sapphire oscillator as an ultra-stable local frequency reference. The second advance is a powerful method to control the frequency shift due to cold collisions. These two advances lead to a fractional frequency in stability of 2×10 at 50 000 s between two independent primary standards. In addition, these clocks realize the SI second with an accuracy of 7×10, one order of magnitude below that of uncooled devices. Tests of fundamental physical laws constitute an important field of application for highly accurate atomic clocks. In a second part, we describe tests of possible variations of fundamental constants using 87Rb and 133Cs fountains. The third part is an update on the cold atom space clock PHARAO developed in collaboration with CNES. This clock is one of the main instruments of the ACES/ESA mission which will fly on board the International Space Station in 2007-2008, enabling a new generation of relativity tests. To cite this article: S. Bize et al., C. R. Physique 5 (2004).

  1. Quantum Confined Atoms

    NASA Astrophysics Data System (ADS)

    Bhargava, Rameshwar

    2001-03-01

    When the size of Tb3+ doped Y2O3 nanoparticles is decreased from about 10 nm to 3 nm, the luminescent efficiency of Tb3+ green-emission (f-f transition) is increased by an order of magnitude1. This enhancement of oscillator strength is interpreted due to modulation of excited-states of the Tb3+ ion, brought about by the confinement-boundary of the Y2O3 nanocrystal2. This high efficiency of 'caged' single Tb3+ or Eu3+ ion in Y2O3 has led to the first observation of an atomic blinking3. The Quantum Confined Atoms (QCA) provide a novel way to modulate the luminescent properties of a single activator atom via quantum confinement of higher excited states. This QCA-effect occurs when the size of the host is about 5 to 10 times the size of the radius of the excited-state atom. This discovery is expected to impact many applications in the area of nanotechnology. 1. R.N Bhargava, V. Chhabra, B. Kulkarni and J.V. Veliadis Phys. stat. sol. (b) 210, 621 (1998) 2. R.N. Bhargava Jour. of Crystal Growth 214, 926 (2000) 3. M. Barnes, A. Mehta, T. Thundant, R.N. Bhargava, V. Chhabra, B .Kulkarni Jour. Chem. Phys. B 104, 6099 (2000)

  2. Navigation with Atom Interferometers

    DTIC Science & Technology

    2017-03-20

    first (positive and negative) magnetic Raman transitions. Figure 4: Measured Spectrum of resonances useful for the atom gyroscope/accelerometer...gyroscope based on laser- cooled rubidium,” European Journal of Physics D, vol.53, no. 3, pp. 273-281, 2009. 12. Lenef, A., Hammond, T. D., Smith, E. T

  3. Precisely detecting atomic position of atomic intensity images.

    PubMed

    Wang, Zhijun; Guo, Yaolin; Tang, Sai; Li, Junjie; Wang, Jincheng; Zhou, Yaohe

    2015-03-01

    We proposed a quantitative method to detect atomic position in atomic intensity images from experiments such as high-resolution transmission electron microscopy, atomic force microscopy, and simulation such as phase field crystal modeling. The evaluation of detection accuracy proves the excellent performance of the method. This method provides a chance to precisely determine atomic interactions based on the detected atomic positions from the atomic intensity image, and hence to investigate the related physical, chemical and electrical properties. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Standardized mortality ratios.

    PubMed

    Taylor, Paul

    2013-12-01

    Mortality rates are increasingly used to compare the performance of hospitals and of units within hospitals. Different approaches have been taken to develop 'standardized' measures which adjust for the 'expected' mortality based on key characteristics of the population being treated. This article discusses the original motivation for looking at hospitals in this way in the UK, describes two recent incidents in which such measures were a critical element in decision making and reviews some of the strengths and weaknesses of the approaches. The current practice on the use of standardized mortality ratios is described.

  5. Trapped atoms along nanophotonic resonators

    NASA Astrophysics Data System (ADS)

    Fields, Brian; Kim, May; Chang, Tzu-Han; Hung, Chen-Lung

    2017-04-01

    Many-body systems subject to long-range interactions have remained a very challenging topic experimentally. Ultracold atoms trapped in extreme proximity to the surface of nanophotonic structures provides a dynamic system combining the strong atom-atom interactions mediated by guided mode photons with the exquisite control implemented with trapped atom systems. The hybrid system promises pair-wise tunability of long-range interactions between atomic pseudo spins, allowing studies of quantum magnetism extending far beyond nearest neighbor interactions. In this talk, we will discuss our current status developing high quality nanophotonic ring resonators, engineered on CMOS compatible optical chips with integrated nanostructures that, in combination with a side illuminating beam, can realize stable atom traps approximately 100nm above the surface. We will report on our progress towards loading arrays of cold atoms near the surface of these structures and studying atom-atom interaction mediated by photons with high cooperativity.

  6. HPAM: Hirshfeld Partitioned Atomic Multipoles

    PubMed Central

    Elking, Dennis M.; Perera, Lalith; Pedersen, Lee G.

    2011-01-01

    An implementation of the Hirshfeld (HD) and Hirshfeld-Iterated (HD-I) atomic charge density partitioning schemes is described. Atomic charges and atomic multipoles are calculated from the HD and HD-I atomic charge densities for arbitrary atomic multipole rank lmax on molecules of arbitrary shape and size. The HD and HD-I atomic charges/multipoles are tested by comparing molecular multipole moments and the electrostatic potential (ESP) surrounding a molecule with their reference ab initio values. In general, the HD-I atomic charges/multipoles are found to better reproduce ab initio electrostatic properties over HD atomic charges/multipoles. A systematic increase in precision for reproducing ab initio electrostatic properties is demonstrated by increasing the atomic multipole rank from lmax = 0 (atomic charges) to lmax = 4 (atomic hexadecapoles). Both HD and HD-I atomic multipoles up to rank lmax are shown to exactly reproduce ab initio molecular multipole moments of rank L for L ≤ lmax. In addition, molecular dipole moments calculated by HD, HD-I, and ChelpG atomic charges only (lmax = 0) are compared with reference ab initio values. Significant errors in reproducing ab initio molecular dipole moments are found if only HD or HD-I atomic charges used. PMID:22140274

  7. HPAM: Hirshfeld Partitioned Atomic Multipoles.

    PubMed

    Elking, Dennis M; Perera, Lalith; Pedersen, Lee G

    2012-02-01

    An implementation of the Hirshfeld (HD) and Hirshfeld-Iterated (HD-I) atomic charge density partitioning schemes is described. Atomic charges and atomic multipoles are calculated from the HD and HD-I atomic charge densities for arbitrary atomic multipole rank l(max) on molecules of arbitrary shape and size. The HD and HD-I atomic charges/multipoles are tested by comparing molecular multipole moments and the electrostatic potential (ESP) surrounding a molecule with their reference ab initio values. In general, the HD-I atomic charges/multipoles are found to better reproduce ab initio electrostatic properties over HD atomic charges/multipoles. A systematic increase in precision for reproducing ab initio electrostatic properties is demonstrated by increasing the atomic multipole rank from l(max) = 0 (atomic charges) to l(max) = 4 (atomic hexadecapoles). Both HD and HD-I atomic multipoles up to rank l(max) are shown to exactly reproduce ab initio molecular multipole moments of rank L for L ≤ l(max). In addition, molecular dipole moments calculated by HD, HD-I, and ChelpG atomic charges only (l(max) = 0) are compared with reference ab initio values. Significant errors in reproducing ab initio molecular dipole moments are found if only HD or HD-I atomic charges used.

  8. Role of atoms in atomic gravitational-wave detectors

    NASA Astrophysics Data System (ADS)

    Norcia, Matthew A.; Cline, Julia R. K.; Thompson, James K.

    2017-10-01

    Recently, it has been proposed that space-based atomic sensors may be used to detect gravitational waves. These proposals describe the sensors either as clocks or as atom interferometers. Here, we seek to explore the fundamental similarities and differences between the two types of proposals. We present a framework in which the fundamental mechanism for sensitivity is identical for clock and atom interferometer proposals, with the key difference being whether or not the atoms are tightly confined by an external potential. With this interpretation in mind, we propose two major enhancements to detectors using confined atoms, which allow for an enhanced sensitivity analogous to large momentum transfer used in atom interferometry (though with no transfer of momentum to the atoms), and a way to extend the useful coherence time of the sensor beyond the atom's excited-state lifetime.

  9. Atom inlays performed at room temperature using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Sugimoto, Yoshiaki; Abe, Masayuki; Hirayama, Shinji; Oyabu, Noriaki; Custance, Óscar; Morita, Seizo

    2005-02-01

    The ability to manipulate single atoms and molecules laterally for creating artificial structures on surfaces is driving us closer to the ultimate limit of two-dimensional nanoengineering. However, experiments involving this level of manipulation have been performed only at cryogenic temperatures. Scanning tunnelling microscopy has proved, so far, to be a unique tool with all the necessary capabilities for laterally pushing, pulling or sliding single atoms and molecules, and arranging them on a surface at will. Here we demonstrate, for the first time, that it is possible to perform well-controlled lateral manipulations of single atoms using near-contact atomic force microscopy even at room temperature. We report the creation of 'atom inlays', that is, artificial atomic patterns formed from a few embedded atoms in the plane of a surface. At room temperature, such atomic structures remain stable on the surface for relatively long periods of time.

  10. The Cold War legacy of regulatory risk analysis: The Atomic Energy Commission and radiation safety

    NASA Astrophysics Data System (ADS)

    Boland, Joseph B.

    From its inception in 1946 the Atomic Energy Commission pioneered the use of risk analysis as a mode of regulatory rationality and political rhetoric, yet historical treatments of risk analysis nearly always overlook the important role it played in the administration of atomic energy during the early Cold War. How this absence from history has been achieved and why it characterizes most historical accounts are the subjects of Chapter II. From there, this study goes on to develop the thesis that the advent of the atomic bomb was a world-shattering event that forced the Truman administration to choose between two novel alternatives: (1) movement towards global governance based initially on cooperative control of atomic energy or (2) unsparing pursuit of nuclear superiority. I refer to these as nuclear internationalism and nuclear nationalism, respectively. Each defined a social risk hierarchy. With the triumph of nuclear nationalism, nuclear annihilation was designated the greatest risk and a strong nuclear defense the primary means of prevention. The AEC's mission in the 1950s consisted of the rapid development of a nuclear arsenal, continual improvements in weapons technologies, and the promotion of nuclear power. The agency developed a risk-based regulatory framework through its dominant position within the National Committee on Radiation Protection. It embraced a technocratic model of risk analysis whose articulation and application it controlled, largely in secret. It used this to undergird a public rhetoric of reassurance and risk minimization. In practice, safety officials adjusted exposure levels within often wide parameters and with considerable fluidity in order to prevent safety concerns from interfering with operations. Secrecy, the political climate of the time, and a lack of accountability enabled the agency to meld technical assessments with social value judgments in a manner reflective of nuclear nationalism's risk hierarchy. In the late fifties

  11. Fallout isotope chronology of the near-surface sediment record of Lake Bolătău.

    PubMed

    Bihari, Árpád; Karlik, Máté; Mîndrescu, Marcel; Szalai, Zoltán; Grădinaru, Ionela; Kern, Zoltán

    2018-01-01

    Fallout isotope ( 210 Pb ex, 137 Cs and 241 Am) based dating has been carried out on the near-surface sediment core collected from Lake Bolătău-Feredeu (Bukovina, Romania). The motivation was to improve the chronology of this recent section in connection with significant fluctuations observed in sediment accumulation rates, particle size distribution and primordial radioisotope (i.e. 40 K and 232 Th) composition. Previously only an extrapolation of a broad-range OxCal age-depth model, which was based on 8 AMS radiocarbon dates from the deeper part of a parallel sediment sequence and tentatively validated for the upper part using the double peaks of the 137 Cs activity concentration distribution, was available for the studied section (1-24 cm). Parallel to the previous 137 Cs measurement, 210 Pb and 226 Ra (for a more detailed, 210 Pb ex -based chronology), 241 Am (for an additional time-marker), as well as 40 K and 232 Th concentrations have also been determined by gamma-spectrometry. In case of the 210 Pb ex -based chronology, due to a large deviation from a pure exponential distribution, the Constant Flux (CF) model has been used for the calculation of sediment ages and accumulation rates. Although the broad-range OxCal and the CF model were broadly similar down to 22 cm, the 210 Pb ex -based ages are clearly superior in terms of uncertainty in the uppermost 12 cm, while the broad-range model has smaller uncertainty below 20 cm (>150 years). The CF model gave an average mass accumulation rate of (0.08 ± 0.03) g cm -2 yr -1 for sections 0-11 cm, and (0.03 ± 0.01) g cm -2 yr -1 for sections 12-22 cm, respectively. Significant changes have been observed in the depth distribution of both the particle size distribution and the elemental/isotopic composition of the sediment record, most likely related to the variation observable in the intensity and volume of precipitation in the catchment. The obtained high-resolution records of Lake Bolătău, including

  12. Estimation of sediment residence times in subtropical highland catchments of central Mexico combining river gauging and fallout radionuclides

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Némery, Julien; Gratiot, Nicolas; Duvert, Clément; Lefèvre, Irène; Ayrault, Sophie; Esteves, Michel; Bonté, Philippe

    2010-05-01

    Subtropical regions of the world are affected by intense soil erosion associated with deforestation, overgrazing and cropping intensification. This land degradation leads to important on-site (e.g. decrease in soil fertility) and off-site impacts (e.g. reservoir sedimentation, water pollution). This study determined the mean sediment residence times in soils and rivers of three catchments (3 - 12 km²) with contrasted land uses (i.e. cropland, forests, rangelands, extended gully networks) located in highlands of the transvolcanic belt of central Mexico. Calculations were based on rainfall and river gauging as well as on fallout radionuclide measurements (Be-7, Cs-137, Pb-210). Atmospheric deposition of Be-7 and Pb-210 was estimated based on the analysis of rainfall precipitated samples. Rainfall samples were collected all throughout the rainy season in order to take account of the temporal variations of the radionuclide fluxes. Furthermore, sampling of suspended sediment was conducted at the outlet of each catchment during most of the storms that occurred throughout the 2009 rainy season. Be-7, Cs-137 and Pb-210 concentrations of this sediment were determined by gamma-spectrometry. A two-box balance model was then used to estimate the sediment residence time and the inventory of radionuclides in the three selected catchments. This model subdivided each catchment into two boxes: (i) a "soil-box" characterised by low transport velocities and hence long radionuclide residence times and (ii) a "river-box" covering the river surface and its surroundings characterised by quicker exchanges and shorter radionuclide residence times. Input and output fluxes of sediment and radionuclides were taken into account in each box. Radioactive decay during the residence time of sediment was also considered. The mean residence time of sediment in soils ranged between 13,300 - 28,500 years. In contrast, sediment residence time in rivers was much shorter, fluctuating between 28 and 393

  13. Understanding sediment dynamics in rivers using fallout radionuclides: How to move forward from the lessons learnt in a tropical catchment

    NASA Astrophysics Data System (ADS)

    Evrard, Olivier; Laceby, J. Patrick; Huon, Sylvain; Gourdin, Elian; Lefèvre, Irène; Sengtaheuanghoung, Oloth; Ayrault, Sophie; Ribolzi, Olivier

    2015-04-01

    Land use change and the concomitant acceleration of soil erosion have led to an increase in sediment supply to rivers worldwide. This degradation results in significant on-site (e.g., decrease in soil fertility) and off-site impacts (e.g., reservoir siltation and degradation of water quality). To implement effective sediment mitigation measures, it is necessary to clearly understand catchment sediment sources and their spatial temporal dynamics. Fallout radionuclides characterized by different half-lives and origins (Be-7 - 53 d; Pb-210 - 22 y; Cs-137 - 30 y) provide important information required to quantify the dominant sources of sediment and also their temporal dynamics. However, the current methods have several limitations, and the hypotheses underpinning this technique require further verification. To examine these assumptions, we investigated sediment dynamics in a 10-km² catchment in Northern Laos during the first flood of the monsoon in June 2014. Before this event, Be-7 that labelled soil and sediment during previous storms in 2013 had completely decayed, and the material stored in the river channel was shown to be depleted in Be-7. A large set of samples (n=97) was collected to characterize the sources that may supply sediment to the river. In addition, suspended sediment (n=17) was collected in the river at several stations during this the first flood of the monsoon. A distribution modelling approach was used to quantify the relative contributions of surface and subsurface sources. Further we modelled the proportions of material eroded during this storm compared to material that previously eroded before the storm and was remobilized during this recent event. The results demonstrate that the majority of sediment transported during the first erosive storm of the year consists of older, remobilized material. Furthermore, the contribution of sediment supplied to the river by subsurface sources (i.e., channel bank erosion) increases downstream. In the

  14. Peak power ratio generator

    DOEpatents

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  15. Peak power ratio generator

    DOEpatents

    Moyer, Robert D.

    1985-01-01

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  16. The human sex odds at birth after the atmospheric atomic bomb tests, after Chernobyl, and in the vicinity of nuclear facilities.

    PubMed

    Scherb, Hagen; Voigt, Kristina

    2011-06-01

    Ever since the discovery of the mutagenic properties of ionizing radiation, the possibility of birth sex odds shifts in exposed human populations was considered in the scientific community. Positive evidence, however weak, was obtained after the atomic bombing of Japan. We previously investigated trends in the sex odds before and after the Chernobyl Nuclear Power Plant accident. In a pilot study, combined data from the Czech Republic, Denmark, Finland, Germany, Hungary, Norway, Poland, and Sweden between 1982 and 1992 showed a downward trend in the sex odds and a significant jump in 1987, the year immediately after Chernobyl. Moreover, a significant positive association of the sex odds between 1986 and 1991 with Chernobyl fallout at the district level in Germany was observed. Both of these findings, temporality (effect after exposure) and dose response association, yield evidence of causality. The primary aim of this study was to investigate longer time periods (1950-2007) in all of Europe and in the USA with emphasis on the global atmospheric atomic bomb test fallout and on the Chernobyl accident. To obtain further evidence, we also analyze sex odds data near nuclear facilities in Germany and Switzerland. DATA AND STATISTICAL METHODS: National gender-specific annual live births data for 39 European countries from 1975 to 2007 were compiled using the pertinent internet data bases provided by the World Health Organization, United Nations, Council of Europe, and EUROSTAT. For a synoptic re-analysis of the period 1950 to 1990, published data from the USA and from a predominantly western and less Chernobyl-exposed part of Europe were studied additionally. To assess spatial, temporal, as well as spatial-temporal trends in the sex odds and to investigate possible changes in those trends after the atomic bomb tests, after Chernobyl, and in the vicinity of nuclear facilities, we applied ordinary linear logistic regression. Region-specific and eventually changing spatial

  17. Cavity enhanced atomic magnetometry

    PubMed Central

    Crepaz, Herbert; Ley, Li Yuan; Dumke, Rainer

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations. PMID:26481853

  18. Liquid seeding atomizer

    NASA Technical Reports Server (NTRS)

    Seegmiller, Henry L. B. (Inventor)

    1987-01-01

    An atomizer for a liquid having an air supply is described. Liquid supply tubes extend longitudinally along the air supply tube. The air supply tube has at least one air orifice extending from an inner surface of the tube through the tube. The liquid supply tubes are positioned on either side of the air orifices and the liquid tubes are sealed to the air supply tube. The liquid supply tubes with facing liquid orifices are positioned adjacent to each of the air orifices. The liquid supply tubes are laterally spaced apart at the liquid orifices at a distance less than the diameter of the air orifices to enable a beneficial venturi effect when the atomizer is in operation.

  19. Atomic Disorder in Tetrahedrite

    NASA Astrophysics Data System (ADS)

    Salasin, John Robert; Chakoumakos, Bryan; Rawn, Claudia; May, Andrew; Lara-Curzio, Edgar; McGuire, Michael; Cao, Huibo

    2015-03-01

    Thermoelectrics (TE) are materials which turn heat energy into electrical energy with applications spanning multiple disciplines including space exploration, Peltier cooling, and engine efficiency. Tetrahedrite is a copper sulfosalt with the general formula Cu12-xMx(Sb,As)4S13. Where M denotes a Cu2+ site frequently replaced in natural tetrahedrite with Zn, Fe, Hg, or Mn. It has a cubic structure with an I-43m symmetry, a = 10.4 Å, and only a handful of adjustable parameters. This structural study corroborates theoretical calculations on atomic disorder. Positional disorder of the trigonally coordinated Cu(2) site is suggested from the temperature dependence of the atomic displacement parameters determine from single-crystal x-ray and neutron diffraction. The displacements are extremely anisotropic for Cu(2) with a maximum rms static displacement of ~ 0.25 Å.

  20. Cavity enhanced atomic magnetometry.

    PubMed

    Crepaz, Herbert; Ley, Li Yuan; Dumke, Rainer

    2015-10-20

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.