WorldWideScience

Sample records for fallout debris originating

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

    Energy Technology Data Exchange (ETDEWEB)

    Williamson, Todd L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tenner, Travis Jay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bonamici, Chloe Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kinman, William Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollington, Anthony Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Steiner, Robert Ernest [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    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.

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

    Science.gov (United States)

    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.

  3. Radioecological transfer of {sup 137}Cs from ground deposition to man from Chernobyl debris and from nuclear weapons fallout in different Swedish populations

    Energy Technology Data Exchange (ETDEWEB)

    Raeaef, C.L. [Malmoe Univ. Hospital, Lund Univ., Dept. of Radiation Physics, Malmoe (Sweden)

    2005-07-01

    A comparison of the estimated committed effective dose per unit activity deposition on ground was made between different critical groups in Sweden. The time-integrated aggregate transfer of {sup 137}Cs for the global fallout was 2-3 times higher than from Chernobyl debris for Swedish urban populations. For reindeer herders this difference is even more marked, with a factor of three to four higher time-integrated transfer factor of nuclear weapons fallout. Considering the transfer of Chernobyl {sup 137}Cs debris the time-integrated transfer factor appears to be more than 25 times higher for reindeer herders in Sweden than for the urban reference groups. An even more pronounced relative difference between the time integrated aggregate transfer was observed between reindeer herders and urban reference populations for the pre-Chernobyl fallout (a factor of 30). The projected committed effective dose from internal contamination of Chernobyl {sup 137}Cs per unit activity deposition is observed to be 2030 {mu}Sv/kBq m{sup -2}. The highest values in Sweden are obtained for reindeer herders with an estimated radioecological transfer of 0.5 mSv/kBq m{sup -2}. (au)

  4. Origins and Interpretation of Tidal Debris

    CERN Document Server

    Johnston, Kathryn V

    2016-01-01

    The stellar debris structures that have been discovered around the Milky Way and other galaxies are thought to be formed from the disruption of satellite stellar systems --- dwarf galaxies or globular clusters --- by galactic tidal fields. The total stellar mass in these structures is typically tiny compared to the galaxy around which they are found, and it is hence easy to dismiss them as inconsequential. However, they are remarkably useful as probes of a galaxy's history (as described in this chapter) and mass distribution (covered in a companion chapter in this volume). This power is actually a consequence of their apparent insignificance: their low contribution to the overall mass makes the physics that describes them both elegant and simple and this means that their observed properties are relatively easy to understand and interpret.

  5. Origin and abundance of beach debris in the Balearic Islands

    Directory of Open Access Journals (Sweden)

    Lorena Martinez-Ribes

    2007-06-01

    Full Text Available The abundance, nature and possible sources of litter on 32 beaches on the Balearic Islands (Mediterranean Sea were investigated in 2005. Mean summer abundances in the Balearics reached approximately 36 items m-1, with a corresponding weight of 32±25 g m-1, which is comparable to the results of other studies in the Mediterranean. Multivariate analyses (principal component analysis and redundancy analysis confirmed strong similarities between islands and a statistically significant seasonal evolution of litter composition and abundance. In summer (the high tourist season, debris contamination expressed as item abundance was double that in the low season and showed a heterogeneous nature associated with beach use. Cigarette butts were the most abundant item, accounting for up to 46% of the objects observed in the high tourist season. In contrast, plastics related to personal hygiene/medical items were predominant in wintertime (67% and natural wood was the most important debris by weight (75%. In both seasons, litter characteristics suggested a strong relationship with local land-based origins. While beach users were the main source of summer debris, low tourist season litter was primarily attributed to drainage and outfall systems.

  6. Radioactive fallout

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-12-01

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

  7. Contrasting origin of two clay-rich debris flows at Cayambe Volcanic Complex, Ecuador

    Science.gov (United States)

    Detienne, M.; Delmelle, P.; Guevara, A.; Samaniego, P.; Opfergelt, S.; Mothes, P. A.

    2017-04-01

    We investigate the sedimentological and mineralogical properties of a debris flow deposit west of Cayambe Volcanic Complex, an ice-clad edifice in Ecuador. The deposit exhibits a matrix facies containing up to 16 wt% of clays. However, the stratigraphic relationship of the deposit with respect to the Canguahua Formation, a widespread indurated volcaniclastic material in the Ecuadorian inter-Andean Valley, and the deposit alteration mineralogy differ depending on location. Thus, two different deposits are identified. The Río Granobles debris flow deposit ( 1 km3) is characterised by the alteration mineral assemblage smectite + jarosite, and sulphur isotopic analyses point to a supergene hydrothermal alteration environment. This deposit probably derives from a debris avalanche initiated before 14-21 ka by collapse of a hydrothermally altered rock mass from the volcano summit. In contrast, the alteration mineralogy of the second debris flow deposit, which may itself comprise more than one unit, is dominated by halloysite + smectite and relates to a shallower and more recent (3200 m) volcanic soils. Our study reinforces the significance of hydrothermal alteration in weakening volcano flanks and in favouring rapid transformation of a volcanic debris avalanche into a clay-rich debris flow. It also demonstrates that mineralogical analysis provides crucial information for resolving the origin of a debris flow deposit in volcanic terrains. Finally, we posit that slope instability, promoted by ongoing subglacial hydrothermal alteration, remains a significant hazard at Cayambe Volcanic Complex.

  8. Dusty Disks around White Dwarfs I: Origin of Debris Disks

    CERN Document Server

    Dong, Ruobing; Lin, D N C; Liu, X -W

    2010-01-01

    A significant fraction of the mature FGK stars have cool dusty disks at least an orders of magnitudes brighter than the solar system's outer zodiacal light. Since such dusts must be continually replenished, they are generally assumed to be the collisional fragments of residual planetesimals analogous to the Kuiper Belt objects. At least 10% of solar type stars also bear gas giant planets. The fraction of stars with known gas giants or detectable debris disks (or both) appears to increase with the stellar mass. Here, we examine the dynamical evolution of systems of long-period gas giant planets and residual planetesimals as their host stars evolve off the main sequence, lose mass, and form planetary nebula around remnant white dwarf cores. The orbits of distant gas giant planets and super-km-size planetesimals expand adiabatically. During the most intense AGB mass loss phase, sub-meter-size particles migrate toward their host stars due to the strong hydrodynamical drag by the intense stellar wind. Along their ...

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

    Science.gov (United States)

    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

  10. Pedimentation versus debris-flow origin of plateau-side desert terraces in southern Utah.

    Science.gov (United States)

    Williams, V.S.

    1984-01-01

    Plateau-side terraces in arid areas around the world are commonly described as pediment remnants, although, in many cases, they may have been formed by debris-flow deposition. Pediments do exist in the area of the Aquarius and Kaiparowits Plateaus of southern Utah; however, many alluvial terraces that were classified by previous workers as pediments are actually formed of thick deposits of sediment released into valleys by episodic landslide events. Although both pediment and debris-flow depositional terraces have smooth, alluvium-covered upper surfaces, the two can be distinguished by the shape of the underlying bedrock surface and the process of formation. The relation of younger terraces to landsliding is clear, because the terrace surfaces are graded to the toes of slide lobes, but the origin of older terraces is less obvious, because older lobes of slide debris have generally been removed by erosion. -from Author

  11. Human metabolism and ecological transfer of radioactive caesium: Comparative studies of Chernobyl debris and nuclear weapons fallout, in Southern Sweden and in Bryansk, Russia

    Science.gov (United States)

    Raaf, Christopher Leopold

    The whole-body content of radiocaesium was measured in a South-Swedish urban group of people residing in the city of Lund (55.7°N, 13.2°E) between 1960 and 1994. The results from the survey have been analysed in order to estimate the ecological half-time, Teff,eco, of fallout radiocaesium and the aggregate transfer from ground deposition to man in the region. After 1987, the biological half-times, Ts, of 137Cs and 40K in man were also determined in the reference group through whole-body content measurements in combination with 24-hour urine sampling. Relationships between 24-hour urinary excretion and body burden of 137Cs in the group together with data from the literature were then applied to urine samples collected in 1994 and 1995 from adult subjects living in the highly contaminated region of Bryansk, Russia, in order to estimate their average body burden of 137Cs. The equivalent biological half-time for 137Cs in females of the Lund reference group was, on average (+/-1 WSE), 66 +/- 3 d, which agrees with other findings, whereas the value for the males, 81 +/- 4 d, was, on average, significantly lower than what is found in the literature. This is partly explained by the elevated mean age and relatively low mean body muscle mass of the males investigated in the group during the post-Chernobyl study period. The effective ecological half-time for 137Cs from Chernobyl was found to be 1.8 +/- 0.2 y. The aggregate transfer of 137Cs from deposition to mean activity concentration in man was estimated to be 1.7 Bq kg-1/kBq m-2. These vales may be compared with an effective ecological half-time of 1.3 years found in the reference group in the 1960s, and an aggregate transfer factor of 9.8 Bq kg-1/kBq m-2. The average committed effective dose from ingested 137Cs Chernobyl fallout in the study group was estimated to be 0.02 mSv and from the nuclear weapons fallout to 0.20 mSv. The estimates of whole-body content of 137Cs in the Russian subjects obtained through

  12. Onset of submarine debris flow deposition far from original giant landslide.

    Science.gov (United States)

    Talling, P J; Wynn, R B; Masson, D G; Frenz, M; Cronin, B T; Schiebel, R; Akhmetzhanov, A M; Dallmeier-Tiessen, S; Benetti, S; Weaver, P P E; Georgiopoulou, A; Zühlsdorff, C; Amy, L A

    2007-11-22

    Submarine landslides can generate sediment-laden flows whose scale is impressive. Individual flow deposits have been mapped that extend for 1,500 km offshore from northwest Africa. These are the longest run-out sediment density flow deposits yet documented on Earth. This contribution analyses one of these deposits, which contains ten times the mass of sediment transported annually by all of the world's rivers. Understanding how this type of submarine flow evolves is a significant problem, because they are extremely difficult to monitor directly. Previous work has shown how progressive disintegration of landslide blocks can generate debris flow, the deposit of which extends downslope from the original landslide. We provide evidence that submarine flows can produce giant debris flow deposits that start several hundred kilometres from the original landslide, encased within deposits of a more dilute flow type called turbidity current. Very little sediment was deposited across the intervening large expanse of sea floor, where the flow was locally very erosive. Sediment deposition was finally triggered by a remarkably small but abrupt decrease in sea-floor gradient from 0.05 degrees to 0.01 degrees. This debris flow was probably generated by flow transformation from the decelerating turbidity current. The alternative is that non-channelized debris flow left almost no trace of its passage across one hundred kilometres of flat (0.2 degrees to 0.05 degrees) sea floor. Our work shows that initially well-mixed and highly erosive submarine flows can produce extensive debris flow deposits beyond subtle slope breaks located far out in the deep ocean.

  13. Counter-Orbiting Tidal Debris as the Origin of the MW DoS

    CERN Document Server

    Pawlowski, Marcel S

    2011-01-01

    The Milky Way satellite galaxies show a phase-space distribution that is not expected from the standard scenario of galaxy formation. This is a strong hint at them being of tidal origin, which would naturally explain their spacial distribution in a disc of satellites. It is shown that also their orbital directions can be reproduced with the debris of galaxy collisions. Both co- and counter-orbiting satellites are formed naturally in merger and fly-by interactions.

  14. Counter-orbiting tidal debris as the origin of the MW DoS

    Directory of Open Access Journals (Sweden)

    Pawlowski M.S.

    2012-02-01

    Full Text Available The Milky Way satellite galaxies show a phase-space distribution that is not expected from the standard scenario of galaxy formation. This is a strong hint at them being of tidal origin, which would naturally explain their spacial distribution in a disc of satellites. It is shown that also their orbital directions can be reproduced with the debris of galaxy collisions. Both co- and counter-orbiting satellites are formed naturally in merger and fly-by interactions.

  15. Early precambrian asteroid impact-triggered tsunami: excavated seabed, debris flows, exotic boulders, and turbulence features associated with 3.47-2.47 Ga-old asteroid impact fallout units, Pilbara Craton, Western Australia.

    Science.gov (United States)

    Glikson, Andrew Y

    2004-01-01

    basal microbreccia veins suggests tsunami-induced hydraulic pressures locally exceeded lithostatic pressure. Late-stage settling of spherule-bearing mud clouds in the wake of the tsunami is represented by an abundance of spherules in the uppermost microbreccia zones of the megabreccia pile. From the deep below-wave base facies of the Carawine Dolomite, tsunami wave amplitudes may have exceeded 200 m depth. The approximately 2.47-2.50 Ga DGS4 (S4 Macroband, Dales Gorge Member, Brockman Iron Formation) fallout units include exotic chert and carbonate boulders transported by tsunami following settling of a 10-20-cm-thick microkrystite and microtektite-rich unit. Seismic perturbations preceding deposition of the JIL and SMB fallout units are marked by rip-up clasts. The geochemistry of microkrystites and microtektites suggests impact fallout originated from impacts in simatic/oceanic crustal regions, although tsunami waves may have originated from seismically reactivated faults and plate margins located at distance from the impact craters.

  16. Human metabolism and ecological transfer of radioactive caesium. Comparative studies of Chernobyl debris and nuclear weapons fallout, in southern Sweden and in Bryansk, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Raeaef, C.L

    2000-05-01

    The whole-body content of radiocaesium was measured in a South Swedish urban group of people residing in the city of Lund between 1960 and 1994. The results from the survey have been analysed in order to estimate the ecological half time, T{sub eff,eco} of fallout radiocaesium, and the aggregate transfer from ground deposition to man in the region. After 1987, the biological half times, T{sub e} of {sup 137}Cs and {sup 40}K in man were also determined in the reference group through whole-body content measurements in combination with 24-hour urine sampling. Relationships between 24-hour urinary excretion and body burden of {sup 137}Cs in the group together with data from the literature were then applied to urine samples collected in 1994 and 1995 from adult subjects living in the highly contaminated region of Bryansk, Russia, in order to estimate their average body burden of {sup 137}Cs. The equivalent biological half-time for {sup 137}Cs in females of the Lund reference group was, on average 66{+-}3 d, which agrees with other findings, whereas the value for the males, 81{+-}4 d, was, on average, significantly lower than what is found in the literature. This is partly explained by the elevated mean age and relatively low mean body muscle mass of the males investigated. The {sup 137}Cs from nuclear weapons tests in the 1950s and 1960s still gave a significant contribution to the total {sup 137}Cs levels in man during the post-Chernobyl study period (1987-1994). About 10% of the peak post-Chernobyl concentration level of {sup 137}Cs (3.5-4 Bq/kg) in 1987, was attributed to pre-Chernobyl {sup 137}Cs. The effective ecological half-time for {sup 137}Cs from Chernobyl was found to be 1.8{+-}0.2 y. The time-integrated aggregate transfer of {sup 137}Cs from ground deposition to mean activity concentration in man was estimated to be 0.4 Bq/kg/kBq/m{sup 2}. These values may be compared with an effective ecological half-time of 1.3 years found in the Lund reference group in

  17. Location and origin of dust in circumstellar debris disks: A mid-infrared imaging study

    Science.gov (United States)

    Moerchen, Margaret Marie

    Approximately one third of A-type stars host dusty disks beyond the expected timescales for dissipation of the primordial disk material. The primordial dust particles may either be blown out by radiation pressure from the star or they may experience destructive collisions that generate smaller particles that are then blown out of the system. We infer from the sustained presence of the dust that it must be resupplied through collisions of already-formed planets and planetesimals or through the sublimation of cometary bodies, and systems with such dust are called debris disks. Since the 1984 discovery of the debris disk Vega, observations of circumstellar debris disks have revealed the presence planetary systems that would otherwise have remained unknown. In this work, we set out to find asymmetric structures in debris disks that would indicate a physical process sculpting the disk, such as a catastrophic planetesimal collision that generates a bright region of newly-formed dust, or a clumpy pattern comprised of dust that is trapped in an orbital resonance with a giant planet. We obtained high spatial resolution ([Special characters omitted.] 0.5") images of the thermally emitting dust in 21 debris disk candidates (some of which are now known not to be debris disks), and in most cases we did not detect any brightness asymmetry nor was the source even spatially resolved. However, among the resolved disks, we have discovered several structures that may be analogous to those in our own solar system, such as a potential asteroid belts (in z Lep) and a snow line (in HD 32297). One brightness asymmetry is seen, in the disk of 16 HR 4796A, and we have determined that the bright side of the disk is also hotter than the opposite side. We review the possible origins of such a temperature asymmetry in the dust disk, such as pericenter glow and resonant trapping, and this investigation is ongoing. More generally, two disk archetypes are observed among all of the disks in this

  18. Age, origin and evolution of Antarctic debris-covered glaciers: Implications for landscape evolution and long-term climate change

    Science.gov (United States)

    Mackay, Sean Leland

    Antarctic debris-covered glaciers are potential archives of long-term climate change. However, the geomorphic response of these systems to climate forcing is not well understood. To address this concern, I conducted a series of field-based and numerical modeling studies in the McMurdo Dry Valleys of Antarctica (MDV), with a focus on Mullins and Friedman glaciers. I used data and results from geophysical surveys, ice-core collection and analysis, geomorphic mapping, micro-meteorological stations, and numerical-process models to (1) determine the precise origin and distribution of englacial and supraglacial debris within these buried-ice systems, (2) quantify the fundamental processes and feedbacks that govern interactions among englacial and supraglacial debris, (3) establish a process-based model to quantify the inventory of cosmogenic nuclides within englacial and supraglacial debris, and (4) isolate the governing relationships between the evolution of englacial /supraglacial debris and regional climate forcing. Results from 93 field excavations, 21 ice cores, and 24 km of ground-penetrating radar data show that Mullins and Friedman glaciers contain vast areas of clean glacier ice interspersed with inclined layers of concentrated debris. The similarity in the pattern of englacial debris bands across both glaciers, along with model results that call for negligible basal entrainment, is best explained by episodic environmental change at valley headwalls. To constrain better the timing of debris-band formation, I developed a modeling framework that tracks the accumulation of cosmogenic 3He in englacial and supraglacial debris. Results imply that ice within Mullins Glacier increases in age non-linearly from 12 ka to ˜220 ka in areas of active flow (up to >> 1.6 Ma in areas of slow-moving-to-stagnant ice) and that englacial debris bands originate with a periodicity of ˜41 ka. Modeling studies suggest that debris bands originate in synchronicity with changes in

  19. Radioactive fallout from Chinese nuclear weapons test

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, C.W.; Soldat, J.K.; Silker, W.B.; Perkins, R.W.

    1976-09-26

    Radioactive fallout from this Chinese nuclear test resulted in measurable deposition of short-lived debris over much of the United States. The fallout levels varied by more than 1000-fold and showed significant temporary or spatial fractionation with higher levels of deposition being associated with rain. The particle size with which the airborne debris was associated decreased continuously with time following detonation and a substantial fraction of the {sup 131}I was associated with inorganic and organic gases. The potential radiation dose to an infant consuming milk produced at the location of the highest concentration of {sup 131}I measured on grass was estimated to be {approximately}l rem. This dose is about 50 times the annual dose received in the vicinity of a power reactor operating under the existing US Nuclear Regulatory Commission design guides. The potential upper limit thyroid dose for the population of 17 eastern seaboard states from this single test was estimated to be about 2.4 {times} 10{sup 6} man-thyroid-rem under the assumption that all dairy cows remained on fresh pasture throughout the month following the initial decomposition of fallout debris. This dose is about 200 times the estimated dose from currently operating nuclear power reactors and about 50 times the annual US population thyroid dose that would be received from 500 GWe of nuclear power reactors in the year 2000.

  20. Origin and evolution of two-component debris discs and an application to the q$^1$ Eridani system

    CERN Document Server

    Schüppler, Christian; Löhne, Torsten; Booth, Mark; Kirchschlager, Florian; Wolf, Sebastian

    2016-01-01

    Many debris discs reveal a two-component structure, with an outer Kuiper-belt analogue and a warm inner component whose origin is still a matter of debate. One possibility is that warm emission stems from an "asteroid belt" closer in to the star. We consider a scenario in which a set of giant planets is formed in an initially extended planetesimal disc. These planets carve a broad gap around their orbits, splitting up the disc into the outer and the inner belts. After the gas dispersal, both belts undergo collisional evolution in a steady-state regime. This scenario is explored with detailed collisional simulations involving realistic physics to describe a long-term collisional depletion of the two-component disc. We find that the inner disc may be able to retain larger amounts of material at older ages than thought before on the basis of simplified analytic models. We show that the proposed scenario is consistent with a suite of thermal emission and scattered light observational data for a bright two-tempera...

  1. Arroyo el Mimbral, Mexico, K/T unit: Origin as debris flow/turbidite, not a tsunami deposit

    Science.gov (United States)

    Bohor, Bruce F.; Betterton, William J.

    1993-01-01

    Coarse, spherule-bearing, elastic units have been discovered at 10 marine sites that span the K/T boundary in northeastern Mexico. We examined one of the best exposed sites in Arroyo el Mimbral, northwest of Tampico. The Mimbral outcrop displays a layered elastic unit up to 3 m thick enclosed by marly limestones of the Mendez (Latest Maastrichian) and Velasco (Earliest Danian) Formations. At its thickest point, this channelized elastic unit is comprised of 3 subunits: (1) a basal, poorly-sorted, ungraded calcareous spherule bed 1 m thick containing relict impact glass and shocked mineral grains, (2) a massive set of laminated calcite-cemented sandstones up to 2 m thick with plant debris at its base, (3) capped by a thin (up to 20 cm) set of rippled sandstone layers separated by silty mudstone drapes containing a small (921 pg/g) iridium anomaly. This tripartite elastic unit is conformably overlain by marls of the Velasco Formation. We also visited the La Lajilla site east of Ciudad Victoria; its stratigraphy is similar to Mimbral's, but its elastic beds are thinner and less extensive laterally. The Mimbral elastic unit has been interpreted previously as being deposited by a megawave or tsunami produced by an asteroid impact on nearby Yucatan (Chicxulub crater). However, a presumed 400-m paleodepth of water at the Mimbral site, channeling of the spherule subunit into the underlying Mendez Formation marls, and the overtopping of the basal, spherule-bearing subunit by the laminated sandstone subunit, all suggest a combined debris flow/turbidite origin for this elastic unit similar to that proposed for Upper Pleistocene sand/silt beds occurring elsewhere in the Gulf of Mexico. In this latter model, the sediment source region for the elastic unit is the lower continental shelf and slope escarpment. For the K/T unit at Mimbral, we propose that thick ejecta blanket deposits composed mostly of spherules were rapidly loaded onto the lower shelf and slope from an impact

  2. How to Make the 20-cent Fallout Meter

    Energy Technology Data Exchange (ETDEWEB)

    Meade, Roger Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rodriguez, Serena R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Alvarez, Luis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    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.

  3. Fallout: Its Characteristics and Management

    Science.gov (United States)

    1983-12-01

    uranium, plutonium , and tritium (from the lithium in the lithium deuteride ). These isotopes remain and contribute to the problem of long-term fallout...unspent uranium or plutonium fuel, activated bomb components) and any neutron-induced material from the surrounding explosion environment. General... plutonium ). The opposite is true of a dirty weapon. The radioactive yield of a weapon can be intentionally increased through "salting," a process whereby

  4. An interferometric study of the Fomalhaut inner debris disk. III. Detailed models of the exozodiacal disk and its origin

    CERN Document Server

    Lebreton, J; Augereau, J -C; Absil, O; Mennesson, B; Kama, M; Dominik, C; Bonsor, A; Vandeportal, J; Beust, H; Defrère, D; Ertel, S; Faramaz, V; Hinz, P; Kral, Q; Lagrange, A -M; Liu, W; Thébault, P

    2013-01-01

    [Abridged] Debris disks are extrasolar analogs to the solar system planetesimal belts. The star Fomalhaut harbors a cold debris belt at 140 AU as well as evidence of a warm dust component, which is suspected of being a bright analog to the solar system's zodiacal dust. Interferometric observations obtained with the VLTI and the KIN have identified near- and mid-infrared excesses attributed to hot and warm exozodiacal dust in the inner few AU of the star. We performed parametric modeling of the exozodiacal disk using the GRaTeR radiative transfer code to reproduce the interferometric data, complemented by mid- to far-infrared measurements. A detailed treatment of sublimation temperatures was introduced to explore the hot population at the sublimation rim. We then used an analytical approach to successively testing several source mechanisms. A good fit to the data is found by two distinct dust populations: (1) very small, hence unbound, hot dust grains confined in a narrow region at the sublimation rim of carbo...

  5. Chemical Classification of Space Debris

    Institute of Scientific and Technical Information of China (English)

    LI Chunlai; ZUO Wei; LIU Jianjun; OUYANG Ziyuan

    2004-01-01

    Space debris, here referring to all non-operating orbital objects, has steadily increased in number so that it has become a potential barrier to the exploration of space. The ever-increasing number of space debris pieces in space has created an increasingly threatening hazard to all on-the-orbit spacecraft, and all future space exploration activities have to be designed and operated with respect to the increasing threat posed by space debris. Generally, space debris is classified as large, medium and small debris pieces based on their sizes. The large debris piece is easily catalogued, but medium to small debris pieces are very difficult to track and also quite different in damage mechanisms from the large ones. In this paper, a scheme of chemical classification of space debris is developed. In our scheme, the first-order classification is employed to divide space debris into two groups: natural micrometeoroids and artificial space debris.The second-order classification is based on their chemical patterns and compositions. The natural micrometeoroids are further divided into three types, namely maric, metal and phyllosilicate micrometeorites, while the artificial space debris is divided into seven types, which are polymers, non-metal debris, metals and their alloys, oxides, sulphides and their analogs, halides and carbides. Of the latter seven types, some can also be further divided into several sub-types. Chemical classification of space debris is very useful for the study of the chemical damage mechanism of small debris pieces, and also is of great significance in constraining the origin and source of space debris and assessing their impact on spacecraft and human space activities.

  6. Estimating Cs-137 fallout inventories in Iceland from precipitation data

    Energy Technology Data Exchange (ETDEWEB)

    Palsson, S.E.; Sigurgeirsson, M.A.; Gudnason, K. [Icelandic Radiation Protection Inst., Reykjavik (Iceland); Arnalds, O. [Agricultural Research Inst., Reykjavik (Iceland); Howard, B.J.; Wright, S.M. [Centre for Ecology and Hydrology Merlewood, Cumbria, (United Kingdom); Palsdottir, I. [Iceland Meteorological Office, Reykjavik (Iceland)

    2002-12-01

    Iceland was identified in the Arctic Monitoring and Assessment Programme (AMAP) as one of the Arctic areas which received the most global fallout from atmospheric nuclear weapons tests, due to relatively high precipitation rates compared with much of the Arctic and sub arctic. Cs-137 in the Icelandic terrestrial ecosystem almost entirely originates from the nuclear weapons tests carried out in the atmosphere until the early sixties. Fallout was greatest in mid nineteen sixties. Additional fallout from the accident at the Chernobyl Nuclear Power Plant was relatively small. The study gave preliminary information on the spatial variation in {sup 137} Cs deposition in Iceland, especially in areas used for agriculture. The objectives of the study were (1) to measure the spatial variation of radiocaesium inventories in soils in Iceland and (2) to compare the results with different approaches to predicting {sup 137} Cs contents in soil. This quantification is a necessary first step in an evaluation of vulnerability to radiocaesium deposition in Iceland. It is anticipated that Icelandic soils could be highly vulnerable to radiocaesium due to their volcanic nature and consequent lack of illitic minerals, as has been suggested by initial chemical studies on the properties of soils in the Nordic countries. (ln)

  7. Radioactive fallout and neural tube defects

    Directory of Open Access Journals (Sweden)

    Nejat Akar

    2015-10-01

    Full Text Available Possible link between radioactivity and the occurrence of neural tube defects is a long lasting debate since the Chernobyl nuclear fallout in 1986. A recent report on the incidence of neural defects in the west coast of USA, following Fukushima disaster, brought another evidence for effect of radioactive fallout on the occurrence of NTD’s. Here a literature review was performed focusing on this special subject.

  8. Post-Chernobyl fallout in Romania

    Energy Technology Data Exchange (ETDEWEB)

    Osvath, I.; Dovlete, C. [Inst. of Environmental Research and Engineering, Environmental Radioactivity Laboratory, Bucharest (Romania)

    1992-07-01

    As part of the Romanian environmental radioactivity monitoring programme, fallout samples have been systematically collected and analyzed for gamma emitters. Chernobyl fallout space-time patterns. radionuclide concentration ratios and deposition velocities have been determined. The resuspension process has been studied, environmental half-lives for {sup 137}Cs and resuspension factors have been evaluated. Hot particles have been identified in some of the deposition samples. (author)

  9. Building Protection Against External Ionizing Fallout Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, Michael B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homann, Steven G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    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. Fallout radiation effects analysis methodology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1988-03-31

    Fallout radiation is viewed by the weapons effects community as a potentially serious impediment to maintaining or restoring critical National Security Emergency Preparedness (NSEP) telecommunication capabilities in a nuclear environment. The OMNCS' Electromagnetic Pulse Mitigation Program is designed, in part, to identify the survival probability (survivability) of the nation's NSEP telecommunications infrastructure against fallout radiation effects. The OMNCS (Office of the Manager National Communications System) is developing a balanced approach consisting of fallout radiation stress tests on the electronic piece-parts and the use of estimated performance measures of telecommunication network elements in network simulation models to predict user connectivity levels. It is concluded that, given limited available data, the proposed method can predict fallout radiation effects on network telecommunication equipment. The effects of fallout radiation are small at low dosage levels (bin 1 and bin 2). More pronounced variations in equipment performance were exhibited for radiation dosage in the 1k-5k Rads(Si) bin. Finally, the results indicate that by increasing the sample size to approximately 200 samples, the statistical quality of survivability predictions can be significantly improved.

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

    Science.gov (United States)

    Whitcomb, Robert Cleckley, Jr.

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

  12. Detecting debris flows using ground vibrations

    Science.gov (United States)

    LaHusen, Richard G.

    1998-01-01

    Debris flows are rapidly flowing mixtures of rock debris, mud, and water that originate on steep slopes. During and following volcanic eruptions, debris flows are among the most destructive and persistent hazards. Debris flows threaten lives and property not only on volcanoes but far downstream in valleys that drain volcanoes where they arrive suddenly and inundate entire valley bottoms. Debris flows can destroy vegetation and structures in their path, including bridges and buildings. Their deposits can cover roads and railways, smother crops, and fill stream channels, thereby reducing their flood-carrying capacity and navigability.

  13. Radioactive Fallout From Nuclear Weapons Testing ...

    Science.gov (United States)

    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.

  14. Fallout from Chernobyl [Letters to the editor

    Energy Technology Data Exchange (ETDEWEB)

    Williams, E.D. (Addenbrooke' s Hospital, Cambridge (United Kingdom)); Abelin, T.; Egger, M. (Bern Univ. (Switzerland)) (and others)

    1994-11-12

    Six brief letters discuss the possible health effects of fallout from the Chernobyl reactor accident including an increase in thyroid cancer in children in Belarus, chromosomal abnormalities in workers from Latvia who cleared up the Chernobyl accident site, an increased trisomy 21 in Berlin but a lack of increased childhood leukaemia incidence in Greece. (UK).

  15. Debris ingestion by juvenile marine turtles: an underestimated problem.

    Science.gov (United States)

    Santos, Robson Guimarães; Andrades, Ryan; Boldrini, Marcillo Altoé; Martins, Agnaldo Silva

    2015-04-15

    Marine turtles are an iconic group of endangered animals threatened by debris ingestion. However, key aspects related to debris ingestion are still poorly known, including its effects on mortality and the original use of the ingested debris. Therefore, we analysed the impact of debris ingestion in 265 green turtles (Chelonia mydas) over a large geographical area and different habitats along the Brazilian coast. We determined the death rate due to debris ingestion and quantified the amount of debris that is sufficient to cause the death of juvenile green turtles. Additionally, we investigated the original use of the ingested debris. We found that a surprisingly small amount of debris was sufficient to block the digestive tract and cause death. We suggested that debris ingestion has a high death potential that may be masked by other causes of death. An expressive part of the ingested debris come from disposable and short-lived products. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Chernobyl fallout in a Swedish spruce forest ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    McGee, E.J.; Synnott, H.J.; Johanson, K.J.; Fawaris, B.H.; Nielsen, S.P.; Horrill, A.D.; Kennedy, V.H.; Barbayiannis, N.; Veresoglou, D.S.; Dawson, D.E.; Colgan, P.A.; McGarry, A.T

    2000-03-01

    An assessment of the distribution of Chernobyl fallout in a Swedish forest was carried out and showed more than 95% of the {sup 137}Cs in the system to be of Chernobyl origin. The data show that approximately 87% of total fallout is found in soils, 6% in the bryophyte layer and 7% in standing biomass of trees. The mean deposition of {sup 137}Cs in the system (including soils, bryophytes, understorey vegetation, fungi, trees, moose and roe deer) was 54 kBq m{sup -2}. Fungi, understorey vegetation and ruminant populations collectively contained approximately 1% of total radiocaesium in the system. However, actual concentrations in these sample types were higher than in any other category, mostly exceeding the limit of 1500 Bq kg{sup -1} for consumption of wild produce in Sweden. These categories represent the principal foodstuffs responsible for radiation transfer to man from the system and though negligible in total biomass there is potential for significant dose transfer to individuals who are regular consumers of wild forest produce.

  17. An Introduction to Space Debris

    Science.gov (United States)

    Wright, David

    2008-04-01

    Space debris is any human-made object in orbit that no longer serves a useful purpose, including defunct satellites, discarded equipment and rocket stages, and fragments from the breakup of satellites and rocket stages. It is a concern because--due to its very high speed in orbit--even relatively small pieces can damage or destroy satellites in a collision. Since debris at high altitudes can stay in orbit for decades or longer, it accumulates as more is produced and the risk of collisions with satellites grows. Since there is currently no effective way to remove large amounts of debris from orbit, controlling the production of debris is essential for preserving the long-term use of space. Today there are 860 active satellites in orbit, supporting a wide range of civil and military uses. The 50 years of space activity since the launch of Sputnik 1 has also resulted in well over half a million pieces of orbiting debris larger than 1 cm in size. There are two main sources of space debris: (1) routine space activity and the accidental breakup of satellites and stages placed in orbit by such activity, and (2) the testing or use of destructive anti-satellite (ASAT) weapons that physically collide with satellites at high speed. The international community is attempting to reduce the first category by developing strict guidelines to limit the debris created as a result of routine space activities. However, the destruction of a single large spy satellite by an ASAT weapon could double the total amount of large debris in low earth orbit, and there are currently no international restrictions on these systems. This talk will give an introduction to what's in space, the origins of space debris, efforts to stem its growth, the threat it poses to satellites in orbit, and the long-term evolution of the debris population.

  18. FALLOUT RADIATION: EFFECTS ON THE SKIN

    Energy Technology Data Exchange (ETDEWEB)

    Conard, R. A.; Cronkite, E. P.; Bond, V. P.

    1963-02-06

    Until recently it has been generally assumed that injury to the skin from ionizing radiation was not a serious hazard associated with the detonation of nuclear dcvices. However, in 1954 the importance of this hazard became apparent when widespread lesions of the skin developed in a large group of people accidentally exposed to fallout radiation in the Marshall Islands following the experimental detonation of a large nuclear device. The accident in the Marshall Islands affords an example of large numbers of lesions of the skin in human beings from the fallout. Studies have been documented and will be referred to frequently in this chapter. The possibility of such accidents must be considered seriously in view of the increasingly widespread use of radioisotopes.

  19. Carborne fallout mapping - STUK/HUT team

    Energy Technology Data Exchange (ETDEWEB)

    Honkamaa, T.; Tiilikainen, H. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Aarnio, P.; Nikkinen, M. [Helsinki Univ. of Technology, Espoo (Finland)

    1997-12-31

    During the summer 1995 altogether 8,625 spectrometric and 3,108 dose-rate measurements were performed in Padasjoki Auttoinen village using carborne measuring devices. As a result {sup 137}Cs fallout and dose-rate maps were produced. The highest measured values in the test area II were 160 kBq m{sup -2} for fallout and 0.22 {mu}Sv h{sup -1} for dose-rate. One hot spot was found beside the test area (dose rate 0.31 {mu}Sv h{sup -1}). On the cultivated areas the measured count rates in {sup 137}Cs-window are three to four times lower than in the forest areas in average, indicating an altered depth profile of caesium. (au).

  20. A Probabilistic View of Debris Flow

    Institute of Scientific and Technical Information of China (English)

    LI Yong; SU Pengcheng; CUI Peng; HU Kaiheng

    2008-01-01

    Most debris flows occur in valleys of area smaller than 50 km2. While associated with a valley, debris flow is by no means a full-valley event but originates from parts of the valley, i.e., the tributary sources. We propose that debris flow develops by extending from tributaries to the mainstream. The debris flow observed in the mainstream is the confluence of the tributary flows and the process of the confluence can be considered as a combination of the tributary elements. The frequency distribution of tributaries is found subject to the Weibull form (or its generalizations). And the same distribution form applies to the discharge of debris flow. Then the process of debris flow is related to the geometric structure of the valley. Moreover, viewed from a large scale of water system, all valleys are tributaries, which have been found to assume the same distribution. With each valley corresponding to a debris flow, the distribution can be taken as the frequency distribution of debris flow and therefore provides a quantitative description of the fact that debris flow is inclined to occur at valley of small size. Furthermore, different parameters appear in different regions, suggesting the regional differentials of debris flow potential. We can use the failure rate, instead of the size per se, to describe the risk of a valley of a given area. Finally we claim that the valleys of debris flow in different regions are in the similar episode of evolution.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

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

    2016-04-01

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

  6. Radioactive Fallout from Terrorist Nuclear Detonations

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Chernobyl fallout and cancer incidence in Finland.

    Science.gov (United States)

    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 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. Atomic gas in debris discs

    Science.gov (United States)

    Hales, Antonio S.; Barlow, M. J.; Crawford, I. A.; Casassus, S.

    2017-04-01

    We have conducted a search for optical circumstellar absorption lines in the spectra of 16 debris disc host stars. None of the stars in our sample showed signs of emission line activity in either Hα, Ca II or Na I, confirming their more evolved nature. Four stars were found to exhibit narrow absorption features near the cores of the photospheric Ca II and Na I D lines (when Na I D data were available). We analyse the characteristics of these spectral features to determine whether they are of circumstellar or interstellar origins. The strongest evidence for circumstellar gas is seen in the spectrum of HD 110058, which is known to host a debris disc observed close to edge-on. This is consistent with a recent ALMA detection of molecular gas in this debris disc, which shows many similarities to the β Pictoris system.

  9. Frequent outburst floods from South Tahoma Glacier, Mount Rainier, USA: relation to debris flows, meteorological origin, and implications for subglacial hydrology

    Science.gov (United States)

    Walder, J.S.; Driedger, C.L.

    1995-01-01

    Destructive debris flows occur frequently at glacierized Mount Rainier volcano, Washington, USA. 23 such flows have occurred in the Tahoma Creek valley since 1967. Hydrologic and geomorphic evidence indicate that all or nearly all of these flows began as outburst floods from South Tahoma Glacier. Flood waters are stored subglacially. The volume of stored water discharged during a typical outburst flood would form a layer several centimeters thick over the bed of the entire glacier, although it is more likely that large linked cavities account for most of the storage. We suggest that outburst floods are triggered by rapid water input to the glacier bed, causing water-pressure transients that destabilize the linked-cavity system. -from Authors

  10. The physics of debris flows

    Science.gov (United States)

    Iverson, R.M.

    1997-01-01

    permeability of the debris. Realistic models of debris flows therefore require equations that simulate inertial motion of surges in which high-resistance fronts dominated by solid forces impede the motion of low-resistance tails more strongly influenced by fluid forces. Furthermore, because debris flows characteristically originate as nearly rigid sediment masses, transform at least partly to liquefied flows, and then transform again to nearly rigid deposits, acceptable models must simulate an evolution of material behavior without invoking preternatural changes in material properties. A simple model that satisfies most of these criteria uses depth-averaged equations of motion patterned after those of the Savage-Hutter theory for gravity-driven flow of dry granular masses but generalized to include the effects of viscous pore fluid with varying pressure. These equations can describe a spectrum of debris flow behaviors intermediate between those of wet rock avalanches and sediment-laden water floods. With appropriate pore pressure distributions the equations yield numerical solutions that successfully predict unsteady, nonuniform motion of experimental debris flows.

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

    Science.gov (United States)

    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.

  12. Characteristics, extent and origin of hydrothermal alteration at Mount Rainier Volcano, Cascades Arc, USA: Implications for debris-flow hazards and mineral deposits

    Science.gov (United States)

    John, D.A.; Sisson, T.W.; Breit, G.N.; Rye, R.O.; Vallance, J.W.

    2008-01-01

    Hydrothermal alteration at Mount Rainier waxed and waned over the 500,000-year episodic growth of the edifice. Hydrothermal minerals and their stable-isotope compositions in samples collected from outcrop and as clasts from Holocene debris-flow deposits identify three distinct hypogene argillic/advanced argillic hydrothermal environments: magmatic-hydrothermal, steam-heated, and magmatic steam (fumarolic), with minor superimposed supergene alteration. The 3.8??km3 Osceola Mudflow (5600??y BP) and coeval phreatomagmatic F tephra contain the highest temperature and most deeply formed hydrothermal minerals. Relatively deeply formed magmatic-hydrothermal alteration minerals and associations in clasts include quartz (residual silica), quartz-alunite, quartz-topaz, quartz-pyrophyllite, quartz-dickite/kaolinite, and quartz-illite (all with pyrite). Clasts of smectite-pyrite and steam-heated opal-alunite-kaolinite are also common in the Osceola Mudflow. In contrast, the Paradise lahar, formed by collapse of the summit or near-summit of the edifice at about the same time, contains only smectite-pyrite and near-surface steam-heated and fumarolic alteration minerals. Younger debris-flow deposits on the west side of the volcano (Round Pass and distal Electron Mudflows) contain only low-temperature smectite-pyrite assemblages, whereas the proximal Electron Mudflow and a temperatures. The pre-Osceola Mudflow alteration geometry is inferred to have consisted of a narrow feeder zone of intense magmatic-hydrothermal alteration limited to near the conduit of the volcano, which graded outward to more widely distributed, but weak, smectite-pyrite alteration within 1??km of the edifice axis, developed chiefly in porous breccias. The edifice was capped by a steam-heated alteration zone, most of which resulted from condensation of fumarolic vapor and oxidation of H2S in the unsaturated zone above the water table. Weakly developed smectite-pyrite alteration extended into the west and east

  13. Origins.

    Science.gov (United States)

    Online-Offline, 1999

    1999-01-01

    Provides an annotated list of resources dealing with the theme of origins of life, the universe, and traditions. Includes Web sites, videos, books, audio materials, and magazines with appropriate grade levels and/or subject disciplines indicated; professional resources; and learning activities. (LRW)

  14. Orbital Debris-Debris Collision Avoidance

    CERN Document Server

    Mason, James; Marshall, William; Levit, Creon

    2011-01-01

    We investigate the feasibility of using a medium-powered (5kW) ground-based laser combined with a ground-based telescope to prevent collisions between debris objects in low-Earth orbit (LEO), for which there is no current, effective mitigation strategy. The scheme utilizes photon pressure alone as a means to perturb the orbit of a debris object. Applied over multiple engagements, this alters the debris orbit sufficiently to reduce the risk of an upcoming conjunction. We employ standard assumptions for atmospheric conditions and the resulting beam propagation. Using case studies designed to represent the properties (e.g. area and mass) of the current debris population, we show that one could significantly reduce the risk of more than half of all debris-debris collisions using only one such laser/telescope facility. We speculate on whether this could mitigate the debris fragmentation rate such that it falls below the natural debris re-entry rate due to atmospheric drag, and thus whether continuous long-term ope...

  15. Reflectance Spectra of Space Debris in GEO

    Science.gov (United States)

    Schildknecht, T.; Vannanti, A.; Krag, H.; Erd, C.

    The space debris environment in the Geostationary Earth Orbit (GEO) region is mostly investigated by means of optical surveys. Such surveys revealed a considerable amount of debris in the size range of 10 centimeter to one meter. Some of these debris exhibit particularly high area-to-mass ratios as derived from the evolution of their orbits. In order to understand the nature and eventually the origin of these objects, observations allowing to derive physical characteristics like size, shape and material are required. Information on the shape and the attitude motion of a debris piece may be obtained by photometric light curves. The most promising technique to investigate the surface material properties is reflectance spectroscopy. This paper discusses preliminary results obtained from spectrometric observations of space debris in GEO. The observations were acquired at the 1-meter ESA Space Debris Telescope (ESASDT) on Tenerife with a low-resolution spectrograph in the wavelength range of 450-960 nm. The target objects were space debris of different types with brightness as small as magnitude 15. Some simple-shaped, intact "calibration objects" with known surface materials like the MSG-2 satellites were also observed. The spectra show shape variations expected to be caused by the different physical properties of the objects. The determination of the possible materials is still in a preliminary phase. Limitations of the acquisition process of the spectra and the subsequent analysis are discussed. Future steps planned for a better characterization of the debris from the observed data are briefly outlined.

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

    Science.gov (United States)

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

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

  17. Trees as Filters of Radioactive Fallout from the Chernobyl Accident

    CERN Document Server

    Brownridge, James D

    2011-01-01

    This paper is a copy of an unpublished study of the filtering effect of red maple trees (acer rubrum) on fission product fallout near Binghamton, NY, USA following the 1986 Chernobyl accident. The conclusions of this work may offer some insight into what is happening in the forests exposed to fallout from the Fukushima Daiichi Nuclear Plant accident. This posting is in memory of Noel K. Yeh.

  18. Origin and Distribution of the Post KPG Carbonate Debris Flow and Consequent Slope Readjustment in DeSoto Canyon, Gulf of Mexico

    Science.gov (United States)

    Umbarger, K.; Snedden, J.

    2015-12-01

    The induced seismicity from the Chicxulub impact crater has been postulated as thecatalyst for the dramatic alteration and movement of sediments in the Gulf of Mexico. Previousstudies have proposed the collapse of the continental margin in the Desoto Canyon region of theGulf of Mexico to be associated with the extraterrestrial impact, but provide limited evidence tosupport their claims. Seismic analysis of offshore two-dimensional (2D) seismic data, well logs,and biostratigraphic data provides insight into the Paleogene history of the carbonate marginslope failure and readjustment along the Florida escarpment. A slope's stability is dependent onthe slope material's shear strength, which resists slope failure, and the force of gravity, whichdrives slope failure. However, the slopes of carbonate platforms are seldom homogenous andreceive and lose sediment through the complex interplay of deposition, erosion, and dissolution.It is hypothesized the collapse of the Florida continental margin resulted in a layer of limestoneforming a steep slope due to its hardness producing a higher shear strength and angle of repose.When this is succeeded by the deposition of siliciclastic sediments a period of slope readjustmenttakes place. These finer and softer sediments are unable to assume the high slope angle of theunderlying carbonate sediments. This slope adjustment is continued throughout the Paleogene asthe out-of-grade slope of the Mass Transport Complex adjusts to reach equilibrium. The originand distribution of the post KPg carbonate debris flow in Desoto Canyon, Gulf of Mexico,elucidates the complexity of out-of-grade slopes readjusting to reach its ideal angle ofsedimentation.

  19. Debris of carbon-fibers originated from a CFRP (pEEK) wrist-plate triggered a destruent synovitis in human.

    Science.gov (United States)

    Merolli, Antonio; Rocchi, Lorenzo; De Spirito, Marco; Federico, Francesco; Morini, Alessandro; Mingarelli, Luigi; Fanfani, Francesco

    2016-03-01

    Application of carbon-fiber-reinforced-polymer (CFRP) artifacts in humans has been promoted in Orthopedic and Trauma Surgery. Literature documents the biocompatibility of materials used, namely carbon fibers (CF) and poly-ether thermoplastics, like poly-ether-ether-ketone (PEEK). A properly designed and accurately implanted composite artifact should not expose its fibers during or after surgery: however this may happen. A white Caucasian woman came to our attention 11 months after surgery for a wrist fracture. She had a severe impairment, being unable to flex the thumb; index finger and distal phalanx of third finger. We retrieved a correctly positioned plate and documented an aggressive erosive flexor tendons synovitis with eroded stumps of flexor tendons. The plate and soft tissues were analyzed by Visible Light and Scanning Electron Microscopy. Histopathology showed granulomatous fibrogenic process with CF engulfed inside multinucleated giant cells. Fibers were unmasked and disrupted inside the holes where screws were tightened and corrugation of the polymer coating led to further unmasking. The mechanism of foreign-body reaction to CF has not been studied in depth yet, particularly at the ultrastructural level and in Humans. This case documents a damage occurred in a clinical application and which was theoretically possible. Our opinion is that a proper way to promote the use of CRFP in the Clinic in the short term is to direct Research towards finding a better way to prevent CF debris to be exposed and released. In the longer term, the biological response to CF deserves a deeper understanding.

  20. Characteristics, extent and origin of hydrothermal alteration at Mount Rainier Volcano, Cascades Arc, USA: Implications for debris-flow hazards and mineral deposits

    Science.gov (United States)

    John, David A.; Sisson, Thomas W.; Breit, George N.; Rye, Robert O.; Vallance, James W.

    2008-08-01

    Hydrothermal alteration at Mount Rainier waxed and waned over the 500,000-year episodic growth of the edifice. Hydrothermal minerals and their stable-isotope compositions in samples collected from outcrop and as clasts from Holocene debris-flow deposits identify three distinct hypogene argillic/advanced argillic hydrothermal environments: magmatic-hydrothermal, steam-heated, and magmatic steam (fumarolic), with minor superimposed supergene alteration. The 3.8 km 3 Osceola Mudflow (5600 y BP) and coeval phreatomagmatic F tephra contain the highest temperature and most deeply formed hydrothermal minerals. Relatively deeply formed magmatic-hydrothermal alteration minerals and associations in clasts include quartz (residual silica), quartz-alunite, quartz-topaz, quartz-pyrophyllite, quartz-dickite/kaolinite, and quartz-illite (all with pyrite). Clasts of smectite-pyrite and steam-heated opal-alunite-kaolinite are also common in the Osceola Mudflow. In contrast, the Paradise lahar, formed by collapse of the summit or near-summit of the edifice at about the same time, contains only smectite-pyrite and near-surface steam-heated and fumarolic alteration minerals. Younger debris-flow deposits on the west side of the volcano (Round Pass and distal Electron Mudflows) contain only low-temperature smectite-pyrite assemblages, whereas the proximal Electron Mudflow and a < 100 y BP rock avalanche on Tahoma Glacier also contain magmatic-hydrothermal alteration minerals that are exposed in the avalanche headwall of Sunset Amphitheater, reflecting progressive incision into deeper near-conduit alteration products that formed at higher temperatures. The pre-Osceola Mudflow alteration geometry is inferred to have consisted of a narrow feeder zone of intense magmatic-hydrothermal alteration limited to near the conduit of the volcano, which graded outward to more widely distributed, but weak, smectite-pyrite alteration within 1 km of the edifice axis, developed chiefly in porous breccias

  1. Neogene fallout tuffs from the Yellowstone hotspot in the Columbia Plateau region, Oregon, Washington and Idaho, USA.

    Directory of Open Access Journals (Sweden)

    Barbara P Nash

    Full Text Available 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.

  2. Neogene fallout tuffs from the Yellowstone hotspot in the Columbia Plateau region, Oregon, Washington and Idaho, USA.

    Science.gov (United States)

    Nash, Barbara P; Perkins, Michael E

    2012-01-01

    Sedimentary sequences in the Columbia Plateau region of the Pacific Northwest ranging in age from 16-4 Ma contain fallout tuffs whose origins lie in volcanic centers of the Yellowstone hotspot in northwestern Nevada, eastern Oregon and the Snake River Plain in Idaho. Silicic volcanism began in the region contemporaneously with early eruptions of the Columbia River Basalt Group (CRBG), and the abundance of widespread fallout tuffs provides the opportunity to establish a tephrostratigrahic framework for the region. Sedimentary basins with volcaniclastic deposits also contain diverse assemblages of fauna and flora that were preserved during the Mid-Miocene Climatic Optimum, including Sucker Creek, Mascall, Latah, Virgin Valley and Trout Creek. Correlation of ashfall units establish that the lower Bully Creek Formation in eastern Oregon is contemporaneous with the Virgin Valley Formation, the Sucker Creek Formation, Oregon and Idaho, Trout Creek Formation, Oregon, and the Latah Formation in the Clearwater Embayment in Washington and Idaho. In addition, it can be established that the Trout Creek flora are younger than the Mascall and Latah flora. A tentative correlation of a fallout tuff from the Clarkia fossil beds, Idaho, with a pumice bed in the Bully Creek Formation places the remarkably well preserved Clarkia flora assemblage between the Mascall and Trout Creek flora. Large-volume supereruptions that originated between 11.8 and 10.1 Ma from the Bruneau-Jarbidge and Twin Falls volcanic centers of the Yellowstone hotspot in the central Snake River Plain deposited voluminous fallout tuffs in the Ellensberg Formation which forms sedimentary interbeds in the CRBG. These occurrences extend the known distribution of these fallout tuffs 500 km to the northwest of their source in the Snake River Plain. Heretofore, the distal products of these large eruptions had only been recognized to the east of their sources in the High Plains of Nebraska and Kansas.

  3. Tracing the Iodine-129 fallout in Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Niello, Jorge; Negri, Agustin; Arazi, Andres [Comision Nacional de Energia Atomica (CNEA), Buenos Aires (Argentina). Lab. TANDAR; Wallner, Anton [The Australian National University, Canberra (Australia). Dept. of Nuclear Physics; Niello, Jorge Fernandez [Universidad Nacional de San Martin, Campus Miguelete, Buenos Aires (Argentina)

    2012-07-01

    Full text: Long-lived {sup 129}I (half-life=15.6 Ma) is produced naturally by irradiation of atmospheric xenon by cosmic neutrons and in the sub-surface by spontaneous fission of {sup 238}U, from which the natural inventory of {sup 129}I has been estimated to be around 50,000 kg, only 140 kg of them corresponds to the hydrospheric inventory. Nuclear tests and accidents have added between 45-130 kg. Apart from a global atmospheric fallout component, {sup 129}I has been released from several nuclear fuel reprocessing plants located in the Northern Hemisphere (ca. 6000 kg) which serve as localized sources in oceanographic-tracer experiments. In this presentation, we report results from a study exploring the presence of {sup 129}I in the Southern Hemisphere by determining {sup 129}I/{sup 127}I isotopic ratios in water samples (rivers, lakes and shallow sea-water) taken at different latitudes in Argentina including Antarctica. The iodine-127 and iodine-129 concentrations were measured via ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and Accelerator Mass Spectrometry (AMS), respectively. Distribution of both isotopes can be understood considering tropospheric circulation patterns, possible sources and regional precipitation patterns. Natural and anthropogenic sources for the Southern Hemisphere and their inventories are discussed. Similar contribution came from natural sources and nuclear tests. Contribution from the nuclear fuel reprocessing plants placed in the Northern hemisphere can be neglected. (author)

  4. 泥石流源区弱固结砾石土的渗透规律%The Research of Permeability on Lose Gravelly Soil in Debris Flow Original Area

    Institute of Scientific and Technical Information of China (English)

    陈宁生; 张军

    2001-01-01

    Choose the debris flow original area, on loose gravelly soilslope, to do permeability experiment. The experiment area is 4000cm2. The Shower nozzle is used to produce rains. The precipitation is controlled by block up some of the hole on shower nozzle. Therefore, the infiltration rate is gotten. It is found that the rate of stable infiltration is 0.11 mm/min. The initial infiltration is 0.55 mm/min. From the test data the value of β is obtained,β=0.56.Therefore, the permeability formula be written as Fp=0.11+0.44e-0.56t This rormula can be used to calculate the runoff resulted from excess rain in debris flow original area. The ratio of the amount of runoff to that of debris flow can be obtained. In terms of the raining processes of Dawazi gully between 0~12 o'clock on June 15~16,1994,the runoff resulted from excess rain is gotten. It is found that the rate of runoff is 0.415 mm/min. This value take17.8% of the total discharge of debris flow.%泥石流源区砾石土的渗透过程是泥石流形成全过程中不可缺少的一个子过程,该研究对泥石流形成规律的认识和对泥石流汇流计算具有重要的意义。为此,笔者与日本学者一道选择蒋家沟支沟——大凹子沟的弱固结坡积物坡面做径流产流实验,实验区面积4000cm2,实验用可控的头降雨,通过接收和量取超渗产流的量,判断土体是否达到稳定下渗,得出初始下渗率为0.55mm/min,参数β为0.56。通过下渗率与时间关系的曲线描述,建立泥石流源区砾石土的渗透方程,该方程可用物分析泥石流源区激发雨量过程的渗透规律,同时揭示泥石流源区产流过程地表径流的形成机理及其与流体的产生及流量的关系。通过大凹子沟1994-06-15~16日的降雨资料可计算出超渗产流为0.415mm/min,其总流量占泥石流总流量的17.8%。

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

    Science.gov (United States)

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

    2015-07-01

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

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

    Science.gov (United States)

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

    2015-07-17

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

  7. Remote sensing and characterization of anomalous debris

    Science.gov (United States)

    Sridharan, R.; Beavers, W.; Lambour, R.; Gaposchkin, E. M.; Kansky, J.; Stansbery, E.

    1997-01-01

    The analysis of orbital debris data shows a band of anomalously high debris concentration in the altitude range between 800 and 1000 km. Analysis indicates that the origin is the leaking coolant fluid from nuclear power sources that powered a now defunct Soviet space-based series of ocean surveillance satellites. A project carried out to detect, track and characterize a sample of the anomalous debris is reported. The nature of the size and shape of the sample set, and the possibility of inferring the composition of the droplets were assessed. The technique used to detect, track and characterize the sample set is described and the results of the characterization analysis are presented. It is concluded that the nature of the debris is consistent with leaked Na-K fluid, although this cannot be proved with the remote sensing techniques used.

  8. Molecular Gas in Young Debris Disks

    Science.gov (United States)

    Moór, Attila; Kóspál, Ágnes; Ábrahám, Péter; Juhász, Attila; Apai, Dániel; Csengeri, Timea; Grady, Carol; Henning, Thomas; Kiss, Csaba; Pascucci, Ilaria

    2013-07-01

    Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. So far only a very few debris disks with measurable gas component have been known. We carried out a survey with the APEX radio telescope to detect molecular gas at millimeter wavelengths in 28 infrared-luminous young debris disks, and discovered two new systems with substantial amount of CO. Motivated to understand the origin, physics, and evolutionary status of the gas in these systems we observed one of them, HD 21997, with ALMA and Herschel. Our results suggest that HD 21997 may be a hybrid system where secondary debris dust and residual primordial gas coexist. This poses a serious question to the current paradigm, since the age of the system (30 Myr) significantly exceeds model predictions for disk clearing and the ages of the oldest transitional disks.

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

    Science.gov (United States)

    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. Debris flow, debris avalanche and flood hazards at and downstream from Mount Rainier, Washington

    Science.gov (United States)

    Scott, Kevin M.; Vallance, J.W.

    1995-01-01

    Mount Rainier volcano has produced many large debris flows and debris avalanches during the last 10,000 years. These flows have periodically traveled more than 100 kilometers from the volcano to inundate parts of the now-populated Puget Sound Lowland. Meteorological floods also have caused damage, but future effects will be partly mitigated by reservoirs. Mount Rainier presents the most severe flow risks of any volcano in the United States. Volcanic debris flows (lahars) are of two types: (1) cohesive, relatively high clay flows originating as debris avalanches, and (2) noncohesive flows with less clay that begin most commonly as meltwater surges. Three case histories represent important subpopulations of flows with known magnitudes and frequencies. The risks of each subpopulation may be considered for general planning and design. A regional map illustrates the extent of inundation by the case-history flows, the largest of which originated as debris avalanches and moved from Mount Rainier to Puget Sound. The paleohydrologic record of these past flows indicates the potential for inundation by future flows from the volcano. A map of the volcano and its immediate vicinity shows examples of smaller debris avalanches and debris flows in the 20th century.

  11. Local fall-out and the animal food chain; Retombees locales et chaine alimentaire animale

    Energy Technology Data Exchange (ETDEWEB)

    Prat, G.; Mercier, F.J. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1967-07-01

    The local consequences of fresh fall-out, especially in the case of atmospheric nuclear explosions, are reviewed from the point of view of the internal contamination of the consumer of foodstuffs of animal origin. The edibility of foodstuffs derived from animals having grazed in the presence of fall-out is evaluated both from the wholesome and radio-toxicological points of view. The contamination level of these foodstuffs is calculated as a function of the ground fall-out, and of agronomical and ecological parameters for each radio-nuclide of the animal food chain. The internal exposure of the human consumer is calculated from this level as a function of the diet and of various parameters especially temporal. The equivalent dose to each critical organ, including the digestive tract is deduced from the burdens of each organ. From this a nutritional hygiene in the areas affected by fall-out is obtained, in relationship to the action levels fixed by the responsible authorities in exceptional circumstances. Criteria for these action levels are given as function of the food rations. (authors) [French] Les consequences locales des retombees fraiches, notamment dans le cas d'explosions nucleaires atmospheriques, sont passees en revue en ce qui concerne les problemes de contamination interne du consommateur de denrees d'origine animale. La comestibilite des aliments provenant de betes de boucherie ayant pature sous les retombees est evaluee au double point de vue de la salubrite et de la radiotoxicologie. Le niveau de contamination de ces denrees est calcule en fonction de la retombee au sol, des parametres agronomiques et ecologiques pour chaque radioelement de la chaine alimentaire animale. La contamination interne du consommateur humain est calculee a partir de ce niveau en fonction des modalites d'ingestion et de divers parametres, notamment temporels. L'equivalent de dose au niveau de chaque organe critique, y compris le tube digestif, est deduit

  12. Debris mitigation techniques for petawatt-class lasers in high debris environments

    Directory of Open Access Journals (Sweden)

    Jens Schwarz

    2010-04-01

    Full Text Available This paper addresses debris mitigation techniques for two different kinds of debris sources that are found in the high-energy density community. The first debris source stems from the laser-target interaction and this debris can be mitigated by avoiding a direct line of sight to the debris source (e.g. by using a sacrificial fold mirror or by inserting a thin debris shield. Several thin film debris shields have been investigated and nitrocellulose was found to be the best suited. The second debris source originates from an external high-energy density driver or experiment. In our specific case, this is the Z accelerator, a Z-pinch machine that generates 2 MJ of x rays at 300 TW. The center section of the Z accelerator is an extremely violent environment which requires the development of novel debris mitigation approaches for backlighting with petawatt lasers. Two such approaches are presented in this paper. First, a self-closing focusing cone. In our facility, the focused beam on target is fully enclosed inside a solid focusing cone. In the first debris mitigation scenario, the last part of the cone has a “flapper” that should seal the cone when the pressure wave from the Z-pinch explosion hits it. In the second scenario, an enclosed target assembly is used, with the last part of the focusing cone connected to a “target can” which houses the laser target. The laser produced x rays for backlighting escape through a 3 mm diameter hole that is protected by an x-ray filter stack. Both techniques are discussed in detail and have been successfully tested on the Z accelerator.

  13. Modeling debris-covered glaciers: response to steady debris deposition

    Science.gov (United States)

    Anderson, Leif S.; Anderson, Robert S.

    2016-05-01

    Debris-covered glaciers are common in rapidly eroding alpine landscapes. When thicker than a few centimeters, surface debris suppresses melt rates. If continuous debris cover is present, ablation rates can be significantly reduced leading to increases in glacier length. In order to quantify feedbacks in the debris-glacier-climate system, we developed a 2-D long-valley numerical glacier model that includes englacial and supraglacial debris advection. We ran 120 simulations on a linear bed profile in which a hypothetical steady state debris-free glacier responds to a step increase of surface debris deposition. Simulated glaciers advance to steady states in which ice accumulation equals ice ablation, and debris input equals debris loss from the glacier terminus. Our model and parameter selections can produce 2-fold increases in glacier length. Debris flux onto the glacier and the relationship between debris thickness and melt rate strongly control glacier length. Debris deposited near the equilibrium-line altitude, where ice discharge is high, results in the greatest glacier extension when other debris-related variables are held constant. Debris deposited near the equilibrium-line altitude re-emerges high in the ablation zone and therefore impacts melt rate over a greater fraction of the glacier surface. Continuous debris cover reduces ice discharge gradients, ice thickness gradients, and velocity gradients relative to initial debris-free glaciers. Debris-forced glacier extension decreases the ratio of accumulation zone to total glacier area (AAR). Our simulations reproduce the "general trends" between debris cover, AARs, and glacier surface velocity patterns from modern debris-covered glaciers. We provide a quantitative, theoretical foundation to interpret the effect of debris cover on the moraine record, and to assess the effects of climate change on debris-covered glaciers.

  14. Strategy for mitigation of marine debris: analysis of sources and composition of marine debris in northern Taiwan.

    Science.gov (United States)

    Kuo, Fan-Jun; Huang, Hsiang-Wen

    2014-06-15

    Six sites (two sites for each of rocky shores, sandy beaches, and fishing ports) in northern Taiwan were selected to investigate the amount and density of marine debris in each of the four seasons and after spring and neap tides from 2012 to 2013. The results indicate that marine debris was higher on rocky shores than sandy beaches and fishing ports. There is no significant difference between season and tide. The dominant debris was plastic-type, followed by polystyrene. The majority of debris originated from recreational activities, followed from ocean/waterway activities. The results suggest that the following actions are needed: (1) continue and reinforce the plastic-limit policy; (2) increase the cleaning frequency at rocky shores; (3) promote marine environmental education, with a goal of debris-free coasts; (4) recycle fishing gear and to turn that gear into energy; and (5) coordinate between agencies to establish a mechanism to monitor debris.

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

    Science.gov (United States)

    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.

  16. Temporal trends in childhood leukaemia incidence following exposure to radioactive fallout from atmospheric nuclear weapons testing.

    Science.gov (United States)

    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

  17. Medical status of Marshallese accidentally exposed to 1954 Bravo fallout radiation: January 1980-December 1982

    Energy Technology Data Exchange (ETDEWEB)

    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)

  18. Special Report Debris - Race

    Data.gov (United States)

    U.S. Environmental Protection Agency — Marine debris degrades ocean habitats, endangers marine and coastal wildlife, causes navigation hazards, results in economic losses to industry and governments, and...

  19. Disaster Debris Recovery Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — The US EPA Region 5 Disaster Debris Recovery Database includes public datasets of over 3,500 composting facilities, demolition contractors, haulers, transfer...

  20. Planetesimals in Debris Disks

    CERN Document Server

    Youdin, Andrew N

    2015-01-01

    Planetesimals form in gas-rich protoplanetary disks around young stars. However, protoplanetary disks fade in about 10 Myr. The planetesimals (and also many of the planets) left behind are too dim to study directly. Fortunately, collisions between planetesimals produce dusty debris disks. These debris disks trace the processes of terrestrial planet formation for 100 Myr and of exoplanetary system evolution out to 10 Gyr. This chapter begins with a summary of planetesimal formation as a prelude to the epoch of planetesimal destruction. Our review of debris disks covers the key issues, including dust production and dynamics, needed to understand the observations. Our discussion of extrasolar debris keeps an eye on similarities to and differences from Solar System dust.

  1. Roll Call Debris - Race

    Data.gov (United States)

    U.S. Environmental Protection Agency — Marine debris degrades ocean habitats, endangers marine and coastal wildlife, causes navigation hazards, results in economic losses to industry and governments, and...

  2. LEGACY - EOP Marine Debris

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data contains towed diver surveys of and weights of marine debris removed from the near shore environments of the NWHI.

  3. Fleet Debris Levels

    Data.gov (United States)

    U.S. Environmental Protection Agency — Marine debris degrades ocean habitats, endangers marine and coastal wildlife, causes navigation hazards, results in economic losses to industry and governments, and...

  4. Characterization of Debris from the DebriSat Hypervelocity Test

    Science.gov (United States)

    Rivero, M.; Kleespies, J.; Patankar, K.; Fitz-Coy, N.; Liou, J.-C.; Sorge, M.; Huynh, T.; Opiela, J.; Krisko, P.; Cowardin, H.

    2015-01-01

    The DebriSat project is an effort by NASA and the DoD to update the standard break-up model for objects in orbit. The DebriSat object, a 56 kg representative LEO satellite, was subjected to a hypervelocity impact in April 2014. For the hypervelocity test, the representative satellite was suspended within a "soft-catch" arena formed by polyurethane foam panels to minimize the interactions between the debris generated from the hypervelocity impact and the metallic walls of the test chamber. After the impact, the foam panels and debris not caught by the panels were collected and shipped to the University of Florida where the project has now advanced to the debris characterization stage. The characterization effort has been divided into debris collection, measurement, and cataloguing. Debris collection and cataloguing involves the retrieval of debris from the foam panels and cataloguing the debris in a database. Debris collection is a three-step process: removal of loose debris fragments from the surface of the foam panels; X-ray imaging to identify/locate debris fragments embedded within the foam panel; extraction of the embedded debris fragments identified during the X-ray imaging process. As debris fragments are collected, they are catalogued into a database specifically designed for this project. Measurement involves determination of size, mass, shape, material, and other physical properties and well as images of the fragment. Cataloguing involves a assigning a unique identifier for each fragment along with the characterization information.

  5. Topographic Effects on Ambient Dose Equivalent Rates from Radiocesium Fallout

    CERN Document Server

    Malins, Alex; Machida, Masahiko; Saito, Kimiaki

    2015-01-01

    Land topography can affect air radiation dose rates by locating radiation sources closer to, or further, from detector locations when compared to perfectly flat terrain. Hills and slopes can also shield against the propagation of gamma rays. To understand the possible magnitude of topographic effects on air dose rates, this study presents calculations for ambient dose equivalent rates at a range of heights above the ground for varying land topographies. The geometries considered were angled ground at the intersection of two planar surfaces, which is a model for slopes neighboring flat land, and a simple conical geometry, representing settings from hilltops to valley bottoms. In each case the radiation source was radioactive cesium fallout, and the slope angle was varied systematically to determine the effect of topography on the air dose rate. Under the assumption of homogeneous fallout across the land surface, and for these geometries and detector locations, the dose rates at high altitudes are more strongly...

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

    Science.gov (United States)

    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.

  7. Space Debris & its Mitigation

    Science.gov (United States)

    Kaushal, Sourabh; Arora, Nishant

    2012-07-01

    Space debris has become a growing concern in recent years, since collisions at orbital velocities can be highly damaging to functioning satellites and can also produce even more space debris in the process. Some spacecraft, like the International Space Station, are now armored to deal with this hazard but armor and mitigation measures can be prohibitively costly when trying to protect satellites or human spaceflight vehicles like the shuttle. This paper describes the current orbital debris environment, outline its main sources, and identify mitigation measures to reduce orbital debris growth by controlling these sources. We studied the literature on the topic Space Debris. We have proposed some methods to solve this problem of space debris. We have also highlighted the shortcomings of already proposed methods by space experts and we have proposed some modification in those methods. Some of them can be very effective in the process of mitigation of space debris, but some of them need some modification. Recently proposed methods by space experts are maneuver, shielding of space elevator with the foil, vaporizing or redirecting of space debris back to earth with the help of laser, use of aerogel as a protective layer, construction of large junkyards around international space station, use of electrodynamics tether & the latest method proposed is the use of nano satellites in the clearing of the space debris. Limitations of the already proposed methods are as follows: - Maneuvering can't be the final solution to our problem as it is the act of self-defence. - Shielding can't be done on the parts like solar panels and optical devices. - Vaporizing or redirecting of space debris can affect the human life on earth if it is not done in proper manner. - Aerogel has a threshold limit up to which it can bear (resist) the impact of collision. - Large junkyards can be effective only for large sized debris. In this paper we propose: A. The Use of Nano Tubes by creating a mesh

  8. In-situ measurements of the radioactive fallout deposit

    Science.gov (United States)

    Korun, M.; Martinčič, R.; Pucelj, B.

    1991-02-01

    An improved method to determine radionuclide concentrations in soil and the radioactive fallout deposit is presented. The approach is based on in-situ gamma-ray spectrometric measurements performed with a portable high resolution gamma spectrometer and on calculations of the depth distribution based on the energy dependence of the attenuation of gamma rays in soil. The results are compared with laboratory analysis of collected soil samples.

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

    Science.gov (United States)

    1957-10-01

    also equipped with gummed paper collectors (GPC). In addition, on Shot Boltzmann, resin coated plates (RCP), the LASL Model, were added "to twenty...samples at the same location while resin- coated plates yielded values considerably lower than the GC. • • 81V( , * .....- I • ’ r sr" ’ ,, i -rvi.. • •’Y...mixture of paraffin and beeswax . This step 242 immobilized fallout material on the pelt and minimized contamination from the fur during further

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

    Science.gov (United States)

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

    1964-02-28

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

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

    Science.gov (United States)

    2012-09-01

    difficulty of making accurate fallout predictions. 2.2.1 Fireball In the first few instants following a nuclear explosion, fireball temperatures can...exceed 107 K, and the resulting gradient between the atmospheric and the fireball temperatures will cause the fireball to rise [2]. The temperature...will decrease initially through radiative cooling, but as toroidal motion of the fireball begins to dominate, entrainment of cold air will result in

  12. Source Normalization Constants for Ground Distributed Fallout Fields

    Science.gov (United States)

    2011-09-01

    normalization constant ( SNC ). The effects of time on the SNC are also examined by the ORIGEN Fallout Analysis Tool in order to determine if a separate time...25% increase to the first order model SNC . The effects of non- uniform activity density are found to be insignificant; however, the effects of time...on the SNC are found to warrant an additional time correction factor. In summarizing Herte’s results, terrain roughness is shown to produce between

  13. Web-Enabled Optoelectronic Particle-Fallout Monitor

    Science.gov (United States)

    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.

  14. Cs-137 fallout in Iceland, model predictions and measurements

    Energy Technology Data Exchange (ETDEWEB)

    Palsson, S.E.; Sigurgeirsson, M.A.; Gudnason, K. [Icelandic Radiation Protection Inst. (Iceland); Arnalds, O.; Karlsdottir, I.A. [Agricultural Research Inst. (Iceland); Palsdottir, P. [Icelandic Meteorological Office (Iceland)

    2002-04-01

    Basically all the fallout Cs-137 in Iceland came from the atmospheric nuclear weapons tests in the late fifties and early sixties, the addition from the accident in the Chernobyl Nuclear Power Plant was relatively very small. Measurements of fallout from nuclear weapons tests started in Iceland over 40 years ago and samples of soil, vegetation and agricultural products have been collected from various places and measured during this period. Considerable variability has been seen in the results, even between places close to each other. This is understandable due to the mountainous terrain, changing strong winds and high levels of precipitation. This variability has been especially noticeable in the case of soil samples. The important role of uncultivated rangelands in Icelandic agriculture (e.g. for sheep farming) makes it necessary to estimate deposition for many remote areas. It has thus proven difficult to get a good overview of the distribution of the deposition and its subsequent transfer into agricultural products. Over a year ago an attempt was made to assess the distribution of Cs-137 fallout in Iceland. The approach is based on a model predicting deposition using precipitation data, in a similar manner as that used previously within the Arctic Monitoring and Assessment Programme (AMAP). 1999). One station close to Reykjavik has a time series of Cs-137 deposition data and precipitation data from 1960 onwards. The AMAP deposition model was calibrated for Iceland by using deposition and precipitation data from this station. (au)

  15. Space Debris Mitigation Guidelines

    Science.gov (United States)

    Johnson, Nicholas L.

    2011-01-01

    The purpose of national and international space debris mitigation guides is to promote the preservation of near-Earth space for applications and exploration missions far into the future. To accomplish this objective, the accumulation of objects, particularly in long-lived orbits, must be eliminated or curtailed.

  16. Control method of dioxines and furans fallout around a UIOM; Methode de surveillance des retombees des dioxines et furanes autour d'une UIOM

    Energy Technology Data Exchange (ETDEWEB)

    Durif, M.

    2001-12-15

    This report presents the different methods used to evaluate the pollution related to the dioxines and the furans around an emitted source. Based on the advantages and disadvantages of each methods, a protocol is decided to realize a state of the art around a future implementation site of a unit of domestic wastes incineration (UIOM). This protocol will also be able to control and identify the origins of the fallout around the installation when it will operate. (A.L.B.)

  17. GIS-based numerical simulations of the July 2014 Nagiso debris flow in Nagano Prefecture, Japan

    Science.gov (United States)

    Wang, Chunxiang; Fukuoka, Hiroshi

    2015-04-01

    A debris flow disaster took place in Nagiso, Nagano Prefecture of Japan in the later afternoon of 9 July 2014 triggered by 76 mm torrential rain associated with the typhoon Neoguri. This debris flow killed one resident and completely destroyed several houses. Although the source of the debris flows, especially the origin of their large boulders exceeding 5 m, are not clear, it seems that those debris flows initiated in the two upstream torrents and they joined Nashisawa torrent. Finally the debris flow ran and deposited in the Kiso River. The downstream residents are much aware of the many historical cases on similar debris flow disasters in the torrents in Nagiso and surrounding communities. Most of the residents could evacuate immediately after they felt the ground tremors induced by the running debris flow. Authors used LAHARZ (Schilling 1998) to simulate the Nagiso debris flow using 5-meter resolution Digital Elevation Model and several debris-flow volumes for the calibration. We also performed a numerical simulation to predicting the runout distance and to get insight into the behavior of the debris flow movement. A GIS-based depth-averaged 2D numerical model using a coupled viscous and Coulomb type law is used to simulate a debris flow from initiation to deposition. We compared the two simulation results and suggested the more appropriate coefficients of equations in LAHARZ for calculating the cross sectional area and planimetric area for application to the July 2014 Nagiso debris flows.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

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

  1. Sources, composition and spatial distribution of marine debris along the Mediterranean coast of Israel

    Science.gov (United States)

    Pasternak, Galia; Zviely, Dov; Ribic, Christine; Ariel, Asaf; Spanier, Ehud

    2017-01-01

    Marine debris (litter) is a complex problem that affects human activities and the marine environment worldwide. The Clean Coast Program in Israel has had some success in keeping most of the coasts clean most of the time, but without understanding the mechanisms of accumulation of marine debris on the coasts of Israel. In 2012, we initiated a study to characterize the types of marine debris, its origins and spatial distribution. Nineteen surveys were done from June 2012 to March 2015 on eight beaches that spanned the coast of Israel. Average debris density was 12.1 items per 100 m2 and 90% of the items were plastic. The top debris categories were food wrappers and disposables, plastic bags and cigarette butts. However, there was variation in the top debris categories among the beaches indicating that a flexible approach with multiple options will be important when addressing the marine debris problem.

  2. Sources, composition and spatial distribution of marine debris along the Mediterranean coast of Israel.

    Science.gov (United States)

    Pasternak, Galia; Zviely, Dov; Ribic, Christine A; Ariel, Asaf; Spanier, Ehud

    2017-01-30

    Marine debris (litter) is a complex problem that affects human activities and the marine environment worldwide. The Clean Coast Program in Israel has had some success in keeping most of the coasts clean most of the time, but without understanding the mechanisms of accumulation of marine debris on the coasts of Israel. In 2012, we initiated a study to characterize the types of marine debris, its origins and spatial distribution. Nineteen surveys were done from June 2012 to March 2015 on eight beaches that spanned the coast of Israel. Average debris density was 12.1 items per 100m(2) and 90% of the items were plastic. The top debris categories were food wrappers and disposables, plastic bags and cigarette butts. However, there was variation in the top debris categories among the beaches indicating that a flexible approach with multiple options will be important when addressing the marine debris problem. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  4. Pollen fall-out from a tropical vegetation mosaic.

    Science.gov (United States)

    Walker; Sun

    2000-07-01

    Pollen fall-out into 60 Oldfield traps set in 11 localities and a variety of vegetational contexts on an upland in tropical northeast Australia, range from 0.5k to 20k (mean 3.5k)grcm(-2)a(-1). The ranges attributable to the four major vegetation types in which the traps were situated overlap to such an extent as would make it virtually impossible to allocate an 'unknown' pollen count to a vegetation type on the basis of total pollen influx alone. Nevertheless, the composition of the pollen clearly differs according to the vegetation in which it is trapped and the amounts of other vegetation types within at least 100m. Substantial variations in catches from closely placed traps suggest the influence of very local site, including meteorological, conditions on the results. Pollen is carried between vegetation types, much less far from rainforest than from sclerophyll forest and woodland, regrowth scrub or herbaceous vegetation, but there is no numerically significant ubiquitous 'background' fall-out in the region. The data impose some constraints on the interpretation of fossil pollen spectra but also potentially permit a greater precision in some aspects of such applications.

  5. Orbital debris issues

    Science.gov (United States)

    Kessler, D. J.

    Orbital debris issues fall into three major topics: Environment Definition, Spacecraft Hazard, and Space Object Management. The major issue under Environment Definition is defining the debris flux for sizes smaller (10 cm in diameter) than those tracked by the North American Aerospace Defense Command (NORAD). Sources for this size debris are fragmentation of larger objects, either by explosion or collision, and solid rocket motor products. Modeling of these sources can predict fluxes in low Earth orbit which are greater than the meteoroid environment. Techniques to measure the environment in the size interval between 1 mm and 10 cm are being developed, including the use of telescopes and radar both on the ground and in space. Some impact sensors designed to detect meteoroids may have detected solid rocket motor products. Once the environment is defined, it can be combined with hypervelocity impact data and damage criteria to evaluate the Spacecraft Hazard. Shielding may be required to obtain an acceptable damage level. Space Object Management includes techniques to control the environment and the desired policy to effectively minimize the hazard to spacecraft. One control technique - reducing the likelihood of future explosions in space - has already been implemented by NASA. The effectiveness of other techniques has yet to be evaluated.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, Michael B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kane, Staci R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    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.

  7. ORDEM2010 and MASTER-2009 Modeled Small Debris Population Comparison

    Science.gov (United States)

    Krisko, Paula H.; Flegel, S.

    2010-01-01

    The latest versions of the two premier orbital debris engineering models, NASA s ORDEM2010 and ESA s MASTER-2009, have been publicly released. Both models have gone through significant advancements since inception, and now represent the state-of-the-art in orbital debris knowledge of their respective agencies. The purpose of these models is to provide satellite designers/operators and debris researchers with reliable estimates of the artificial debris environment in near-Earth orbit. The small debris environment within the size range of 1 mm to 1 cm is of particular interest to both human and robotic spacecraft programs. These objects are much more numerous than larger trackable debris but are still large enough to cause significant, if not catastrophic, damage to spacecraft upon impact. They are also small enough to elude routine detection by existing observation systems (radar and telescope). Without reliable detection the modeling of these populations has always coupled theoretical origins with supporting observational data in different degrees. This paper details the 1 mm to 1 cm orbital debris populations of both ORDEM2010 and MASTER-2009; their sources (both known and presumed), current supporting data and theory, and methods of population analysis. Fluxes on spacecraft for chosen orbits are also presented and discussed within the context of each model.

  8. Modelling the fate of marine debris along a complex shoreline: Lessons from the Great Barrier Reef

    Science.gov (United States)

    Critchell, K.; Grech, A.; Schlaefer, J.; Andutta, F. P.; Lambrechts, J.; Wolanski, E.; Hamann, M.

    2015-12-01

    The accumulation of floating anthropogenic debris in marine and coastal areas has environmental, economic, aesthetic, and human health impacts. Until now, modelling the transport of such debris has largely been restricted to the large-scales of open seas. We used oceanographic modelling to identify potential sites of debris accumulation along a rugged coastline with headlands, islands, rocky coasts and beaches. Our study site was the Great Barrier Reef World Heritage Area that has an emerging problem with debris accumulation. We found that the classical techniques of modelling the transport of floating debris models are only moderately successful due to a number of unknowns or assumptions, such as the value of the wind drift coefficient, the variability of the oceanic forcing and of the wind, the resuspension of some floating debris by waves, and the poorly known relative contribution of floating debris from urban rivers and commercial and recreational shipping. Nevertheless the model was successful in reproducing a number of observations such as the existence of hot spots of accumulation. The orientation of beaches to the prevailing wind direction affected the accumulation rate of debris. The wind drift coefficient and the exact timing of the release of the debris at sea affected little the movement of debris originating from rivers but it affected measurably that of debris originating from ships. It was thus possible to produce local hotspot maps for floating debris, especially those originating from rivers. Such modelling can be used to inform local management decisions, and it also identifies likely priority research areas to more reliably predict the trajectory and landing points of floating debris.

  9. DEBRIS FLOWS AND HYPERCONCENTRATED STREAMFLOWS.

    Science.gov (United States)

    Wieczorek, Gerald F.

    1986-01-01

    Examination of recent debris-flow and hyperconcentrated-streamflow events in the western United States reveals (1) the topographic, geologic, hydrologic, and vegetative conditions that affect initiation of debris flows and (2) the wide ranging climatic conditions that can trigger debris flows. Recognition of these physiographic and climatic conditions has aided development of preliminary methods for hazard evaluation. Recent developments in the application of electronic data gathering, transmitting, and processing systems shows potential for real-time hazard warning.

  10. Mineralogical Evolution in Extreme Debris Disks

    Science.gov (United States)

    Su, Kate

    2015-10-01

    Young (10-200 Myr), luminous (fractional luminosity on the order of 1.E-2) extreme debris disks provide a unique opportunity to explore exo-asteriod and exo-planetesimal collisions during the oligarchic and chaotic phases of terrestrial planet-building. We propose to obtain low-resolution grism spectra of four extreme debris disks to document and characterize the mineralogy changes in the mid-IR region where strong peaks originating from silica and forsterite dust can be easily identified. The proposed observations will supplement our on-going warm Spitzer monitoring program studying disk variability at 3.6 and 4.5 microns, provide immediate insights on the long-term mineralogical evolution in comparison with the existing Spitzer IRS spectra, and will bridge to similar studies that JWST will provide in the near future.

  11. Relative motion in a debris cloud

    Science.gov (United States)

    Kebe, Fatoumata

    2016-07-01

    After an explosion or collision in space, a hundred or thousands of debris are generated. To be able to study a debris cloud it's necessary to develop new analysis tools. In that sense, we have studied several representations of the relative motion with the parent body's orbit as the reference. Thus, in the case of an explosion the original spacecraft has a circular orbit which will be the reference one in the relative motion's equations while, in the case of a collision, we will take one of the spacecraft's orbit as the reference. We mainly focus on the relative motion method that used the differential elements instead of the Cartesian coordinates as it allows to take into account the main perturbation.

  12. External doses from radioactive fallout. Dosimetry and levels

    Energy Technology Data Exchange (ETDEWEB)

    Woehni, T.

    1995-12-31

    The design, manufacture and calibration of a TL-based dosemeter for measurement of low level external photon radiation are presented. The dosemeter is based on CaF{sub 2} with 2 mm brass filter for energy compensation. It is able to resolve a 8% dose increase relative to natural background radiation. With this dosemeter external dose measurements were made in 6 villages in a heavily contaminated region in Russia (Chernobyl fallout), in order to assess external doses to the population. The results were analyzed in the light of additional existing information on radioactive deposition, social habits, decontamination measures and other influencing technical and physical factors. The observed dose values were lower than theoretical estimates of external doses based on published values for external dose levels relative to the level of contamination. 84 refs., 7 figs., 5 tabs.

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

    Science.gov (United States)

    Mabit, L; Bernard, C

    2007-01-01

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

  14. Beach debris on Aruba, Southern Caribbean: Attribution to local land-based and distal marine-based sources.

    Science.gov (United States)

    de Scisciolo, Tobia; Mijts, Eric N; Becker, Tatiana; Eppinga, Maarten B

    2016-05-15

    Accumulation of marine (plastic) debris from local land-based and distal marine-based sources along coastlines is a pressing modern issue. Hitherto, assessing the relative contribution of pollution sources through beach surveys is methodologically challenging. We surveyed ten beaches along the leeward and windward coastlines of Aruba (southern Caribbean) to determine differences in macro- and meso-debris densities. Differences were quantified using three metrics: 1) the gradient in macro-debris density away from the waterfront; 2) the proportion of plastic within macro-debris; 3) the meso-:macro-debris ratio. Overall 42,585 macro-debris items and 884 meso-debris items were collected. The density of near-shore macro-debris, proportion of plastic debris herein, and meso-:macro-debris ratio were highest on the windward coastline. These results suggest that southern Caribbean windward coastlines are mainly exposed to debris originating from distal marine-based sources, and leeward coastlines to local land-based sources. Our metrics clearly reflect these differences, providing novel means to survey debris source origin.

  15. Space debris executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.; Judd, O.; Naka, R.F.

    1996-09-01

    Spacecraft, boosters, and fragments are potential hazards to space vehicles, and it is argued that collisions between them could produce a cascade that could preclude activity in LEO in 25 to 50 years. That has generated pressure for constraints on military space operations, so the AF SAB performed a study of technical aspects of the debris problem. The Study was independent of the efforts of the Air Force Space Command (AFSPC) as well as those of and NASA Johnson Space Center (JSC), which is the principal advocate for cascades and constraints. Most work on space debris has been performed by AFSPC and JSC, so the Study was in part an assessment of their efforts, in which both have been cooperative. The Study identified the main disagreements and quantified their impacts. It resolved some issues and provided bounds for the rest. It treated radar and optical observations; launch, explosion, and decay rates; and the number and distribution of fragments from explosions and collisions. That made it possible to address hazard to manned spacecraft at low altitudes and the possibility of cascading at higher altitudes, both of which now appear less likely.

  16. Space Debris Mitigation CONOPS Development

    Science.gov (United States)

    2013-06-01

    Yoshikawa, T. (2003). Space debris capture by a joint compliance controlled robot . Paper presented at the Advanced Intelligent Mechatronics , 2003. AIM...80 Robotic Arm ............................................................................................................. 80 Tethers...than 10 centimeters 79 xi Figure 34 Robotic Arm Space Debris Removal Servicer with Joint Compliance Control82 Figure 35 Prototype of brush

  17. Space debris; challenges and solutions

    NARCIS (Netherlands)

    Van Beurden, E.; Prins, C.

    2013-01-01

    Space debris has been a hot topic for the last few decades, ever since the space industry started growing exponentially. Everyone agrees that space debris is a growing problem and the saturation point has almost been reached. With a big risk of a chain reaction, called the Kessler syndrome, billions

  18. Review of medical findings in a Marshallese population twenty-six years after accidental exposure to radioactive fallout

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Space debris: modeling and detectability

    Science.gov (United States)

    Wiedemann, C.; Lorenz, J.; Radtke, J.; Kebschull, C.; Horstmann, A.; Stoll, E.

    2017-01-01

    High precision orbit determination is required for the detection and removal of space debris. Knowledge of the distribution of debris objects in orbit is necessary for orbit determination by active or passive sensors. The results can be used to investigate the orbits on which objects of a certain size at a certain frequency can be found. The knowledge of the orbital distribution of the objects as well as their properties in accordance with sensor performance models provide the basis for estimating the expected detection rates. Comprehensive modeling of the space debris environment is required for this. This paper provides an overview of the current state of knowledge about the space debris environment. In particular non-cataloged small objects are evaluated. Furthermore, improvements concerning the update of the current space debris model are addressed. The model of the space debris environment is based on the simulation of historical events, such as fragmentations due to explosions and collisions that actually occurred in Earth orbits. The orbital distribution of debris is simulated by propagating the orbits considering all perturbing forces up to a reference epoch. The modeled object population is compared with measured data and validated. The model provides a statistical distribution of space objects, according to their size and number. This distribution is based on the correct consideration of orbital mechanics. This allows for a realistic description of the space debris environment. Subsequently, a realistic prediction can be provided concerning the question, how many pieces of debris can be expected on certain orbits. To validate the model, a software tool has been developed which allows the simulation of the observation behavior of ground-based or space-based sensors. Thus, it is possible to compare the results of published measurement data with simulated detections. This tool can also be used for the simulation of sensor measurement campaigns. It is

  20. Hack's law of debris-flow basins

    Institute of Scientific and Technical Information of China (English)

    LI Yong; YUE Z.Q.; LEE C.F.; BEIGHLEY R.E.; CHEN Xiao-Qing; HU Kai-Heng; CUI Peng

    2009-01-01

    Hack's law was originally derived from basin statistics for varied spatial scales and regions.The exponent value of the law has been shown to vary between 0.47 and 0.70,causing uncertainty in its application.This paper focuses on the emergence of Hack's law from debris-flow basins in China.Over 5,000 debris-flow basins in different regions of China with drainage areas less than 100km2 are included in this study.Basins in the different regions are found to present similar distributions.Hack's law is derived fi'om maximum probability and conditional distributions,suggesting that the law should describe some critical state of basin evolution.Results suggest the exponent value is approximately 0.5.Further analysis indicates that Hack's law is related to other scaling laws underlying the evolution of a basin and that the exponent is not dependent on basin shape but rather on the evolutionary stage.A case study of a well known debris-flow basin further confirms Hack's law and its implications in basin evolution.

  1. Debris Flow Occurrence and Sediment Persistence, Upper Colorado River Valley, CO

    Science.gov (United States)

    Grimsley, K. J.; Rathburn, S. L.; Friedman, J. M.; Mangano, J. F.

    2016-07-01

    Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

  2. Debris Flow Occurrence and Sediment Persistence, Upper Colorado River Valley, CO.

    Science.gov (United States)

    Grimsley, K J; Rathburn, S L; Friedman, J M; Mangano, J F

    2016-07-01

    Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

  3. Debris flow occurrence and sediment persistence, Upper Colorado River Valley, CO

    Science.gov (United States)

    Grimsley, Kyle J; Rathburn, Sara L.; Friedman, Jonathan M.; Mangano, Joseph F.

    2016-01-01

    Debris flow magnitudes and frequencies are compared across the Upper Colorado River valley to assess influences on debris flow occurrence and to evaluate valley geometry effects on sediment persistence. Dendrochronology, field mapping, and aerial photographic analysis are used to evaluate whether a 19th century earthen, water-conveyance ditch has altered the regime of debris flow occurrence in the Colorado River headwaters. Identifying any shifts in disturbance processes or changes in magnitudes and frequencies of occurrence is fundamental to establishing the historical range of variability (HRV) at the site. We found no substantial difference in frequency of debris flows cataloged at eleven sites of deposition between the east (8) and west (11) sides of the Colorado River valley over the last century, but four of the five largest debris flows originated on the west side of the valley in association with the earthen ditch, while the fifth is on a steep hillslope of hydrothermally altered rock on the east side. These results suggest that the ditch has altered the regime of debris flow activity in the Colorado River headwaters as compared to HRV by increasing the frequency of debris flows large enough to reach the Colorado River valley. Valley confinement is a dominant control on response to debris flows, influencing volumes of aggradation and persistence of debris flow deposits. Large, frequent debris flows, exceeding HRV, create persistent effects due to valley geometry and geomorphic setting conducive to sediment storage that are easily delineated by valley confinement ratios which are useful to land managers.

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

    Science.gov (United States)

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

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

  5. Influence of radioactive fallout on water supply and sewerage in Finland; Radioaktiivisen laskeuman vaikutukset vesihuoltoon

    Energy Technology Data Exchange (ETDEWEB)

    Rantavaara, A.; Saxen, R.; Puhakainen, M. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Hatva, T.; Ahosilta, P.; Tenhunen, J. [National Board of Waters and the Environment, Helsinki (Finland)

    1995-09-01

    The report reviews the practices and organization of water supply and sewerage in Finland and is related to their response to radioactive fallout situations. The contribution of drinking water to the internal radiation dose caused by radioactive fallout has earlier been small in Finland. However, in a wide-scale fallout situation, the decreasing of collective dose received from water may be justified, if the dose can be reduced at a reasonable cost, for instance by a temporary change of the raw water source. Efficient exchange of information between radiation protection and water supply experts is important for successful dose reduction measures. In Finland waterworks deliver tap water to 4.2 million people. Half of the water is ground water, and generally very well protected against fallout radioactivity. The other half is treated surface water. (6 figs., 5 tabs.).

  6. Volcanic Debris Flows of the Latest Paleozoic Arbasay Formation: Geomorphological Characters and Paleoenvironment Reconstruction of Northern Tian Shan, NW China

    Science.gov (United States)

    Yang, W.; Liu, D.; Guo, Z.

    2015-12-01

    Texturally well-preserved volcanic debris flows (also called lahars) are exposed in the Latest Paleozoic Arbasay Formation, Northern Tian Shan. LA-ICP-MS zircon dating of the intercalated fallout tuff sample provided an age of 314.4±3.4 Ma (MSWD=1.6), suggesting they were deposited at Latest Carboniferous. The lahars consist primarily of two lithofacies: massive, poorly lithified diamictites and stratified, moderately lithified gravelly sandstones. The diamictites can be generally divided into two subfacies, i.e., the matrix-supported and the clast-supported diamictites. Most diamictites are structureless and nongraded. They are thick in beds and contain large clasts up to 3 m in dimension. The gravelly sandstones display much finer particle size and have wedge or lenticular geometries. Large clasts are absent within them and the sorting characters are much better than the diamictites. Despite the different size grading, the matrix and the clasts of the two lithofacies appear to be homogeneous. The matrix is generally sandy mudstone. The clasts comprise rhyolites, dacites, andesites, andesitic basalts and basalts, same to the co-existing volcanic rocks, suggesting they originate from the cognate volcanics. The disorganized diamictites are supposed to deposit from a turbulent flood or pyroclastic surge. The gravelly sandstone lithofacies are interpreted as sand-rich flood flows or hyperconcentrated flood flows during the waning stage of a mass-flow event. The overall characteristics of the deposits suggest a mass-flow dominated alluvial fan environment. It's noteable that several syn- sedimentary normal faults occurred within these lahar deposits, indicating that the Southern Junggar Basin was in an extensional regime during the lahars' deposition. Structure is dominated by normal faulting, allowing the existence of relatively small, highly compartmentalized depocenters. This is also supported by geochemistry and detrital zircon studies.

  7. Problems of Small Debris

    Directory of Open Access Journals (Sweden)

    V. V. Zelentsov

    2015-01-01

    Full Text Available During the exploration of outer space (as of 1/1 2011 6853 was launched spacecraft (SC are successful 6264, representing 95% of the total number of starts. The most intensively exploited space Russia (USSR (3701 starts, 94% successful, USA (2774 starts, 90% successful, China (234 starts, 96% successful and India (89 starts, 90% successful. A small part of running the spacecraft returned to Earth (manned spacecraft and transport, and the rest remained in orbit. Some of them are descended from orbit and burned up in the atmosphere, the rest remained in the OCP and turned into space debris (SD.The composition of the Cabinet is diverse: finish the job spacecraft; boosters and the last stage of launch vehicles left in orbit after SC injection; technological waste arising during the opening drop-down structures and fragments of the destroyed spacecraft. The resulting explosion orbital SD forms ellipsoidal region which orbits blasted object. Then, as a result of precession, is the distribution of objects in orbit explosion exploding spacecraft.The whole Cabinet is divided into two factions: the observed (larger than 100 mm and not observed (less than 100 mm. Observed debris katalogalizirovan and 0.2% of the total number of SD, there was no SD is the bulk - 99.8%.SC meeting working with a fragment observed SD predictable and due to changes in altitude spacecraft avoids a possible meeting. Contact spacecraft with large fragment lead to disaster (which took place at a meeting of the Russian communications satellite "Cosmos-2251" and the American machine "Iridium". Meeting with small SD is not predictable, especially if it was formed by an explosion or collision fragments together. Orbit that KM is not predictable, and the speed can be up to 10 km / s. Meeting with small particle SD no less dangerous for the spacecraft. The impact speed of spacecraft with space debris particles can reach up to 10 ... 15 km / s at such speeds the breakdown probability thin

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

    OpenAIRE

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

    2010-01-01

    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 an...

  9. Aliphatic and aromatic hydrocarbons in particulate fallout of Alexandria, Egypt: Sources and implications

    Energy Technology Data Exchange (ETDEWEB)

    Aboul-Kassim, T.A.T.; Simoneit, B.R.T. [Oregon State Univ., Corvallis, OR (United States)

    1995-10-01

    Particulate fallout samples (PFS) were collected in Alexandria, and their aliphatic and aromatic hydrocarbon compositions were determined both quantitatively and qualitatively to characterize the homologous and biomarker compounds in terms of their original sources. The results show that all samples contain aliphatic hydrocarbons, including n-alkanes, UCM, isoprenoids, tri- and tetracyclic terpanes, hopanes, and steranes/diasteranes. The main source of these compounds is from petrochemical contamination with trace input of terrestrial higher plant wax. In addition, polycyclic aromatic hydrocarbons, which are considered to be combustion products from fossil fuels such as petroleum, are also widely distributed in all samples. Multivariate statistical analysis, including extended Q-mode factor analysis and linear programming technique, was performed in order to reduce the hydrocarbon data set into a meaningful number of end members (sources). This analysis indicates that there are two significant end members explaining 90% of the total variation among the samples and confirming petrochemical (79.6%), and thermogenic/pyrolytic (10.4%) sources in the PFS model. 65 refs., 7 figs., 4 tabs.

  10. Active Space Debris Removal System

    Directory of Open Access Journals (Sweden)

    Gabriele GUERRA

    2017-06-01

    Full Text Available Since the start of the space era, more than 5000 launches have been carried out, each carrying satellites for many disparate uses, such as Earth observation or communication. Thus, the space environment has become congested and the problem of space debris is now generating some concerns in the space community due to our long-lived belief that “space is big”. In the last few years, solutions to this problem have been proposed, one of those is Active Space Debris Removal: this method will reduce the increasing debris growth and permit future sustainable space activities. The main idea of the method proposed below is a drag augmentation system: use a system capable of putting an expanded foam on a debris which will increase the area-to-mass ratio to increase the natural atmospheric drag and solar pressure. The drag augmentation system proposed here requires a docking system; the debris will be pushed to its release height and then, after un-docking, an uncontrolled re-entry takes place ending with a burn up of the object and the foam in the atmosphere within a given time frame. The method requires an efficient way to change the orbit between two debris. The present paper analyses such a system in combination with an Electric Propulsion system, and emphasizes the choice of using two satellites to remove five effective rockets bodies debris within a year.

  11. The earth orbiting space debris

    Directory of Open Access Journals (Sweden)

    Rossi A.

    2005-01-01

    Full Text Available The space debris population is similar to the asteroid belt, since it is subject to a process of high-velocity mutual collisions that affects the long-term evolution of its size distribution. Presently, more than 10 000 artificial debris particles with diameters larger than 10 cm (and more than 300 000 with diameters larger than 1 cm are orbiting the Earth, and are monitored and studied by a large network of sensors around the Earth. Many objects of different kind compose the space debris population, produced by different source mechanisms ranging from high energy fragmentation of large spacecraft to slow diffusion of liquid metal. The impact against a space debris is a serious risk that every spacecraft must face now and it can be evaluated with ad-hoc algorithms. The long term evolution of the whole debris population is studied with computer models allowing the simulation of all the known source and sink mechanisms. One of these codes is described in this paper and the evolution of the debris environment over the next 100 years, under different traffic scenarios, is shown, pointing out the possible measures to mitigate the growth of the orbital debris population. .

  12. 14 CFR 417.211 - Debris analysis.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Debris analysis. 417.211 Section 417.211... TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.211 Debris analysis. (a) General. A flight safety analysis must include a debris analysis. For an orbital or suborbital launch, a debris...

  13. Debris Engine: A Potential Thruster for Space Debris Removal

    CERN Document Server

    Lan, Lei; Baoyin, Hexi

    2015-01-01

    We present a design concept for a space engine that can continuously remove the orbit debris by using the debris as a propellant. Space robotic cleaner is adopted to capture the targeting debris and to transfer them into the engine. Debris with larger size is first disintegrated into small pieces by using a mechanical method. The planetary ball mill is then adopted to grind the pieces into micrometer or smaller powder. The energy needed in this process is get from the nuclear and solar power. By the effect of gamma-ray photoelectric or the behavior of tangently rub of tungsten needles, the debris powered is charged. This behavior can be used to speed up the movement of powder in a tandem electrostatic particle accelerator. By ejecting the high-temperture and high-pressure charged powered from the nozzle of the engine,the continuously thrust is obtained. This thrust can be used to perform orbital maneuver and debris rendezvous for the spacecraft and robotic cleaner. The ejected charged particle will be blown a...

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

    Energy Technology Data Exchange (ETDEWEB)

    Grinstein, Fernando F [Los Alamos National Laboratory; Wachtor, Adam J [Los Alamos National Laboratory; Nelson, Matt [Los Alamos National Laboratory; Brown, Michael [Los Alamos National Laboratory; Bos, Randy [Los Alamos National Laboratory; Patnik, Gopal [US NAVAL RESEARCH LAB.

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Global risk of radioactive fallout after nuclear reactor accidents

    Science.gov (United States)

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

    2012-04-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  19. Fate of metal-associated POM in a soil under arable land use contaminated by metallurgical fallout in northern France.

    Science.gov (United States)

    Labanowski, Jérôme; Sebastia, Julien; Foy, Eddy; Jongmans, Toine; Lamy, Isabelle; van Oort, Folkert

    2007-09-01

    Organic matter is a major metal-retaining constituent in soils. Among the diversity of organic components in soils, particulate organic matter (POM) accumulates large amounts of metals, but the fate of such metal-associated POM is unknown. We studied different POM size fractions and their corresponding mineral size-fractions isolated from the surface horizon of a soil affected by metallurgical fallout. Analyses of total and EDTA extractible metal contents performed on all size fractions demonstrated that with decreasing POM size, larger metal concentrations were observed but they were less extractable. Micromorphological study revealed the occurrence of opaque parts in decaying POM fragments and their individualization as fine, irregularly shaped opaque fragments in the soil matrix. This work suggested a mutual sequestration of metal pollutants and organic carbon as micro-meter sized, metal-enriched organic particles derived from POM, representing an original pathway for natural attenuation of risk related to metal contaminated soils.

  20. Effects of basal debris on glacier flow.

    Science.gov (United States)

    Iverson, Neal R; Cohen, Denis; Hooyer, Thomas S; Fischer, Urs H; Jackson, Miriam; Moore, Peter L; Lappegard, Gaute; Kohler, Jack

    2003-07-04

    Glacier movement is resisted partially by debris, either within glaciers or under glaciers in water-saturated layers. In experiments beneath a thick, sliding glacier, ice containing 2 to 11% debris exerted shear traction of 60 to 200 kilopascals on a smooth rock bed, comparable to the total shear traction beneath glaciers and contrary to the usual assumption that debris-bed friction is negligible. Imposed pore-water pressure that was 60 to 100% of the normal stress in a subglacial debris layer reduced shear traction on the debris sufficiently to halt its deformation and cause slip of ice over the debris. Slip resistance was thus less than debris shearing resistance.

  1. Observations of Titan IIIC Transtage Fragmentation Debris

    Science.gov (United States)

    Cowardin, Heather; Seitzer, P.; Abercromby, K.; Barker, E.; Buckalew, B.; Cardona, T.; Krisko, P.; Lederer, S.

    2013-01-01

    The fragmentation of a Titan IIIC Transtage (1968-081) on 21 February 1992 is one of only two known break-ups in or near geosynchronous orbit. The original rocket body and 24 pieces of debris are currently being tracked by the U. S. Space Surveillance Network (SSN). The rocket body (SSN# 3432) and several of the original fragments (SSN# 25000, 25001, 30000, and 33511) were observed in survey mode during 2004-2010 using the 0.6-m Michigan Orbital DEbris Survey Telescope (MODEST) in Chile using a broad R filter. This paper presents a size distribution for all calibrated magnitude data acquired on MODEST. Size distribution plots are also shown using historical models for small fragmentation debris (down to 10 cm) thought to be associated with the Titan Transtage break-up. In November 2010, visible broadband photometry (Johnson/Kron-Cousins BVRI) was acquired with the 0.9-m Small and Moderate Aperture Research Telescope System (SMARTS) at the Cerro Tololo Inter-American Observatory (CTIO) in Chile on several Titan fragments (SSN 25001, 33509, and 33510) and the parent rocket body (SSN 3432). Color index data are used to determine the fragment brightness distribution and how the data compares to spacecraft materials measured in the laboratory using similar photometric measurement techniques. In order to better characterize the break-up fragments, spectral measurements were acquired on three Titan fragments (one fragment observed over two different time periods) using the 6.5-m Magellan telescopes at Las Campanas Observatory in Chile. The telescopic spectra of SSN 25000 (May 2012 and January 2013), SSN 38690, and SSN 38699 are compared with laboratory acquired spectra of materials (e.g., aluminum and various paints) to determine the surface material.

  2. NASA Orbital Debris Baseline Populations

    Science.gov (United States)

    Krisko, Paula H.; Vavrin, A. B.

    2013-01-01

    The NASA Orbital Debris Program Office has created high fidelity populations of the debris environment. The populations include objects of 1 cm and larger in Low Earth Orbit through Geosynchronous Transfer Orbit. They were designed for the purpose of assisting debris researchers and sensor developers in planning and testing. This environment is derived directly from the newest ORDEM model populations which include a background derived from LEGEND, as well as specific events such as the Chinese ASAT test, the Iridium 33/Cosmos 2251 accidental collision, the RORSAT sodium-potassium droplet releases, and other miscellaneous events. It is the most realistic ODPO debris population to date. In this paper we present the populations in chart form. We describe derivations of the background population and the specific populations added on. We validate our 1 cm and larger Low Earth Orbit population against SSN, Haystack, and HAX radar measurements.

  3. Disaster Debris Recovery Database - Recovery

    Data.gov (United States)

    U.S. Environmental Protection Agency — The US EPA Region 5 Disaster Debris Recovery Database includes public datasets of over 6,000 composting facilities, demolition contractors, transfer stations,...

  4. Disaster Debris Recovery Database - Landfills

    Data.gov (United States)

    U.S. Environmental Protection Agency — The US EPA Region 5 Disaster Debris Recovery Database includes public datasets of over 6,000 composting facilities, demolition contractors, transfer stations,...

  5. EUV and debris characteristics of a laser-plasma tin dioxide nano-particle colloidal jet target

    Science.gov (United States)

    Kaku, Masanori; Suetake, Sumihiro; Senba, Yusuke; Katto, Masahito; Kubodera, Shoichi

    2008-03-01

    Debris characteristics and its reduction have been investigated for a laser-produced plasma (LPP) extreme ultraviolet (EUV) source using a colloidal jet target containing tin dioxide nano-particles. Dominant deposited debris on a witness plate was found to have a form of oxidized tin (SnO x) originated from nano-particles. Quantitative debris amounts were determined by total laser energy irradiated onto a target, not by laser irradiation modes, such as single or double pulse irradiation. In-situ low-temperature (100°C) heating of a plate was effective to reduce the deposited debris amount, since colloidal debris was easily vaporized by the heat. Another approach to remove the deposited debris was roomtemperature photon processing using incoherent vacuum ultraviolet (VUV) emission at 126 nm. X-ray photoelectron spectroscopy (XPS) analysis has shown that the deposited SnOx debris layer was deoxidized by the 126 nm VUV photon energy.

  6. Collisional Grooming of Debris Disks

    CERN Document Server

    Kuchner, Marc J

    2009-01-01

    Debris disk images show clumps, rings, warps, and other structures, many of which have been interpreted as perturbations from hidden planets. But so far, no models of these structures have properly accounted for collisions between dust grains. We have developed new steady-state 3D models of debris disks that self-consistently incorporate grain-grain collisions. We summarize our algorithm and use it to illustrate how collisions interact with resonant trapping in the presence of a planet.

  7. Hydraulic System Wear Debris Analysis.

    Science.gov (United States)

    1982-08-03

    drawn. Each one-=L sample was drawn with a clean plastic pipette of one-mL capacity. The samples were placed in clean Ferrogram preparation bottles ...and from cavities in a block which held linear seals into sampling bottles . Several photographs of this debris , which was deposited on Ferro- grams...silicon in the glass overshadowed the elements of the wear debris . To overcome this difficulty, the Ferrogram should be pre- pared on a carbon-filled

  8. New advances for modelling the debris avalanches

    Science.gov (United States)

    Cuomo, Sabatino; Cascini, Leonardo; Pastor, Manuel; Castorino, Giuseppe Claudio

    2013-04-01

    Flow-like landslides are a major global hazard and they occur worldwide causing a large number of casualties, significant structural damages to property and infrastructures as well as economic losses. When involving open slopes, these landslides often occur in triangular source areas where initial slides turn into avalanches through further failures and/or eventual soil entrainment. This paper deals with the numerical modelling of the propagation stage of debris avalanches which provides information such as the propagation pattern of the mobilized material, its velocity, thickness and run-out distance. In the paper, a "depth integrated" model is used which allows: i) adequately taking into account the irregular topography of real slopes which greatly affect the propagation stage and ii) using a less time consuming model than fully 3D approaches. The used model is named "GeoFlow_SPH" and it was formerly applied to theoretical, experimental and real case histories (Pastor et al., 2009; Cascini et al., 2012). In this work the behavior of debris avalanches is analyzed with special emphasis on the apical angle, one of the main features of this type of landslide, in relation to soil rheology, hillslope geometry and features of triggering area. Furthermore, the role of erosion has been investigated with reference to the uppermost parts of open slopes with a different steepness. These analyses are firstly carried out for simplified benchmark slopes, using both water-like materials (with no shear strength) and debris type materials. Then, three important case studies of Campania region (Cervinara, Nocera Inferiore e Sarno) are analyzed where debris avalanches involved pyroclastic soils originated from the eruptive products of Vesusius volcano. The results achieved for both benchmark slopes and real case histories outline the key role played by the erosion on the whole propagation stage of debris avalanches. The results are particularly satisfactory since they indicate the

  9. A Comparison in the Accuracy of Mapping Nuclear Fallout Patterns Using HPAC, HYSPLIT, DELFIC FPT and an AFIT FORTRAN95 Fallout Deposition ode

    Science.gov (United States)

    2011-03-01

    constant support, suggestions and love and our unborn son who did not make me to nauseous to continue my journey. I am deeply grateful to my dogs Herbie...radioactive hazard that could potentially lead to injury and possibly death to living systems. The base knowledge of fallout deposition and residual

  10. Removing Orbital Debris with Lasers

    CERN Document Server

    Phipps, Claude R; Bradford, Brian; George, E Victor; Libby, Stephen B; Liedahl, Duane A; Marcovici, Bogdan; Olivier, Scot S; Pleasance, Lyn D; Reilly, James P; Rubenchik, Alexander; Strafford, David N; Valley, Michael T

    2011-01-01

    Orbital debris in low Earth orbit (LEO) are now sufficiently dense that the use of LEO space is threatened by runaway collisional cascading. A problem predicted more than thirty years ago, the threat from debris larger than about 1 cm demands serious attention. A promising proposed solution uses a high power pulsed laser system on the Earth to make plasma jets on the objects, slowing them slightly, and causing them to re-enter and burn up in the atmosphere. In this paper, we reassess this approach in light of recent advances in low-cost, light-weight modular design for large mirrors, calculations of laser-induced orbit changes and in design of repetitive, multi-kilojoule lasers, that build on inertial fusion research. These advances now suggest that laser orbital debris removal (LODR) is the most cost-effective way to mitigate the debris problem. No other solutions have been proposed that address the whole problem of large and small debris. A LODR system will have multiple uses beyond debris removal. Internat...

  11. Fallout Radionuclides as Tracers in Southern Alps Sediment Studies

    Science.gov (United States)

    Carey, A. E.; Karanovic, Z.; Dibb, J. E.

    2005-12-01

    The primary geologic processes shaping the landscape are physical and chemical weathering and the transport of solids by erosion. As part of our studies on the coupling between physical erosion and chemical weathering, we have determined depositional and erosional processes in New Zealand's tectonically active, rapidly uplifting Southern Alps, specifically focusing on the Hokitika River watershed. The South Island watersheds we are studying are subject to extreme orographic precipitation (as high as 7-12 m annually) and high landslide frequency, but have modest topography due to the rapid erosion. In concert with our studies of chemical weathering and physical erosion, we have used the atmospherically-delivered radionuclides of 7Be, 137Cs and 210Pbexcess to determine the relative magnitude of particle residence time in the high elevation Cropp and Whitcombe subwatersheds and the rates of sedimentation. One- and two-box modeling with 7Be and 210Pbexcess was used to determine soil and sediment residence times. Residence time of fine suspended particles is short and particles can travel the length of the river during a single storm, probably due to the short duration, high-intensity rainfalls which produce rapidly moving, steep flood waves. The readily detected peak of 137Cs activity in Cropp terrace and Hokitika gorge soils yielded sedimentation rates of 0.06-0.12 cm yr-1. At the Cropp terrace, inventory models of 210Pbexcess yield soil accumulation rates significantly less than those determined using the 137Cs activity peak. We attribute the differences to overestimation of 210Pbexcess in surface soils and to contrasting fallout fluxes, geochemical behavior and radionuclide contents of sedimenting materials. Total inventories of 210Pbexcess in soils greatly exceed the expected direct atmospheric deposition, suggesting that lateral transport of this nuclide occurs within the watershed. At the Hokitika gorge, all nuclides studied yielded similar sedimentation rates

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

    Science.gov (United States)

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

    2012-05-01

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

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

    Directory of Open Access Journals (Sweden)

    J. Lelieveld

    2012-05-01

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

  14. Space Debris Environment Remediation Concepts

    Science.gov (United States)

    Johnson, Nicholas L.; Klinkrad, Heiner

    2009-01-01

    Long-term projections of the space debris environment indicate that even drastic measures, such as an immediate, complete halt of launch and release activities, will not result in a stable environment of man-made space objects. Collision events between already existing space hardware will within a few decades start to dominate the debris population, and result in a net increase of the space debris population, also in size regimes which may cause further catastrophic collisions. Such a collisional cascading will ultimately lead to a run-away situation ("Kessler syndrome"), with no further possibility of human intervention. The International Academy of Astronautics (IAA) has been investigating the status and the stability of the space debris environment in several studies by first looking into space traffic management possibilities and then investigating means of mitigating the creation of space debris. In an ongoing activity, an IAA study group looks at ways of active space debris environment remediation. In contrast to the former mitigation study, the current activity concentrates on the active removal of small and large objects, such as defunct spacecraft, orbital stages, and mission-related objects, which serve as a latent mass reservoir that fuels initial catastrophic collisions and later collisional cascading. The paper will outline different mass removal concepts, e.g. based on directed energy, tethers (momentum exchange or electrodynamic), aerodynamic drag augmentation, solar sails, auxiliary propulsion units, retarding surfaces, or on-orbit capture. Apart from physical principles of the proposed concepts, their applicability to different orbital regimes, and their effectiveness concerning mass removal efficiency will be analyzed. The IAA activity on space debris environment remediation is a truly international project which involves more than 23 contributing authors from 9 different nations.

  15. Adaptive optics for laser space debris removal

    Science.gov (United States)

    Bennet, Francis; Conan, Rodolphe; D'Orgeville, Celine; Dawson, Murray; Paulin, Nicolas; Price, Ian; Rigaut, Francois; Ritchie, Ian; Smith, Craig; Uhlendorf, Kristina

    2012-07-01

    Space debris in low Earth orbit below 1500km is becoming an increasing threat to satellites and spacecrafts. Radar and laser tracking are currently used to monitor the orbits of thousands of space debris and active satellites are able to use this information to manoeuvre out of the way of a predicted collision. However, many satellites are not able to manoeuvre and debris-on debris collisions are becoming a signicant contributor to the growing space debris population. The removal of the space debris from orbit is the preferred and more denitive solution. Space debris removal may be achieved through laser ablation, whereby a high power laser corrected with an adaptive optics system could, in theory, allow ablation of the debris surface and so impart a remote thrust on the targeted object. The goal of this is to avoid collisions between space debris to prevent an exponential increase in the number of space debris objects. We are developing an experiment to demonstrate the feasibility of laser ablation for space debris removal. This laser ablation demonstrator utilises a pulsed sodium laser to probe the atmosphere ahead of the space debris and the sun re ection of the space debris is used to provide atmospheric tip{tilt information. A deformable mirror is then shaped to correct an infrared laser beam on the uplink path to the debris. We present here the design and the expected performance of the system.

  16. Has fallout from the Chernobyl accident caused childhood leukaemia in Europe? An update on epidemiologic evidence

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, W. [Bremen Inst. for Prevention Research and Social Medicine (BIPS), Bremen (Germany)

    2001-07-01

    Background: According to radiation risk estimates uniformly adopted by various official organizations, exposure to Chernobyl fallout is unlikely to have caused any measurable health risk in central Europe. Methods and Results: A reevaluation of ECLIS (European Childhood Leukaemia and Lymphoma Incidence Study), a large IARC-coordinated project revealed a slightly higher leukaemia incidence in the most contaminated European regions, and an increasing trend with estimated cumulative excess radiation dose. The excess corresponds to 20 cases of childhood leukaemia in the study area until 1991. Recent evidence from Greece and Germany indicate significantly higher risks in the cohort of children in utero at the time of the initial fallout. In Greece, a positive trend was observed over three regions of increasing average fallout contamination (p=0.005). Conclusion: Chernobyl fallout could well have caused a small, but significant excess of childhood leukaemia cases in Europe. The etiologic mechanism might include an induction of chromosome aberrations in early pregnancy. Increased risks in the birth cohort exposed in utero correspond to 11 excess cases in Greece and another 11.4 excess cases in Germany alone. Exposure misclassification and underascertainment of incident cases render post-Chernobyl risk estimates probably too low. If indeed Chernobyl fallout has caused childhood leukaemia cases in Europe, we would also expect an increased incidence for other childhood cancers and excess malignancies in adults as well as non-malignant diseases of all ages. Neither of these endpoints have as yet been systematically studied. (orig.)

  17. Debris-flow observations in the Zermatt Valley

    Science.gov (United States)

    Graf, Christoph

    2015-04-01

    In the Alps, a multitude of unstable slopes is located at altitudes of ~2700 m asl, where sediment transfers typically happen outside the range of humans or their infrastructure. The situation is slightly different in the Zermatt Valley, a high-elevation, north-south oriented glacial valley in the Swiss Alps, where the detachment of melting permafrost results in rock falls on steep slopes and debris flows in high-gradient gullies through which till is transferred directly to the inhabited valley floor at elevations between 1100 (N) and 1600 m asl (S). As a result of the excellent database on past disasters in the valley, recent developments and measurements in the local rock glacier bodies and current torrential events, I show data from some debris-flow torrents to document impacts of past, ongoing and possible future changes of debris flows originating from periglacial environments. Debris flows are typically initiated by the abrupt input of considerable quantities of water. The water-saturated masses of fragmented rock and soil slump down mountainsides into gullies which in turn mobilize stored sediment in the channels. In addition to triggering by extreme rainstorms, debris flows have also been reported to be released by rapid snowmelt, rain-on-snow storms, or the sudden emptying of glacier water bodies or through the rupture of landslide dams. More frequently, debris flows occur as a result of high-intensity, convective rainstorms of short duration or low-intensity advective precipitation events over several days. Displacement rates and instability of rock glaciers have increased further recently to show movement rates without historical precedents. At Grabengufer (Dorfbach) e.g., increasing air and ice temperatures have favoured the development of annual displacement rates from just a few decimetres in the past decades to 80 m in 2010. Similar behaviour was observed in catchments nearby. As a consequence of the enhanced movement of these permafrost bodies and

  18. Hydroplaning and submarine debris flows

    Science.gov (United States)

    de Blasio, Fabio V.; Engvik, Lars; Harbitz, Carl B.; ElverhøI, Anders

    2004-01-01

    Examination of submarine clastic deposits along the continental margins reveals the remnants of holocenic or older debris flows with run-out distances up to hundreds of kilometers. Laboratory experiments on subaqueous debris flows, where typically one tenth of a cubic meter of material is dropped down a flume, also show high velocities and long run-out distances compared to subaerial debris flows. Moreover, they show the tendency of the head of the flow to run out ahead of the rest of the body. The experiments reveal the possible clue to the mechanism of long run-out. This mechanism, called hydroplaning, begins as the dynamic pressure at the front of the debris flow becomes of the order of the pressure exerted by the weight of the sediment. In such conditions a layer of water can intrude under the sediment with a lubrication effect and a decrease in the resistance forces between the sediment and the seabed. A physical-mathematical model of hydroplaning is presented and investigated numerically. The model is applied to both laboratory- and field-scale debris flows. Agreement with laboratory experiments makes us confident in the extrapolation of our model to natural flows and shows that long run-out distances can be naturally attained.

  19. Modelling (137)Cs concentrations in moose (1986-2012) from areas highly contaminated by the Chernobyl fallout.

    Science.gov (United States)

    Weimer, Robert N; Sundell-Bergman, Synnöve; Sonesten, Lars; Wikenros, Camilla; Rosén, Klas

    2016-08-01

    Data from long term annual monitoring of (137)Cs concentrations in harvested moose (Alces alces) were empirically modelled by applying multivariate data analysis that is able to from relatively raw datasets show how the many various impact variables are related (Principal component analysis, PCA). In the later stage regression modelling (Partial least squares, PLS) was applied to analyse which environmental and physiological factors were significant (i.e. of predictive value) based on the measured (X) activity concentrations in moose meat. The data sets originate from two different forest dominated areas in Sweden. One area is located inland (Heby municipality) and the other borders to the Baltic Sea (Gävle municipality). In inland with 20% farmland, GIS-software was used to calculate the proportion of different habitat types and (137)Cs deposition around individual killing spots. This model reveals that the proportions of farmland and forest around the killing spot were significant parameters, second to deposition and years since fallout. Significance was also obtained for the proportions of mire and water bodies, the amount of rain in summer and the age of the moose. In the other model based on data from the coastal area with only about 4% farmland, the coordinates of the moose killing spots were not recorded in the data sets. In the resulting model the temperature in July was the most important parameter, second to years since fallout. Significance was also found for the following parameters: temperature and rainfall in several summer months, the approximate north- and eastward location of the killing spot and to which age category (adult/calf) the harvested moose belonged.

  20. Debris Disks in Nearby Young Moving Groups in the ALMA Era

    CERN Document Server

    Kóspál, Á

    2015-01-01

    Many members of nearby young moving groups exhibit infrared excess attributed to circumstellar debris dust, formed via erosion of planetesimals. With their proximity and well-dated ages, these groups are excellent laboratories for studying the early evolution of debris dust and of planetesimal belts. ALMA can spatially resolve the disk emission, revealing the location and extent of these belts, putting constraints on planetesimal evolution models, and allowing us to study planet-disk interactions. While the main trends of dust evolution in debris disks are well-known, there is almost no information on the evolution of gas. During the transition from protoplanetary to debris state, even the origin of gas is dubious. Here we review the exciting new results ALMA provided by observing young debris disks, and discuss possible future research directions.

  1. Oceanic barnacles act as foundation species on plastic debris: implications for marine dispersal.

    Science.gov (United States)

    Gil, Michael A; Pfaller, Joseph B

    2016-01-27

    Plastic has emerged as an abundant, stable substratum for oceanic dispersal of organisms via rafting. However, the ecological mechanisms underlying community diversity on plastic debris remain poorly understood. On a cruise from California to Hawai'i, we surveyed plastic debris, some likely originating from the 2011 Tōhoku tsunami, to examine the relationship between rafting community diversity and both habitat area and stalked barnacle (Lepas spp.) abundance. For sessile taxa richness, we observed an interaction in which the positive effect of debris area weakened the negative effect of barnacle cover. In contrast, for mobile taxa richness, including cohabiting species from opposite sides of the Pacific Ocean, barnacle abundance had a positive effect that was strongest at smaller debris sizes. These findings suggest that barnacles, through interactions with habitat area, have trait-dependent effects on other species, serving as both foundation species and competitors, mediating the diversity and dispersal potential of marine organisms on plastic debris.

  2. A dynamic approach to monitoring particle fallout in a cleanroom environment

    Science.gov (United States)

    Perry, Radford L., III

    2010-08-01

    Previous studies have correlated the particle fallout rates within cleanrooms to MIL-STD-1246 cleanliness levels. Unfortunately "cleanliness levels" are not linear and do not lead to easily understood increases with respect to either cleanroom class or time. Additionally, cleanroom "class" is rarely static but varies throughout the processing flow in accordance with the activity levels. A numerical evaluation of the particle fallout normalized to area coverage demonstrates a correlation that is directly proportional to both cleanroom class and exposure time, yielding a simple Class-Hour formulation. Application of this formulation allows for dynamic monitoring of the projected fallout rates using a standard air particle counter. The theoretical results compare favorably with historical data and recent studies.

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

    Energy Technology Data Exchange (ETDEWEB)

    Michel, H. E-mail: herve.michel@unice.fr; Barci-Funel, G.; Dalmasso, J.; Ardisson, G.; Appleby, P.G.; Haworth, E.; El-Daoushy, F

    2002-07-01

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

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

    Science.gov (United States)

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

    2002-01-01

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

  5. Relevance of Fukushima Nuclear Accident to India: Nuclear Radiation Risk and Interventions to Mitigate Adverse Fallout

    Directory of Open Access Journals (Sweden)

    Yadav Kapil, Varshney Neha, Aslesh OP, Karmakar MG, Pandav Chandrakant S

    2012-09-01

    Full Text Available The environmental radiation release from Fukushima nuclear power following tsunami in Japan has once again highlighted the omnipotent risk of radiation injury in the today’s world. India is at a real risk from radiation fallout both due to nuclear power plant accidents and nuclear warfare threat. The risk from nuclear radiation accident in India is further increased by the region being endemic for iodine deficiency as adverse effects following nuclear radiation fallout like thyroid cancer is significantly higher in iodine deficient populations .There is need to institute disaster preparedness measures to mitigate the damage in case of a nuclear accident. Interventions to control adverse fallout of nuclear radiation include evacuation, sheltering and food controls as well as iodine prophylaxis

  6. Fractal Structure of Debris Flow

    Institute of Scientific and Technical Information of China (English)

    LI Yong; LIU Jingjing; HU Kaiheng; CHEN Xiaoqing

    2007-01-01

    One of the most remarkable characteristics of debris flow is the competence for supporting boulders on the surface of flow, which strongly suggests that there should be some structure in the fluid body. This paper analyzed the grain compositions from various samples of debris flows and then revealed the fractal structure. Specifically, the fractality holds in three domains that can be respectively identified as the slurry, matrix, and the coarse content. Furthermore, the matrix fractal, which distinguishes debris flow from other kinds of flows, involves a hierarchical structure in the sense that it might contain ever increasing grains while the total range of grain size increases. It provides a possible mechanism for the boulder suspension.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  9. Debris Discs: Modeling/theory review

    Science.gov (United States)

    Thébault, P.

    2012-03-01

    An impressive amount of photometric, spectroscopic and imaging observations of circumstellar debris discs has been accumulated over the past 3 decades, revealing that they come in all shapes and flavours, from young post-planet-formation systems like Beta-Pic to much older ones like Vega. What we see in these systems are small grains, which are probably only the tip of the iceberg of a vast population of larger (undetectable) collisionally-eroding bodies, leftover from the planet-formation process. Understanding the spatial structure, physical properties, origin and evolution of this dust is of crucial importance, as it is our only window into what is going on in these systems. Dust can be used as a tracer of the distribution of their collisional progenitors and of possible hidden massive pertubers, but can also allow to derive valuable information about the disc's total mass, size distribution or chemical composition. I will review the state of the art in numerical models of debris disc, and present some important issues that are explored by current modelling efforts: planet-disc interactions, link between cold (i.e. Herschel-observed) and hot discs, effect of binarity, transient versus continuous processes, etc. I will finally present some possible perspectives for the development of future models.

  10. A Primer on Unifying Debris Disk Morphologies

    Science.gov (United States)

    Lee, Eve J.; Chiang, Eugene

    2016-08-01

    A “minimum model” for debris disks consists of a narrow ring of parent bodies, secularly forced by a single planet on a possibly eccentric orbit, colliding to produce dust grains that are perturbed by stellar radiation pressure. We demonstrate how this minimum model can reproduce a wide variety of disk morphologies imaged in scattered starlight. Five broad categories of disk shape can be captured: “rings,” “needles,” “ships-and-wakes,” “bars,” and “moths (a.k.a. fans),” depending on the viewing geometry. Moths can also sport “double wings.” We explain the origin of morphological features from first principles, exploring the dependence on planet eccentricity, disk inclination dispersion, and the parent body orbital phases at which dust grains are born. A key determinant in disk appearance is the degree to which dust grain orbits are apsidally aligned. Our study of a simple steady-state (secularly relaxed) disk should serve as a reference for more detailed models tailored to individual systems. We use the intuition gained from our guidebook of disk morphologies to interpret, informally, the images of a number of real-world debris disks. These interpretations suggest that the farthest reaches of planetary systems are perturbed by eccentric planets, possibly just a few Earth masses each.

  11. The Herschel Cold Debris Disks

    CERN Document Server

    Gaspar, Andras

    2013-01-01

    The Herschel "DUst around NEarby Stars (DUNES)" survey has found a number of debris disk candidates that are apparently very cold, with temperatures near 22K. It has proven difficult to fit their spectral energy distributions with conventional models for debris disks. Given this issue we carefully examine the alternative explanation, that the detections arise from confusion with IR cirrus and/or background galaxies that are not physically associated with the foreground star. We find that such an explanation is consistent with all of these detections.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Marine Debris Research, Prevention, and Reduction Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Debris Research, Prevention, and Reduction Act legally establishes the National Oceanic and Atmospheric Administration's (NOAA) Marine Debris Program. The...

  14. Space Debris Elimination (SpaDE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The amount of debris in low Earth orbit (LEO) has increased rapidly over the last twenty years. This prevalence of debris increases the likelihood of cascading...

  15. An Evolution Model of Space Debris Environment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Various types of models including engineering models andevolution models have been developed to understand space debris environment since 1960s. Evolution model, consisting of a set of supporting models such as Launch Model, Breakup Model and Atmosphere Model, can reliably predicts the evolution of space debris environment. Of these supporting models, Breakup Model is employed to describe the distribution of debris and debris cloud during a explosion or collision case which is one of the main factors affecting the amount of total space debris. An analytical orbit debris environment model referred to as the “Particles-In-Boxes" model has been introduced. By regarding the orbit debris as the freedom particles running in the huge volume, the sources and sinks mechanism is established. Then the PIB model is expanded to the case of multiple-species in multiple-tier system. Combined with breakup model, the evolution of orbit debris environment is predicted.

  16. NASA Orbital Debris Requirements and Best Practices

    Science.gov (United States)

    Hull, Scott

    2014-01-01

    Limitation of orbital debris accumulation is an international and national concern, reflectedin NASA debris limitation requirements. These requirements will be reviewed, along with some practices that can be employed to achieve the requirements.

  17. DebriSat Project Update and Planning

    Science.gov (United States)

    Sorge, M.; Krisko, P. H.

    2016-01-01

    DebriSat Reporting Topics: DebriSat Fragment Analysis Calendar; Near-term Fragment Extraction Strategy; Fragment Characterization and Database; HVI (High-Velocity Impact) Considerations; Requirements Document.

  18. Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China

    NARCIS (Netherlands)

    Tang, C.; Rengers, N.; Asch, Th.W.J. van; Yang, Y.H.; Wang, G.F.

    2011-01-01

    On 7 August 2010, catastrophic debris flows were triggered by a rainstorm in the catchments of the Sanyanyu and Luojiayu torrents, Zhouqu County, Gansu Province northwestern China. These two debris flows originated shortly after a rainstorm with an intensity of 77.3 mm h−1 and transported a total vo

  19. Local fallout from nuclear test detonations. Volume 2. Compilation of fallout patterns and related test data. Supplement. Foreign nuclear tests. Sanitized

    Energy Technology Data Exchange (ETDEWEB)

    Morgenthau, M.; Showers, R.L.

    1964-10-01

    The available fallout patterns and related test data for nuclear weapon tests conducted by the United Kingdom, the Republic of France, and the Union of Soviet Socialist Republics, are included in this supplement to NDL-TR-34. The related test data for the British and French tests include: date and time of detonation, location of test site, total yield, fission yield, type of burst and placement, height of burst, cloud-top and -bottom heights, crater data, and wind information up to nuclear cloud-top height. No fallout patterns are available for any of the Soviet detonations. The list of Soviet detonations, which is as comprehensive as possible, contains the chronological order of the detonations, date, yield, type of burst and location of test site.

  20. A Search for Optically Faint GEO Debris

    Science.gov (United States)

    2011-09-01

    similar filter with the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American...Examples are the results from the European Space Debris Facility in the Canary Islands, MODEST (the Michigan orbital DEbris Survey Telescope at Cerro ...filter with the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American

  1. Drift simulation of MH370 debris using superensemble techniques

    Science.gov (United States)

    Jansen, Eric; Coppini, Giovanni; Pinardi, Nadia

    2016-07-01

    On 7 March 2014 (UTC), Malaysia Airlines flight 370 vanished without a trace. The aircraft is believed to have crashed in the southern Indian Ocean, but despite extensive search operations the location of the wreckage is still unknown. The first tangible evidence of the accident was discovered almost 17 months after the disappearance. On 29 July 2015, a small piece of the right wing of the aircraft was found washed up on the island of Réunion, approximately 4000 km from the assumed crash site. Since then a number of other parts have been found in Mozambique, South Africa and on Rodrigues Island. This paper presents a numerical simulation using high-resolution oceanographic and meteorological data to predict the movement of floating debris from the accident. Multiple model realisations are used with different starting locations and wind drag parameters. The model realisations are combined into a superensemble, adjusting the model weights to best represent the discovered debris. The superensemble is then used to predict the distribution of marine debris at various moments in time. This approach can be easily generalised to other drift simulations where observations are available to constrain unknown input parameters. The distribution at the time of the accident shows that the discovered debris most likely originated from the wide search area between 28 and 35° S. This partially overlaps with the current underwater search area, but extends further towards the north. Results at later times show that the most probable locations to discover washed-up debris are along the African east coast, especially in the area around Madagascar. The debris remaining at sea in 2016 is spread out over a wide area and its distribution changes only slowly.

  2. Applying Knowledge from Terrestrial Debris-Covered Glaciers to Constrain the Evolution of Martian Debris-Covered Ice

    Science.gov (United States)

    Koutnik, M. R.; Pathare, A. V.; Todd, C.; Waddington, E.; Christian, J. E.

    2016-09-01

    We will discuss the application of terrestrial knowledge on debris emplacement, the effects of debris on glacier-surface topography, debris transport by ice flow, deformation of debris-laden ice, and atmosphere-glacier feedbacks to Mars ice.

  3. Variability in rainfall threshold for debris flow after the Chi-Chi earthquake in central Taiwan, China

    Institute of Scientific and Technical Information of China (English)

    C. L. SHIEH; Y. S. CHEN; Y. J. TSAI; J. H. WU

    2009-01-01

    The purpose of this study is to analyze variability in rainfall threshold for debris flow (critical rainfall for debris flow triggering) after the ML 7.3 Chi-Chi earthquake in central Taiwan in 1999.Two study sites with different geological conditions were surveyed in the earthquake area. Streambed surveys were conducted to continuously monitor debris flows between 1999 and 2006. During the 7-year study period, every debris flow event was identified, and the streambed characterized. Results show that the rainfall threshold for debris flow was remarkably lower just after the Chi-ChiEarthquake, but gradually recovered. To date, this rainfall threshold is still lower than the original level prior to the earthquake. This variability in rainfall threshold is closely related to the amount of sediment material in the initiation area of debris flow, which increased rapidly due to landslides resulting from the earthquake. With the increase in sediment material, the rainfall threshold was lowered severely during the first year following the Chi-Chi earthquake. However, heavy rainfalls mobilized the sediment material, causing debris flows and transporting sediment downstream. With the decrease in sediment material, the rainfall threshold recovered gradually over time. Furthermore,debris flows occurred only in the subbasins that had sufficient sediment material to cause significant movement. Hence, these results confirm that the sediment material in the initiation area of debris flow is a crucial component of the rainfall threshold for debris flow.

  4. Magnitude-frequency characteristics and preparatory factors for spatial debris-slide distribution in the northern Faroe Islands

    DEFF Research Database (Denmark)

    Dahl, Mads-Peter Jakob; Jensen, Niels H.; Veihe, Anita

    2013-01-01

    the magnitude and frequency of their debris-slide origins as well as identifying which preparatory factors are responsible for the spatial debris-slide distribution in the landscape. For that purpose a debris-slide inventory was generated from aerial photo interpretation (API), fieldwork and anecdotal sources......, covering a 159 km(2) study area in the northern Faroe Islands. A magnitude-cumulative frequency (MCF) curve was derived to predict magnitude dependant debris-slide frequencies, while preparatory factors responsible for spatial debris-slide distribution were quantified through GIS-supported discriminant...... function analysis (DFA). Nine factors containing geological (lithology, dip), geomorphological (slope angle, altitude, aspect; plan and profile curvature) and land use (infield/outfield, sheep density) information were included in the multivariate analysis. Debris-slides larger than 100 m(2) with magnitude...

  5. La Lavina del Valle Central (Costa Rica): ¿lahar o Debris Avalanche?

    OpenAIRE

    Hidalgo, Paulo J.; Guillermo E. Alvarado; Linkimer, Lepolt

    2011-01-01

    La denominada lavina del Valle Central, constituida por bloques de lava mal seleccionados y flo-tantes en una matriz de lodos volcánicos, había sido interpretada genéticamente como un debris flow (lahar). Este trabajo trata de discutir algunas características que sugieren que el depósito se originó en un debris avalancheque se transformó en un debris flow (lahar). Se identificaron anfiteatros de avalancha en los estratovolcanes extintos del sector occidental del macizo del Irazú, en donde la ...

  6. An Experimental Study on the Nuclear Fuel Debris Filtering Efficiency Using Wire Debris

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joon-Kyoo; Kwon, Oh-Joon; Lee, Tae-Kwon; Park, Nam-Gyu; Kim, Jae-Ik [KEPCO NF, Daejeon (Korea, Republic of)

    2014-10-15

    If this debris vibrates over a long period of time, the cladding tubes could wear out. Especially, the wire types of debris from the tools during the plant maintenance operations can induce worn hole or wear scar on the fuel rods and may be make severe damage. Most of failures due to debris are observed under the first grid from the bottom of fuel assembly. In order to mitigate this defect, the fuel vendor have developed various anti-debris grids, such as protective grid or debris filtering bottom grid, which is located just above the bottom nozzle. The vendors have performed the debris filtering test to evaluate the efficiency of these grids. KEPCO NF (KEPCO Nuclear fuel) also has carried out the debris filtering test for the fuel assembly with protective grid. Some major design parameters, such as the maximum debris passable size or grid axial location, which affect the debris filtering capacity are found out thorough the test. This paper will discuss the filtering efficiency according to the relative dimensions of wire debris specimens and the effects of the specimen dimensions through simulation tests. The relative dimensions could be useful to develop the debris filtering grid. This study discussed the filtering efficiency according to the relative dimensions of wire debris specimens through simulation tests. The wire debris is used since the debris is more useful to evaluate debris filtering efficiency.

  7. Upscaling the Use of Fallout Radionuclides in Soil Erosion and Sediment Budget Investigations: Addressing the Challenge

    Directory of Open Access Journals (Sweden)

    D.E. Walling

    2014-09-01

    Full Text Available The application of fallout radionuclides in soil erosion investigations and related sediment budget studies has provided a widely used tool for improving understanding of soil erosion and sediment transfer processes. However, most studies using fallout radionuclides undertaken to date have focussed on small areas. This focus on small areas reflects both the issues addressed and practical constraints associated with sample collection and analysis. Increasing acceptance of the important role of fine sediment in degrading aquatic habitats and in the transfer and fate of nutrients and contaminants within terrestrial and fluvial systems has emphasised the need to consider larger areas and the catchment or regional scale. The need to upscale existing approaches to the use of fallout radionuclides to larger areas represents an important challenge. This contribution provides a brief review of existing and potential approaches to upscaling the use of fallout radionuclides and presents two examples where such approaches have been successfully applied. These involve a national scale assessment of soil erosion rates in England and Wales based on 137Cs measurements and an investigation of the sediment budgets of three small/intermediate-size catchments in southern Italy.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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).

  10. MX MPS deployment, an on-site fallout evaluation. Final report 12 Jul-29 Dec 78

    Energy Technology Data Exchange (ETDEWEB)

    Craver, R.H.; McGahan, J.T.; Muller, E.

    1978-12-29

    This report addresses the probable extent and severity of the fallout hazard associated with a massive hypothetical attack against an MPS Deployment of the MX missile in the Nevada Model Area. It contains descriptions of attack scenarios, site modeling, methodology for calculating and depicting the distribution of fallout, and quantitative estimates of the severity of the hazard. Forty separate wind samples taken over a twelve-month period are used to assess the variability of the distribution of fallout resulting from an attack of several thousand surface burst weapons at the Nevada site. Fallout intensities are determined at 177 monitor points throughout the potential deployment area; time histories of dose rate buildup and decay are presented and discussed with respect to operational implications. Key factors are parameterized to permit comparison of a range of design factors and logistical considerations. Key findings are presented in condensed form including several illustrative examples chosen to quantify the practical aspects of operating in a radiation environment and to assist in the development of a balanced system design.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Christian J., E-mail: zinosanders@yahoo.com [Universidade Federal de Fluminense (UFF), Departamento de Geoquimica, Outeiro de Sao Joao Baptista s/n, Morro do Valonguinho Centro, Niteroi, RJ (Brazil); Smoak, Joseph M. [University of South Florida (USF), Environmental Science, St. Petersburg, FL (United States); Cable, Peter H. [Tulane University, Department of Earth and Environmental Sciences, New Orleans, LA (United States); Patchineelam, Sambasiva R. [Universidade Federal de Fluminense (UFF), Departamento de Geoquimica, Outeiro de Sao Joao Baptista s/n, Morro do Valonguinho Centro, Niteroi, RJ (Brazil); Sanders, Luciana M. [Istituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro 22780 (Brazil)

    2011-12-15

    Total {sup 210}Pb and {sup 7}Be fallout rates were measured on the coastal region of Niteroi, Brazil. The monthly depositional flux of {sup 210}Pb and {sup 7}Be varied by a factor of 26, from 1.7 to 43.3 mBq cm{sup -2} year{sup -1} and {approx}27, from 7.5 to 203.5 mBq cm{sup -2} year{sup -1}, respectively. The relatively large oscillations in the depositional flux of {sup 210}Pb at this study site were likely due to variations in air mass sources, while the {sup 7}Be fluctuations may be driven by a combination of weather conditions. Local geology could support the periodic high fluxes of {sup 210}Pb from continental air masses, as shifting oceanic wind sources were affirmed by the uncorrelated {sup 210}Pb and {sup 7}Be fallout activities and {sup 7}Be/{sup 210}Pb ratios. The {sup 210}Pb atmospheric deposition was found to be in agreement with local sediment inventories, an important consideration in geochemical studies that estimate sedimentation processes. - Highlights: > Fallout rates of {sup 210}Pb and {sup 7}Be indicate depositional flux during a 12-month period. > Oscillations in {sup 210}Pb and {sup 7}Be fallout are driven by geology ({sup 210}Pb) and weather. > Regional trends in {sup 7}Be and {sup 210}Pb fluxes used in geochemical processes.

  12. THE CONSEQUENCES OF INGESTION BY MAN OF REAL AND SIMULATED FALLOUT,

    Science.gov (United States)

    ingested radioactivity was measured by whole body counting using the gamma-ray spectrometer at the Argonne Cancer Research Hospital. An average of 3 per...strontium, cesium and barium following ingestion of fallout, and retention of the radionuclides of these elements. (Author)

  13. Debris flows and cosmogenic catchment wide denudation rates

    Science.gov (United States)

    Kober, F.; Hippe, K.; Salcher, B.; Ivy-Ochs, S.; Kubik, P. W.; Christl, M.; Wacker, L.

    2012-04-01

    One of the basic question in alpine Quantitative Geomorphology is: Are widely measured cosmogenic nuclide-derived denudation rates in alpine catchments truly representative for the whole catchment at any given time? Or in contrast can they vary markedly in response to extreme events and perturbations? And if such perturbations affect cosmogenic nuclide-derived denudation rates then what bias can occur when such denudation rates are compared with sediment yield or thermochronological data or to various morphometric parameters, such as slope, mean elevation or uplift rates as potential controlling factors? We present 10Be and 14C results measured in sand samples from an active river channel from a single catchment (upper Aare), in the Swiss Alps (up to monthly sampling between 2008 to 2011). Our goal was to establish a time series to see if extreme events (such as landslides or debris flows) do have a discernible effect on derived denudation rates. The admixture of sediment of debris flows in 2009, originating upstream of the sampling spot, began to have a marked effect on 10Be concentrations and thus catchment wide denudation rates that are assumed to be in a long-term range mode prior to 2009. In summer of 2010, several extreme debris flows were recorded in the studied catchment. Samples taken document a doubling of denudation rates over the values determined from 2008. These cosmogenic nuclide data clearly demonstrate the impact of episodic events on sediment flux and the related perturbation of catchment wide denudation rates. We have recently expanded this dataset into 2011, with i) a spatial sub-sampling of debris flow and non-debris flow catchment compartments and ii) including again a major debris flow event in early autumn 2011. These data will be presented at the conference. Never-the-less the fact that the CWDR's only doubled does suggest a certain robustness in the method beyond a certain catchment size. In addition to the 10Be data, in situ 14C

  14. Secondary crater-initiated debris flow on the Moon

    Science.gov (United States)

    Martin-Wells, K. S.; Campbell, D. B.; Campbell, B. A.; Carter, L. M.; Fox, Q.

    2017-07-01

    In recent work, radar circular polarization echo properties have been used to identify secondary craters without distinctive ;secondary; morphologies. Because of the potential for this method to improve our knowledge of secondary crater populations-in particular the effect of secondary populations on crater-derived ages based on small craters-it is important to understand the origin of radar polarization signatures associated with secondary impacts. In this paper, we utilize Lunar Reconnaissance Orbiter Camera photographs to examine the geomorphology of secondary craters with radar circular polarization ratio enhancements. Our investigation reveals evidence of dry debris flow with an impact melt component at such secondary craters. We hypothesize that these debris flows were initiated by the secondary impacts themselves, and that they have entrained blocky material ejected from the secondaries. By transporting this blocky material downrange, we propose that these debris flows (rather than solely ballistic emplacement) are responsible for the tail-like geometries of enhanced radar circular polarization ratio associated with the secondary craters investigated in this work. Evidence of debris flow was observed at both clustered and isolated secondary craters, suggesting that such flow may be a widespread occurrence, with important implications for the mixing of primary and local material in crater rays.

  15. Carbon Monoxide Emissions in Middle Aged Debris Disks

    Science.gov (United States)

    Henderson, Morgan; Gorti, Uma; Hales, Antonio; Carpenter, John M.; Hughes, A. Meredith

    2017-01-01

    Circumstellar disks greater than 10 Myr old, referred to as debris disks, are expected to be gas poor. The original gas and dust in these disks is thought to be accreted onto the host stars, used up in the formation of planets and other bodies, or blown out of the disks via stellar radiation. However, recent ALMA observations at millimeter wavelengths have led to the detection of carbon monoxide (J=2-1) emission in a few debris disks, prompting further investigation.Using ALMA data, two separate models of gas genesis were tested against observations of the CO emissions in the disks around HIP 73145, HIP 76310, and HIP 84881 in the Upper Sco association. One of these models was built on the hypothesis that the gas in these debris disks is left over from stellar formation and has persisted over uncommonly long periods of time. The other model is built on the hypothesis that this gas is of secondary nature, produced by collisions between planetary bodies in the debris disks. Model emissions were calculated using the Line Modeling Engine (LIME) radiative transfer code and were compared with observational data to infer gas masses under both production scenarios. The implications of the masses of carbon monoxide in the disks suggested by each of the two models are discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Patric E-mail: patric.lindahl@radfys.lu.se; Roos, Per; Eriksson, Mats; Holm, Elis

    2004-07-01

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

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

    Science.gov (United States)

    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.

  18. Space Tourism: Orbital Debris Considerations

    Science.gov (United States)

    Mahmoudian, N.; Shajiee, S.; Moghani, T.; Bahrami, M.

    2002-01-01

    Space activities after a phase of research and development, political competition and national prestige have entered an era of real commercialization. Remote sensing, earth observation, and communication are among the areas in which this growing industry is facing competition and declining government money. A project like International Space Station, which draws from public money, has not only opened a window of real multinational cooperation, but also changed space travel from a mere fantasy into a real world activity. Besides research activities for sending man to moon and Mars and other outer planets, space travel has attracted a considerable attention in recent years in the form of space tourism. Four countries from space fairing nations are actively involved in the development of space tourism. Even, nations which are either in early stages of space technology development or just beginning their space activities, have high ambitions in this area. This is worth noting considering their limited resources. At present, trips to space are available, but limited and expensive. To move beyond this point to generally available trips to orbit and week long stays in LEO, in orbital hotels, some of the required basic transportations, living requirements, and technological developments required for long stay in orbit are already underway. For tourism to develop to a real everyday business, not only the price has to come down to meaningful levels, but also safety considerations should be fully developed to attract travelers' trust. A serious hazard to space activities in general and space tourism in particular is space debris in earth orbit. Orbiting debris are man-made objects left over by space operations, hazardous to space missions. Since the higher density of debris population occurs in low earth orbit, which is also the same orbit of interest to space tourism, a careful attention should be paid to the effect of debris on tourism activities. In this study, after a

  19. The fast debris evolution model

    Science.gov (United States)

    Lewis, H. G.; Swinerd, G. G.; Newland, R. J.; Saunders, A.

    2009-09-01

    The 'particles-in-a-box' (PIB) model introduced by Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] removed the need for computer-intensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation's coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FADE), employs a first-order differential equation to describe the rate at which new objects ⩾10 cm are added and removed from the environment. Whilst Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FADE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model. The FADE model has been implemented as a client-side, web-based service using JavaScript embedded within a HTML document. Due to the simple nature of the algorithm, FADE can deliver the results of future projections immediately in a graphical format, with complete user-control over key simulation parameters. Historical and future projections for the ⩾10 cm LEO debris environment under a variety of different scenarios are possible, including business as usual, no future launches, post-mission disposal and remediation. A selection of results is presented with comparisons with predictions made using the DAMAGE environment model

  20. Space Debris Alert System for Aviation

    Science.gov (United States)

    Sgobba, Tommaso

    2013-09-01

    Despite increasing efforts to accurately predict space debris re-entry, the exact time and location of re-entry is still very uncertain. Partially, this is due to a skipping effect uncontrolled spacecraft may experience as they enter the atmosphere at a shallow angle. Such effect difficult to model depends on atmospheric variations of density. When the bouncing off ends and atmospheric re-entry starts, the trajectory and the overall location of surviving fragments can be precisely predicted but the time to impact with ground, or to reach the airspace, becomes very short.Different is the case of a functional space system performing controlled re-entry. Suitable forecasts methods are available to clear air and maritime traffic from hazard areas (so-called traffic segregation).In US, following the Space Shuttle Columbia accident in 2003, a re-entry hazard areas location forecast system was putted in place for the specific case of major malfunction of a Reusable Launch Vehicles (RLV) at re-entry. The Shuttle Hazard Area to Aircraft Calculator (SHAAC) is a system based on ground equipment and software analyses and prediction tools, which require trained personnel and close coordination between the organization responsible for RLV operation (NASA for Shuttle) and the Federal Aviation Administration. The system very much relies on the operator's capability to determine that a major malfunction has occurred.This paper presents a US pending patent by the European Space Agency, which consists of a "smart fragment" using a GPS localizer together with pre- computed debris footprint area and direct broadcasting of such hazard areas.The risk for aviation from falling debris is very remote but catastrophic. Suspending flight over vast swath of airspace for every re-entering spacecraft or rocket upper stage, which is a weekly occurrence, would be extremely costly and disruptive.The Re-entry Direct Broadcasting Alert System (R- DBAS) is an original merging and evolution of the Re

  1. Losses of Sr/sup 90/, Sr/sup 89/, and I/sup 131/ from fallout-contaminated plants

    Energy Technology Data Exchange (ETDEWEB)

    Martin, W.E.

    1964-11-01

    During the early period following local fallout, and during periods of maximal worldwide fallout, the entry of radionuclides into terrestrial food-chains is due primarily to the external contamination of plants and secondarily to the uptake of radionuclides from contaminated soil. Studies were undertaken to estimate the rates of radionuclide loss from fallout-contaminated vegetation and hence from the diets of herbivores living in a fallout field. On the fifth, fifteenth, thirtieth, and sixtieth days after an underground nuclear explosion (Operation Sedan) at the Nevada Test Site, plant samples were collected from twenty representative locations in the fallout field and analyzed to determined the concentrations (pc/g dry wt) of /sup 90/Sr, /sup 89/Sr, and /sup 131/I at the times of collections. While the radioactive half lives of /sup 90/Sr, /sup 89/Sr, and /sup 131/I are approximately 27.7 years, 53 days, and 8.04 days respectively, their average effective half-lives on fallout-contaminated plants, during the period from 5 to 30 days after the detonation, were 27.8 days, 17.8 days, and 5.0 days respectively. Losses of /sup 90/Sr were attributed to radioactive decay and to the removal of fallout particles and foliage by wind and/or other mechanical disturbances. Losses of /sup 90/Sr and /sup 89/Sr were attributed to radioactive decay and to the removal of fallout particles and foliage by wind and/or other mechanical disturbances. Losses of /sup 131/I were attributed to radioactive decay, to mechanical disturbance, and to the vaporization of /sup 131/I from the fallout particles retained on foliage.

  2. Combined use of fallout radionuclides and stable isotopes for investigating soil erosion processes in a Moroccan watershed

    Science.gov (United States)

    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

  3. Comparison of space debris estimates

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.; Judd, O.P.; Naka, R.F.

    1996-10-01

    Debris is thought to be a hazard to space systems through impact and cascading. The current environment is assessed as not threatening to defense systems. Projected reductions in launch rates to LEO should delay concerns for centuries. There is agreement between AFSPC and NASA analyses on catalogs and collision rates, but not on fragmentation rates. Experiments in the laboratory, field, and space are consistent with AFSPC estimates of the number of fragments per collision. A more careful treatment of growth rates greatly reduces long-term stability issues. Space debris has not been shown to be an issue in coming centuries; thus, it does not appear necessary for the Air Force to take additional steps to mitigate it.

  4. Debris flow study in Malaysia

    Science.gov (United States)

    Bahrin Jaafar, Kamal

    2016-04-01

    The phenomenon of debris flow occurs in Malaysia occasionally. The topography of Peningsular Malysia is characterized by the central mountain ranges running from south to north. Several parts of hilly areas with steep slopes, combined with high saturation of soil strata that deliberately increase the pore water pressure underneath the hill slope. As a tropical country Malaysia has very high intensity rainfall which is triggered the landslide. In the study area where the debris flow are bound to occur, there are a few factors that contribute to this phenomenon such as high rainfall intensity, very steep slope which an inclination more than 35 degree and sandy clay soil type which is easily change to liquidity soil. This paper will discuss the study of rainfall, mechanism, modeling and design of mitigation measure to avoid repeated failure in future in same area.

  5. DebriSat Laboratory Analyses

    Science.gov (United States)

    2015-01-05

    Semiquantitative elemental composition. – Elemental mapping and line scans. • Fourier Transform Infrared ( FTIR ) spectroscopy – Identification of chemical...Transform Infrared ( FTIR ) spectroscopy – Nicolet 6700 spectrometer. – Harrick Scientific “praying mantis” diffuse reflectance accessory. • Qualitative...VIS-NIR Spectroscopy Dianna Alaan © The Aerospace Corporation 2015 DebriSat Laboratory Analyses 5 January, 2015 Paul M. Adams1, Zachary Lingley2

  6. ORDEM 3.0 and MASTER-2009 Modeled Small Debris Population Comparison

    Science.gov (United States)

    Krisko, P. H.; Flegel, S.

    2014-01-01

    The latest versions of the two premier orbital debris engineering models, NASA's ORDEM 3.0 and ESA's MASTER-2009, have been publically released. Both models have gone through significant advancements since inception, and now represent the state-of-the-art in orbital debris knowledge of their respective agencies. The purpose of these models is to provide satellite designers/operators and debris researchers with reliable estimates of the artificial debris environment in low Earth orbit (LEO) to geosynchronous orbit (GEO). The small debris environment within the size range of 1 mm to 1 cm is of particular interest to both human and robotic spacecraft programs, particularly in LEO. These objects are much more numerous than larger trackable debris and can have enough momentum to cause significant, if not catastrophic, damage to spacecraft upon impact. They are also small enough to elude routine detection by existing observation systems (radar and telescope). Without reliable detection the modeling of these populations has always coupled theoretical origins with supporting observational data in different degrees. In this paper, we present and detail the 1 mm to 1 cm orbital debris populations from both ORDEM 3.0 and MASTER-2009 in LEO. We review population categories: particle sources for MASTER-2009, particle densities for ORDEM 3.0. We describe data sources and their uses, and supporting models. Fluxes on spacecraft for chosen orbits are also presented and discussed within the context of each model.

  7. Bed Stability and Debris Flow Erosion: A Dynamic "Shields Criterion" Associated with Bed Structure

    Science.gov (United States)

    Longjas, A.; Hill, K. M.

    2015-12-01

    Debris flows are mass movements that play an important role in transporting sediment from steep uplands to rivers at lower slopes. As the debris flow moves downstream, it entrains materials such as loose boulders, gravel, sand and mud deposited locally by shorter flows such as slides and rockfalls. To capture the conditions under which debris flows entrain bed sediment, some models use something akin to the Shields' criterion and an excess shear stress of the flow. However, these models typically neglect granular-scale effects in the bed which can modify the conditions under which a debris flow is erosional or depositional. For example, it is well known that repeated shearing causes denser packing in loose dry soils, which undoubtedly changes their resistance to shear. Here, we present laboratory flume experiments showing that the conditions for entrainment by debris flows is significantly dependent on the aging of an erodible bed even for narrowly distributed spherical particles. We investigate this quantitatively using particle tracking measurements to quantify instantaneous erosion rates and the evolving bed structure or "fabric". With progressive experiments we find a signature that emerges in the bed fabric that is correlated with an increasing apparent "fragility" of the bed. Specifically, a system that is originally depositional may become erosional after repeated debris flow events, and an erodible bed becomes increasingly erodible with repeated flows. We hypothesize that related effects of bed aging at the field scale may be partly responsible for the increasing destructiveness of secondary flows of landslides and debris flows.

  8. The 13 August 2010 catastrophic debris flows after the 2008 Wenchuan earthquake, China

    Directory of Open Access Journals (Sweden)

    Q. Xu

    2012-01-01

    Full Text Available From 12 to 14 August 2010, heavy rainstorms occurred in the Sichuan province in SW China in areas which were affected by the 2008 Wenchuan Earthquake, inducing catastrophic debris flows. This disaster is named as "the 8.13 debris flows". The results of the research presented in this paper show that the 8.13 debris flows are characterized by a simultaneous occurrence, rapid-onsets, destructive impacts, and disaster chain effects. They are located along the seismic fault, because the source materials mainly originate from loose deposits of landslides which were triggered by the Wenchuan Earthquake. The presence of large amounts of these loose materials on the slopes and the development of high intensity rainfall events are the main causes for the formation of these debris flows. The study of the 8.13 debris flows can provide a benchmark for the analysis of the long-term evolution of these debris flows in order to make proper engineering decisions. A flexible drainage system is proposed in this paper as a preventive measure to mitigate the increasing activity of these debris flows in the earthquake-affected area.

  9. An alternative origin for debris rings of planetesimals

    CERN Document Server

    Nayakshin, Sergei

    2012-01-01

    Core Accretion, the most widely accepted scenario for planet formation, postulates existence of km-sized solid bodies, called planetesimals, arranged in a razor-thin disc in the earliest phases of planet formation. In the Tidal Downsizing hypothesis, an alternative scenario for formation of planets, grain growth, sedimentation and formation of planetary cores occur inside dense and massive gas clumps formed in the outer cold disc by gravitational instability. As a clump migrates inward, tidal forces of the star remove all or most of the gas from the clump, downsizing it to a planetary mass body. Here we argue that such a clump may form not only the planetary core but also numerous smaller bodies. As an example, we consider the simplest case of bodies on circular orbits around the planetary core in the centre of the gas clump. Bodies smaller than 1 km suffer a strong enough aerodynamic drag, spiral in and accrete onto the solid core rapidly; bodies in the planetesimal size range lose their centrifugal support ...

  10. Identification of Globular Cluster Stars in RAVE data II: Extended tidal debris around NGC 3201

    CERN Document Server

    Anguiano, B; Freeman, K; Da Costa, G S; Zwitter, T; Quillen, A C; Zucker, D B; Navarro, J F; Kunder, A; Siebert, A; Wyse, R F G; Grebel, E K; Kordopatis, G; Gibson, B K; Seabroke, G; Sharma, S; Wojno, J; Bland-Hawthorn, J; Parker, Q A; Steinmetz, M; Boeche, C; Gilmore, G; Bienayme, O; Reid, W; Watson, F

    2016-01-01

    We report the identification of extended tidal debris potentially associated with the globular cluster NGC 3201, using the RAVE catalogue. We find the debris stars are located at a distance range of 1-7 kpc based on the forthcoming RAVE distance estimates. The derived space velocities and integrals of motion show interesting connections to NGC 3201, modulo uncertainties in the proper motions. Three stars, which are among the 4 most likely candidates for NGC 3201 tidal debris, are separated by 80 degrees on the sky yet are well matched by the 12 Gyr, [Fe/H] = -1.5 isochrone appropriate for the cluster. This is the first time tidal debris around this cluster has been reported over such a large spatial extent, with implications for the cluster$'$s origin and dynamical evolution.

  11. Reevaluation of tsunami formation by debris avalanche at Augustine Volcano, Alaska

    Science.gov (United States)

    Waythomas, C.F.

    2000-01-01

    Debris avalanches entering the sea at Augustine Volcano, Alaska have been proposed as a mechanism for generating tsunamis. Historical accounts of the 1883 eruption of the volcano describe 6- to 9-meter-high waves that struck the coastline at English Bay (Nanwalek), Alaska about 80 kilometers east of Augustine Island. These accounts are often cited as proof that volcanigenic tsunamis from Augustine Volcano are significant hazards to the coastal zone of lower Cook Inlet. This claim is disputed because deposits of unequivocal tsunami origin are not evident at more than 50 sites along the lower Cook Inlet coastline where they might be preserved. Shallow water (Augustine Island, in the run-out zone for debris avalanches, limits the size of an avalanche-caused wave. If the two most recent debris avalanches, Burr Point (A.D. 1883) and West Island (Augustine Volcano appears minor, unless a very large debris avalanche occurs at high tide.

  12. Forming Gaps in Debris Disks with Fewer Planets via Planet Migration

    Science.gov (United States)

    Morrison, Sarah J.; Kratter, Kaitlin M.

    2016-10-01

    Debris disks across a wide range of ages can possess wide gaps of several AU or more; these gaps have been attributed to the presence of multiple planets. While at least two planets are likely needed for maintaining the edges of such gaps, large gaps may require more than two in more dynamically packed configurations to be able to have cleared material within the gap in the present day. As an alternative to currently packed planets occupying gaps in debris disks, we assess whether planetesimal and dynamical instability-driven planet migration could produce wide gaps with lower mass, fewer planets on relevant timescales to be consistent with the observed properties of debris disk systems. We also discuss implications for the disk properties in which these mechanisms could operate within the broader evolutionary context linking planets, debris disks, and the protoplanetary disks from which they originated.

  13. Process Knowledge Summary Report for Materials and Fuels Complex Contact-Handled Transuranic Debris Waste

    Energy Technology Data Exchange (ETDEWEB)

    R. P. Grant; P. J. Crane; S. Butler; M. A. Henry

    2010-02-01

    This Process Knowledge Summary Report summarizes the information collected to satisfy the transportation and waste acceptance requirements for the transfer of transuranic (TRU) waste between the Materials and Fuels Complex (MFC) and the Advanced Mixed Waste Treatment Project (AMWTP). The information collected includes documentation that addresses the requirements for AMWTP and the applicable portion of their Resource Conservation and Recovery Act permits for receipt and treatment of TRU debris waste in AMWTP. This report has been prepared for contact-handled TRU debris waste generated by the Idaho National Laboratory at MFC. The TRU debris waste will be shipped to AMWTP for purposes of supercompaction. This Process Knowledge Summary Report includes information regarding, but not limited to, the generation process, the physical form, radiological characteristics, and chemical contaminants of the TRU debris waste, prohibited items, and packaging configuration. This report, along with the referenced supporting documents, will create a defensible and auditable record for waste originating from MFC.

  14. Space Debris: il problema dei rifiuti spaziali

    OpenAIRE

    Michele Dussi

    2008-01-01

    Space Debris: the space garbage problemThe dramatic growth in space activities since 1957 has generated a large amount of “in-orbit garbage”, namely space-debris. Many of these are potentially dangerous for space vehicles and/or for the people on Earth. In an acceptable space security framework, amajor role is reserved to cooperative space debris monitoring in order to prevent and to mitigate the effects of the problem.

  15. Best Mitigation Paths To Effectively Reduce Earth's Orbital Debris

    Science.gov (United States)

    Wiegman, Bruce M.

    2009-01-01

    This slide presentation reviews some ways to reduce the problem posed by debris in orbit around the Earth. It reviews the orbital debris environment, the near-term needs to minimize the Kessler syndrome, also known as collisional cascading, a survey of active orbital debris mitigation strategies, the best paths to actively remove orbital debris, and technologies that are required for active debris mitigation.

  16. Modeling Experiment of Break of Debris-Flow Dam

    Institute of Scientific and Technical Information of China (English)

    CHENG Zunlan; GENG Xueyong; DANG Chao; LIU Jingjing

    2007-01-01

    Glaciers are extensively developed in the southwest of Tibet and the moraines are widely distributed with large depth. Large-scale debris flows are often reported which blocked rivers and formed dams. In this paper, seven large debris flows in four valleys are discussed, among which five dams developed. 13 sets of experiments have been conducted in laboratory to simulate the formation and failure of the dam. Finally, a model of dam failure is proposed and a formula is established to calculate the flood discharge:Q = kbhhk/T (B)/LG0.41, where bk is the outlet width of the dam atthe original water level, ht the erosive depth, T the time fromoverflow to final state of failure, the average width of lake; L thelength of the lake, and G the total potential energy of the water inthe lake.

  17. Variations in debris distribution and thickness on Himalayan debris-covered glaciers

    Science.gov (United States)

    Gibson, Morgan; Rowan, Ann; Irvine-Fynn, Tristram; Quincey, Duncan; Glasser, Neil

    2016-04-01

    Many Himalayan glaciers are characterised by extensive supraglacial debris coverage; in Nepal 33% of glaciers exhibit a continuous layer of debris covering their ablation areas. The presence of such a debris layer modulates a glacier's response to climatic change. However, the impact of this modulation is poorly constrained due to inadequate quantification of the impact of supraglacial debris on glacier surface energy balance. Few data exist to describe spatial and temporal variations in parameters such as debris thickness, albedo and surface roughness in energy balance calculations. Consequently, improved understanding of how debris affects Himalayan glacier ablation requires the assessment of surface energy balance model sensitivity to spatial and temporal variability in these parameters. Measurements of debris thickness, surface temperature, reflectance and roughness were collected across Khumbu Glacier during the pre- and post-monsoon seasons of 2014 and 2015. The extent of the spatial variation in each of these parameters are currently being incorporated into a point-based glacier surface energy balance model (CMB-RES, Collier et al., 2014, The Cryosphere), applied on a pixel-by-pixel basis to the glacier surface, to ascertain the sensitivity of glacier surface energy balance and ablation values to these debris parameters. A time series of debris thickness maps have been produced for Khumbu Glacier over a 15-year period (2000-2015) using Mihalcea et al.'s (2008, Cold Reg. Sci. Technol.) method, which utilised multi-temporal ASTER thermal imagery and our in situ debris surface temperature and thickness measurements. Change detection between these maps allowed the identification of variations in debris thickness that could be compared to discrete measurements, glacier surface velocity and morphology of the debris-covered area. Debris thickness was found to vary spatially between 0.1 and 4 metres within each debris thickness map, and temporally on the order of 1

  18. Sediment transfer processes in a debris-flow dominated catchment in the Swiss Alps

    Science.gov (United States)

    McArdell, B. W.; Berger, C.; Schlunegger, F.

    2009-12-01

    debris flows probably originated from the sediments stored within the channels.

  19. Modeling debris-covered glaciers: extension due to steady debris input

    Directory of Open Access Journals (Sweden)

    L. S. Anderson

    2015-11-01

    Debris-forced glacier extension decreases the ratio of accumulation zone to total glacier area (AAR. The model reproduces first-order relationships between debris cover, AARs, and glacier surface velocities from glaciers in High Asia. We provide a quantitative, theoretical foundation to interpret the effect of debris cover on the moraine record, and to assess the effects of climate change on debris-covered glaciers.

  20. Mean Velocity Estimation of Viscous Debris Flows

    Institute of Scientific and Technical Information of China (English)

    Hongjuan Yang; Fangqiang Wei; Kaiheng Hu

    2014-01-01

    The mean velocity estimation of debris flows, especially viscous debris flows, is an impor-tant part in the debris flow dynamics research and in the design of control structures. In this study, theoretical equations for computing debris flow velocity with the one-phase flow assumption were re-viewed and used to analyze field data of viscous debris flows. Results show that the viscous debris flow is difficult to be classified as a Newtonian laminar flow, a Newtonian turbulent flow, a Bingham fluid, or a dilatant fluid in the strict sense. However, we can establish empirical formulas to compute its mean velocity following equations for Newtonian turbulent flows, because most viscous debris flows are tur-bulent. Factors that potentially influence debris flow velocity were chosen according to two-phase flow theories. Through correlation analysis and data fitting, two empirical formulas were proposed. In the first one, velocity is expressed as a function of clay content, flow depth and channel slope. In the second one, a coefficient representing the grain size nonuniformity is used instead of clay content. Both formu-las can give reasonable estimate of the mean velocity of the viscous debris flow.

  1. Space debris measurement program at Phillips Laboratory

    Science.gov (United States)

    Dao, Phan D.; Mcnutt, Ross T.

    1992-01-01

    Ground-based optical sensing was identified as a technique for measuring space debris complementary to radar in the critical debris size range of 1 to 10 cm. The Phillips Laboratory is building a staring optical sensor for space debris measurement and considering search and track optical measurement at additional sites. The staring sensor is implemented in collaboration with Wright Laboratory using the 2.5 m telescope at Wright Patterson AFB, Dayton, Ohio. The search and track sensor is designed to detect and track orbital debris in tasked orbits. A progress report and a discussion of sensor performance and search and track strategies will be given.

  2. Gradient Index in Wear Debris Image Collection

    Institute of Scientific and Technical Information of China (English)

    LVZhi-yong; GAOHui-liang; YANXin-ping

    2004-01-01

    In order to solve a problem of oil on-line monitoring, this instrument adopts a prinripium of self-focus lens of Gradieat index fiber( GRIN Len) to design optics system and magnetic circuit. For the magnetic circuit, the monitor can catch particle wear debris in oil. And for the optics circuit. GRIN Len can transfer image of debris to apparatus of gather image, e . g, CCD and camera. And the image of debris is transferred to computer for analyzing seize and physiognomy of debris. The character of the monitor is of micro weight, micro volume andcurve imaging And it is directly pluged into oil to catch image of wear particles.

  3. Gross β activity level of fallout in the environment around Qinshan Nuclear Power Plant

    Institute of Scientific and Technical Information of China (English)

    YE Ji-Da; CHEN Bin; WU Zong-Mei

    2005-01-01

    This paper presents the measurement results of gross β activities in fallout samples collected from the environment around Qinshan Nuclear Power Plant (NPP) during 1993-2002. The gross β activity of 191 samples collected at five monitoring spots were (0.11~3.64) Bq · m-2 · d-1, with an average of (0.91 ±0.49) Bq · m-2 · d-1. This value was lower than (1.02±0.35) Bq·m-2·d-1 , the average of the samples collected at the reference spot in Hangzhou.It indicated that no obvious rise in the gross β activity level of fallout was observed in ambience of Qinshan NPP.

  4. RESUME95 Nordic field test of mobile equipment for nuclear fall-out monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeois, C.; Bresson, J.; Chiffot, T.; Guillot, L. [Centre d`Etudes de Valduc, Direction des Applications Militaires, Commissaiat a L`Energie Atomique, Tille (France)

    1997-12-31

    Nordic Safety Research (NKS) organised in August 1995 a field test of various techniques and instrumentation for monitoring radioactive fall-out. In an emergency situation, after a major release of radioactive material, many different measuring systems are going to be used, ranging from small hand hold intensitometer to complex spectrometer systems. In this test the following type of equipment were tested: Airborne spectrometers; Carborne spectrometers and dose rate meters; In situ spectrometers and intensitometers. Helinuc team was equipped of an airborne system and of a germanium device for in situ measurements. Different tasks were specified for each team: Mapping caesium fall-out and natural activity over two areas of 18 and 5 km{sup 2}; Research of hidden sources. For measurements and data processing the respect of time allowed was strictly controlled for testing the ability of each team. (au).

  5. Airborne fallout mapping of {sup 137}Cs - STUK/HUT team

    Energy Technology Data Exchange (ETDEWEB)

    Nikkinen, M.; Aarnio, P. [Helsinki Univ. of Technology, Espoo (Finland); Honkamaa, T.; Tiilikainen, H. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

    1997-12-31

    The task of the team was to create a fallout map of {sup 137}Cs on a specified area in Padasjoki Auttoinen village. The team used AB-420 helicopter of the Finnish Frontier Guard. The team had two measuring systems: HPGe system (relative efficiency 18%) and NaI system (5`x5`). Both systems produced similar maps. The average {sup 137}Cs fallout within the area (lakes and ponds included) was 88 kBq m{sup -2,} the maximum value being 161 kBq m{sup -2}. In an emergency the HPGe is superior to NaI because of its better energy resolution, giving possibility to obtain nuclide-specific results. (au).

  6. Airborne fallout mapping of {sup 137}Cs Finnish defence forces team

    Energy Technology Data Exchange (ETDEWEB)

    Kettunen, M.; Heininen, T. [Finnish Defence Forces Research Centre, Lakiala (Finland); Pulakka, M. [Finnish Air Force Depot, Tampere (Finland)

    1997-12-31

    The main task of the team was to create a fallout map of {sup 137}Cs in a specified area in Padasjoki Auttoinen village. The team used an MI-8 helicopter of the Finnish Air Force. The team had an HPGe system (relative efficiency 70%) to measure nuclide specific ground contamination level. For navigation the team took advantage of the DGPS service provided by Finnish Broadcasting company utilizing the RDS-channel to get position accuracy within 2 meters. The correction signal is reachable nationwide on the FM transmitter network. The system produced a distribution map for {sup 40}K and fallout maps for {sup 134,137}Cs using a Micro Station Program with TerraModeler application. The maximum measured {sup 137}Cs ground contamination exceeded 130-140 kBqm{sup -2}. (au).

  7. (239)Pu fallout across continental Australia: Implications on (239)Pu use as a soil tracer.

    Science.gov (United States)

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

    2017-09-19

    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 atom ratios range from 0.045 to 0.197, with averages of 0.139(0.017), 0.111(0.052) and 0.160(0.027) in the 10-20°S, 20-30°S and 30-40°S latitude bands respectively. The (240)Pu/(239)Pu atom ratios in Central Australia (0.069) likely represent fallout from the Australian tests which also have low (240)Pu/(239)Pu atom ratios i.e., Maralinga (0.113) and Montebello (0.045). The average ratios in the 20-30°S and 30-40° bands are closer to the global average (0.139 and 0.177 respectively when not including the close-in fallout data from the nuclear test sites) if the Australian test sites and Central Australian sites are neglected as they clearly represent the effects of close in fallout. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Immunological effects of low dose radiation. Absent or minor effects of Chernobyl fallout in Norway?

    Energy Technology Data Exchange (ETDEWEB)

    Reitan, J.B.; Bergan, T.D.; Strand, P. [Statens Straalevern, Oesteraas (Norway); Melbye, O.J. [Rikshospitalet, Oslo (Norway)

    1998-01-01

    In this pilot study of those Norwegian individuals most heavily exposed to the Chernobyl Fallout, immunological parameters generally stayed within normal limits. However, some parameter, apparently within the assumed normal range did, in fact correlate to the estimated individual dose as assessed by wholebody counting of radiocaesium content. The small possible effects revealed in this study may represent real biological effects, but do not necessarily represent a health detriment. 43 refs., 4 figs., 6 tabs.

  9. Observations of fallout from the Fukushima reactor accident in San Francisco Bay area rainwater.

    Directory of Open Access Journals (Sweden)

    Eric B Norman

    Full Text Available We have observed fallout from the recent Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area. Gamma ray spectra measured from these samples show clear evidence of fission products--(131,132I, (132Te, and (134,137Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public.

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

    OpenAIRE

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

    2009-01-01

    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 accide...

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

    CERN Document Server

    Norman, Eric B; Chodash, Perry A

    2011-01-01

    We have observed fallout from the recent Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area. Gamma ray spectra measured from these samples show clear evidence of fission products - 131,132I, 132Te, and 134,137Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public.

  12. Geologic, geomorphic, and meteorological aspects of debris flows triggered by Hurricanes Frances and Ivan during September 2004 in the Southern Appalachian Mountains of Macon County, North Carolina (southeastern USA)

    Science.gov (United States)

    Wooten, R.M.; Gillon, K.A.; Witt, A.C.; Latham, R.S.; Douglas, T.J.; Bauer, J.B.; Fuemmeler, S.J.; Lee, L.G.

    2008-01-01

    In September 2004, rain from the remnants of Hurricanes Frances and Ivan triggered at least 155 landslides in the Blue Ridge Mountains of North Carolina. At least 33 debris flows occurred in Macon County, causing 5 deaths, destroying 16 homes, and damaging infrastructure. We mapped debris flows and debris deposits using a light-detecting and ranging digital elevation model, remote imagery and field studies integrated in a geographic information system. Evidence of past debris flows was found at all recent debris flow sites. Orographic rainfall enhancement along topographic escarpments influenced debris flow frequency at higher elevations. A possible trigger for the Wayah and fatal Peeks Creek debris flows was a spiral rain band within Ivan that moved across the area with short duration rainfall rates of 150-230 mm/h. Intersecting bedrock structures in polydeformed metamorphic rock influence the formation of catchments within structural-geomorphic domains where debris flows originate. ?? 2007 Springer-Verlag.

  13. Estimation of the Adriatic sea water turnover time using fallout 90Sr as a radioactive tracer

    CERN Document Server

    Franic, Z

    2004-01-01

    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/m3 in 1963 to 2.0 +/- 0.3 Bq/m3 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/m2 in 1963 to 0.4 Bq/m2 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 d...

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

    Science.gov (United States)

    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.

  15. Mapping of caesium fallout from the Chernobyl accident in the Jotunheimen area

    Energy Technology Data Exchange (ETDEWEB)

    Baranwal, Vikas C.; Ofstad, Frode; Roenning, Jan S.; Watson, Robin J.

    2011-07-01

    As a consequence of the Chernobyl accident, several areas in Norway received radioactive fallout. One of these areas is the eastern part of Jotunheimen in central Norway. Immediately after the accident in 1986, the Geological Survey of Norway (NGU) performed airborne gamma-ray spectroscopy in central Norway. At that time, it was not possible to calculate reliable radionuclide concentrations, and the data were presented as total counts per second. Several man-made radionuclides were present in the initial fallout, but due to short half-lives, most of these have now disintegrated into stable isotopes. 137Cs, with a half-life of 11.000 days ({approx} 30 years) is still present in the environment in significant quantities, leading to high radioactivity levels in meat from reindeer and sheep. To obtain a detailed map of the caesium fallout concentration in Jotunheimen, an airborne gamma-ray spectrometry (AGRS) survey was carried out, focussing on reindeer grazing areas. This project was a cooperation between Reindeer Husbandry Administration, Norwegian Radiation Protection Authority and the Geological Survey of Norway. (auth)

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

    Science.gov (United States)

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

    2008-12-01

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

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

    Science.gov (United States)

    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.

  18. Sedimentology, Behavior, and Hazards of Debris Flows at Mount Rainier, Washington

    Science.gov (United States)

    Scott, K.M.; Vallance, J.W.; Pringle, P.T.

    1995-01-01

    Mount Rainier is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle. Many debris flows and their distal phases have inundated areas far from the volcano during postglacial time. Two types of debris flows, cohesive and noncohesive, have radically different origins and behavior that relate empirically to clay content. The two types are the major subpopulations of debris flows at Mount Rainier. The behavior of cohesive flows is affected by the cohesion and adhesion of particles; noncohesive flows are dominated by particle collisions to the extent that particle cataclasis becomes common during near-boundary shear. Cohesive debris flows contain more than 3 to 5 percent of clay-size sediment. The composition of these flows changed little as they traveled more than 100 kilometers from Mount Rainier to inundate parts of the now-populated Puget Sound lowland. They originate as deep-seated failures of sectors of the volcanic edifice, and such failures are sufficiently frequent that they are the major destructional process of Mount Rainier's morphologic evolution. In several deposits of large cohesive flows, a lateral, megaclast-bearing facies (with a mounded or hummocky surface) contrasts with a more clay-rich facies in the center of valleys and downstream. Cohesive flows at Mount Rainier do not correlate strongly with volcanic activity and thus can recur without warning, possibly triggered by non-magmatic earthquakes or by changes in the hydrothermal system. Noncohesive debris flows contain less than 3 to 5 percent clay-size sediment. They form most commonly by bulking of sediment in water surges, but some originate directly or indirectly from shallow slope failures that do not penetrate the hydrothermally altered core of the volcano. In contrast with cohesive flows, most noncohesive flows transform both from and to other flow types and are, therefore, the

  19. Sampling supraglacial debris thickness using terrestrial photogrammetry

    Science.gov (United States)

    Nicholson, Lindsey; Mertes, Jordan

    2017-04-01

    The melt rate of debris-covered ice differs to that of clean ice primarily as a function of debris thickness. The spatial distribution of supraglacial debris thickness must therefore be known in order to understand how it is likely to impact glacier behaviour, and meltwater contribution to local hydrological resources and global sea level rise. However, practical means of determining debris cover thickness remain elusive. In this study we explore the utility of terrestrial photogrammetry to produce high resolution, scaled and texturized digital terrain models of debris cover exposures above ice cliffs as a means of quantifying and characterizing debris thickness. Two Nikon D5000 DSLRs with Tamron 100mm lenses were used to photograph a sample area of the Ngozumpa glacier in the Khumbu Himal of Nepal in April 2016. A Structure from Motion workflow using Agisoft Photoscan software was used to generate a surface models with debris thickness along the exposed cliffline were made from this scaled model, assuming that the ice surface at the debris-ice boundary is horizontal, and these data are compared to 50 manual point measurements along the same clifftops. We conclude that sufficiently high resolution photogrammetry, with precise scaling information, provides a useful means to determine debris thickness at clifftop exposures. The resolution of the possible measurements depends on image resolution, the accuracy of the ground control points and the computational capacity to generate centimetre scale surface models. Application of such techniques to sufficiently high resolution imagery from UAV-borne cameras may offer a powerful means of determining debris thickness distribution patterns over debris covered glacier termini.

  20. Assessment and prediction of debris-flow hazards

    Science.gov (United States)

    Wieczorek, Gerald F.; ,

    1993-01-01

    Study of debris-flow geomorphology and initiation mechanism has led to better understanding of debris-flow processes. This paper reviews how this understanding is used in current techniques for assessment and prediction of debris-flow hazards.

  1. Orbital Debris Observations with WFCAM

    Science.gov (United States)

    Bold, Matthew; Cross, Nick; Irwin, Mike; Kendrick, Richard; Kerr, Thomas; Lederer, Susan; Mann, Robert; Sutorius, Eckhard

    2014-01-01

    The United Kingdom Infrared Telescope has been operating for 35 years on the summit of Mauna Kea as a premier Infrared astronomical facility. In its 35th year the telescope has been turned over to a new operating group consisting of University of Arizona, University of Hawaii and the LM Advanced Technology Center. UKIRT will continue its astronomical mission with a portion of observing time dedicated to orbital debris and Near Earth Object detection and characterization. During the past 10 years the UKIRT Wide Field CAMera (WFCAM) has been performing large area astronomical surveys in the J, H and K bands. The data for these surveys have been reduced by the Cambridge Astronomical Survey Unit in Cambridge, England and archived by the Wide Field Astronomy Unit in Edinburgh, Scotland. During January and February of 2014 the Wide Field CAMera (WFCAM) was used to scan through the geostationary satellite belt detecting operational satellites as well as nearby debris. Accurate photometric and astrometric parameters have been developed by CASU for each of the detections and all data has been archived by WFAU.

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

    Science.gov (United States)

    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

  3. Radionuclide characterization and associated dose from long-lived radionuclides in close-in fallout delivered to the marine environment at Bikini and Enewetak Atoll

    Energy Technology Data Exchange (ETDEWEB)

    Noshkin, V. E.; Robison, W. L.

    1998-09-01

    Between June 1946 and October 1958, Enewetak and Bikini Atolls were used by the United States as testing grounds for 66 nuclear devices. The combined explosive yield from these tests was 107 Mt (Mt TNT equivalents). This testing produced close-in fallout debris that was contaminated with quantities of radioactive fission and particle activated products, and unspent radioactive nuclear fuel that entered the aquatic environment of the atolls. Today, the sediments in the lagoons are reservoirs for 10's of TBq of the transuranics and some long-lived fission and activation products. The larger amounts of contamination are associated with fine and coarse sediment material adjacent to the locations of the high yield explosions. Radionuclides are also distributed vertically in the sediment column to various depths in all regions of the lagoons. Concentrations greater than fallout background levels are found in filtered water sampled over several decades from all locations and depths in the lagoons. This is a direct indication that the radionuclides are continuously mobilized to solution from the solid phases. Of particular importance is the fact that the long-lived radionuclides are accumulated to different levels by indigenous aquatic plants and organisms that are used as food by resident people. One might anticipate finding continuous high contamination levels in many of the edible marine organisms from the lagoons, since the radionuclides associated with the sediments are not contained and are available to the different organisms in a relatively shallow water environment. This is not the case. We estimate that the radiological dose from consumption of the edible parts of marine foods at Enewetak and Bikini is presently about 0.05% of the total 50-year integral effective dose from all other exposure pathways that include ingestion of terrestrial foods and drinking water, external exposure and inhalation. The total radiological dose from the marine pathway is

  4. Radionuclide characterization and associated dose from long-lived radionuclides in close-in fallout delivered to the marine environment at Bikini and Enewetak Atoll

    Energy Technology Data Exchange (ETDEWEB)

    Noshkin, V. E.; Robison, W. L.

    1998-09-01

    Between June 1946 and October 1958, Enewetak and Bikini Atolls were used by the United States as testing grounds for 66 nuclear devices. The combined explosive yield from these tests was 107 Mt (Mt TNT equivalents). This testing produced close-in fallout debris that was contaminated with quantities of radioactive fission and particle activated products, and unspent radioactive nuclear fuel that entered the aquatic environment of the atolls. Today, the sediments in the lagoons are reservoirs for 10's of TBq of the transuranics and some long-lived fission and activation products. The larger amounts of contamination are associated with fine and coarse sediment material adjacent to the locations of the high yield explosions. Radionuclides are also distributed vertically in the sediment column to various depths in all regions of the lagoons. Concentrations greater than fallout background levels are found in filtered water sampled over several decades from all locations and depths in the lagoons. This is a direct indication that the radionuclides are continuously mobilized to solution from the solid phases. Of particular importance is the fact that the long-lived radionuclides are accumulated to different levels by indigenous aquatic plants and organisms that are used as food by resident people. One might anticipate finding continuous high contamination levels in many of the edible marine organisms from the lagoons, since the radionuclides associated with the sediments are not contained and are available to the different organisms in a relatively shallow water environment. This is not the case. We estimate that the radiological dose from consumption of the edible parts of marine foods at Enewetak and Bikini is presently about 0.05% of the total 50-year integral effective dose from all other exposure pathways that include ingestion of terrestrial foods and drinking water, external exposure and inhalation. The total radiological dose from the marine pathway is

  5. Himalayan glacier retreat delayed by debris cover

    Science.gov (United States)

    Scherler, D.; Bookhagen, B.; Strecker, M. R.

    2010-12-01

    Variable retreat rates and paucity of mass-balance data complicate a coherent picture of the current state and future fate of Himalayan glaciers. We report frontal changes and remotely-sensed surface velocities from >250 glaciers in the greater Himalayan realm (Hindu Kush, Karakoram, Himalaya, West Kunlun Shan) between 2000 and 2008 that provide evidence for widespread meltdown, which is obscured by debris cover. While debris-free glaciers in Tibet and other low-relief areas have been mainly retreating, debris-covered glaciers in high-relief areas, such as the central Himalaya, were mostly stagnating and in-situ down wasting but not retreating. Only Karakoram glaciers show no signs of stagnation or appreciable retreat, despite high debris cover, suggesting no recent mass loss. Our study shows that regional differences in topographic relief account for substantial differences in debris cover and thus retreat behaviour that need to be considered when comparing glacier retreat rates. The combination of melt rates lowered by debris cover and healthier glaciers in the strongly glaciated Karakoram slows down current glacier wastage in High Asia. Predictions of future water availability and global sea level have so far neglected the effect of debris cover on glacier melt rates and thus likely overestimate the speed of glacier meltdown in the Himalaya and other steep mountain ranges where debris covered glaciers are common.

  6. Estimates of current debris from flux models

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.

    1997-01-01

    Flux models that balance accuracy and simplicity are used to predict the growth of space debris to the present. Known and projected launch rates, decay models, and numerical integrations are used to predict distributions that closely resemble the current catalog-particularly in the regions containing most of the debris.

  7. CONCENTRATION AND VELOCITY OF DEBRIS FLOWS

    Institute of Scientific and Technical Information of China (English)

    Xiangjun FEI; Peng CUI; Yong LI

    2002-01-01

    Debris flows in nature generally fall into three groups distinct in their grain composition: water-stone flow,or sub-viscous debris flow,dominated by coarse grains; muddy flow,dominated by fine grains;and viscous debris flow composed of grains in large range. Liquid-phase velocity and sedimentary delivery resistance of sub-viscous debris flow have been discussed based on the composition characters of sub-and high-viscous debris flows. It is revealed that the presence of fine grains plays a vital role in affecting resistance and average velocity,particularly when the volume fraction of grains in the flow is relatively high,i.e. Sv > 0.45. Grain-size distribution of viscous debris flow is characterized by a bimodal curve,which explains the properties like high density and low resistance gradient of debris flows. A calculation formula is finally put forward,which has to some extent overcome locality limits and achieved a good agreement with the field observations of debris flows in Southwest China.

  8. Effects of radiation and debris to SSPS

    OpenAIRE

    Utashima, Masayoshi; 歌島 昌由

    2004-01-01

    This paper studies effects of the radiation and space debris to the Space Solar Power Systems (SSPS). In the first half of the paper, the in-space transportation from low-Earth orbit to geostationary Earth orbit is studied in consideration of these effects. In the second half, the debris impacts to SSPS on geostationary Earth orbit are analyzed.

  9. RETROSPECTIVE RECONSTRUCTION OF INTEGRAL IODINE-131 FALLOUT FOR THE SETTLEMENTS OF THE BRYANSK REGION OF RUSSIA ON THE BASIS OF RESULTS OF IODINE-129 CONTENT IN THE SOIL DETERMINATION IN 2008

    Directory of Open Access Journals (Sweden)

    Yu. I. Gavrilin

    2009-01-01

    Full Text Available The article briefly describes the procedure of reconstruction of integral iodine-131 fallouts using fragmentary data on iodine-131 fallouts in May-June 1986, as well as results of determination (in the late period after the accident of iodine-129 concentration in the soil and values of integral fallouts of cesium-137 in the settlements of the Bryansk region of Russia. Results of estimation of integral iodine-131 fallouts (in the area of 32 soil sampling points are presented in the table form. Regularities of ratio (131I/137CsII change in the integral radionuclide fallouts are being determined and values of integral iodine-131 fallouts are being estimatedfor the other settlements of the region with the known values of integral cesium-137 fallouts. It is shown that variability of the average for settlements values of integral iodine-131 fallouts is 70 times less then variability of corresponding integral cesium-137 fallouts.

  10. Development of the Space Debris Sensor (SDS)

    Science.gov (United States)

    Hamilton, J.; Liou, J.-C.; Anz-Meador, P. D.; Corsaro, B.; Giovane, F.; Matney, M.; Christiansen, E.

    2017-01-01

    The Space Debris Sensor (SDS) is a NASA experiment scheduled to fly aboard the International Space Station (ISS) starting in 2018. The SDS is the first flight demonstration of the Debris Resistive/Acoustic Grid Orbital NASA-Navy Sensor (DRAGONS) developed and matured at NASA Johnson Space Center's Orbital Debris Program Office. The DRAGONS concept combines several technologies to characterize the size, speed, direction, and density of small impacting objects. With a minimum two-year operational lifetime, SDS is anticipated to collect statistically significant information on orbital debris ranging from 50 microns to 500 microns in size. This paper describes the features of SDS and how data from the ISS mission may be used to update debris environment models. Results of hypervelocity impact testing during the development of SDS and the potential for improvement on future sensors at higher altitudes will be reviewed.

  11. Planets, debris and their host metallicity correlations

    CERN Document Server

    Fletcher, Mark

    2016-01-01

    Recent observations of debris discs, believed to be made up of remnant planetesimals, brought a number of surprises. Debris disc presence does not correlate with the host star's metallicity, and may anti-correlate with the presence of gas giant planets. These observations contradict both assumptions and predictions of the highly successful Core Accretion model of planet formation. Here we explore predictions of the alternative Tidal Downsizing (TD) scenario of planet formation. In TD, small planets and planetesimal debris is made only when gas fragments, predecessors of giant planets, are tidally disrupted. We show that these disruptions are rare in discs around high metallicity stars but release more debris per disruption than their low [M/H] analogs. This predicts no simple relation between debris disc presence and host star's [M/H], as observed. A detected gas giant planet implies in TD that its predecessor fragment was not disputed, potentially explaining why DDs are less likely to be found around stars w...

  12. Debris flows: behavior and hazard assessment

    Science.gov (United States)

    Iverson, Richard M.

    2014-01-01

    Debris flows are water-laden masses of soil and fragmented rock that rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form lobate deposits when they spill onto valley floors. Because they have volumetric sediment concentrations that exceed 40 percent, maximum speeds that surpass 10 m/s, and sizes that can range up to ~109 m3, debris flows can denude slopes, bury floodplains, and devastate people and property. Computational models can accurately represent the physics of debris-flow initiation, motion and deposition by simulating evolution of flow mass and momentum while accounting for interactions of debris' solid and fluid constituents. The use of physically based models for hazard forecasting can be limited by imprecise knowledge of initial and boundary conditions and material properties, however. Therefore, empirical methods continue to play an important role in debris-flow hazard assessment.

  13. Development of the Space Debris Sensor (SDS)

    Science.gov (United States)

    Hamilton, Joe; Liou, J. -C.; Anz-Meador, P.; Matney, M.; Christiansen, E.

    2017-01-01

    Debris Resistive/Acoustic Grid Orbital Navy-NASA Sensor (DRAGONS) is an impact sensor designed to detect and characterize collisions with small orbital debris: from 50 microns to greater than 1millimeter debris size detection; Characterizes debris size, speed, direction, and density. The Space Debris Sensor (SDS) is a flight demonstration of DRAGONS on the International Space Station: Approximately 1 square meter of detection area facing the ISS velocity vector; Minimum two year mission on Columbus External Payloads Facility (EPF); Minimal obstruction from ISS hardware; Development is nearing final checkout and integration with the ISS; Current launch schedule is SpaceX13, about September 2017, or SpaceX14, about Jan 2018.

  14. The debris-flow rheology myth

    Science.gov (United States)

    Iverson, R.M.; ,

    2003-01-01

    Models that employ a fixed rheology cannot yield accurate interpretations or predictions of debris-flow motion, because the evolving behavior of debris flows is too complex to be represented by any rheological equation that uniquely relates stress and strain rate. Field observations and experimental data indicate that debris behavior can vary from nearly rigid to highly fluid as a consequence of temporal and spatial variations in pore-fluid pressure and mixture agitation. Moreover, behavior can vary if debris composition changes as a result of grain-size segregation and gain or loss of solid and fluid constituents in transit. An alternative to fixed-rheology models is provided by a Coulomb mixture theory model, which can represent variable interactions of solid and fluid constituents in heterogeneous debris-flow surges with high-friction, coarse-grained heads and low-friction, liquefied tails. ?? 2003 Millpress.

  15. Debris disc formation induced by planetary growth

    CERN Document Server

    Kobayashi, Hiroshi

    2014-01-01

    Several hundred stars older than 10 million years have been observed to have infrared excesses. These observations are explained by dust grains formed by the collisional fragmentation of hidden planetesimals. Such dusty planetesimal discs are known as debris discs. In a dynamically cold planetesimal disc, collisional coagulation of planetesimals produces planetary embryos which then stir the surrounding leftover planetesimals. Thus, the collisional fragmentation of planetesimals that results from planet formation forms a debris disc. We aim to determine the properties of the underlying planetesimals in debris discs by numerically modelling the coagulation and fragmentation of planetesimal populations. The brightness and temporal evolution of debris discs depend on the radial distribution of planetesimal discs, the location of their inner and outer edges, their total mass, and the size of planetesimals in the disc. We find that a radially narrow planetesimal disc is most likely to result in a debris disc that ...

  16. Comparison of space-debris and asteroid photometric properties

    Science.gov (United States)

    Murtazov, A.

    2014-07-01

    Optical detection and identification of space debris originating from different sources is a vital objective nowadays. The most commonly used, effective, and accessible are photometric observations of natural and artificial space objects for determining their color and albedo. The color index and albedo data eventually provide information allowing to identify the observed surface. The author's investigations have shown that the surface optical properties of man-made objects are quite diverse [4-6]. Part of the artificial debris surfaces have both diffuse and specular components. Their color characteristics are quite different from those of the natural surfaces. Diffuse scattering of light from artificial surfaces is quite orthotropic and can, at a first approximation, be defined by the Lambert law. Quite a significant role here can be played by glory effects in glass fibers, which additionally decrease the phase curve slopes. The phase coefficient of these surfaces varies from 0.010 to 0.013 magnitude/degree. The colors of natural atmosphereless celestial bodies are practically all reddish and brown- grey. Therefore, the position of natural atmosphereless body surface materials in the «albedo-color index» diagram is close to the position of reddish artificial coverings with the low albedo. This does not make it possible to discriminate between them by using color indices. The surfaces of natural debris have rather low albedos and color indices corresponding to grey-brown and reddish bodies. Light scattering by natural atmosphereless astronomical body surfaces is far from being ideal. It is influenced by mutual shadowing of surface particles, the tubular structure of regolith covering the surfaces, etc. Their scattering is diffuse and differs from that of the Lambert law and is described by the Hapke and Lommel-Seeliger functions regarding the porosity of such surfaces [1, 2]. Thus, the phase coefficients of atmosphereless astronomical body phase curves and

  17. Airborne measurements of fission product fall-out

    Energy Technology Data Exchange (ETDEWEB)

    Hovgaard, J.; Korsbech, U.

    1992-12-01

    During 1993 the Danish Emergency Management Agency will install an airborne [gamma]-ray detector system for area survey of contamination with radioactive nuclides - primarily fission products that may be released during a heavy accident at a nuclear power plant or from accidents during transport of radioactive material. The equipment is based on 16 liter NaI(TI) crystals and multichannel analysers from Exploranium (Canada). A preliminary investigation of the possibilities for detection of low and high level contamination - and the problems that may be expected during use of the equipment, and during interpretation of the measured data, is described. Several days after reactor shut-down some of the nuclides can be identified directly from the measured spectrum, and contamination levels may be determined within a factor two. After several weeks, most fission products have decayed. Concentrations and exposure rates can be determined with increasing accuracy as time passes. Approximate calibration of the equipment for measurements of surface contamination and natural radioactivity can be performed in the laboratory. Further checks of equipment should include accurate measurements of the spectrum resolution. Detectors should be checked individually, and all together. Further control of dead time and pulse pile-up should be performed. Energy calibration, electronics performance and data equipment should be tested against results from the original calibration. (AB).

  18. Developing Insights into Debris Disk Composition from Dust Scattering

    Science.gov (United States)

    Weinberger, Alycia

    relevant to debris disk dust. In particular, we expect grains to be mixtures of silicates with ice and carbonaceous inclusions and to have porosities that reflect either cometary-like (high volatile content) or asteroidal-like (compacted) structures. Methodology: We propose to make discrete dipole (DDA) calculations of the interaction of light with debris-disk-like particles. DDA does a better job modeling high porosity than other approximations such as effective medium theory and provides the efficiencies of both scattering and absorption. We will calculate grain scattering efficiencies, albedos, phase functions, and polarizations for wavelengths out to a few microns for grains in which we vary total size and composition. Into a range of grain shapes and sizes, we will incorporate silicates (amorphous and crystalline), carbonaceous components (organics and amorphous), ices, and porosities. To expand the library of carbonaceous components, we will measure UV to near-infrared absorption spectra of laboratory-generated analogs to primitive solar system organic solids. We will compare the resulting grid of calculations to the colors of disks to determine how precisely dust composition may be estimated with spatially resolved photometry and spectroscopy. Relevance: Debris disks are the relics of formation and evolution of planetary systems, and they connect our solar system's small body population with that of exosolar systems. The can "improve our understanding of the origins of exoplanetary systems". We are currently using HST and ground-based adaptive optics systems to image disks from 0.4 - 4 microns. We will compare our new scattering calculations to existing data, and future missions that will add new disk color images, such as JWST and a WFIRST-AFTA coronagraph, provide a further impetus to make such calculations.

  19. Processing the ground vibration signal produced by debris flows: the methods of amplitude and impulses compared

    Science.gov (United States)

    Arattano, M.; Abancó, C.; Coviello, V.; Hürlimann, M.

    2014-12-01

    Ground vibration sensors have been increasingly used and tested, during the last few years, as devices to monitor debris flows and they have also been proposed as one of the more reliable devices for the design of debris flow warning systems. The need to process the output of ground vibration sensors, to diminish the amount of data to be recorded, is usually due to the reduced storing capabilities and the limited power supply, normally provided by solar panels, available in the high mountain environment. There are different methods that can be found in literature to process the ground vibration signal produced by debris flows. In this paper we will discuss the two most commonly employed: the method of impulses and the method of amplitude. These two methods of data processing are analyzed describing their origin and their use, presenting examples of applications and their main advantages and shortcomings. The two methods are then applied to process the ground vibration raw data produced by a debris flow occurred in the Rebaixader Torrent (Spanish Pyrenees) in 2012. The results of this work will provide means for decision to researchers and technicians who find themselves facing the task of designing a debris flow monitoring installation or a debris flow warning equipment based on the use of ground vibration detectors.

  20. A Primer on Unifying Debris Disk Morphologies

    CERN Document Server

    Lee, Eve J

    2016-01-01

    A "minimum model" for debris disks consists of a narrow ring of parent bodies, secularly forced by a single planet on a possibly eccentric orbit, colliding to produce dust grains that are perturbed by stellar radiation pressure. We demonstrate how this minimum model can reproduce a wide variety of disk morphologies imaged in scattered starlight. Five broad categories of disk shape can be captured: "rings," "needles," "ships-and-wakes," "bars," and "moths (a.k.a. fans)," depending on the viewing geometry. Moths can also sport "double wings." We explain the origin of morphological features from first principles, exploring the dependence on planet eccentricity, disk inclination dispersion, and the parent body orbital phases at which dust grains are born. A key determinant in disk appearance is the degree to which dust grain orbits are apsidally aligned. Our study of a simple steady-state (secularly relaxed) disk should serve as a reference for more detailed models tailored to individual systems. We use the intui...

  1. Observations of Titan 3C-4 Transtage Fragmentation Debris

    Science.gov (United States)

    Cowardin, Heather; Seitzer, P.; Abercromby, K.; Barker, E.; Cardona, T.; Krisko, P.; Lederer, S.

    2013-01-01

    The fragmentation of a Titan 3C-4 Transtage (1968-081) on 21 February 1992 is one of only two known break-ups in or near geosynchronous orbit. The original rocket body and 24 pieces of debris are currently being tracked by the US Space Surveillance Network (SSN). The rocket body (SSN# 3432) and several of the original fragments (SSN# 25000, 25001, 30000, and 33511) were observed in survey mode during 2004-2010 using the 0.6-m Michigan Orbital DEbris Survey Telescope (MODEST) in Chile using a broad R filter. This paper will present a size distribution for all calibrated magnitude data acquired on MODEST. Size distribution plots will also be shown using historical models for small fragmentation debris (down to 10 cm) believed to be associated with the Titan break-up. In November 2010, visible broadband photometry (Johnson/Kron-Cousins BVRI) was acquired with the 0.9-m Small and Moderate Aperture Research Telescope System (SMARTS) at the Cerro Tololo Inter-American Observatory (CTIO) in Chile on several Titan fragments (SSN# 25001, 33509, 33510) and the parent rocket body. Color index data will be used to determine the fragment brightness distribution and how the data compares to spacecraft materials measured in the laboratory using similar photometric measurement techniques. In 2012, the SSN added 16 additional fragments to the catalogue. MODEST acquired magnitude data on ten Titan fragments in late 2012 and early 2013. The magnitude distribution of all the observed fragments are analyzed as a function of time. In order to better characterize the breakup fragments spectral measurements were acquired on the original rocket body and five Titan fragments using the 6.5-m Magellan telescopes at Las Campanas Observatory in Chile. The telescopic spectra are compared with laboratory acquired spectra of materials (e.g., Aluminum and various paints) and categorized based on known absorption features for spacecraft materials.

  2. Erosion of steepland valleys by debris flows

    Science.gov (United States)

    Stock, J.D.; Dietrich, W.E.

    2006-01-01

    Episodic debris flows scour the rock beds of many steepland valleys. Along recent debris-flow runout paths in the western United States, we have observed evidence for bedrock lowering, primarily by the impact of large particles entrained in debris flows. This evidence may persist to the point at which debris-flow deposition occurs, commonly at slopes of less than ???0.03-0.10. We find that debris-flow-scoured valleys have a topographic signature that is fundamentally different from that predicted by bedrock river-incision models. Much of this difference results from the fact that local valley slope shows a tendency to decrease abruptly downstream of tributaries that contribute throughgoing debris flows. The degree of weathering of valley floor bedrock may also decrease abruptly downstream of such junctions. On the basis of these observations, we hypothesize that valley slope is adjusted to the long-term frequency of debris flows, and that valleys scoured by debris flows should not be modeled using conventional bedrock river-incision laws. We use field observations to justify one possible debris-flow incision model, whose lowering rate is proportional to the integral of solid inertial normal stresses from particle impacts along the flow and the number of upvalley debris-flow sources. The model predicts that increases in incision rate caused by increases in flow event frequency and length (as flows gain material) downvalley are balanced by rate reductions from reduced inertial normal stress at lower slopes, and stronger, less weathered bedrock. These adjustments lead to a spatially uniform lowering rate. Although the proposed expression leads to equilibrium long-profiles with the correct topographic signature, the crudeness with which the debris-flow dynamics are parameterized reveals that we are far from a validated debris-flow incision law. However, the vast extent of steepland valley networks above slopes of ???0.03-0.10 illustrates the need to understand debris

  3. Wear Debris Analysis:Fundamental Principle of Wear-Graphy

    Institute of Scientific and Technical Information of China (English)

    陈铭; 王伟华; 殷勇辉; 王成焘

    2004-01-01

    A new wear-graphy technology was developed, which can simultaneously identify the shape and composition of wear debris, for both metals and non-metals.The fundamental principles of the wear-graphy system and its wear-gram system are discussed here.A method was developed to distribute wear debris on a slide uniformly to reduce overlapping of wear debris while smearing.The composition identification analyzes the wear debris using the scanning electron microscope (SEM) energy spectrum, infrared-thermal imaging and X-ray imaging technology.A wear debris analysis system based on database techniques is demonstrated, and a visible digitized wear-gram is acquired based on the information of wear debris with image collection and processing of the wear debris.The method gives the morphological characteristics of the wear debris, material composition identification of the wear debris, intelligent recognition of the wear debris, and storage and management of wear debris information.

  4. The Debris of Urban Imagination

    Directory of Open Access Journals (Sweden)

    Claudio Sgarbi

    2013-05-01

    Full Text Available “Il Guasto” is an urban context, a place in the heart of the historic city of Bologna which is a mound of debris (resulting from the demolition of an important building, the Bentivoglio Family palace during a popular revolt in the 1506 on top of which a “public garden” was created 40 years ago. The garden is well known in Bologna as “Giardino del Guasto”. Underneath, in between the debris, an underground space (bunker was created to protect the citizen during the bombing of the second world war.The aim of the Design Studio of Azrieli School of Architecture and Urbanism, Carleton University (Ottawa, Canada, DSA Directed Studies Abroad (January 15th - April 13th, 2012, is to exercise creativity and design skills in an historical context bearing some negative connotations. A spell was cast on the site and the negative effects of this spell are still perceivable today after more than five hundred years. This makes us ponder upon the notions of permanence and durability (of architecture and ideas in the urban fabric and in the meanders of human memory. The site, centered on a garden, has been undergoing many changes in use, purpose and meaning and today still requires to be reimagined in the social context of the city and its famous university. [In the menu on the right, ARTICLE TOOLS, in "Supplementary Files" link you can download the .pdf presentations of Carleton University students, related to the workshop on Giardino del Guasto area, developed in Bologna in 2012].

  5. Erosive Hit-and-Run Impact Events: Debris Unbound

    CERN Document Server

    Sarid, Gal; Leinhardt, Zoe M

    2015-01-01

    Erosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup of these collisionally produced bodies is different from the canonical chondritic composition, in terms of rock/iron ratio and may contain further shock-processed material. Having some of the material in the asteroid belt owe its origin from collisions of larger planetary bodies may help in explaining some of the diversity and oddities in composition of different asteroid groups.

  6. The Costa Rican Central Valley Lavina Formation: Lahar or Debris Avalanche?

    Science.gov (United States)

    Hidalgo, P. J.; Alvarado Induni, G. E.; Linkimer, L.

    2005-12-01

    The Lavina Formation of the Central Valley of Costa Rica consists of lava blocks floating in a volcanic mud matrix. Different authors have interpreted this deposit genetically as a lahar or debris flow deposit. Based on geomorphologic, textural, and morphometric evidence, we conclude that the origin of this deposit is a debris avalanche event that transformed into a debris flow on its path down the valley. Using aerial photographs, many debris avalanche amphitheaters are found in the western sector of the Irazu volcanic complex. However, textural and morphometric characteristics of the deposit are consistent with the source of the sector collapse being located on the west flank of the Cabeza de Vaca volcano. Three-dimensional modeling of the Lavina Formation was done using data from 213 drill cores distributed along the Central Valley area. Maps of isopaches and isohipses of the roof and floor of this stratum were created. These allowed for qualification of morphometry of the stratigraphic surfaces, characterization of the paleoslopes, and quantification of the compacted deposit volume. The data derived form the isopach and isohipse contour maps indicate that abrupt changes in the thickness of the stratum are common. Also, it illustrates the morphological differences between the roof, elongated hills in the direction of the flux, and the floor of the stratum, smooth and uniform. The morphometric, geomorphologic, and textural evidence, were used to conclude that the Lavina deposit originated as a debris avalanche event in the Cabeza de Vaca Volcano. The debris avalanche was eventually fluidized into a debris flow that spread extensively (130 km2) along the Central Valley of Costa Rica.

  7. United theory of biological evolution:Disaster-forced evolution through Supernova, radioactive ash fall-outs, genome instability, and mass extinctions

    Institute of Scientific and Technical Information of China (English)

    Toshikazu Ebisuzaki; Shigenori Maruyama

    2015-01-01

    scale) also has been undergoing in cichlid fishes and great African apes in the last several tens of thousand years in the current African rift valley, including the origin of humankind due to the radioactive ash fall-outs by continental alkaline volcanism.

  8. United theory of biological evolution: Disaster-forced evolution through Supernova, radioactive ash fall-outs, genome instability, and mass extinctions

    Directory of Open Access Journals (Sweden)

    Toshikazu Ebisuzaki

    2015-01-01

    similar rapid speciation (though in a much smaller scale also has been undergoing in cichlid fishes and great African apes in the last several tens of thousand years in the current African rift valley, including the origin of humankind due to the radioactive ash fall-outs by continental alkaline volcanism.

  9. Space Debris Removal: A Game Theoretic Analysis

    Directory of Open Access Journals (Sweden)

    Richard Klima

    2016-08-01

    Full Text Available We analyse active space debris removal efforts from a strategic, game-theoretical perspective. Space debris is non-manoeuvrable, human-made objects orbiting Earth, which pose a significant threat to operational spacecraft. Active debris removal missions have been considered and investigated by different space agencies with the goal to protect valuable assets present in strategic orbital environments. An active debris removal mission is costly, but has a positive effect for all satellites in the same orbital band. This leads to a dilemma: each agency is faced with the choice between the individually costly action of debris removal, which has a positive impact on all players; or wait and hope that others jump in and do the ‘dirty’ work. The risk of the latter action is that, if everyone waits, the joint outcome will be catastrophic, leading to what in game theory is referred to as the ‘tragedy of the commons’. We introduce and thoroughly analyse this dilemma using empirical game theory and a space debris simulator. We consider two- and three-player settings, investigate the strategic properties and equilibria of the game and find that the cost/benefit ratio of debris removal strongly affects the game dynamics.

  10. Wildfire-related debris-flow initiation processes, Storm King Mountain, Colorado

    Science.gov (United States)

    Cannon, S.H.; Kirkham, R.M.; Parise, M.

    2001-01-01

    A torrential rainstorm on September 1, 1994 at the recently burned hillslopes of Storm King Mountain, CO, resulted in the generation of debris flows from every burned drainage basin. Maps (1:5000 scale) of bedrock and surficial materials and of the debris-flow paths, coupled with a 10-m Digital Elevation Model (DEM) of topography, are used to evaluate the processes that generated fire-related debris flows in this setting. These evaluations form the basis for a descriptive model for fire-related debris-flow initiation. The prominent paths left by the debris flows originated in 0- and 1st-order hollows or channels. Discrete soil-slip scars do not occur at the heads of these paths. Although 58 soil-slip scars were mapped on hillslopes in the burned basins, material derived from these soil slips accounted for only about 7% of the total volume of material deposited at canyon mouths. This fact, combined with observations of significant erosion of hillslope materials, suggests that a runoff-dominated process of progressive sediment entrainment by surface runoff, rather than infiltration-triggered failure of discrete soil slips, was the primary mechanism of debris-flow initiation. A paucity of channel incision, along with observations of extensive hillslope erosion, indicates that a significant proportion of material in the debris flows was derived from the hillslopes, with a smaller contribution from the channels. Because of the importance of runoff-dominated rather than infiltration-dominated processes in the generation of these fire-related debris flows, the runoff-contributing area that extends upslope from the point of debris-flow initiation to the drainage divide, and its gradient, becomes a critical constraint in debris-flow initiation. Slope-area thresholds for fire-related debris-flow initiation from Storm King Mountain are defined by functions of the form Acr(tan ??)3 = S, where Acr is the critical area extending upslope from the initiation location to the

  11. Transient dust in warm debris disks - Detection of Fe-rich olivine grains

    CERN Document Server

    Olofsson, Johan; Henning, Thomas; Mutschke, Harald; Tamanai, Akemi; Moor, Attila; Abraham, Peter

    2012-01-01

    (Abridged) Debris disks trace remnant reservoirs of leftover planetesimals in planetary systems. A handful of "warm" debris disks have been discovered in the last years, where emission in excess starts in the mid-infrared. An interesting subset within these warm debris disks are those where emission features are detected in mid-IR spectra, which points towards the presence of warm micron-sized dust grains. Given the ages of the host stars, the presence of these grains is puzzling, and questions their origin and survival in time. This study focuses on determining the mineralogy of the dust around 7 debris disks with evidence for warm dust, based on Spitzer/IRS spectroscopic data, in order to provide new insights into the origin of the dust grains. We present a new radiative transfer code dedicated to SED modeling of optically thin disks. We make use of this code on the SEDs of seven warm debris disks, in combination with recent laboratory experiments on dust optical properties. We find that most, if not all, d...

  12. POST Earthquake Debris Management - AN Overview

    Science.gov (United States)

    Sarkar, Raju

    Every year natural disasters, such as fires, floods, earthquakes, hurricanes, landslides, tsunami, and tornadoes, challenge various communities of the world. Earthquakes strike with varying degrees of severity and pose both short- and long-term challenges to public service providers. Earthquakes generate shock waves and displace the ground along fault lines. These seismic forces can bring down buildings and bridges in a localized area and damage buildings and other structures in a far wider area. Secondary damage from fires, explosions, and localized flooding from broken water pipes can increase the amount of debris. Earthquake debris includes building materials, personal property, and sediment from landslides. The management of this debris, as well as the waste generated during the reconstruction works, can place significant challenges on the national and local capacities. Debris removal is a major component of every post earthquake recovery operation. Much of the debris generated from earthquake is not hazardous. Soil, building material, and green waste, such as trees and shrubs, make up most of the volume of earthquake debris. These wastes not only create significant health problems and a very unpleasant living environment if not disposed of safely and appropriately, but also can subsequently impose economical burdens on the reconstruction phase. In practice, most of the debris may be either disposed of at landfill sites, reused as materials for construction or recycled into useful commodities Therefore, the debris clearance operation should focus on the geotechnical engineering approach as an important post earthquake issue to control the quality of the incoming flow of potential soil materials. In this paper, the importance of an emergency management perspective in this geotechnical approach that takes into account the different criteria related to the operation execution is proposed by highlighting the key issues concerning the handling of the construction

  13. Algorithms for the Computation of Debris Risks

    Science.gov (United States)

    Matney, Mark

    2017-01-01

    Determining the risks from space debris involve a number of statistical calculations. These calculations inevitably involve assumptions about geometry - including the physical geometry of orbits and the geometry of non-spherical satellites. A number of tools have been developed in NASA's Orbital Debris Program Office to handle these calculations; many of which have never been published before. These include algorithms that are used in NASA's Orbital Debris Engineering Model ORDEM 3.0, as well as other tools useful for computing orbital collision rates and ground casualty risks. This paper will present an introduction to these algorithms and the assumptions upon which they are based.

  14. Algorithms for the Computation of Debris Risk

    Science.gov (United States)

    Matney, Mark J.

    2017-01-01

    Determining the risks from space debris involve a number of statistical calculations. These calculations inevitably involve assumptions about geometry - including the physical geometry of orbits and the geometry of satellites. A number of tools have been developed in NASA’s Orbital Debris Program Office to handle these calculations; many of which have never been published before. These include algorithms that are used in NASA’s Orbital Debris Engineering Model ORDEM 3.0, as well as other tools useful for computing orbital collision rates and ground casualty risks. This paper presents an introduction to these algorithms and the assumptions upon which they are based.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    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.

  17. Appendix to health and safety laboratory environmental quarterly. [Tabulated data on fallout radioactivity in environment

    Energy Technology Data Exchange (ETDEWEB)

    1977-04-01

    Data are tabulated on: the content of /sup 90/Sr and /sup 89/Sr in monthly deposition at monitoring sites in the USA and other locations throughout the world; the content of /sup 90/Sr in milk samples collected in New York City; the content of /sup 137/Cs and /sup 90/Sr in samples of drinking water collected in New York City; and the content of fallout radionuclides and lead in samples of surface air collected at various world sites during 1976. (CH)

  18. Toxoplasma antibodies and retinochoroiditis in the Marshall Islands and their association with exposure to radioactive fallout

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Use of fallout radionuclides ((7)Be, (210)Pb) to estimate resuspension of Escherichia coli from streambed sediments during floods in a tropical montane catchment.

    Science.gov (United States)

    Ribolzi, Olivier; Evrard, Olivier; Huon, Sylvain; Rochelle-Newall, Emma; Henri-des-Tureaux, Thierry; Silvera, Norbert; Thammahacksac, Chanthamousone; Sengtaheuanghoung, Oloth

    2016-02-01

    Consumption of water polluted by faecal contaminants is responsible for 2 million deaths annually, most of which occur in developing countries without adequate sanitation. In tropical aquatic systems, streambeds can be reservoirs of persistent pathogenic bacteria and high rainfall can lead to contaminated soils entering streams and to the resuspension of sediment-bound microbes in the streambed. Here, we present a novel method using fallout radionuclides ((7)Be and (210)Pbxs) to estimate the proportions of Escherichia coli, an indicator of faecal contamination, associated with recently eroded soil particles and with the resuspension of streambed sediments. We show that using these radionuclides and hydrograph separations we are able to characterize the proportion of particles originating from highly contaminated soils and that from the resuspension of particle-attached bacteria within the streambed. We also found that although overland flow represented just over one tenth of the total flood volume, it was responsible for more than two thirds of the downstream transfer of E. coli. We propose that data obtained using this method can be used to understand the dynamics of faecal indicator bacteria (FIB) in streams thereby providing information for adapted management plans that reduce the health risks to local populations. Graphical Abstract Graphical abstract showing (1) the main water flow processes (i.e. overland flow, groundwater return flow, blue arrows) and sediment flow components (i.e. resuspension and soil erosion, black arrows) during floods in the Houay Pano catchment; (2) the general principle of the method using fallout radionuclide markers (i.e. (7)Be and (210)Pbxs) to estimate E. coli load from the two main sources (i.e. streambed resuspension vs soil surface washoff); and 3) the main results obtained during the 15 May 2012 storm event (i.e. relative percentage contribution of each process to the total streamflow, values in parentheses).

  20. RemoveDebris – Mission Analysis for a Low Cost Active Debris Removal Demonstration in 2016

    OpenAIRE

    Joffre, E; Forshaw, J.; Secretin, T; Reynaud, S.; Salmon, T; Aurelien, P; Aglietti, G.

    2015-01-01

    Contracted by the European Commission in the frame of the EU’s Seventh Framework Programme for Research (FP7), a wide European consortium has been working since 2013 towards the design of a low cost in-orbit demonstration called RemoveDEBRIS. With a targeted launch date in the second quarter of 2016, the RemoveDEBRIS mission aims at demonstrating key Active Debris Removal (ADR) technologies, including capture means (net and harpoon firing on a distant target), relative navigation techniques (...

  1. Search for the Data of Space Debris Initial Distribution

    Science.gov (United States)

    Ping-Ping, Zhang; Bao-Jun, Pang

    Space debris environment model is one of the kernels of the research on space debris Space debris environment model is based on the data of space debris that is if we have the data of space debris orbit parameter we can determine the state of space debris distribution and then the spacecraft risk assessment can be executed Because numbers of small size space debris cannot be detected or observed we have not small size space debris data The short of small size space debris data leads to the engineering model inaccurate model needs to be updated while in the status of seriously short of data the model can not be updated in time In allusion to the problem of scarcity of data on the basis of modern computer arithmetic this paper is trying to search new data with old data and the results of the model is close to other engineering models Key words space debris data

  2. An Assessment of the Current LEO Debris Environment and the Need for Active Debris Removal

    Science.gov (United States)

    Liou, Jer-Chyi

    2010-01-01

    The anti-satellite test on the Fengun-1 C weather satellite in early 2007 and the collision between Iridium 33 and Cosmos 2251 in 2009 dramatically altered the landscape of the human-made orbital debris environment in the low Earth orbit (LEO). The two events generated approximately 5500 fragments large enough to be tracked by the U.S. Space Surveillance Network. Those fragments account for more than 60% increase to the debris population in LEO. However, even before the ASAT test, model analyses already indicated that the debris population (for those larger than 10 cm) in LEO had reached a point where the population would continue to increase, due to collisions among existing objects, even without any future launches. The conclusion implies that as satellites continue to be launched and unexpected breakup events continue to occur, commonly-adopted mitigation measures will not be able to stop the collision-driven population growth. To remediate the debris environment in LEO, active debris removal must be considered. This presentation will provide an updated assessment of the debris environment after the Iridium 33/Cosmos 2251 collision, an analysis of several future environment projections based on different scenarios, and a projection of collision activities in LEO in the near future. The need to use active debris removal to stabilize future debris environment will be demonstrated and the effectiveness of various active debris removal strategies will be quantified.

  3. Comparison of an Inductance In-Line Oil Debris Sensor and Magnetic Plug Oil Debris Sensor

    Science.gov (United States)

    Dempsey, Paula J.; Tuck, Roger; Showalter, Stephen

    2012-01-01

    The objective of this research was to compare the performance of an inductance in-line oil debris sensor and magnetic plug oil debris sensor when detecting transmission component health in the same system under the same operating conditions. Both sensors were installed in series in the NASA Glenn Spiral Bevel Gear Fatigue Rig during tests performed on 5 gear sets (pinion/gear) when different levels of damage occurred on the gear teeth. Results of this analysis found both the inductance in-line oil debris sensor and magnetic plug oil debris sensor have benefits and limitations when detecting gearbox component damage.

  4. Orbital Debris Shape Characterization Project Abstract

    Science.gov (United States)

    Pease, Jessie

    2016-01-01

    I have been working on a project to further our understanding of orbital debris by helping create a new dataset previously too complex to be implemented in past orbital debris propagation models. I am doing this by creating documentation and 3D examples and illustrations of the shape categories. Earlier models assumed all orbital debris to be spherical aluminum fragments. My project will help expand our knowledge of shape populations to 6 categories: Straight Needle/Rod/Cylinder, Bent Needle/Rod/Cylinder, Flat Plate, Bent Plate, Nugget/Parallelepiped/Spheroid, and Flexible. The last category, Flexible, is still up for discussion and may be modified. These categories will be used to characterize fragments in the DebriSat experiment.

  5. New solutions for the space debris problem

    CERN Document Server

    Pelton, Joseph N

    2015-01-01

    Addressing a pressing issue in space policy, Pelton explores the new forms of technology that are being developed to actively remove the defunct space objects from orbit and analyzes their implications in the existing regime of international space law and public international law. This authoritative review covers the due diligence guidelines that nations are using to minimize the generation of new debris, mandates to de-orbit satellites at end of life, and innovative endeavours to remove non-functional satellites, upper stage rockets and other large debris from orbit under new institutional, financial and regulatory guidelines.  Commercial space services currently exceed 100 billion USD business per annum, but the alarming proliferation in the population of orbital debris in low, medium and geosynchronous satellite orbits poses a serious threat to all kinds of space assets and applications. There is a graver concern that the existing space debris will begin to collide in a cascading manner, generating furth...

  6. CLUSTERING ANALYSIS OF DEBRIS-FLOW STREAMS

    Institute of Scientific and Technical Information of China (English)

    Yuan-Fan TSAI; Huai-Kuang TSAI; Cheng-Yan KAO

    2004-01-01

    The Chi-Chi earthquake in 1999 caused disastrous landslides, which triggered numerous debris flows and killed hundreds of people. A critical rainfall intensity line for each debris-flow stream is studied to prevent such a disaster. However, setting rainfall lines from incomplete data is difficult, so this study considered eight critical factors to group streams, such that streams within a cluster have similar rainfall lines. A genetic algorithm is applied to group 377 debris-flow streams selected from the center of an area affected by the Chi-Chi earthquake. These streams are grouped into seven clusters with different characteristics. The results reveal that the proposed method effectively groups debris-flow streams.

  7. Wear debris in cemented total hip arthroplasty.

    Science.gov (United States)

    Huo, M H; Salvati, E A; Buly, R L

    1991-03-01

    One of the most prevalent clinical problems in long-term follow up of total hip arthroplasty patients is loosening of prosthetic fixation. Factors contributing to mechanical failure of total hip reconstruction are complex and multiple. It has become increasingly apparent that wear debris from the prosthetic components may contribute significantly to this process. The authors summarize some of the current concepts concerning the detrimental effects of metallic debris in total hip arthroplasty.

  8. Expanding capabilities of the debris analysis workstation

    Science.gov (United States)

    Spencer, David B.; Sorge, Marlon E.; Mains, Deanna L.; Shubert, Ann J.; Gerhart, Charlotte M.; Yates, Ken W.; Leake, Michael

    1996-10-01

    Determining the hazards from debris-generating events is a design and safety consideration for a number of space systems, both currently operating and planned. To meet these and other requirements, the United States Air Force (USAF) Phillips Laboratory (PL) Space Debris Research Program has developed a simulation software package called the Debris Analysis Workstation (DAW). This software provides an analysis capability for assessing a wide variety of debris hazards. DAW integrates several component debris analysis models and data visualization tools into a single analysis platform that meets the needs for Department of Defense space debris analysis, and is both user friendly and modular. This allows for studies to be performed expeditiously by analysts who are not debris experts. The current version of DAW includes models for spacecraft breakup, debris orbital lifetime, collision hazard risk assessment, and collision dispersion, as well as a satellite catalog database manager, a drag inclusive propagator, a graphical user interface, and data visualization routines. Together they provide capabilities to conduct several types of analyses, ranging from range safety assessments to satellite constellation risk assessment. Work is progressing to add new capabilities with the incorporation of additional models and improved designs. The existing tools are in their initial integrated form, but the 'glue' that will ultimately bring them together into an integrated system is an object oriented language layer scheduled to be added soon. Other candidate component models under consideration for incorporation include additional orbital propagators, error estimation routines, other dispersion models, and other breakup models. At present, DAW resides on a SUNR workstation, although future versions could be tailored for other platforms, depending on the need.

  9. DebriSat Pre Preshot Laboratory Analyses

    Science.gov (United States)

    2015-03-27

    to be line of sight since witness plates protected by Whipple shield showed little change. LWIR spectral features from the deposited material are...Radhakrishnan Charles Griffice C. C. Wan UV -VIS-NIR Spectroscopy Dianna Alaan FIB/TEM Sample Preparation Miles Brodie © The Aerospace Corporation 2015 DebriSat...conditions responsible for the darkening. – UV -VIS-NIR-LWIR reflectance spectra were measured of post test debris for comparison with pre test

  10. Pore Water Pressure Contribution to Debris Flow Mobility

    OpenAIRE

    Chiara Deangeli

    2009-01-01

    Problem statement: Debris flows are very to extremely rapid flows of saturated granular soils. Two main types of debris flow are generally recognized: Open slope debris flows and channelized debris flows. The former is the results of some form of slope failures, the latter can develop along preexisting stream courses by the mobilization of previously deposited debris blanket. The problem to be addressed is the influence of the mode of initiation on the subsequent mechanism of propagation. In ...

  11. Designing Shelter in New Buildings. A Manual for Architects on the Preliminary Designing of Shielding from Fallout Gamma Radiation in Normally Functioning Spaces in New Buildings.

    Science.gov (United States)

    Knott, Albert

    Analysis of radiation fallout prevention factors in new construction is presented with emphasis on architectural shielding principles. Numerous diagrams and charts illustrate--(1) radiation and fallout properties, (2) building protection principles, (3) details and planning suggestions, and (4) tabular data interpretation. A series of charts is…

  12. Direct Detection of Dark Matter Debris Flows

    CERN Document Server

    Kuhlen, Michael; Spergel, David N

    2012-01-01

    Tidal stripping of dark matter from subhalos falling into the Milky Way produces narrow, cold tidal streams as well as more spatially extended "debris flows" in the form of shells, sheets, and plumes. Here we focus on the debris flow in the Via Lactea II simulation, and show that this incompletely phase-mixed material exhibits distinctive high-velocity behavior. Unlike tidal streams, which may not necessarily intersect the Earth's location, debris flow is spatially uniform at 8 kpc and thus guaranteed to be present in the dark matter flux incident on direct detection experiments. At Earth-frame velocities greater than 450 km/s, debris flow comprises more than half of the dark matter at the Sun's location, and up to 80% at even higher velocities. Therefore, debris flow is most important for experiments that are particularly sensitive to the high velocity tail of the dark matter distribution, such as searches for light or inelastic dark matter or experiments with directional sensitivity. We show that debris flo...

  13. Chaotic Dispersal of Tidal Debris

    CERN Document Server

    Price-Whelan, Adrian M; Valluri, Monica; Pearson, Sarah; Kupper, Andreas H W; Hogg, David W

    2015-01-01

    Several long, dynamically cold stellar streams have been observed around the Milky Way Galaxy, presumably formed from the tidal disruption of globular clusters. In integrable potentials---where all orbits are dynamically regular---tidal debris phase-mixes close to the orbit of the progenitor system. However, cosmological simulations of structure formation suggest that the Milky Way's dark matter halo is expected not to be fully integrable; an appreciable fraction of orbits will be chaotic. This paper examines the influence of chaos on the phase-space morphology of cold tidal streams. We find very stark results: Streams in chaotic regions look very different from those in regular regions. We find that streams (simulated using test particle ensembles of nearby orbits) can be sensitive to chaos on a much shorter time-scale than any standard prediction (from the Lyapunov or frequency-diffusion times). For example, on a weakly chaotic orbit with a chaotic timescale predicted to be >1000 orbital periods (>1000 Gyr)...

  14. Analysis of Debris Flows Characteristics of the Guojiamo Gully%郭家磨沟泥石流的特征研究

    Institute of Scientific and Technical Information of China (English)

    吴义鹰

    2012-01-01

    泥石流发生的成因及其影响因素较多,通过对泥石流沟的特征和成因分析,可为泥石流的防治和对工程的影响评价提供依据。%The debris flow occurs the origin and its the influence factor are more.through to the debris flow characteristic and the origin analysis,it may provide the basis for debris flow preventing and controlling and the influence appraisal to the project.

  15. Catastrophic debris avalanche deposit of Socompa volcano, northern Chile

    Science.gov (United States)

    Francis, P. W.; Gardeweg, M.; Ramirez, C. F.; Rothery, D. A.

    1985-01-01

    Between 10,000 and 500 yr ago the Socompa volcano in northern Chile experienced a catastrophic collapse of a 70 deg sector of the original cone, causing a debris avalanche that descended nearly 3000 m vertically and traveled more than 35 km from the volcano. The deposits cover some 490 sq km and have a minimum volume of 15 cu km. Parts of the original cone slumped in a nearly coherent form and are now preserved as large blocks more than 400 m high. The primary avalanche traveled northwestward over sloping ground before coming to rest transiently, forming a prominent marginal ridge, and then slid away northeastward to form a secondary flow, overriding much of the primary avalanche deposit. Abundant, prismatic, jointed dacite blocks within the debris avalanche deposit and a thin, fine-grained pumiceous deposit beneath it suggest that the collapse was triggered by magmatic activity and may have been accompanied by a violent lateral blast. Collapse was followed by eruption of pumiceous pyroclastic flows and extrusion of voluminous dacite domes.

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

    Science.gov (United States)

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

    2014-10-01

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

  17. ESR dosimetry study for the residents of Kazakhstan exposed to radioactive fallout on 24, August 1956

    Energy Technology Data Exchange (ETDEWEB)

    Zhumadilov, K., E-mail: kassym@hiroshima-u.ac.jp [Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Ivannikov, A. [Medical Radiological Research Center, Obninsk 249036 (Russian Federation); Zharlyganova, D. [Astana Medical University, 51a, Beibitshilik str., Astana 010000 (Kazakhstan); Zhumadilov, Zh. [Nazarbayev University, Life Sciences Center, D. Kunayev str., Astana 010000 (Kazakhstan); Stepanenko, V. [Medical Radiological Research Center, Obninsk 249036 (Russian Federation); Abralina, Sh.; Sadvokasova, L. [Semey State Medical Academy, Semey 071400, Abay str. 103 (Kazakhstan); Zhumadilova, A. [Astana Medical University, 51a, Beibitshilik str., Astana 010000 (Kazakhstan); Toyoda, S. [Department of Applied Physics, Faculty of Science, Okayama University of Science, Okayama 700-0005 (Japan); Endo, S. [Department of Quantum Energy Applications, Graduated School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527 (Japan); Okamoto, T. [Department of Molecular Oral Medicine and Maxillofacial Surgery, Division of Frontier Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553 (Japan); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan)

    2011-09-15

    The method of electron spin resonance (ESR) dosimetry has been applied to human tooth enamel in order to obtain individual absorbed doses from the population of settlements within the vicinity of the central axis of the radioactive fallout trace from the contaminating nuclear surface test of 24, August 1956. Most of the settlements (Glubokoe, Tavriya, and Gagarino) are located near Ust-Kamenogorsk city, in Kazakhstan (about 400 km to the east from the epicenter of the explosion at the Semipalatinsk Nuclear Test Site (SNTS)). It was found that the excess doses obtained after the subtraction of natural background radiation ranged up to about 120 mGy for the residents of Ust-Kamenogorsk city, whose tooth enamel was formed before 1956. For the residents of Gagarino, excess doses do not exceed 47 mGy for all ages. For the residents of Tavriya, the maximum of excess dose was determined as 54 mGy and for the residents of Glubokoe, the maximum excess dose was about 83 mGy. For the population of the Shemonaikha settlements (about 70 km from the centerline of the radioactive fallout trace) the highest excess dose is 110 mGy. Also for this study, Znamenka village (about 130 km from the epicenter) was included. The Kokpekty settlement was chosen as a control and not subjected to any radioactive contamination and is located 400 km to the Southeast from SNTS.

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

    DEFF Research Database (Denmark)

    Palsson, S.E.; Howard, B.J.; Bergan, T.D.

    2013-01-01

    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 corre......, allowing comparison with time series of activity concentrations for different environmental compartments, which is important for model validation. © 2012 Elsevier Ltd. All rights reserved.......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...... 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...

  19. Global analysis of anthropogenic debris ingestion by sea turtles.

    Science.gov (United States)

    Schuyler, Qamar; Hardesty, Britta Denise; Wilcox, Chris; Townsend, Kathy

    2014-02-01

    Ingestion of marine debris can have lethal and sublethal effects on sea turtles and other wildlife. Although researchers have reported on ingestion of anthropogenic debris by marine turtles and implied incidences of debris ingestion have increased over time, there has not been a global synthesis of the phenomenon since 1985. Thus, we analyzed 37 studies published from 1985 to 2012 that report on data collected from before 1900 through 2011. Specifically, we investigated whether ingestion prevalence has changed over time, what types of debris are most commonly ingested, the geographic distribution of debris ingestion by marine turtles relative to global debris distribution, and which species and life-history stages are most likely to ingest debris. The probability of green (Chelonia mydas) and leatherback turtles (Dermochelys coriacea) ingesting debris increased significantly over time, and plastic was the most commonly ingested debris. Turtles in nearly all regions studied ingest debris, but the probability of ingestion was not related to modeled debris densities. Furthermore, smaller, oceanic-stage turtles were more likely to ingest debris than coastal foragers, whereas carnivorous species were less likely to ingest debris than herbivores or gelatinovores. Our results indicate oceanic leatherback turtles and green turtles are at the greatest risk of both lethal and sublethal effects from ingested marine debris. To reduce this risk, anthropogenic debris must be managed at a global level. © 2013 The Authors. Conservation Biology published by Wiley Periodicals, Inc., on behalf of the Society for Conservation Biology.

  20. Triggering conditions and depositional characteristics of a disastrous debris flow event in Zhouqu city, Gansu Province, northwestern China

    Directory of Open Access Journals (Sweden)

    C. Tang

    2011-11-01

    Full Text Available On 7 August 2010, catastrophic debris flows were triggered by a rainstorm in the catchments of the Sanyanyu and Luojiayu torrents, Zhouqu County, Gansu Province northwestern China. These two debris flows originated shortly after a rainstorm with an intensity of 77.3 mm h−1 and transported a total volume of about 2.2 million m3, which was deposited on an existing debris fan and into a river. This catastrophic event killed 1765 people living on this densely urbanised fan. The poorly sorted sediment contains boulders up to 3–4 m in diameter. In this study, the geomorphological features of both debris flow catchment areas are analyzed based on the interpretation of high-resolution remote sensing imagery combined with field investigation. The characteristics of the triggering rainfall and the initiation of the debris flow occurrence are discussed. Using empirical equations, the peak velocities and discharges of the debris flows were estimated to be around 9.7 m s−1 and 1358 m3 s−1 for the Sanyanyu torrent and 11 m s−1 and 572 m3 s−1 for the Luojiayu torrent. The results of this study contribute to a better understanding of the conditions leading to catastrophic debris flow events.

  1. The International Space Station and the Space Debris Environment: 10 Years On

    Science.gov (United States)

    Johnson, Nicholas; Klinkrad, Heiner

    2009-01-01

    For just over a decade the International Space Station (ISS), the most heavily protected vehicle in Earth orbit, has weathered the space debris environment well. Numerous hypervelocity impact features on the surface of ISS caused by small orbital debris and meteoroids have been observed. In addition to typical impacts seen on the large solar arrays, craters have been discovered on windows, hand rails, thermal blankets, radiators, and even a visiting logistics module. None of these impacts have resulted in any degradation of the operation or mission of the ISS. Validating the rate of small particle impacts on the ISS as predicted by space debris environment models is extremely complex. First, the ISS has been an evolving structure, from its original 20 metric tons to nearly 300 metric tons (excluding logistics vehicles) ten years later. Hence, the anticipated space debris impact rate has grown with the increasing size of ISS. Secondly, a comprehensive visual or photographic examination of the complete exterior of ISS has never been accomplished. In fact, most impact features have been discovered serendipitously. Further complications include the estimation of the size of an impacting particle without knowing its mass, velocity, and angle of impact and the effect of shadowing by some ISS components. Inadvertently and deliberately, the ISS has also been the source of space debris. The U.S. Space Surveillance Network officially cataloged 65 debris from ISS from November 1998 to November 2008: from lost cameras, sockets, and tool bags to intentionally discarded equipment and an old space suit. Fortunately, the majority of these objects fall back to Earth quickly with an average orbital lifetime of less than two months and a maximum orbital lifetime of a little more than 15 months. The cumulative total number of debris object-years is almost exactly 10, the equivalent of one piece of debris remaining in orbit for 10 years. An unknown number of debris too small to be

  2. A process for fire-related debris flow initiation, Cerro Grande fire, New Mexico

    Science.gov (United States)

    Cannon, S.H.; Bigio, E.R.; Mine, E.

    2001-01-01

    In this study we examine factors that pertain to the generation of debris flows from a basin recently burned by wildfire. Throughout the summer 2000 thunderstorm season, we monitored rain gauges, channel cross-sections, hillslope transects, and nine sediment-runoff traps deployed in a steep, 0??15 km2 basin burned by the May 2000 Cerro Grande fire in New Mexico. Debris flows were triggered in the monitored basin during a rainstorm on July 16, 2000, in response to a maximum 30 min rainfall intensity of 31 mm h-1 (return period of approximately 2 years). Eleven other storms occurred before and after the July storm; these storms resulted in significant runoff, but did not generate debris flows. The debris flows generated by the July 16 storm initiated on a broad, open hillslope as levee-lined rills. The levees were composed of gravel- and cobble-sized material supported by an abundant fine-grained matrix. Debris-flow deposits were observed only on the hillslopes and in the first and second-order drainages of the monitored basin. No significant amounts of channel incision were measured following the passage of the debris flows, indicating that most of the material in the flows originated from the hillslopes. Sediment-runoff concentrations of between 0??23 and 0??81 kg 1-1 (with a mean of 0-42 kg 1-1) were measured from the hillslope traps following the debris-flow-producing storm. These concentrations, however, were not unique to the July 16 storm. The materials entrained by the July 16 storm contained a higher proportion of silt- plus clay-sized materials in the debris flows. The difference in materials demonstrates the critical role of the availability of fine-grained wood ash mantling the hillslopes in the runoff-dominated generation of post-wildfire debris flows. The highest sediment-runoff concentrations, again not unique to debris-flow production, were produced from maximum 30 min rainfall intensities greater than 20 mm h-1. Copyright ?? 2001 John Wiley and Sons

  3. Jarvis Fallout.

    Science.gov (United States)

    McCuen, John T.; Hoffland, Ginger

    1978-01-01

    With the passage of Proposition 13, California's community colleges lost an estimated two-thirds of their local revenues. As the largest such system, the Los Angeles Community College District is preparing for the hardest impact. Retrenchment, loss of local control, and legal difficulties are problems it faces. (JMD)

  4. Mapping of debris-covered glaciers in parts of the Greater Himalaya Range, Ladakh, western Himalaya, using remote sensing and GIS

    Science.gov (United States)

    Ghosh, Swagata; Pandey, Arvind C.; Nathawat, Mahendra S.

    2014-01-01

    Glacier inventories based on visual interpretation and manual delineation of glacier boundaries are time consuming. Supraglacial debris (debris accumulated on glacier terrain) of Himalayan glaciers creates difficulty with automated glacier mapping when using satellite images. In the present study, a combination of band ratio using the TM image and slope parameter was proven to be useful for delineating glaciers' debris-covered areas. Compared to original TM bands, supervised classification using a combination of principal components two, three, and six of debris and nonglacierized areas facilitated identification of various types of supraglacial debris. Use of principal components four, three, and two of snow- and ice-covered areas as input bands for supervised classification was helpful in classifying different types of snow and ice. Results corresponded well with manually delineated glacier outlines and field observations. Error matrix revealed that the accuracy of classification of the snow- and ice-covered parts of glaciers was 86.29%. Although manual editing was required to differentiate supraglacial debris from periglacial debris (debris outside the glacier boundary), the approach using the ability of morphometric parameter combined with band ratio for delineation of debris-covered parts of glaciers and supervised classification with principal component analysis for mapping of supraglacial covers is observed to be faster than manual delineation.

  5. A globally complete map of supraglacial debris cover and a new toolkit for debris cover research

    Science.gov (United States)

    Herreid, Sam; Pellicciotti, Francesca

    2017-04-01

    A growing canon of literature is focused on resolving the processes and implications of debris cover on glaciers. However, this work is often confined to a handful of glaciers that were likely selected based on criteria optimizing their suitability to test a specific hypothesis or logistical ease. The role of debris cover in a glacier system is likely to not go overlooked in forthcoming research, yet the magnitude of this role at a global scale has not yet been fully described. Here, we present a map of debris cover for all glacierized regions on Earth including the Greenland Ice Sheet using 30 m Landsat data. This dataset will begin to open a wider context to the high quality, localized findings from the debris-covered glacier research community and help inform large-scale modeling efforts. A global map of debris cover also facilitates analysis attempting to isolate first order geomorphological and climate controls of supraglacial debris production. Furthering the objective of expanding the inclusion of debris cover in forthcoming research, we also present an under development suite of open-source, Python based tools. Requiring minimal and often freely available input data, we have automated the mapping of: i) debris cover, ii) ice cliffs, iii) debris cover evolution over the Landsat era and iv) glacier flow instabilities from altered debris structures. At the present time, debris extent is the only globally complete quantity but with the expanding repository of high quality global datasets and further tool development minimizing manual tasks and computational cost, we foresee all of these tools being applied globally in the near future.

  6. Radar-based observatiions of variable thickness debris cover on martian ice masses: evidence of debris transfer by flowing ice on Mars

    Science.gov (United States)

    Souness, Colin; Brough, Stephen; Woodward, John; Hubbard, Bryn; Davis, Joel; Grindrod, Peter

    2016-04-01

    The mid-latitudes of Mars host a wide range of ice-based landforms, many of which display surface morphologies indicative of viscous flow of that ice. Despite being shrouded beneath a layer of rocky debris, these viscous flow features (VFFs) are thought to have similarities with terrestrial glaciers. Until recently most studies that focussed on the origin, structure and role of these martian VFFs were restricted to observations made from satellite imagery. Little data have been available to gain a clearer picture of VFF internal structure, which has impeded our collective ability to infer many particulars of VFF growth and flow, including the extent to which these ice flows have interacted with, and potentially helped shape, the martian landscape. However, the Shallow Radar (SHARAD) system mounted on the Mars Reconnaissance Orbiter (MRO) can, in some cases, provide a valuable insight into what lies beneath the surface of these ice masses. We present a SHARAD-based study of glacial systems on Mars which reveals pronounced heterogeneity in the thickness of their observed superficial debris covers. The surface debris layers in question appear to thicken in a down-slope direction. Radar data indicates that in the lower reaches of each studied glacial catchment, ice surface debris cover exceeds 10 m in thickness. The observed flow-parallel a-symmetry in debris thickness atop these martian glaciers is similar to that recorded on many terrestrial glaciers, indicating that cumulative down-flow debris mass transfer such as occurs within glacierised catchments on Earth may also currently operate, or have operated, on Mars. This suggests that glaciers on Mars have played a substantial role in redistributing lithic material from mountainous catchments to lower-lying areas, potentially throughout the glacial regions of Mars' mid-latitudes, thus making an important processual contribution to the evolution of Mars' contemporary landscape.

  7. Carbon Stocks of Fine Woody Debris in Coppice Oak Forests at Different Development Stages

    Directory of Open Access Journals (Sweden)

    Ender Makineci

    2017-06-01

    Full Text Available Dead woody debris is a significant component of the carbon cycle in forest ecosystems. This study was conducted in coppice-originated oak forests to determine carbon stocks of dead woody debris in addition to carbon stocks of different ecosystem compartments from the same area and forests which were formerly elucidated. Weight and carbon stocks of woody debris were determined with recent samplings and compared among development stages (diameter at breast height (DBH, D1.3m, namely small-diameter forests (SDF = 0–8 cm, medium diameter forests (MDF = 8–20 cm, and large-diameter forests (LDF = 20–36 cm. Total woody debris was collected in samplings; as bilateral diameters of all woody debris parts were less than 10 cm, all woody parts were in the “fine woody debris (FWD” class. The carbon concentrations of FWD were about 48% for all stages. Mass (0.78–4.92 Mg·ha−1 and carbon stocks (0.38–2.39 Mg·ha−1 of FWD were significantly (p > 0.05 different among development stages. FWD carbon stocks were observed to have significant correlation with D1.3m, age, basal area, and carbon stocks of aboveground biomass (Spearman rank correlation coefficients; 0.757, 0.735, 0.709, and 0.694, respectively. The most important effects on carbon budgets of fine woody debris were determined to be coppice management and intensive utilization. Also, national forestry management, treatments of traditional former coppice, and conversion to high forest were emphasized as having substantial effects.

  8. Widespread detection of a brominated flame retardant, hexabromocyclododecane, in expanded polystyrene marine debris and microplastics from South Korea and the Asia-Pacific coastal region.

    Science.gov (United States)

    Jang, Mi; Shim, Won Joon; Han, Gi Myung; Rani, Manviri; Song, Young Kyoung; Hong, Sang Hee

    2017-08-30

    The role of marine plastic debris and microplastics as a carrier of hazardous chemicals in the marine environment is an emerging issue. This study investigated expanded polystyrene (EPS, commonly known as styrofoam) debris, which is a common marine debris item worldwide, and its additive chemical, hexabromocyclododecane (HBCD). To obtain a better understanding of chemical dispersion via EPS pollution in the marine environment, intensive monitoring of HBCD levels in EPS debris and microplastics was conducted in South Korea, where EPS is the predominant marine debris originate mainly from fishing and aquaculture buoys. At the same time, EPS debris were collected from 12 other countries in the Asia-Pacific region, and HBCD concentrations were measured. HBCD was detected extensively in EPS buoy debris and EPS microplastics stranded along the Korean coasts, which might be related to the detection of a quantity of HBCD in non-flame-retardant EPS bead (raw material). The wide detection of the flame retardant in sea-floating buoys, and the recycling of high-HBCD-containing EPS waste inside large buoys highlight the need for proper guidelines for the production and use of EPS raw materials, and the recycling of EPS waste. HBCD was also abundantly detected in EPS debris collected from the Asia-Pacific coastal region, indicating that HBCD contamination via EPS debris is a common environmental issue worldwide. Suspected tsunami debris from Alaskan beaches indicated that EPS debris has the potential for long-range transport in the ocean, accompanying the movement of hazardous chemicals. The results of this study indicate that EPS debris can be a source of HBCD in marine environments and marine food web. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Patterns of marine debris distribution on the beaches of Rottnest Island, Western Australia.

    Science.gov (United States)

    Smith, Stephen D A; Gillies, Chris L; Shortland-Jones, Helen

    2014-11-15

    Rottnest Island, Western Australia, receives >500,000 visitors y(-1), who are mainly attracted by the Island's natural values. Marine debris is a threat to both these natural values and to Island wildlife, and is consequently an important issue for managers. Engaging with volunteers, we quantified marine debris at 16 beach sites around the Island. The highest loads occurred on the SW coast and primarily comprised items originating from fishing activities. Sites on the NE coast, where >95% of the Island's accommodation is located, supported the highest abundance of items deposited in situ (e.g. bottles and cigarette butts). We conclude that marine debris management may require a range of strategies to address the different primary sources. Raising awareness through education and intervention may be highly effective at popular beaches on the NE coast, but broader liaison with commercial and recreational fishers will be necessary to address the issue at the Island scale.

  10. The influence of dust grain porosity on the analysis of debris disc observations

    CERN Document Server

    Brunngräber, Robert; Kirchschlager, Florian; Ertel, Steve

    2016-01-01

    Debris discs are often modelled assuming compact dust grains, but more and more evidence for the presence of porous grains is found. We aim at quantifying the systematic errors introduced when modelling debris discs composed of porous dust with a disc model assuming spherical, compact grains. We calculate the optical dust properties derived via the fast, but simple effective medium theory. The theoretical lower boundary of the size distribution -- the so-called 'blowout size' -- is compared in the cases of compact and porous grains. Finally, we simulate observations of hypothetical debris discs with different porosities and feed them into a fitting procedure using only compact grains. The deviations of the results for compact grains from the original model based on porous grains are analysed. We find that the blowout size increases with increasing grain porosity up to a factor of two. An analytical approximation function for the blowout size as a function of porosity and stellar luminosity is derived. The ana...

  11. Interpreting the extended emission around three nearby debris disc host stars

    CERN Document Server

    Marshall, Jonathan P; Ertel, S; Augereau, J -C; Kennedy, G M; Booth, M; Wolf, S; Montesinos, B; Eiroa, C; Matthews, B

    2014-01-01

    Cool debris discs are a relic of the planetesimal formation process around their host star, analogous to the solar system's Edgeworth-Kuiper belt. As such, they can be used as a proxy to probe the origin and formation of planetary systems like our own. The Herschel Open Time Key Programmes "DUst around NEarby Stars" (DUNES) and "Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre" (DEBRIS) observed many nearby, sun-like stars at far-infrared wavelengths seeking to detect and characterize the emission from their circumstellar dust. Excess emission attributable to the presence of dust was identified from around $\\sim$ 20% of stars. Herschel's high angular resolution ($\\sim$ 7" FWHM at 100 $\\mu$m) provided the capacity for resolving debris belts around nearby stars with radial extents comparable to the solar system (50 to 100 au). As part of the DUNES and DEBRIS surveys, we obtained observations of three debris disc stars, HIP 22263 (HD 30495), HIP 62207 (HD 110897), and HIP 72848 (HD 1315...

  12. Water fact sheet, history of landslides and debris flows at Mount Rainier

    Science.gov (United States)

    Scott, K.M.; Vallance, J.W.

    1993-01-01

    Many landslides and debris flows have originated from Mount Rainier since the retreat of glaciers from Puget Sound about 10,000 years ago. The recurrent instability is due to several factors--height of the steep-sided volcanic cone, frequent volcanic activity, continuous weakening of rock by steam and hot, chemical-laden water, and exposure of unstable areas as the mountains glaciers have receded. The landslide scars and deposits tell a fascinating story of the changing shape of the volcano. Landslides occur when part of the volcano "collapses" or fails and slides away from the rest of the volcano. The failed mass rapidly breaks up into a jumble of disaggregated pieces that flow at high velocity like a fluid. Clay and water in the debris cause further change to a liquid slurry known as a debris flow or mudflow. Volcanic debris flows are also widely known by the Indonesian term "lahar." Although the largest debris flows at Rainier form from landslides, many smaller flows are caused by volcanic eruptions, intense rainfall, and glacial-outburst floods.

  13. LATE PLIOCENE-HOLOCENE DEBRIS FLOW DEPOSITS IN THE IONIAN SEA (EASTERN MEDITERRANEAN

    Directory of Open Access Journals (Sweden)

    GIOVANNI ALOISI DE LARDEREL

    1997-11-01

    Full Text Available Widespread coring of the Eastern Mediterranean Basin has outlined the existence of a systematic relation between lithology of debris flow deposits and physiographic setting. Whilst the topographic highs are characterized by pelagic sedimentation, the basin floors are alternatively subject to pelagic sedimentation and re-sedimentation pro cesses. Amongst the latters, turbidity flows and debris flows are the most common transport mechanisms.In this paper we present the study of the debris flow pro cess in the Ionian Sea using visual description of cores, grain size, carbonate content and smear slide analysis carried out on gravity and piston cores recovered over the past 20 years. A distinction has been made between debris flow deposits originating from the continental margins (North Africa and Malta Escarpment and those emplaced in the small basins amidst the Calabrian and Mediterranean ridges "Cobblestone Topography". As a result of the difference in setting, the former debris flow deposits include a great variety of lithologies and ages whilst the latter involve the pelagic sediments forming the typical Eastern Mediterranean Plio-Quaternary succession. A detailed study of clast and matrix structures makes it possible to describe the flows in terms of existing classifications of sediment gravity flows and to assume a clast support mechanism. Finally, biostratigraphy coupled with the presence of widespread marker beds enabled us to estimate the age of emplacement of the deposits and to hypothesize a triggering mechanism for flow initiation. Three flows are strictly related to the pelagic turbidite named homogenite, triggered by the explosive eruption of the Santorini volcano (Minoan eruption and therefore have an estimated age of 3,500 BP. The other deposits have ages ranging from 9,000 BP to about 70,000 BP and were originated by debris flows triggered by events such as earthquakes and glacial low sea level stands.    

  14. Overview of the space debris environment

    Science.gov (United States)

    Meshishnek, M. J.

    1995-03-01

    There is a component of the space environment that is man-made pollution, termed 'space debris' it exists at all inclinations and, primarily, at altitudes of roughly 350 km to 2000 km. The size of this debris ranges from several meters to a fraction of a micrometer in diameter, and the particle distribution follows an inverse power law, with the smaller size component far exceeding that of the larger. Debris is composed primarily of alumina from solid rocket motor exhausts, aluminum from spacecraft structures, and zinc and titanium oxides from thermal control coatings. The accepted model of the space debris environment is that of Kessler et al., a complex model that predicts the number of particles that will impact a surface as a function of altitude, inclination, solar cycle, and particle diameter, as well as their collision velocities. Recent data from LDEF has demonstrated both the accuracy and shortcomings of the Kessler model. Measured debris impactor fluxes are in good agreement with the model for ram surfaces. However, predictions of the model for other surfaces of a spacecraft are less accurate, most notably for the wake or trailing side. While the Kessler model is appropriate for long-term, average flux predictions, spatial-temporal impact fluxes measured on LDEF dramatically illustrated the presence of strong debris clouds that do not dissipate quickly in space and will encounter an orbiting spacecraft cyclically and repeatedly over its lifetime. LDEF data has also indicated the presence of debris in elliptical orbits, a fact not predicted by the Kessler model. This fact is responsible for the discrepancy between measured impact fluxes and predictions on trailing edge surfaces.

  15. Mixed debris treatment at the Idaho National Engineering Laboratory (INEL)

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, E.C. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Porter, C.L. [Westinghouse Idaho Nuclear Co., Inc., Idaho Falls, ID (United States); Wallace, M.T. [Argonne National Lab., Idaho Falls, ID (United States)

    1993-10-01

    August 18, 1992 the Environmental Protection Agency (EPA) published the final revised treatment standards for hazardous debris, including mixed debris. (1) Whereas previous standards had been concentration based, the revised standards are performance based. Debris must be treated prior to land disposal, using specific technologies from one or more of the following families of debris treatment technologies: Extraction, destruction, or immobilization. Seventeen specific technologies with generic application are discussed in the final rule. The existing capabilities and types of debris at the INEL were scrubbed against the debris rule to determine an overall treatment strategy. Seven types of debris were identified: combustible, porous, non-porous, inherently hazardous, HEPA filters, asbestos contaminated, and reactive metals contaminated debris. With the exception of debris contaminated with reactive metals treatment can be achieved utilizing existing facilities coupled with minor modifications.

  16. Linking social drivers of marine debris with actual marine debris on beaches.

    Science.gov (United States)

    Slavin, Chris; Grage, Anna; Campbell, Marnie L

    2012-08-01

    The drivers (social) and pressures (physical) of marine debris have typically been examined separately. We redress this by using social and beach surveys at nine Tasmanian beaches, across three coastlines and within three categories of urbanisation, to examine whether people acknowledge that their actions contribute to the issue of marine debris, and whether these social drivers are reflected in the amount of marine debris detected on beaches. A large proportion (75%) of survey participants do not litter at beaches; with age, gender, income and residency influencing littering behaviour. Thus, participants recognise that littering at beaches is a problem. This social trend was reflected in the small amounts of debris that were detected. Furthermore, the amount of debris was not statistically influenced by the degree of beach urbanisation, the coastline sampled, or the proximity to beach access points. By linking social and physical aspects of this issue, management outcomes can be improved.

  17. Surface characteristics of debris-covered glacier tongues in the Khumbu Himalaya derived from remote sensing texture analysis

    Science.gov (United States)

    Racoviteanu, Adina; Arnaud, Yves; Nicholson, Lindsay

    2013-04-01

    The delineation of debris-covered glaciers remains a challenge in optical remote sensing, due to the similarity of the spectral signature of debris-covered ice to surrounding lateral moraines, making it difficult to apply standard semi-automated algorithms commonly used for clean ice delineation. Furthermore, supraglacial debris exhibits considerable spatial variability in its characteristics such as debris cover thickness, particle size, thermal resistance and thermal conductivity. These properties are needed in order to map the extent of debris cover and to estimate ice melt under the debris cover or at the surface. In this study we evaluate the potential of texture analysis for detecting surface characteristics of debris-cover glacier tongues in the Khumbu Himalaya, using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and high-resolution Ikonos data. We focus on mapping supra-glacier lakes and exposed ice walls using texture analysis algorithms such as grey-level co-occurrence measures (GLCM), filtering, image segmentation, and particle boundaries. We compare the performance of various existing commercial software suitable for texture analysis such as ERDAS Objective, Aphelion, as well as public domain image display and analysis software used originally for medical analysis, notably Image SXM and ImageJ. Preliminary results based on geostatistics and GLCM measures show differences in surface roughness of debris cover when compared to surrounding ice-free moraines. We expand on these results and aim at developing a quasi-automated algorithm for extracting surface features, which will be used as input in an energy balance model for estimating melting under debris cover as well as surface ice melt.

  18. LightForce Photon-Pressure Collision Avoidance: Efficiency Assessment on an Entire Catalogue of Space Debris

    Science.gov (United States)

    Stupl, J.; Faber, N.; Foster, C.; Yang, F.; Levit, C.

    2013-09-01

    The potential to perturb debris orbits using photon pressure from ground-based lasers has been confirmed by independent research teams. Useful applications of this scheme are protecting space assets from impacts with debris and stabilizing the orbital debris environment, both relying on collision avoidance rather than de-orbiting debris. This paper presents the results of a new assessment method to analyze the efficiency of the concept. Earlier research concluded that one ground based system consisting of a 10 kW class laser, directed by a 1.5 m telescope with adaptive optics, can avoid a significant fraction of debris-debris collisions in low Earth orbit. That research used in-track displacement to measure efficiency and restricted itself to an analysis of a limited number of objects. As orbit prediction error is dependent on debris object properties, a static displacement threshold should be complemented with another measure to assess the efficiency of the scheme. In this paper we present the results of an approach using probability of collision. Using a least-squares fitting method, we improve the quality of the original TLE catalogue in terms of state and co-state accuracy. We then calculate collision probabilities for all the objects in the catalogue. The conjunctions with the highest risk of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the collision probability in a 24h window around the original conjunction. We then use different criteria to evaluate the utility of the laser based collision avoidance scheme and assess the number of base-line ground stations needed to mitigate a significant number of high probability conjunctions. Finally, we also give an account how a laser ground station can be used for both orbit deflection and debris tracking.

  19. Isotopes. Veritas in vino. [Vintage wines produced useful data of nuclear fallout and levels of natural tritium

    Energy Technology Data Exchange (ETDEWEB)

    Verhagen, B. Th. (University of the Witwatersrand, Johannesburg (South Africa). Nuclear Physics Research Unit); Nichola, A.

    1982-07-01

    Vintage wines, provide useful dated samples of atmospheric water from which the history of nuclear fallout and the levels of natural tritium before the nuclear test period can be reconstructed. As a result of the study, there is now a much improved estimate of the pre-bomb tritium level which is of importance for hydrological studies and estimating the cosmic ray production rate.

  20. Fallout volume and litter type affect (137)Cs concentration difference in litter between forest and stream environments.

    Science.gov (United States)

    Sakai, Masaru; Gomi, Takashi; Negishi, Junjiro N

    2016-11-01

    It is important to understand the changes in the (137)Cs concentration in litter through leaching when considering that (137)Cs is transferred from basal food resources to animals in forested streams. We found that the difference of (137)Cs activity concentration in litter between forest and stream was associated with both litter type and (137)Cs fallout volume around Fukushima, Japan. The (137)Cs activity concentrations in the litter of evergreen conifers tended to be greater than those in the litter of broad-leaved deciduous trees because of the absence of deciduous leaves during the fallout period in March 2011. Moreover, (137)Cs activity concentrations in forest litter were greater with respect to the (137)Cs fallout volume. The (137)Cs activity concentrations in stream litter were much lower than those in forest litter when those in forest litter were higher. The (137)Cs leaching patterns indicated that the differences in (137)Cs activity concentration between forest and stream litter could change with changes in both fallout volume and litter type. Because litter is an important basal food resource in the food webs of both forests and streams, the (137)Cs concentration gradient reflects to possible (137)Cs transfer from lower to higher trophic animals. Our findings will improve our understanding of the spatial heterogeneity and variability of (137)Cs concentrations in animals resident to the contaminated landscape.

  1. Chernobyl Nuclear Reactor accident fallout: Measurement and consequences. (Latest citations from the NTIS bibliographic database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    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)

  2. Health and Safety Laboratory environmental quarterly. Final tabulation of monthly /sup 90/Sr fallout data: 1954--1976

    Energy Technology Data Exchange (ETDEWEB)

    1977-10-01

    This report presents the monthly /sup 90/Sr deposition data derived from a global network of stations started in 1954. This program was carried out to assess the distribution patterns and inventory the amount of fallout of radionuclies from atmospheric nuclear tests. In 1976, monthly deposition rates had diminished to the point where measurable levels of /sup 90/Sr were rarely observed.

  3. Appendix to Health and Safety Laboratory environmental quarterly, June 1, 1976--September 1, 1976. [Fallout radionuclides and Pb in environment

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, E.P. Jr.

    1976-10-01

    Tabulated data are presented on the content of /sup 90/Sr and /sup 89/Sr in fallout deposited at various world land sites; /sup 90/Sr in milk and drinking water samples from various locations; and the content of Pb in samples of surface air. (CH)

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

    Science.gov (United States)

    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…

  5. Orphan Sources and Fresh Fallout: Virtual Exercise in Mobile Measurement (ORPEX)

    Energy Technology Data Exchange (ETDEWEB)

    Dowdall, M. (Norwegian Radiation Protection Authority, OEsteraas (Norway)); Smethurst, M.A. (Univ. of Exeter and Avalonia Geophysics, Cornwall Campus, Penryn (United Kingdom)); Andersson, K. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Aage, H.K. (Danish Emergency Management Agency, Birkeroed (Denmark)); Palsson, S.E. (Icelandic Radiation Protection Institute, Reykjavik (Iceland))

    2011-10-15

    In recent years carborne gamma spectrometry has expanded from its role as a geological survey platform to serving as a useful asset in the field of emergency response to radiological and nuclear situations. Its two main applications are searching for orphan sources and for surveying in the aftermath of an accident involving the release of radioactive materials. Despite this expansion, the opportunities for gaining practical experience in the field are limited by cost considerations and practicability. These limitations are exacerbated by the fact that data generated and displayed in the field differ significantly from gamma spectral data generated in a laboratory environment. As a means of exercising existing emergency measuring/surveying capability and introducing carborne measurements to a larger group, a virtual exercise was devised. The exercise ORPEX (Orphan Sources and Fresh Fallout Virtual Exercise in Mobile Measurement) featured two typical emergency scenarios in which carborne measuring systems might be deployed: firstly a search for multiple orphan sources and secondly surveying to delineate patchy fallout from a local release point. In the first scenario, synthetic spectral data were generated for imaginary point sources and inserted into genuine carborne measurements from in the Trondheim area of Norway. Participants were presented with a typical software tool and data in a range of typical formats and asked to report the source locations and isotopes within a time limit. In the second scenario, synthetic spectral data representing fallout from a local fire involving radioactive material were added to real carborne data from the Trondheim area. Participants were asked to produce maps that identify and characterise the regions of contamination within the same time limit. Fourteen individual organisations from seven different countries supplied results. Results from participants indicate that for strong sources of isotopes with simple spectra featuring

  6. Catastrophic debris flows transformed from landslides in volcanic terrains : mobility, hazard assessment and mitigation strategies

    Science.gov (United States)

    Scott, Kevin M.; Macias, Jose Luis; Naranjo, Jose Antonio; Rodriguez, Sergio; McGeehin, John P.

    2001-01-01

    Communities in lowlands near volcanoes are vulnerable to significant volcanic flow hazards in addition to those associated directly with eruptions. The largest such risk is from debris flows beginning as volcanic landslides, with the potential to travel over 100 kilometers. Stratovolcanic edifices commonly are hydrothermal aquifers composed of unstable, altered rock forming steep slopes at high altitudes, and the terrain surrounding them is commonly mantled by readily mobilized, weathered airfall and ashflow deposits. We propose that volcano hazard assessments integrate the potential for unanticipated debris flows with, at active volcanoes, the greater but more predictable potential of magmatically triggered flows. This proposal reinforces the already powerful arguments for minimizing populations in potential flow pathways below both active and selected inactive volcanoes. It also addresses the potential for volcano flank collapse to occur with instability early in a magmatic episode, as well as the 'false-alarm problem'-the difficulty in evacuating the potential paths of these large mobile flows. Debris flows that transform from volcanic landslides, characterized by cohesive (muddy) deposits, create risk comparable to that of their syneruptive counterparts of snow and ice-melt origin, which yield noncohesive (granular) deposits, because: (1) Volcano collapses and the failures of airfall- and ashflow-mantled slopes commonly yield highly mobile debris flows as well as debris avalanches with limited runout potential. Runout potential of debris flows may increase several fold as their volumes enlarge beyond volcanoes through bulking (entrainment) of sediment. Through this mechanism, the runouts of even relatively small collapses at Cascade Range volcanoes, in the range of 0.1 to 0.2 cubic kilometers, can extend to populated lowlands. (2) Collapse is caused by a variety of triggers: tectonic and volcanic earthquakes, gravitational failure, hydrovolcanism, and

  7. Small craters on the meteoroid and space debris impact experiment

    Science.gov (United States)

    Humes, Donald H.

    1995-01-01

    Examination of 9.34 m(exp 2) of thick aluminum plates from the Long Duration Exposure Facility (LDEF) using a 25X microscope revealed 4341 craters that were 0.1 mm in diameter or larger. The largest was 3 mm in diameter. Most were roughly hemispherical with lips that were raised above the original plate surface. The crater diameter measured was the diameter at the top of the raised lips. There was a large variation in the number density of craters around the three-axis gravity-gradient stabilized spacecraft. A model of the near-Earth meteoroid environment is presented which uses a meteoroid size distribution based on the crater size distribution on the space end of the LDEF. An argument is made that nearly all the craters on the space end must have been caused by meteoroids and that very few could have been caused by man-made orbital debris. However, no chemical analysis of impactor residue that will distinguish between meteoroids and man-made debris is yet available. A small area (0.0447 m(exp 2)) of one of the plates on the space end was scanned with a 200X microscope revealing 155 craters between 10 micron and 100 micron in diameter and 3 craters smaller than 10 micron. This data was used to extend the size distribution of meteoroids down to approximately 1 micron. New penetration equations developed by Alan Watts were used to relate crater dimensions to meteoroid size. The equations suggest that meteoroids must have a density near 2.5 g/cm(exp 3) to produce craters of the shape found on the LDEF. The near-Earth meteoroid model suggests that about 80 to 85 percent of the 100 micron to 1 mm diameter craters on the twelve peripheral rows of the LDEF were caused by meteoroids, leaving 15 to 20 percent to be caused by man-made orbital debris.

  8. Debris-flow mobilization from landslides

    Science.gov (United States)

    Iverson, R.M.; Reid, M.E.; LaHusen, R.G.

    1997-01-01

    Field observations, laboratory experiments, and theoretical analyses indicate that landslides mobilize to form debris flows by three processes: (a) widespread Coulomb failure within a sloping soil, rock, or sediment mass, (b) partial or complete liquefaction of the mass by high pore-fluid pressures, and (c) conversion of landslide translational energy to internal vibrational energy (i.e. granular temperature). These processes can operate independently, but in many circumstances they appear to operate simultaneously and synergistically. Early work on debris-flow mobilization described a similar interplay of processes but relied on mechanical models in which debris behavior was assumed to be fixed and governed by a Bingham or Bagnold rheology. In contrast, this review emphasizes models in which debris behavior evolves in response to changing pore pressures and granular temperatures. One-dimensional infinite-slope models provide insight by quantifying how pore pressures and granular temperatures can influence the transition from Coulomb failure to liquefaction. Analyses of multidimensional experiments reveal complications ignored in one-dimensional models and demonstrate that debris-flow mobilization may occur by at least two distinct modes in the field.

  9. Laser Systems for Orbital Debris Removal

    Energy Technology Data Exchange (ETDEWEB)

    Rubenchik, A M; Barty, C P; Beach, R J; Erlandson, A C; Caird, J A

    2010-02-05

    The use of a ground based laser for space debris cleaning was investigated by the ORION project in 1996. Since that study the greatest technological advance in the development of high energy pulsed laser systems has taken place within the NIF project at LLNL. The proposed next laser system to follow the NIF at LLNL will be a high rep rate version of the NIF based on diode-pumping rather than flashlamp excitation; the so called 'LIFE' laser system. Because a single 'LIFE' beamline could be built up in a few year time frame, and has performance characteristics relevant to the space debris clearing problem, such a beamline could enable a near term demonstration of space debris cleaning. Moreover, the specifics of debris cleaning make it possible to simplify the LIFE laser beyond what is required for a fusion drive laser, and so substantially reduce its cost. Starting with the requirements for laser intensity on the target, and then considering beam delivery, we will flow back the laser requirements needed for space debris cleaning. Using these derived requirements we will then optimize the pulse duration, the operational regime, and the output pulse energy of the laser with a focus of simplifying its overall design. Anticipated simplifications include operation in the heat capacity regime, eliminating cooling requirements on the laser gain slabs, and relaxing B-integral and birefrigence requirements.

  10. Space Debris Reentry Analysis Methods and Tools

    Institute of Scientific and Technical Information of China (English)

    WU Ziniu; HU Ruifeng; QU Xi; WANG Xiang; WU Zhe

    2011-01-01

    The reentry of uncontrolled spacecraft may be broken into many pieces of debris at an altitude in the range of 75-85 km.The surviving fragments could pose great hazard and risk to ground and people.In recent years,methods and tools for predicting and analyzing debris reentry and ground risk assessment have been studied and developed in National Aeronautics and Space Administration(NASA),European Space Agency(ESA) and other organizations,including the group of the present authors.This paper reviews the current progress on this topic of debris reentry briefly.We outline the Monte Carlo method for uncertainty analysis,breakup prediction,and parameters affecting survivability of debris.The existing analysis tools can be classified into two categories,i.e.the object-oriented and the spacecraft-oriented methods,the latter being more accurate than the first one.The past object-oriented tools include objects of only simple shapes.For more realistic simulation,here we present an object-oriented tool debris reentry and ablation prediction system(DRAPS) developed by the present authors,which introduces new object shapes to 15 types,as well as 51 predefined motions and relevant aerodynamic and aerothermal models.The aerodynamic and aerothermal models in DRAPS are validated using direct simulation Monte Carlo(DSMC) method.

  11. Development of the town data base: Estimates of exposure rates and times of fallout arrival near the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C.B.; McArthur, R.D. [Univ. and Community College System of Nevada, Las Vegas, NV (United States); Hutchinson, S.W. [Mead Johnson Nutritional Group, Evansville, IN (United States)

    1994-09-01

    As part of the U.S. Department of Energy`s Off-Site Radiation Exposure Review Project, the time of fallout arrival and the H+12 exposure rate were estimated for populated locations in Arizona, California, Nevada, and Utah that were affected by fallout from one or more nuclear tests at the Nevada Test Site. Estimates of exposure rate were derived from measured values recorded before and after each test by fallout monitors in the field. The estimate for a given location was obtained by retrieving from a data base all measurements made in the vicinity, decay-correcting them to H+12, and calculating an average. Estimates were also derived from maps produced after most events that show isopleths of exposure rate and time of fallout arrival. Both sets of isopleths on these maps were digitized, and kriging was used to interpolate values at the nodes of a 10-km grid covering the pattern. The values at any location within the grid were then estimated from the values at the surrounding grid nodes. Estimates of dispersion (standard deviation) were also calculated. The Town Data Base contains the estimates for all combinations of location and nuclear event for which the estimated mean H+12 exposure rate was greater than three times background. A listing of the data base is included as an appendix. The information was used by other project task groups to estimate the radiation dose that off-site populations and individuals may have received as a result of exposure to fallout from Nevada nuclear tests.

  12. Early detection of radioactive fall-out by gamma-spectrometry

    DEFF Research Database (Denmark)

    Aage, Helle Karina; Korsbech, Uffe C C; Bargholz, K.

    2003-01-01

    Radioactive fallout should be detected as early as possible. A new and efficient method for detection of low-level irradiation from manmade radioactivity is developed. Radiation abnormalities are detectable down to air kerma rate, of 0.5 to 1.0 nGy h(-1) for Cs-137 and even lower for I-131...... For multi-gamma energy radioactivity the detection level is 2.6-3.5 nGy h(-1). A standard NaI detector and a 512-channel analyser are used together with noise adjusted singular value decomposition (NASVD). Statistical noise is removed and the measured spectra are reproduced using spectral components...... radioactive sources need to be detected....

  13. The influence of forest shelterbelts on 137Cs fallout in Chernobyl affected areas (Tula region, Russia).

    Science.gov (United States)

    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

  14. New simple deposition model based on reassessment of global fallout data 1954 – 1976

    DEFF Research Database (Denmark)

    Pálsson, Sigurður Emil; Bergan, Tone D.; Howard, Brenda J.;

    by not assuming the traditional proportional relationship, but instead a non-linear power function. The predictions obtained using this new model may not be significantly different from those obtained using the traditional model, when using a limited data set such as from one country as a test in this report...... showed. But for larger data sets and understanding of underlying processes the new model should be an improvement....... such as (a) over how large area can it be assumed that the concentration in precipitation is the same at any given time; (b) how does this agree with the observed latitude dependency of deposition density and (c) are the any other parameters that could be of use in a simple model describing global fallout...

  15. Spatiotemporal Variation of Particulate Fallout Instances in Sfax City, Southern Tunisia: Influence of Sources and Meteorology

    Directory of Open Access Journals (Sweden)

    Moez Bahloul

    2015-01-01

    Full Text Available Particles deposition in the main industrial zone of Sfax City (southern Tunisia was studied by weekly monitoring particulate fallout instances at twenty sites from November 11, 2012, to April 15, 2013. Very high fluctuation in those particle fluxes, ranging from 0.376 to 9.915 g/m2, was clearly observed. Spatiotemporal distribution of the deposited particulate fluxes and the exposure of each site to the main industrial plumes (i.e., phosphate treatment plant “SIAPE,” soap industry “SIOS-ZITEX,” and lead secondary melting industry “FP Sfax Sud” indicated the concomitant effects of surrounding industrial sources. In addition, the highest particulate deposition seemed to be associated with predominant strong cyclonic situations. Those deposition rates exceeded the levels recorded in the case of strong stabilities, considered as responsible for pollutant accumulation.

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

    DEFF Research Database (Denmark)

    Qiao, Jixin; Steier, Peter; Nielsen, Sven Poul

    2017-01-01

    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...... 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...

  17. Medical status of Marshallese accidentally exposed to 1954 Bravo fallout radiation, January 1983-December 1984

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Controls on debris flow bulking in proglacial gully networks on Mount Rainier, WA

    Science.gov (United States)

    Legg, N. T.; Meigs, A.; Grant, G. E.; Kennard, P.

    2012-12-01

    Conversion of floodwaters to debris flows due to sediment bulking continues to be a poorly understood phenomenon. This study examines the initiation zone of a series of six debris flows that originated in proglacial areas of catchments on the flank of Mount Rainier during one storm in 2006. One-meter spatial resolution aerial photographs and LiDAR DEMs acquired before and after the storm reveal the lack of a single mass failure to explain the debris flow deposits. Rather, the imagery show appreciable gully widening along reaches up to approximately 1.5 km in length. Based on gully discharges estimated from rainfall rates and estimates of sediment contribution from gully wall width change, we find that the sediment volumes contributed from gully walls are sufficient to bulk floodwaters up to debris flow concentrations. Points in gullies where width change began (upstream limit) in 2006 have a power law trend (R2 = 0.58) in terms of slope-drainage area. Reaches with noticeable width change, which we refer to as bulking reaches (BR), plot along a similar trend with greater drainage areas and gentler slopes. We then extracted slope and drainage area of all proglacial drainage networks to examine differences in morphology between debris flow basins (DFB) and non-debris flow basins (NDFB), hypothesizing that DFB would have a greater portion of their drainage networks with similar morphology to BR than NDFB. A comparison of total network length with greater slope and area than BR reveals that the two basins types are not statistically different. Lengths of the longest reaches with greater slope and drainage area than the BR trend, however, are statistically longer in DFB than in the NDFBs (p<0.05). These results suggest that debris flow initiation by sediment bulking does not operate as a simple threshold phenomenon in slope-area space. Instead debris flow initiation via bulking depends upon slope, drainage area, and gully length. We suspect the dependence on length

  19. Amplification of postwildfire peak flow by debris

    Science.gov (United States)

    Kean, J. W.; McGuire, L. A.; Rengers, F. K.; Smith, J. B.; Staley, D. M.

    2016-08-01

    In burned steeplands, the peak depth and discharge of postwildfire runoff can substantially increase from the addition of debris. Yet methods to estimate the increase over water flow are lacking. We quantified the potential amplification of peak stage and discharge using video observations of postwildfire runoff, compiled data on postwildfire peak flow (Qp), and a physically based model. Comparison of flood and debris flow data with similar distributions in drainage area (A) and rainfall intensity (I) showed that the median runoff coefficient (C = Qp/AI) of debris flows is 50 times greater than that of floods. The striking increase in Qp can be explained using a fully predictive model that describes the additional flow resistance caused by the emergence of coarse-grained surge fronts. The model provides estimates of the amplification of peak depth, discharge, and shear stress needed for assessing postwildfire hazards and constraining models of bedrock incision.

  20. Signatures of massive collisions in debris discs

    CERN Document Server

    Kral, Quentin; Augereau, Jean-Charles; Boccaletti, Anthony; Charnoz, Sebastien

    2014-01-01

    Violent stochastic collisional events have been invoked as a possible explanation for some debris discs displaying pronounced asymmetries or having a great luminosity excess. So far, no thorough modelling of the consequences of such events has been carried out, mainly because of the extreme numerical challenge of coupling the dynamical and collisional evolution of dust. We perform the first fully self-consistent modelling of the aftermath of massive breakups in debris discs. We follow the collisional and dynamical evolution of dust released after the breakup of a Ceres-sized body at 6 AU from its central star. We investigate the duration, magnitude and spatial structure of the signature left by such a violent event, as well as its observational detectability. We use the recently developed LIDT-DD code (Kral et al., 2013), which handles the coupled collisional and dynamical evolution of debris discs. The main focus is placed on the complex interplay between destructive collisions, Keplerian dynamics and radiat...

  1. Parametric analysis: SOC meteoroid and debris protection

    Science.gov (United States)

    Kowalski, R.

    1985-01-01

    The meteoroid and man made space debris environments of an Earth orbital manned space operations center are discussed. Protective shielding thickness and design configurations for providing given levels of no penetration probability were also calculated. Meteoroid/debris protection consists of a radiator/shield thickness, which is actually an outer skin, separated from the pressure wall, thickness by a distance. An ideal shield thickness, will, upon impact with a particle, cause both the particle and shield to vaporize, allowing a minimum amount of debris to impact the pressure wall itself. A shield which is too thick will crater on the outside, and release small particles of shield from the inside causing damage to the pressure wall. Inversely, if the shield is too thin, it will afford no protection, and the backup must provide all necessary protection. It was concluded that a double wall concept is most effective.

  2. Clumps and Axisymmetric Features in Debris Discs

    CERN Document Server

    Jiang, Ing-Guey

    2013-01-01

    This paper studied the structures of debris discs, focusing on the conditions that can form an axisymmetric-looking outer disc from systems with inner clumps. The main conclusion was that as long as the dominated dust grains are smaller than the blowout size, it is easy to form an axisymmetric-looking outer debris disc, which is part of a quasi-steady state of the whole system. This quasi-steady state is established through the balance between grain generations and a continuous out-going grain flow. Assuming there is an event that starts planetesimal collisions and the corresponding grain generations, this balance can be approached in a few thousand years. This result suggested that a quasi-steady-state picture could solve the possible mass budget problem of Vega's outer debris disc.

  3. Debris flow hazards mitigation--Mechanics, prediction, and assessment

    Science.gov (United States)

    Chen, C.-L.; Major, J.J.

    2007-01-01

    These proceedings contain papers presented at the Fourth International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment held in Chengdu, China, September 10-13, 2007. The papers cover a wide range of topics on debris-flow science and engineering, including the factors triggering debris flows, geomorphic effects, mechanics of debris flows (e.g., rheology, fluvial mechanisms, erosion and deposition processes), numerical modeling, various debris-flow experiments, landslide-induced debris flows, assessment of debris-flow hazards and risk, field observations and measurements, monitoring and alert systems, structural and non-structural countermeasures against debris-flow hazards and case studies. The papers reflect the latest devel-opments and advances in debris-flow research. Several studies discuss the development and appli-cation of Geographic Information System (GIS) and Remote Sensing (RS) technologies in debris-flow hazard/risk assessment. Timely topics presented in a few papers also include the development of new or innovative techniques for debris-flow monitoring and alert systems, especially an infra-sound acoustic sensor for detecting debris flows. Many case studies illustrate a wide variety of debris-flow hazards and related phenomena as well as their hazardous effects on human activities and settlements.

  4. Dose assessment for sheep exposed to fallout from nuclear test Nancy

    Energy Technology Data Exchange (ETDEWEB)

    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. Rainfall erosivity in catchments contaminated with fallout from the Fukushima Daiichi nuclear power plant accident

    Science.gov (United States)

    Laceby, J. Patrick; Chartin, Caroline; Evrard, Olivier; Onda, Yuichi; Garcia-Sanchez, Laurent; Cerdan, Olivier

    2016-06-01

    The Fukushima Daiichi nuclear power plant (FDNPP) accident in March 2011 resulted in the fallout of significant quantities of radiocesium over the Fukushima region. After reaching the soil surface, radiocesium is quickly bound to fine soil particles. Thereafter, rainfall and snowmelt run-off events transfer particle-bound radiocesium downstream. Characterizing the precipitation regime of the fallout-impacted region is thus important for understanding post-deposition radiocesium dynamics. Accordingly, 10 min (1995-2015) and daily precipitation data (1977-2015) from 42 meteorological stations within a 100 km radius of the FDNPP were analyzed. Monthly rainfall erosivity maps were developed to depict the spatial heterogeneity of rainfall erosivity for catchments entirely contained within this radius. The mean average precipitation in the region surrounding the FDNPP is 1420 mm yr-1 (SD 235) with a mean rainfall erosivity of 3696 MJ mm ha-1 h-1 yr-1 (SD 1327). Tropical cyclones contribute 22 % of the precipitation (422 mm yr-1) and 40 % of the rainfall erosivity (1462 MJ mm ha-1 h-1 yr-1 (SD 637)). The majority of precipitation (60 %) and rainfall erosivity (82 %) occurs between June and October. At a regional scale, rainfall erosivity increases from the north to the south during July and August, the most erosive months. For the remainder of the year, this gradient occurs mostly from northwest to southeast. Relief features strongly influence the spatial distribution of rainfall erosivity at a smaller scale, with the coastal plains and coastal mountain range having greater rainfall erosivity than the inland Abukuma River valley. Understanding these patterns, particularly their spatial and temporal (both inter- and intraannual) variation, is important for contextualizing soil and particle-bound radiocesium transfers in the Fukushima region. Moreover, understanding the impact of tropical cyclones will be important for managing sediment and sediment-bound contaminant

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

    Science.gov (United States)

    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.

  7. Effect of perturbations on debris-to-debris orbital transfers: A quantitative analysis

    Science.gov (United States)

    Kumar, Kartik; Hekma, Enne; Agrawal, Abhishek; Topputo, Francesco

    2017-03-01

    We investigated the applicability of the Lambert solver (Izzo, 2014) for preliminary design of Multi-Target Active Debris Removal missions. Firstly, we computed ≈25 million debris-to-debris transfers using the Lambert solver for selected sets of debris objects in Low Earth Orbit, Geostationary Transfer Orbit, and Geosynchronous Orbit. Subsequently, we propagated the departure states of the Lambert transfers below selected ΔV cut-offs using the SGP4/SDP4 propagator (Vallado et al., 2006). We recorded the arrival position and velocity error vectors incurred by neglecting perturbations and analyzed the results for each orbital regime. Our results indicate that perturbations can play a significant role in determining the feasibility of debris-to-debris transfers. By using the Lambert solver and neglecting perturbations, the errors in the arrival position and velocity for individual legs can be large. The largest errors were obtained for transfers between debris objects in Sun-Synchronous Orbit (O (100) km error in magnitude of position vector and O (0.1) km/s error in magnitude of velocity vector). Hence, solely employing the Lambert solver to rank transfer legs could lead to incorrect choices for sequencing of multi-target trajectories. This is particularly relevant for transfers in Low Earth Orbit, where the effects of perturbations are the strongest.

  8. Dust production in debris discs: constraints on the smallest grains

    CERN Document Server

    Thebault, Philippe

    2016-01-01

    The surface energy constraint puts a limit on the smallest fragment $s_{surf}$ that can be produced after a collision. Based on analytical considerations, this mechanism has been recently identified as been potentially able to prevent the production of small dust grains in debris discs and cut off their size distribution at sizes larger than the blow-out size. We numerically investigate the importance of this effect to find under which conditions it can leave a signature in the small-size end of a disc's particle size distribution (PSD). An important part of this work is to map out, in a disc at steady-state, what is the most likely collisional origin for micron-sized grains, in terms of the sizes of their collisional progenitors. We implement, for the first time, the surface energy constraint into a collisional evolution code. We consider a debris disc extending from 50 to 100AU and 2 different stellar types. We also consider two levels of stirring in the disc: dynamically "hot" (e=0.075) and "cold" (e=0.01)...

  9. Converging posterior distributions in space debris monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Lasanen, Sari [Department of Mathematical Sciences, University of Oulu, 90014 University of Oulu (Finland)], E-mail: sari.lasanen@oulu.fi

    2008-11-01

    Ground-based radars monitor the falling space debris in order to prevent collisions with spacecrafts and satellites. Experiments with European Incoherent Scatter (EISCAT) Scientific Association radars using new data acquisition equipment suitable for space debris detection have raised a question what happens to a Bayesian solution when the sampling frequency of the reflected signal is increased. Assuming slightly idealized measurements, we show that the posterior densities converge in this case. This shows that the sampling method suits well for the statistical inverse problem.

  10. Apparatus for controlling molten core debris. [LMFBR

    Science.gov (United States)

    Golden, M.P.; Tilbrook, R.W.; Heylmun, N.F.

    1977-07-19

    Disclosed is an apparatus for containing, cooling, diluting, dispersing and maintaining subcritical the molten core debris assumed to melt through the bottom of a nuclear reactor pressure vessel in the unlikely event of a core meltdown. The apparatus is basically a sacrificial bed system which includes an inverted conical funnel, a core debris receptacle including a spherical dome, a spherically layered bed of primarily magnesia bricks, a cooling system of zig-zag piping in graphite blocks about and below the bed and a cylindrical liner surrounding the graphite blocks including a steel shell surrounded by firebrick. Tantalum absorber rods are used in the receptacle and bed. 9 claims, 22 figures.

  11. Density Estimations in Laboratory Debris Flow Experiments

    Science.gov (United States)

    Queiroz de Oliveira, Gustavo; Kulisch, Helmut; Malcherek, Andreas; Fischer, Jan-Thomas; Pudasaini, Shiva P.

    2016-04-01

    Bulk density and its variation is an important physical quantity to estimate the solid-liquid fractions in two-phase debris flows. Here we present mass and flow depth measurements for experiments performed in a large-scale laboratory set up. Once the mixture is released and it moves down the inclined channel, measurements allow us to determine the bulk density evolution throughout the debris flow. Flow depths are determined by ultrasonic pulse reflection, and the mass is measured with a total normal force sensor. The data were obtained at 50 Hz. The initial two phase material was composed of 350 kg debris with water content of 40%. A very fine pebble with mean particle diameter of 3 mm, particle density of 2760 kg/m³ and bulk density of 1400 kg/m³ in dry condition was chosen as the solid material. Measurements reveal that the debris bulk density remains high from the head to the middle of the debris body whereas it drops substantially at the tail. This indicates lower water content at the tail, compared to the head and the middle portion of the debris body. This means that the solid and fluid fractions are varying strongly in a non-linear manner along the flow path, and from the head to the tail of the debris mass. Importantly, this spatial-temporal density variation plays a crucial role in determining the impact forces associated with the dynamics of the flow. Our setup allows for investigating different two phase material compositions, including large fluid fractions, with high resolutions. The considered experimental set up may enable us to transfer the observed phenomena to natural large-scale events. Furthermore, the measurement data allows evaluating results of numerical two-phase mass flow simulations. These experiments are parts of the project avaflow.org that intends to develop a GIS-based open source computational tool to describe wide spectrum of rapid geophysical mass flows, including avalanches and real two-phase debris flows down complex natural

  12. TRAC laboratory monitoring of Chernobyl radioactive debris

    Energy Technology Data Exchange (ETDEWEB)

    Sigg, R.A.

    1986-06-09

    A severe accident occurred at the Chernobyl nuclear power plant number 4 in the Soviet Union on April 25, 1986. An explosion released large amounts of radioactive debris, primarily fission products, to the atmosphere. As winds carried debris from the Soviet Union, scientists in Europe and the United States reported detecting fission product activities in air samples. Monitoring by the Tracking Radioactive Atmospheric Contaminants (TRAC) mobile laboratory showed concentrations in the Southeastern United States were well below those considered hazardous. This document provides details of this monitoring effort.

  13. Patterns In Debris Disks: No Planets Required?

    Science.gov (United States)

    Kuchner, Marc

    2012-01-01

    Debris disks like those around Fomalhaut and Beta Pictoris show striking dust patterns often attributed to hidden exoplanets. These patterns have been crucial for constraining the masses and orbits of these planets. But adding a bit of gas to our models of debris disks--too little gas to detect--seems to alter this interpretation. Small amounts of gas lead to new dynamical instabilities that may mimic the narrow eccentric rings and other structures planets would create in a gas-free disk. Can we still use dust patterns to find hidden exoplanets?

  14. Discrete Element Modelling of Floating Debris

    Science.gov (United States)

    Mahaffey, Samantha; Liang, Qiuhua; Parkin, Geoff; Large, Andy; Rouainia, Mohamed

    2016-04-01

    Flash flooding is characterised by high velocity flows which impact vulnerable catchments with little warning time and as such, result in complex flow dynamics which are difficult to replicate through modelling. The impacts of flash flooding can be made yet more severe by the transport of both natural and anthropogenic debris, ranging from tree trunks to vehicles, wheelie bins and even storage containers, the effects of which have been clearly evident during recent UK flooding. This cargo of debris can have wide reaching effects and result in actual flood impacts which diverge from those predicted. A build-up of debris may lead to partial channel blockage and potential flow rerouting through urban centres. Build-up at bridges and river structures also leads to increased hydraulic loading which may result in damage and possible structural failure. Predicting the impacts of debris transport; however, is difficult as conventional hydrodynamic modelling schemes do not intrinsically include floating debris within their calculations. Subsequently a new tool has been developed using an emerging approach, which incorporates debris transport through the coupling of two existing modelling techniques. A 1D hydrodynamic modelling scheme has here been coupled with a 2D discrete element scheme to form a new modelling tool which predicts the motion and flow-interaction of floating debris. Hydraulic forces arising from flow around the object are applied to instigate its motion. Likewise, an equivalent opposing force is applied to fluid cells, enabling backwater effects to be simulated. Shock capturing capabilities make the tool applicable to predicting the complex flow dynamics associated with flash flooding. The modelling scheme has been applied to experimental case studies where cylindrical wooden dowels are transported by a dam-break wave. These case studies enable validation of the tool's shock capturing capabilities and the coupling technique applied between the two numerical

  15. Debris Flow Dam Formation in Southeast Tibet

    Institute of Scientific and Technical Information of China (English)

    CHENG Zunlan; WU Jishan; GENG Xueyong

    2005-01-01

    Glaciers with their deposits abound in the alpine areas of Southeast Tibet. Large debris flows occur frequently from these deposits and form dams that block streams. In this paper, 3 events of large debris flows reported in Peilong Valley located in Southeast Tibet, and which resulted 2 blocking dams resulted, are discussed in details, focusing on the major factors controlling dam formation. The results shows that the first surge group caused by snow and ice avalanches, ice-lake breaks, and large-scale landslides, with a high peak discharge and high velocity, and an abundance of boulders, are most likely to form blocking dams.

  16. Identification of debris-flow hazards in warm deserts through analyzing past occurrences: Case study in South Mountain, Sonoran Desert, USA

    Science.gov (United States)

    Dorn, Ronald I.

    2016-11-01

    After recognition that debris flows co-occur with human activities, the next step in a hazards analysis involves estimating debris-flow probability. Prior research published in this journal in 2010 used varnish microlamination (VML) dating to determine a minimum occurrence of 5 flows per century over the last 8100 years in a small mountain range of South Mountain adjacent to neighborhoods of Phoenix, Arizona. This analysis led to the conclusion that debris flows originating in small mountain ranges in arid regions like the Sonoran Desert could pose a hazard. Two major precipitation events in the summer of 2014 generated 35 debris flows in the same study area of South Mountain-providing support for the importance of probability analysis as a key step in a hazards analysis in warm desert settings. Two distinct mechanisms generated the 2014 debris flows: intense precipitation on steep slopes in the first storm; and a firehose effect whereby runoff from the second storm was funneled rapidly by cleaned-out debris-flow chutes to remobilize Pleistocene debris-flow deposits. When compared to a global database on debris flows, the 2014 storms were among the most intense to generate desert debris flows - indicating that storms of lesser intensity are capable of generating debris flows in warm desert settings. The 87Sr/86Sr analyses of fines and clasts in South Mountain debris flows of different ages reveal that desert dust supplies the fines. Thus, wetter climatic periods of intense rock decay are not needed to resupply desert slopes with fines; instead, a combination of dust deposition supplying fines and dirt cracking generating coarse clasts can re-arm chutes in a warm desert setting with abundant dust.

  17. Internal characteristics of refractive-index matched debris flows

    Science.gov (United States)

    Gollin, Devis; Bowman, Elisabeth; Sanvitale, Nicoletta

    2016-04-01

    Debris flows are channelized masses of granular material saturated with water that travel at high speeds downslope. Their destructive character represents a hazard to lives and properties, especially in regions of high relief and runoff. The characteristics that distinguish their heterogeneous, multi-phase, nature are numerous: non-uniform surge formation, particle size ranging from clay to boulders, flow segregation with larger particles concentrating at the flow front and fluid at the tail making the composition and volume of the bulk varying with time and space. These aspects render these events very difficult to characterise and predict, in particular in the area of the deposit spread or runout - zones which are generally of most interest in terms of human risk. At present, considerable gaps exist in our understanding of the flow dynamics of debris flows, which originates from their complex motion and relatively poor observations available. Flume studies offer the potential to examine in detail the behaviour of model debris flows, however, the opaque nature of these flows is a major obstacle in gaining insight of their internal behaviour. Measurements taken at the sidewalls may be poorly representative leading to incomplete or misleading results. To probe internally to the bulk of the flow, alternative, nonintrusive techniques can be used, enabling, for instance, velocities and solid concentrations within the flowing material to be determined. We present experimental investigations into polydisperse granular flows of spherical immersed particles down an inclined flume, with specific attention directed to their internal behavior. To this end, the refractive indices of solids and liquid are closely matched allowing the two phases to be distinguished. Measurements are then made internally at a point in the channel via Plane Laser Induced Fluorescence, Particle Tracking Velocimetry, PTV and Particle Image Velocimetry, PIV. The objective is to to increase our

  18. Enabling Large-body Active Debris Removal Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Research suggests that: (1) orbital debris has reached the point that, even with no future launches, collisions among large-body debris will lead to unstable growth...

  19. Enabling Large-body Active Debris Removal Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Research suggests that: (1) orbital debris has reached an unstable point whereby, even with no future launches, the amount of debris will continue to grow through...

  20. Post-Main Sequence Evolution of Debris Discs

    OpenAIRE

    Bonsor, Amy; Wyatt, Mark

    2010-01-01

    The population of debris discs on the main sequence is well constrained, however very little is known about debris discs around evolved stars. In this work we provide a theoretical framework that considers the effects of stellar evolution on debris discs; firstly considering the evolution of an individual disc from the main sequence through to the white dwarf phase, then extending this to the known population of debris discs around main sequence A stars. It is found that discs around evolved ...

  1. Influence of fine sediment on the fluidity of debris flows

    OpenAIRE

    HOTTA, Norifumi; Kaneko, Takahiro; Iwata, Tomoyuki; Nishimoto, Haruo

    2013-01-01

    Debris flows include a great diversity of grain sizes with inherent features such as inverse grading, particle size segregation, and liquefaction of fine sediment. The liquefaction of fine sediment affects the fluidity of debris flows, although the behavior and influence of fine sediment in debris flows have not been examined sufficiently. This study used flume tests to detect the effect of fine sediment on the fluidity of laboratory debris flows consisting of particles with various diameters...

  2. Debris flow relationships in the Central Spanish Pyrenees

    OpenAIRE

    Beguería, S.; A. Lorente; Garcia-Ruiz, J. M.

    2007-01-01

    Debris flows represent the most active geomorphic risk in mountainous areas, affecting infrastructures, human settlements and touristic resorts (Takahashi et al., 1981). For this reason, much effort has been put in assessing where debris flows occur and ranking the factors that trigger them, but also in defining two essential parameters in establishing debris flow hazards: what is the distance travelled by debris flows (especially the runout distance), and what is the volume of material carri...

  3. Identification of mechanisms for landslide type initiation of debris flows

    OpenAIRE

    Klubertanz, Georg; Laloui, Lyesse; Vulliet, Laurent

    2009-01-01

    The modelling of debris flow initiation in slopes is addressed in this paper. First, possible factors governing debris flow initiation are established. Then, a coupled hydro-mechanical model for deformable porous media with two pore fluids that is used to assess the problem of the debris flow initiation in slopes is briefly outlined. Various ways to identify failure and to approach the transition of the failed mass into a debris flow are discussed in the framework of small strain theory and e...

  4. Interpreting the extended emission around three nearby debris disc host stars

    Science.gov (United States)

    Marshall, J. P.; Kirchschlager, F.; Ertel, S.; Augereau, J.-C.; Kennedy, G. M.; Booth, M.; Wolf, S.; Montesinos, B.; Eiroa, C.; Matthews, B.

    2014-10-01

    Context. Cool debris discs are a relic of the planetesimal formation process around their host star, analogous to the solar system's Edgeworth-Kuiper belt. As such, they can be used as a proxy to probe the origin and formation of planetary systems like our own. Aims: The Herschel open time key programmes "DUst around NEarby Stars" (DUNES) and "Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre" (DEBRIS) observed many nearby, sun-like stars at far-infrared wavelengths seeking to detect and characterize the emission from their circumstellar dust. Excess emission attributable to the presence of dust was identified from around ~20% of stars. Herschel's high angular resolution (~7'' FWHM at 100 μm) provided the capacity for resolving debris belts around nearby stars with radial extents comparable to the solar system (50-100 au). Methods: As part of the DUNES and DEBRIS surveys, we obtained observations of three debris disc stars, HIP 22263 (HD 30495), HIP 62207 (HD 110897), and HIP 72848 (HD 131511), at far-infrared wavelengths with the Herschel PACS instrument. Combining these new images and photometry with ancilliary data from the literature, we undertook simultaneous multi-wavelength modelling of the discs' radial profiles and spectral energy distributions using three different methodologies: single annulus, modified black body, and a radiative transfer code. Results: We present the first far-infrared spatially resolved images of these discs and new single-component debris disc models. We characterize the capacity of the models to reproduce the disc parameters based on marginally resolved emission through analysis of two sets of simulated systems (based on the HIP 22263 and HIP 62207 data) with the noise levels typical of the Herschel images. We find that the input parameter values are recovered well at noise levels attained in the observations presented here.

  5. A novel signal processing approach for LEO space debris based on a fence-type space surveillance radar system

    Science.gov (United States)

    Huang, Jian; Hu, Weidong; Ghogho, Mounir; Xin, Qin; Du, Xiaoyong; Guo, Weiwei

    2012-12-01

    The increase in space debris can seriously threaten regular activities in the Low Earth Orbit (LEO) environment. Therefore, it is necessary to develop robust, efficient and reliable techniques to understand the potential motions of the LEO debris. In this paper, we propose a novel signal processing approach to detect and estimate the motions of LEO space debris that is based on a fence-type space surveillance radar system. Because of the sparse distribution of the orbiting debris through the fence in our observations, we formulate the signal detection and the motion parameter estimation as a sparse signal reconstruction problem with respect to an over-complete dictionary. Moreover, we propose a new scheme to reduce the size of the original over-complete dictionary without the loss of the important information. This new scheme is based on a careful analysis of the relations between the acceleration and the directions of arrival for the corresponding LEO space debris. Our simulation results show that the proposed approach can achieve extremely good performance in terms of the accuracy for detection and estimation. Furthermore, our simulation results demonstrate the robustness of the approach in scenarios with a low Signal-to-Noise Ratio (SNR) and the super-resolution properties. We hope our signal processing approach can stimulate further work on monitoring LEO space debris.

  6. Review of gas and dust in debris discs

    Science.gov (United States)

    Kral, Q.

    2016-12-01

    This proceeding summarises a talk given on the state-of-the-art of debris disc modelling. We first review the basics of debris disc physics, which is followed by a short overview of the state-of-the-art in terms of modelling dust and gas in debris disc systems.

  7. Review of gas and dust in debris discs

    OpenAIRE

    Kral, Quentin

    2016-01-01

    This proceeding summarises a talk given on the state-of-the-art of debris disc modelling. We first review the basics of debris disc physics, which is followed by a short overview of the state-of-the-art in terms of modelling dust and gas in debris disc systems.

  8. Space Debris Research Activities In China In 2007

    Institute of Scientific and Technical Information of China (English)

    Li Ming

    2008-01-01

    @@ The year 2007 was important for us to carry out the Eleventh Five-Year Space Debris Research Action Plan. Through the unremitting efforts of all space debris project research groups, we completed the space debris research projects in 2007 successfully, among which we made the substantive progress in many projects, which has laid a good foundation for the continuous research in the future.

  9. Uncertainties in Predicting Debris Flow Hazards Following Wildfire

    NARCIS (Netherlands)

    Hyde, K.D.; Riley, Karin; Stoof, C.R.

    2016-01-01

    Wildfire increases the probability of debris flows posing hazardous conditions where values-at-risk exist downstream of burned areas. Conditions and processes leading to postfire debris flows usually follow a general sequence defined here as the postfire debris flow hazard cascade: biophysical setti

  10. Monitoring the abundance of plastic debris in the marine environment

    NARCIS (Netherlands)

    Ryan, P.G.; Moore, C.J. C.J.; Franeker, van J.A.; Moloney, C.L.

    2009-01-01

    Plastic debris has significant environmental and economic impacts in marine systems. Monitoring is crucial to assess the efficacy of measures implemented to reduce the abundance of plastic debris, but it is complicated by large spatial and temporal heterogeneity in the amounts of plastic debris and

  11. Review of gas and dust in debris discs

    CERN Document Server

    Kral, Quentin

    2016-01-01

    This proceeding summarises a talk given on the state-of-the-art of debris disc modelling. We first review the basics of debris disc physics, which is followed by a short overview of the state-of-the-art in terms of modelling dust and gas in debris disc systems.

  12. Provision, transport and deposition of debris in urban waterways

    Institute of Scientific and Technical Information of China (English)

    Deonie Allen; Scott Arthur; Nicolas Wallerstien; Janice Blanc; Heather Haynes

    2015-01-01

    abstract The transport of woody debris from urban surfaces, through local urban waterways, to constriction and blockage risk locations is not well understood. Flume trials have identified debris and water-course dimensions as influential factors on debris movement, and large woody debris movement has been traced in the natural rural environment using time series photography, active transponders, and field surveys. Using novel passive transponder technology, small woody debris has been traced through an urban case study watercourse to establish key influential factors on urban debris transport. Through incorporating urban debris transport detail into the source and deposition process, a complete picture of urban debris transport can be created, supporting effective culvert and trash screen design, watercourse maintenance and blockage risk assessment. This case study highlights that factors beyond watercourse depth and velocity are influential in debris movement within an urban watercourse. Debris dimension and source location upstream are shown to significantly affect the potential for debris to reach a downstream constriction, illustrating a possible distance limitation in nuisance flow debris blockage risk.

  13. On the Solar System-Debris Disk Connecction

    OpenAIRE

    Moro-Martin, Amaya

    2007-01-01

    This paper emphasizes the connection between solar and extra-solar debris disks: how models and observations of the Solar System are helping us understand the debris disk phenomenon, and vice versa, how debris disks are helping us place our Solar System into context.

  14. Europium-155 in Debris from Nuclear Weapons

    DEFF Research Database (Denmark)

    Aarkrog, Asker; Lippert, Jørgen Emil

    1967-01-01

    The lithium-drifted germanium detector enables determination of europium-155 on a routine basis in environmental samples contaminated with debris from nuclear weapons. From measurements of europium-155, cesium-144, and strontium-90 in air filters collected between 1961 and 1966, the yield...

  15. Spacecraft Robustness to Orbital Debris: Guidelines & Recommendations

    Science.gov (United States)

    Heinrich, S.; Legloire, D.; Tromba, A.; Tholot, M.; Nold, O.

    2013-09-01

    The ever increasing number of orbital debris has already led the space community to implement guidelines and requirements for "cleaner" and "safer" space operations as non-debris generating missions and end of mission disposal in order to get preserved orbits rid of space junks. It is nowadays well-known that man-made orbital debris impacts are now a higher threat than natural micro-meteoroids and that recent events intentionally or accidentally generated so many new debris that may initiate a cascade chain effect known as "the Kessler Syndrome" potentially jeopardizing the useful orbits.The main recommendations on satellite design is to demonstrate an acceptable Probability of Non-Penetration (PNP) with regard to small population (risks with the introduction of new of probability and criticality classification scales. * Examples of design risks assessment with regard to the specific MMOD impact risks. * Lessons learnt on robustness survivability of systems (materials, shieldings, rules) coming from other industrial domains (automotive, military vehicles) * Guidelines and Recommendations implementable on satellite systems and mechanical architecture.

  16. Numerical modeling of the debris flows runout

    Science.gov (United States)

    Federico, Francesco; Cesali, Chiara

    2017-06-01

    Rapid debris flows are identified among the most dangerous of all landslides. Due to their destructive potential, the runout length has to be predicted to define the hazardous areas and design safeguarding measures. To this purpose, a continuum model to predict the debris flows mobility is developed. It is based on the well known depth-integrated avalanche model proposed by Savage and Hutter (S&H model) to simulate the dry granular materials flows. Conservation of mass and momentum equations, describing the evolving geometry and the depth averaged velocity distribution, are re-written taking into account the effects of the interstitial pressures and the possible variation of mass along the motion due to erosion/deposition processes. Furthermore, the mechanical behaviour of the debris flow is described by a recently developed rheological law, which allows to take into account the dissipative effects of the grain inelastic collisions and friction, simultaneously acting within a `shear layer', typically at the base of the debris flows. The governing PDEs are solved by applying the finite difference method. The analysis of a documented case is finally carried out.

  17. Molecular gas in young debris disks

    CERN Document Server

    Moór, A; Juhász, A; Kiss, Cs; Pascucci, I; Kóspál, Á; Apai, D; Henning, Th; Csengeri, T; Grady, C

    2011-01-01

    Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. Interestingly, the debris disk around the young main-sequence star 49 Ceti possesses a substantial amount of molecular gas, and possibly represents the missing link between the two phases. Motivated to understand the evolution of the gas component in circumstellar disks via finding more 49 Ceti-like systems, we carried out a CO J=3-2 survey with Atacama Pathfinder EXperiment, targeting 20 infrared-luminous debris disks. These systems fill the gap between primordial and old tenuous debris disks in terms of fractional luminosity. Here we report on the discovery of a second 49 Ceti-like disk around the 30 Myr old A3-type star HD21997, a member of the Columba Association. This system was also detected in the CO(2-1) transition, and the reliable age determination makes it an even clearer example of an old gas-bearing disk than 49 Ceti. While the fractional luminosities...

  18. Orbiting Space Debris: Dangers, Measurement and Mitigation

    Science.gov (United States)

    1992-06-01

    sure how many undetectable particles the fragmentation of a satellite creates. Actual ground-based tesis have been conducted in an attempt to...conducted by the Jet Propulsion Laboratory lo measure the presence of 0.2 lo 0.5 cm and 0.5 to 2 cm sized debris. The Areclbo radar in Puerto Rico

  19. Feasibility of using {sup 236}U to reconstruct close-in fallout deposition from the Hiroshima atomic bomb

    Energy Technology Data Exchange (ETDEWEB)

    Sakaguchi, A., E-mail: ayaskgc@hiroshima-u.ac.jp [Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526 (Japan); Kawai, K. [Low Level Radioactivity Laboratory, K-INET, Kanazawa University, Nomi, Ishikawa 923-1224 (Japan); Steier, P. [VERA-Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Str. 17, 1090 Vienna (Austria); Imanaka, T. [Research Reactor Institute, Kyoto University, Kumatori-cho, Osaka 590-0494 (Japan); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Endo, S. [Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527 (Japan); Zhumadilov, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Yamamoto, M. [Low Level Radioactivity Laboratory, K-INET, Kanazawa University, Nomi, Ishikawa 923-1224 (Japan)

    2010-10-15

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

  20. Dating of a sediment core from Lake Biel (Switzerland) and source characterization of fallout Pu; {sup 210}Pb- und {sup 137}Cs-Datierung eines Sedimentbohrkerns aus dem Bieler See (CH) und Ursprungsbestimmung von Pu-Fallout

    Energy Technology Data Exchange (ETDEWEB)

    Pregler, Anja

    2016-08-01

    A sediment core from Lake Biel was dated by means of the naturally occurring radioactive isotope {sup 210}Pb as well as by the anthropogenic isotope {sup 137}Cs. The latter one can be detected as radioactive fallout of certain events in the sediment layers and accordingly be correlated with a distinct date. A verification of the correlated events is accomplished by particular isotope ratios of the anthropogenic isotopes {sup 238}Pu, {sup 239}Pu and {sup 240}Pu as well as {sup 241}Am as a decay product of the short-lived {sup 241}Pu. Furthermore, the percentage of the total {sup 137}Cs fallout was calculated corresponding to the specific events.

  1. Debris measure subsystem of the nanosatellite IRECIN

    Science.gov (United States)

    Ferrante, M.; di Ciolo, L.; Ortenzi, A.; Petrozzi, M.; del Re, V.

    2003-09-01

    The on board resources, needed to perform the mission tasks, are very limited in nano-satellites. This paper proposes an Electronic real-time system that acquires space debris measures. It uses a piezo-electric sensor. The described device is a subsystem on board of the IRECIN nanosatellite composed mainly by a r.i.s.c. microprocessor, an electronic part that interfaces to the debris sensor in order to provide a low noise electrical and suitable range to ADC 12 bit converter, and finally a memory in order to store the data. The microprocessor handles the Debris Measure System measuring the impacts number, their intensity and storing their waves form. This subsystem is able to communicate with the other IRECIN subsystems through I2C Bus and principally with the "Main Microprocessor" subsystem allowing the data download directly to the Ground Station. Moreover this subsystem lets free the "Main Microprocessor Board" from the management and charge of debris data. All electronic components are SMD technology in order to reduce weight and size. The realized Electronic board are completely developed, realized and tested at the Vitrociset S.P.A. under control of Research and Development Group. The proposed system is implemented on the IRECIN, a modular nanosatellite weighting less than 1.5 kg, constituted by sixteen external sides with surface-mounted solar cells and three internal Al plates, kept together by four steel bars. Lithium-ions batteries are added for eclipse operations. Attitude is determined by two three-axis magnetometers and the solar panels data. Control is provided by an active magnetic control system. The spacecraft will be spin-stabilized with the spin-axis normal to the orbit. debris and micrometeoroids mass and velocity.

  2. Brief communication: Thinning of debris-covered and debris-free glaciers in a warming climate

    Science.gov (United States)

    Banerjee, Argha

    2017-01-01

    Recent geodetic mass-balance measurements reveal similar thinning rates on glaciers with or without debris cover in the Himalaya-Karakoram region. This comes as a surprise as a thick debris cover reduces the surface melting significantly due to its insulating effects. Here we present arguments, supported by results from numerical flowline model simulations of idealised glaciers, that a competition between the changes in the surface mass-balance forcing and that of the emergence/submergence velocities can lead to similar thinning rates on these two types of glaciers. As the climate starts warming, the thinning rate on a debris-covered glacier is initially smaller than that on a similar debris-free glacier. Subsequently, the rate on the debris-covered glacier becomes comparable to and then larger than that on the debris-free one. The time evolution of glacier-averaged thinning rates after an initial warming is strongly controlled by the time variation of the corresponding emergence velocity profile.

  3. The Debris Disk Explorer: a balloon-borne coronagraph for observing debris disks

    CERN Document Server

    Roberts, Lewis C; Traub, Wesley; Unwin, Stephen; Trauger, John; Krist, John; Aldrich, Jack; Brugarolas, Paul; Stapelfeldt, Karl; Wyatt, Mark; Stuchlik, David; Lanzi, James

    2013-01-01

    The Debris Disk Explorer (DDX) is a proposed balloon-borne investigation of debris disks around nearby stars. Debris disks are analogs of the Asteroid Belt (mainly rocky) and Kuiper Belt (mainly icy) in our Solar System. DDX will measure the size, shape, brightness, and color of tens of disks. These measurements will enable us to place the Solar System in context. By imaging debris disks around nearby stars, DDX will reveal the presence of perturbing planets via their influence on disk structure, and explore the physics and history of debris disks by characterizing the size and composition of disk dust. The DDX instrument is a 0.75-m diameter off-axis telescope and a coronagraph carried by a stratospheric balloon. DDX will take high-resolution, multi-wavelength images of the debris disks around tens of nearby stars. Two flights are planned; an overnight test flight within the United States followed by a month-long science flight launched from New Zealand. The long flight will fully explore the set of known de...

  4. Debris thickness and surface topography on Ngozumpa Glacier, Nepal

    Science.gov (United States)

    McCarthy, Michael; Nicholson, Lindsey; Rieg, Lorenzo; Klug, Christoph; Wirbel, Anna; Del Gobbo, Costanza; Pritchard, Hamish; Willis, Ian; Mayer, Christoph

    2017-04-01

    The ablation zones of many Himalayan glaciers are partially to completely covered with a layer of rock debris, the thickness of which is a key control on surface melt rates. Although it is commonly assumed that supraglacial debris is redistributed by gravitational processes due to variable surface topography, the nature of such a relationship has not been fully explored. Here we present locally extensive debris thickness data collected on Ngozumpa Glacier, Nepal, using ground-penetrating radar (GPR), and investigate, by comparison with a high-resolution digital terrain model (DTM), the relationship between debris thickness and surface topography. We compare debris thickness with slope, aspect, and hillslope curvature and look at how debris thickness relates to features of interest on the glacier surface. The existence of a relationship between debris thickness and surface topography has potentially important implications for remote sensing estimates of debris thickness made using thermal band satellite imagery because DTMs are commonly available at relatively high spatial resolution. For this reason, we assess whether or not debris thickness and surface topography covary. Further, due to the typically non-linear relationship between debris thickness and surface temperature, remote sensing estimates of debris thickness are affected by sub-pixel scale debris thickness variability. To see how debris thickness varies at sub-pixel scale, and the extent to which such variability should affect remote sensing-derived debris thickness estimates, we explore the effects of resampling our debris thickness data to the resolution of the thermal bands of ASTER and Landsat satellite images.

  5. Anthropogenic Debris Ingestion by Avifauna in Eastern Australia.

    Science.gov (United States)

    Roman, Lauren; Schuyler, Qamar A; Hardesty, Britta Denise; Townsend, Kathy A

    2016-01-01

    Anthropogenic debris in the world's oceans and coastal environments is a pervasive global issue that has both direct and indirect impacts on avifauna. The number of bird species affected, the feeding ecologies associated with an increased risk of debris ingestion, and selectivity of ingested debris have yet to be investigated in most of Australia's coastal and marine birds. With this study we aim to address the paucity of data regarding marine debris ingestion in Australian coastal and marine bird species. We investigated which Australian bird groups ingest marine debris, and whether debris-ingesting groups exhibit selectivity associated with their taxonomy, habitat or foraging methods. Here we present the largest multispecies study of anthropogenic debris ingestion in Australasian avifauna to date. We necropsied and investigated the gastrointestinal contents of 378 birds across 61 species, collected dead across eastern Australia. These species represented nine taxonomic orders, five habitat groups and six feeding strategies. Among investigated species, thirty percent had ingested debris, though ingestion did not occur uniformly within the orders of birds surveyed. Debris ingestion was found to occur in orders Procellariiformes, Suliformes, Charadriiformes and Pelecaniformes, across all surveyed habitats, and among birds that foraged by surface feeding, pursuit diving and search-by-sight. Procellariiformes, birds in pelagic habitats, and surface feeding marine birds ingested debris with the greatest frequency. Among birds which were found to ingest marine debris, we investigated debris selectivity and found that marine birds were selective with respect to both type and colour of debris. Selectivity for type and colour of debris significantly correlated with taxonomic order, habitat and foraging strategy. This study highlights the significant impact of feeding ecology on debris ingestion among Australia's avifauna.

  6. Renewal of explosive activity at Vesuvius: models for the expected tephra fallout

    Science.gov (United States)

    Macedonio, Giovanni; Pareschi, M. Teresa; Santacroce, Roberto

    1990-06-01

    One of the major problems concerning the assessment of volcanic hazard at Vesuvius is to determine the type and size of the eruptive event that will characterize the volcano when it becomes active once again. During its history, Somma-Vesuvius has exhibited different types of activity, ranging from quiet lava emission to moderate strombolian activity, to catastrophic plinian eruptions. Available data support a behavior model characterized by the increasing size and explosiveness of the eruptions with increasing repose time, as a consequence of a roughly constant periodic supply of deep basic magma to a shallow magma chamber and differentiation and mixing in the chamber. After the A.D. 79 eruption, a homogeneous HK (high potassium) nature of erupted products was reflected by a magma alimentation rate roughly estimated at 1.5-2.0 millions of cubic meters per year. Assuming no major changes have occurred in the feeding system of the volcano after its last eruption in 1944, a volume of 40-70 × 10 6 m 3 magma could be considered presently available for a renewal of activity at Vesuvius. The emission of such a mass of magma during a single eruption would result into the largest event since the highly disruptive 1631 subplinian eruption. Presently, no possibility exists to forecast the eruptive character of such an eruption, and either a "ultrastrombolian" or a "subplinian" case appear equally possible. The latter possibility implies the highest potential hazard. This paper provides the numerical simulations of the main eruptive phenomenon that probably will occur during this "maximum expected event": the fallout of tephra from a high, sustained eruption column. After the initial explosive opening of the vent, the scenario consists of the formation of a high convective column with lee-side fallout of pumice and lithic fragments, accompanied and followed by column collapses generating pyroclastic flows and surges. The column behavior was numerically simulated by using the

  7. Reading the Signatures of Extrasolar Planets in Debris Disks

    Science.gov (United States)

    Kuchner, Marc J.

    2009-01-01

    An extrasolar planet sculpts the famous debris dish around Fomalhaut; probably ma ny other debris disks contain planets that we could locate if only we could better recognize their signatures in the dust that surrounds them. But the interaction between planets and debris disks involves both orbital resonances and collisions among grains and rocks in the disks --- difficult processes to model simultanemus]y. I will describe new 3-D models of debris disk dynamics that incorporate both collisions and resonant trapping of dust for the first time, allowing us to decode debris disk images and read the signatures of the planets they contain.

  8. Behavior and food consumption pattern of the population exposed in 1949-1962 to fallout from Semipalatinsk nuclear test site in Kazakhstan.

    Science.gov (United States)

    Drozdovitch, Vladimir; Schonfeld, Sara; Akimzhanov, Kuat; Aldyngurov, Daulet; Land, Charles E; Luckyanov, Nickolas; Mabuchi, Kiyohiko; Potischman, Nancy; Schwerin, Michael J; Semenova, Yulia; Tokaeva, Alma; Zhumadilov, Zhaxybay; Bouville, André; Simon, Steven L

    2011-03-01

    The relationship between radiation exposure from nuclear weapons testing fallout and thyroid disease in a group of 2,994 subjects has been the subject of study by the US National Cancer Institute. In that study, radiation doses to the thyroid were estimated for residents of villages in Kazakhstan possibly exposed to deposition of radioactive fallout from nuclear testing conducted by the Soviet Union at the Semipalatinsk Nuclear Test Site in Kazakhstan between 1949 and 1962. The study subjects included individuals of both Kazakh and Russian origin who were exposed during childhood and adolescence. An initial dose reconstruction used for the risk analysis of Land et al. (Radiat Res 169:373-383, 2008) was based on individual information collected from basic questionnaires administered to the study population in 1998. However, because data on several key questions for accurately estimating doses were not obtained from the 1998 questionnaires, it was decided to conduct a second data collection campaign in 2007. Due to the many years elapsed since exposure, a well-developed strategy was necessary to encourage accurate memory recall. In our recent study, a focus group interview data collection methodology was used to collect historical behavioral and food consumption data. The data collection in 2007 involved interviews conducted within four-eight-person focus groups (three groups of women and one group of men) in each of four exposed villages where thyroid disease screening was conducted in 1998. Population-based data on relevant childhood behaviors including time spent in- and outdoors and consumption rates of milk and other dairy products were collected from women's groups. The data were collected for five age groups of children and adolescents ranging from less than 1 year of age to 21 years of age. Dairy products considered included fresh milk and other products from cows, goats, mares, and sheep. Men's focus group interviews pertained to construction materials of

  9. Erosion and sediment deposition evaluation on a slope under pasture in Jandaia-GO using the '{sup 137}Cs fallout' technique

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Robson C.J.; Bacchi, Osny O.S.; Reichardt, Klaus, E-mail: rcarthur@cena.usp.b, E-mail: osny@cena.usp.b, E-mail: klaus@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Oliveira, Carloeme Alves de; Correchel, Vladia, E-mail: vladia@agro.ufg.b, E-mail: carloemeoliveira@hotmail.co [Universidade Federal de Goias (UFG), Goiania, GO (Brazil)

    2009-07-01

    Water erosion is one of the main forms of soil degradation and among the diverse factors that affect it, two of great importance are the soil cover and slope. Estimates of sediment distribution rates associated to the different uses and soil management practices are scarce and the employed methods in these determinations are in general costly and time consuming. Rates of sediment redistribution evaluated by means of the {sup 137}Cs technique are based on the comparison of inventories of individual points of a given position and an inventory of reference, whose value represents the amount of {sup 137}Cs of 'fallout' origin that was added to the local site. This allows evaluating situations of losses and accumulations of sediments by the erosive process. The objective of the present work was to analyze the sediment production in a pasture area and to measure the efficiency of riparian forests in trapping the erosion sediments coming from pasture, through the '{sup 137}Cs fallout' redistribution analysis. The study was carried out in Jandaia/GO, Brazil, in two dowslope transects located in a pasture area. Samples were taken from seven points of two 140 m long transects, as well as from three soil profiles of a 15 m transect in the downstream riparian forests of each transect. Soil profiles were sampled in three layers of 20 cm (0-20, 20-40 and 40-60). The soil samples were air dried, sieved and then analyzed for {sup 137}Cs activity by a gamma ray detector (GEM-20180P, EG and ORTEC) coupled to a multichannel analyzer at CENA/USP. The results indicate variations of {sup 137}Cs activity in soil profiles and high erosion rates to the riparian forest to the pasture areas of the two transects, showing sediment movement from the pasture area to the riparian forest, which suggests that the current width of the forest is not wide enough to trap the sediments produced upslope in the pasture area. (author)

  10. Quantifying volume loss from ice cliffs on debris-covered glaciers using high-resolution terrestrial and aerial photogrammetry

    NARCIS (Netherlands)

    Brun, Fanny; Buri, Pascal; Miles, Evan S.; Wagnon, Patrick; Steiner, J.F.|info:eu-repo/dai/nl/119338653; Berthier, Etienne; Ragettli, S.; Kraaijenbrink, P.D.A.; Immerzeel, W.W.|info:eu-repo/dai/nl/290472113; Pellicciotti, Francesca

    Mass losses originating from supraglacial ice cliffs at the lower tongues of debris-covered glaciers are a potentially large component of the mass balance, but have rarely been quantified. In this study, we develop a method to estimate ice cliff volume losses based on high-resolution topographic

  11. Emplacement of a Debris Ocean on Mars by Regional-Scale Collapse and Flow at the Crustal Dichotomy

    Science.gov (United States)

    Hoffman, N.; Tanaka, K. L.; Kargel, J. S.; Banerdt, W. B.

    2001-01-01

    Giant debris flows could have filled the northern lowlands with approx. 2 km of sediment in 10(exp 3) to 10(exp 5) years by catastrophic regional terrain collapse. The outburst floods and chaos zones are probably the waning stage of this process. Additional information is contained in the original extended abstract.

  12. The new conversion model MODERN to derive erosion rates from inventories of fallout radionuclides

    Science.gov (United States)

    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

  13. Space Transportation System Liftoff Debris Mitigation Process Overview

    Science.gov (United States)

    Mitchell, Michael; Riley, Christopher

    2011-01-01

    Liftoff debris is a top risk to the Space Shuttle Vehicle. To manage the Liftoff debris risk, the Space Shuttle Program created a team with in the Propulsion Systems Engineering & Integration Office. The Shutt le Liftoff Debris Team harnesses the Systems Engineering process to i dentify, assess, mitigate, and communicate the Liftoff debris risk. T he Liftoff Debris Team leverages off the technical knowledge and expe rtise of engineering groups across multiple NASA centers to integrate total system solutions. These solutions connect the hardware and ana lyses to identify and characterize debris sources and zones contribut ing to the Liftoff debris risk. The solutions incorporate analyses sp anning: the definition and modeling of natural and induced environmen ts; material characterizations; statistical trending analyses, imager y based trajectory analyses; debris transport analyses, and risk asse ssments. The verification and validation of these analyses are bound by conservative assumptions and anchored by testing and flight data. The Liftoff debris risk mitigation is managed through vigilant collab orative work between the Liftoff Debris Team and Launch Pad Operation s personnel and through the management of requirements, interfaces, r isk documentation, configurations, and technical data. Furthermore, o n day of launch, decision analysis is used to apply the wealth of ana lyses to case specific identified risks. This presentation describes how the Liftoff Debris Team applies Systems Engineering in their proce sses to mitigate risk and improve the safety of the Space Shuttle Veh icle.

  14. Triggering Mechanism and characteristic of Debris Flow in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Norhidayu Kasim

    2016-04-01

    Full Text Available Forensic investigations have been carried out at eight (8 selected debris flow locations in Peninsular Malaysia in order to determine the mechanism and characteristic of debris flow. Comprehensive studies on the available records of past debris flow have been carried out in order to describe the fundamental characteristics of debris flow events. Site investigation and laboratory tests of particular debris flow sites were carried out to evaluate the causes of the debris flow triggering factors such as topographical, geotechnical and geological characteristics. Rainfall records are collected from the nearest meteorological station in order to analyse the reasonable correlation of rainfall with the occurrence of debris flow. Geological study shows that debris flow is prone to occur at granitic areas. The gradient of the initiation areas are above 20 and the debris tends to deposit in the areas with gradient between 2 to 15. Laboratory tests show that the soil type at the debris flow areas consists predominantly of silty sand classified as SM according to the Unified Soil Classification System. The relation between rainfall patterns and the possible occurrences of debris flow indicated that the trigger thresholds are found to be generally high in most cases

  15. Prevention of debris flow disasters on Chengdu-Kunming Railway

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chengdu-Kunming Railway is an important transport line on southwestern China. However, this railway's safety is often threatened by debris flows. How to effectively forecast and alarm the debris flow disasters and reduce the losses is the aim to study the prevention system in this paper. The factors to cause or influence debris flow are divided into four parts——the basin environmental factors, the basin meteoric factors, the prevention work's elements and the flood-relief work's elements, and the prevention system is made up of three models——a judgment model to assess the debris flow gully's seriousness, a forecast model to predict the debris flow's occurrence and an alarm model to evaluate the debris flow's disaster. Afterwards, a concise structure chart is worked out and verified by the field data from Chengdu-Kunming Railway. This prevention system will provide beneficial reference for the debris flow's monitoring network to be executed on Chengdu-Kunming Railway.

  16. Prevention of debris flow disasters on Chengdu-Kunming Railway.

    Science.gov (United States)

    Wang, W; Xu, W L; Liu, S J

    2001-07-01

    Chengdu-Kunming Railway is an important transport line on southwestern China. However, this railway's safety is often threatened by debris flows. How to effectively forecast and alarm the debris flow disasters and reduce the losses is the aim to study the prevention system in this paper. The factors to cause or influence debris flow are divided into four parts--the basin environmental factors, the basin meteoric factors, the prevention work's elements and the flood-relief work's elements, and the prevention system is made up of three models--a judgment model to assess the debris flow gully's seriousness, a forecast model to predict the debris flow's occurrence and an alarm model to evaluate the debris flow's disaster. Afterwards, a concise structure chart is worked out and verified by the field data from Chengdu-Kunming Railway. This prevention system will provide beneficial reference for the debris flow's monitoring network to be executed on Chengdu-Kunming Railway.

  17. Self-organization criticality of debris flow rheology

    Institute of Scientific and Technical Information of China (English)

    WANG Yuyi; JAN Chyandeng; CHEN Xiaoqing; HAN Wenliang

    2003-01-01

    Based on the viewpoint of stress and strain self-organization criticality of debris flow mass, this paper probes into inter-nonlinear action between different factors in the thixotropic liquefaction system of loose clastic soil onslope to make clastic soil in slope develop naturally towards critical stress status, and slope debris flow finally occurs under trigging by rainstorm. Also according to observation and analysis of self-organization criticality of sedimentrunoff system of viscous debris flow surges in ravines and power relation between magnitude and frequency of debris flows, this paper expounds similarity of the self-organized structure of debris flow mass. The self-organized critical system is a weak chaotic system. Debris flow occurrences can be predicted accordingly by means of observation at certain time scale and analysis of self-organization criticality of magnitude, frequency and time interval of debris flows.

  18. Polybrominated diphenyl ethers in air and fallouts from an e-waste polluted region in southeast China: insight into levels, compositional profiles, and seasonal variation.

    Science.gov (United States)

    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.

  19. Fallout and drinking water contamination by I-131 and Cs-134, 137 in Japan, from the Fukushima Daiichi NPS accident

    Energy Technology Data Exchange (ETDEWEB)

    Kelecom, Alphonse; Miyashita, Erika; Kelecom, Patrick Vicent [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

    2011-07-01

    The earthquake followed by a tsunami in Japan, on last March 11, seriously damaged four of the six reactors of the Fukushima Daiichi nuclear power station (NPS). Radioactive smokes and highly contaminated water were released for weeks to the environment. Since March 12, when the plant operator TEPCO and Japan's nuclear agency (NISA) confirmed the presence of radionuclides near the NPS, a giant environmental monitoring operation was set up, covering the entire Japanese territory. Daily thousands measurements are realized. We here analyze data released during 60 days on I-131 and Cs-134,137 radioactive concentrations in drinking water and fallout for 45 prefectures. Miyagi and Fukushima, that requires a separate study, are not considered here. Drinking water contamination by I-131 was observed in 13 prefectures, including Tokyo. The most impacted one was Tochigi (maximum of 110 Bq/l, March 24). This value turned water not drinkable for infants and babies. Cs-137 was detected in drinking water in 8 prefectures, with a maximum level of 18 Bq/l in Ibaraki. These levels do not affect potability of tap water. I-131 was observed in fallout in 27 prefectures, with level reaching 93 kBq/m2 in Ibaraki and 36 kBq/m{sup 2} in Tokyo on March 21 and 23 respectively. Fallout of Cs-137 was observed in 19 prefectures. The maximum deposition occurred again in Ibaraki (13kBq/m{sup 2}, March 21) and in Tokyo (5.3 kBq/m2, March 22). Since mid April, only trace contamination has been observed for both radionuclides in drinking water. Sporadically medium levels of Cs-137 are still observed in fallout. (author)

  20. Fire debris analysis for forensic fire investigation using laser induced breakdown spectroscopy (LIBS)

    Science.gov (United States)

    Choi, Soojin; Yoh, Jack J.

    2017-08-01

    The possibility verification of the first attempt to apply LIBS to arson investigation was performed. LIBS has capabilities for real time in-situ analysis and depth profiling. It can provide valuable information about the fire debris that are complementary to the classification of original sample components and combustion residues. In this study, fire debris was analyzed to determine the ignition source and existence of a fire accelerant using LIBS spectra and depth profiling analysis. Fire debris chemical composition and carbon layer thickness determines the possible ignition source while the carbon layer thickness of combusted samples represents the degree of sample carbonization. When a sample is combusted with fire accelerants, a thicker carbon layer is formed because the burning rate is increased. Therefore, depth profiling can confirm the existence of combustion accelerants, which is evidence of arson. Also investigation of fire debris by depth profiling is still possible when a fire is extinguished with water from fire hose. Such data analysis and in-situ detection of forensic signals via the LIBS may assist fire investigation at crime scenes.

  1. Lunar and Planetary Science XXXV: Mars: Wind, Dust Sand, and Debris

    Science.gov (United States)

    2004-01-01

    The session "Mars: Wind, Dust Sand, and Debris" included: Mars Exploration Rovers: Laboratory Simulations of Aeolian Interactions; Thermal and Spectral Analysis of an Intracrater Dune Field in Amazonis Planitia; How High is that Dune? A Comparison of Methods Used to Constrain the Morphometry of Aeolian Bedforms on Mars; Dust Devils on Mars: Scaling of Dust Flux Based on Laboratory Simulations; A Close Encounter with a Terrestrial Dust Devil; Interpretation of Wind Direction from Eolian Features: Herschel Crater, Mars Erosion Rates at the Viking 2 Landing Site; Mars Dust: Characterization of Particle Size and Electrostatic Charge Distributions; Simple Non-fluvial Models of Planetary Surface Modification, with Application to Mars; Comparison of Geomorphically Determined Winds with a General Circulation Model: Herschel Crater, Mars; Analysis of Martian Debris Aprons in Eastern Hellas Using THEMIS; Origin of Martian Northern Hemisphere Mid-Latitude Lobate Debris Aprons; Debris Aprons in the Tempe/Mareotis Region of Mars;and Constraining Flow Dynamics of Mass Movements on Earth and Mars.

  2. Rock-glacier dynamics and magnitude-frequency relations of debris flows in a high-elevation watershed: Ritigraben, Swiss Alps

    Science.gov (United States)

    Lugon, Ralph; Stoffel, Markus

    2010-09-01

    A widespread risk in high mountains is related to the accumulation of loose sediments on steep slopes, which represent potential sources of different types of geomorphic processes including debris flows. This paper combines data on 50 yr of permafrost creep at the Ritigraben rock glacier (Valais, Swiss Alps) with magnitude-frequency (M-F) relationships of debris flows recorded in the Ritigraben torrent originating at the rock-glacier front. Debris production and volumetric changes at the rock-glacier front are compared with debris-flow activity recorded on the cone and potential couplings and feedbacks between debris sources, channel processes and debris sinks. The dataset existing for the Ritigraben rock glacier and its debris-flow system is unique and allows prime insights into controls and dynamics of permafrost processes and related debris-flow activity in a constantly changing and warming high-altitude environment. Acceleration in rock-glacier movement rates is observed in the (1950s and) 1960s, followed by a decrease in flow rates by the 1970s, before movements increase again after the early 1990s. At a decadal scale, measured changes in rock-glacier movements at Ritigraben are in concert with changes in atmospheric temperatures in the Alps. Geodetic data indicates displacement rates in the frontal part of the rock glacier of up to 0.6-0.9 m yr -1 since the beginning of systematic measurements in 1995. While the Ritigraben rock glacier has always formed a sediment reservoir for the associated debris-flow system, annual horizontal displacement rates of the rock-glacier body have remained quite small and are in the order of decimeters under current climatic conditions. Sediment delivery from the rock-glacier front alone could not therefore be sufficient to support the 16 debris flows reconstructed on the cone since 1958. On the contrary, debris accumulated at the foot of the rock glacier, landslide and rockfall activity as well as the partial collapse of

  3. Retention of simulated fallout nuclides in agricultural crops. 2. Deposition of Cs and Sr on grain crops

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Aake; Rosen, K.; Haak, E

    1998-12-31

    Experiments with artificial wet depositions of {sup 134}Cs and {sup 85}Sr at different times during the growth period were carried out. The studies are complementary to the experiences after the Chernobyl fallout and the results are compared with similar earlier Swedish works on nuclide retention in experiments and on fallout in agriculture. The aim has been to cover the nuclide transfer to grain crops after deposition at different times during the growing period. The initial interception capacity per kg d.w., TRd, seemed to depend on the surface/weight ratio of the plant parts considered. Changes in TRd-values were rapid during the early growth but slower in later stages. The reduction half-time was then often 2 weeks for vegetative parts. Considering the fraction of a deposition retained, FRd, the residence half-time had an average length of 3-4 weeks. During that time there were possibilities for cesium penetration into the plant and further transfer to ears and grain. Strontium did not seem to be transferred that way. There was no increase of cesium in the ears per unit d.w. after the initial interception. However, there was a steady increase in the total content, especially after deposition during the latter half of the growth period when about 5 % was retained of cesium, and 2 % of strontium. The retention of fallout caesium in 1964 was statistically estimated to be of about the same size in Swedish grains 12 refs, 19 figs, 19 tabs

  4. Airborne Measurement in the Ash Plume from Mount Sakurajima: Analysis of Gravitational Effects on Dispersion and Fallout

    Directory of Open Access Journals (Sweden)

    Jonas Eliasson

    2014-01-01

    Full Text Available Volcanic ash concentrations in the plume from Sakurajima volcano in Japan are observed from airplanes equipped with optical particle counters and GPS tracking devices. The volcano emits several puffs a day. The puffs are also recorded by the Sakurajima Volcanological Observatory. High concentrations are observed in the puffs and fallout driven by vertical air current, called streak fallout. Puffs dispersion is analyzed by the classical diffusion-advection method and a new gravitational dispersion method. The fluid mechanic of the gravitational dispersion, streak fallout, and classical diffusion-advection theory is described in three separate appendices together with methods to find the time gravitational dispersion constant and the diffusion coefficient from satellite photos. The diffusion-advection equation may be used to scale volcanic eruptions so the same eruption plumes can be scaled to constant flux and wind conditions or two eruptions can be scaled to each other. The dispersion analyses show that dispersion of volcanic plumes does not follow either theories completely. It is most likely diffusion in the interface of the plume and the ambient air, together with gravitational flattening of the plumes core. This means larger boundary concentration gradients and smaller diffusion coefficients than state of the art methods can predict.

  5. Debris flow initiation in proglacial gullies on Mount Rainier, Washington

    Science.gov (United States)

    Legg, Nicholas T.; Meigs, Andrew J.; Grant, Gordon E.; Kennard, Paul

    2014-12-01

    Effects of climate change, retreating glaciers, and changing storm patterns on debris flow hazards concern managers in the Cascade Range (USA) and mountainous areas worldwide. During an intense rainstorm in November 2006, seven debris flows initiated from proglacial gullies of separate basins on the flanks of Mount Rainier. Gully heads at glacier termini and widespread failure of gully walls imply that overland flow was transformed into debris flow along gullies. We characterized gully change and morphology, and assessed spatial distributions of debris flows to infer the processes and conditions for debris flow initiation. Slopes at gully heads were greater than ~ 0.35 m m- 1 (19°) and exhibited a significant negative relationship with drainage area. A break in slope-drainage area trends among debris flow gullies also occurs at ~ 0.35 m m- 1, representing a possible transition to fluvial sediment transport and erosion. An interpreted hybrid model of debris flow initiation involves bed failure near gully heads followed by sediment recruitment from gully walls along gully lengths. Estimates of sediment volume loss from gully walls demonstrate the importance of sediment inputs along gullies for increasing debris flow volumes. Basin comparisons revealed significantly steeper drainage networks and higher elevations in debris flow-producing than non-debris flow-producing proglacial areas. The high slopes and elevations of debris flow-producing proglacial areas reflect positive slope-elevation trends for the Mount Rainier volcano. Glacier extent therefore controls the slope distribution in proglacial areas, and thus potential for debris flow generation. As a result, debris flow activity may increase as glacier termini retreat onto slopes inclined at angles above debris flow initiation thresholds.

  6. RemoveDEBRIS: An in-orbit active debris removal demonstration mission

    Science.gov (United States)

    Forshaw, Jason L.; Aglietti, Guglielmo S.; Navarathinam, Nimal; Kadhem, Haval; Salmon, Thierry; Pisseloup, Aurélien; Joffre, Eric; Chabot, Thomas; Retat, Ingo; Axthelm, Robert; Barraclough, Simon; Ratcliffe, Andrew; Bernal, Cesar; Chaumette, François; Pollini, Alexandre; Steyn, Willem H.

    2016-10-01

    Since the beginning of the space era, a significant amount of debris has progressively been generated. Most of the objects launched into space are still orbiting the Earth and today these objects represent a threat as the presence of space debris incurs risk of collision and damage to operational satellites. A credible solution has emerged over the recent years: actively removing debris objects by capturing them and disposing of them. This paper provides an update to the mission baseline and concept of operations of the EC FP7 RemoveDEBRIS mission drawing on the expertise of some of Europe's most prominent space institutions in order to demonstrate key active debris remove (ADR) technologies in a low-cost ambitious manner. The mission will consist of a microsatellite platform (chaser) that ejects 2 CubeSats (targets). These targets will assist with a range of strategically important ADR technology demonstrations including net capture, harpoon capture and vision-based navigation using a standard camera and LiDAR. The chaser will also host a drag sail for orbital lifetime reduction. The mission baseline has been revised to take into account feedback from international and national space policy providers in terms of risk and compliance and a suitable launch option is selected. A launch in 2017 is targeted. The RemoveDEBRIS mission aims to be one of the world's first in-orbit demonstrations of key technologies for active debris removal and is a vital prerequisite to achieving the ultimate goal of a cleaner Earth orbital environment.

  7. Final payload test results for the RemoveDebris active debris removal mission

    Science.gov (United States)

    Forshaw, Jason L.; Aglietti, Guglielmo S.; Salmon, Thierry; Retat, Ingo; Roe, Mark; Burgess, Christopher; Chabot, Thomas; Pisseloup, Aurélien; Phipps, Andy; Bernal, Cesar; Chaumette, François; Pollini, Alexandre; Steyn, Willem H.

    2017-09-01

    Since the beginning of the space era, a significant amount of debris has progressively been generated in space. Active Debris Removal (ADR) missions have been suggested as a way of limiting and controlling future growth in orbital space debris by actively deploying vehicles to remove debris. The European Commission FP7-sponsored RemoveDebris mission, which started in 2013, draws on the expertise of some of Europe's most prominent space institutions in order to demonstrate key ADR technologies in a cost effective ambitious manner: net capture, harpoon capture, vision-based navigation, dragsail de-orbiting. This paper provides an overview of some of the final payload test results before launch. A comprehensive test campaign is underway on both payloads and platform. The tests aim to demonstrate both functional success of the experiments and that the experiments can survive the space environment. Space environmental tests (EVT) include vibration, thermal, vacuum or thermal-vacuum (TVAC) and in some cases EMC and shock. The test flow differs for each payload and depends on the heritage of the constituent payload parts. The paper will also provide an update to the launch, expected in 2017 from the International Space Station (ISS), and test philosophy that has been influenced from the launch and prerequisite NASA safety review for the mission. The RemoveDebris mission aims to be one of the world's first in-orbit demonstrations of key technologies for active debris removal and is a vital prerequisite to achieving the ultimate goal of a cleaner Earth orbital environment.

  8. The Influence of an EPS Concrete Buffer Layer Thickness on Debris Dams Impacted by Massive Stones in the Debris Flow

    Directory of Open Access Journals (Sweden)

    Xianbin Yu

    2015-01-01

    Full Text Available The failure of debris dams impacted by the massive stones in a debris flow represents a difficult design problem. Reasonable materials selection and structural design can effectively improve the resistance impact performance of debris dams. Based on the cushioning properties of expanded polystyrene (EPS concrete, EPS concrete as a buffer layer poured on the surface of a rigid debris dam was proposed. A three-dimensional numerical calculation model of an EPS concrete buffer layer/rigid debris dam was established. The single-factor theory revealed change rules for the thickness of the buffer layer concerning the maximal impact force of the rigid debris dam surface through numerical simulation. Moreover, the impact force-time/history curves under different calculation conditions for the rigid debris dam surface were compared. Simulation results showed that the EPS concrete buffer layer can not only effectively extend the impact time of massive stones affecting the debris dam but also reduce the impact force of the rigid debris dam caused by massive stones in the debris flow. The research results provide theoretical guidance for transferring the energy of the massive stone impact, creating a structural design and optimizing debris dams.

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

    Science.gov (United States)

    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 (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.

  10. Concentration of fallout Cesium-137 in soils of the Rio de Janeiro State, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, F.C.A.; Lauria, D.C.; Silva, J.I.R., E-mail: fribeiro@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lima, E.S.A.; Amaral Sobrinho, N.M.B. do [Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropedica, RJ (Brazil); Perez, D.V. [Empresa Brasileira de Pesquisa Agropecuaria (CNPS/EMBRAPA), Rio de Janeiro, RJ (Brazil). Centro Nacional de Pesquisa de Solos

    2016-07-01

    The distribution of fallout {sup 137}Cs in soil samples of the Rio de Janeiro State was investigated. Two-hundred sixty-two samples of soil were analyzed for {sup 137}Cs by gamma spectrometry. A reference data set was built containing thirty-six detected values (14%) and two hundred twenty-six (86%) multiple detection limits of non-detected observations. Distribution pattern of the radionuclide, as well their controlling factors were evaluated based on statistical methods for censored data set (with non-detected observations). The mean of concentration values of thirty-six detected observations was 1.25 Bq.kg{sup -1}, while for the censored data sets the mean value was 0.51 Bq.kg{sup -1}. The references values for the Rio de Janeiro State were estimated as 1.44 Bq.kg{sup -1} (75{sup th}) and 1.78 Bq.kg{sup -1} (90{sup th}) (considering the year of 2015). {sup 137}Cs concentrations tend to be higher in soils with high levels of organic matter and clay and locations with high levels of these parameters would provide higher Cs fixation. No influence of the rainfall index and soil pH on the Cs content in soil was observed. The data and information gathered in this study provide valuable information for decision making purposes in case of soil contamination. (author)

  11. Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

    Science.gov (United States)

    Coppin, Frederic; Hurtevent, Pierre; Loffredo, Nicolas; Simonucci, Caroline; Julien, Anthony; Gonze, Marc-Andre; Nanba, Kenji; Onda, Yuichi; Thiry, Yves

    2016-11-01

    Our study focused on radiocaesium (137Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. 137Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0–3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61–69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees’ residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial 137Cs deposit for mature and young cedars, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, L. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States); Knight, K. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matzel, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Prussin, S. G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ryerson, F. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kinman, W. S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zimmer, M. M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hutcheon, I. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    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.

  13. Genetic consequences of radioactive contamination by the Chernobyl fallout to agricultural crops

    Energy Technology Data Exchange (ETDEWEB)

    Geraskin, S.A. E-mail: riar@obninsk.org; Dikarev, V.G.; Zyablitskaya Ye.Ya.; Oudalova, A.A.; Spirin, Ye. V; Alexakhin, R.M

    2003-07-01

    The genetic consequences of radioactive contamination by the fallout to agricultural crops after the accident at the Chernobyl NPP in 1986 have been studied. In the first, acute, period of this accident, when the absorbed dose was primarily due to external {beta}- and {gamma}-irradiation, the radiation injury of agricultural crops, according to the basic cytogenetic tests resembled the effect produced by acute {gamma}-irradiation at comparable doses. The yield of cytogenetic damage in leaf meristem of plants grown in the 10-km zone of the ChNPP in 1987-1989 (the period of chronic, lower level radiation exposure) was shown to be enhanced and dependent on the level of radioactive contamination. The rate of decline with time in cytogenetic damage induced by chronic exposure lagged considerably behind that of the radiation exposure. Analysis of genetic variability in three sequentia generations of rye and wheat revealed increased cytogenetic damage in plants exposed to chronic irradiation during the 2nd and 3rd years.

  14. Processing of analogues of plume fallout in cold regions of Enceladus by energetic electrons

    CERN Document Server

    Bergantini, A; Nair, B G; Mason, N J; Fraser, H J

    2014-01-01

    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 (approximately ninety percent), 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. 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 ...

  15. MU radar measurements of orbital debris

    Science.gov (United States)

    Sato, Toru; Kayama, Hidetoshi; Furusawa, Akira; Kimura, Iwane

    1990-04-01

    Distributions of orbital debris versus height and scattering cross section are determined from a series of observations made with a high-power VHF Doppler radar (MU radar) of Japan. An automated data processing algorithm has been developed to discriminate echoes of orbiting objects from those of undesired signals such as meteor trail echoes or lightning atmospherics. Although the results are preliminary, they showed good agreement with those from NORAD tracking radar observations using a much higher frequency. It is found that the collision frequency of a Space Station of 1 km x 1 km size at an altitude of 500 km with orbiting debris is expected to be as high as once per two years.

  16. Herschel Observations of Dusty Debris Disks

    CERN Document Server

    Vican, Laura; Bryden, Geoff; Melis, Carl; Zuckerman, B; Rhee, Joseph; Song, Inseok

    2016-01-01

    We present results from two Herschel observing programs using the Photodetector Array Camera and Spectrometer. During three separate campaigns, we obtained Herschel data for 24 stars at 70, 100, and 160 microns. We chose stars that were already known or suspected to have circumstellar dust based on excess infrared emission previously measured with IRAS or Spitzer, and used Herschel to examine long-wavelength properties of the dust. Fifteen stars were found to be uncontaminated by background sources, and possess infrared emission most likely due to a circumstellar debris disk. We analyzed the properties of these debris disks to better understand the physical mechanisms responsible for dust production and removal. Seven targets were spatially resolved in the Herschel images. Based on fits to their spectral energy distributions, nine disks appear to have two temperature components. Of these nine, in three cases, the warmer dust component is likely the result of a transient process rather than a steady state coll...

  17. Debris Dispersion Model Using Java 3D

    Science.gov (United States)

    Thirumalainambi, Rajkumar; Bardina, Jorge

    2004-01-01

    This paper describes web based simulation of Shuttle launch operations and debris dispersion. Java 3D graphics provides geometric and visual content with suitable mathematical model and behaviors of Shuttle launch. Because the model is so heterogeneous and interrelated with various factors, 3D graphics combined with physical models provides mechanisms to understand the complexity of launch and range operations. The main focus in the modeling and simulation covers orbital dynamics and range safety. Range safety areas include destruct limit lines, telemetry and tracking and population risk near range. If there is an explosion of Shuttle during launch, debris dispersion is explained. The shuttle launch and range operations in this paper are discussed based on the operations from Kennedy Space Center, Florida, USA.

  18. Proportional loss functions for debris flow events

    Directory of Open Access Journals (Sweden)

    C. M. Rheinberger

    2013-08-01

    Full Text Available Quantitative risk assessments of debris flows and other hydrogeological hazards require the analyst to predict damage potentials. A common way to do so is by use of proportional loss functions. In this paper, we analyze a uniquely rich dataset of 132 buildings that were damaged in one of five large debris flow events in Switzerland. Using the double generalized linear model, we estimate proportional loss functions that may be used for various prediction purposes including hazard mapping, landscape planning, and insurance pricing. Unlike earlier analyses, we control for confounding effects of building characteristics, site specifics, and process intensities as well as for overdispersion in the data. Our results suggest that process intensity parameters are the most meaningful predictors of proportional loss sizes. Cross-validation tests suggest that the mean absolute prediction errors of our models are in the range of 11%, underpinning the accurateness of the approach.

  19. Proportional loss functions for debris flow events

    Science.gov (United States)

    Rheinberger, C. M.; Romang, H. E.; Bründl, M.

    2013-08-01

    Quantitative risk assessments of debris flows and other hydrogeological hazards require the analyst to predict damage potentials. A common way to do so is by use of proportional loss functions. In this paper, we analyze a uniquely rich dataset of 132 buildings that were damaged in one of five large debris flow events in Switzerland. Using the double generalized linear model, we estimate proportional loss functions that may be used for various prediction purposes including hazard mapping, landscape planning, and insurance pricing. Unlike earlier analyses, we control for confounding effects of building characteristics, site specifics, and process intensities as well as for overdispersion in the data. Our results suggest that process intensity parameters are the most meaningful predictors of proportional loss sizes. Cross-validation tests suggest that the mean absolute prediction errors of our models are in the range of 11%, underpinning the accurateness of the approach.

  20. Analysis of the Mobilization of Debris Flows

    Science.gov (United States)

    1974-10-01

    as lateral ridges pestered along the canyon walls. The debris flow mobilized in a grass-covered swale surrounded by a moderately dense growth of...water apparently rushes out of the channels much as water from a firehose and strikes the talus. The erosive power of water issuing from a firehose...normal floods. The typical mudspate-track does not, however, readily associate itself with the ravine of a permanent or powerful mountain stream, for

  1. Visible Light Spectroscopy of GEO Debris

    Science.gov (United States)

    Seitzer, Patrick; Lederer, Susan M.; Cowardin, Heather; Barker, Edwin S.; Abercromby, Kira J.

    2012-01-01

    Our goal is to understand the physical characteristics of debris at geosynchronous orbit (GEO). Our approach is to compare the observed reflectance as a function of wavelength with laboratory measurements of typical spacecraft surfaces to understand what the materials are likely to be. Because debris could be irregular in shape and tumbling at an unknown rate, rapid simultaneous measurements over a range of wavelengths are required. Acquiring spectra of optically faint objects with short exposure times to minimize these effects requires a large telescope. We describe optical spectroscopy obtained during 12-14 March 2012 with the IMACS imaging spectrograph on the 6.5-m 'Walter Baade' Magellan telescope at Las Campanas Observatory in Chile. When used in f/2 imaging mode for acquisition, this instrument has a field of view of 30 arc-minutes in diameter. After acquisition and centering of a GEO object, a 2.5 arc-second wide slit and a grism are moved into the beam for spectroscopy. We used a 200 l/mm grism blazed at 660 nm for wavelength coverage in the 500-900 nm region. Typical exposure times for spectra were 15-30 seconds. Spectra were obtained for five objects in the GEO regime listed as debris in the US Space Command public catalog, and one high area to mass ratio GEO object. In addition spectra were obtained of three cataloged IDCSP (Initial Defense Communications Satellite Program) satellites with known initial properties just below the GEO regime. All spectra were calibrated using white dwarf flux standards and solar analog stars. We will describe our experiences using Magellan, a telescope never used previously for orbital debris spectroscopy, and our initial results.

  2. Europium-155 in Debris from Nuclear Weapons

    DEFF Research Database (Denmark)

    Aarkrog, Asker; Lippert, Jørgen Emil

    1967-01-01

    The lithium-drifted germanium detector enables determination of europium-155 on a routine basis in environmental samples contaminated with debris from nuclear weapons. From measurements of europium-155, cesium-144, and strontium-90 in air filters collected between 1961 and 1966, the yield...... of europium-155 from weapons was estimated at 1400 atoms per 10$^{6}$ fissions, which is close to the yield of europium-155 from fast fission of uranium-238....

  3. Orbital Debris: Past, Present, and Future

    Science.gov (United States)

    Stansbery, Gene; Johnson, Nicholas

    2013-01-01

    In the early days of spaceflight, the gBig Sky h theory was the near universally accepted paradigm for dealing with collisions of orbiting objects. This theory was also used during the early years of the aviation industry. Just as it did in aviation, the gBig Sky h theory breaks down as more and more objects accumulate in the environment. Fortunately, by the late 1970 fs some visionaries in NASA and the US Department of Defense (DoD) realized that trends in the orbital environment would inevitably lead to increased risks to operational spacecraft from collisions with other orbiting objects. The NASA Orbital Debris Program was established at and has been conducted at Johnson Space Center since 1979. At the start of 1979, fewer than 5000 objects were being tracked by the US Space Surveillance Network and very few attempts had been made to sample the environment for smaller sizes. Today, the number of tracked objects has quadrupled. Ground ]based and in situ measurements have statistically sampled the LEO environment over most sizes and mitigation guidelines and requirements are common among most space faring nations. NASA has been a leader, not only in defining the debris environment, but in promoting awareness of the issues in the US and internationally, and in providing leadership in developing policies to address the issue. This paper will discuss in broad terms the evolution of the NASA debris program from its beginnings to its present broad range of debris related research. The paper will discuss in some detail current research topics and will attempt to predict future research trends.

  4. Controlling the Growth of Future LEO Debris Populations with Active Debris Removal

    Science.gov (United States)

    Liou, J.-C.; Johnson, N. L.; Hill, N. M.

    2008-01-01

    Active debris removal (ADR) was suggested as a potential means to remediate the low Earth orbit (LEO) debris environment as early as the 1980s. The reasons ADR has not become practical are due to its technical difficulties and the high cost associated with the approach. However, as the LEO debris populations continue to increase, ADR may be the only option to preserve the near-Earth environment for future generations. An initial study was completed in 2007 to demonstrate that a simple ADR target selection criterion could be developed to reduce the future debris population growth. The present paper summarizes a comprehensive study based on more realistic simulation scenarios, including fragments generated from the 2007 Fengyun-1C event, mitigation measures, and other target selection options. The simulations were based on the NASA long-term orbital debris projection model, LEGEND. A scenario, where at the end of mission lifetimes, spacecraft and upper stages were moved to 25-year decay orbits, was adopted as the baseline environment for comparison. Different annual removal rates and different ADR target selection criteria were tested, and the resulting 200-year future environment projections were compared with the baseline scenario. Results of this parametric study indicate that (1) an effective removal strategy can be developed based on the mass and collision probability of each object as the selection criterion, and (2) the LEO environment can be stabilized in the next 200 years with an ADR removal rate of five objects per year.

  5. Tidal Debris as a Dark Matter Probe

    CERN Document Server

    Johnston, Kathryn V

    2016-01-01

    Tidal debris streams from galaxy satellites can provide insight into the dark matter distribution in halos. This is because we have more information about stars in a debris structure than about a purely random population of stars: we know that in the past they were all bound to the same dwarf galaxy; and we know that they form a dynamically cold population moving on similar orbits. They also probe a different region of the matter distribution in a galaxy than many other methods of mass determination, as their orbits take them far beyond the typical extent of those for the bulk of stars. Although conclusive results from this information have yet to be obtained, significant progress has been made in developing the methodologies for determining both the global mass distribution of the Milky Way's dark matter halo and the amount of dark matter substructure within it. Methods for measuring the halo shape are divided into "predictive methods," which predict the tidal debris properties from the progenitor satellite'...

  6. Observations, Modeling and Theory of Debris Disks

    CERN Document Server

    Matthews, Brenda C; Wyatt, Mark C; Bryden, Geoff; Eiroa, Carlos

    2014-01-01

    Main sequence stars, like the Sun, are often found to be orbited by circumstellar material that can be categorized into two groups, planets and debris. The latter is made up of asteroids and comets, as well as the dust and gas derived from them, which makes debris disks observable in thermal emission or scattered light. These disks may persist over Gyrs through steady-state evolution and/or may also experience sporadic stirring and major collisional breakups, rendering them atypically bright for brief periods of time. Most interestingly, they provide direct evidence that the physical processes (whatever they may be) that act to build large oligarchs from micron-sized dust grains in protoplanetary disks have been successful in a given system, at least to the extent of building up a significant planetesimal population comparable to that seen in the Solar System's asteroid and Kuiper belts. Such systems are prime candidates to host even larger planetary bodies as well. The recent growth in interest in debris dis...

  7. Circumstellar Debris Disks: Diagnosing the Unseen Perturber

    CERN Document Server

    Nesvold, Erika R; Vican, Laura; Farr, Will M

    2016-01-01

    The first indication of the presence of a circumstellar debris disk is usually the detection of excess infrared emission from the population of small dust grains orbiting the star. This dust is short-lived, requiring continual replenishment, and indicating that the disk must be excited by an unseen perturber. Previous theoretical studies have demonstrated that an eccentric planet orbiting interior to the disk will stir the larger bodies in the belt and produce dust via interparticle collisions. However, motivated by recent observations, we explore another possible mechanism for heating a debris disk: a stellar-mass perturber orbiting exterior to and inclined to the disk and exciting the disk particles' eccentricities and inclinations via the Kozai-Lidov mechanism. We explore the consequences of an exterior perturber on the evolution of a debris disk using secular analysis and collisional N-body simulations. We demonstrate that a Kozai-Lidov excited disk can generate a dust disk via collisions and we compare t...

  8. Plastic debris in the open ocean

    Science.gov (United States)

    Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J. Ignacio; Irigoien, Xabier; Úbeda, Bárbara; Hernández-León, Santiago; Palma, Álvaro T.; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L.; Duarte, Carlos M.

    2014-01-01

    There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean. PMID:24982135

  9. Plastic debris in the open ocean.

    Science.gov (United States)

    Cózar, Andrés; Echevarría, Fidel; González-Gordillo, J Ignacio; Irigoien, Xabier; Ubeda, Bárbara; Hernández-León, Santiago; Palma, Alvaro T; Navarro, Sandra; García-de-Lomas, Juan; Ruiz, Andrea; Fernández-de-Puelles, María L; Duarte, Carlos M

    2014-07-15

    There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.

  10. Plastic debris in the open ocean

    KAUST Repository

    Cozar, Andres

    2014-06-30

    There is a rising concern regarding the accumulation of floating plastic debris in the open ocean. However, the magnitude and the fate of this pollution are still open questions. Using data from the Malaspina 2010 circumnavigation, regional surveys, and previously published reports, we show a worldwide distribution of plastic on the surface of the open ocean, mostly accumulating in the convergence zones of each of the five subtropical gyres with comparable density. However, the global load of plastic on the open ocean surface was estimated to be on the order of tens of thousands of tons, far less than expected. Our observations of the size distribution of floating plastic debris point at important size-selective sinks removing millimeter-sized fragments of floating plastic on a large scale. This sink may involve a combination of fast nano-fragmentation of the microplastic into particles of microns or smaller, their transference to the ocean interior by food webs and ballasting processes, and processes yet to be discovered. Resolving the fate of the missing plastic debris is of fundamental importance to determine the nature and significance of the impacts of plastic pollution in the ocean.

  11. COTELS project (4) : structural investigation of solidified debris in MCCI

    Energy Technology Data Exchange (ETDEWEB)

    Zhdanov, V.; Vasilyev, Y.; Kolodeshnikov, A.; Cherepnin, Y. [National Nuclear Center, Kurchatov (Kazakhstan). Inst. of Atomic Energy; Sakaki, Isao; Nagasaka, Hideo [Nuclear Power Engineering Corp., Tokyo (Japan). Systems Safety Dept.

    2000-05-01

    Cross section of concrete trap along with solidified debris tested in COTELS test B/C, in which the interaction among core melt, water and concrete was simulated, were structurally investigated. In 6 tests out of 10 tests, particulate debris bed was formed above continuous ingot debris. The size distribution of the particulate debris was well correlated by Rosin-Rammler equation. Large amount of smallest diameter particles was obtained due to the entrainment of molten corium, decomposed concrete and oxidation of metallic components in corium associated with molten core concrete interaction (MCCI) generated gas. The upper region of the solidified debris included more concrete compositions. The concrete erosion depth, concrete degradation condition and the structure of solidified debris were evaluated to clarify the basic difference between COTELS and former tests results. Concrete erosion depth was less than that observed in MACE, WETCOR, SWISS tests. The major differences of COTELS results compared with the former test results were: 1) absence of strong adhesion of crust to melt trap side wall: 2) water penetration into debris through both eroded side wall and channels inside ingot debris: 3) absence of large void inside ingot debris: and 4) formation of pebble bed below ingot debris. All of these promoted the suppression of MCCI. (orig.)

  12. Debris-flow generation from recently burned watersheds

    Science.gov (United States)

    Cannon, S.H.

    2001-01-01

    Evaluation of the erosional response of 95 recently burned drainage basins in Colorado, New Mexico and southern California to storm rainfall provides information on the conditions that result in fire-related debris flows. Debris flows were produced from only 37 of 95 (~40 percent) basins examined; the remaining basins produced either sediment-laden streamflow or no discernable response. Debris flows were thus not the prevalent response of the burned basins. The debris flows that did occur were most frequently the initial response to significant rainfall events. Although some hillslopes continued to erode and supply material to channels in response to subsequent rainfall events, debris flows were produced from only one burned basin following the initial erosive event. Within individual basins, debris flows initiated through both runoff and infiltration-triggered processes. The fact that not all burned basins produced debris flows suggests that specific geologic and geomorphic conditions may control the generation of fire-related debris flows. The factors that best distinguish between debris-flow producing drainages and those that produced sediment-laden streamflow are drainage-basin morphology and lithology, and the presence or absence of water-repellent soils. Basins underlain by sedimentary rocks were most likely to produce debris flows that contain large material, and sand- and gravel-dominated flows were generated primarily from terrain underlain by decomposed granite. Basin-area and relief thresholds define the morphologic conditions under which both types of debris flows occur. Debris flows containing large material are more likely to be produced from basins without water-repellent soils than from basins with water repellency. The occurrence of sand-and gravel-dominated debris flows depends on the presence of water-repellent soils.

  13. Assessing the long-term probabilistic volcanic hazard for tephra fallout in Reykjavik, Iceland: a preliminary multi-source analysis

    Science.gov (United States)

    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

  14. Regional based modeling approach for rainfall-induced debris flows in the continental-climatic Northern Tien Shan (SE Kazakhstan)

    Science.gov (United States)

    Fischer, Thomas; Küfmann, Carola; Haas, Florian; Baume, Otfried; Becht, Michael

    2013-04-01

    rock fall processes or little ice age moraines. In contrast, valley-type debris flows occur in steep and debris filled gauges and couloirs. In this context both, younger storages from recent mass movements as well as older and geomorphologically inactive slope talus and moraine material are eroded. They are notably significant even in the lower montane zone. Based on the derived statistical correlations from the mapped processes potential points for debris flow cracks occurrences are calculated over the entire investigation area. In addition to the disposition analysis and modeling, the debris flow process areas (transport zone and accumulation area) were calculated by an empirical-physical GIS-based approach combining a multiple flow-path model with a 2-parameter friction model, which originally was designed for wet-snow avalanches. The model parameters and therefore the simulated process flow behavior were calibrated based on the mapped process areas. The parameter settings for flow behavior were adapted to local conditions of the debris flow catchment area. Overall, the presented investigations wants to give information on actual process behavior of debris flows in a continental-climatic mountain system as well as a possibility for GIS based regional hazard assessment and mapping.

  15. Modelling debris flows down general channels

    Directory of Open Access Journals (Sweden)

    S. P. Pudasaini

    2005-01-01

    Full Text Available This paper is an extension of the single-phase cohesionless dry granular avalanche model over curved and twisted channels proposed by Pudasaini and Hutter (2003. It is a generalisation of the Savage and Hutter (1989, 1991 equations based on simple channel topography to a two-phase fluid-solid mixture of debris material. Important terms emerging from the correct treatment of the kinematic and dynamic boundary condition, and the variable basal topography are systematically taken into account. For vanishing fluid contribution and torsion-free channel topography our new model equations exactly degenerate to the previous Savage-Hutter model equations while such a degeneration was not possible by the Iverson and Denlinger (2001 model, which, in fact, also aimed to extend the Savage and Hutter model. The model equations of this paper have been rigorously derived; they include the effects of the curvature and torsion of the topography, generally for arbitrarily curved and twisted channels of variable channel width. The equations are put into a standard conservative form of partial differential equations. From these one can easily infer the importance and influence of the pore-fluid-pressure distribution in debris flow dynamics. The solid-phase is modelled by applying a Coulomb dry friction law whereas the fluid phase is assumed to be an incompressible Newtonian fluid. Input parameters of the equations are the internal and bed friction angles of the solid particles, the viscosity and volume fraction of the fluid, the total mixture density and the pore pressure distribution of the fluid at the bed. Given the bed topography and initial geometry and the initial velocity profile of the debris mixture, the model equations are able to describe the dynamics of the depth profile and bed parallel depth-averaged velocity distribution from the initial position to the final deposit. A shock capturing, total variation diminishing numerical scheme is implemented to

  16. Debris flow hazard mapping, Hobart, Tasmania, Australia

    Science.gov (United States)

    Mazengarb, Colin; Rigby, Ted; Stevenson, Michael

    2015-04-01

    Our mapping on the many dolerite capped mountains in Tasmania indicates that debris flows are a significant geomorphic process operating there. Hobart, the largest city in the State, lies at the foot of one of these mountains and our work is focussed on identifying areas that are susceptible to these events and estimating hazard in the valley systems where residential developments have been established. Geomorphic mapping with the benefit of recent LiDAR and GIS enabled stereo-imagery has allowed us to add to and refine a landslide inventory in our study area. In addition, a dominant geomorphic model has been recognised involving headward gully retreat in colluvial materials associated with rainstorms explains why many past events have occurred and where they may occur in future. In this paper we will review the landslide inventory including a large event (~200 000m3) in 1872 that affected a lightly populated area but since heavily urbanised. From this inventory we have attempted volume-mobility relationships, magnitude-frequency curves and likelihood estimates. The estimation of volume has been challenging to determine given that the area of depletion for each debris flow feature is typically difficult to distinguish from the total affected area. However, where LiDAR data exists, this uncertainty is substantially reduced and we develop width-length relationships (area of depletion) and area-volume relationships to estimate volume for the whole dataset exceeding 300 features. The volume-mobility relationship determined is comparable to international studies and in the absence of reliable eye-witness accounts, suggests that most of the features can be explained as single event debris flows, without requiring more complex mechanisms (such as those that form temporary debris dams that subsequently fail) as proposed by others previously. Likelihood estimates have also been challenging to derive given that almost all of the events have not been witnessed, some are

  17. Characterizing Debris in the Infrared with UKIRT

    Science.gov (United States)

    Lederer, S. M.; Jah, M.; Kendrick, R.; Buckalew, B.; Frith, J. M.; Cowardin, H. M.; Bold, M.

    2015-01-01

    The United Kingdom Infrared Telescope (UKIRT) has been a major asset for the NASA Orbital Debris Program Office (OPDO) since March, 2014. With the UKIRT current contract coming to an end at the finish of FY15, there is a golden opportunity for this community to fund and gain access to UKIRT as an SSA asset through HCAR (Hawaii Center for Astronautics Research). UKIRT is the only telescope on Mauna Kea dedicated to infrared bands. Spectral coverage ranges from the near- (0.8-5µm) to the mid- to far-infrared (8-25 micrometer) regime. To date, debris observations have been collected with three instruments. Near-Infrared photometry with ZYJHK filters has been obtained with the Wide Field Camera (WFCam). Near-Infrared (1-2.5 micrometer) spectra are the focus of observations taken with the UKIRT Imager SpecTrometer (UIST). And Michelle (Mid Infrared escCHELLE) is a thermal imager-spectrometer designed for the 8-25 micrometer regime. With 35% of the telescope time allocated to ODPO, a very steady stream of data has been collected on a variety of debris targets using all the above instrumentation. Initial results from WFCam were discussed at AMOS and NISOI including analyses on IDCSPs, the MSG cooler and baffle covers. The cylindrical HS-376 buses were the focus of recent WFCam runs. Summary analyses of these works will be presented. Focus will be given to initial results of the data collected with the Cassegrain instruments, UIST and Michelle. UIST spectra were collected in September 2014, March and April 2015. Targets included a suite of HS-376 buses, well suited to investigate the signatures of blue solar panels; several dead satellites with solar array wings; Titan 3C transtage debris; the CTA Array cover, and others. In addition, Michelle mid-IR photometry was collected on a select few objects during the April 2015 run. Using WFCam, UIST and Michelle the Lockheed Martin has been observing operational satellites in the near- mid and far-infrared regime in an attempt

  18. Landslide and debris flow susceptibility zonation using TRIGRS for the 2011 Seoul landslide event

    Science.gov (United States)

    Park, D. W.; Nikhil, N. V.; Lee, S. R.

    2013-11-01

    This paper presents the results from the application of a regional, physically based stability model: Transient Rainfall Infiltration and Grid-based Regional Slope-stability analysis (TRIGRS) for a region on Woomyeon Mountain, Seoul, South Korea. This model couples an infinite-slope stability analysis with a one-dimensional analytical solution to predict the transient pore pressure response to the infiltration of rainfall. TRIGRS also adopts the geographic information system (GIS) framework for determining the whole behaviour of a slope. In this paper, we suggest an index for evaluating the results produced by the model. Particular attention is devoted to the prediction of routes of debris flow, using a runoff module. In this context, the paper compares observed landslide and debris flow events with those predicted by the TRIGRS model. The TRIGRS model, originally developed to predict shallow landslides, has been extended in this study for application to debris flows. The results predicted by the TRIGRS model are presented as safety factor (FS) maps corresponding to transient rainfall events, and in terms of debris flow paths using methods proposed by several researchers in hydrology. In order to quantify the effectiveness of the model, we proposed an index called LRclass (landslide ratio for each predicted FS class). The LRclass index is mainly applied in regions where the landslide scar area is not well defined (or is unknown), in order to avoid overestimation of the model results. The use of the TRIGRS routing module was proposed to predict the paths of debris flow, especially in areas where the rheological properties and erosion rates of the materials are difficult to obtain. Although an improvement in accuracy is needed, this module is very useful for preliminary spatio-temporal assessment over wide areas. In summary, the TRIGRS model is a powerful tool of use to decision makers for susceptibility mapping, particularly when linked with various advanced

  19. Sources of debris flow material in burned areas

    Science.gov (United States)

    Santi, P.M.; deWolfe, V.G.; Higgins, J.D.; Cannon, S.H.; Gartner, J.E.

    2008-01-01

    The vulnerability of recently burned areas to debris flows has been well established. Likewise, it has been shown that many, if not most, post-fire debris flows are initiated by runoff and erosion and grow in size through erosion and scour by the moving debris flow, as opposed to landslide-initiated flows with little growth. To better understand the development and character of these flows, a study has been completed encompassing 46 debris flows in California, Utah, and Colorado, in nine different recently burned areas. For each debris flow, progressive debris production was measured at intervals along the length of the channel, and from these measurements graphs were developed showing cumulative volume of debris as a function of channel length. All 46 debris flows showed significant bulking by scour and erosion, with average yield rates for each channel ranging from 0.3 to 9.9??m3 of debris produced for every meter of channel length, with an overall average value of 2.5??m3/m. Significant increases in yield rate partway down the channel were identified in 87% of the channels, with an average of a three-fold increase in yield rate. Yield rates for short reaches of channels (up to several hundred meters) ranged as high as 22.3??m3/m. Debris was contributed from side channels into the main channels for 54% of the flows, with an average of 23% of the total debris coming from those side channels. Rill erosion was identified for 30% of the flows, with rills contributing between 0.1 and 10.5% of the total debris, with an average of 3%. Debris was deposited as levees in 87% of the flows, with most of the deposition occurring in the lower part of the basin. A median value of 10% of the total debris flow was deposited as levees for these cases, with a range from near zero to nearly 100%. These results show that channel erosion and scour are the dominant sources of debris in burned areas, with yield rates increasing significantly partway down the channel. Side channels are

  20. LEGEND, a LEO-to-GEO Environment Debris Model

    Science.gov (United States)

    Liou, Jer Chyi; Hall, Doyle T.

    2013-01-01

    LEGEND (LEO-to-GEO Environment Debris model) is a three-dimensional orbital debris evolutionary model that is capable of simulating the historical and future debris populations in the near-Earth environment. The historical component in LEGEND adopts a deterministic approach to mimic the known historical populations. Launched rocket bodies, spacecraft, and mission-related debris (rings, bolts, etc.) are added to the simulated environment. Known historical breakup events are reproduced, and fragments down to 1 mm in size are created. The LEGEND future projection component adopts a Monte Carlo approach and uses an innovative pair-wise collision probability evaluation algorithm to simulate the future breakups and the growth of the debris populations. This algorithm is based on a new "random sampling in time" approach that preserves characteristics of the traditional approach and captures the rapidly changing nature of the orbital debris environment. LEGEND is a Fortran 90-based numerical simulation program. It operates in a UNIX/Linux environment.

  1. Debris-flow susceptibility of watersheds recently burned by wildfire

    Science.gov (United States)

    Cannon, S.H.

    2004-01-01

    Evaluation of the erosional response of 95 recently burned watersheds in Colorado, New Mexico, and southern California to storm rainfall established the factors that best differentiate between debris-flow producing basins and those that produced other flow responses. These factors are drainage-basin morphology and lithology, and the presence or absence of water-repellent soils. Basins underlain by sedimentary rocks were most likely to produce debris flows that contain large material, and sand- and gravel-dominated debris flows were generated primarily from terrain underlain by decomposed granite. Basin-area and relief thresholds define the morphologic conditions under which both types of debris flows occurred. Debris flows containing large material were more likely to be produced from basins without water-repellent soils than from basins with water repellency. The occurrence of sand and gravel-dominated debris flows depended on the presence of water repellent soils. Copyright 2004 ASCE.

  2. Experiments for the Validation of Debris and Shrapnel Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Koniges, A E; Andrew, J; Eder, D; Kalantar, D; Masters, N; Fisher, A; Anderson, R; Gunney, B; Brown, B; Sain, K; Tobin, A M; Debonnel, C; Gielle, A; Combis, P; Jadaud, J P; Meyers, M; Jarmakani, H

    2007-08-29

    The debris and shrapnel generated by laser targets are important factors in the operation of a large laser facility such as NIF, LMJ, and Orion. Past experience has shown that it is possible for such target debris to render diagnostics inoperable and also to penetrate or damage optical protection (debris) shields. We are developing the tools to allow evaluation of target configurations in order to better mitigate the generation and impact of debris, including development of dedicated modeling codes. In order to validate these predictive simulations, we briefly describe a series of experiments aimed at determining the amount of debris and/or shrapnel produced in controlled situations. We use glass and aerogel to capture generated debris/shrapnel. The experimental targets include hohlraums (halfraums) and thin foils in a variety of geometries. Post-shot analysis includes scanning electron microscopy and x-ray tomography. We show the results of some of these experiments and discuss modeling efforts.

  3. Dynamics of unusual debris flows on Martian sand dunes

    OpenAIRE

    Bourke, Mary

    2004-01-01

    PUBLISHED Gullies that dissect sand dunes in Russell impact crater often display debris flow-like deposits in their distal reaches. The possible range of both the rheological properties and the flow rates are estimated using a numerical simulation code of a Bingham plastic flow to help explain the formation of these features. Our simulated results are best explained by a rapid debris flow. For example, a debris flow with the viscosity of 10 2 Pa s and the yiel...

  4. Classification of debris flow phenomena in the Faroe Islands

    DEFF Research Database (Denmark)

    Dahl, Mads-Peter Jakob; E. Mortensen, Lis; Jensen, Niels H.

    2012-01-01

    Landslides and debris flow phenomena in particular constitute a threat to human activities in the Faroe Islands. As a contribution to ongoing landslide risk management research, this paper proposes a classification scheme for debris flow phenomena in the Faroe Islands. The scheme, produced through...... with international landslide classification systems, significantly increases the knowledge of debris flow phenomena and promotes a consistent terminology of these within the Faroe Islands....

  5. Mapping debris-flow hazard in Honolulu using a DEM

    Science.gov (United States)

    Ellen, Stephen D.; Mark, Robert K.; ,

    1993-01-01

    A method for mapping hazard posed by debris flows has been developed and applied to an area near Honolulu, Hawaii. The method uses studies of past debris flows to characterize sites of initiation, volume at initiation, and volume-change behavior during flow. Digital simulations of debris flows based on these characteristics are then routed through a digital elevation model (DEM) to estimate degree of hazard over the area.

  6. Improvements to Filter Debris Analysis in Aviation Propulsion Systems

    Science.gov (United States)

    2012-12-01

    filter patch containing the ferromagnetic debris is typically of most interest as critical oil- wetted components are typically made from ferrous alloys ...are typically manufactured using special steels with specific alloying elements. Elemental analysis using a Scanning electron Microscope (SEM) with...debris patch (left) and extracted ferrous debris patch (right) 2.2.1 Results A total of 48 filters were analysed during the trial from all four

  7. Medical status of Marshallese accidentally exposed to 1954 Bravo fallout radiation: January 1988 through December 1991

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Using total beta-activity measurements in milk to derive thyroid doses from Chernobyl fallout.

    Science.gov (United States)

    Drozdovitch, V; Germenchuk, M; Bouville, A

    2006-01-01

    Following the Chernobyl accident, more than 200 childhood thyroid cancer cases have been observed in Brest Oblast of Belarus in territories slightly contaminated with 137Cs, but with suspected relatively high 131I fallout. The most helpful measurements available that can be used to estimate thyroid doses for the population of Brest Oblast are the total beta-activity measurements in cow's milk performed using DP-100 device within a few weeks after the accident. The 131I concentrations in milk were derived from the total beta-activity measurements on the basis of (1) a radioecological model used to estimate the variation with time of the radionuclide composition in milk and (2) the determination of the calibration factors of the DP-100 device for the most important radionuclides present in milk. As a result, 131I concentrations in milk were reconstructed for territories with different levels of 137Cs deposition. A non-linear dependence of the 131I concentration in milk on the 137Cs deposition density was obtained; it was used to estimate the thyroid doses from the consumption of 131I-contaminated cow's milk by the population of Brest Oblast. The average individual thyroid doses have been estimated to be 0.15, 0.18, 0.12, 0.06, 0.04 and 0.03 Gy for newborn, children aged 1, 5, 10 and 15 y and adults, respectively. The collective thyroid dose for the entire population of Brest Oblast is estimated to be 64,500 man Gy, the contribution from the adult population being about one half of the total. The methodology that is described could be applied in the framework of epidemiological studies of the relationship between radiation exposure to the thyroid gland and thyroid cancer in areas where numerous total beta-activity measurements in cow's milk were performed within a few weeks after the accident.

  9. Distribution of global fallouts cesium-137 in taiga and tundra catenae at the Ob River basin

    Science.gov (United States)

    Semenkov, I. N.; Usacheva, A. A.; Miroshnikov, A. Yu.

    2015-03-01

    The classification of soil catenae at the Ob River basin is developed and applied. This classification reflects the diverse geochemical conditions that led to the formation of certain soil bodies, their combinations and the migration fields of chemical elements. The soil and geochemical diversity of the Ob River basin catenae was analyzed. The vertical and lateral distribution of global fallouts cesium-137 was studied using the example of the four most common catenae types in Western Siberia tundra and taiga. In landscapes of dwarf birches and dark coniferous forests on gleysols, cryosols, podzols, and cryic-stagnosols, the highest 137Cs activity density and specific activity are characteristic of the upper soil layer of over 30% ash, while the moss-grass-shrub cover is characterized by low 137Cs activity density and specific activity. In landscapes of dwarf birches and pine woods on podzols, the maximum specific activity of cesium-137 is typical for moss-grass-shrub cover, while the maximum reserves are concentrated in the upper soil layer of over 30% ash. Bog landscapes and moss-grass-shrub cover are characterized by a minimum activity of 137Cs, and its reserves in soil generally decrease exponentially with depth. The cesium-137 penetration depth increases in oligotrophic histosols from northern to middle taiga landscapes from 10-15 to 40 cm. 137Cs is accumulated in oligotrophic histosols for increases in pH from 3.3 to 4.0 and in concretionary interlayers of pisoplinthic-cryic-histic-stagnosols. Cryogenic movement, on the one hand, leads to burying organic layers enriched in 137Cs and, on the other hand, to deducing specific activity when mixed with low-active material from lower soil layers.

  10. Modeling the fallout from stabilized nuclear clouds using the HYSPLIT atmospheric dispersion model.

    Science.gov (United States)

    Rolph, G D; Ngan, F; Draxler, R R

    2014-10-01

    The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, developed by the National Oceanic and Atmospheric Administration's Air Resources Laboratory, has been configured to simulate the dispersion and deposition of nuclear materials from a surface-based nuclear detonation using publicly available information on nuclear explosions. Much of the information was obtained from "The Effects of Nuclear Weapons" by Glasstone and Dolan (1977). The model was evaluated against the measurements of nuclear fallout from six nuclear tests conducted between 1951 and 1957 at the Nevada Test Site using the global NCEP/NCAR Reanalysis Project (NNRP) and the Weather Research and Forecasting (WRF) meteorological data as input. The model was able to reproduce the general direction and deposition patterns using the coarse NNRP data with Figure of Merit in Space (FMS - the percent overlap between predicted and measured deposition patterns) scores in excess of 50% for four of six simulations for the smallest dose rate contour, with FMS scores declining for higher dose rate contours. When WRF meteorological data were used the FMS scores were 5-20% higher in five of the six simulations, especially at the higher dose rate contours. The one WRF simulation where the scores declined slightly (10-30%) was also the best scoring simulation when using the NNRP data. When compared with measurements of dose rate and time of arrival from the Town Data Base (Thompson et al., 1994), similar results were found with the WRF simulations providing better results for four of six simulations. The overall result was that the different plume simulations using WRF data had more consistent performance than the plume simulations using NNRP data fields.

  11. Processing of analogues of plume fallout in cold regions of Enceladus by energetic electrons

    Science.gov (United States)

    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.

  12. Debris flows of the Simud-Tiu outflow system of Mars

    Science.gov (United States)

    Tanaka, Kenneth L.

    1988-01-01

    It is seen that the magnitude of geologic happenings are commonly quite different between the Earth and Mars because of differences in the makeup and breakup of their crusts. By assessing the differences, and the similarities, between planets, the geologic history of Mars can be more fully understood. The identification of debris-flow deposits in channels of Mars, for example, helps to establish which of several competing explanations for the origin of the channels actually occurred. In turn, the Earth is viewed in new, and commonly enlightening perspectives. By the way, it is fortunate that on Earth, thick sequences of impact ejected are not found that could be transformed into the monstrous debris flows that have devastated the Martian surface.

  13. Cleaning space debris with a space-based laser system

    Institute of Scientific and Technical Information of China (English)

    Shen Shuangyan; Jin Xing; Chang Hao

    2014-01-01

    High-energy pulsed laser radiation may be the most feasible means to mitigate the threat of collision of a space station or other valuable space assets with orbital debris in the size range of 1-10 cm. Under laser irradiation, part of the debris material is ablated and provides an impulse to the debris particle. Proper direction of the impulse vector either deflects the object trajectory or forces the debris on a trajectory through the upper atmosphere, where it burns up. Most research concentrates on ground-based laser systems but pays little attention to space-based laser systems. There are drawbacks of a ground-based laser system in cleaning space debris. Therefore the placement of a laser system in space is proposed and investigated. Under assumed conditions, the elimination process of space debris is analyzed. Several factors such as laser repetition frequency, relative movement between the laser and debris, and inclination of debris particles which may exercise influence to the elimination effects are discussed. A project of a space-based laser system is proposed according to the numerical results of a computer study. The proposed laser system can eliminate debris of 1-10 cm and succeed in protecting a space station.

  14. Orbital Debris Quarterly News. Volume 13; No. 1

    Science.gov (United States)

    Liou, J.-C. (Editor); Shoots, Debi (Editor)

    2009-01-01

    Topics discussed include: new debris from a decommissioned satellite with a nuclear power source; debris from the destruction of the Fengyun-1C meteorological satellite; quantitative analysis of the European Space Agency's Automated Transfer Vehicle 'Jules Verne' reentry event; microsatellite impact tests; solar cycle 24 predictions and other long-term projections and geosynchronus (GEO) environment for the Orbital Debris Engineering Model (ORDEM2008). Abstracts from the NASA Orbital Debris Program Office, examining satellite reentry risk assessments and statistical issues for uncontrolled reentry hazards, are also included.

  15. Debris disks and the search for life in the universe

    CERN Document Server

    Cataldi, Gianni

    2016-01-01

    Circumstellar debris disks are the extrasolar analogues of the asteroid belt and the Kuiper belt. They consist of comets and leftover planetesimals that continuously collide and produce circumstellar dust that can be observed as infrared excess or in resolved imaging. As an obvious outcome of the planet formation process, debris disks can help us constrain planet formation theories and learn about the history of our own solar system. This thesis presents observational studies of secondary gas in debris disks. It also discusses the astrobiological potential of debris disks created during impact events onto exoplanets.

  16. Radar Measurements of Small Debris from HUSIR and HAX

    Science.gov (United States)

    Hamilton J.; Blackwell, C.; McSheehy, R.; Juarez, Q.; Anz-Meador, P.

    2017-01-01

    For many years, the NASA Orbital Debris Program Office has been collecting measurements of the orbital debris environment from the Haystack Ultra-wideband Satellite Imaging Radar (HUSIR) and its auxiliary (HAX). These measurements sample the small debris population in low earth orbit (LEO). This paper will provide an overview of recent observations and highlight trends in selected debris populations. Using the NASA size estimation model, objects with a characteristic size of 1 cm and larger observed from HUSIR will be presented. Also, objects with a characteristic size of 2 cm and larger observed from HAX will be presented.

  17. Debris Flow Hazard Assessment Based on Support Vector Machine

    Institute of Scientific and Technical Information of China (English)

    YUAN Lifeng; ZHANG Youshui

    2006-01-01

    Seven factors, including the maximum volume of once flow , occurrence frequency of debris flow , watershed area , main channel length , watershed relative height difference , valley incision density and the length ratio of sediment supplement are chosen as evaluation factors of debris flow hazard degree. Using support vector machine (SVM) theory, we selected 259 basic data of 37 debris flow channels in Yunnan Province as learning samples in this study. We create a debris flow hazard assessment model based on SVM. The model was validated though instance applications and showed encouraging results.

  18. Calculation of the debris flow concentration based on clay content

    Institute of Scientific and Technical Information of China (English)

    CHEN Ningsheng; CUI Peng; LIU Zhonggang; WEI Fangqiang

    2003-01-01

    The debris flow clay content has very tremendous influence on its concentration (γC). It is reported that the concentration can be calculated by applying the relative polynomial based on the clay content. Here one polynomial model and one logarithm model to calculate the concentration based on the clay content for both the ordinary debris flow and viscous debris flow are obtained. The result derives from the statistics and analysis of the relationship between the debris flow concentrations and clay content in 45 debris flow sites located in the southwest of China. The models can be applied for the concentration calculation to those debris flows that are impossible to observe. The models are available to calculate the debris flow concentration, the principles of which are in the clay content affecting on the debris flow formation, movement and suspending particle diameter. The mechanism of the relationship of the clay content and concentration is clear and reliable. The debris flow is usually of micro-viscous when the clay content is low (<3%), by analyzing the developing tendency on the basics of the relationship between the clay content and debris flow concentration. Indeed, the less the clay content, the less the concentration for most debris flows. The debris flow tends to become the water rock flow or the hyperconcentrated flow with the clay content decrease. Through statistics it is apt to transform the soil into the viscous debris flow when the clay content of ranges is in 3%-18%. Its concentration increases with the increasing of the clay content when the clay content is between 5% and 10%. But the value decreases with the increasing of the clay content when the clay content is between 10% and 18%. It is apt to transform the soil into the mudflow, when the clay content exceeds 18%. The concentration of the mudflow usually decreases with the increase of the clay content, and this developing tendency reverses to that of the micro-viscous debris flow. There is

  19. Radar Measurements of Small Debris from HUSIR and HAX

    Science.gov (United States)

    Hamilton, Joseph; Blackwell, Chris; McSheehy, Richard; Juarez, Quanette

    2017-01-01

    For many years, the NASA Orbital Debris Program Office has been collecting measurements of the orbital debris environment from the Haystack Ultra-wideband Satellite Imaging Radar (HUSIR) and its auxiliary (HAX). These measurements sample the small debris population in low earth orbit (LEO). This paper will provide an overview of recent observations and highlight trends in selected debris populations. Using the NASA size estimation model, objects with a characteristic size of 1 cm and larger observed from HUSIR will be presented. Also, objects with a characteristic size of 2 cm and larger observed from HAX will be presented.

  20. The Research of Space debris Based on AHP

    Institute of Scientific and Technical Information of China (English)

    Wu Mengxiang; Dong Xue; Gao Long

    2016-01-01

    Space debris is called the image of space junk. In this paper, the deifnition and classiifcation of space debris are studied. The processing methods of space debris and the earnings of the company are analyzed. In view of the above problems, proposed algorithm based on analytic hierarchy process (AHP) ifnally, use MATLAB programming to obtain the simulation results, and verify the true results are correct. The innovation of this paper is to propose the method of analytic hierarchy process to solve the problem of space debris.

  1. Wear Debris Identification Using Feature Extraction and Neural Network

    Institute of Scientific and Technical Information of China (English)

    王伟华; 马艳艳; 殷勇辉; 王成焘

    2004-01-01

    A method and results of identification of wear debris using their morphological features are presented. The color images of wear debris were used as initial data. Each particle was characterized by a set of numerical parameters combined by its shape, color and surface texture features through a computer vision system. Those features were used as input vector of artificial neural network for wear debris identification. A radius basis function (RBF) network based model suitable for wear debris recognition was established,and its algorithm was presented in detail. Compared with traditional recognition methods, the RBF network model is faster in convergence, and higher in accuracy.

  2. Space debris: Assessing risk and responsibility

    Science.gov (United States)

    Bradley, Andrew M.; Wein, Lawrence M.

    2009-05-01

    We model the orbital debris environment by a set of differential equations with parameter values that capture many of the complexities of existing three-dimensional simulation models. We compute the probability that a spacecraft gets destroyed in a collision during its operational lifetime, and then define the sustainable risk level as the maximum of this probability over all future time. Focusing on the 900- to 1000-km altitude region, which is the most congested portion of low Earth orbit, we find that - despite the initial rise in the level of fragments - the sustainable risk remains below 10-3 if there is high (>98%) compliance to the existing 25-year postmission deorbiting guideline. We quantify the damage (via the number of future destroyed operational spacecraft) generated by past and future space activities. We estimate that the 2007 FengYun 1C antisatellite weapon test represents ≈1% of the legacy damage due to space objects having a characteristic size of ⩾10 cm, and causes the same damage as failing to deorbit 2.6 spacecraft after their operational life. Although the political and economic issues are daunting, these damage estimates can be used to help determine one-time legacy fees and fees on future activities (including deorbit noncompliance), which can deter future debris generation, compensate operational spacecraft that are destroyed in future collisions, and partially fund research and development into space debris mitigation technologies. Our results need to be confirmed with a high-fidelity three-dimensional model before they can provide the basis for any major decisions made by the space community.

  3. The Population of Optically Faint GEO Debris

    Science.gov (United States)

    Seitzer, Patrick; Barker, Ed; Buckalew, Brent; Burkhardt, Andrew; Cowardin, Heather; Frith, James; Gomez, Juan; Kaleida, Catherine; Lederer, Susan M.; Lee, Chris H.

    2016-01-01

    The 6.5-m Magellan telescope 'Walter Baade' at the Las Campanas Observatory in Chile has been used for spot surveys of the GEO orbital regime to study the population of optically faint GEO debris. The goal is to estimate the size of the population of GEO debris at sizes much smaller than can be studied with 1-meter class telescopes. Despite the small size of the field of view of the Magellan instrument (diameter 0.5-degree), a significant population of objects fainter than R = 19th magnitude have been found with angular rates consistent with circular orbits at GEO. We compare the size of this population with the numbers of GEO objects found at brighter magnitudes by smaller telescopes. The observed detections have a wide range in characteristics starting with those appearing as short uniform streaks. But there are a substantial number of detections with variations in brightness, flashers, during the 5-second exposure. The duration of each of these flashes can be extremely brief: sometimes less than half a second. This is characteristic of a rapidly tumbling object with a quite variable projected size times albedo. If the albedo is of the order of 0.2, then the largest projected size of these objects is around 10-cm. The data in this paper was collected over the last several years using Magellan's IMACS camera in f/2 mode. The analysis shows the brightness bins for the observed GEO population as well as the periodicity of the flashers. All objects presented are correlated with the catalog: the focus of the paper will be on the uncorrelated, optically faint, objects. The goal of this project is to better characterize the faint debris population in GEO that access to a 6.5-m optical telescope in a superb site can provide.

  4. A Parametric Study on Using Active Debris Removal to Stabilize the Future LEO Debris Environment

    Science.gov (United States)

    Liou, J.C.

    2010-01-01

    Recent analyses of the instability of the orbital debris population in the low Earth orbit (LEO) region and the collision between Iridium 33 and Cosmos 2251 have reignited the interest in using active debris removal (ADR) to remediate the environment. There are; however, monumental technical, resources, operational, legal, and political challenges in making economically viable ADR a reality. Before a consensus on the need for ADR can be reached, a careful analysis of the effectiveness of ADR must be conducted. The goal is to demonstrate the feasibility of using ADR to preserve the future environment and to guide its implementation to maximize the benefit-cost ratio. This paper describes a comprehensive sensitivity study on using ADR to stabilize the future LEO debris environment. The NASA long-term, orbital debris evolutionary model, LEGEND, is used to quantify the effects of many key parameters. These parameters include (1) the starting epoch of ADR implementation, (2) various target selection criteria, (3) the benefits of collision avoidance maneuvers, (4) the consequence of targeting specific inclination or altitude regimes, (5) the consequence of targeting specific classes of vehicles, and (6) the timescale of removal. Additional analyses on the importance of postmission disposal and how future launches might affect the requirements to stabilize the environment are also included.

  5. Engagement of Metal Debris into Gear Mesh

    Science.gov (United States)

    handschuh, Robert F.; Krantz, Timothy L.

    2010-01-01

    A series of bench-top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

  6. Live Worms Found Amid STS-107 Debris

    Science.gov (United States)

    2003-01-01

    NASA Project Manager Fred Ahmay holds a Biological Research in Canisters (BRIC) container in which C. elegans nemotodes (round worms) were found. The container was part of a middeck experiment that was among Columbia's debris recovered in East Texas. The worms were found alive after flying on Columbia's last mission, STS-107. The experiment was designed to verify a new synthetic nutrient solution for an International Space Station 'model' specimen planned to be used extensively for ISS gene expression studies and was sponsored by the NASA Ames Research Center. For more information on STS-107, please see GRIN Columbia General Explanation

  7. Explorations of Dusty Debris Disk Geometry

    CERN Document Server

    Dennihy, E; Clemens, J C

    2016-01-01

    As the sample of white dwarfs with signatures of planetary systems has grown, statistical studies have begun to suggest our picture of compact debris disk formation from disrupted planetary bodies is incomplete. Here we present the results of an effort to extend the preferred dust disk model introduced by \\citet{jur03} to include elliptical geometries. We apply this model the observed distribution of fractional infrared luminosities, and explore the difference in preferred parameter spaces for a circular and highly elliptical model on a well-studied dusty white dwarf.

  8. Missing Mass in Collisional Debris from Galaxies

    CERN Document Server

    Bournaud, F; Brinks, E; Boquien, M; Amram, P; Lisenfeld, U; Koribalski, B S; Walter, F; Charmandaris, V

    2007-01-01

    Recycled dwarf galaxies can form in the collisional debris of massive galaxies. Theoretical models predict that, contrary to classical galaxies, they should be free of non-baryonic Dark Matter. Analyzing the observed gas kinematics of such recycled galaxies with the help of a numerical model, we demonstrate that they do contain a massive dark component amounting to about twice the visible matter. Staying within the standard cosmological framework, this result most likely indicates the presence of large amounts of unseen, presumably cold, molecular gas. This additional mass should be present in the disks of their progenitor spiral galaxies, accounting for a significant part of the so-called missing baryons.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. - Highlights: • Transfer of radiocesium atmospheric fallout in evergreen forests was modeled. • The model was tested using observations from Chernobyl and Fukushima accidents. • Model predictions of canopy interception and depuration agree with measurements. • Unexpectedly high contribution of litterfall for the

  10. Investigation of Orbital Debris: Mitigation, Removal, and Modeling the Debris Population

    Science.gov (United States)

    Slotten, Joel

    The population of objects in orbit around Earth has grown since the late 1950s. Today there are over 21,000 objects over 10 cm in length in orbit, and an estimated 500,000 more between 1 and 10 cm. Only a small fraction of these objects are operational satellites. The rest are debris: old derelict spacecraft or rocket bodies, fragments created as the result of explosions or collisions, discarded objects, slag from solid rockets, or even flaked off paint. Traveling at up to 7 km/s, a collision with even a 1 cm piece of debris could severely damage or destroy a satellite. This dissertation examines three aspects of orbital debris. First, the concept of a self-consuming satellite is explored. This nanosatellite would use its own external structure as propellant to execute a deorbit maneuver at the end of its operational life, thus allowing it to meet current debris mitigation standards. Results from lab experiments examining potential materials for this concept have shown favorable results. Second, Particle in Cell techniques are modified and used to model the plasma plume from a micro-cathode arc thruster. This model is then applied to the concept of an ion beam shepherd satellite. This satellite would use its plasma plume to deorbit another derelict satellite. Results from these simulations indicate the micro-cathode arc thruster could potentially deorbit a derelict CubeSat in a matter of a few weeks. Finally, the orbital debris population at geosynchronous orbit is examined, focusing on variations in the density of the population as a function of longitude. New insights are revealed demonstrating that the variation in population density is slightly less than previously reported.

  11. The decline of mountain permafrost and the occurrence of recent large debris slides in Iceland

    Science.gov (United States)

    Saemundsson, Thorsteinn; Kristinn Helgason, Jon; Petursson, Halldor

    2014-05-01

    During the last decade several, somewhat unusual, debris slides have occurred in Iceland. Most of these slides occurred in the Tröllaskagi peninsula in central north Iceland as well as in the eastern part of the island, and their starting zones are all located above 750-800 m. In most of them large blocks of frozen sediments have been observed in the slide material. The temperature rise which has been observed in Iceland during the last decades has lead to discussions about the present permafrost condition in Iceland and the possible decline of mountain permafrost. Recent studies at the Orravatnsrústir palsa site, in the highlands north of the Hofsjökull icecap give clear indications of decreasing of the permafrost during the last decade or so (Saemundsson et al. 2012). In 2011 and 2012 two large debris slides occurred in northern Iceland. In 2011 a huge slide fell from the Torfufell Mountain in the Eyjafjörður area and in 2012 another one fell from the Móafellshyrna Mountain in the Fljót area. In both these cases the slides originated at about 750-800 m a.s.l. and large chunks of frozen sediments transported down the mountain sides. The Torfufell debris slide fell on the 14th of October 2011, after exceptionally warm summer and unusually rainy fall. The slide originated along a 200 m long fissure at 800 m.a.s.l in a NW facing slope. Big blocks of frozen sediments located within the landslide debris material were traced back to crown of the landslide. The, Móafellshyrna debris slide fell on the 20th of September 2012, occurred after an unusually warm and dry summer with record amount of sunshine hours, followed by month of intense precipitation and earthquake activity in N-Iceland. The slide originated in a 200 m wide cirque at 750 m height in the NW slope of the mountain where a frozen solid debris cone slid or crept off a 100 m high rock face into a steep water saturated talus slope. The frozen sediments at 750 m height give clear indication of mountain

  12. ALMA Observations of the Molecular Gas in the Debris Disk of the 30 Myr Old Star HD 21997

    Science.gov (United States)

    Kospal, A.; Moor, A.; Juhasz, A.; Abraham, P.; Apai, D.; Csengeri, T.; Grady, C. A.; Henning, Th.; Hughes, A. M.; Kiss, Cs.; Pascucci, I.; Schmalzl, M.

    2013-01-01

    The 30 Myr old A3-type star HD 21997 is one of the two known debris dust disks having a measurable amount of cold molecular gas. With the goal of understanding the physical state, origin, and evolution of the gas in young debris disks, we obtained CO line observations with the Atacama Large Millimeter/submillimeter Array (ALMA). Here, we report on the detection of (12)CO and (13)CO in the J = 2-1 and J = 3-2 transitions and C(18)O in the J = 2-1 line. The gas exhibits a Keplerian velocity curve, one of the few direct measurements of Keplerian rotation in young debris disks. The measured CO brightness distribution could be reproduced by a simple star+disk system, whose parameters are r(sub in) ALMA continuum observations by Moor et al., we conclude that comparable amounts of CO gas and dust are present in the disk. Interestingly, the gas and dust in the HD 21997 system are not colocated, indicating a dust-free inner gas disk within 55 AU of the star. We explore two possible scenarios for the origin of the gas. A secondary origin, which involves gas production from colliding or active planetesimals, would require unreasonably high gas production rates and would not explain why the gas and dust are not colocated. We propose that HD 21997 is a hybrid system where secondary debris dust and primordial gas coexist. HD 21997, whose age exceeds both the model predictions for disk clearing and the ages of the oldest T Tauri-like or transitional gas disks in the literature, may be a key object linking the primordial and the debris phases of disk evolution.

  13. Debris disks in main sequence binary systems

    CERN Document Server

    Trilling, D E; Stapelfeldt, K R; Rieke, G H; Su, K Y L; Gray, R O; Corbally, C J; Bryden, G; Chen, C H; Boden, A; Beichman, C A

    2006-01-01

    We observed 69 A3-F8 main sequence binary star systems using the Multiband Imaging Photometer for Spitzer onboard the Spitzer Space Telescope. We find emission significantly in excess of predicted photospheric flux levels for 9(+4/-3)% and 40(+7/-6)% of these systems at 24 and 70 microns, respectively. Twenty two systems total have excess emission, including four systems that show excess emission at both wavelengths. A very large fraction (nearly 60%) of observed binary systems with small (<3 AU) separations have excess thermal mission. We interpret the observed infrared excesses as thermal emission from dust produced by collisions in planetesimal belts. The incidence of debris disks around main sequence A3-F8 binaries is marginally higher than that for single old AFGK stars. Whatever combination of nature (birth conditions of binary systems) and nurture (interactions between the two stars) drives the evolution of debris disks in binary systems, it is clear that planetesimal formation is not inhibited to a...

  14. Early deterioration of coarse woody debris.

    Energy Technology Data Exchange (ETDEWEB)

    Tainter, Frank, H.; McMinn, James, W.

    1999-02-16

    Tainter, F.H., and J.W. McMinn. 1999. Early deterioration of coarse woody debris. In: Proc. Tenth Bien. South. Silv. Res. Conf. Shreveport, LA, February 16-18, 1999. Pp. 232-237 Abstract - Coarse woody debris (CWD) is an important structural component of southern forest ecosystems. CWD loading may be affected by different decomposition rates on sites of varying quality. Bolts of red oak and loblolly pine were placed on plots at each of three (hydric, mesic. and xerlc) sites at the Savannah River Site and sampled over a I6-week period. Major changes were in moisture content and nonstructural carbohydrate content (total carbohydrates, reducing sugars, and starch) of sapwood. Early changes in nonstructural carbohydrate levels following placement of the bolts were likely due to reallocation of these materials by sapwood parenchyma cells. These carbohydrates later formed pools increasingly metabolized by bacteria and invading fungi. Most prevalent fungi in sapwood were Ceratocysfis spp. in pine and Hypoxy/on spp. in oak. Although pine sapwood became blue stained and oak sapwood exhibited yellow soft decay with black zone lines, estimators of decay (specific gravity, sodium hydroxide solubility, and holocellulose content) were unchanged during the 16-week study period. A small effect of site was detected for starch content of sapwood of both species. Fungal biomass in sapwood of both species, as measured by ergosterol content, was detectable at week zero, increased somewhat by week three and increased significantly by week 16.

  15. Active Polarimetry for Orbital Debris Identification

    Science.gov (United States)

    Pasqual, M.; Cahoy, C.

    We present the results of polarimetric measurements that may help remotely identify orbital debris fragments, thereby extending current space surveillance capabilities. A bench-top polarimeter (wavelength 1064 nm) was used to experimentally determine the polarimetric Bidirectional Reflectance Distribution Function (BRDF) of several common spacecraft materials and coatings, including glossy white paint, matte black paint, black Kapton®, silver Teflon®, aluminum, and titanium. Analysis of these measurements allowed us to estimate each material's Mueller matrix and associated polarimetric properties as a function of the incident angle and (bistatic) in-plane scatter angle. Results revealed notable trends in the materials' polarimetric signatures. Specifically, the materials exhibited mostly weak diattenuation (D 0.5 in the forward scatter direction). In terms of retardance (R), silver Teflon® exhibited a finite range of values (R = 30 to 120º) in all directions, while the other materials acted as mirrors (R = 180º) in the back scatter direction and had the full range of behavior (R = 0 to 180º) in the forward scatter direction. Finally, in terms of depolarization power (Delta), glossy white paint was a nearly perfect depolarizer (Delta = 1) in the back scatter direction, but sharply lost depolarization power (Delta = 0) at specular reflection. All other materials were mostly weak depolarizers (Delta < 0.5) in all scatter directions. These experimental findings may be used to develop requirements for a polarimetric laser radar that can interrogate debris fragments, identify their constituent materials, and infer their masses and other characteristics of interest.

  16. Abundances in Stars with Debris Disks

    CERN Document Server

    Ritchey, Adam M; Stone, Myra; Wallerstein, George

    2013-01-01

    We present preliminary results of a detailed chemical abundance analysis for a sample of solar-type stars known to exhibit excess infrared emission associated with dusty debris disks. Our sample of 28 stars was selected based on results from the Formation and Evolution of Planetary Systems (FEPS) Spitzer Legacy Program, for the purpose of investigating whether the stellar atmospheres have been polluted with planetary material, which could indicate that the metallicity enhancement in stars with planets is due to metal-rich infall in the later stages of star and planet formation. The preliminary results presented here consist of precise abundances for 15 elements (C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Fe, Co, and Ni) for half of the stars in our sample. We find that none of the stars investigated so far exhibit the expected trend of increasing elemental abundance with increasing condensation temperature, which would result from the stars having accreted planetary debris. Rather, the slopes of linear least...

  17. The Edgeworth-Kuiper debris disk

    CERN Document Server

    Vitense, Christian; Löhne, Torsten

    2010-01-01

    (Abridged) The Edgeworth-Kuiper belt with its presumed dusty debris is a natural reference for extrsolar debris disks. We employ a new algorithm to eliminate the inclination and the distance selection effects in the known TNO populations to derive expected parameters of the "true" EKB. Its estimated mass is M_EKB=0.12 M_earth, which is by a factor of \\sim 15 larger than the mass of the EKB objects detected so far. About a half of the total EKB mass is in classical and resonant objects and another half is in scattered ones. Treating the debiased populations of EKB objects as dust parent bodies, we then "generate" their dust disk with our collisional code. Apart from accurate handling of collisions and direct radiation pressure, we include the Poynting-Robertson (P-R) drag, which cannot be ignored for the EKB dust disk. Outside the classical EKB, the radial profile of the optical depth approximately follows tau \\sim r^-2 which is roughly intermediate between the slope predicted analytically for collision-domina...

  18. The Population of Optically Faint GEO Debris

    Science.gov (United States)

    Seitzer, P.; Barker, E.; Buckalew, B.; Burkhardt, A.; Cowardin, H.; Frith, J.; Kaleida, C.; Lederer, S.; Lee, C.

    2016-09-01

    The 6.5-m Magellan telescope, 'Walter Baade', at the Las Campanas Observatory in Chile has been used for spot surveys of the geosynchronous Earth orbit (GEO) regime to study the population of optically faint GEO debris. The goal is to estimate the population of GEO debris at sizes much smaller than can be studied with 1-meter class telescopes. Despite the small field of view of the Magellan instrument (diameter 0.5-degree), a significant population of objects fainter than R = 19th magnitude has been found with angular rates consistent with circular orbits at GEO. We compare the size of this population with the numbers of GEO objects found at brighter magnitudes by smaller telescopes. The detections have a wide range of characteristics starting with those appearing as short uniform streaks. But there are a substantial number of detections that vary in brightness ("flashers") during the 5-second exposure. The duration of each of these flashes can be extremely brief: sometimes less than half a second. This is characteristic of a rapidly tumbling object with a quite variable projected product of size * albedo. If the albedo is of the order of 0.2, then the largest projected size of these objects is around 10-cm.

  19. Carbon-14 activity of fallout in Araucaria angustifolia annual growth rings, from Arapoti, Parana State, Brazil; Atividade de {sup 14} C do 'fallout' em aneis anuais de crescimento de Araucaria angustifolia, de Arapoti - PR

    Energy Technology Data Exchange (ETDEWEB)

    Lisi, Claudio Sergio; Pessenda, Luiz Carlos Ruiz [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de 14 C; Tomazello Filho, Mario [Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, SP (Brazil). Dept. de Ciencias Florestais. Lab. de Dendrocronologia

    2000-07-01

    During the period of nuclear tests between 1950 and 1960, an input of artificial {sup 14} C (fallout effect) occurred in the natural reservoirs. {sup 14} C determinations in the Northern Hemisphere showed values of {delta}{sup 14} C up to 960 in the year of 1964. To determine the fallout {sup 14} C activity in Brazil, wood samples from Araucaria angustifolia (Bert.) O. Kuntze, Araucariaceae, were collected in Arapoti-PR (24 deg 11{sup S}, 49 deg 58{sup O}). The annual tree rings were selected by dendrochronology. The cellulose was extracted and its {sup 14} C activity determined by liquid scintillation method. The results showed a significant increase of the {delta} {sup 14} C up to 590 in 1965, about 60% higher than the natural activity, gradually decreasing after the end of nuclear tests. These results were correlated with those obtained in the Northen Hemisphere and will be used in the studies of CO{sub 2} mechanisms distribuition to the atmosphere and other natural reservoirs. (author)

  20. Semi-automatic recognition of marine debris on beaches

    Science.gov (United States)

    Ge, Zhenpeng; Shi, Huahong; Mei, Xuefei; Dai, Zhijun; Li, Daoji

    2016-05-01

    An increasing amount of anthropogenic marine debris is pervading the earth’s environmental systems, resulting in an enormous threat to living organisms. Additionally, the large amount of marine debris around the world has been investigated mostly through tedious manual methods. Therefore, we propose the use of a new technique, light detection and ranging (LIDAR), for the semi-automatic recognition of marine debris on a beach because of its substantially more efficient role in comparison with other more laborious methods. Our results revealed that LIDAR should be used for the classification of marine debris into plastic, paper, cloth and metal. Additionally, we reconstructed a 3-dimensional model of different types of debris on a beach with a high validity of debris revivification using LIDAR-based individual separation. These findings demonstrate that the availability of this new technique enables detailed observations to be made of debris on a large beach that was previously not possible. It is strongly suggested that LIDAR could be implemented as an appropriate monitoring tool for marine debris by global researchers and governments.

  1. Predicting Debris-Slide Locations in Northwestern California

    Science.gov (United States)

    Mark E. Reid; Stephen D. Ellen; Dianne L. Brien; Juan de la Fuente; James N. Falls; Billie G. Hicks; Eric C. Johnson

    2007-01-01

    We tested four topographic models for predicting locations of debris-slide sources: 1) slope; 2) proximity to stream; 3) SHALSTAB with "standard" parameters; and 4) debris-slide-prone landforms, which delineates areas similar to "inner gorge" and "headwall swale" using experience-based rules. These approaches were compared in three diverse...

  2. Rapid Assessment of Tree Debris Following Urban Forest Ice Storms

    Science.gov (United States)

    Richard J. Hauer; Angela J. Hauer; Dudley R. Hartel; Jill R. Johnson

    2011-01-01

    This paper presents a rapid assessment method to estimate urban tree debris following an ice storm. Data were collected from 60 communities to quantify tree debris volumes, mostly from public rights-of-way, following ice storms based on community infrastructure, weather parameters, and urban forest structure. Ice thickness, area of a community, and street distance are...

  3. A Support System to Tie Apron Strings to Debris Flow

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Scientists from the Chengdubased CAS Institute of Mountain Hazards and Environment (IMHE) recently worked out a decision-making support system for disaster mitigation on debris fans in mountainous regions.As a domestic vanguard, the system plays a key role in the fight against debris flow and helping to reduce casualties.

  4. Linking effects of anthropogenic debris to ecological impacts.

    Science.gov (United States)

    Browne, Mark Anthony; Underwood, A J; Chapman, M G; Williams, Rob; Thompson, Richard C; van Franeker, Jan A

    2015-05-22

    Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the 'health', feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris.

  5. Launch Vehicle Debris Models and Crew Vehicle Ascent Abort Risk

    Science.gov (United States)

    Gee, Ken; Lawrence, Scott

    2013-01-01

    For manned space launch systems, a reliable abort system is required to reduce the risks associated with a launch vehicle failure during ascent. Understanding the risks associated with failure environments can be achieved through the use of physics-based models of these environments. Debris fields due to destruction of the launch vehicle is one such environment. To better analyze the risk posed by debris, a physics-based model for generating launch vehicle debris catalogs has been developed. The model predicts the mass distribution of the debris field based on formulae developed from analysis of explosions. Imparted velocity distributions are computed using a shock-physics code to model the explosions within the launch vehicle. A comparison of the debris catalog with an existing catalog for the Shuttle external tank show good comparison in the debris characteristics and the predicted debris strike probability. The model is used to analyze the effects of number of debris pieces and velocity distributions on the strike probability and risk.

  6. Linking effects of anthropogenic debris to ecological impacts

    NARCIS (Netherlands)

    Browne, M.A.; Underwood, A.J.; Chapman, M.G.; Williams, R.; Thompson, R.C.; Franeker, van J.A.

    2015-01-01

    Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that li

  7. Linking effects of anthropogenic debris to ecological impacts

    Science.gov (United States)

    Browne, Mark Anthony; Underwood, A. J.; Chapman, M. G.; Williams, Rob; Thompson, Richard C.; van Franeker, Jan A.

    2015-01-01

    Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the ‘health’, feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris. PMID:25904661

  8. 14 CFR 417.225 - Debris risk analysis.

    Science.gov (United States)

    2010-01-01

    ... OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.225 Debris risk analysis. A flight safety analysis must demonstrate that the risk to the public potentially exposed to inert and explosive debris hazards from any one flight of a launch vehicle satisfies the public risk criterion of...

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

    Science.gov (United States)

    Baskaran, M

    2011-05-01

    the discordance is discussed with some key recommendations for future studies. The existing global atmospheric inventory data of (210)Pb is re-evaluated and a 'global curve' for the depositional fluxes of (210)Pb is established. A current global budget for atmospheric (210)Po and (210)Pb is also established. The relative importance of dry fallout of (210)Po and (210)Pb at different latitudes is evaluated. The global values for the deposition velocities of aerosols using (210)Po and (210)Pb are synthesized. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. New simple deposition model based on reassessment of global fallout data 1954 - 1976

    Energy Technology Data Exchange (ETDEWEB)

    Palsson, S.E. [Icelandic Radiation Safety Authority, Reykjavik (Iceland); Bergan, T.D. [Directorate for Civil Protection and Emergency Planning, Toensberg (Norway); Howard, B.J. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster (United Kingdom); Ikaeheimonen, T.K. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland); Isaksson, M. [Univ. of Gothenburg. Dept. of Radiation Physics, Institute of Clinical Sciences, Sahlgren Academy, Gothenburg (Sweden); Nielsen, Sven P. [Technical Univ. of Denmark. DTU Nutech, Roskilde (Denmark); Paatero, J. [Finnish Meteorological Institute. Observation Services, Helsinki (Finland)

    2012-12-15

    Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. This testing is the major cause of distribution of man-made radionuclides over the globe and constitutes a background that needs to be considered when effects of other sources are estimated. The main radionuclides of long term (after the first months) concern are generally assumed to be {sup 137}Cs and {sup 90}Sr. It has been known for a long time that the deposition density of {sup 137}Cs and {sup 90}Sr is approximately proportional to the amount of precipitation. But the use of this proportional relationship raised some questions such as (a) over how large area can it be assumed that the concentration in precipitation is the same at any given time; (b) how does this agree with the observed latitude dependency of deposition density and (c) are the any other parameters that could be of use in a simple model describing global fallout? These issues were amongst those taken up in the NKS-B EcoDoses activity. The preliminary results for {sup 137}Cs and {sup 90}Sr showed for each that the measured concentration had been similar at many European and N-American sites at any given time and that the change with time had been similar. These finding were followed up in a more thorough study in this (DepEstimates) activity. Global data (including the US EML and UK AERE data sets) from 1954 - 1976 for {sup 90}Sr and {sup 137}Cs were analysed testing how well different potential explanatory variables could describe the deposition density. The best fit was obtained by not assuming the traditional proportional relationship, but instead a non-linear power function. The predictions obtained using this new model may not be significantly different from those obtained using the traditional model, when using a limited data set such as from one country as a test in this report showed. But for larger data sets and understanding of underlying processes the new model should be an improvement. (Author)

  11. Understanding Polycyclic Aromatic Hydrocarbon transfers at the catchment scale combining chemical and fallout radionuclides analyses

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  13. Original Misunderstanding

    Science.gov (United States)

    Holtzman, Alexander

    2009-01-01

    Humorist Josh Billings quipped, "About the most originality that any writer can hope to achieve honestly is to steal with good judgment." Billings was harsh in his view of originality, but his critique reveals a tension faced by students every time they write a history paper. Research is the essence of any history paper. Especially in high school,…

  14. Biobjective planning of an active debris removal mission

    Science.gov (United States)

    Madakat, Dalal; Morio, Jérôme; Vanderpooten, Daniel

    2013-03-01

    The growth of the orbital debris population has been a concern to the international space community for several years. Recent studies have shown that the debris environment in Low Earth Orbit (LEO, defined as the region up to 2000 km altitude) has reached a point where the debris population will continue to increase even if all future launches are suspended. As the orbits of these objects often overlap the trajectories of satellites, debris create a potential collision risk. However, several studies show that about 5 objects per year should be removed in order to keep the future LEO environment stable. In this article, we propose a biobjective time dependent traveling salesman problem (BiTDTSP) model for the problem of optimally removing debris and use a branch and bound approach to deal with it.

  15. Constitutive Models for Debris-bearing Ice Layers

    Science.gov (United States)

    Moore, P. L.

    2013-12-01

    Rock debris is incorporated within many glaciers and ice sheets, particularly in basal ice layers and englacial debris bands. Field observations and laboratory experiments have shown that debris inclusions can both strengthen and weaken ice by as much as two orders of magnitude compared to debris-free ice under the same conditions. Nevertheless, models of glacier flow usually neglect any effect of debris-bearing layers. Where debris-bearing ice is present, proper treatment of its deformation could profoundly impact model results. A three-phase mechanical model is presented that reproduces many of the key observations of debris-bearing ice rheology. First order variables in the model are limited to debris concentration, particle size, solute concentration and temperature. At low debris concentrations (less than about 40% by volume), the mixture is treated under the framework of a dispersion-strengthened metal alloy but with a fluidity that is enhanced by premelted water at ice-debris interfaces. While debris strengthens the ice by interfering with the motion of dislocations, thermally-activated detachment can reduce the effect at temperatures close to melting. At these warm temperatures, recovery aided by unfrozen interfacial water acts to weaken the mixture, an effect that is further ehnanced by the presence of solutes at particle surfaces. Whether the debris-bearing ice is stronger or weaker than debris-free ice in the model depends strongly on the specific surface area of the debris and on a parameter that describes the thermal detachment of dislocations. As debris concentrations exceed about 40%, dispersion-strengthened ice flow still governs bulk deformation but the effective viscosity is further increased by enhanced strain rates in the ice "matrix" as the average inter-particle distance declines. At still higher concentrations (greater than about 52% by volume for sand), deformation is primarily frictional. The mixture is thus treated as a dilatant Coulomb

  16. Ice and debris in the fretted terrain, Mars

    Science.gov (United States)

    Lucchitta, B. K.

    1984-01-01

    Viking moderate and high resolution images along the northern highland margin have been monoscopically and stereoscopically examined in order to study the development of fretted terrain. Young debris aprons around mesas and debris in tributary channels create typical fretted morphologies identical to ancient fretted morphologies. This suggests that the debris-apron process operating relatively recently also shaped the fretted terrain of the past. The debris aprons were lubricated by interstitial ice derived from ground ice. Abundant collapse features suggest that ground ice existed and may have flowed in places. The fretting process has been active for a long period and may be active today. The location of debris aprons in two latitudinal belts may be controlled by atmospheric conditions that permit ice in the region to remain in the ground below depths of about one meter and temperatures warm enough for ice to flow.

  17. Methods applied in studies of benthic marine debris.

    Science.gov (United States)

    Spengler, Angela; Costa, Monica F

    2008-02-01

    The ocean floor is one of the main accumulation sites of marine debris. The study of this kind of debris still lags behind that of shorelines. It is necessary to identify the methods used to evaluate this debris and how the results are presented and interpreted. From the available literature on benthic marine debris (26 studies), six sampling methods were registered: bottom trawl net, sonar, submersible, snorkeling, scuba diving and manta tow. The most frequent method used was bottom trawl net, followed by the three methods of diving. The majority of the debris was classified according to their former use and the results usually expressed as items per unity of area. To facilitate comparisons of the contamination levels among sites and regions some standardization requirements are suggested.

  18. On North Pacific circulation and associated marine debris concentration.

    Science.gov (United States)

    Howell, Evan A; Bograd, Steven J; Morishige, Carey; Seki, Michael P; Polovina, Jeffrey J

    2012-01-01

    Marine debris in the oceanic realm is an ecological concern, and many forms of marine debris negatively affect marine life. Previous observations and modeling results suggest that marine debris occurs in greater concentrations within specific regions in the North Pacific Ocean, such as the Subtropical Convergence Zone and eastern and western "Garbage Patches". Here we review the major circulation patterns and oceanographic convergence zones in the North Pacific, and discuss logical mechanisms for regional marine debris concentration, transport, and retention. We also present examples of meso- and large-scale spatial variability in the North Pacific, and discuss their relationship to marine debris concentration. These include mesoscale features such as eddy fields in the Subtropical Frontal Zone and the Kuroshio Extension Recirculation Gyre, and interannual to decadal climate events such as El Niño and the Pacific Decadal Oscillation/North Pacific Gyre Oscillation. Published by Elsevier Ltd.

  19. Cesium, iodine and tritium in NW Pacific waters - a comparison of the Fukushima impact with global fallout

    DEFF Research Database (Denmark)

    Povinec, P. P.; Aoyama, M.; Biddulph, D.;

    2013-01-01

    Radionuclide impact of the Fukushima Dai-ichi nuclear power plant accident on the distribution of radionuclides in seawater of the NW Pacific Ocean is compared with global fallout from atmospheric tests of nuclear weapons. Surface and water column samples collected during the Ka’imikai-o-Kanaloa ......Radionuclide impact of the Fukushima Dai-ichi nuclear power plant accident on the distribution of radionuclides in seawater of the NW Pacific Ocean is compared with global fallout from atmospheric tests of nuclear weapons. Surface and water column samples collected during the Ka...... in the area from 34 to 37° N, and from 142 to 147° E. About 4.6 GBq of 129I was deposited in the NW Pacific Ocean, and 2.4–7 GBq of 129I was directly discharged as liquid wastes into the sea offshore Fukushima. The total amount of 3H released and deposited over the NW Pacific Ocean was estimated to be 0.......1–0.5 PBq. These estimations depend, however, on the evaluation of the total 137Cs activities released as liquid wastes directly into the sea, which should improve when more data are available. Due to a suitable residence time in the ocean, Fukushima-derived radionuclides will provide useful tracers...

  20. Relationship between volcanic ash fallouts and seismic tremor: quantitative assessment of the 2015 eruptive period at Cotopaxi volcano, Ecuador

    Science.gov (United States)

    Bernard, Benjamin; Battaglia, Jean; Proaño, Antonio; Hidalgo, Silvana; Vásconez, Francisco; Hernandez, Stephen; Ruiz, Mario

    2016-11-01

    Understanding the relationships between geophysical signals and volcanic products is critical to improving real-time volcanic hazard assessment. Thanks to high-frequency sampling campaigns of ash fallouts (15 campaigns, 461 samples), the 2015 Cotopaxi eruption is an outstanding candidate for quantitatively comparing the amplitude of seismic tremor with the amount of ash emitted. This eruption emitted a total of 1.2E + 9 kg of ash ( 8.6E + 5 m3) during four distinct phases, with masses ranging from 3.5E + 7 to 7.7E + 8 kg of ash. We compare the ash fallout mass and the corresponding cumulative quadratic median amplitude of the seismic tremor and find excellent correlations when the dataset is divided by eruptive phase. We use scaling factors based on the individual correlations to reconstruct the eruptive process and to extract synthetic Eruption Source Parameters (daily mass of ash, mass eruption rate, and column height) from the seismic records. We hypothesize that the change in scaling factor through time, associated with a decrease in seismic amplitudes compared to ash emissions, is the result of a more efficient fragmentation and transport process. These results open the possibility of feeding numerical models with continuous geophysical data, after adequate calibration, in order to better characterize volcanic hazards during explosive eruptions.