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Sample records for in-channel organic debris

  1. Physical consequences of large organic debris in Pacific Northwest streams.

    Science.gov (United States)

    Frederick J. Swanson; George W. Lienkaemper

    1978-01-01

    Large organic debris in streams controls the distribution of aquatic habitats, the routing of sediment through stream systems, and the stability of streambed and banks. Management activities directly alter debris loading by addition or removal of material and indirectly by increasing the probability of debris torrents and removing standing streamside trees. We propose...

  2. Modeling In-Channel Debris Flow Initiation Pre- and Post-Fire within the San Gabriel Mountains, California

    Science.gov (United States)

    Zdeb, B.; Holo, S.; Palucis, M. C.; Lamb, M. P.

    2016-12-01

    Debris flows are an important geomorphic agent in transporting sediment and eroding rock in mountainous terrain, and they pose significant hazards to people and infrastructure. Debris flows initiated by runoff appear to be a dominant transport process in steep bedrock landscapes, especially where channels fill by dry ravel following wildfire, but our ability to predict where these flows will initiate within the channel network is mainly based on empirical relationships. Here we explore how precipitation rate, precipitation duration, and previously documented decreases in the median grain size following post-fire ravel accumulation affect in-channel debris flow initiation. We utilized ANUGA, a python-based hydrodynamic model, to simulate runoff depths for different storm events for several steep catchments that have recently burned within the San Gabriel Mountains, California. We model peak and average flow depths along the channel network for one-, five-, ten- and 100- year storms from which we calculate the Shield's stress. We compare the modeled Shield's stress to the critical Shield's stress for debris flow initiation by runoff along the entire channel network for both pre- and post-fire conditions. Results allow identification along the channel network where debris flows are most likely to initiate for different storm events, provides a framework for hazard-mitigation efforts, -and demonstrates how sediment transport by debris flows might be included in landscape evolution models.

  3. History, physical effects, and management implications of large organic debris in western Oregon streams.

    Science.gov (United States)

    Frederick Swanson; George W. Lienkaemper; James R. Sedell

    1976-01-01

    Large organic debris has historically been an important element in small mountain streams of the Pacific Northwest. The debris serves to slow the movement of water and inorganic and fine organic matter through the channel. Debris may remain in the channel for decades or longer, and tends to stabilize some sections of a streambed and stream banks while destabilizing...

  4. Assessment of an in-channel redistribution technique for large woody debris management in Locust Creek, Linn County, Missouri

    Science.gov (United States)

    Heimann, David C.

    2017-10-24

    The U.S. Geological Survey, in cooperation with the Missouri Department of Conservation and Missouri Department of Natural Resources, completed a study to assess a mechanical redistribution technique used for the management of large woody debris (LWD) jams in Locust Creek within Pershing State Park and Fountain Grove Conservation Area, Linn County, Missouri. Extensive LWD jams were treated from 1996 to 2009 using a low-impact technique in which LWD from the jams was redistributed to reopen the channel and to mimic the natural geomorphic process of channel migration and adjustment to an obstruction. The scope of the study included the comparison of selected channel geometry characteristics and bed material particle-size distribution in seven LWD treatment reaches with that of adjacent untreated reaches (unaffected by LWD accumulations) of Locust Creek. A comparison of 1996 and 2015 survey cross sections in treated and untreated reaches and photograph documentation were used to assess channel geomorphic change and the stability of redistributed LWD. The physical characteristics of LWD within jams present in the study reach during 2015–16 also were documented.Based on the general lack of differences in channel metrics between treated and untreated reaches, it can be concluded that the mechanical redistribution technique has been an effective treatment of extensive LWD jams in Locust Creek. Channel alterations, including aggradation, streamflow piracy, and diversions, have resulted in temporal and spatial changes in the Locust Creek channel that may affect future applications of the redistribution technique in Pershing State Park. The redistribution technique was used to effectively manage LWD in Locust Creek at a potentially lower financial cost and reduced environmental disturbance than the complete removal of LWD.A comparison of four channel metrics (bankfull cross-sectional area, channel width, streamflow capacity, and width-depth ratio) for individual treatment

  5. Sorption capacity of plastic debris for hydrophobic organic chemicals.

    Science.gov (United States)

    Lee, Hwang; Shim, Won Joon; Kwon, Jung-Hwan

    2014-02-01

    The occurrence of microplastics (MPs) in the ocean is an emerging world-wide concern. Due to high sorption capacity of plastics for hydrophobic organic chemicals (HOCs), sorption may play an important role in the transport processes of HOCs. However, sorption capacity of various plastic materials is rarely documented except in the case of those used for environmental sampling purposes. In this study, we measured partition coefficients between MPs and seawater (KMPsw) for 8 polycyclic aromatic hydrocarbons (PAHs), 4 hexachlorocyclohexanes (HCHs) and 2 chlorinated benzenes (CBs). Three surrogate polymers - polyethylene, polypropylene, and polystyrene - were used as model plastic debris because they are the major components of microplastic debris found. Due to the limited solubility of HOCs in seawater and their long equilibration time, a third-phase partitioning method was used for the determination of KMPsw. First, partition coefficients between polydimethylsiloxane (PDMS) and seawater (KPDMSsw) were measured. For the determination of KMPsw, the distribution of HOCs between PDMS or plastics and solvent mixture (methanol:water=8:2 (v/v)) was determined after apparent equilibrium up to 12 weeks. Plastic debris was prepared in a laboratory by physical crushing; the median longest dimension was 320-440 μm. Partition coefficients between polyethylene and seawater obtained using the third-phase equilibrium method agreed well with experimental partition coefficients between low-density polyethylene and water in the literature. The values of KMPsw were generally in the order of polystyrene, polyethylene, and polypropylene for most of the chemicals tested. The ranges of log KMPsw were 2.04-7.87, 2.18-7.00, and 2.63-7.52 for polyethylene, polypropylene, and polystyrene, respectively. The partition coefficients of plastic debris can be as high as other frequently used partition coefficients, such as 1-octanol-water partition coefficients (Kow) and log KMPsw showed good linear

  6. Styrofoam Debris as a Source of Hazardous Additives for Marine Organisms.

    Science.gov (United States)

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

    2016-05-17

    There is growing concern over plastic debris and their fragments as a carrier for hazardous substances in marine ecosystem. The present study was conducted to provide field evidence for the transfer of plastic-associated chemicals to marine organisms. Hexabromocyclododecanes (HBCDs), brominated flame retardants, were recently detected in expanded polystyrene (styrofoam) marine debris. We hypothesized that if styrofoam debris acts as a source of the additives in the marine environment, organisms inhabiting such debris might be directly influenced by them. Here we investigated the characteristics of HBCD accumulation by mussels inhabiting styrofoam. For comparison, mussels inhabiting different substrates, such as high-density polyethylene (HDPE), metal, and rock, were also studied. The high HBCD levels up to 5160 ng/g lipid weight and the γ-HBCD dominated isomeric profiles in mussels inhabiting styrofoam strongly supports the transfer of HBCDs from styrofoam substrate to mussels. Furthermore, microsized styrofoam particles were identified inside mussels, probably originating from their substrates.

  7. Managing organic debris for forest health: Reconciling fire hazard, bark beetles, wildlife, and forest nutrition needs

    Science.gov (United States)

    Chris Schnepf; Russell T. Graham; Sandy Kegley; Theresa B. Jain

    2009-01-01

    Forest organic debris includes tree limbs, boles (trunks), needles, leaves, snags, and other dead organic materials. It ranges in amount and composition depending on a forest's history, tree species, condition, and age. In the Inland Northwest (Idaho, western Montana, eastern Oregon, and eastern Washington) there is a lot of discussion and concern about removing...

  8. Woody debris

    Science.gov (United States)

    Donna B. Scheungrab; Carl C. Trettin; Russ Lea; Martin F. Jurgensen

    2000-01-01

    Woody debris can be defined as any dead, woody plant material, including logs, branches, standing dead trees, and root wads. Woody debris is an important part of forest and stream ecosystems because it has a role in carbon budgets and nutrient cycling, is a source of energy for aquatic ecosystems, provides habitat for terrestrial and aquatic organisms, and contributes...

  9. Potential transfer of organic pollutants from littoral plastics debris to the marine environment.

    Science.gov (United States)

    León, Víctor M; García, Inés; González, Emilia; Samper, Raquel; Fernández-González, Verónica; Muniategui-Lorenzo, Soledad

    2018-02-05

    Plastic polymers act as passive samplers in air system and concentrate hydrophobic organic contaminants by sorption or specific interactions, which can be transported to other systems such as the marine environment. In this study plastic debris was sampled in the surrounding area of a Mediterranean lagoon in order to determine the concentration of persistent and emerging organic contaminants. More specifically, desorption of 91 regulated and emerging organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorinated pesticides, current-use pesticides, personal care products, other pesticides and plastic additives) was characterized for the first 24 h from different polymers to seawater and the remaining content of these contaminants was also extracted by ultrasonic extraction with methanol. All samples were analyzed by Stir Bar Sorptive Extraction coupled to GC/MS. A significant fraction of sorbed contaminants in polymers was desorbed in the first 24 h, particularly for triazines and organophosphorus pesticides due to their lower hydrophobicity than other considered analytes. The remaining contaminants contained in plastics can be also transferred to seawater, sediments or biota. Considering 24 h desorbed fraction plus the remaining methanol extracted fraction, the highest transfer levels corresponded to personal care products, plastic additives, current-use pesticides and PAHs. This is the first study to show the relevance of the transport of organic contaminants on plastic debris from littoral areas to the marine environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Organic micropollutants in marine plastics debris from the open ocean and remote and urban beaches.

    Science.gov (United States)

    Hirai, Hisashi; Takada, Hideshige; Ogata, Yuko; Yamashita, Rei; Mizukawa, Kaoruko; Saha, Mahua; Kwan, Charita; Moore, Charles; Gray, Holly; Laursen, Duane; Zettler, Erik R; Farrington, John W; Reddy, Christopher M; Peacock, Emily E; Ward, Marc W

    2011-08-01

    To understand the spatial variation in concentrations and compositions of organic micropollutants in marine plastic debris and their sources, we analyzed plastic fragments (∼10 mm) from the open ocean and from remote and urban beaches. Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dichloro-diphenyl-trichloroethane and its metabolites (DDTs), polybrominated diphenyl ethers (PBDEs), alkylphenols and bisphenol A were detected in the fragments at concentrations from 1 to 10,000 ng/g. Concentrations showed large piece-to-piece variability. Hydrophobic organic compounds such as PCBs and PAHs were sorbed from seawater to the plastic fragments. PCBs are most probably derived from legacy pollution. PAHs showed a petrogenic signature, suggesting the sorption of PAHs from oil slicks. Nonylphenol, bisphenol A, and PBDEs came mainly from additives and were detected at high concentrations in some fragments both from remote and urban beaches and the open ocean. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Seaweeds and plastic debris can influence the survival of faecal indicator organisms in beach environments.

    Science.gov (United States)

    Quilliam, Richard S; Jamieson, Julie; Oliver, David M

    2014-07-15

    The revised Bathing Water Directive (rBWD) introduces more stringent standards for microbial water quality and promotes more pro-active management of the beach environment through the production of a bathing water profile (BWP). The aim of this study was to determine whether living seaweeds in the littoral zone are colonised by faecal indicator organisms (FIOs), and to quantify the survival dynamics of waterborne Escherichia coli in microcosms containing senescing seaweeds. Living seaweed (Fucus spiralis) was not associated with FIO colonisation, although could be providing a protected environment in the underlying sand. Senescing seaweeds enhanced waterborne E. coli survival compared to plastic debris, with the brown seaweed Laminaria saccharina facilitating greater E. coli persistence than either Chondrus crispus or Ulva lactuca. This has important implications for FIO survival on bathing beaches as the majority of beach-cast biomass is composed of brown seaweeds, which could support significant levels of FIOs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Persistent organic pollutants in plastic marine debris found on beaches in San Diego, California.

    Science.gov (United States)

    Van, Almira; Rochman, Chelsea M; Flores, Elisa M; Hill, Kish L; Vargas, Erica; Vargas, Serena A; Hoh, Euhna

    2012-01-01

    Plastic debris were collected from eight beaches around San Diego County, California. Debris collected include: pre-production pellets and post-consumer plastics including fragments, polystyrene (PS) foam, and rubber. A total of n = 2453 pieces were collected ranging from plastic pieces were separated by type, location, and appearance and analyzed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and its breakdown products, and chlordanes. PAH concentrations ranged from 30 ng g(-1) to 1900 ng g(-1), PCBs from non-detect to 47 ng g(-1), chlordanes from 1.8 ng g(-1) to 60 ng g(-1), and DDTs from non-detect to 76 ng g(-1). Consistently higher PAH concentrations found in PS foam samples (300-1900 ng g(-1)) led us to examine unexposed PS foam packaging materials and PS virgin pellets. Unexposed PS foam contained higher concentrations of PAHs (240-1700 ng g(-1)) than PS virgin pellets (12-15 ng g(-1)), suggesting that PAHs may be produced during manufacturing. Temporal trends of debris were investigated at one site, Ocean Beach, where storm events and beach maintenance were found to be important variables influencing debris present at a given time. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Factors controlling the fluvial export of large woody debris, and its contribution to organic carbon budgets at watershed scales

    Science.gov (United States)

    Seo, Jung Il; Nakamura, Futoshi; Nakano, Daisuke; Ichiyanagi, Hidetaka; Chun, Kun Woo

    2008-04-01

    The fluvial export of large woody debris (LWD) was monitored in 131 reservoirs throughout Japan. Published data on the fluvial export of dissolved and particulate organic carbon were used to estimate the contributions of LWD in carbon budgets. Of all variables tested, watershed area was most important in explaining LWD carbon (LWDC) export, followed by annual precipitation. LWDC export per unit area was relatively high in small watersheds, highest in intermediate-sized watersheds, and decreased in large watersheds. In small watersheds, a large proportion of LWD retained on narrow valley floors may fragment or decay and eventually be exported in forms other than LWD. In intermediate-sized watersheds, LWD supplied from upstream and recruited by bank erosion is consistently transported downstream. In large watersheds, LWD recruitment is limited and LWD transported from upstream is stored on large floodplains. These differences in LWD recruitment, retention and transport in watersheds of different sizes lead to the proportion of LWDC in organic carbon exports to be maximum in intermediate-sized watersheds and decline rapidly in large watersheds.

  14. Transport, retention, and ecological significance of woody debris within a large ephemeral river

    Science.gov (United States)

    Jacobson, P.J.; Jacobson, K.M.; Angermeier, P.L.; Cherry, D.S.

    1999-01-01

    The spatiotemporal patterns and ecological significance of the retention of coarse particulate organic matter and large woody debris have been intensively studied in perennial rivers and streams but are virtually unknown in ephemeral systems. We examined the influence of 2 features characteristic of ephemeral systems, downstream hydrologic decay and in-channel tree growth, on the distribution, transport, and retention of woody debris following a flood having a ~2.6-y recurrence interval in the ephemeral Kuiseb River in southwestern Africa. A total of 2105 pieces of wood were painted at 8 sites along the river channel to measure retention patterns. The flood had a peak discharge of 159 m3/s at the upper end of the study area, decaying to <1 m3/s by 200 km downstream. Downstream export of wood from marking sites totaled 59.5% (n = 1253). Transport distances ranged from 1 to 124 km, and 34.8% (n = 436) of the exported wood was recovered. Marked wood retained within marking sites was significantly longer than exported wood (p < 0.001, t-test). Once in transport, there was little correlation between wood length and distance traveled (r = 0.11, correlation analysis, n = 369). Length influenced the site of retention; material retained on debris piles was significantly longer than that stranded on channel sediments (p < 0.001, t-test). In-channel growth of Faidherbia trees significantly influenced wood retention; 83.7% of marked wood not moved by the flood was associated with debris piles on Faidherbia trees. Similarly, 65% of the exported wood retained within downstream debris piles was associated with Faidherbia trees. In contrast to many perennial systems, we observed a general increase in wood retention downstream, peaking in the river's lower reaches in response to hydrologic decay. Debris piles induced sediment deposition and the formation of in-channel islands. Following flood recession, debris piles and their associated sediments provided moist, organic

  15. Quantitation of persistent organic pollutants adsorbed on plastic debris from the Northern Pacific Gyre's "eastern garbage patch".

    Science.gov (United States)

    Rios, Lorena M; Jones, Patrick R; Moore, Charles; Narayan, Urja V

    2010-12-01

    Floating marine plastic debris was found to function as solid-phase extraction media, adsorbing and concentrating pollutants out of the water column. Plastic debris was collected in the North Pacific Gyre, extracted, and analyzed for 36 individual PCB congeners, 17 organochlorine pesticides, and 16 EPA priority PAHs. Over 50% contained PCBs, 40% contained pesticides, and nearly 80% contained PAHs. The PAHs included 2, 3 and 4 ring congeners. The PCBs were primarily CB-11, 28, 44, 52, 66, and 101. The pesticides detected were primarily p,p-DDTs and its metabolite, o,p-DDD, as well as BHC (a,b,g and d). The concentrations of pollutants found ranged from a few ppb to thousands of ppb. The types of PCBs and PAHs found were similar to those found in marine sediments. However, these plastic particles were mostly polyethylene which is resistant to degradation and although functioning similarly to sediments in accumulating pollutants, these had remained on or near the ocean surface. Particles collected included intact plastic items as well as many pieces less than 5 mm in size.

  16. The impact of debris on marine life.

    Science.gov (United States)

    Gall, S C; Thompson, R C

    2015-03-15

    Marine debris is listed among the major perceived threats to biodiversity, and is cause for particular concern due to its abundance, durability and persistence in the marine environment. An extensive literature search reviewed the current state of knowledge on the effects of marine debris on marine organisms. 340 original publications reported encounters between organisms and marine debris and 693 species. Plastic debris accounted for 92% of encounters between debris and individuals. Numerous direct and indirect consequences were recorded, with the potential for sublethal effects of ingestion an area of considerable uncertainty and concern. Comparison to the IUCN Red List highlighted that at least 17% of species affected by entanglement and ingestion were listed as threatened or near threatened. Hence where marine debris combines with other anthropogenic stressors it may affect populations, trophic interactions and assemblages. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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

  18. Validation of ATR FT-IR to identify polymers of plastic marine debris, including those ingested by marine organisms.

    Science.gov (United States)

    Jung, Melissa R; Horgen, F David; Orski, Sara V; Rodriguez C, Viviana; Beers, Kathryn L; Balazs, George H; Jones, T Todd; Work, Thierry M; Brignac, Kayla C; Royer, Sarah-Jeanne; Hyrenbach, K David; Jensen, Brenda A; Lynch, Jennifer M

    2018-02-01

    Polymer identification of plastic marine debris can help identify its sources, degradation, and fate. We optimized and validated a fast, simple, and accessible technique, attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR), to identify polymers contained in plastic ingested by sea turtles. Spectra of consumer good items with known resin identification codes #1-6 and several #7 plastics were compared to standard and raw manufactured polymers. High temperature size exclusion chromatography measurements confirmed ATR FT-IR could differentiate these polymers. High-density (HDPE) and low-density polyethylene (LDPE) discrimination is challenging but a clear step-by-step guide is provided that identified 78% of ingested PE samples. The optimal cleaning methods consisted of wiping ingested pieces with water or cutting. Of 828 ingested plastics pieces from 50 Pacific sea turtles, 96% were identified by ATR FT-IR as HDPE, LDPE, unknown PE, polypropylene (PP), PE and PP mixtures, polystyrene, polyvinyl chloride, and nylon. Published by Elsevier Ltd.

  19. Flow-sediment-large woody debris interplay: Introducing an appropriately scaled laboratory experiment

    Science.gov (United States)

    Friedrich, H.; Spreitzer, G.; Tunnicliffe, J. F.

    2017-12-01

    The morphology of steep (>0.01 m/m) forested streams is governed not only by water-sediment interplay, but also by accumulations of coarse and fine organic debris. In this project we look at the jamming dynamics (formation, persistence and hydraulic feedbacks) of large woody debris with the help of scaled laboratory experiments. In New Zealand, the recruitment of wood from both natural tree-fall and forest harvesting has led to obstruction of culverts, bridges and other river constrictions. Understanding the dynamics of jam formation and persistence is important for harvest practice guidelines, management of sediment accumulation, as well as establishing impacts to habitat and infrastructure. In this study, we provide the context of our work, present our experimental setup for studying the complex flow-sediment-wood interactions and present some initial results. In our experimental setup, we varied feed rates of sediment and organic fine material in order to establish concentration thresholds for jam formation, and development of sediment retention capacity upstream of the jam. Large woody debris accumulation is studied for different blocking scenarios, and the effect on sediment transport is measured. Sediment quantities and changes in channel bed morphology upstream of the critical cross section are evaluated, together with resulting backwater effects, and associated energy losses. In the long term, our results will inform our understanding of the processes that take place from the mobilization of woody debris to accumulation.

  20. Persistent organic pollutants in fat of three species of Pacific pelagic longline caught sea turtles: Accumulation in relation to ingested plastic marine debris.

    Science.gov (United States)

    Clukey, Katharine E; Lepczyk, Christopher A; Balazs, George H; Work, Thierry M; Li, Qing X; Bachman, Melannie J; Lynch, Jennifer M

    2018-01-01

    In addition to eating contaminated prey, sea turtles may be exposed to persistent organic pollutants (POPs) from ingesting plastic debris that has absorbed these chemicals. Given the limited knowledge about POPs in pelagic sea turtles and how plastic ingestion influences POP exposure, our objectives were to: 1) provide baseline contaminant levels of three species of pelagic Pacific sea turtles; and 2) assess trends of contaminant levels in relation to species, sex, length, body condition and capture location. In addition, we hypothesized that if ingesting plastic is a significant source of POP exposure, then the amount of ingested plastic may be correlated to POP concentrations accumulated in fat. To address our objectives we compared POP concentrations in fat samples to previously described amounts of ingested plastic from the same turtles. Fat samples from 25 Pacific pelagic sea turtles [2 loggerhead (Caretta caretta), 6 green (Chelonia mydas) and 17 olive ridley (Lepidochelys olivacea) turtles] were analyzed for 81 polychlorinated biphenyls (PCBs), 20 organochlorine pesticides, and 35 brominated flame-retardants. The olive ridley and loggerhead turtles had higher ΣDDTs (dichlorodiphenyltrichloroethane and metabolites) than ΣPCBs, at a ratio similar to biota measured in the South China Sea and southern California. Green turtles had a ratio close to 1:1. These pelagic turtles had lower POP levels than previously reported in nearshore turtles. POP concentrations were unrelated to the amounts of ingested plastic in olive ridleys, suggesting that their exposure to POPs is mainly through prey. In green turtles, concentrations of ΣPCBs were positively correlated with the number of plastic pieces ingested, but these findings were confounded by covariance with body condition index (BCI). Green turtles with a higher BCI had eaten more plastic and also had higher POPs. Taken together, our findings suggest that sea turtles accumulate most POPs through their prey rather

  1. Persistent organic pollutants in fat of three species of Pacific pelagic longline caught sea turtles: Accumulation in relation to ingested plastic marine debris

    Science.gov (United States)

    Clukey, Katharine; Lepczyk, Christopher A.; Balazs, George H.; Work, Thierry M.; Li, Qing X.; Bachman, Melanie J.; Lynch, Jennifer M.

    2017-01-01

    In addition to eating contaminated prey, sea turtles may be exposed to persistent organic pollutants (POPs) from ingesting plastic debris that has absorbed these chemicals. Given the limited knowledge about POPs in pelagic sea turtles and how plastic ingestion influences POP exposure, our objectives were to: 1) provide baseline contaminant levels of three species of pelagic Pacific sea turtles; and 2) assess trends of contaminant levels in relation to species, sex, length, body condition and capture location. In addition, we hypothesized that if ingesting plastic is a significant source of POP exposure, then the amount of ingested plastic may be correlated to POP concentrations accumulated in fat. To address our objectives we compared POP concentrations in fat samples to previously described amounts of ingested plastic from the same turtles. Fat samples from 25 Pacific pelagic sea turtles [2 loggerhead (Caretta caretta), 6 green (Chelonia mydas) and 17 olive ridley (Lepidochelys olivacea) turtles] were analyzed for 81 polychlorinated biphenyls (PCBs), 20 organochlorine pesticides, and 35 brominated flame-retardants. The olive ridley and loggerhead turtles had higher ΣDDTs (dichlorodiphenyltrichloroethane and metabolites) than ΣPCBs, at a ratio similar to biota measured in the South China Sea and southern California. Green turtles had a ratio close to 1:1. These pelagic turtles had lower POP levels than previously reported in nearshore turtles. POP concentrations were unrelated to the amounts of ingested plastic in olive ridleys, suggesting that their exposure to POPs is mainly through prey. In green turtles, concentrations of ΣPCBs were positively correlated with the number of plastic pieces ingested, but these findings were confounded by covariance with body condition index (BCI). Green turtles with a higher BCI had eaten more plastic and also had higher POPs. Taken together, our findings suggest that sea turtles accumulate most POPs through their prey rather

  2. Orbital debris: a technical assessment

    National Research Council Canada - National Science Library

    National Research Council Staff; Commission on Engineering and Technical Systems; Division on Engineering and Physical Sciences; National Research Council; National Academy of Sciences

    ..., and other debris created as a byproduct of space operations. Orbital Debris examines the methods we can use to characterize orbital debris, estimates the magnitude of the debris population, and assesses the hazard that this population poses to spacecraft...

  3. Long-term field measurement of sorption of organic contaminants to five types of plastic pellets: implications for plastic marine debris.

    Science.gov (United States)

    Rochman, Chelsea M; Hoh, Eunha; Hentschel, Brian T; Kaye, Shawn

    2013-02-05

    Concerns regarding marine plastic pollution and its affinity for chemical pollutants led us to quantify relationships between different types of mass-produced plastic and organic contaminants in an urban bay. At five locations in San Diego Bay, CA, we measured sorption of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) throughout a 12-month period to the five most common types of mass-produced plastic: polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), and polypropylene (PP). During this long-term field experiment, sorption rates and concentrations of PCBs and PAHs varied significantly among plastic types and among locations. Our data suggest that for PAHs and PCBs, PET and PVC reach equilibrium in the marine environment much faster than HDPE, LDPE, and PP. Most importantly, concentrations of PAHs and PCBs sorbed to HDPE, LDPE, and PP were consistently much greater than concentrations sorbed to PET and PVC. These data imply that products made from HDPE, LDPE, and PP pose a greater risk than products made from PET and PVC of concentrating these hazardous chemicals onto fragmented plastic debris ingested by marine animals.

  4. Protein analysis in dissolved organic matter: What proteins from organic debris, soil leachate and surface water can tell us - a perspective

    Directory of Open Access Journals (Sweden)

    W. X. Schulze

    2005-01-01

    Full Text Available Mass spectrometry based analysis of proteins is widely used to study cellular processes in model organisms. However, it has not yet routinely been applied in environmental research. Based on observations that protein can readily be detected as a component of dissolved organic matter (DOM, this article gives an example about the possible use of protein analysis in ecology and environmental sciences focusing on different terrestrial ecosystems. At this stage, there are two areas of interest: (1 the identification of phylogenetic groups contributing to the environmental protein pool, and (2 identification of the organismic origin of specific enzymes that are important for ecosystem processes. In this paper, mass spectrometric protein analysis was applied to identify proteins from decomposing plant material and DOM of soil leachates and surface water samples derived from different environments. It is concluded, that mass spectrometric protein analysis is capable of distinguishing phylogenetic origin of proteins from litter protein extracts, leachates of different soil horizons, and from various sources of terrestrial surface water. Current limitation is imposed by the limited knowledge of complete genomes of soil organisms. The protein analysis allows to relate protein presence to biogeochemical processes, and to identify the source organisms for specific active enzymes. Further applications, such as in pollution research are conceivable. In summary, the analysis of proteins opens a new area of research between the fields of microbiology and biogeochemistry.

  5. Semi-automatic recognition of marine debris on beaches

    OpenAIRE

    Ge, Zhenpeng; Shi, Huahong; Mei, Xuefei; Dai, Zhijun; Li, Daoji

    2016-01-01

    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 ...

  6. 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.

  7. Loopy, Floppy and Fragmented: Debris Characteristics Matter

    Science.gov (United States)

    Parrish, J.; Burgess, H. K.

    2016-02-01

    Marine debris is a world-wide problem threatening the health and safety of marine organisms, ecosystems, and humans. Recent and ongoing research shows that risk of harm is not associated with identity, but rather with a set of specific character states, where the character state space intersection is defined by the organism of interest. For example, intersections of material, color, rigidity and size predict the likelihood of an object being ingested: plastic, clear-white, floppy objects risks to sea turtles whereas yellow-red, rigid objects risks to albatrosses. A character state space approach allows prioritization of prevention and removal of marine debris informed by risk assessments for species of interest by comparing species ranges with spatio-temporal hotspots of all debris with characteristics known to be associated with increased risk of harm, regardless of identity. With this in mind, the Coastal Observation and Seabird Survey Team (COASST) developed and tested a 20 character data collection approach to quantifying the diversity and abundance of marine debris found on beaches. Development resulted in meta-analysis of the literature and expert opinion eliciting harmful character state space. Testing included data collection on inter-rater reliability and accuracy, where the latter included 75 participants quantifying marine debris characteristics on monthly surveys of 30 beaches along the Washington and Oregon coastlines over the past year. Pilot work indicates that characters must be simply and operationally defined, states must be listed, and examples must be provided for color states. Complex characters (e.g., windage, shape) are not replicable across multiple data collectors. Although data collection takes longer than other marine debris surveys for a given amount of debris and area surveyed, volunteer rapidity and accuracy improved within 3-5 surveys. Initial feedback indicated that volunteers were willing to continue collecting data as long as they

  8. 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

  9. Disaster Debris Recovery Database - Landfills

    Data.gov (United States)

    U.S. Environmental Protection Agency — The US EPA Disaster Debris Recovery Database (DDRD) promotes the proper recovery, recycling, and disposal of disaster debris for emergency responders at the federal,...

  10. Disaster Debris Recovery Database - Recovery

    Data.gov (United States)

    U.S. Environmental Protection Agency — The US EPA Disaster Debris Recovery Database (DDRD) promotes the proper recovery, recycling, and disposal of disaster debris for emergency responders at the federal,...

  11. Benthic plastic debris in marine and fresh water environments.

    Science.gov (United States)

    Corcoran, Patricia L

    2015-08-01

    This review provides a discussion of the published literature concerning benthic plastic debris in ocean, sea, lake, estuary and river bottoms throughout the world. Although numerous investigations of shoreline, surface and near-surface plastic debris provide important information on plastic types, distribution, accumulation, and degradation, studies of submerged plastic debris have been sporadic in the past and have become more prominent only recently. The distribution of benthic debris is controlled mainly by combinations of urban proximity and its association with fishing-related activities, geomorphology, hydrological conditions, and river input. High density plastics, biofouled products, polymers with mineral fillers or adsorbed minerals, and plastic-metal composites all have the potential to sink. Once deposited on the bottoms of water basins and channels, plastics are shielded from UV light, thus slowing the degradation process significantly. Investigations of the interactions between benthic plastic debris and bottom-dwelling organisms will help shed light on the potential dangers of submerged plastic litter.

  12. Semi-automatic recognition of marine debris on beaches.

    Science.gov (United States)

    Ge, Zhenpeng; Shi, Huahong; Mei, Xuefei; Dai, Zhijun; Li, Daoji

    2016-05-09

    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.

  13. Space debris- ECSL Study

    Science.gov (United States)

    Lafferranderie, G.

    2002-01-01

    Despite several attempts and despite the worldwide recognition of the need of attacking it, the space debris legal issues has not been put in the agenda as a separate issue on the agenda of the COPUOS Legal Subcommittee. However for the first time, mention will appear in 2002 but only under item 5 of the Legal Subcommittee: report of activities of international organisations, here the European Centre for Space Law (ECSL). ECSL report will describe the method followed, a questionnaire widely distributed to interested persons and on a personal basis. The questionnaire tries to identify the basic concerns. From the responses received and from also analysis of positions expressed in various colloquia, articles, etc. some directions could be drawn up: do we need a "legal definition" of space debris? For which purposes? Are we in a situation fro presenting now such a legal definition able to cope with the technical evolution of the space object? Which type of legal or technical description "instrument" will be the most appropriate? Etc. One particular question is emerging: the basis of the liability for damages caused in outer space. The author wish is simply to draw the attention on concrete, immediate concerns while identifying also simple ways able to offer a framework to deal with the legal impacts coming from space debris issue. I have envisioned two other subjects that I have abandoned: .

  14. Analysis of the Mobilization of Debris Flows

    Science.gov (United States)

    1974-10-01

    c O 9 • •s • •rl O o • 43 « l| •H P0 >. cn IM IW n >M cd C IM o • Tt •H •o » •O -H O B u • 60 .H c •H 0 • Cd r-H SS el 5 co oe en a o...California (Matthes, 1930, p. 108-109). One source area, between the Three Brothers and El Capltan, Is described as being in a recess: "... only 1 1...nearly general deformation as the masses move into channels, and finally to the plastico -vlscous type of flow recognized in channelized debris flows

  15. Persistent marine debris

    International Nuclear Information System (INIS)

    Levy, E.M.

    1992-01-01

    In this paper the distribution of persistent marine debris, adrift on world oceans and stranded on beaches globally, is reviewed and related to the known inputs and transport by the major surface currents. Since naturally occurring processes eventually degrade petroleum in the environment, international measures to reduce the inputs have been largely successful in alleviating oil pollution on a global, if not on a local, scale. Many plastics, however, are so resistant to natural degradation that merely controlling inputs will be insufficient, and more drastic and costly measures will be needed to cope with the emerging global problem posed by these materials

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

    Science.gov (United States)

    Ryan, Peter G; Moore, Charles J; van Franeker, Jan A; Moloney, Coleen L

    2009-07-27

    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 by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally.

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

    Science.gov (United States)

    Ryan, Peter G.; Moore, Charles J.; van Franeker, Jan A.; Moloney, Coleen 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 by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally. PMID:19528052

  18. 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

  19. Remote Sensing of Plastic Debris

    Science.gov (United States)

    Garaba, S. P.; Dierssen, H. M.

    2016-02-01

    Plastic debris is becoming a nuisance in the environment and as a result there has been a dire need to synoptically detect and quantify them in the ocean and on land. We investigate the possible utility of spectral information determined from hand held, airborne and satellite remote sensing tools in the detection and identification polymer source of plastic debris. Sampled debris will be compared to our derived spectral library of typical raw polymer sources found at sea and in household waste. Additional work will be to determine ways to estimate the abundance of plastic debris in target areas. Implications of successful remote detection, tracking and quantification of plastic debris will be towards validating field observations over large areas and at repeated time intervals both on land and at sea.

  20. Modeling the transport and accumulation floating debris generated by the 11 March 2011 Tohoku tsunami.

    Science.gov (United States)

    Lebreton, Laurent C-M; Borrero, Jose C

    2013-01-15

    A global ocean circulation model is coupled to a particle-tracking model to simulate the transport of floating debris washed into the North Pacific Ocean by the Tohoku tsunami. A release scenario for the tsunami debris is based on coastal population and measured tsunami runup. Archived 2011/2012 hindcast current data is used to model the transport of debris since the tsunami, while data from 2008 to 2012 is used to investigate the distribution of debris on timescales up to 4years. The vast amount of debris pushed into ocean likely represents thousands of years worth of 'normal' litter flux from Japan's urbanized coastline. This is important since a significant fraction of the debris will be comprised of plastics, some of which will degrade into tiny particles and be consumed by marine organisms, thereby allowing adsorbed organic pollutants to enter our food supply in quantities much higher than present. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. 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

  2. JSC Orbital Debris Website Description

    Science.gov (United States)

    Johnson, Nicholas L.

    2006-01-01

    Purpose: The website provides information about the NASA Orbital Debris Program Office at JSC, which is the lead NASA center for orbital debris research. It is recognized world-wide for its leadership in addressing orbital debris issues. The NASA Orbital Debris Program Office has taken the international lead in conducting measurements of the environment and in developing the technical consensus for adopting mitigation measures to protect users of the orbital environment. Work at the center continues with developing an improved understanding of the orbital debris environment and measures that can be taken to control its growth. Major Contents: Orbital Debris research is divided into the following five broad efforts. Each area of research contains specific information as follows: 1) Modeling - NASA scientists continue to develop and upgrade orbital debris models to describe and characterize the current and future debris environment. Evolutionary and engineering models are described in detail. Downloadable items include a document in PDF format and executable software. 2) Measurements - Measurements of near-Earth orbital debris are accomplished by conducting ground-based and space-based observations of the orbital debris environment. The data from these sources provide validation of the environment models and identify the presence of new sources. Radar, optical and surface examinations are described. External links to related topics are provided. 3) Protection - Orbital debris protection involves conducting hypervelocity impact measurements to assess the risk presented by orbital debris to operating spacecraft and developing new materials and new designs to provide better protection from the environment with less weight penalty. The data from this work provides the link between the environment defined by the models and the risk presented by that environment to operating spacecraft and provides recommendations on design and operations procedures to reduce the risk as

  3. 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. .

  4. 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.

  5. TMI-2 core debris analysis

    International Nuclear Information System (INIS)

    Cook, B.A.; Carlson, E.R.

    1985-01-01

    One of the ongoing examination tasks for the damaged TMI-2 reactor is analysis of samples of debris obtained from the debris bed presently at the top of the core. This paper summarizes the results reported in the TMI-2 Core Debris Grab Sample Examination and Analysis Report, which will be available early in 1986. The sampling and analysis procedures are presented, and information is provided on the key results as they relate to the present core condition, peak temperatures during the transient, temperature history, chemical interactions, and core relocation. The results are then summarized

  6. 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 analysis...

  7. 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.

  8. Plastic debris in the coastal environment: The invincible threat? Abundance of buried plastic debris on Malaysian beaches.

    Science.gov (United States)

    Fauziah, S H; Liyana, I A; Agamuthu, P

    2015-09-01

    Studies on marine debris have gained worldwide attention since many types of debris have found their way into the food chain of higher organisms. Thus, it is crucial that more focus is given to this area in order to curb contaminations in sea food. This study was conducted to quantify plastic debris buried in sand at selected beaches in Malaysia. Marine debris was identified according to size range and distribution, and this information was related to preventive actions to improve marine waste issues. For the purpose of this study, comparison of plastic waste abundance between a recreational beach and fish-landing beaches was also carried out, since the different beach types represent different activities that produce debris. Six beaches along the Malaysian coastline were selected for this study. The plastic types in this study were related to the functions of the beach. While recreational beaches have abundant quantities of plastic film, foamed plastic including polystyrene, and plastic fragment, fish-landing beaches accumulated line and foamed plastic. A total of 2542 pieces (265.30 g m(-2)) of small plastic debris were collected from all six beaches, with the highest number from Kuala Terengganu, at 879 items m(-2) on Seberang Takir Beach, followed by Batu Burok Beach with 780 items m(-2). Findings from studies of Malaysian beaches have provided a clearer understanding of the distribution of plastic debris. This demonstrates that commitments and actions, such as practices of the 'reduce, reuse, recycle' (3R) approach, supporting public awareness programmes and beach clean-up activities, are essential in order to reduce and prevent plastic debris pollution. © The Author(s) 2015.

  9. Debris flows: Experiments and modelling

    Science.gov (United States)

    Turnbull, Barbara; Bowman, Elisabeth T.; McElwaine, Jim N.

    2015-01-01

    Debris flows and debris avalanches are complex, gravity-driven currents of rock, water and sediments that can be highly mobile. This combination of component materials leads to a rich morphology and unusual dynamics, exhibiting features of both granular materials and viscous gravity currents. Although extreme events such as those at Kolka Karmadon in North Ossetia (2002) [1] and Huascarán (1970) [2] strongly motivate us to understand how such high levels of mobility can occur, smaller events are ubiquitous and capable of endangering infrastructure and life, requiring mitigation. Recent progress in modelling debris flows has seen the development of multiphase models that can start to provide clues of the origins of the unique phenomenology of debris flows. However, the spatial and temporal variations that debris flows exhibit make this task challenging and laboratory experiments, where boundary and initial conditions can be controlled and reproduced, are crucial both to validate models and to inspire new modelling approaches. This paper discusses recent laboratory experiments on debris flows and the state of the art in numerical models.

  10. The physics of debris flows

    Science.gov (United States)

    Iverson, R.M.

    1997-01-01

    Recent advances in theory and experimentation motivate a thorough reassessment of the physics of debris flows. Analyses of flows of dry, granular solids and solid-fluid mixtures provide a foundation for a comprehensive debris flow theory, and experiments provide data that reveal the strengths and limitations of theoretical models. Both debris flow materials and dry granular materials can sustain shear stresses while remaining static; both can deform in a slow, tranquil mode characterized by enduring, frictional grain contacts; and both can flow in a more rapid, agitated mode characterized by brief, inelastic grain collisions. In debris flows, however, pore fluid that is highly viscous and nearly incompressible, composed of water with suspended silt and clay, can strongly mediate intergranular friction and collisions. Grain friction, grain collisions, and viscous fluid flow may transfer significant momentum simultaneously. Both the vibrational kinetic energy of solid grains (measured by a quantity termed the granular temperature) and the pressure of the intervening pore fluid facilitate motion of grains past one another, thereby enhancing debris flow mobility. Granular temperature arises from conversion of flow translational energy to grain vibrational energy, a process that depends on shear rates, grain properties, boundary conditions, and the ambient fluid viscosity and pressure. Pore fluid pressures that exceed static equilibrium pressures result from local or global debris contraction. Like larger, natural debris flows, experimental debris flows of ???10 m3 of poorly sorted, water-saturated sediment invariably move as an unsteady surge or series of surges. Measurements at the base of experimental flows show that coarse-grained surge fronts have little or no pore fluid pressure. In contrast, finer-grained, thoroughly saturated debris behind surge fronts is nearly liquefied by high pore pressure, which persists owing to the great compressibility and moderate

  11. The ecological impacts of marine debris: unraveling the demonstrated evidence from what is perceived.

    Science.gov (United States)

    Rochman, Chelsea M; Browne, Mark Anthony; Underwood, A J; van Franeker, Jan A; Thompson, Richard C; Amaral-Zettler, Linda A

    2016-02-01

    Anthropogenic debris contaminates marine habitats globally, leading to several perceived ecological impacts. Here, we critically and systematically review the literature regarding impacts of debris from several scientific fields to understand the weight of evidence regarding the ecological impacts of marine debris. We quantified perceived and demonstrated impacts across several levels of biological organization that make up the ecosystem and found 366 perceived threats of debris across all levels. Two hundred and ninety-six of these perceived threats were tested, 83% of which were demonstrated. The majority (82%) of demonstrated impacts were due to plastic, relative to other materials (e.g., metals, glass) and largely (89%) at suborganismal levels (e.g., molecular, cellular, tissue). The remaining impacts, demonstrated at higher levels of organization (i.e., death to individual organisms, changes in assemblages), were largely due to plastic marine debris (> 1 mm; e.g., rope, straws, and fragments). Thus, we show evidence of ecological impacts from marine debris, but conclude that the quantity and quality of research requires improvement to allow the risk of ecological impacts of marine debris to be determined with precision. Still, our systematic review suggests that sufficient evidence exists for decision makers to begin to mitigate problematic plastic debris now, to avoid risk of irreversible harm.

  12. 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.

  13. Disaster Debris Recovery Database - Landfills

    Science.gov (United States)

    The US EPA Region 5 Disaster Debris Recovery Database includes public datasets of over 6,000 composting facilities, demolition contractors, transfer stations, landfills and recycling facilities for construction and demolition materials, electronics, household hazardous waste, metals, tires, and vehicles in the states of Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Ohio, Pennsylvania, South Dakota, West Virginia and Wisconsin.In this update, facilities in the 7 states that border the EPA Region 5 states were added to assist interstate disaster debris management. Also, the datasets for composters, construction and demolition recyclers, demolition contractors, and metals recyclers were verified and source information added for each record using these sources: AGC, Biocycle, BMRA, CDRA, ISRI, NDA, USCC, FEMA Debris Removal Contractor Registry, EPA Facility Registry System, and State and local listings.

  14. Participatory Sensing Marine Debris: Current Trends and Future Opportunities

    Science.gov (United States)

    Jambeck, J.; Johnsen, K.

    2016-02-01

    The monitoring of litter and debris is challenging at the global scale because of spatial and temporal variability, disconnected local organizations and the use of paper and pen for documentation. The Marine Debris Tracker mobile app and citizen science program allows for the collection of global standardized data at a scale, speed and efficiency that was not previously possible. The app itself also serves as an outreach and education tool, creating an engaged participatory sensing instrument. This instrument is characterized by several aspects including range and frequency, accuracy and precision, accessibility, measurement dimensions, participant performance, and statistical analysis. Also, important to Marine Debris Tracker is open data and transparency. A web portal provides data that users have logged allowing immediate feedback to users and additional education opportunities. The engagement of users through a top tracker competition and social media keeps participants interested in the Marine Debris Tracker community. Over half a million items have been tracked globally, and maps provide both global and local distribution of data. The Marine Debris Tracker community and dataset continues to grow daily. We will present current usage and engagement, participatory sensing data distributions, choropleth maps of areas of active tracking, and discuss future technologies and platforms to expand data collection and conduct statistical analysis.

  15. Mechanics of debris flows and rock avalanches: Chapter 43

    Science.gov (United States)

    Iverson, Richard M.; Fernando, Harindra Joseph

    2012-01-01

    Debris flows are geophysical phenomena intermediate in character between rock avalanches and flash floods. They commonly originate as water-laden landslides on steep slopes and transform into liquefied masses of fragmented rock, muddy water, and entrained organic matter that disgorge from canyons onto valley floors. Typically including 50%–70% solid grains by volume, attaining speeds >10 m/s, and ranging in size up to ∼109 m3, debris flows can denude mountainsides, inundate floodplains, and devastate people and property (Figure 43.1). Notable recent debris-flow disasters resulted in more than 20,000 fatalities in Armero, Colombia, in 1985 and in Vargas state, Venezuela, in 1999.

  16. Space Debris Elimination (SpaDE)

    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...

  17. The ecological impacts of marine debris

    NARCIS (Netherlands)

    Rochman, Chelsea M.; Browne, Mark Anthony; Underwood, A.J.; Franeker, Van Jan A.; Thompson, Richard C.; Amaral-Zettler, Linda A.

    2016-01-01

    Anthropogenic debris contaminates marine habitats globally, leading to several perceived ecological impacts. Here, we critically and systematically review the literature regarding impacts of debris from several scientific fields to understand the weight of evidence regarding the ecological

  18. 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...

  19. 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.

  20. CDOT rapid debris removal research project.

    Science.gov (United States)

    2014-07-01

    Highway debris represents a traffic safety problem that requires a prompt response from state or local transportation : agencies. The most common practice for debris removal currently is for agency personnel to leave their vehicles and : remove the d...

  1. Recent space debris related topics in Japan

    Science.gov (United States)

    Kibe, S.; Kawamoto, S.; Gilardi, G.

    This paper introduces recent space debris related activities in Japan. As for the ground based observation, the progress of the 1 m optical telescope construction at the Bisei Space Guard Center is to be reported as well as technology development such as the automated debris detection and attitude estimation techniques from optical image data. Next, activities on the hypervelocity acceleration technology are to be mentioned. Tokyo Institute of Technology team succeeded to launch a projectile of 0.6 g at 8.2 km/s using their Two-/Three- Stage Light Gas Gun, which is believed to be the world record for TSLGGs. In addition, National Aerospace Laboratory has been continuing their efforts to develop the Inhibited Conical Shaped Charge Launcher and is currently investigating the effects of high internal energy and irregular shape of the projectile. Based on the projectile density measurement method newly proposed by them, comparison with the other CSC system than NAL's one is to be shown. Finally, introduced is the progress of research activities on the active removal system for post mission spacecraft. Based on the technological foundation acquired in the ETS-VII experiment, NAL and NASDA are pursuing the possibility of active removal of system level large objects from the densely populated orbit, which contains a lot of technological challenges such as angular motion estimation using only image data, angular momentum dissipation, electro-dynamic tether as a highly efficient thruster and remote and autonomous robot operation. Also shortly introduced is domestic dis cussion on implementation of debris related activities in Japan's new space development organization to be founded in January 2004.

  2. Orbital Debris and Future Environment Remediation

    Science.gov (United States)

    Liou, Jer-Chyi

    2011-01-01

    This slide presentation is an overview of the historical and current orbital debris environment. Included is information about: Projected growth of the future debris population, The need for active debris removal (ADR), A grand challenge for the 21st century and The forward path

  3. Emissions from the burning of vegetative debris in air curtain destructors.

    Science.gov (United States)

    Miller, C Andrew; Lemieux, Paul M

    2007-08-01

    Although air curtain destructors (ACDs) have been used for quite some time to dispose of vegetative debris, relatively little in-depth testing has been conducted to quantify emissions of pollutants other than CO and particulate matter. As part of an effort to prepare for possible use of ACDs to dispose of the enormous volumes of debris generated by Hurricanes Katrina and Rita, the literature on ACD emissions was reviewed to identify potential environmental issues associated with ACD disposal of construction and demolition (C&D) debris. Although no data have been published on emissions from C&D debris combustion in an ACD, a few studies provided information on emissions from the combustion of vegetative debris. These studies are reviewed, and the results compared with studies of open burning of biomass. Combustion of vegetative debris in ACD units results in significantly lower emissions of particulate matter and CO per unit of mass of debris compared with open pile burning. The available data are not sufficient to make general estimates regarding emissions of organic or metal compounds. The highly transient nature of the ACD combustion process, a minimal degree of operational control, and significant variability in debris properties make accurate prediction of ACD emissions impossible in general. Results of scoping tests conducted in preparation for possible in-depth emissions tests demonstrate the challenges associated with sampling ACD emissions and highlight the transient nature of the process. The environmental impacts of widespread use of ACDs for disposal of vegetative debris and their potential use to reduce the volume of C&D debris in future disaster response scenarios remain a considerable gap in understanding the risks associated with debris disposal options.

  4. Observed Marine Debris in the Pacific Ocean 00e2?? Victoria to Maui 2012

    Science.gov (United States)

    Location and descriptions of marine debris observed by the Sailing Vessel (S/V) Family Affair yacht during the Victoria, British Columbia to Maui, Hawaii Yacht Race in July 2012. These observations are organized according to the following map layers: Family Affairs Observations, Fleet Debris Levels, Return Vessels Special Reports, Roll Call Debris Data-Race, Special Report Debris-Race, Vessel Specific Observations, and Return Vessel Specific Levels Observations.The March, 2011 tsunami that affected northern Japan washed enormous amounts of debris out to sea. While most of this debris sank quickly out at sea, much remains on the surface and by ocean current and wind is working its way across the Pacific Ocean. In early days, the U.S. National Oceanic and Atmospheric Administration (NOAA) could track the debris slick by satellite, but by early 2012, the debris had become too dispersed to track. News stories have reported containers with motorcycles on Haida Gwaii, whole fishing boats in Alaska, and sections of concrete dock in Oregon. Recent reports are about the struggles of local governments to deal with cleaning up and disposing of flotsam washing up on local beaches.

  5. Estimates of marine debris accumulation on beaches are strongly affected by the temporal scale of sampling.

    Science.gov (United States)

    Smith, Stephen D A; Markic, Ana

    2013-01-01

    Marine debris is a global issue with impacts on marine organisms, ecological processes, aesthetics and economies. Consequently, there is increasing interest in quantifying the scale of the problem. Accumulation rates of debris on beaches have been advocated as a useful proxy for at-sea debris loads. However, here we show that past studies may have vastly underestimated the quantity of available debris because sampling was too infrequent. Our study of debris on a small beach in eastern Australia indicates that estimated daily accumulation rates decrease rapidly with increasing intervals between surveys, and the quantity of available debris is underestimated by 50% after only 3 days and by an order of magnitude after 1 month. As few past studies report sampling frequencies of less than a month, estimates of the scale of the marine debris problem need to be critically re-examined and scaled-up accordingly. These results reinforce similar, recent work advocating daily sampling as a standard approach for accurate quantification of available debris in coastal habitats. We outline an alternative approach whereby site-specific accumulation models are generated to correct bias when daily sampling is impractical.

  6. Colisional Cloud Debris and Propelled Evasive Maneuvers

    Science.gov (United States)

    Ferreira, L. S.; Jesus, A. D. C.; Carvalho, T. C. F.; Sousa, R. R.

    2017-10-01

    Space debris clouds exist at various altitudes in the environment outside the Earth. Fragmentation of debris and/or collision between the debris of a cloud increases the amount of debris, producing smaller debris. This event also increases significantly the chances of collision with operational vehicles in orbit. In this work we study clouds of debris that are close to a spacecraft in relation to its distance from the center of the Earth. The results show several layers of colliding debris depending on their size over time of evasive maneuvers of the vehicle. In addition, we have tested such maneuvers for propulsion systems with a linear and exponential mass variation model. The results show that the linear propulsion system is more efficient.

  7. 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

  8. Behavior of explosion debris clouds

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    In the normal course of events the behavior of debris clouds created by explosions will be of little concern to the atomic energy industry. However, two situations, one of them actual and one postulated, exist where the rise and spread of explosion clouds can affect site operations. The actual occurrence would be the detonation of nuclear weapons and the resultant release and transport of radioactive debris across the various atomic energy installations. Although the activity of the diffusing cloud is not of biological concern, it may still be sufficiently above background to play havoc with the normal readings of sensitive monitoring instruments. If it were not known that these anomalous readings resulted from explosion debris, considerable time and expense might be required for on-site testing and tracing. Fortunately it is usually possible, with the use of meteorological data and forecasts, to predict when individual sites are affected by nuclear weapon debris effects. The formation rise, and diffusion of weapon clouds will be discussed. The explosion of an atomic reactor is the postulated situation. It is common practice in reactor hazard analysis to assume a combination of circumstances which might result in a nuclear incident with a release of material to the atmosphere. It is not within the scope of this report to examine the manifold plausibilities that might lead to an explosion or the possible methods of release of gaseous and/or particulates from such an occurrence. However, if the information of a cloud is assumed and some idea of its energy content is obtainable, estimates of the cloud behavior in the atmosphere can be made

  9. Space Debris and Observational Astronomy

    Science.gov (United States)

    Seitzer, Patrick

    2018-01-01

    Since the launch of Sputnik 1 in 1957, astronomers have faced an increasing number of artificial objects contaminating their images of the night sky. Currently almost 17000 objects larger than 10 cm are tracked and have current orbits in the public catalog. Active missions are only a small fraction of these objects. Most are inactive satellites, rocket bodies, and fragments of larger objects: all space debris. Several mega-constellations are planned which will increase this number by 20% or more in low Earth orbit (LEO). In terms of observational astronomy, this population of Earth orbiting objects has three implications: 1) the number of streaks and glints from spacecraft will only increase. There are some practical steps that can be taken to minimize the number of such streaks and glints in astronomical imaging data. 2) The risk to damage to orbiting astronomical telescopes will only increase, particularly those in LEO. 3) If you are working on a plan for an orbiting telescope project, then there are specific steps that must be taken to minimize space debris generation during the mission lifetime, and actions to safely dispose of the spacecraft at end of mission to prevent it from becoming space debris and a risk to other missions. These steps may involve sacrifices to mission performance and lifetime, but are essential in today's orbital environment.

  10. Size distribution of stranded small plastic debris on the coast of Guangdong, South China.

    Science.gov (United States)

    Fok, Lincoln; Cheung, Pui Kwan; Tang, Guangda; Li, Wai Chin

    2017-01-01

    Beach environments are known to be conducive to fragmentation of plastic debris, and highly fragmented plastic particles can interact with smaller organisms. Even through stranded plastic debris may not interact directly with marine organisms, backwash processes may transport this debris back to coastal waters, where it may affect a wide range of marine life at different trophic levels. This study analysed the size distribution of stranded plastic debris (plastic debris by abundance and 71% by weight, indicating that the plastic debris on these coastal beaches was highly fragmented and the majority of the plastic masses belonged to the microplastic size range. The observed size distributions of PS foams and fragments are believed to result from continued fragmentation. Previous studies found that the residence time of beached debris was less than one year on average, and no sign of plastic accumulation with depth in beach sediment was observed. Therefore, coastal beaches may represent a reservoir of highly fragmented and degraded microplastics that may be mobilised and returned to the sea during storm events. Further research on the dynamics and longevity of microplastics on beaches will help reveal the mass balance of microplastics on the shoreline and determine whether shorelines are sinks or sources of microplastics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Space Shuttle Solid Rocket Booster Debris Assessment

    Science.gov (United States)

    Kendall, Kristin; Kanner, Howard; Yu, Weiping

    2006-01-01

    The Space Shuttle Columbia Accident revealed a fundamental problem of the Space Shuttle Program regarding debris. Prior to the tragedy, the Space Shuttle requirement stated that no debris should be liberated that would jeopardize the flight crew and/or mission success. When the accident investigation determined that a large piece of foam debris was the primary cause of the loss of the shuttle and crew, it became apparent that the risk and scope of - damage that could be caused by certain types of debris, especially - ice and foam, were not fully understood. There was no clear understanding of the materials that could become debris, the path the debris might take during flight, the structures the debris might impact or the damage the impact might cause. In addition to supporting the primary NASA and USA goal of returning the Space Shuttle to flight by understanding the SRB debris environment and capability to withstand that environment, the SRB debris assessment project was divided into four primary tasks that were required to be completed to support the RTF goal. These tasks were (1) debris environment definition, (2) impact testing, (3) model correlation and (4) hardware evaluation. Additionally, the project aligned with USA's corporate goals of safety, customer satisfaction, professional development and fiscal accountability.

  12. 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

  13. Evaluating tsunami hazards from debris flows

    Science.gov (United States)

    Watts, P.; Walder, J.S.; ,

    2003-01-01

    Debris flows that enter water bodies may have significant kinetic energy, some of which is transferred to water motion or waves that can impact shorelines and structures. The associated hazards depend on the location of the affected area relative to the point at which the debris flow enters the water. Three distinct regions (splash zone, near field, and far field) may be identified. Experiments demonstrate that characteristics of the near field water wave, which is the only coherent wave to emerge from the splash zone, depend primarily on debris flow volume, debris flow submerged time of motion, and water depth at the point where debris flow motion stops. Near field wave characteristics commonly may be used as & proxy source for computational tsunami propagation. This result is used to assess hazards associated with potential debris flows entering a reservoir in the northwestern USA. ?? 2003 Millpress,.

  14. Marine debris occurrence and treatment: A review

    OpenAIRE

    Iñiguez, María Esperanza; Conesa, Juan A.; Fullana, Andres

    2016-01-01

    Marine debris produces a wide variety of negative environmental, economic, safety, health and cultural impacts. Most marine litter has a very low decomposition rate (as plastics, which are the most abundant type of marine debris), leading to a gradual, but significant accumulation in the coastal and marine environment. Along that time, marine debris is a significant source of chemical contaminants to the marine environment. Once extracted from the water, incineration is the method most widely...

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

    OpenAIRE

    Gil, Michael A.; Pfaller, Joseph B.

    2016-01-01

    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 T?hoku tsunami, to examine the relationship between rafting community diversity and both habitat area and stalked barnacle (Lepas spp.) abundance. For sessile taxa richness, we ob...

  16. Microbiological analysis of debris from STS-42 IML-1 by direct plating of rinse waters

    Science.gov (United States)

    Smithers, G. A.

    1992-01-01

    Microbial analysis of air filter debris from the Spacelab International Microgravity Laboratory-1 (IML-1) mission was performed via direct plating of rinse waters on a battery of selective and nonselective nutrient agars. Microbial isolates were identified using Minitek and Biolog technologies. Twenty-four types of bacteria were recovered and classified; a similar number of fungal types was observed, but these were not identified. This procedure can provide information about the proportions of organism types present at the time of debris collection.

  17. DebriSat Pre Preshot Laboratory Analyses

    Science.gov (United States)

    2015-03-27

    panels consisting of fiberglass (E-glass, #1,2,4,5), stainless steel mesh (#3) and Kevlar (#6,7). In contrast to the DebriSat and Debris-LV impact...shield supplied by NASA which consisted of seven bumper panels consisting of fiberglass (E-glass, #1,2,4,5), stainless steel mesh (#3) and Kevlar (#6,7...bumper panels of fiberglass, stainless steel mesh and Kevlar . – No “soft catch “ panels were installed (unlike Debris-LV and DebriSat). – Test conducted

  18. Small satellites and space debris issues

    Science.gov (United States)

    Yakovlev, M.; Kulik, S.; Agapov, V.

    2001-10-01

    The objective of this report is the analysis of the tendencies in designing of small satellites (SS) and the effect of small satellites on space debris population. It is shown that SS to include nano- and pico-satellites should be considered as a particularly dangerous source of space debris when elaborating international standards and legal documents concerning the space debris problem, in particular "International Space Debris Mitigation Standard". These issues are in accordance with the IADC goals in its main activity areas and should be carefully considered within the IADC framework.

  19. Debris Thermal Hydraulics Modeling of QUENCH Experiments

    International Nuclear Information System (INIS)

    Kisselev, Arcadi E.; Kobelev, Gennadii V.; Strizhov, Valerii F.; Vasiliev, Alexander D.

    2006-01-01

    Porous debris formation and behavior in QUENCH experiments (QUENCH-02, QUENCH-03) plays a considerable role and its adequate modeling is important for thermal analysis. This work is aimed to the development of a numerical module which is able to model thermal hydraulics and heat transfer phenomena occurring during the high-temperature stage of severe accident with the formation of debris region and molten pool. The original approach for debris evolution is developed from classical principles using a set of parameters including debris porosity; average particle diameter; temperatures and mass fractions of solid, liquid and gas phases; specific interface areas between different phases; effective thermal conductivity of each phase, including radiative heat conductivity; mass and energy fluxes through the interfaces. The debris model is based on the system of continuity, momentum and energy conservation equations, which consider the dynamics of volume-averaged velocities and temperatures of fluid, solid and gaseous phases of porous debris. The different mechanisms of debris formation are considered, including degradation of fuel rods according to temperature criteria, taking into consideration some correlations between rod layers thicknesses; degradation of rod layer structure due to thermal expansion of melted materials inside intact rod cladding; debris formation due to sharp temperature drop of previously melted material due to reflood; and transition to debris of material from elements lying above. The porous debris model was implemented to best estimate numerical code RATEG/SVECHA/HEFEST developed for modeling thermal hydraulics and severe accident phenomena in a reactor. The model is used for calculation of QUENCH experiments. The results obtained by the model are compared to experimental data concerning different aspects of thermal behavior: thermal hydraulics of porous debris, radiative heat transfer in a porous medium, the generalized melting and refreezing

  20. The Fabulous Four Debris Disks

    Science.gov (United States)

    Werner, Michael; Stapelfeldt, Karl

    2004-09-01

    This program is a comprehensive study of the four bright debris disks that were spatially resolved by IRAS: Beta Pictoris, Epsilon Eridani, Fomalhaut, and Vega. All SIRTF instruments and observing modes will be used. The program has three major objectives: (1) Study of the disk spatial structure from MIPS and IRAC imaging; (2) Study of the dust grain composition using the IRS and MIPS SED mode; and (3) companion searches using IRAC. The data from this program should lead to a detailed understanding of these four systems, and will provide a foundation for understanding all of the debris disks to be studied with SIRTF. Images and spectra will be compared with models for disk structure and dust properties. Dynamical features indicative of substellar companions' effects on the disks will be searched for. This program will require supporting observations of PSF stars, some of which have been included explicitly. In the majority of cases, the spectral observations require a preferred orientation to align the slits along the disk position angles. Detector saturation issues are still being worked for this program, and will lead to AOR modifications in subsequent submissions. The results from this program will be analyzed collaboratively by the IRAC, IRS, and MIPS teams and by general GTOs Jura and Werner.

  1. Formation Flying Guidance for Space Debris Observation, Manipulation and Capture

    Science.gov (United States)

    Peters, Thomas V.

    This article provides a brief overview of the space debris population, debris attitude dynamics, technologies for debris removal, followed by a more in-depth discussion of robotic arm based capture of debris. Guidance aspects of active debris removal missions are discussed. Mission phases for active debris removal missions are rendezvous, inspection, attitude synchronization and capture and de-tumbling. The need for attitude synchronization is driven by recent observations of Envisat which exhibits a fairly high rotation rate.

  2. Debris mitigation methods for bridge piers.

    Science.gov (United States)

    2012-06-01

    Debris accumulation on bridge piers is an on-going national problem that can obstruct the waterway openings at bridges and result in significant erosion of stream banks and scour at abutments and piers. In some cases, the accumulation of debris can a...

  3. 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.

  4. Development of the Space Debris Sensor

    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 2017. The SDS is the first flight demonstration of the Debris Resistive/Acoustic Grid Orbital NASA-Navy Sensor (DRAGONS) developed and matured by the NASA 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 micron to 500 micron in size. This paper describes the SDS features 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.

  5. Accumulation and fragmentation of plastic debris in global environments.

    Science.gov (United States)

    Barnes, David K A; Galgani, Francois; Thompson, Richard C; Barlaz, Morton

    2009-07-27

    One of the most ubiquitous and long-lasting recent changes to the surface of our planet is the accumulation and fragmentation of plastics. Within just a few decades since mass production of plastic products commenced in the 1950s, plastic debris has accumulated in terrestrial environments, in the open ocean, on shorelines of even the most remote islands and in the deep sea. Annual clean-up operations, costing millions of pounds sterling, are now organized in many countries and on every continent. Here we document global plastics production and the accumulation of plastic waste. While plastics typically constitute approximately 10 per cent of discarded waste, they represent a much greater proportion of the debris accumulating on shorelines. Mega- and macro-plastics have accumulated in the highest densities in the Northern Hemisphere, adjacent to urban centres, in enclosed seas and at water convergences (fronts). We report lower densities on remote island shores, on the continental shelf seabed and the lowest densities (but still a documented presence) in the deep sea and Southern Ocean. The longevity of plastic is estimated to be hundreds to thousands of years, but is likely to be far longer in deep sea and non-surface polar environments. Plastic debris poses considerable threat by choking and starving wildlife, distributing non-native and potentially harmful organisms, absorbing toxic chemicals and degrading to micro-plastics that may subsequently be ingested. Well-established annual surveys on coasts and at sea have shown that trends in mega- and macro-plastic accumulation rates are no longer uniformly increasing: rather stable, increasing and decreasing trends have all been reported. The average size of plastic particles in the environment seems to be decreasing, and the abundance and global distribution of micro-plastic fragments have increased over the last few decades. However, the environmental consequences of such microscopic debris are still poorly

  6. Debris flow impact on mitigation barriers: a new method for particle-fluid-structure interactions

    Science.gov (United States)

    Marchelli, Maddalena; Pirulli, Marina; Pudasaini, Shiva P.

    2016-04-01

    Channelized debris-flows are a type of mass movements that involve water-charged, predominantly coarse-grained inorganic and organic material flowing rapidly down steep confined pre-existing channels (Van Dine, 1985). Due to their rapid movements and destructive power, structural mitigation measures have become an integral part of counter measures against these phenomena, to mitigate and prevent damages resulting from debris-flow impact on urbanized areas. In particular, debris barriers and storage basins, with some form of debris-straining structures incorporated into the barrier constructed across the path of a debris-flow, have a dual role to play: (1) to stimulate deposition by presenting a physical obstruction against flow, and (2) to guarantee that during normal conditions stream water and bedload can pass through the structure; while, during and after an extreme event, the water that is in the flow and some of the fine-grained sediment can escape. A new method to investigate the dynamic interactions between the flowing mass and the debris barrier is presented, with particular emphasis on the effect of the barrier in controlling the water and sediment content of the escaping mass. This aspect is achieved by implementing a new mechanical model into an enhanced two-phase dynamical mass flow model (Pudasaini, 2012), in which solid particles mixture and viscous fluid are taken into account. The complex mechanical model is defined as a function of the energy lost during impact, the physical and geometrical properties of the debris barrier, separate but strongly interacting dynamics of boulder and fluid flows during the impact, particle concentration distribution, and the slope characteristics. The particle-filtering-process results in a large variation in the rheological properties of the fluid-dominated escaping mass, including the substantial reduction in the bulk density, and the inertial forces of the debris-flows. Consequently, the destructive power and run

  7. 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].

  8. [Systemic spread of wear debris--an in-vivo study].

    Science.gov (United States)

    Burian, B; Wimmer, M A; Kunze, J; Sprecher, C M; Pennekamp, P H; von Engelhardt, L V; Diedrich, O; Kraft, C N

    2006-01-01

    The aim of this study was to elucidate whether there is a systemic spread of wear debris from peripherally applied stainless steel and titanium particles into the blood and subsequently to parenchymatous organs. Furthermore, we report on histological findings at the implantation site. In Syrian Gold hamsters we implanted 2 mm3 wear debris of stainless steel and titanium into the dorsal skin fold chamber. Over a period of 2 weeks we took blood samples and afterwards explanted the implant area, the heart, lung, liver and spleen. One half of the organs and the implant area were used for histological analysis. The other half of the organs and the blood samples were analysed by optical emission spectrometer with inductively coupled plasma and graphite furnace atomic absorption spectrophotometry for their contents of chromium, nickel and titanium. In the group with titanium particles, histological analysis of the implant site showed moderate phagocyted wear in granulocytes but no other pathological findings. Animals treated with stainless steel wear debris had a massive inflammatory reaction, in some cases leading to necrosis. The analysis of the blood and one half of the organs showed increased levels of chromium and, already 24 hours after implantation, raised values for nickel. The result of the hamsters treated with titanium showed significantly elevated levels of titanium ions in the organs, but not in the blood samples. Histology of the organs did not reveal pathological findings. In this study we could show a massive inflammatory reaction for stainless steel wear debris in contrast to titanium wear debris at the implantation site. The elevated blood levels of chromium and increased values of other metals in the organs suggest the haematogenic distribution of ions from the peripherally implanted wear debris.

  9. A global map of supraglacial debris cover and recent debris area changes

    Science.gov (United States)

    Herreid, S.; Pellicciotti, F.

    2017-12-01

    The extent of supraglacial rock debris is both a first order indicator of the rock flux within a glacier system and an important term in glacier mass balance models where debris cover modulates the energy fluxes that reach the buried glacier ice surface. To date, no global debris cover inventory is available and most global models of glacier change do not include the effect of debris cover on mass balance. We have used Landsat data and glacier outlines from the Randolph Glacier Inventory v6.0 and PROMICE (Programme for Monitoring of the Greenland Ice Sheet) to generate a modern-date global inventory of debris cover at a spatial resolution of 30 m. For select locations around the Earth with high concentrations of glacier ice and suitable historical imagery, we have derived changes in debris-covered area. We present the heterogeneous pattern of debris cover on Earth which is the integrated signal from hundreds of years of rock debris accumulation and transportation through each glacier system. We further resolve this debris history by presenting recent changes in debris-covered area over the satellite era. Preliminary results from Southeast Alaska, USA, Baffin Island, Canada, Southeast Greenland, and the Eastern Himalaya, China all show an increase in debris-covered area over the past tens of years with heterogeneous rates of increase. This study provides a greater geomorphological understanding of glaciers, their surrounding environment and the flux of supraglacial debris at timescales of both hundreds and tens of years. These data also serve as an input dataset and/or an indicator pointing to locations where debris cover needs to be considered in glacier melt models.

  10. Nuclear-powered space debris sweeper

    Science.gov (United States)

    Metzger, John D.; Leclaire, Rene J., Jr.; Howe, Steven D.; Burgin, Karen C.

    1989-01-01

    Future spacecraft design will be affected by collisions with man-made debris orbiting the earth. Most of this orbital space debris comes from spent rocket stages. It is projected that the source of future debris will be the result of fragmentation of large objects through hypervelocity collisions. Orbiting spacecraft will have to be protected from hypervelocity debris in orbit. The options are to armor the spacecraft, resulting in increased mass, or actively removing the debris from orbit. An active space debris sweeper is described which will utilize momentum transfer to the debris through laser-induced ablation to alter its orbital parameters to reduce orbital lifetime with eventual entry into the earth's atmosphere where it will burn. The paper describes the concept, estimates the amount of velocity change (Delta V) that can be imparted to an object through laser-induced ablation, and investigates the use of a neutral particle beam for the momentum transfer. The space sweeper concept could also be extended to provide a collision avoidance system for the space station and satellites, or could be used for collision protection during interplanetary travel.

  11. 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.

  12. Apparatus for controlling nuclear core debris

    International Nuclear Information System (INIS)

    Jones, R.D.

    1978-01-01

    Disclosed is an apparatus for containing, cooling, and dispersing reactor debris assumed to flow from the core area in the unlikely event of an accident causing core meltdown. The apparatus includes a plurality of horizontally disposed vertically spaced plates, having depressions to contain debris in controlled amounts, and a plurality of holes therein which provide natural circulation cooling and a path for debris to continue flowing downward to the plate beneath. The uppermost plates may also include generally vertical sections which form annular-like flow areas which assist the natural circulation cooling

  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. Distribution and assessment of marine debris in the deep Tyrrhenian Sea (NW Mediterranean Sea, Italy).

    Science.gov (United States)

    Angiolillo, Michela; Lorenzo, Bianca di; Farcomeni, Alessio; Bo, Marzia; Bavestrello, Giorgio; Santangelo, Giovanni; Cau, Angelo; Mastascusa, Vincenza; Cau, Alessandro; Sacco, Flavio; Canese, Simonepietro

    2015-03-15

    Marine debris is a recognized global ecological concern. Little is known about the extent of the problem in the Mediterranean Sea regarding litter distribution and its influence on deep rocky habitats. A quantitative assessment of debris present in the deep seafloor (30-300 m depth) was carried out in 26 areas off the coast of three Italian regions in the Tyrrhenian Sea, using a Remotely Operated Vehicle (ROV). The dominant type of debris (89%) was represented by fishing gears, mainly lines, while plastic objects were recorded only occasionally. Abundant quantities of gears were found on rocky banks in Sicily and Campania (0.09-0.12 debris m(-2)), proving intense fishing activity. Fifty-four percent of the recorded debris directly impacted benthic organisms, primarily gorgonians, followed by black corals and sponges. This work provides a first insight on the impact of marine debris in Mediterranean deep ecosystems and a valuable baseline for future comparisons. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Influence of Instruments Used in Root Canal Preparation on Amount of Apically Extruded Debris.

    Science.gov (United States)

    Karataş, Ertuğrul; Ersoy, İbrahim; Gündüz, Hicran Ateş; Uygun, Ahmet Demirhan; Kol, Elif; Çakıcı, Fatih

    2016-08-01

    The aim of the present study was to compare the effects of ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne instruments on the amount of apically extruded debris. Eighty mandibular premolar teeth with straight root canals were selected and assigned to four groups (n = 20). The root canals were instrumented using ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne systems. Eppendorf tubes containing apically extruded debris were weighed three times, and mean values were calculated. The net mass of the extruded debris was calculated by subtracting the initial mass from the final mass. The groups were compared using one-way analysis of variance and Tukey's post hoc tests at a significance level of P extruded less debris than the PTU group, and the WOG group extruded less debris than the WO group (P < 0.05). All the instrumentation systems tested in the present study were associated with apical extrusion of debris. Copyright © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  17. Development of debris-resistant bottom end piece

    International Nuclear Information System (INIS)

    Sohn, Dong Seong; Lee, Jae Kyung; Hwang, Dae Hyun; Yim, Jung Sik; Song, Kee Nam; Oh, Dong Seok; Im, Hyun Tae

    1993-01-01

    Debris-related fuel failures has been identified to be one of the major causes of fuel failures recently occured in nuclear power plants. In order to reduce the possibility of debris-related fuel failures, it is necessary to prevent the debris from reaching to fuel rods. In this regard, it is important to develop Debris-Resistant Bottom End Piece. (Author)

  18. Microbial activity in debris-rich basal ice; adaption to sub-zero, saline conditions

    Science.gov (United States)

    Montross, S. N.; Skidmore, M. L.; Christner, B. C.; Griggs, R.; Tison, J.; Sowers, T. A.

    2011-12-01

    Polycrystalline ice in glaciers and ice sheets has a high preservation potential for biological material and chemical compounds that can be used to document the presence of active microbial metabolism at sub-zero temperatures. The concentration and isotopic composition of gases, in conjunction with other aqueous chemical species in debris-rich basal glacier ice from Taylor Glacier, Antarctica were used as direct evidence that cells entrained in the ice remain metabolically active at temperatures as low as -17°C, likely in thin films of liquid water along ice crystal and mineral grain boundaries. δ18O2 and δ13CO2 values measured in the ice are consistent with the hypothesis that abrupt changes measured in O2 and CO2 concentrations between debris-rich and debris-poor ice are due to in situ microbial mineralization of organic carbon. Low temperature culture-based experiments conducted using organisms isolated from the ice indicate the ability to respire organic carbon to CO2 under oxic conditions and under anoxic conditions couple carbon mineralization to dissimilatory iron reduction using Fe3+ as an electron acceptor. Microorganisms that are active in the debris-rich basal ice layers in terrestrial polar ice masses need to be adapted to surviving subzero temperatures and saline conditions on extended timescales. Thus these terrestrial glacial systems and the isotopic and geochemical biomarkers therein provide good analogues for guiding exploration and analysis of debris-rich ices in extraterrestrial settings, for example, on Mars.

  19. 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.

  20. Numerical simulation of separated flows in channels

    Science.gov (United States)

    Louda, Petr; Příhoda, Jaromír; Sváček, Petr; Kozel, Karel

    2012-04-01

    The work deals with numerical modelling of turbulent flows in channels with an expansion of the cross-section where flow separation and reattachment occur. The performance of several eddy viscosity models and an explicit algebraic Reynolds stress model (EARSM) is studied. The used test cases are flows in channels with various backward facing steps where the step is perpendicular or inclined and the top wall is parallel or deflected. Furthermore, a channel with the circular ramp is considered. The numerical solution is achieved by the finite volume method or by the finite element method. The results of both numerical approaches are compared.

  1. 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.

  2. 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...

  3. Canadian Activities in Space Debris Mitigation Technologies

    Science.gov (United States)

    Nikanpour, Darius; Jiang, Xin Xiang; Goroshin, Samuel; Haddad, Emile; Kruzelecky, Roman; Hoa, Suong; Merle, Philippe; Kleiman, Jacob; Gendron, Stephane; Higgins, Andrew; Jamroz, Wes

    The space environment, and in particular the Low Earth Orbit (LEO), is becoming increasingly populated with space debris which include fragments of dysfunctional spacecraft parts and materials traveling at speeds up to 15 km per second. These pose an escalating potential threat to LEO spacecraft, the international space station, and manned missions. This paper presents the Canadian activities to address the concerns over space debris in terms of debris mitigation measures and technologies; these include novel spacecraft demise technologies to safely decommission the spacecraft at the end of the mission, integrated self-healing material technologies for spacecraft structures to facilitate self-repair and help maintain the spacecraft structural and thermal performance, hypervelocity ground test capability to predict the impact of space debris on spacecraft performance, and ways of raising awareness within the space community through participation in targeted Science and Technology conferences and international forums.

  4. 33 CFR 151.3000 - Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and Reduction Act. 151.3000 Section 151.3000... Definition of Marine Debris for the Purposes of the Marine Debris Research, Prevention, and Reduction Act...

  5. Acquisition of TMI-2 core debris samples

    International Nuclear Information System (INIS)

    Owen, D.E.; Fee, D.S.; Bower, J.M.

    1983-01-01

    Recently the first samples of material were obtained from the damaged TMI-2 reactor core. This paper reviews the design and operation of the specialized equipment used to acquire these samples. In addition to two unique core debris rubble bed samplers, a 14-m-long sampler deployment boom, radiation shielding, and sample casks were designed and fabricated for the task. Analysis of the six TMI-2 core debris specimens obtained are presently underway at several laboratories, and the analysis plans are presented

  6. [Aortic debris in cerebrovascular ischemic disease].

    Science.gov (United States)

    Curatolo, L M; Melcón, C M; Lourido, M A; Torres-Lynch, M F; Parisi, V L; Fernández, G G; Rubachin, S; Hernández, G; Rotta-Escalante, R

    The aortic atherosclerotic debris is considered a high risk embolic source, being an independent predictor for cerebrovascular ischemia. The incidence is higher in the elderly and in patients with coronary artery disease. Transesophageal echocardiogram (TEE) is an important diagnostic tool that allows its detection. To describe characteristics of patients with ischemic stroke and echocardiographic diagnosis of aortic debris. We analyzed the group of patients with debris diagnosis in 209 TEE performed between 01/01/99 and 31/05/02, in 835 consecutive ischemic events. The information was collected from the Stroke Database of the Neurology Department of Policlinica Bancaria. TEE was accomplished in 25% of all assisted events. The mean age was 66.56 years (SD 11.22). In 30 studies (14%) aortic debris was detected. In this group of patients, 26 men and 4 women, was also found: plaques grade IV 60%, left atrial dilatation 40% and spontaneous echo contrast 20%. The most frequent risk factors were hypertension, dislipemia and smoking, with no significative difference compared to the group without debris. 40% had a prior cerebrovascular event. They presented with clinical subtype LACI 53%, PACI 27%, POCI 17%. 63% of patients had lacunar infarct (53% anterior and 10% posterior). The contribution of TTE for detection of embolic sources is relevant. A high percentage of the population with echocardiographic diagnosis of aortic debris, had a lacunar infarct, defined radiologically and by clinical features.

  7. Postdetonation nuclear debris for attribution.

    Science.gov (United States)

    Fahey, A J; Zeissler, C J; Newbury, D E; Davis, J; Lindstrom, R M

    2010-11-23

    On the morning of July 16, 1945, the first atomic bomb was exploded in New Mexico on the White Sands Proving Ground. The device was a plutonium implosion device similar to the device that destroyed Nagasaki, Japan, on August 9 of that same year. Recently, with the enactment of US public law 111-140, the "Nuclear Forensics and Attribution Act," scientists in the government and academia have been able, in earnest, to consider what type of forensic-style information may be obtained after a nuclear detonation. To conduct a robust attribution process for an exploded device placed by a nonstate actor, forensic analysis must yield information about not only the nuclear material in the device but about other materials that went into its construction. We have performed an investigation of glassed ground debris from the first nuclear test showing correlations among multiple analytical techniques. Surprisingly, there is strong evidence, obtainable only through microanalysis, that secondary materials used in the device can be identified and positively associated with the nuclear material.

  8. Plastic debris in Mediterranean seabirds.

    Science.gov (United States)

    Codina-García, Marina; Militão, Teresa; Moreno, Javier; González-Solís, Jacob

    2013-12-15

    Plastic debris is often ingested by marine predators and can cause health disorders and even death. We present the first assessment of plastic ingestion in Mediterranean seabirds. We quantified and measured plastics accumulated in the stomach of 171 birds from 9 species accidentally caught by longliners in the western Mediterranean from 2003 to 2010. Cory's shearwaters (Calonectris diomedea) showed the highest occurrence (94%) and large numbers of small plastic particles per affected bird (on average N = 15.3 ± 24.4 plastics and mass = 23.4 ± 49.6 mg), followed by Yelkouan shearwaters (Puffinus yelkouan, 70%, N = 7.0 ± 7.9, 42.1 ± 100.0 mg), Balearic shearwaters (Puffinus mauretanicus, 70%, N = 3.6 ± 2.9, 5.5 ± 9.7 mg) and the rest of species (below 33%, N = 2.7, 113.6 ± 128.4 mg). Plastic characteristics did not differ between sexes and were not related to the physical condition of the birds. Our results point out the three endemic and threatened shearwater species as being particularly exposed to plastic accumulation.

  9. 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.

  10. 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.

  11. Accumulation and fragmentation of plastic debris in global environments

    OpenAIRE

    Barnes, David K. A.; Galgani, Francois; Thompson, Richard C.; Barlaz, Morton

    2009-01-01

    One of the most ubiquitous and long-lasting recent changes to the surface of our planet is the accumulation and fragmentation of plastics. Within just a few decades since mass production of plastic products commenced in the 1950s, plastic debris has accumulated in terrestrial environments, in the open ocean, on shorelines of even the most remote islands and in the deep sea. Annual clean-up operations, costing millions of pounds sterling, are now organized in many countries and on every contin...

  12. Biodiversity: invasions by marine life on plastic debris.

    Science.gov (United States)

    Barnes, David K A

    2002-04-25

    Colonization by alien species poses one of the greatest threats to global biodiversity. Here I investigate the colonization by marine organisms of drift debris deposited on the shores of 30 remote islands from the Arctic to the Antarctic (across all oceans) and find that human litter more than doubles the rafting opportunities for biota, particularly at high latitudes. Although the poles may be protected from invasion by freezing sea surface temperatures, these may be under threat as the fastest-warming areas anywhere are at these latitudes.

  13. Debris filtering effectiveness and pressure drop tests of debris resistance-bottom end piece

    International Nuclear Information System (INIS)

    Chung, Moon Ki; Song, Chul Hwa; Chung, Heung June; Won, Soon Yeun; Cho, Young Ro; Kim, Bok Deuk

    1992-03-01

    In this final report, described are the test conditions and test procedures for the debris filtering effectiveness and pressure drop tests for developing the Debris Resistance-Bottom End Piece (DR-BEP). And the test results are tabulated for later evaluation. (Author)

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

    International Nuclear Information System (INIS)

    Garcia, E.C.; Porter, C.L.; Wallace, M.T.

    1993-01-01

    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

  15. 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. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Description and analysis of major debris flows occurred during 2008 in the Eastern Pyrenees

    Science.gov (United States)

    Chevalier, G.; Postilla, M.; Hürlimann, M.

    2009-04-01

    In the Eastern Pyrenees, debris flows are not as frequent as in other mountainous areas such as the Alps. Nevertheless, several important events have occurred in 2008 provoking damages to essential infrastructures and causing large economic loss. A rainstorm at the beginning of June 2008 generated various surficial slides and debris flows in the area of Berga, located in the Pre-Pyrenees. A major flow obstructed the tunnel entrance of a national road during several days. Another rainstorm on August 1 caused several debris flows and debris floods in the Southern sector of Andorra, situated in the Axial Pyrenees. The most important event occurred in the Riu Runer torrent and destroyed the main building at the Andorran border. Finally, a large debris flow was triggered by a thunderstorm on September 11 near Rialp, Axial Pyrenees. Some installations of Port-Ainé's ski-resort were damaged and its access road was destroyed at several points. Preliminary results of these three events are presented focussing on the initiation, flow behaviour and deposition processes. Moreover, the influence of human activity on the initiation was analysed. Field surveys and interpretation of aerial photographs are carried out in order to obtain geomorphologic information as well as data on the hydraulic characteristics. Additionally, rainfall as triggering is studied using records from nearby observation stations and data from weather radars. Finally, the dynamic behaviour is simulated at one site applying numerical modelling. Volume estimates of the two events occurred in the Axial Pyrenees range from 5000 up to 10000 m3. These are rather large magnitudes compared to historic debris flows in the same area. The initiation process of both events can be defined as in-channel formation. Field observations indicated important erosion rates of up to 10 m3/m characteristic of the high flow velocities estimated along the flow trajectory. In contrast, the Berga event was caused by a surficial

  17. 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.

  18. Cetaceans and Marine Debris: The Great Unknown

    Directory of Open Access Journals (Sweden)

    Mark Peter Simmonds

    2012-01-01

    Full Text Available Plastics and other marine debris have been found in the gastrointestinal tracts of cetaceans, including instances where large quantities of material have been found that are likely to cause impairment to digestive processes and other examples, where other morbidity and even death have resulted. In some instances, debris may have been ingested as a result of the stranding process and, in others, it may have been ingested when feeding. Those species that are suction or “ram” feeders may be most at risk. There is also evidence of entanglement of cetaceans in marine debris. However, it is usually difficult to distinguish entanglement in active fishing gear from that in lost or discarded gear. The overall significance of the threat from ingested plastics and other debris remains unclear for any population or species of cetaceans, although there are concerns for some taxa, including at the population level, and marine debris in the oceans continues to grow. Further research including the compilation of unpublished material and the investigation of important habitat areas is strongly recommended.

  19. ESA Technologies for Space Debris Remediation

    Science.gov (United States)

    Wormnes, K.; Le Letty, R.; Summerer, L.; Schonenborg, R.; Dubois-Matra, O.; Luraschi, E.; Cropp, A.; Krag, H.; Delaval, J.

    2013-08-01

    Space debris is an existing and growing problem for space operations. Studies show that for a continued use of LEO, 5 - 10 large and strategically chosen debris need to be removed every year. The European Space Agency (ESA) is actively pursuing technologies and systems for space debris removal under its Clean Space initiative. This overview paper describes the activities that are currently ongoing at ESA and that have already been completed. Additionally it outlines the plan for the near future. The technologies under study fall in two main categories corresponding to whether a pushing or a pulling manoeuvre is required for the de-orbitation. ESA is studying the option of using a tethered capture system for controlled de-orbitation through pulling where the capture is performed using throw-nets or alternatively a harpoon. The Agency is also studying rigid capture systems with a particular emphasis on tentacles (potentially combined with a robotic arm). Here the de-orbitation is achieved through a push-manoeuvre. Additionally, a number of activities will be discussed that are ongoing to develop supporting technologies for these scenarios, or to develop systems for de-orbiting debris that can be allowed to re-enter in an uncontrolled manner. The short term goal and main driver for the current technology developments is to achieve sufficient TRL on required technologies to support a potential de-orbitation mission to remove a large and strategically chosen piece of debris.

  20. Debris disc constraints on planetesimal formation

    Science.gov (United States)

    Krivov, Alexander V.; Ide, Aljoscha; Löhne, Torsten; Johansen, Anders; Blum, Jürgen

    2018-02-01

    Two basic routes for planetesimal formation have been proposed over the last decades. One is a classical `slow-growth' scenario. Another one is particle concentration models, in which small pebbles are concentrated locally and then collapse gravitationally to form planetesimals. Both types of models make certain predictions for the size spectrum and internal structure of newly born planetesimals. We use these predictions as input to simulate collisional evolution of debris discs left after the gas dispersal. The debris disc emission as a function of a system's age computed in these simulations is compared with several Spitzer and Herschel debris disc surveys around A-type stars. We confirm that the observed brightness evolution for the majority of discs can be reproduced by classical models. Further, we find that it is equally consistent with the size distribution of planetesimals predicted by particle concentration models - provided the objects are loosely bound `pebble piles' as these models also predict. Regardless of the assumed planetesimal formation mechanism, explaining the brightest debris discs in the samples uncovers a `disc mass problem'. To reproduce such discs by collisional simulations, a total mass of planetesimals of up to ˜1000 Earth masses is required, which exceeds the total mass of solids available in the protoplanetary progenitors of debris discs. This may indicate that stirring was delayed in some of the bright discs, that giant impacts occurred recently in some of them, that some systems may be younger than previously thought or that non-collisional processes contribute significantly to the dust production.

  1. Determining the Importance of Microbial Processes on Gas Composition in Debris-Rich Antarctic Basal Ice Using Isotope Geochemistry

    Science.gov (United States)

    Montross, S. N.; Skidmore, M. L.; Christner, B. C.; Doyle, S. M.; Tison, J.; Samyn, D.; Sowers, T. A.

    2010-12-01

    The volume and composition of air trapped in debris-rich basal ice results not only from initial entrainment processes, but also from processes that operate in the basal zone of polar glaciers and ice sheets following entrainment. Here we report on the concentration and isotopic composition of gases in debris-rich basal ice from Taylor Glacier, Antarctica and a biological role in both gas consumption and production. Microbial cell and total dissolved solute concentrations are highest in the debris-rich facies where CO2 concentrations are also significantly elevated over atmospheric concentrations. Thawed basal ice samples amended with 14C-acetate respired this substrate at low (2oC) incubation temperatures, and the maximum respiration rate was ~10-fold higher in samples with a debris content > ~ 1% wt/vol. δ18O2 and δ13CO2 values measured are consistent with the hypothesis that changes in gas chemistry observed in the debris-rich ice, i.e. a negative correlation between CO2 and O2 concentrations, are a result of microbial respiration in the ice. This mode of respiration utilizes O2(g) to oxidize organic carbon derived from entrained debris producing CO2(g) as a metabolic byproduct. This work utilizes an isotope mass balance model to provide the first comprehensive account of the physical, chemical, and biological sources of CO2 in debris-rich basal ice.

  2. Ingestion of marine plastic debris by green turtle(Chelonia mydas) in davao gulf, Mindanao, Philippines

    NARCIS (Netherlands)

    Abreo, Neil A.S.; Macusi, Edison D.; Blatchley, Darrell D.

    2016-01-01

    Marine plastic debris is a global problem that is threatening marine biodiversity. Different marine organisms have been exposed to the lethal and sub-lethal effects of this problem. Sub-lethal effects include reduced fitness due to reduced feeding, reduced reproductive output, limb amputation,

  3. Soil respiration and carbon responses to logging debris and competing vegetation

    Science.gov (United States)

    Robert A. Slesak; Stephen H. Schoenholtz; Timothy B. Harrington

    2010-01-01

    Management practices following forest harvesting that modify organic matter (OM) inputs and influence changes in the soil environment have the potential to alter soil C pools, but there is still much uncertainty regarding how these practices influence soil C flux. We examined the influence of varying amounts of logging-debris retention (0, 40, and 80% coverage) and...

  4. A regional reconstruction of debris-flow activity in the Northern Calcareous Alps, Austria

    Science.gov (United States)

    Procter, Emily; Bollschweiler, Michelle; Stoffel, Markus; Neumann, Mathias

    2011-09-01

    Dendrogeomorphic dating of historical debris-flow events is a highly valuable tool for improving historical records in the field of natural hazard management. Previous dendrogeomorphic investigations generally have focused on case studies of single torrents; however, regional investigations may offer a more accurate reconstruction of regional patterns of activity and therefore may have an advantage over individual cases. The aim of the study is to provide a regional reconstruction of debris-flow events for a site in the Northern Calcareous Alps of western Austria (Gamperdonatal, Vorarlberg) and to document spatial and temporal morphological changes in individual and neighboring torrents. Analysis of 442 trees (268 Pinus mugo ssp. uncinata, 164 Picea abies, and 10 Abies alba) allowed identification of 579 growth disturbances corresponding to 63 debris-flow events since A.D. 1839. The majority of growth disturbances were in the form of growth suppression or release (76%) owing to the nature of both the deposited material and the process characteristics. Regional patterns of event frequency indicated a paucity of activity in the early to mid-twentieth century and increased activity since A.D. 1948, whereby large events were followed by subsequent years of continued activity of smaller magnitude. Patterns of frequency could be attributed primarily to spatiotemporal changes in channel morphology, but may also be reflective of changes in transport conditions within the valley. This study provides the first regional investigation in the Austrian Alps and contributes to the documentation of tree responses to geomorphic disturbances in calcareous material.

  5. Space debris and related legal issues

    Science.gov (United States)

    Lafferranderie, G.

    2001-10-01

    "We are now witnessing an extraordinary event, the first of the 21st century, the MIR space station's plunge to Earth, producing of course impressive fireworks, but also a massive amount of debris." The first launchings created the first space debris. Space debris is the immediate, logical consequence of the exploration and use of outer space (around the Earth) involving manmade objects. This situation will persist, making launching, exploration and use increasingly difficult and risky - unless we turn to the type of rocket dreamt up by Hergé for Tintin's trips to the Moon. Worldwide concern has been expressed in particular in the Vienna Space Millennium Declaration adopted at the Unispace Conference in Vienna in July 1999, with the contributions of the Space Law Workshop organised by the International Institute of Space Law (session eight).

  6. Flow characteristics of counter-current flow in debris bed

    International Nuclear Information System (INIS)

    Abe, Yutaka; Adachi, Hiromichi

    2004-01-01

    In the course of a severe accident, a damaged core would form a debris bed consisting of once-molten and fragmented fuel elements. It is necessary to evaluate the dryout heat flux for the judgment of the coolability of the debris bed during the severe accident. The dryout phenomena in the debris bed is dominated by the counter-current flow limitation (CCFL) in the debris bed. In this study, air-water counter-current flow behavior in the debris bed is experimentally investigated with glass particles simulating the debris beds. In this experiment, falling water flow rate and axial pressure distributions were experimentally measured. As the results, it is clarified that falling water flow rate becomes larger with the debris bed height and the pressure gradient in the upper region of the debris bed is different from that in the lower region of the debris bed. These results indicate that the dominant region for CCFL in the debris bed is identified near the top of the debris bed. Analytical results with annular flow model indicates that interfacial shear stress in the upper region of the debris bed is larger than that in the lower region of the debris bed. (author)

  7. Plastic marine debris on the Portuguese coastline: a matter of size?

    Science.gov (United States)

    Martins, J; Sobral, P

    2011-12-01

    Plastic debris is a worldwide threat to marine environments and Portugal is not immune to it. Though never quantified, items of all sizes can be found in the Portuguese coastline; therefore the objective of this work is the identification of main size classes in stranded plastic debris. Beaches sediment was sampled and in the laboratory plastic items were sorted in 11 classes from 10mm, counted and weighted. Plastic size ranged from 50 μm to 20 cm and microplastics (plastic fits in the smaller size classes, due to expected high residence time in the sea enhancing degradation processes, which increase surface exposure and potentially persistent organic pollutants (POP) adsorption. These results point out the important contribution of microplastics to marine debris pollution, its risks, and the need to set a higher focus on this size class. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Apparatus for controlling molten core debris

    International Nuclear Information System (INIS)

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

    1972-01-01

    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

  9. Electrometallurgical treatment of TMI-2 fuel debris

    International Nuclear Information System (INIS)

    Karell, E.J.; Gourishankar, K.V.; Johnson, G.K.

    1997-01-01

    Argonne National Laboratory (ANL) has developed an electrometallurgical treatment process suitable for conditioning DOE oxide spent fuel for long-term storage or disposal. The process consists of an initial oxide reduction step that converts the actinide oxides to a metallic form, followed by an electrochemical separation of uranium from the other fuel constituents. The final product of the process is a uniform set of stable waste forms suitable for long-term storage or disposal. The suitability of the process for treating core debris from the Three Mile Island-2 (TMI-2) reactor is being evaluated. This paper reviews the results of preliminary experimental work performed using simulated TMI-2 fuel debris

  10. 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?

  11. Enabling Large-body Active Debris Removal, Phase II

    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...

  12. Enabling Large-body Active Debris Removal, Phase I

    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...

  13. Develop metrics of tire debris on Texas highways : technical report.

    Science.gov (United States)

    2017-05-01

    This research effort estimated the amount, characteristics, costs, and safety implications of tire debris on Texas highways. The metrics developed by this research are based on several sources of data, including a statewide survey of debris removal p...

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

    OpenAIRE

    Ryan, Peter G.; Moore, Charles J.; van Franeker, Jan A.; Moloney, Coleen 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 by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infreque...

  15. The Orbital Debris Problem and the Challenges for Environment Remediation

    Science.gov (United States)

    Liou, J.-C.

    2013-01-01

    Orbital debris scientists from major international space agencies, including JAXA and NASA, have worked together to predict the trend of the future environment. A summary presentation was given to the United Nations in February 2013. The orbital debris population in LEO will continue to increase. Catastrophic collisions will continue to occur every 5 to 9 years center dot To limit the growth of the future debris population and to better protect future spacecraft, active debris removal, should be considered.

  16. Orbiting Debris: a Space Environmental Problem. Background Paper

    Science.gov (United States)

    1990-01-01

    Artificial debris, deposited in a multitude of orbits about the Earth as the result of the exploration and use of the space environment, poses a growing hazard to future space operations. Unless nations sharply reduce the amount of orbital debris they produce, future space activites could suffer loss of capability, loss of income, and even loss of life as a result of collisions between spacecraft and debris. This background paper discusses the sources of debris and how they can be greatly reduced.

  17. 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

  18. Space Shuttle Systems Engineering Processes for Liftoff Debris Risk Mitigation

    Science.gov (United States)

    Mitchell, Michael; Riley, Christopher

    2011-01-01

    This slide presentation reviews the systems engineering process designed to reduce the risk from debris during Space Shuttle Launching. This process begins the day of launch from the tanking to the vehicle tower clearance. Other debris risks (i.e., Ascent, and micrometeoroid orbital debit) are mentioned) but are not the subject of this presentation. The Liftoff debris systems engineering process and an example of how it works are reviewed (i.e.,STS-119 revealed a bolt liberation trend on the Fixed Service Structure (FSS) 275 level elevator room). The process includes preparation of a Certification of Flight Readiness (CoFR) that includes (1) Lift-off debris from previous mission dispositioned, (2) Flight acceptance rationale has been provided for Lift-off debris sources/causes (3) Lift-off debris mission support documentation, processes and tools are in place for the up-coming mission. The process includes a liftoff debris data collection that occurs after each launch. This includes a post launch walkdown, that records each liftoff debris, and the entry of the debris into a database, it also includes a review of the imagery from the launch, and a review of the instrumentation data. There is also a review of the debris transport analysis process, that includes temporal and spatial framework and a computational fluid dynamics (CFD) analysis. which incorporates a debris transport analyses (DTA), debris materials and impact tests, and impact analyses.

  19. 1 Mapping Debris Flow Susceptibility using Analytical Network ...

    Indian Academy of Sciences (India)

    54

    Several methods are available for identifying and mapping landslide and debris flow. 1 susceptibility (Aleotti ... map susceptibility and assumes that the spatial distribution of landslides or debris. 10 flow is determined by a ..... The vulnerability of materials to mobilize into a debris flow is sensitive to the. 27 gradation of slope ...

  20. 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.

  1. 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

  2. Challenges in Modeling Debris-Flow Initiation during the Exceptional September 2013 Northern Colorado Front Range Rainstorm

    Science.gov (United States)

    Baum, R. L.; Coe, J. A.; Godt, J.; Kean, J. W.

    2014-12-01

    Heavy rainfall during 9 - 13 September 2013 induced about 1100 debris flows in the foothills and mountains of the northern Colorado Front Range. Eye-witness accounts and fire-department records put the times of greatest landslide activity during the times of heaviest rainfall on September 12 - 13. Antecedent soil moisture was relatively low, particularly at elevations below 2250 m where many of the debris flows occurred, based on 45 - 125 mm of summer precipitation and absence of rainfall for about 2 weeks before the storm. Mapping from post-event imagery and field observations indicated that most debris flows initiated as small, shallow landslides. These landslides typically formed in colluvium that consisted of angular clasts in a sandy or silty matrix, depending on the nature of the parent bedrock. Weathered bedrock was partially exposed in the basal surfaces of many of the shallow source areas at depths ranging from 0.2 to 5 m, and source areas commonly occupied less than 500 m2. Although 49% of the source areas occurred in swales and 3 % in channels, where convergent flow might have contributed to pore-pressure build up during the rainfall, 48% of the source areas occurred on open slopes. Upslope contributing areas of most landslides (58%) were small (physical-properties variability. The low-moisture initial conditions require consideration of unsaturated zone effects. Ongoing fieldwork and computational modeling are aimed at addressing these challenges related to initiation of the September 2013 debris flows.

  3. Space Surveillance, Asteroids and Comets, and Space Debris. Volume 3: Space Debris Summary Report

    National Research Council Canada - National Science Library

    Naka, R

    1997-01-01

    .... NASA personnel predicted in 1978 that collisional cascading would be an important source of new orbital debris, possibly before the year 2000, and, as a result, would make low Earth orbits at Space...

  4. Plastic Debris Is a Human Health Issue

    NARCIS (Netherlands)

    Vethaak, A.D.; Leslie, H.A.

    2016-01-01

    The global threat of highly persistent plastic waste accumulating and fragmenting in the world’s oceans, inland waters and terrestrial environments is becoming increasingly evident.1−3 Humans are being exposed to both plastic particles and chemical additives being released from the plastic debris of

  5. Estimating Solar Radiation Pressure for GEO Debris

    Science.gov (United States)

    Chao, Cia-Chun George; Campbell, Spencer

    2009-03-01

    Earlier investigations and surveys show that over 700 trackable debris objects are drifting or librating in the GEO (geosynchronous Earth orbit) ring. The close monitoring of the motion of these debris objects is becoming increasingly important due to the potential collision risks to operational GEO satellites. A critical element in improving the ephemeris prediction accuracy of these objects is the determination of solar radiation pressure effects on the orbit. A computational procedure employing specially designed PC programs was developed for estimating the solar radiation pressure effect on GEO debris. Results of three sample cases show significant accuracy improvement in long-term ephemeris prediction. The post-fit residuals (σr=3.0, σi = 10, σc = 1.0 km) are in good agreement with that processed by an independent tool (TRACE). The noise in the post-fit residuals is believed to be due to the position uncertainty in the two line elements (TLE) data. This efficient method, once implemented, has the potential of achieving real-time monitoring of the GEO debris objects with position accuracy considerably better than 10 km in-track, 3 km radial and 1 km cross-track.

  6. Evaluating intensity parameters for debris flow vulnerability

    Science.gov (United States)

    Keiler, Margreth

    2014-05-01

    In mountain regions natural hazard processes such as debris flows or hyper-concentrated flows repeatedly lead to high damages. After an event, detailed documentation of the meteorological, hydrological and geomorphological indicators are standardized, and additional data on debris covering run out areas, indicators for processes velocity and transported volumes are gathered. Information on deposition height of debris is an important parameter to estimate the intensity of the process impacting the buildings and infrastructure and hence to establish vulnerability curves. However, the deposition height of mobilized material in settlements and on infrastructure is mostly not directly evaluated because recovery work starts immediately or even during the event leading to a removal of accumulated material. Different approaches exist to reconstruct deposition heights after torrent events, such as mind mapping, comparison of LIDAR-based DEM before and after the event as well as the reconstruction by using photo documentation and the estimation of deposition heights according to standardised elements at buildings and infrastructure. In our study, these different approaches to estimate deposition height and the spatial distribution of the accumulated material are applied and compared against each other by using the case study of the debris flow event in Brienz (Switzerland) which occurred during the serve flood events of August 2005 in the Alps. Within the analysis, different factors including overall costs and time consumption (manpower, equipment), accuracy and preciseness are compared and evaluated to establish optimal maps of the extent and deposition depth after torrent events and to integrate this information in the vulnerability analysis.

  7. 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...

  8. Cross-stratified Wood: Enigmatic Woody Debris Deposits in Warm-Polar Fluvial Sediments (Pliocene Beaufort Formation, Nunavut)

    Science.gov (United States)

    Davies, N. S.; Gosse, J. C.; Rybczynski, N.

    2012-04-01

    Woody debris has been an important sediment component and a significant geomorphic agent in pristine fluvial systems since the Devonian. In recent years a large volume of research has focussed on various aspects of the importance of woody debris within the fluvial realm; from the evolutionary significance of fossil wood accumulations in the rock record to studies of the biogeomorphological and ecological importance of woody debris in modern rivers. In this presentation we describe cross-stratified woody debris deposits comprising organic detritus from a boreal-type treeline forest that included species of pine, birch, poplar, alder, spruce, eastern cedar, and larch, in both shrub and tree form. The cross-stratified wood is an enigmatic subset of fine woody debris which, to our knowledge, has never before been described from either the global stratigraphic record or modern fluvial environments. The deposits we describe are located within the Pliocene Beaufort Formation on Meighen Island, Nunavut, Canada, at a latitude of 80°N, and are compared with other cross-stratified woody debris deposits that have been noted elsewhere in the Pliocene of the Canadian Arctic. We make the robust observation that these deposits appear to be geographically and stratigraphically restricted to polar latitudes from a period of warm climatic conditions during the Pliocene (15-20 °C warmer mean annual temperature than the present day). In this regard it is possible to speculate that the transport of large amounts of woody debris as bedload is potentially a unique feature of forested high latitude rivers. Such bedload deposition requires a large amount of woody debris with a greater density than the fluid transporting it. The softwood composition of the debris suggests that this was most likely attained by saturation and subsequent entrainment of extensive accumulations of deadwood, promoted by unusually high rates of tree mortality and low rates of bacterial decomposition arising from

  9. 15 CFR 909.1 - Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and...

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Definition of marine debris for the purposes of the Marine Debris Research, Prevention, and Reduction Act. 909.1 Section 909.1 Commerce and... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE GENERAL REGULATIONS MARINE DEBRIS § 909.1 Definition of...

  10. 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.

  11. Anthropogenic Debris Ingestion by Avifauna in Eastern Australia.

    Directory of Open Access Journals (Sweden)

    Lauren Roman

    Full Text Available 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.

  12. 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.

  13. Organics.

    Science.gov (United States)

    Chian, Edward S. K.; DeWalle, Foppe B.

    1978-01-01

    Presents water analysis literature for 1978. This review is concerned with organics, and it covers: (1) detergents and surfactants; (2) aliphatic and aromatic hydrocarbons; (3) pesticides and chlorinated hydrocarbons; and (4) naturally occurring organics. A list of 208 references is also presented. (HM)

  14. Organizers.

    Science.gov (United States)

    Callison, Daniel

    2000-01-01

    Focuses on "organizers," tools or techniques that provide identification and classification along with possible relationships or connections among ideas, concepts, and issues. Discusses David Ausubel's research and ideas concerning advance organizers; the implications of Ausubel's theory to curriculum and teaching; "webbing," a…

  15. Marine Debris Composition on Remote Alaskan National Park Shores

    Science.gov (United States)

    Pister, B.; Kunisch, E.; Polasek, L.; Bering, J.; Kim, S.; Neitlich, P.; Nicolato, K.

    2016-02-01

    Marine debris is a pervasive problem along coastlines around the world. The National Park Service manages approximately 3500 miles of shoreline in Alaska's national park units combined. Most of these shores are remote, difficult and expensive to access. In 2011 the Tohoku earthquake hit Japan and generated a devastating tsunami that washed an estimated 150 million tons of debris out to sea. Much of the debris washed ashore in Alaska. The tsunami brought new attention to the long standing problem of marine debris. In 2015 the National Park Service mounted a two pronged effort to remove as much debris as possible from the shores of five park units in Alaska, and initiate education programs about the issue. Almost 11,000 kg of debris were removed from the shores of: Wrangell-St. Elias National Park, Kenai Fjords National Park, Katmai National Park, Bering Land Bridge National Preserve and Cape Krusenstern National Monument. Approximately 58% of the debris was plastic. Although much of the debris resembled items expected as a result of the tsunami, a great percentage of the debris was clearly from other sources, such as fishing and shipping. Preliminary analysis suggests that debris composition varied significantly between parks, possibly from locally-derived sources. This can influence how the National Park Service creates educational outreach programs that focus on marine debris prevention exercises.

  16. 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.

  17. Protecting AREVA ATRIUM™ BWR fuel from debris fretting failure

    International Nuclear Information System (INIS)

    Cole, Steven E.; Garner, Norman L.; Lippert, Hans-Joachim; Graebert, Rüdiger; Mollard, Pierre; Hahn, Gregory C.

    2014-01-01

    Historically, debris fretting has been the leading cause of fuel rod failure in BWR fuel assemblies, costing the industry millions of dollars in lost generation and negatively impacting the working area of plant site personnel. In this paper the focus will be on recent BWR fuel product innovation designed to eliminate debris related failures. Experience feedback from more than three decades of operation history with non-line-of-sight FUELGUARD™ lower tie plate debris filters will be presented. The development and relative effectiveness of successive generations of filtration technology will be discussed. It will be shown that modern, state of the art debris filters are an effective defense against debris fretting failure. Protective measures extend beyond inlet nozzle debris filters. The comprehensive debris resistance features built into AREVA’s newest fuel design, the ATRIUM™ 11, reduce the overall risk of debris entrapment as well as providing a degree of protection from debris that may fall down on the fuel assembly from above, e.g., during refueling operations. The positive recent experience in a debris sensitive plant will be discussed showing that the combination of advanced fuel technology and a robust foreign material exclusion program at the reactor site can eliminate the debris fretting failure mechanism. (author)

  18. Evaluating the impacts of marine debris on cetaceans.

    Science.gov (United States)

    Baulch, Sarah; Perry, Clare

    2014-03-15

    Global in its distribution and pervading all levels of the water column, marine debris poses a serious threat to marine habitats and wildlife. For cetaceans, ingestion or entanglement in debris can cause chronic and acute injuries and increase pollutant loads, resulting in morbidity and mortality. However, knowledge of the severity of effects lags behind that for other species groups. This literature review examines the impacts of marine debris on cetaceans reported to date. It finds that ingestion of debris has been documented in 48 (56% of) cetacean species, with rates of ingestion as high as 31% in some populations. Debris-induced mortality rates of 0-22% of stranded animals were documented, suggesting that debris could be a significant conservation threat to some populations. We identify key data that need to be collected and published to improve understanding of the threat that marine debris poses to cetaceans. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. 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.

  20. 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.

  1. Organizations

    DEFF Research Database (Denmark)

    Hatch, Mary Jo

    Most of us recognize that organizations are everywhere. You meet them on every street corner in the form of families and shops, study in them, work for them, buy from them, pay taxes to them. But have you given much thought to where they came from, what they are today, and what they might become...... and considers many more. Mary Jo Hatch introduces the concept of organizations by presenting definitions and ideas drawn from the a variety of subject areas including the physical sciences, economics, sociology, psychology, anthropology, literature, and the visual and performing arts. Drawing on examples from...... prehistory and everyday life, from the animal kingdom as well as from business, government, and other formal organizations, Hatch provides a lively and thought provoking introduction to the process of organization....

  2. Organizations

    DEFF Research Database (Denmark)

    Hatch, Mary Jo

    and considers many more. Mary Jo Hatch introduces the concept of organizations by presenting definitions and ideas drawn from the a variety of subject areas including the physical sciences, economics, sociology, psychology, anthropology, literature, and the visual and performing arts. Drawing on examples from......Most of us recognize that organizations are everywhere. You meet them on every street corner in the form of families and shops, study in them, work for them, buy from them, pay taxes to them. But have you given much thought to where they came from, what they are today, and what they might become...... prehistory and everyday life, from the animal kingdom as well as from business, government, and other formal organizations, Hatch provides a lively and thought provoking introduction to the process of organization....

  3. 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.

  4. GENERALIZED VISCOPLASTIC MODELING OF DEBRIS FLOW.

    Science.gov (United States)

    Chen, Cheng-lung

    1988-01-01

    The earliest model developed by R. A. Bagnold was based on the concept of the 'dispersive' pressure generated by grain collisions. Some efforts have recently been made by theoreticians in non-Newtonian fluid mechanics to modify or improve Bagnold's concept or model. A viable rheological model should consist both of a rate-independent part and a rate-dependent part. A generalized viscoplastic fluid (GVF) model that has both parts as well as two major rheological properties (i. e. , the normal stress effect and soil yield criterion) is shown to be sufficiently accurate, yet practical for general use in debris-flow modeling. In fact, Bagnold's model is found to be only a particular case of the GVF model. analytical solutions for (steady) uniform debris flows in wide channels are obtained from the GVF model based on Bagnold's simplified assumption of constant grain concentration.

  5. 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.

  6. GENERAL SOLUTIONS FOR VISCOPLASTIC DEBRIS FLOW.

    Science.gov (United States)

    Chen, Cheng-lung

    1988-01-01

    Theoretical velocity profile and theoretical pressure and concentration distributions for (steady) uniform debris flow in wide channels are derived from a generalized viscoplastic fluid (GVF) model without imposing R. A. Bagnold's assumption of constant grain concentration. Good agreement between the theoretical velocity profile and the experimental data of Japanese scientists strongly supports the validity of both the GVF model and the proposed method of solution from the model. It is shown that both E. C. Bingham and Bagnold versions (or submodels) of the GVF model can be used to simulate debris flow at the dynamic state. Although Bagnold's dilatant submodel appears to fit the Japanese data better than the Bingham submodel for flow of noncohesive grains, the choice between them is by no means clear-cut.

  7. Plastic debris in the open ocean

    OpenAIRE

    Cózar, A. (Andrés); Echevarria, F. (Fidel); González-Gordillo, J.I. (Juan Ignacio); Irigoien, X. (Xabier); Úbeda, B. (Bárbara); Hernández-León, S. (Santiago); Palma, A.T. (Álvaro T.); Navarro, S. (Sandra); García-de-Lomas, J. (Juan); Ruiz, A. (Andrea); Fernández-de-Puelles, M.L. (María Luz); Duarte, C.M. (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. Howeve...

  8. 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.

  9. 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....

  10. Forewarning of Debris flows using Intelligent Geophones

    Science.gov (United States)

    PK, I.; Ramesh, M. V.

    2017-12-01

    Landslides are one of the major catastrophic disasters that cause significant damage to human life and civil structures. Heavy rainfall on landslide prone areas can lead to most dangerous debris flow, where the materials such as mud, sand, soil, rock, water and air will move with greater velocity down the mountain. This sudden slope instability can lead to loss of human life and infrastructure. According to our knowledge, till now no one could identify the minutest factors that lead to initiation of the landslide. In this work, we aim to study the landslide phenomena deeply, using the landslide laboratory set up in our university. This unique mechanical simulator for landslide initiation is equipped with the capability to generate rainfall, seepage, etc., in the laboratory setup. Using this setup, we aim to study several landslide initiation scenarios generated by varying different parameters. The complete setup will be equipped with heterogeneous sensors such as rain gauge, moisture sensor, pore pressure sensor, strain gauges, tiltmeter, inclinometer, extensometer, and geophones. Our work will focus on the signals received from the intelligent geophone system for identifying the underground vibrations during a debris flow. Using the large amount of signals derived from the laboratory set up, we have performed detailed signal processing and data analysis to determine the fore warning signals captured by these heterogeneous sensors. Detailed study of these heterogeneous signals has provided the insights to forewarning the community based on the signals generated during the laboratory tests. In this work we will describe the details of the design, development, methodology, results, inferences and the suggestion for the next step to detect and forewarn the students. The response of intelligent geophone sensors at the time of failure, failure style and subsequent debris flow for heterogeneous soil layers were studied, thus helping in the development of fore warning

  11. 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.

  12. Interactions of microplastic debris throughout the marine ecosystem.

    Science.gov (United States)

    Galloway, Tamara S; Cole, Matthew; Lewis, Ceri

    2017-04-20

    Marine microscopic plastic (microplastic) debris is a modern societal issue, illustrating the challenge of balancing the convenience of plastic in daily life with the prospect of causing ecological harm by careless disposal. Here we develop the concept of microplastic as a complex, dynamic mixture of polymers and additives, to which organic material and contaminants can successively bind to form an 'ecocorona', increasing the density and surface charge of particles and changing their bioavailability and toxicity. Chronic exposure to microplastic is rarely lethal, but can adversely affect individual animals, reducing feeding and depleting energy stores, with knock-on effects for fecundity and growth. We explore the extent to which ecological processes could be impacted, including altered behaviours, bioturbation and impacts on carbon flux to the deep ocean. We discuss how microplastic compares with other anthropogenic pollutants in terms of ecological risk, and consider the role of science and society in tackling this global issue in the future.

  13. Debris flow-induced topographic changes: effects of recurrent debris flow initiation.

    Science.gov (United States)

    Chen, Chien-Yuan; Wang, Qun

    2017-08-12

    Chushui Creek in Shengmu Village, Nantou County, Taiwan, was analyzed for recurrent debris flow using numerical modeling and geographic information system (GIS) spatial analysis. The two-dimensional water flood and mudflow simulation program FLO-2D were used to simulate debris flow induced by rainfall during typhoon Herb in 1996 and Mindulle in 2004. Changes in topographic characteristics after the debris flows were simulated for the initiation of hydrological characteristics, magnitude, and affected area. Changes in topographic characteristics included those in elevation, slope, aspect, stream power index (SPI), topographic wetness index (TWI), and hypsometric curve integral (HI), all of which were analyzed using GIS spatial analysis. The results show that the SPI and peak discharge in the basin increased after a recurrence of debris flow. The TWI was higher in 2003 than in 2004 and indicated higher potential of landslide initiation when the slope of the basin was steeper. The HI revealed that the basin was in its mature stage and was shifting toward the old stage. Numerical simulation demonstrated that the parameters' mean depth, maximum depth, affected area, mean flow rate, maximum flow rate, and peak flow discharge were increased after recurrent debris flow, and peak discharge occurred quickly.

  14. 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.

  15. 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

  16. 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.

  17. Treatment technology analysis for mixed waste containers and debris

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Brown, C.H.; Langton, C.A.; Askew, N.M.; Kan, T.; Schwinkendorf, W.E.

    1994-03-01

    A team was assembled to develop technology needs and strategies for treatment of mixed waste debris and empty containers in the Department of Energy (DOE) complex, and to determine the advantages and disadvantages of applying the Debris and Empty Container Rules to these wastes. These rules issued by the Environmental Protection Agency (EPA) apply only to the hazardous component of mixed debris. Hazardous debris that is subjected to regulations under the Atomic Energy Act because of its radioactivity (i.e., mixed debris) is also subject to the debris treatment standards. The issue of treating debris per the Resource Conservation and Recovery Act (RCRA) at the same time or in conjunction with decontamination of the radioactive contamination was also addressed. Resolution of this issue requires policy development by DOE Headquarters of de minimis concentrations for radioactivity and release of material to Subtitle D landfills or into the commercial sector. The task team recommends that, since alternate treatment technologies (for the hazardous component) are Best Demonstrated Available Technology (BDAT): (1) funding should focus on demonstration, testing, and evaluation of BDAT on mixed debris, (2) funding should also consider verification of alternative treatments for the decontamination of radioactive debris, and (3) DOE should establish criteria for the recycle/reuse or disposal of treated and decontaminated mixed debris as municipal waste

  18. Treatment technology analysis for mixed waste containers and debris

    Energy Technology Data Exchange (ETDEWEB)

    Gehrke, R.J. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Brown, C.H. [Oak Ridge National Lab., TN (United States); Langton, C.A.; Askew, N.M. [Savannah River Lab., Aiken, SC (United States); Kan, T. [Lawrence Livermore National Lab., CA (United States); Schwinkendorf, W.E. [BDM Federal, Inc., Albuquerque, NM (United States)

    1994-03-01

    A team was assembled to develop technology needs and strategies for treatment of mixed waste debris and empty containers in the Department of Energy (DOE) complex, and to determine the advantages and disadvantages of applying the Debris and Empty Container Rules to these wastes. These rules issued by the Environmental Protection Agency (EPA) apply only to the hazardous component of mixed debris. Hazardous debris that is subjected to regulations under the Atomic Energy Act because of its radioactivity (i.e., mixed debris) is also subject to the debris treatment standards. The issue of treating debris per the Resource Conservation and Recovery Act (RCRA) at the same time or in conjunction with decontamination of the radioactive contamination was also addressed. Resolution of this issue requires policy development by DOE Headquarters of de minimis concentrations for radioactivity and release of material to Subtitle D landfills or into the commercial sector. The task team recommends that, since alternate treatment technologies (for the hazardous component) are Best Demonstrated Available Technology (BDAT): (1) funding should focus on demonstration, testing, and evaluation of BDAT on mixed debris, (2) funding should also consider verification of alternative treatments for the decontamination of radioactive debris, and (3) DOE should establish criteria for the recycle/reuse or disposal of treated and decontaminated mixed debris as municipal waste.

  19. Woody debris along an upland chronosequence in boreal Manitoba and its impact on long-term carbon storage

    Science.gov (United States)

    Manies, K.L.; Harden, J.W.; Bond-Lamberty, B. P.; O'Neill, K. P.

    2005-01-01

    This study investigated the role of fire-killed woody debris as a source of soil carbon in black spruce (Picea mariana (Mill.) BSP) stands in Manitoba, Canada. We measured the amount of standing dead and downed woody debris along an upland chronosequence, including wood partially and completely covered by moss growth. Such woody debris is rarely included in measurement protocols and composed up to 26% of the total amount of woody debris in older stands, suggesting that it is important to measure all types of woody debris in ecosystems where burial by organic matter is possible. Based on these data and existing net primary production (NPP) values, we used a mass-balance model to assess the potential impact of fire-killed wood on long-term carbon storage at this site. The amount of carbon stored in deeper soil organic layers, which persists over millennia, was used to represent this long-term carbon. We estimate that between 10% and 60% of the deep-soil carbon is derived from wood biomass. Sensitivity analyses suggest that this estimate is most affected by the fire return interval, decay rate of wood, amount of NPP, and decay rate of the char (postfire) carbon pool. Landscape variations in these terms could account for large differences in deep-soil carbon. The model was less sensitive to fire consumption rates and to rates at which standing dead becomes woody debris. All model runs, however, suggest that woody debris plays an important role in long-term carbon storage for this area. ?? 2005 NRC Canada.

  20. 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

  1. 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

  2. Mapping marine debris across coastal communities in Belize: developing a baseline for understanding the distribution of litter on beaches using geographic information systems.

    Science.gov (United States)

    Bennett-Martin, Paulita; Visaggi, Christy C; Hawthorne, Timothy L

    2015-10-01

    Monitoring of marine debris (also known as marine litter) is an essential step in the process to eradicate ecological dangers in marine ecosystems caused by humans. This study examines marine debris in the Caribbean country of Belize using geographic information systems (GIS) to develop (1) a detailed data library for use on handheld Global Positioning System (GPS) units and tablets with mobile mapping applications for deployment in the field and (2) a freely available, online mapping portal to share data with Belizeans to encourage future citizen science efforts. Four diverse communities were targeted ranging from larger more populated towns, to smaller villages across central and southern Belize: San Pedro, Caye Caulker, Punta Gorda, and Monkey River. Fieldwork was conducted over 1 month, during which data points were collected in 50-m surveys followed by debris cleanup and removal. Features in our database included material, quantity, item, brand, and condition. Over 6000 pieces of debris were recorded in GIS for further analysis, and 299 gal of debris were removed from the shores of Belize. The most abundant form of debris observed was plastic (commonly bottles) across all locations; plastic comprised 77.6 % of all debris items observed. Through GIS, a detailed snapshot understanding of debris patterns across multiple settings in Belize was documented. Ongoing collaborations with local organizations in Belize have demonstrated significant interest and utility for such GIS approaches in analyzing and managing marine debris. The data, methodology, visual representations, and online mapping platform resulting from this research are a first step in directly supporting local Belizean community advocacy and policy, while contributing to larger institutional strategies for addressing marine debris issues in the Caribbean.

  3. The amount and accumulation rate of plastic debris on marshes and beaches on the Georgia coast.

    Science.gov (United States)

    Lee, Richard F; Sanders, Dorothea P

    2015-02-15

    The amount and accumulation rate of plastic debris at 20 sites along the Georgia coast were prepared using data reported by a number of volunteer organizations. The amount of plastic debris at highly visited barrier island beaches and estuarine marshes ranged from 300 to >1000 kg. Relatively large amount of plastics (180-500 kg) were found on less visited barrier island beaches, i.e. Blackbeard, Ossabaw and Cumberland Islands. A follow up monthly or quarterly collection study was carried out on two of the sites, a barrier beach and estuarine marsh, to determine accumulation rate in 8000 m(2) areas. Accumulation rates ranged from 0.18 to 1.28 kg/30 days-8000 m(2) on the barrier island beach and from 0.6 to 1.61 kg/30 days-8000 m(2) at the estuarine marsh site. The major type of plastics, e.g. bottles, food wrappers, plastic fragments, was highly variable at different seasons and sites. The authors recommend consideration of a standardization in reporting plastic debris, with respect to quantitation of debris and sample area. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. 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

  5. Rainfalls inducing debris avalanches-debris flows in the pyroclastic deposits of Campania, southern Italy

    Science.gov (United States)

    Fiorillo, F.; Giulivo, I.; Guadagno, F.; Revellino, P.

    2003-04-01

    In May 1998, following an intense rainstorm, the Sarno-Quindici area was involved in flows which struck the downslope towns, causing a high number of casualties and the destruction of several houses and infrastructures. In December 1999, about one year later, prolonged rainfalls triggered similar landslides in the Valle Caudina area, causing deaths and serious damages in the town of Cervinara. These events are the most recent ones of those that have effected areas around the Campania Plain, where pyroclastic covers mantle the calcareous ridges. This setting can be considered as an “unicum” characterised by alloctonous superficial soil formations not genetically connected to the bedrock. The consequence of the successive volcanic eruptions is the formation of a multi-layered pyroclastic cover, where layers and soil horizons have different geotechnical and hydrogeological properties. This setting is fundamental to the development of landslide phenomena, as it controls the mechanical and hydrological behaviour of the slope. Generally, the instabilities initiate as a small debris slide which develop into large, shallow debris avalanches and debris flows involving the pyroclastic horizons and the colluvial soils on steep and vegetated slopes, often at the heads of gullies. During motion, the landslide materials, also due to the acquired height velocity, erode vegetation and soil from the slope, so that the moving volume tends to increase. Then at the bases of the slope, phenomena evolve in hyperconcentrated steamflow due to dilution by incorporating water. The analysis carried out on main historical storms of Campania area (Sarno-Quindici and Sorrentina Peninsula) shows that debris phenomena occurred mainly in the wet season, after high-value of the rainfall pre-storms. Due to high quality recording of December 1999 storm, which induced many debris flows in Cervinara area, a detailed hydrological-statistical analysis has been carried out. This storm occurred after

  6. 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......: hillslope debris flow): a very rapid to extremely rapid non-channelised downslope movement of remoulded colluvium and eventually fragmented rock, initiated as a debris slide in colluvial soil (type 1) or from rock fall (type 2). Áar-skriðulop (English translation: channelised debris flow): a very rapid...... to extremely rapid channelised downslope movement of remoulded colluvium and/or talus/fluvial material and eventually fragmented rock, initiated as a debris slide in colluvial soil (type 1), from rock fall (type 2) or from mobilisation of talus/fluvial material (type 3). The scheme, which is compatible...

  7. 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.

  8. Protecting Spacecraft Fragments from Exposure to Small Debris

    OpenAIRE

    V. V. Zelentsov

    2015-01-01

    Since the launch of the first artificial Earth satellite a large amount of space debris has been accumulated in near-earth space. This debris comprises the exhausted spacecrafts, final stages of rocket-carriers and boosters, technological space junk, consisting of the structure elements, which are separated when deploying the solar arrays, antennas etc., as well as when undocking a booster and a spacecraft. All the debris is divided into observable one of over 100 mm in size and unobservable ...

  9. Anthropogenic effect on avalanche and debris flow activity

    OpenAIRE

    S. A. Sokratov; Yu. G. Seliverstov; A. L. Shnyparkov; K. P. Koltermann

    2013-01-01

    The paper presents examples of the change in snow avalanches and debris flows activity due to the anthropogenic pressure on vegetation and relief. The changes in dynamical characteristics of selected snow avalanches and debris flows due to the anthropogenic activity are quantified. The conclusion is made that the anthropogenic effects on the snow avalanches and debris flows activity are more pronounced than the possible effects of the climate change. The necessity is expressed on the unavoida...

  10. Modeling the fate and transport of plastic debris in freshwaters

    OpenAIRE

    Kooi, Merel; Besseling, Ellen; Kroeze, Carolien; Wenzel, van, Annemarie P.; Koelmans, Albert A.

    2018-01-01

    Contamination with plastic debris has been recognized as one of today’s major environmental quality problems. Because most of the sources are land based, concerns are increasingly focused on the freshwater and terrestrial environment. Fate and transport models for plastic debris can complement information from measurements and will play an important role in the prospective risk assessment of plastic debris. We review the present knowledge with respect to fate and transport modeling of plastic...

  11. An Optical Navigation System for Capturing Space Debris

    Science.gov (United States)

    2016-03-30

    d. Simple light weight robot arm for debris capture e. Debris removal by electro-dynamic tether package included in thebottom of the simple robot ...Capturing of Target by Robot Arm Deployment of Electro-Dynamic- Tether 7 th Asia-Pacific International Symposium on Aerospace Technology, 25 – 27...measures. A micro robotic satellite with a simple robot arm for active space debris removal has been studied. Capture is an indispensable task for the

  12. Mercury-Contaminated Hydraulic Mining Debris in San Francisco Bay

    Directory of Open Access Journals (Sweden)

    Robin M Bouse

    2010-05-01

    Full Text Available The hydraulic gold-mining process used during the California Gold Rush and in many developing countries today contributes enormous amounts of sediment to rivers and streams. Commonly, accompanying this sediment are contaminants such as elemental mercury and cyanide used in the gold extraction process. We show that some of the mercury-contaminated sediment created by hydraulic gold mining in the Sierra Nevada, between 1852 and 1884, ended up over 250 kilometers (km away in San Francisco Bay; an example of the far-reaching extent of contamination from such activities. A combination of radionuclide dating, bathymetric reconstruction, and geochemical tracers were used to distinguish the hydraulic mining sediment from sediment deposited in the bay before hydraulic mining started (pre-Gold Rush sediment and sediment deposited after hydraulic mining stopped (modern sediment. Three San Francisco Bay cores were studied as well as source material from the abandoned hydraulic gold mines and river sediment between the mines and bay. Isotopic and geochemical compositions of the core sediments show a geochemical shift in sediment deposited during the time of hydraulic mining. The geochemical shift is characterized by a decrease in εNd, total organic carbon (TOC, Sr and Ca concentrations, Ca/Sr, and Ni/Zr; and, an increase in 87Sr/86Sr, Al/Ca, Hg concentrations, and quartz/plagioclase. This shift is in the direction of the geochemical signature of sediments from rivers and gold mines in hydraulic mining areas. Mixing calculations using Nd isotopes and concentrations estimate that the hydraulic mining debris comprises up to 56% of the sediment in core sediments deposited during the time of hydraulic mining. The surface sediment of cores taken in 1990 were found to contain up to 43% hydraulic mining debris, reflecting a continuing remobilization and redistribution of the debris within the bay and transport from the watershed. Mercury concentrations in pre

  13. Cleaning space debris with a space-based laser system

    OpenAIRE

    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 concen...

  14. Cleaning space debris with a space-based laser system

    Directory of Open Access Journals (Sweden)

    Shen Shuangyan

    2014-08-01

    Full Text Available 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.

  15. Marine debris removal: one year of effort by the Georgia Sea Turtle-Center-Marine Debris Initiative.

    Science.gov (United States)

    Martin, Jeannie Miller

    2013-09-15

    Once in the marine environment, debris poses a significant threat to marine life that can be prevented through the help of citizen science. Marine debris is any manufactured item that enters the ocean regardless of source, commonly plastics, metal, wood, glass, foam, cloth, or rubber. Citizen science is an effective way to engage volunteers in conservation initiatives and provide education and skill development. The Georgia Sea Turtle Center Marine Debris Initiative (GSTC-MDI) is a grant funded program developed to engage citizens in the removal of marine debris from the beaches of Jekyll Island, GA, USA and the surrounding areas. During the first year of effort, more than 200 volunteers donated over 460 h of service to the removal of marine debris. Of the debris removed, approximately 89% were plastics, with a significant portion being cigarette materials. Given the successful first year, the GSTC-MDI was funded again for a second year. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. 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.

  17. Circumstellar Gas in Young Planetary Debris Disks

    Science.gov (United States)

    Roberge, A.

    Circumstellar (CS) disks orbiting young stars fall into two categories: primordial disks, composed of unprocessed interstellar dust and gas, and debris disks, produced by the destruction of solid planetary bodies. In the first class, the most abundant gas is H_2; in the second, it appears that the H_2 gas has disappeared, possibly through incorporation into gas giant planets. The lifetime of H_2 gas in a CS disk is therefore of great importance, as it dictates the timescale for the formation of giant planets. FUSE observations of H_2 in CS disk systems have shown that FUV absorption spectroscopy may sensitively probe for small amounts of gas along the line of sight to the star. Most importantly, the FUSE non-detection of H_2 gas in the Beta Pictoris disk suggests that the primordial gas lifetime is less than about 12 Myr, and that gas giant planets must form very quickly. However, this suggestion is based on one system, and needs to be tested in additional systems with a range of ages, especially since there are indications that age is not the only factor in the evolution of a CS disk. We propose for FUSE observations of 3 additional debris disk systems, Fomalhaut, HD3003, and HD2884. Fomalhaut is an intermediate age debris disk, one of the Fabulous Four CS disks first discovered in 1984. The other two disks are younger, with ages similar to that of Beta Pic. All three stars are brighter in the FUV than Beta Pic, permitting us to sensitively probe for traces of H_2 gas. We will also measure the amount of secondary atomic gas produced from planetary bodies in these disks, in an effort to understand the entire evolution of CS gas in young planetary systems.

  18. Anthropogenic debris in seafood: Plastic debris and fibers from textiles in fish and bivalves sold for human consumption

    OpenAIRE

    Rochman, CM; Tahir, A; Williams, SL; Baxa, DV; Lam, R; Miller, JT; Teh, FC; Werorilangi, S; Teh, SJ

    2015-01-01

    UNHAS and UCD Research Collaboration The ubiquity of anthropogenic debris in hundreds of species of wildlife and the toxicity of chemicals associated with it has begun to raise concerns regarding the presence of anthropogenic debris in seafood. We assessed the presence of anthropogenic debris in fishes and shellfish on sale for human consumption. We sampled from markets in Makassar, Indonesia, and from California, USA. All fish and shellfish were identified to species where possible. Anthr...

  19. 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.

  20. Modelling untrackable orbital debris associated with a tracked space debris cloud.

    Science.gov (United States)

    Culp, R. D.; Madler, R. A.

    A computer model, including both the trackable and untrackable size regimes, has been developed to simulate several types of satellite fragmentations. These particle swarms are then propagated using a perturbation model to predict the collision hazard associated with the entire swarm. The results of this study will aid in estimating the long term hazard posed by debris particles to operating satellites and space operations.

  1. 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.

  2. Data Acquisition, Management, and Analysis in Support of the Audiology and Hearing Conservation and the Orbital Debris Program Office

    Science.gov (United States)

    Dicken, Todd

    2012-01-01

    My internship at Johnson Space Center, Houston TX comprised of working simultaneously in the Space Life Science Directorate (Clinical Services Branch, SD3) in Audiology and Hearing Conservation and in the Astromaterials Research and Exploration Sciences Directorate in the Orbital Debris Program Office (KX). The purpose of the project done to support the Audiology and Hearing Conservation Clinic (AuHCon) is to organize and analyze auditory test data that has been obtained from tests conducted onboard the International Space Station (ISS) and in Johnson Space Center's clinic. Astronauts undergo a special type of auditory test called an On-Orbit Hearing Assessment (OOHA), which monitors hearing function while crewmembers are exposed to noise and microgravity during long-duration spaceflight. Data needed to be formatted to assist the Audiologist in studying, analyzing and reporting OOHA results from all ISS missions, with comparison to conventional preflight and post-flight audiometric test results of crewmembers. Orbital debris is the #1 threat to manned spacecraft; therefore NASA is investing in different measurement techniques to acquire information on orbital debris. These measurements are taken with telescopes in different parts of the world to acquire brightness variations over time, from which size, rotation rates and material information can be determined for orbital debris. Currently many assumptions are taken to resolve size and material from observed brightness, therefore a laboratory (Optical Measurement Center) is used to simulate the space environment and acquire information of known targets suited to best model the orbital debris population. In the Orbital Debris Program Office (ODPO) telescopic data were acquired and analyzed to better assess the orbital debris population.

  3. Review of the partitioning of chemicals into different plastics: Consequences for the risk assessment of marine plastic debris

    NARCIS (Netherlands)

    O'Connor, I.A.; Golsteijn, L.; Hendriks, A.J.

    2016-01-01

    Marine plastic debris are found worldwide in oceans and coastal areas. They degrade only slowly and contain chemicals added during manufacture or absorbed from the seawater. Therefore, they can pose a long-lasting contaminant source and potentially transfer chemicals to marine organisms when

  4. Cascading Effects of Canopy Opening and Debris Deposition from a Large-Scale Hurricane Experiment in a Tropical Rain Forest

    Science.gov (United States)

    Aaron B. Shiels; Grizelle Gonzalez; D. Jean Lodge; Michael R Willig; Jess K. Zimmerman

    2015-01-01

    Intense hurricanes disturb many tropical forests, but the key mechanisms driving post-hurricane forest changes are not fully understood. In Puerto Rico, we used a replicated factorial experiment to determine the mechanisms of forest change associated with canopy openness and organic matter (debris) addition. Cascading effects from canopy openness accounted for...

  5. Impact of marine debris on Antarctic fur seals Arctocephalus gazella at Cape Shirreff: diet dependent ingestion and entanglement

    NARCIS (Netherlands)

    Bravo Rebolledo, Elisa; Franeker, van J.A.

    2015-01-01

    For several decades it has been known that plastics in the marine environment can harm marine organisms, most visibly birds, turtles and mammals (Shomura and Yoshida, 1985). These animals can become entangled in this synthetic debris and can ingest macro- and micro-plastics. Recently, increased

  6. Floating debris in the Mediterranean Sea.

    Science.gov (United States)

    Suaria, Giuseppe; Aliani, Stefano

    2014-09-15

    Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km(2) and mean abundances of 24.9 AMD items/km(2) and 6.9 NMD items/km(2) across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km(2)) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (<6.3 items/km(2)) were observed in the Central Tyrrhenian and in the Sicilian Sea. All the other areas had mean densities ranging from 10.9 to 30.7 items/km(2). According to our calculations, more than 62 million macro-litter items are currently floating on the surface of the whole Mediterranean basin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. A PRIMER ON UNIFYING DEBRIS DISK MORPHOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eve J.; Chiang, Eugene, E-mail: evelee@berkeley.edu, E-mail: echiang@astro.berkeley.edu [Department of Astronomy, University of California Berkeley, Berkeley, CA 94720-3411 (United States)

    2016-08-20

    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.

  8. A PRIMER ON UNIFYING DEBRIS DISK MORPHOLOGIES

    International Nuclear Information System (INIS)

    Lee, Eve J.; Chiang, Eugene

    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 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.

  9. 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.

  10. 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.

  11. Ingestion of marine debris by the White-chinned Petrel (Procellaria aequinoctialis): Is it increasing over time off southern Brazil?

    Science.gov (United States)

    Petry, Maria V; Benemann, Victória R F

    2017-04-15

    Seabirds are amongst the most affected organisms by plastic pollution worldwide. Ingestion of marine debris has been reported in at least 122 species, and owing to the increasing global production and persistence of these anthropogenic materials within the marine environment, it is expected to be a growing problem to the marine fauna. Here we report evidence of an increasing frequency in marine debris ingestion and a decrease in the amount of plastic pellets ingested by White-chinned Petrels attending south Brazilian waters during the last three decades. Future studies comprising large temporal scales and large sample sizes are needed to better understand the trends of marine debris ingestion by seabirds. We expect our findings to highlight the need for prevention policies and mitigation measures to reduce the amount of solid litter in the oceans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Modeling the fate and transport of plastic debris in freshwaters

    NARCIS (Netherlands)

    Kooi, Merel; Besseling, Ellen; Kroeze, Carolien; Wenzel, van Annemarie P.; Koelmans, Albert A.

    2018-01-01

    Contamination with plastic debris has been recognized as one of today’s major environmental quality problems. Because most of the sources are land based, concerns are increasingly focused on the freshwater and terrestrial environment. Fate and transport models for plastic debris can complement

  13. Dust and Debris Tolerant Dual Poppet Valve Connector

    Science.gov (United States)

    Townsend, III, Ivan I. (Inventor); Mueller, Robert P. (Inventor); Bastin, Gary L. (Inventor); Carlson, Jeffrey W. (Inventor); Murtland, Kevin A. (Inventor)

    2017-01-01

    A debris exclusion and removal apparatus for connectors which have a dual-poppet value configuration containing a pressurized substance. Coupling of the female and male connectors causes the poppet valve to eject a cleaning substance which will eliminate debris from the male connector prior to mating with the female connector.

  14. Marine Debris Clean-Ups as Meaningful Science Learning

    Science.gov (United States)

    Stepath, Carl M.; Bacon, Joseph Scott

    2010-01-01

    This seven to eight week hands-on Marine Debris Clean-up Project used a service project to provide an introduction of marine science ecology, watershed interrelationships, the scientific method, and environmental stewardship to 8th grade middle school students. It utilized inquiry based learning to introduce marine debris sources and impacts to…

  15. Frequency and initiation of debris flows in Grand Canyon, Arizona

    Science.gov (United States)

    Griffiths, Peter G.; Webb, Robert H.; Melis, Theodore S.

    2004-12-01

    Debris flows from 740 tributaries transport sediment into the Colorado River in Grand Canyon, Arizona, creating rapids that control its longitudinal profile. Debris flows mostly occur when runoff triggers failures in colluvium by a process termed "the fire hose effect." Debris flows originate from a limited number of geologic strata, almost exclusively shales or other clay-rich, fine-grained formations. Observations from 1984 through 2003 provide a 20 year record of all debris flows that reached the Colorado River in Grand Canyon, and repeat photography provides a 100 year record of debris flows from 147 tributaries. Observed frequencies are 5.1 events/year from 1984 to 2003, and historic frequencies are 5.0 events/year from 1890 to 1983. Logistic regression is used to model historic frequencies based on drainage basin parameters observed to control debris flow initiation and transport. From 5 to 7 of the 16 parameters evaluated are statistically significant, including drainage area, basin relief, and the height of and gradient below debris flow source areas, variables which reflect transport distance and potential energy. The aspect of the river channel, which at least partially reflects storm movement within the canyon, is also significant. Model results are used to calculate the probability of debris flow occurrence at the river over a century for all 740 tributaries. Owing to the variability of underlying geomorphic controls, the distribution of this probability is not uniform among tributaries of the Colorado River in Grand Canyon.

  16. 33 CFR 209.160 - The California Debris Commission.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false The California Debris Commission..., DEPARTMENT OF DEFENSE ADMINISTRATIVE PROCEDURE § 209.160 The California Debris Commission. Section 1 of the... Commission, consisting of three officers of the Corps of Engineers, to regulate under the supervision of the...

  17. Marine debris in harbour porpoises and seals from German waters.

    Science.gov (United States)

    Unger, B; Herr, H; Benke, H; Böhmert, M; Burkhardt-Holm, P; Dähne, M; Hillmann, M; Wolff-Schmidt, K; Wohlsein, P; Siebert, U

    2017-09-01

    Records of marine debris in and attached to stranded harbour porpoises (Phocoena phocoena), harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) were studied comprising information on 6587 carcasses collected along the German coast between 1990 and 2014, the decomposition state allowed for necropsy in 1622 cases. Marine debris items were recorded in 31 carcasses including 14 entanglements (5 harbour porpoises, 6 harbour seals, 3 grey seals) and 17 cases of ingestion (4 harbour porpoises, 10 harbour seals, 3 grey seals). Objects comprised general debris (35.1%) and fishing related debris (64.9%). Injuries associated with marine debris included lesions, suppurative ulcerative dermatitis, perforation of the digestive tract, abscessation, suppurative peritonitis and septicaemia. This study is the first investigation of marine debris findings in all three marine mammal species from German waters. It demonstrates the health impacts marine debris can have, including severe suffering and death. The results provide needed information on debris burdens in the North and Baltic Seas for implementing management directives, such as the Marine Strategy Framework Directive (MSFD). Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Tracking Debris Shed by a Space-Shuttle Launch Vehicle

    Science.gov (United States)

    Stuart, Phillip C.; Rogers, Stuart E.

    2009-01-01

    The DEBRIS software predicts the trajectories of debris particles shed by a space-shuttle launch vehicle during ascent, to aid in assessing potential harm to the space-shuttle orbiter and crew. The user specifies the location of release and other initial conditions for a debris particle. DEBRIS tracks the particle within an overset grid system by means of a computational fluid dynamics (CFD) simulation of the local flow field and a ballistic simulation that takes account of the mass of the particle and its aerodynamic properties in the flow field. The computed particle trajectory is stored in a file to be post-processed by other software for viewing and analyzing the trajectory. DEBRIS supplants a prior debris tracking code that took .15 minutes to calculate a single particle trajectory: DEBRIS can calculate 1,000 trajectories in .20 seconds on a desktop computer. Other improvements over the prior code include adaptive time-stepping to ensure accuracy, forcing at least one step per grid cell to ensure resolution of all CFD-resolved flow features, ability to simulate rebound of debris from surfaces, extensive error checking, a builtin suite of test cases, and dynamic allocation of memory.

  19. 14 CFR 417.225 - Debris risk analysis.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Debris risk analysis. 417.225 Section 417... 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...

  20. 40 CFR 268.45 - Treatment standards for hazardous debris.

    Science.gov (United States)

    2010-07-01

    ... debris that has been treated using one of the specified extraction or destruction technologies in Table 1... using simple physical or mechanical means; and (ii) Residue from the treatment of hazardous debris is... restrictions 2 A. Extraction Technologies: 1. Physical Extraction a. Abrasive Blasting: Removal of contaminated...

  1. Apical extrusion of debris using reciprocating files and rotary ...

    African Journals Online (AJOL)

    ... the other groups, with the exception of the Typhoon group (P < 0.05). Conclusion: According to our study, all systems caused apical debris extrusion. However, the Reciproc group was associated with less debris extrusion when compared to the other groups. Key words: Apical extrusion, endodontics, single file systems ...

  2. Mapping debris flow susceptibility using analytical network process ...

    Indian Academy of Sciences (India)

    Evangelin Ramani Sujatha

    2017-11-23

    Nov 23, 2017 ... Major loss of plantation land was reported in the 2014 Octo- ber event in Vadakaunchi village. Information on this debris flow was collected from the local res- idents and a site inspection was subsequently carried out to assess the damage. Though large debris flow events that affect the major roads are rare ...

  3. Database Driven 6-DOF Trajectory Simulation for Debris Transport Analysis

    Science.gov (United States)

    West, Jeff

    2008-01-01

    Debris mitigation and risk assessment have been carried out by NASA and its contractors supporting Space Shuttle Return-To-Flight (RTF). As a part of this assessment, analysis of transport potential for debris that may be liberated from the vehicle or from pad facilities prior to tower clear (Lift-Off Debris) is being performed by MSFC. This class of debris includes plume driven and wind driven sources for which lift as well as drag are critical for the determination of the debris trajectory. As a result, NASA MSFC has a need for a debris transport or trajectory simulation that supports the computation of lift effect in addition to drag without the computational expense of fully coupled CFD with 6-DOF. A database driven 6-DOF simulation that uses aerodynamic force and moment coefficients for the debris shape that are interpolated from a database has been developed to meet this need. The design, implementation, and verification of the database driven six degree of freedom (6-DOF) simulation addition to the Lift-Off Debris Transport Analysis (LODTA) software are discussed in this paper.

  4. 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...

  5. ABB. CASE's GUARDIANTM Debris Resistant Fuel Assembly Design

    International Nuclear Information System (INIS)

    Dixon, D. J.; Wohlsen, W. D.

    1992-01-01

    ABB CE's experience, that 72% of all recent fuel-rod failures are caused by debris fretting, is typical. In response to this problem, ABB Combustion Engineering began supplying in the late 1980s fuel assemblies with a variety of debris resistant features, including both long-end caps and small flow holes. Now ABB CAE has developed an advanced debris resistant design concept, GUARDIAN TM , which has the advantage of capturing and retaining more debris than other designs, while displacing less plenum or active fuel volume than the long end-cap design. GUARDIAN TM design features have now been implemented into four different assembly designs. ABB CASE's GUARDIAN TM fuel assembly is an advanced debris-resistant design which has both superior filtering performance and uniquely, excellent debris retention, Retention effectively removes the debris from circulation in the coolant so that it is not able to threaten the fuel again. GUARDIAN TM features have been incorporated into four ABB. CAE fuel assembly designs. These assemblies are all fully compatible with the NSLS, and full-batch operation with GUARDIAN TM began in 1992. The number of plants of both CAE and non-CAE design which accept GUARDIAN TM for debris protection is expected to grow significantly during the next few years

  6. Contrasting mass-wasting activity in two debris flow-dominated catchments of the Venosta Valley/Vinschgau (Italy): 1945-2014

    Science.gov (United States)

    Lazzarini, Simone; Brardinoni, Francesco; Draganits, Erich; Cavalli, Marco

    2015-04-01

    combines zones with colluvial transport regimes with areas in which fluvial transport prevails, whereas Plaies is essentially dominated by mass-wasting processes strongly controlled by the dynamics of the overhanging Ortler Glacier. Further, Cengles is a supply-limited system, since there the occurrence of debris flows is strongly controlled by in-channel sediment evacuation and recharge cycles that interact with the overcoming of variable hydrometeorological thresholds. In contrast, Plaies is a transport-limited resulting from the almost unlimited availability of loose, mainly glacigenic material that can be mobilized. The debris-flow activity in Plaies is strongly controlled by a combination of hydrometeorological forcing and glacier dynamics. This work is part of SedAlp (www.sedalp.eu), a project funded through the Alpine Space Programme.

  7. TRANSPORT CHARACTERISTICS OF SELECTED PWR LOCA GENERATED DEBRIS

    International Nuclear Information System (INIS)

    MAJI, A. K.; MARSHALL, B.

    2000-01-01

    In the unlikely event of a Loss of Coolant Accident (LOCA) in a pressurized water reactor (PWR), break jet impingement would dislodge thermal insulation FR-om nearby piping, as well as other materials within the containment, such as paint chips, concrete dust, and fire barrier materials. Steam/water flows induced by the break and by the containment sprays would transport debris to the containment floor. Subsequently, debris would likely transport to and accumulate on the suction sump screens of the emergency core cooling system (ECCS) pumps, thereby potentially degrading ECCS performance and possibly even failing the ECCS. In 1998, the U. S. Nuclear Regulatory Commission (NRC) initiated a generic study (Generic Safety Issue-191) to evaluate the potential for the accumulation of LOCA related debris on the PWR sump screen and the consequent loss of ECCS pump net positive suction head (NPSH). Los Alamos National Laboratory (LANL), supporting the resolution of GSI-191, was tasked with developing a method for estimating debris transport in PWR containments to estimate the quantity of debris that would accumulate on the sump screen for use in plant specific evaluations. The analytical method proposed by LANL, to predict debris transport within the water that would accumulate on the containment floor, is to use computational fluid dynamics (CFD) combined with experimental debris transport data to predict debris transport and accumulation on the screen. CFD simulations of actual plant containment designs would provide flow data for a postulated accident in that plant, e.g., three-dimensional patterns of flow velocities and flow turbulence. Small-scale experiments would determine parameters defining the debris transport characteristics for each type of debris. The containment floor transport methodology will merge debris transport characteristics with CFD results to provide a reasonable and conservative estimate of debris transport within the containment floor pool and

  8. USA Space Debris Environment, Operations, and Research Updates

    Science.gov (United States)

    Liou, J.-C.

    2018-01-01

    Space Missions in 2017 Earth Satellite Population Collision Avoidance Maneuvers Post mission Disposal of U.S.A. Spacecraft Space Situational Awareness (SSA) and the Space Debris Sensor (SDS) A total of 86 space launches placed more than 400 spacecraft into Earth orbits during 2017, following the trend of increase over the past decade NASA has established conjunction assessment processes for its human spaceflight and uncrewed spacecraft to avoid accidental collisions with objects tracked by the U.S. Space Surveillance Network - NASA also assists other U.S. government spacecraft owners with conjunction assessments and subsequent maneuvers The ISS has conducted 25 debris collision avoidance maneuvers since 1999 - None in 2016-2017, but an ISS visiting vehicle had one collision avoidance maneuver in 2017 During 2017 NASA executed or assisted in the execution of 21 collision avoidance maneuvers by uncrewed spacecraft - Four maneuvers were conducted to avoid debris from Fengyun-1C - Two maneuvers were conducted to avoid debris from the collision of Cosmos 2251 and Iridium 33 - One maneuver was conducted to avoid the ISS NASA has established conjunction assessment processes for its human spaceflight and uncrewed spacecraft to avoid accidental collisions with objects tracked by the U.S. Space Surveillance Network - NASA also assists other U.S. government spacecraft owners with conjunction assessments and subsequent maneuvers The ISS has conducted 25 debris collision avoidance maneuvers since 1999 - None in 2016-2017, but an ISS visiting vehicle had one collision avoidance maneuver in 2017 During 2017 NASA executed or assisted in the execution of 21 collision avoidance maneuvers by uncrewed spacecraft - Four maneuvers were conducted to avoid debris from Fengyun-1C - Two maneuvers were conducted to avoid debris from the collision of Cosmos 2251 and Iridium 33 The 2014-15 NASA Engineering and Safety Center (NESC) study on the micrometeoroid and orbital debris (MMOD

  9. 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.

  10. The impact of debris on the Florida manatee

    Science.gov (United States)

    Beck, C.A.; Barros, N.B.

    1991-01-01

    The endangered Florida manatee ingests debris while feeding. From 1978 through 1986, 439 salvaged manatees were examined. Debris was in the gastrointestinal tract of 63 (14.4%) and four died as a direct result of debris ingestion. Monofilament fishing line was the most common debris found (N=49). Plastic bags, string, twine, rope, fish hooks, wire, paper, cellophane, synthetic sponges, rubber bands, and stockings also were recovered. Entanglement in lines and nets killed 11 manatees from 1974 through 1985. Numerous free-ranging manatees have missing or scarred flippers from entanglements, or debris still encircling one or both flippers. We recommend local cleanups, education of the public, and fishing restrictions in high use areas to significantly reduce harm to manatees.

  11. Bacteria at glacier surfaces: microbial community structures in debris covered glaciers and cryoconites in the Italian Alps

    Science.gov (United States)

    Azzoni, Roberto; Franzetti, Andrea; Ambrosini, Roberto; D'Agata, Carlo; Senese, Antonella; Minora, Umberto; Tagliaferri, Ilario; Diolaiuti, Guglielmina

    2014-05-01

    Supraglacial debris has an important role in the glacier energy budget and has strong influence on the glacial ecosystem. Sediment derives generally from rock inputs from nesting rockwalls and are abundant and continuous at the surface of debris-covered glaciers (i.e. DCGs; glaciers where the ablation area is mainly covered by rock debris) and sparse and fine on debris-free glaciers (DFGs). Recently, evidence for significant tongue darkening on retreating debris-free glaciers has been drawing increasing attention. Fine particles, the cryoconite, are locally abundant and may form cryoconite holes that are water-filled depressions on the surface of DFGs that form when a thin layer of cryoconite is heated by the sun and melts the underlying ice. There is increasing evidence that cryoconite holes also host highly diverse microbial communities and can significantly contribute to global carbon cycle. However, there is almost no study on microbial communities of the debris cover of DCGs and there is a lack of data from the temporal evolution of the microbial communities in the cryoconites. To fill these gaps in our knowledge we characterized the supraglacial debris of two Italian DCGs and we investigated the temporal evolution of microbial communities on cryoconite holes in DFG. We used the Illumina technology to analyse the V5 and V6 hypervariable regions of the bacterial 16S rRNA gene amplified from samples collected distances from the terminus of two DCGs (Miage and Belvedere Glaciers - Western Italian Alps). Heterotrophic taxa dominated bacterial communities, whose structure changed during downwards debris transport. Organic carbon of these recently exposed substrates therefore is probably provided more by allochthonous deposition of organic matter than by primary production by autotrophic organisms. We used ARISA fingerprinting and quantitative PCR to describe the structure and the evolution of the microbial communities and to estimate the number of the total

  12. Marine plastic debris emits a keystone infochemical for olfactory foraging seabirds.

    Science.gov (United States)

    Savoca, Matthew S; Wohlfeil, Martha E; Ebeler, Susan E; Nevitt, Gabrielle A

    2016-11-01

    Plastic debris is ingested by hundreds of species of organisms, from zooplankton to baleen whales, but how such a diversity of consumers can mistake plastic for their natural prey is largely unknown. The sensory mechanisms underlying plastic detection and consumption have rarely been examined within the context of sensory signals driving marine food web dynamics. We demonstrate experimentally that marine-seasoned microplastics produce a dimethyl sulfide (DMS) signature that is also a keystone odorant for natural trophic interactions. We further demonstrate a positive relationship between DMS responsiveness and plastic ingestion frequency using procellariiform seabirds as a model taxonomic group. Together, these results suggest that plastic debris emits the scent of a marine infochemical, creating an olfactory trap for susceptible marine wildlife.

  13. Risk assessment of debris flow hazards in natural slope

    Science.gov (United States)

    Choi, Junghae; Chae, Byung-gon; Liu, Kofei; Wu, Yinghsin

    2016-04-01

    The study area is located at north-east part of South Korea. Referring to the map of landslide sus-ceptibility (KIGAM, 2009) from Korea Institute of Geoscience and Mineral Resources (KIGAM for short), there are large areas of potential landslide in high probability on slope land of mountain near the study area. Besides, recently some severe landslide-induced debris flow hazards occurred in this area. So this site is convinced to be prone to debris flow haz-ards. In order to mitigate the influence of hazards, the assessment of potential debris flow hazards is very important and essential. In this assessment, we use Debris-2D, debris flow numerical program, to assess the potential debris flow hazards. The worst scenario is considered for simulation. The input mass sources are determined using landslide susceptibility map. The water input is referred to the daily accumulative rainfall in the past debris flow event in study area. The only one input material property, i.e. yield stress, is obtained using calibration test. The simulation results show that the study area has po-tential to be impacted by debris flow. Therefore, based on simulation results, to mitigate debris flow hazards, we can propose countermeasures, including building check dams, constructing a protection wall in study area, and installing instruments for active monitoring of debris flow hazards. Acknowledgements:This research was supported by the Public Welfare & Safety Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2012M3A2A1050983)

  14. Effects of 1997 debris floods in two Klamath Mountain streams: A large woody debris mass-balance approach

    Science.gov (United States)

    Zackary J. Mondry; Susan J. Hilton

    2000-01-01

    Large landslides and debris flows in January 1997 produced contrasting downstream debris flood effects in two adjacent Northern California Klamath Mountain streams. Valley morphology and riparian forests were examined on post-flood 1:3000 air photos along two approximately 8 km survey reaches.

  15. Determining the quantity and character of carotid artery embolic debris by electron microscopy and energy dispersive spectroscopy.

    Science.gov (United States)

    DeRubertis, Brian G; Chaer, Rabih A; Gordon, Ronald; Bell, Heather; Hynecek, Robert L; Pieracci, Fred M; Karwowski, John; Kent, K Craig; Faries, Peter L

    2007-04-01

    Carotid artery angioplasty and stenting (CAS) is now routinely performed with embolic protection devices, yet little is known about the compositional characteristics of the captured embolic debris and whether the type or quantity of debris correlates with patient, lesion, or operator characteristics. This study examined the embolic debris generated during CAS using electron microscopy and energy dispersive spectroscopy (EDS) for symptomatic and asymptomatic patients. Between 2003 and 2005, CAS for carotid stenosis was performed in 175 patients. Cerebral protection devices were used in all but three cases. Sixty-four consecutive unselected microporous filters from procedures performed by a single vascular surgeon were obtained for analysis. Captured particulate debris within the protection devices was quantified (number and mean size of particles) by light microscopy for all filters. Twenty protection devices (9 symptomatic, 11 asymptomatic patients) were processed for electron microscopy and EDS to assess morphology, cellular composition, and calcium content of debris. Captured particulate matter was present in 49 filters (77%) and included particles measuring 200 to 500 mum in 72%, 500 to 1000 mum in 53%, and >1000 mum in 33%. The mean number of captured particles was 6.9, and mean size was 248 +/- 150 mum. Univariate analysis revealed that sequential patient cohort and filter type were correlated with the number (but not size) of captured particles. The number of particles significantly decreased after the first cohort of 20 patients (11.5 particles) compared with the second (5.0 particles, P = .023) and third (5.2 particles, P = .029) cohorts. The type of captured debris ranged from sheets of damaged red blood cells without other components to clumps of recently activated platelets with early fibrin crosslinking to plaque debris coated with well-organized coalescing areas of platelet thrombus. Platelet activation was more common in symptomatic patients (78

  16. Systems and Sensors for Debris-flow Monitoring and Warning

    Directory of Open Access Journals (Sweden)

    Lorenzo Marchi

    2008-04-01

    Full Text Available Debris flows are a type of mass movement that occurs in mountain torrents. They consist of a high concentration of solid material in water that flows as a wave with a steep front. Debris flows can be considered a phenomenon intermediate between landslides and water floods. They are amongst the most hazardous natural processes in mountainous regions and may occur under different climatic conditions. Their destructiveness is due to different factors: their capability of transporting and depositing huge amounts of solid materials, which may also reach large sizes (boulders of several cubic meters are commonly transported by debris flows, their steep fronts, which may reach several meters of height and also their high velocities. The implementation of both structural and nonstructural control measures is often required when debris flows endanger routes, urban areas and other infrastructures. Sensor networks for debris-flow monitoring and warning play an important role amongst non-structural measures intended to reduce debris-flow risk. In particular, debris flow warning systems can be subdivided into two main classes: advance warning and event warning systems. These two classes employ different types of sensors. Advance warning systems are based on monitoring causative hydrometeorological processes (typically rainfall and aim to issue a warning before a possible debris flow is triggered. Event warning systems are based on detecting debris flows when these processes are in progress. They have a much smaller lead time than advance warning ones but are also less prone to false alarms. Advance warning for debris flows employs sensors and techniques typical of meteorology and hydrology, including measuring rainfall by means of rain gauges and weather radar and monitoring water discharge in headwater streams. Event warning systems use different types of sensors, encompassing ultrasonic or radar gauges, ground vibration sensors, videocameras, avalanche

  17. Material Density Distribution of Small Debris in Earth Orbit

    Science.gov (United States)

    Krisko, P. H.; Xu, Y.-l.; Opiela, J. N.; Hill, N. M.; Matney, M. J.

    2008-01-01

    Over 200 spacecraft and rocket body breakups in Earth orbit have populated that regime with debris fragments in the sub-micron through meter size range. Though the largest debris fragments can cause significant collisional damage to active (operational) spacecraft, these are few and trackable by radar. Fragments on the order of a millimeter to a centimeter in size are as yet untrackable. But this smaller debris can result in damage to critical spacecraft systems and, under the worst conditions, fragmenting collision events. Ongoing research at the NASA Orbital Debris Program Office on the sources of these small fragments has focused on the material components of spacecraft and rocket bodies and on breakup event morphology. This has led to fragment material density estimates, and also the beginnings of shape categorizations. To date the NASA Standard Breakup Model has not considered specific material density distinctions of small debris. The basis of small debris in that model is the fourth hypervelocity impact event of the Satellite Orbital Debris Characterization Impact Test (SOCIT) series. This test targeted a flight-ready, U.S. Transit navigation satellite with a solid aluminum sphere impactor. Results in this event yield characteristic length (size) and area-to-mass distributions of fragments smaller than 10 cm in the NASA model. Recent re-analysis of the SOCIT4 small fragment dataset highlighted the material-specific characteristics of metals and non-metals. Concurrent analysis of Space Shuttle in-situ impact data showed a high percentage of aluminum debris in shuttle orbit regions. Both analyses led to the definition of three main on-orbit debris material density categories -low density ( 6 g/cc). This report considers the above studies in an explicit extension of the NASA Standard Breakup Model where separate material densities for debris are generated and these debris fragments are propagated in Earth orbit. The near Earth environment is thus parameterized

  18. Safe disposal and recycling of water disaster debris in pakistan

    International Nuclear Information System (INIS)

    Latif, A.

    2014-01-01

    Depending upon the nature, the disaster may produce large masses of debris. Waste masses from single disaster integrate to larger magnitude annually. This will ultimately causes the extra work load on personnel and reflects the poor existing debris management facilities. Besides, it will take longer time to rehabilitate the debris exaggerated regions. The study focuses on 2 main cases of disaster i.e. earthquake of 2005 and flood of 2010 in Pakistan. Complete analysis involve two stages: the first stage involve development of disaster and disaster debris effects guidance whereas the second stage involves the development of set of criteria to make efficient environment and positive impacts of successful debris managing scheme. Such principles were employed to evaluate efficiency of debris managing scheme for detailed analysis. The discussion of the detailed analysis depicts methodology which assists the disaster managers, planners and researcher to simply multitude of work. Moreover, the disaster and disaster debris influence direction, the effect evaluation criterion and managing criteria have been established having the effect they can be virtually put into service for prospect debris managing scheme, planning and retort. With respect to character and strictness, calamity may make high magnitude of waste. By keeping in view the precedent calamities in the United States (US), concluded that in few situations produced waste masses approximately five to fifteen times more than yearly waste production rate from a single occasion. Same results were revealed by subsequent tsunami of Indian Ocean. Such kind of large masses may effects the existing solid debris management system and human resources. Major disaster yields large masses of debris in few hours or sometimes even in minutes. The volume of disaster debris depends upon the magnitude of trees ball up, indemnity to houses, business, services etc. The disaster remaining may be equally large in metropolitan and non

  19. A real two-phase submarine debris flow and tsunami

    International Nuclear Information System (INIS)

    Pudasaini, Shiva P.; Miller, Stephen A.

    2012-01-01

    The general two-phase debris flow model proposed by Pudasaini is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model, which includes three fundamentally new and dominant physical aspects such as enhanced viscous stress, virtual mass, and generalized drag (in addition to buoyancy), constitutes the most generalized two-phase flow model to date. The advantage of this two-phase debris flow model over classical single-phase, or quasi-two-phase models, is that the initial mass can be divided into several parts by appropriately considering the solid volume fraction. These parts include a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This innovative formulation provides an opportunity, within a single framework, to simultaneously simulate the sliding debris (or landslide), the water lake or ocean, the debris impact at the lake or ocean, the tsunami generation and propagation, the mixing and separation between the solid and fluid phases, and the sediment transport and deposition process in the bathymetric surface. Applications of this model include (a) sediment transport on hill slopes, river streams, hydraulic channels (e.g., hydropower dams and plants); lakes, fjords, coastal lines, and aquatic ecology; and (b) submarine debris impact and the rupture of fiber optic, submarine cables and pipelines along the ocean floor, and damage to offshore drilling platforms. Numerical simulations reveal that the dynamics of debris impact induced tsunamis in mountain lakes or oceans are fundamentally different than the tsunami generated by pure rock avalanches and landslides. The analysis includes the generation, amplification and propagation of super tsunami waves and run-ups along coastlines, debris slide and deposition at the bottom floor, and debris shock waves. It is observed that the

  20. Debris disks in open stellar clusters

    Science.gov (United States)

    Gorlova, Nadiya Igorivna

    Indirect searches for planets (such as radial velocity studies) show that their formation may be quite common. The planets are however too small and faint to be seen against the glare of their host stars; therefore, their direct detection is limited to the nearest systems. Alternatively one can study planets by studying their "by-product"---dust. We see raw material available for planets around young stars, and debris dust around old stars betraying planet-induced activity. Dust has a larger surface area per unit mass compared with a large body; it can be spread over a larger solid angle, intercepting more starlight and emitting much more light via reprocessing. By studying dusty disks we can infer the presence of planets at larger distances. Here we present results of a survey conducted with the Spitzer Space Telescope of debris disks in three open clusters. With ages of 30--100 Myrs, these clusters are old enough that the primordial dust should have accreted into planetesimals, fallen onto the star, or been blown away due to a number of physical processes. The dust we observe must come from collisions or sublimation of larger bodies. The purpose of this study is to investigate the dust evolution in the terrestrial planet zone, analogous to the Zodiacal cloud in our Solar system. We are most sensitive to this zone because the peak of a 125 K black body radiation falls into the primary pass-band of our survey---24mm. We investigate the fraction and amount of the infra-red excesses around intermediate- to solar-mass stars in open stellar clusters with well defined ages. The results are analyzed in the context of disk studies at other wavelengths and ages, providing an understanding of the time-scale for disk dissipation and ultimately planet building and frequency.

  1. Dissolved carbon and nitrogen leaching following variable logging-debris retention and competing-vegetation control in Douglas-fir plantations of western Oregon and Washington

    Science.gov (United States)

    Robert A. Slesak; Stephen H. Schoenholtz; Timothy B. Harrington; Brian D. Strahm

    2009-01-01

    We examined the effect of logging-debris retention and competing-vegetation control (CCC, initial or annual applications) on dissolved organic carbon (DOC), dissolved organic nitrogen, and nitrate-N leaching to determine the relative potential of these practices to contribute to soil C and N loss at two contrasting sites. Annual CVC resulted in higher soil water...

  2. Marine debris in five national parks in Alaska.

    Science.gov (United States)

    Polasek, L; Bering, J; Kim, H; Neitlich, P; Pister, B; Terwilliger, M; Nicolato, K; Turner, C; Jones, T

    2017-04-15

    Marine debris is a management issue with ecological and recreational impacts for agencies, especially on remote beaches not accessible by road. This project was implemented to remove and document marine debris from five coastal National Park Service units in Alaska. Approximately 80km of coastline were cleaned with over 10,000kg of debris collected. Marine debris was found at all 28 beaches surveyed. Hard plastics were found on every beach and foam was found at every beach except one. Rope/netting was the next most commonly found category, present at 23 beaches. Overall, plastic contributed to 60% of the total weight of debris. Rope/netting (14.6%) was a greater proportion of the weight from all beaches than foam (13.3%). Non-ferrous metal contributed the smallest amount of debris by weight (1.7%). The work forms a reference condition dataset of debris surveyed in the Western Arctic and the Gulf of Alaska within one season. Copyright © 2017. Published by Elsevier Ltd.

  3. Development of fuel debris cutting technique by laser gouging

    International Nuclear Information System (INIS)

    Nomura, Kota; Shiihara, Katsunori; Chida, Itaru; Kono, Wataru; Suzuki, Jun

    2015-01-01

    Development of damaged fuel debris cutting technique in Fukushima Daiichi nuclear plant is one of the important issues for the defueling operations such as removing from the reactor, handling and storage, and so on. Previous knowledge in the Three Mile Island Unit 2 (TMI-2) nuclear plant accident is reported that fuel debris was made of uranium oxides, stainless steel, zircaloy and so on. Therefore, it is difficult to cut fuel debris by machine processing. Laser cutting is convenient to cut complex materials. However, it is difficult to know the thickness of fuel debris in advance, so it is hard to apply the conventional laser cutting method. In this study, we have been developed the cutting technique for fuel debris by using laser gouging method. Test pieces that simulate fuel debris ware fabricated by embedding ceramic pellet on stainless steel. Laser gouging test was performed by cutting surface of the test pieces with high power fiber laser, whose maximum irradiation power was 10 kW. According to the test result, laser gouging process has the ability to grind the simulated fuel debris under atmospheric condition. In addition, same kind of cutting effect could be performed underwater. (author)

  4. Active Removal of Large Debris: Electrical Propulsion Capabilities

    Science.gov (United States)

    Billot Soccodato, Carole; Lorand, Anthony; Perrin, Veronique; Couzin, Patrice; FontdecabaBaig, Jordi

    2013-08-01

    The risk for current operational spacecraft or future market induced by large space debris, dead satellites or rocket bodies, in Low Earth Orbit has been identified several years ago. Many potential solutions and architectures are traded with a main objective of reducing cost per debris. Based on cost consideration, specially driven by launch cost, solutions constructed on multi debris capture capacities seem to be much affordable The recent technologic evolutions in electric propulsion and solar power generation can be used to combine high potential vehicles for debris removal. The present paper reports the first results of a study funded by CNES that addresses full electric solutions for large debris removal. Some analysis are currently in progress as the study will end in August. It compares the efficiency of in-orbit Active Removal of typical debris using electric propulsion The electric engine performances used in this analysis are demonstrated through a 2012/2013 PPS 5000 on-ground tests campaign. The traded missions are based on a launch in LEO, the possible vehicle architectures with capture means or contact less, the selection of deorbiting or reorbiting strategy. For contact less strategy, the ion-beam shepherd effect towards the debris problematic will be addressed. Vehicle architecture and performance of the overall system will be stated, showing the adequacy and the limits of each solution.

  5. Recent Developments in Space Debris Mitigation Policy and Practices

    Science.gov (United States)

    Johnson, Nicholas L.

    2006-01-01

    In recent years, emphasis has shifted from national efforts to control the space debris population to international ones. Here, too, great progress has been made, most notably by the Inter-Agency Space Debris Coordination Committee (IADC) and the Committee on the Peaceful Uses of Outer Space (COPUOS) of the United Nations. Today, a firm international consensus is rapidly building on the principal space debris mitigation measures. The IADC is an association of the space agencies of ten countries (China, France, Germany, India, Italy, Japan, Russia, Ukraine, the United Kingdom, and the United States) and the European Space Agency, representing 17 countries of which four (France, Germany, Italy, and the United Kingdom) are also full IADC members. At the 17th meeting of the IADC in October 1999, a new Action Item (AI 17.2) was adopted to develop a set of consensus space debris mitigation guidelines. The purpose of the activity was to identify the most valuable space debris mitigation measures and to reach an international agreement on common directives. The IADC Space Debris Mitigation Guidelines (www.iadc-online.org/index.cgi?item=docs_pub) were formally adopted in October 2002 during the Second World Space Congress in Houston, Texas. Two years later a companion document, entitled Support to the IADC Space Debris Mitigation Guidelines, was completed to provide background and clarification for the guidelines.

  6. On the debris-level origins of adhesive wear.

    Science.gov (United States)

    Aghababaei, Ramin; Warner, Derek H; Molinari, Jean-François

    2017-07-25

    Every contacting surface inevitably experiences wear. Predicting the exact amount of material loss due to wear relies on empirical data and cannot be obtained from any physical model. Here, we analyze and quantify wear at the most fundamental level, i.e., wear debris particles. Our simulations show that the asperity junction size dictates the debris volume, revealing the origins of the long-standing hypothesized correlation between the wear volume and the real contact area. No correlation, however, is found between the debris volume and the normal applied force at the debris level. Alternatively, we show that the junction size controls the tangential force and sliding distance such that their product, i.e., the tangential work, is always proportional to the debris volume, with a proportionality constant of 1 over the junction shear strength. This study provides an estimation of the debris volume without any empirical factor, resulting in a wear coefficient of unity at the debris level. Discrepant microscopic and macroscopic wear observations and models are then contextualized on the basis of this understanding. This finding offers a way to characterize the wear volume in atomistic simulations and atomic force microscope wear experiments. It also provides a fundamental basis for predicting the wear coefficient for sliding rough contacts, given the statistics of junction clusters sizes.

  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. Constraints on Exoplanet System Architectures from Debris Disks

    Science.gov (United States)

    Jang-Condell, Hannah; Chen, Christine H.; Mittal, Tushar; Nesvold, Erika; Kuchner, Marc J.; Manoj, P.; Watson, Dan; Lisse, Carey M.

    2015-12-01

    Debris disks are dusty disks around main sequence stars. Terrestrial planets may be forming in young debris disks with ages structure of debris disks could be an indicator of where planets have formed. We present an analysis of several members of the Scorpius-Centaurus OB Association (Sco Cen) that host both debris disks and planets, including HD 95086, HD 106906, and HD 133803. These objects are about 15-17 Myr old. The thermal emission from the debris disks constrains the locations of the dust. The dust is typically interior to the directly imaged planets in the systems. If additional planets reside in these systems, their locations are constrained by the positions of the dust belts. Many debris disk systems in Sco Cen appear to be two-belt systems. The gap between the belts in each system is a likely location for additional planets. The detection of planets in debris disk systems provide clues about the planet formation process, giving insights into where, when and how planets form.

  9. Styrofoam debris as a potential carrier of mercury within ecosystems.

    Science.gov (United States)

    Graca, Bożena; Bełdowska, Magdalena; Wrzesień, Patrycja; Zgrundo, Aleksandra

    2014-02-01

    The present paper falls within the trend of research into interactions between various pollutants emitted anthropogenically into the environment and focuses on mercury and styrofoam debris. The study covers part of the Southern Baltic's drainage area. Apart from styrofoam and beach sand, the research involved mosses, which are bioindicators of atmospheric metal pollution. The research has shown that mercury present in the environment becomes associated with styrofoam debris. The median for mercury concentrations in virgin styrofoam samples (0.23 ng g(-1) dry weight (d.w.)) and in beach sand samples (0.69 ng g(-1) d.w.) was an order of magnitude lower than in the styrofoam debris (5.20 ng g(-1) d.w.). The highest mercury content observed in styrofoam debris (3,863 ng g(-1) d.w.) exceeded the standards for bottom sediment and soil. The binding of mercury to styrofoam debris takes place in water, and presumably also through contact with the ground. A significant role in this process was played by biotic factors, such as the presence of biofilm and abiotic ones, such as solar radiation and the transformations of mercury forms related to it. As a result, mercury content in styrofoam debris underwent seasonal changes, peaking in summertime. Furthermore, the regional changes of mercury content in the studied debris seem to reflect the pollution levels of the environment.

  10. The effects of large beach debris on nesting sea turtles

    Science.gov (United States)

    Fujisaki, Ikuko; Lamont, Margaret M.

    2016-01-01

    A field experiment was conducted to understand the effects of large beach debris on sea turtle nesting behavior as well as the effectiveness of large debris removal for habitat restoration. Large natural and anthropogenic debris were removed from one of three sections of a sea turtle nesting beach and distributions of nests and false crawls (non-nesting crawls) in pre- (2011–2012) and post- (2013–2014) removal years in the three sections were compared. The number of nests increased 200% and the number of false crawls increased 55% in the experimental section, whereas a corresponding increase in number of nests and false crawls was not observed in the other two sections where debris removal was not conducted. The proportion of nest and false crawl abundance in all three beach sections was significantly different between pre- and post-removal years. The nesting success, the percent of successful nests in total nesting attempts (number of nests + false crawls), also increased from 24% to 38%; however the magnitude of the increase was comparably small because both the number of nests and false crawls increased, and thus the proportion of the nesting success in the experimental beach in pre- and post-removal years was not significantly different. The substantial increase in sea turtle nesting activities after the removal of large debris indicates that large debris may have an adverse impact on sea turtle nesting behavior. Removal of large debris could be an effective restoration strategy to improve sea turtle nesting.

  11. An Approach to Predict Debris Flow Average Velocity

    Directory of Open Access Journals (Sweden)

    Chen Cao

    2017-03-01

    Full Text Available Debris flow is one of the major threats for the sustainability of environmental and social development. The velocity directly determines the impact on the vulnerability. This study focuses on an approach using radial basis function (RBF neural network and gravitational search algorithm (GSA for predicting debris flow velocity. A total of 50 debris flow events were investigated in the Jiangjia gully. These data were used for building the GSA-based RBF approach (GSA-RBF. Eighty percent (40 groups of the measured data were selected randomly as the training database. The other 20% (10 groups of data were used as testing data. Finally, the approach was applied to predict six debris flow gullies velocities in the Wudongde Dam site area, where environmental conditions were similar to the Jiangjia gully. The modified Dongchuan empirical equation and the pulled particle analysis of debris flow (PPA approach were used for comparison and validation. The results showed that: (i the GSA-RBF predicted debris flow velocity values are very close to the measured values, which performs better than those using RBF neural network alone; (ii the GSA-RBF results and the MDEE results are similar in the Jiangjia gully debris flow velocities prediction, and GSA-RBF performs better; (iii in the study area, the GSA-RBF results are validated reliable; and (iv we could consider more variables in predicting the debris flow velocity by using GSA-RBF on the basis of measured data in other areas, which is more applicable. Because the GSA-RBF approach was more accurate, both the numerical simulation and the empirical equation can be taken into consideration for constructing debris flow mitigation works. They could be complementary and verified for each other.

  12. Development of a debris flow model in a geotechnical centrifuge

    Science.gov (United States)

    Cabrera, Miguel Angel; Wu, Wei

    2013-04-01

    Debris flows occur in three main stages. At first the initial soil mass, which rests in a rigid configuration, reaches a critic state releasing a finite mass over a failure surface. In the second stage the released mass starts being transported downhill in a dynamic motion. Segregation, erosion, entrainment, and variable channel geometry are among the more common characteristics of this stage. Finally, at the third stage the transported mass plus the mass gained or loosed during the transportation stage reach a flat and/or a wide area and its deposition starts, going back to a rigid configuration. The lack of understanding and predictability of debris flow from the traditional theoretical approaches has lead that in the last two decades the mechanics of debris flows started to be analysed around the world. Nevertheless, the validation of recent numerical advances with experimental data is required. Centrifuge modelling is an experimental tool that allows the test of natural processes under defined boundary conditions in a small scale configuration, with a good level of accuracy in comparison with a full scale test. This paper presents the development of a debris flow model in a geotechnical centrifuge focused on the second stage of the debris flow process explained before. A small scale model of an inclined flume will be developed, with laboratory instrumentation able to measure the pore pressure, normal stress, and velocity path, developed in a scaled debris flow in motion. The model aims to reproduce in a controlled environment the main parameters of debris flow motion. This work is carried under the EC 7th Framework Programme as part of the MUMOLADE project. The dataset and data-analysis obtained from the tests will provide a qualitative description of debris flow motion-mechanics and be of valuable information for MUMOLADE co-researchers and for the debris flow research community in general.

  13. Anthropogenic effect on avalanche and debris flow activity

    Directory of Open Access Journals (Sweden)

    S. A. Sokratov

    2013-01-01

    Full Text Available The paper presents examples of the change in snow avalanches and debris flows activity due to the anthropogenic pressure on vegetation and relief. The changes in dynamical characteristics of selected snow avalanches and debris flows due to the anthropogenic activity are quantified. The conclusion is made that the anthropogenic effects on the snow avalanches and debris flows activity are more pronounced than the possible effects of the climate change. The necessity is expressed on the unavoidable changes of the natural environment as the result of a construction and of use of the constructed infrastructure to be account for in corresponding planning of the protection measures.

  14. FTIR Analyses of Hypervelocity Impact Deposits: DebriSat Tests

    Science.gov (United States)

    2015-03-27

    fiberglass, stainless steel mesh and Kevlar . Debris-LV used a 15 kg target fabricated by Aerospace to simulate a spent upper stage. DebriSat consisted of a...designed to catch the projectile. It consisted of seven bumper panels consisting of fiberglass, stainless steel mesh and Kevlar . Debris-LV used a 15...fabric (#1,2, 4, 5), stainless steel mesh (#3) and Kevlar (#6,7). • No “soft catch “ panels were installed in the chamber. • A witness plate

  15. Global tracking of space debris via CPHD and consensus

    Science.gov (United States)

    Wei, Baishen; Nener, Brett; Liu, Weifeng; Ma, Liang

    2017-05-01

    Space debris tracking is of great importance for safe operation of spacecraft. This paper presents an algorithm that achieves global tracking of space debris with a multi-sensor network. The sensor network has unknown and possibly time-varying topology. A consensus algorithm is used to effectively counteract the effects of data incest. Gaussian Mixture-Cardinalized Probability Hypothesis Density (GM-CPHD) filtering is used to estimate the state of the space debris. As an example of the method, 45 clusters of sensors are used to achieve global tracking. The performance of the proposed approach is demonstrated by simulation experiments.

  16. X-raying the AU Microscopii debris disk

    OpenAIRE

    Schneider, P. C.; Schmitt, J. H. M. M.

    2010-01-01

    AU Mic is a young, nearby X-ray active M-dwarf with an edge-on debris disk. Debris disk are the successors of the gaseous disks usually surrounding pre-main sequence stars which form after the first few Myrs of their host stars' lifetime, when - presumably - also the planet formation takes place. Since X-ray transmission spectroscopy is sensitive to the chemical composition of the absorber, features in the stellar spectrum of AU Mic caused by its debris disk can in principle be detected. The ...

  17. Geomorphic change caused by outburst floods and debris flows at Mount Rainier, Washington, with emphasis on Tahoma Creek valley

    Science.gov (United States)

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

    1994-01-01

    Debris flows have caused rapid geomorphic change in several glacierized drainages on Mount Rainier, Washington. Nearly all of these flows began as glacial outburst floods, then transformed to debris flows by incorporating large masses of sediment in channel reaches where streams have incised proglacial sediments and stagnant glacier ice. This stagnant ice is a relic of advanced glacier positions achieved during the mid-nineteenth century Little Ice Age maximum and the readvance of the 1960's and 1970's. Debris flows have been especially important agents of geomorphic change along Tahoma Creek, which drains South Tahoma Glacier. Debris flows in Tahoma Creek valley have transported downstream about 107 m3 Of sediment since 1967, causing substantial aggradation and damage to roads and facilities in Mount Rainier National Park. The average denudation rate in the upper part of the Tahoma Creek drainage basin in the same period has been extraordinarily high: more than 20 millimeters per year, a value exceeded only rarely in basins affected by debris flows. However, little or none of this sediment has yet passed out of the Tahoma Creek drainage basin. Outburst floods from South Tahoma Glacier form by release of subglacially stored water. The volume of stored water discharged during a typical outburst flood would form a layer several tens of millimeters thick over the bed of the entire glacier, though it is more likely that large linked cavities account for most of the storage. Statistical analysis shows that outburst floods usually occur during periods of atypically hot or rainy weather in summer or early autumn, and that the probability of an outburst increases with temperature (a proxy measure of ablation rate) or rainfall rate. On the basis of these results, we suggest that outburst floods are triggered when rapid input of water to the glacier bed causes transient increase in water pressure, thereby destabilizing the linked-cavity system. The probabilistic nature of

  18. Incidence of marine debris in cetaceans stranded and bycaught in Ireland: Recent findings and a review of historical knowledge.

    Science.gov (United States)

    Lusher, Amy L; Hernandez-Milian, Gema; Berrow, Simon; Rogan, Emer; O'Connor, Ian

    2018-01-01

    Interactions between marine mammals and plastic debris have been the focus of studies for many years. Examples of interactions include entanglement in discarded fishing items or the presence of ingested debris in digestive tracts. Plastics, including microplastics, are a form of marine debris globally distributed in coastal areas, oceanic waters and deep seas. Cetaceans which strand along the coast present a unique opportunity to study interactions between animals with macro- and microplastics. A combination of novel techniques and a review of historical data was used to complete an extensive study of cetaceans interacting with marine debris within Irish waters. Of the 25 species of marine mammals reported in Irish waters, at least 19 species were reported stranded between 1990 and 2015 (n = 2934). Two hundred and forty-one of the stranded cetaceans presented signs of possible entanglement or interactions with fisheries. Of this number, 52.7% were positively identified as bycatch or as entangled in fisheries items, 26.6% were classified as mutilated and 20.7% could not be related to fisheries but showed signs of entanglement. In addition, 274 cetaceans were recorded as by-catch during observer programmes targeting albacore tuna. Post-mortem examinations were carried out on a total of 528 stranded and bycaught individuals and 45 (8.5%) had marine debris in their digestive tracts: 21 contained macrodebris, 21 contained microdebris and three had both macro- and microdebris. Forty percent of the ingested debris were fisheries related items. All 21 individuals investigated with the novel method for microplastics contained microplastics, composed of fibres (83.6%) and fragments (16.4%). Deep diving species presented more incidences of macrodebris ingestion but it was not possible to investigate this relationship to ecological habitat. More research on the plastic implications to higher trophic level organisms is required to understand the effects of these pollutants

  19. A Comparison of the SOCIT and DebriSat Experiments

    Science.gov (United States)

    Ausay, Erick; Blake, Brandon; Boyle, Colleen; Cornejo, Alex; Horn, Alexa; Palma, Kirsten; Pistella, Frank; Sato, Taishi; Todd, Naromi; Zimmerman, Jeffrey; hide

    2017-01-01

    This paper explores the differences between, and shares the lessons learned from, two hypervelocity impact experiments critical to the update of orbital debris environment models. The procedures and processes of the fourth Satellite Orbital Debris Characterization Impact Test (SOCIT) were analyzed and related to the ongoing DebriSat experiment. SOCIT was the first hypervelocity impact test designed specifically for satellites in Low Earth Orbit (LEO). It targeted a 1960's U.S. Navy satellite, from which data was obtained to update pre-existing NASA and DOD breakup models. DebriSat is a comprehensive update to these satellite breakup models- necessary since the material composition and design of satellites have evolved from the time of SOCIT. Specifically, DebriSat utilized carbon fiber, a composite not commonly used in satellites during the construction of the US Navy Transit satellite used in SOCIT. Although DebriSat is an ongoing activity, multiple points of difference are drawn between the two projects. Significantly, the hypervelocity tests were conducted with two distinct satellite models and test configurations, including projectile and chamber layout. While both hypervelocity tests utilized soft catch systems to minimize fragment damage to its post-impact shape, SOCIT only covered 65% of the projected area surrounding the satellite, whereas, DebriSat was completely surrounded cross-range and downrange by the foam panels to more completely collect fragments. Furthermore, utilizing lessons learned from SOCIT, DebriSat's post-impact processing varies in methodology (i.e., fragment collection, measurement, and characterization). For example, fragment sizes were manually determined during the SOCIT experiment, while DebriSat utilizes automated imaging systems for measuring fragments, maximizing repeatability while minimizing the potential for human error. In addition to exploring these variations in methodologies and processes, this paper also presents the

  20. Hydrogen sulfide generation in simulated construction and demolition debris landfills: impact of waste composition.

    Science.gov (United States)

    Yang, Kenton; Xu, Qiyong; Townsend, Timothy G; Chadik, Paul; Bitton, Gabriel; Booth, Matthew

    2006-08-01

    Hydrogen sulfide (H2S) generation in construction and demolition (C&D) debris landfills has been associated with the biodegradation of gypsum drywall. Laboratory research was conducted to observe H2S generation when drywall was codisposed with different C&D debris constituents. Two experiments were conducted using simulated landfill columns. Experiment 1 consisted of various combinations of drywall, wood, and concrete to determine the impact of different waste constituents and combinations on H2S generation. Experiment 2 was designed to examine the effect of concrete on H2S generation and migration. The results indicate that decaying drywall, even alone, leached enough sulfate ions and organic matter for sulfate-reducing bacteria (SRB) to generate large H2S concentrations as high as 63,000 ppmv. The codisposed wastes show some effect on H2S generation. At the end of experiment 1, the wood/drywall and drywall alone columns possessed H2S concentrations > 40,000 ppmv. Conversely, H2S concentrations were debris landfills are suggested.

  1. The characterization and removal of Chernobyl debris in garden soils

    International Nuclear Information System (INIS)

    Andersson, K.G.

    1991-01-01

    Severe nuclear accidents such as the one in Chernobyl in 1986 may give unacceptably high external radiation levels, which even in the late phase may make a resettlement of an evacuated population impossible unless action is taken to decrease the exposure. As the urban land areas to be reclaimed may be very large the cost of the dose reducing countermeasure to be used may be an important factor. In the Chernobyl debris the most important radionuclides concerning the long term external radiation were found to be Cs-137, Cs-134, and Ru-106. Therefore, the aim of this work is to investigate the behaviour of these radionuclides in garden soils, and on this background to examine cost-effective methods by which a reduction of the dose from such areas to people living in urban or sub-urban environments can be achieved. The fixation of the radioactive cations in soil was investigated by means of soil profile sampling, soil texture analysis, and speciation experiments. It was found that most of the Chernobyl fallout caesium was extremely firmly fixed. Much of the ruthenium was more loosely bound, to organic material. The cost-effectiveness of some dose reducing countermeasures was examined on the background of small scale tests. Here it was found that about 95% of the activity could be removed with peelable fixatives based on PVA or lignin. (author) 1 tab., 7 ills., 25 refs

  2. NASA Orbital Debris Engineering Model ORDEM2008 (Beta Version)

    Science.gov (United States)

    Stansbery, Eugene G.; Krisko, Paula H.

    2009-01-01

    This is an interim document intended to accompany the beta-release of the ORDEM2008 model. As such it provides the user with a guide for its use, a list of its capabilities, a brief summary of model development, and appendices included to educate the user as to typical runtimes for different orbit configurations. More detailed documentation will be delivered with the final product. ORDEM2008 supersedes NASA's previous model - ORDEM2000. The availability of new sensor and in situ data, the re-analysis of older data, and the development of new analytical techniques, has enabled the construction of this more comprehensive and sophisticated model. Integrated with the software is an upgraded graphical user interface (GUI), which uses project-oriented organization and provides the user with graphical representations of numerous output data products. These range from the conventional average debris size vs. flux magnitude for chosen analysis orbits, to the more complex color-contoured two-dimensional (2-D) directional flux diagrams in terms of local spacecraft pitch and yaw.

  3. Impact of the New Optimal Rules for Arbitration of Disputers Relating to Space Debris Controversies

    Science.gov (United States)

    Force, Melissa K.

    2013-09-01

    The mechanisms and procedures for settlement of disputes arising from space debris collision damage, such as that suffered by the Russian Cosmos and US Iridium satellites in 2009, are highly political, nonbinding and unpredictable - all of which contributes to the uncertainty that increases the costs of financing and insuring those endeavors that take place in near-Earth space, especially in Low Earth Orbit. Dispute settlement mechanisms can be found in the 1967 Outer Space Treaty, which provides for consultations in cases involving potentially harmful interference with activities of States parties, and in the 1972 Liability Convention which permits but does not require States - not non-governmental entities - to pursue claims in a resolution process that is nonbinding (unless otherwise agreed.) There are soft- law mechanisms to control the growth of space debris, such as the voluntary 2008 United Nations Space Debris Mitigation Guidelines, and international law and the principles of equity and justice generally provide reparation to restore a person, State or organization to the condition which would have existed if damage had not occurred, but only if all agree to a specific tribunal or international court; even then, parties may be bound by the result only if agreed and enforcement of the award internationally remains uncertain. In all, the dispute resolution process for damage resulting from inevitable future damage from space debris collisions is highly unsatisfactory. However, the Administrative Council of the Permanent Court of Arbitration's recently adopted Optional Rules for the Arbitration of Disputes Relating to Outer Space Activities are, as of yet, untested, and this article will provide an overview of the process, explore the ways in which they fill in gaps in the previous patchwork of systems and analyze the benefits and shortcomings of the new Outer Space Optional Rules.

  4. Debris Detector Verification by Hvi-Tests

    Science.gov (United States)

    Bauer, Waldemar; Drolshagen, Gerhard; Vörsmann, Peter; Romberg, Oliver; Putzar, Robin

    Information regarding Space Debris (SD) or Micrometeoroids (MM) impacting on spacecraft (S/C) or payloads (P/L) can be obtained by using environmental models e.g. MASTER (ESA) or ORDEM (NASA). The validation of such models is performed by comparison of simulated results with measured or orbital observed data. The latter is utilised for large particles and can be obtained from ground based or space based radars or telescopes. Data regarding very small but abundant particles can also be gained by analysis of retrieved hardware (e.g. Hubble Space Telescope, Space Shuttle Windows), which are brought from orbit back to Earth. Furthermore, in-situ impact detectors are an essential source for information on small size meteoroids and space debris. These kind of detectors are placed in orbit and collect impact data regarding SD and MM, sending data near real time via telemetry. Compared to the impact data which is gained by analysis of retrieved surfaces, the detected data comprise additional information regarding exact impact time and, depending on the type of detector, on the orbit and particles composition. Nevertheless, existing detectors have limitations. Since the detection area is small, statistically meaningful number of impacts are obtained for very small particles only. Measurements of particles in the size range of hundreds of microns to mm which are potentially damaging to S/C require larger sensor areas. To make use of the advantages of in-situ impact detectors and to increase the amount of impact data an innovative impact detector concept is currently under development at DLR in Bremen. Different to all previous impact detectors the Solar Generator based Impact Detector (SOLID) is not an add-on component on the S/C. SOLID makes use of existing subsystems of the S/C and adopts them for impact detection purposes. Since the number of impacts on a target in space depends linearly on the exposed area, the S/C solar panels offer a unique opportunity to use them for

  5. Active debris removal of multiple priority targets

    Science.gov (United States)

    Braun, Vitali; Lüpken, A.; Flegel, S.; Gelhaus, J.; Möckel, M.; Kebschull, C.; Wiedemann, C.; Vörsmann, P.

    2013-05-01

    Today's space debris environment shows major concentrations of objects within distinct orbital regions for nearly all size regimes. The most critical region is found at orbital altitudes near 800 km with high declinations. Within this region many satellites are operated in so called sun-synchronous orbits (SSO). Among those, there are Earth observation, communication and weather satellites. Due to the orbital geometry in SSO, head-on encounters with relative velocities of about 15 km/s are most probable and would thus result in highly energetic collisions, which are often referred to as catastrophic collisions, leading to the complete fragmentation of the participating objects. So called feedback collisions can then be triggered by the newly generated fragments, thus leading to a further population increase in the affected orbital region. This effect is known as the Kessler syndrome.Current studies show that catastrophic collisions are not a major problem today, but will become the main process for debris generation within the SSO region in the near future, even without any further launches. In order to avoid this effect, objects with a major impact on collisional cascading have to be actively removed from the critical region after their end of life. Not having the capability to perform an end-of-life maneuver in order to transfer to a graveyard orbit or to de-orbit, many satellites and rocket bodies would have to be de-orbited within a dedicated mission. In such a mission, a service satellite would perform a de-orbit maneuver, after having docked to a specific target.In this paper, chemical and electric propulsion systems were analysed with the main focus on removing multiple targets within one single mission. The targets were chosen from a previously defined priority list in order to enhance the mission efficiency. Total mission time, ΔV and system mass were identified as key parameters to allow for an evaluation of the different concepts. It was shown that it

  6. Corporate social responsibility in marine plastic debris governance.

    Science.gov (United States)

    Landon-Lane, Micah

    2018-02-01

    This paper explores the governance characteristics of marine plastic debris, some of the factors underpinning its severity, and examines the possibility of harnessing corporate social responsibility (CSR) to manage plastic use within the contextual attitudes of a contemporary global society. It argues that international and domestic law alone are insufficient to resolve the "wicked problem" of marine plastic debris, and investigates the potential of the private sector, through the philosophy of CSR, to assist in reducing the amount and impacts of marine plastic debris. To illustrate how CSR could minimise marine plastic pollution, an industry-targeted code of conduct was developed. Applying CSR would be most effective if implemented in conjunction with facilitating governance frameworks, such as supportive governmental regulation and non-governmental partnerships. This study maintains that management policies must be inclusive of all stakeholders if they are to match the scale and severity of the marine plastic debris issue. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Spiders (Araneae of stony debris in North Bohemia

    Directory of Open Access Journals (Sweden)

    Růžička, Vlastimil

    1996-12-01

    Full Text Available The arachnofauna was studied at five stony debris sites in northern Bohemia. In Central Europe, the northern and montane species inhabiting cold places live not only on mountain tops and peat bogs but also on the lower edges of boulder debris, where air streaming through the system of inner compartments gives rise to an exceedingly cold microclimate. At such cold sites, spiders can live either on bare stones (Bathyphantes simillimus, Wubanoides uralensis, or in the rich layers of moss and lichen (Diplocentria bidentata. Kratochviliella bicapitata exhibits a diplostenoecious occurence in stony debris and on the tree bark. Latithorax faustus and Theonoe minutissima display diplostenoecious occurence in stony debris and on peat bogs. The occurence of the species Scotina celans in the Czech Republic was documented for the first time.

  8. Statistical interpretation of chemical evidence pertaining to fire debris

    NARCIS (Netherlands)

    Lopatka, M.

    2016-01-01

    Forensic examination of fire debris is a notoriously difficult analytical task due to the complexity and variability of samples encountered. The development of increasingly sophisticated analytical instrumentation facilitates greater sensitivity while drastically increasing the abundance of data

  9. Space Debris - Evaluation of risk perception and countermeasures

    Science.gov (United States)

    Belviso, L.

    The problem of Space Debris not only belongs to purely technical domain Although the main effort is to establish legal background to handle with possible accident caused by space debris as well as finding countermeasures another relevant problem is the perception of risk by both general public and space operators The main objective of this paper concerns the analysis and comparison of real and perceived risk related to space debris in order to gives useful outputs for decision makers in both public and private sector of space operators A correct evaluation of the real risk deriving from space debris will be particularly useful in the next years to correctly evaluate launch and operational phases of commercial satellites as well as possible countermeasures to avoid or limitate damages In the public sector a correct evaluation of risk will represents an extremely useful tool to handle crisis management and promote correct information on space

  10. Supraglacial Ponds Regulate Runoff From Himalayan Debris-Covered Glaciers

    Science.gov (United States)

    Irvine-Fynn, Tristram D. L.; Porter, Philip R.; Rowan, Ann V.; Quincey, Duncan J.; Gibson, Morgan J.; Bridge, Jonathan W.; Watson, C. Scott; Hubbard, Alun; Glasser, Neil F.

    2017-12-01

    Meltwater and runoff from glaciers in High Mountain Asia is a vital freshwater resource for one-fifth of the Earth's population. Between 13% and 36% of the region's glacierized areas exhibit surface debris cover and associated supraglacial ponds whose hydrological buffering roles remain unconstrained. We present a high-resolution meltwater hydrograph from the extensively debris-covered Khumbu Glacier, Nepal, spanning a 7 month period in 2014. Supraglacial ponds and accompanying debris cover modulate proglacial discharge by acting as transient and evolving reservoirs. Diurnally, the supraglacial pond system may store >23% of observed mean daily discharge, with mean recession constants ranging from 31 to 108 h. Given projections of increased debris cover and supraglacial pond extent across High Mountain Asia, we conclude that runoff regimes may become progressively buffered by the presence of supraglacial reservoirs. Incorporation of these processes is critical to improve predictions of the region's freshwater resource availability and cascading environmental effects downstream.

  11. K-Basins debris removal equipment - test plan

    International Nuclear Information System (INIS)

    Pitkoff, C.C.

    1995-01-01

    An undetermined amount of debris remains in the K-Basins which must be removed. Due to the different types of debris that will be removed, a variety of tools will be required to complete this project. This test plan gives s broad scope of the requirements that will be used for testing equipment for K-Basin debris removal. The equipment tested will be used in a radioactive environment. The equipment tested will be used to retrieve, cut, clean, and package debris from both K West and K East Basins. Testing is typically divided into six primary categories: development testing, acceptance testing, qualification testing, pre-operational testing, operational testing, and production/process testing

  12. Recent advances in modeling landslides and debris flows

    CERN Document Server

    2015-01-01

    Landslides and debris flows belong to the most dangerous natural hazards in many parts of the world. Despite intensive research, these events continue to result in human suffering, property losses, and environmental degradation every year. Better understanding of the mechanisms and processes of landslides and debris flows will help make reliable predictions, develop mitigation strategies and reduce vulnerability of infrastructure. This book presents contributions to the workshop on Recent Developments in the Analysis, Monitoring and Forecast of Landslides and Debris Flow, in Vienna, Austria, September 9, 2013. The contributions cover a broad spectrum of topics from material behavior, physical modelling over numerical simulation to applications and case studies. The workshop is a joint event of three research projects funded by the European Commission within the 7th Framework Program: MUMOLADE (Multiscale modelling of landslides and debris flows, www.mumolade.com), REVENUES (Numerical Analysis of Slopes with V...

  13. Space debris and other threats from outer space

    CERN Document Server

    Pelton, Joseph N

    2013-01-01

    The mounting problem of space debris in low earth orbit and its threat to the operation of application satellites has been increasingly recognized as space activities increase. The efforts of the Inter Agency Space Debris Coordinating Committee (IADC) and UN COPUS have now led to international guidelines to mitigate the creation of new debris. This book discusses the technical studies being developed for active removal processes and otherwise mitigating problems of space debris, particularly in low earth orbit. This book also considers threats to space systems and the Earth that comes from natural causes such as asteroids, coronal mass ejections, and radiation. After more than half a century of space applications and explorations, the time has come to consider ways to provide sustainability for long-term space activities. 

  14. Predicting sediment delivery from debris flows after wildfire

    Science.gov (United States)

    Nyman, Petter; Smith, Hugh G.; Sherwin, Christopher B.; Langhans, Christoph; Lane, Patrick N. J.; Sheridan, Gary J.

    2015-12-01

    Debris flows are an important erosion process in wildfire-prone landscapes. Predicting their frequency and magnitude can therefore be critical for quantifying risk to infrastructure, people and water resources. However, the factors contributing to the frequency and magnitude of events remain poorly understood, particularly in regions outside western USA. Against this background, the objectives of this study were to i) quantify sediment yields from post-fire debris flows in southeast Australian highlands and ii) model the effects of landscape attributes on debris flow susceptibility. Sediment yields from post-fire debris flows (113-294 t ha- 1) are 2-3 orders of magnitude higher than annual background erosion rates from undisturbed forests. Debris flow volumes ranged from 539 to 33,040 m3 with hillslope contributions of 18-62%. The distribution of erosion and deposition above the fan were related to a stream power index, which could be used to model changes in yield along the drainage network. Debris flow susceptibility was quantified with a logistic regression and an inventory of 315 debris flow fans deposited in the first year after two large wildfires (total burned area = 2919 km2). The differenced normalised burn ratio (dNBR or burn severity), local slope, radiative index of dryness (AI) and rainfall intensity (from rainfall radar) were significant predictors in a susceptibility model, which produced excellent results in terms identifying channels that were eroded by debris flows (Area Under Curve, AUC = 0.91). Burn severity was the strongest predictor in the model (AUC = 0.87 when dNBR is used as single predictor) suggesting that fire regimes are an important control on sediment delivery from these forests. The analysis showed a positive effect of AI on debris flow probability in landscapes where differences in moisture regimes due to climate are associated with large variation in soil hydraulic properties. Overall, the results from this study based in the

  15. Microfouling communities from pelagic and benthic marine plastic debris sampled across Mediterranean coastal waters

    Directory of Open Access Journals (Sweden)

    Mercedes Masó

    2016-09-01

    Full Text Available The present study used scanning electron microscopy to characterize the organisms colonizing marine plastic debris collected from pelagic and benthic habitats across Mediterranean coastal waters of Greece, Italy and Spain. A total of 42 fragments of plastic were collected during the COMSOM experimental cruise, 16 from the seafloor and 26 from surface waters. The results showed that diatoms were the most abundant organisms on both pelagic and benthic plastics. The diatom Ceratoneis closterium, frequently observed on surface plastics (73%, is a harmful microalgae associated with mucilage events in the Mediterranean. The abundance of marine plastic in coastal and oceanic waters may provide new habitats that offer an easy substrate for these invasive organisms. Furthermore, the colonization of these new environments might reduce the success of life strategies, or drive the organisms out of their essential habitat by dispersion and rafting phenomena. The results of the present work highlight the need to increase our knowledge of the consequences of colonization of plastics introduced into the marine environment, and the need to raise awareness of the potential impacts of debris accumulation on biodiversity of marine ecosystems.

  16. Scaling and design of landslide and debris-flow experiments

    Science.gov (United States)

    Iverson, Richard M.

    2015-01-01

    Scaling plays a crucial role in designing experiments aimed at understanding the behavior of landslides, debris flows, and other geomorphic phenomena involving grain-fluid mixtures. Scaling can be addressed by using dimensional analysis or – more rigorously – by normalizing differential equations that describe the evolving dynamics of the system. Both of these approaches show that, relative to full-scale natural events, miniaturized landslides and debris flows exhibit disproportionately large effects of viscous shear resistance and cohesion as well as disproportionately small effects of excess pore-fluid pressure that is generated by debris dilation or contraction. This behavioral divergence grows in proportion to H3, where H is the thickness of a moving mass. Therefore, to maximize geomorphological relevance, experiments with wet landslides and debris flows must be conducted at the largest feasible scales. Another important consideration is that, unlike stream flows, landslides and debris flows accelerate from statically balanced initial states. Thus, no characteristic macroscopic velocity exists to guide experiment scaling and design. On the other hand, macroscopic gravity-driven motion of landslides and debris flows evolves over a characteristic time scale (L/g)1/2, where g is the magnitude of gravitational acceleration and L is the characteristic length of the moving mass. Grain-scale stress generation within the mass occurs on a shorter time scale, H/(gL)1/2, which is inversely proportional to the depth-averaged material shear rate. A separation of these two time scales exists if the criterion H/L experiments can be used to study some details of landslide and debris-flow behavior but cannot be used to study macroscopic landslide or debris-flow dynamics.

  17. Development and Flight Demonstration of Space Debris Monitor (SDM)

    Science.gov (United States)

    Kitazawa, Yukihito; Hanada, Toshiya; Matsumoto, Haruhisa; Kobayashi, Masanori; Sakurai, Akira; Yasaka, Tetsuo; Funakoshi, Kunihiro; Hasegawa, Sunao; Akahoshi, Yasuhiro; Kimoto, Yugo; Okudaira, Osamu; Kamiya, Koki; Nakamura, Maki

    2016-07-01

    The space debris monitor (SDM) is a large-area impact sensor for in situ measurements of micro-meteoroids and space debris of the sub-millimeter to millimeter size in the near-Earth space environment. These meteoroid and debris particles are very small to be detected by ground-based observations (radars and optical telescopes) but are sufficiently large to cause serious damage to spacecraft equipment in the low Earth orbit region. The nominal detection area of the SDM is 0.1 m^2 (0.35 m × 0.3 m), but its dimensions can be easily modified to accommodate different SDM constraints. The SDM is made from a flexible printed circuit, which is produced from a thin film of a nonconductive material (such as polyimide) on which thin conductive stripes are formed in parallel. The stripe width is approximately 50 μm, and the spatial separation is approximately 100 μm, as shown in Figure 1. When a micro-debris particle with an effective diameter near to or larger than the spatial separation of the stripes (here approximately 100 μm) collides with the sensor film at a velocity sufficient to penetrate it, one or more of the stripes are cut and become nonconductive. Debris impacts can thus be detected by monitoring the electrical conductivity (resistivity) of the stripes. This sensor system can measure the size of the incident micro-debris particles by detecting the number of severed stripes. The measurement concept is registered as a patent in many countries. The first SDM was launched with HTV-5 on August 19, 2015 and represented the world's first micro-debris measurement demonstration experiment to be conducted on the ISS using the concept of conductive (resistive) strip lines for real-time debris detection.

  18. Environmental Assessment for Airborne Laser Debris Management Vandenberg AFB, California

    Science.gov (United States)

    2008-07-01

    only a subspecies of the green sea turtle, is confined to the eastern Pacific. The species is protected in the Galapagos Islands and is nominally... Galapagos Islands have been subjected to severe challenges by settlers and fishermen. Loggerhead Sea Turtle (Caretta caretta) The loggerhead sea...debris disposal actions, LFTS target missile debris is not anticipated to reach the shore or the Channel Islands . However, shore evaluations would be

  19. Investigation of debris bed formation, spreading and coolability

    International Nuclear Information System (INIS)

    Kudinov, P.; Konovalenko, A.; Grishchenko, D.; Yakush, S.; Basso, S.; Lubchenko, N.; Karbojian, A.

    2013-08-01

    The work is motivated by the severe accident management strategy adopted in Nordic type BWRs. It is assumed that core melt ejected from the vessel will fragment, quench and form a coolable debris bed in a deep water pool below the vessel. In this work we consider phenomena relevant to the debris bed formation and coolability. Several DEFOR-A (Debris Bed Formation - Agglomeration) tests have been carried out with new corium melt material and a melt releasing nozzle mockup. The influence of the melt material, melt superheat, jet free fall height on the (i) faction of agglomerated debris, (ii) particle size distribution, (iii) ablation/plugging of the nozzle mockup has been addressed. Results of the DECOSIM (Debris Coolability Simulator) code validation against available COOLOCE data are presented in the report. The dependence of DHF on system pressure from COOLOCE experiments can be reproduced quite accurately if either the effective particle diameter or debris bed porosity is increased. For a cylindrical debris bed, good agreement is achieved in DECOSIM simulations for the particle diameter 0.89 mm and porosity 0.4. The results obtained are consistent with MEWA simulation where larger particle diameters and porosities were found to be necessary to reproduce the experimental data on DHF. It is instructive to note that results of DHF prediction are in better agreement with POMECO-HT data obtained for the same particles. It is concluded that further clarification of the discrepancies between different experiments and model predictions. In total 13 exploratory tests were carried out in PDS (particulate debris spreading) facility to clarify potential influence of the COOLOCE (VTT) facility heaters and TCs on particle self-leveling process. Results of the preliminary analysis suggest that there is no significant influence of the pins on self-leveling, at least for the air superficial velocities ranging from 0.17 up to 0.52 m/s. Further confirmatory tests might be needed

  20. Investigation of debris bed formation, spreading and coolability

    Energy Technology Data Exchange (ETDEWEB)

    Kudinov, P.; Konovalenko, A.; Grishchenko, D.; Yakush, S.; Basso, S.; Lubchenko, N.; Karbojian, A. [Royal Institute of Technology, KTH. Div. of Nuclear Power Safety, Stockholm (Sweden)

    2013-08-15

    The work is motivated by the severe accident management strategy adopted in Nordic type BWRs. It is assumed that core melt ejected from the vessel will fragment, quench and form a coolable debris bed in a deep water pool below the vessel. In this work we consider phenomena relevant to the debris bed formation and coolability. Several DEFOR-A (Debris Bed Formation - Agglomeration) tests have been carried out with new corium melt material and a melt releasing nozzle mockup. The influence of the melt material, melt superheat, jet free fall height on the (i) faction of agglomerated debris, (ii) particle size distribution, (iii) ablation/plugging of the nozzle mockup has been addressed. Results of the DECOSIM (Debris Coolability Simulator) code validation against available COOLOCE data are presented in the report. The dependence of DHF on system pressure from COOLOCE experiments can be reproduced quite accurately if either the effective particle diameter or debris bed porosity is increased. For a cylindrical debris bed, good agreement is achieved in DECOSIM simulations for the particle diameter 0.89 mm and porosity 0.4. The results obtained are consistent with MEWA simulation where larger particle diameters and porosities were found to be necessary to reproduce the experimental data on DHF. It is instructive to note that results of DHF prediction are in better agreement with POMECO-HT data obtained for the same particles. It is concluded that further clarification of the discrepancies between different experiments and model predictions. In total 13 exploratory tests were carried out in PDS (particulate debris spreading) facility to clarify potential influence of the COOLOCE (VTT) facility heaters and TCs on particle self-leveling process. Results of the preliminary analysis suggest that there is no significant influence of the pins on self-leveling, at least for the air superficial velocities ranging from 0.17 up to 0.52 m/s. Further confirmatory tests might be needed

  1. Orbital Debris: Technical and Legal Issues and Solutions

    Science.gov (United States)

    2006-08-01

    legal, political, and economic consequences of orbital debris are described. The current technical and legal controls on the creation of debris...well as quantification of the level of risk posed by it. Part III catalogs some of the many technical, legal, political, and economic consequences...magnetic field and concentrate in two doughnut -shaped (torus) areas around the equator; these regions are called the Van Allen radiation belts.20 The

  2. Observations on Marine Debris at Coastal Areas of Takalar District and Makassar City South Sulawesi

    OpenAIRE

    Tahir, Akbar; Werorilangi, Shinta; Zulkarnaen, Adi; Isman, Fajar Mulana; Faisal, Ahmad

    2017-01-01

    Marine debris is defined as material that is solid, persistent, manufactured or processed, and deliberately or not-deliberately left in the marine environment. Marine debris comes in many shapes and forms, ranging in size from microscopic microplastics to large vessels. Marine debris is a big and growing global problem, pose threats to marine life sustainability. Plastic is a major component of marine debris, and single use packaging accounts for an increasing part of the global marine debris...

  3. Mapping coastal marine debris using aerial imagery and spatial analysis.

    Science.gov (United States)

    Moy, Kirsten; Neilson, Brian; Chung, Anne; Meadows, Amber; Castrence, Miguel; Ambagis, Stephen; Davidson, Kristine

    2017-12-19

    This study is the first to systematically quantify, categorize, and map marine macro-debris across the main Hawaiian Islands (MHI), including remote areas (e.g., Niihau, Kahoolawe, and northern Molokai). Aerial surveys were conducted over each island to collect high resolution photos, which were processed into orthorectified imagery and visually analyzed in GIS. The technique provided precise measurements of the quantity, location, type, and size of macro-debris (>0.05m 2 ), identifying 20,658 total debris items. Northeastern (windward) shorelines had the highest density of debris. Plastics, including nets, lines, buoys, floats, and foam, comprised 83% of the total count. In addition, the study located six vessels from the 2011 Tōhoku tsunami. These results created a baseline of the location, distribution, and composition of marine macro-debris across the MHI. Resource managers and communities may target high priority areas, particularly along remote coastlines where macro-debris counts were largely undocumented. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Spatial patterns of plastic debris along Estuarine shorelines.

    Science.gov (United States)

    Browne, Mark A; Galloway, Tamara S; Thompson, Richard C

    2010-05-01

    The human population generates vast quantities of waste material. Macro (>1 mm) and microscopic (plastic debris represent a substantial contamination problem. Here, we test hypotheses about the influence of wind and depositional regime on spatial patterns of micro- and macro-plastic debris within the Tamar Estuary, UK. Debris was identified to the type of polymer using Fourier-transform infrared spectroscopy (FT-IR) and categorized according to density. In terms of abundance, microplastic accounted for 65% of debris recorded and mainly comprised polyvinylchloride, polyester, and polyamide. Generally, there were greater quantities of plastic at downwind sites. For macroplastic, there were clear patterns of distribution for less dense items, while for microplastic debris, clear patterns were for denser material. Small particles of sediment and plastic are both likely to settle slowly from the water-column and are likely to be transported by the flow of water and be deposited in areas where the movements of water are slower. There was, however, no relationship between the abundance of microplastic and the proportion of clay in sediments from the strandline. These results illustrate how FT-IR spectroscopy can be used to identify the different types of plastic and in this case was used to indicate spatial patterns, demonstrating habitats that are downwind acting as potential sinks for the accumulation of debris.

  5. Space debris removal system using a small satellite

    Science.gov (United States)

    Nishida, Shin-Ichiro; Kawamoto, Satomi; Okawa, Yasushi; Terui, Fuyuto; Kitamura, Shoji

    2009-07-01

    Since the number of satellites in Earth orbit is steadily increasing, space debris will eventually pose a serious problem to near-Earth space activities if left unchecked, and so effective measures to mitigate it are becoming urgent. Equipping new satellites with an end-of-life de-orbit or orbital lifetime reduction capability could be an effective means of reducing the amount of debris by reducing the probability of the collisions between objects. On the other hand, the active removal of space debris and the retrieval of failed satellites by spacecraft are other possible measures. The Institute of Aerospace Technology, Japan Aerospace Exploration Agency (JAXA), is studying a micro-satellite system for active space debris removal, and is examining the applicability of electro-dynamic tether (EDT) technology as its high efficiency orbital transfer system. A small EDT package provides a possible means for lowering the orbits of objects without the need for propellant. Capture is indispensable for the retrieval of large space debris objects, and we propose a flexible robot arm for this purpose. This paper discusses a space debris removal satellite system and describes the development status of prototypes of the EDT package and a new robot arm for capturing non-cooperative targets.

  6. Plastic debris retention and exportation by a mangrove forest patch

    International Nuclear Information System (INIS)

    Ivar do Sul, Juliana A.; Costa, Monica F.; Silva-Cavalcanti, Jacqueline S.; Araújo, Maria Christina B.

    2014-01-01

    Highlights: • Estuaries and mangrove forests are rarely studied for marine plastic debris loads. • Types of plastic items and mangrove forest habitats determine the potential of debris retention. • Mangrove habitats are temporary sinks of plastic debris from river and marine origins. • Plastics rapidly accumulate in mangrove forest, but are exported slowly. • Fauna and fishers using mangrove forest habitats are at risk of interaction with plastic debris. -- Abstract: An experiment observed the behavior of selected tagged plastic items deliberately released in different habitats of a tropical mangrove forest in NE Brazil in late rainy (September) and late dry (March) seasons. Significant differences were not reported among seasons. However, marine debris retention varied among habitats, according to characteristics such as hydrodynamic (i.e., flow rates and volume transported) and relative vegetation (Rhizophora mangle) height and density. The highest grounds retained significantly more items when compared to the borders of the river and the tidal creek. Among the used tagged items, PET bottles were more observed and margarine tubs were less observed, being easily transported to adjacent habitats. Plastic bags were the items most retained near the releasing site. The balance between items retained and items lost was positive, demonstrating that mangrove forests tend to retain plastic marine debris for long periods (months-years)

  7. Analysis of River Blocking Induced by a Debris Flow

    Directory of Open Access Journals (Sweden)

    Lijuan Wang

    2017-01-01

    Full Text Available Both the Wenchuan earthquake on May 12, 2008, and the Lushan earthquake on April 12, 2013, produced many coseismic landslides along the Nanya River in Shimian City. Subsequent debris flows that initiated from these landslides and are triggered by intense rainfall become the secondary hazard in the years after the earthquake; in particular, some debris flows led to a serious river blocking event. For example, the Guangyuanbao debris flow which occurred on July 04, 2013, partly blocked the Nanya River, presenting a major threat to the national highway and residential areas. To analyze the pattern of landslide damming, we analyzed numerical simulations of the movement characteristics of the Guangyuanbao debris flow using rainfall intensities with varying recurrence periods of 5, 20, and 50 years. The accuracy of the spreading of the numerical simulation is about 90%. The simulation indicated a small volume of sediment entering the river for a rainfall under 5-year return period. A debris flow induced by rainfall under 20-year return period partly blocked the river, while rainfall under 50-year return period has potential to block the river completely. This proposed analysis of river blocking induced by a debris flow could be used for disaster prevention in earthquake-stricken area.

  8. Experimental study of self-leveling behavior in debris bed

    International Nuclear Information System (INIS)

    Zhang, Bin; Harada, Tetsushi; Hirahara, Daisuke; Matsumoto, Tatsuya; Morita, Koji; Fukuda, Kenji; Yamano, Hidemasa; Suzuki, Tohru; Tobita, Yoshiharu

    2008-01-01

    After a core disruptive accident in a sodium-cooled fast reactor, core debris may settle on locations such as within the core-support structure or in the lower inlet plenum of the reactor vessel as debris beds, as a consequence of rapid quenching and fragmentation of core materials in subcooled sodium. The particle beds that are initially of varying depth have been observed to undergo a process of self-leveling when sodium boiling occurs within the beds. The boiling is believed to provide the driven force with debris needed to overcome resisting forces. Self-leveling ability has much effect on heat-removal capability of debris beds. In the present study, characteristics of self-leveling behaviors were investigated experimentally with simulant materials. Although the decay heat from fuel debris drives the coolant boiling in reactor accident conditions, the present experiments employed depressurization boiling of water to simulate axially increasing void distribution in a debris bed, which consists of solid particles of alumina or lead with different density. The particle size (from 0.5 mm to 6 mm in diameter) and shape (spherical or non-spherical particles) were also taken as experimental parameters. A rough criteria for self-leveling occurrence is proposed and compared with the experimental results. Characteristics of the self-leveling behaviors observed are analyzed and extrapolate to reactor accident conditions. (author)

  9. A Comparison of the SOCIT and DebriSat Experiments

    Science.gov (United States)

    Ausay, E.; Cornejo, A.; Horn, A.; Palma, K.; Sato, T.; Blake, B.; Pistella, F.; Boyle, C.; Todd, N.; Zimmerman, J.; hide

    2017-01-01

    This paper explores the differences between, and shares the lessons learned from, two hypervelocity impact experiments critical to the update of Department of Defense (DOD) and National Aeronautics and Space Administration (NASA) satellite breakup models. The procedures as well as the processes of the fourth Satellite Orbital Debris Characterization Impact Test (SOCIT4) were analyzed and related to the ongoing DebriSat experiment. SOCIT4 accounted for about 90% of the entire satellite mass, but only analyzed approximately 59% with a total of approximately 4,700 fragments. DebriSat aims to recover and analyze 90% of the initial mass and to do so, fragments with at least a longest dimension of 2 mm are collected and processed. DebriSat's use of modern materials, especially carbon fiber, significantly increases the fragment count and to date, there are over 126,000 fragments collected. Challenges, such as procedures and human inputs, encountered throughout the DebriSat experiment are also shared. While, SOCIT4 laid the foundation for the majority of DebriSat processes, the technological advancements since SOCIT4 allow for more accurate, rigorous, and in-depth, procedures that will aid the update of satellite breakup models.

  10. Economic analysis requirements in support of orbital debris regulatory policy

    Science.gov (United States)

    Greenberg, Joel S.

    1996-10-01

    As the number of Earth orbiting objects increases so does the potential for generating orbital debris with the consequent increase in the likelihood of impacting and damaging operating satellites. Various debris remediation approaches are being considered that encompass both in-orbit and return-to-Earth schema and have varying degrees of operations, cost, international competitiveness, and safety implications. Because of the diversity of issues, concerns and long-term impacts, there is a clear need for the setting of government policies that will lead to an orderly abatement of the potential orbital debris hazards. These policies may require the establishment of a supportive regulatory regime. The Department of Transportation is likely to have regulatory responsibilities relating to orbital debris stemming from its charge to protect the public health and safety, safety of property, and national security interests and foreign policy interests of the United States. This paper describes DOT's potential regulatory role relating to orbital debris remediation, the myriad of issues concerning the need for establishing government policies relating to orbital debris remediation and their regulatory implications, the proposed technological solutions and their economic and safety implications. Particular emphasis is placed upon addressing cost-effectiveness and economic analyses as they relate to economic impact analysis in support of regulatory impact analysis.

  11. Using experiential marine debris education to make an impact: Collecting debris, informing policy makers, and influencing students.

    Science.gov (United States)

    Owens, Katharine A

    2018-02-01

    The Shore to Statehouse project supported the creation of an open-source, replicable, undergraduate experiential course on marine debris. Funded by the National Oceanic and Atmospheric Administration, the course allowed undergraduate students in Connecticut, USA, to collect marine debris locally, then create a policy report for state legislators. Here we share the results of the project including data on four accumulation surveys on the Long Island Sound, as well as the impact on student motivation, attitudes, and behavior levels. Results include finding over 1600 individual pieces of debris totaling 19.4kg (42.8lb). In addition, the students experienced statistically significant improvements in knowledge and behavior scores. This open-source course can be replicated, empowering students to remove debris, provide important information to local policy makers, and improve knowledge and behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Global Analysis of Anthropogenic Debris Ingestion by Sea Turtles

    Science.gov (United States)

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

    2014-01-01

    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. Análisis Global de la Ingesta de Residuos Antropogénicos por Tortugas Marinas La ingesta de residuos marinos puede tener efectos letales y subletales sobre las tortugas marinas y otros animales. Aunque hay investigadores que han reportado la ingesta de residuos antropogénicos por tortugas marinas y la incidencia de la ingesta de residuos ha incrementado con el tiempo, no ha habido una síntesis global del fenómeno desde 1985. Por esto analizamos 37 estudios publicados, desde

  13. Effects of Fireplace Use on Forest Vegetation and Amount of Woody Debris in Suburban Forests in Northwestern Switzerland

    Science.gov (United States)

    Hegetschweiler, K. Tessa; van Loon, Nicole; Ryser, Annette; Rusterholz, Hans-Peter; Baur, Bruno

    2009-02-01

    Urban forests are popular recreation areas in Europe. Several of these temperate broad-leaved forests also have a high conservation value due to sustainable management over many centuries. Recreational activities, particularly the use of fireplaces, can cause extensive damage to soil, ground vegetation, shrubs, and trees. Firewood collection depletes woody debris, leading to a loss of habitat for specialized organisms. We examined the effects of fireplace use on forest vegetation and the amount of woody debris by comparing disturbed and control plots in suburban forests in northwestern Switzerland. At frequently used fireplaces, we found reduced species densities in the ground vegetation and shrub layer and changes in plant species composition due to human trampling within an area of 150-200 m2. Picnicking and grilling also reduced the height and changed the age structure of shrubs and young trees. The amount of woody debris was lower in disturbed plots than in control plots. Pieces of wood with a diameter of 0.6-7.6 cm were preferentially collected by fireplace users. The reduction in woody debris volume extended up to a distance of 16 m from the fire ring, covering an area of 800 m2 at each picnic site. In order to preserve the ecological integrity of urban forests and to maintain their attractiveness as important recreation areas, we suggest depositing logging residues to be used as firewood and to restrict visitor movements near picnic sites.

  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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Performance testing of the new AMPAC fire debris bag against three other commercial fire debris bags.

    Science.gov (United States)

    Grutters, Michiel M P; Dogger, Judith; Hendrikse, Jeanet N

    2012-09-01

    Fire debris evidence is collected and stored in a wide range of containers, including various polymer bags. Four different polymer bags have been investigated, including the NYLON, DUO, ALU, and AMPAC bags. The latter is the successor of the Kapak Fire DebrisPAK™. Microscopy and infrared spectroscopy were used to elucidate the composition of the bags. Gas chromatography/mass spectrometry was used to investigate performance parameters such as background volatiles, leak rate, cross-contamination, recovery, and sorption. The NYLON bag was susceptible for leakage and cross-contamination and showed decreased recoveries. The DUO and ALU bags showed some background volatiles, sorption, and poor recoveries. The AMPAC bag performed excellent: low background, no leakage or cross-contamination, good recoveries, and only traces of sorption. Heat sealing proved to be the best method of closure. Preliminary studies on AMPAC bags showed that polyethylene clamps are easy to use on-site and preserve ignitable liquids adequately for a limited period of time. © 2012 American Academy of Forensic Sciences.

  16. Occurrence of giant planets around stars with dusty debris disks

    Science.gov (United States)

    Meshkat, Tiffany; Mawet, Dimitri; Bryan, Marta; Hinkley, Sasha; Bowler, Brendan; Stapelfeldt, Karl; Batygin, Konstantin; Padgett, Deborah; Morales, Farisa; serabyn, Eugene; Christiaens, Valentin; Brandt, Timothy; Wahhaj, Zahed

    2018-01-01

    Debris disks may be the signposts of recent planet formation. The dust, which is generated in collisional cascades of asteroids and comets, is enhanced by the gravitational stirring of gas giant planets. Thus bright debris disk systems are natural targets for imaging searches for planets, as it indicates that the host star likely possesses some kind of planetary system. In this work, we describe a joint high contrast imaging survey for planetary mass companions at Keck and VLT of the last significant sample of debris disks identified by the Spitzer Space Telescope. No new substellar companions were discovered in our survey of Spitzer-selected targets. We combine these observations with from three published surveys, to put constraints on the frequency of planets around debris disk stars in the largest sample to date. We also obtained published data on stars that do not show infrared excesses for a control sample. We assume a double power law distribution of the form f(m,a) = Cm^alpha a^beta for this population of companions. We find that the frequency of giant planets with masses 5-20 MJup and separations 10-1000 au around stars with debris disks is 6.3% (68% confidence interval 3.7-9.8%), compared to 0.7% (68% confidence interval 0.2-1.8%) for the control sample of stars without disks. For the first time, we show that the occurrence of young giant planets around stars with debris disks is higher than those without debris disks at the 88% confidence level, tentatively suggesting that these distributions are distinct.

  17. Geophysical features influence the accumulation of beach debris on Caribbean islands.

    Science.gov (United States)

    Schmuck, Alexandra M; Lavers, Jennifer L; Stuckenbrock, Silke; Sharp, Paul B; Bond, Alexander L

    2017-08-15

    Anthropogenic beach debris was recorded during beach surveys of 24 Caribbean islands during April 2014-April 2016. Beach debris was classified according to material type (e.g., polystyrene) and item use (e.g., fishing). Geophysical features (substrate type, beach direction, and human accessibility) of sample sites were recorded in order to investigate their relationship with debris density. Results suggest the density of macro debris (items >5mm) is highest on uninhabited, sandy beaches facing a leeward direction. Higher debris quantities on inaccessible beaches may be due to less frequent beach clean ups. Frequently accessed beaches exhibited lower macro, but higher micro debris (items 1-5mm) densities, possibly due to removal of macro debris during frequent beach clean ups. This suggests that while geophysical features have some influence on anthropogenic debris densities, high debris densities are occurring on all islands within the Caribbean region regardless of substrate, beach direction, or human accessibility. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Space-based detection of space debris by photometric and polarimetric characteristics

    Science.gov (United States)

    Pang, Shuxia; Wang, Hu; Lu, Xiaoyun; Shen, Yang; Pan, Yue

    2017-10-01

    The number of space debris has been increasing dramatically in the last few years, and is expected to increase as much in the future. As the orbital debris population grows, the risk of collision between debris and other orbital objects also grows. Therefore, space debris detection is a particularly important task for space environment security, and then supports for space debris modeling, protection and mitigation. This paper aims to review space debris detection systematically and completely. Firstly, the research status of space debris detection at home and abroad is presented. Then, three kinds of optical observation methods of space debris are summarized. Finally, we propose a space-based detection scheme for space debris by photometric and polarimetric characteristics.

  19. Ionic debris measurement of three extreme ultraviolet sources

    Science.gov (United States)

    Sporre, J.; Castaño, C. H.; Raju, R.; Ruzic, D. N.

    2009-08-01

    Generation of debris in extreme ultraviolet (EUV) light sources is an inherent and real threat to the lifetime of collection optics. Debris measurement of these sources is useful to enable source suppliers to estimate collector lifetime. At the Center for Plasma Material Interactions (CPMI) at the University of Illinois, an Illinois calibrated spherical sector electrostatic energy analyzer (ICE) was built to measure the ion debris flux in absolute units. In addition to ion flux, the detector is also capable of identifying different ion species present in the plasma utilizing energy-to-charge ratio discrimination. The lifetime of the collector optics is calculated using the measured ion flux. In the current investigation we compare the measurement of ion debris production in three different EUV sources: the Energetiq EQ-10M, the AIXUV-100, and the XTREME XTS 13-35. In the EQ-10M source, three angular measurements are coupled with three variations in operating pressure to measure consequent effects on debris production. These measurements reveal four predominant ion species in the energetic debris analysis: C+, Si+, Xe+, and Xe2+. The amount of debris is reduced as pressure is increased. Various debris mitigation methods are implemented in the AIXUV-100 source and results reveal that four ion species are observed (Ar+, Xe+, Xe2+, and W+), though there does not seem to be a dominant species. The first mitigation technique, backstreaming argon toward the source, reduces the amount of Ar+, Xe2+, and W+, yet increases the amount of Xe+ The increase in Xe+ flux is explained based on charge exchange phenomena. The ICE machine was then attached 1.92 m away from the pinch of XTS 13-35 source, and placed at 25° away from the normal line. The comparison of results reveals that the XTS 13-35 and the EQ-10M sources produced comparable amounts of energetic ion flux per watt of EUV light produced. The AIXUV-100 source generated more ion debris flux per watt of EUV light than the

  20. Forensic analyses of explosion debris from the January 2, 1992 Pd/D2O electrochemistry incident at SRI International

    International Nuclear Information System (INIS)

    Andresen, B.; Whipple, R.; Vandervoort, D.; Grant, P.

    1992-01-01

    The January 2, 1992 explosion in an electrochemistry laboratory at SRI International (SRI) resulted in the death of scientist Andrew Riley, and gained some notoriety due to its association with experimental work in the controversial field of cold fusion research. Selected components of explosion debris were subjected to forensic analyses at LLNL to elucidate potential causes of, or contributing factors to, the explosion. Interrogation of the debris by LLNL encompassed nuclear, chemical, physical, and materials investigations. Nuclear studies for the determination of tritium and neutron-activation products in stainless steel and brass were negative. No evidence of signature species indicative of orthodox nuclear events was detected. The inorganic and particulate analyses were likewise negative with respect to residues of unexpected chemical species. Such target compounds included conventional explosives, accelerants, propellants, or any exceptional industrial chemicals. The GC-MS analyses of trace organic components in the explosion debris provided perhaps the most interesting results obtained at LLNL. Although no evidence of organic explosives, oxidizers, or other unusual compounds was detected, the presence of a hydrocarbon oil in the interior of the electrochemical cell was established. It is likely that its source was lubricating fluid from the machining of the metal cell components. If residues of organic oils are present during electrolysis experiments, the potential exists for an explosive reaction in the increasingly enriched oxygen atmosphere within the headspace of a metal cell

  1. Estimating Foreign-Object-Debris Density from Photogrammetry Data

    Science.gov (United States)

    Long, Jason; Metzger, Philip; Lane, John

    2013-01-01

    Within the first few seconds after launch of STS-124, debris traveling vertically near the vehicle was captured on two 16-mm film cameras surrounding the launch pad. One particular piece of debris caught the attention of engineers investigating the release of the flame trench fire bricks. The question to be answered was if the debris was a fire brick, and if it represented the first bricks that were ejected from the flame trench wall, or was the object one of the pieces of debris normally ejected from the vehicle during launch. If it was typical launch debris, such as SRB throat plug foam, why was it traveling vertically and parallel to the vehicle during launch, instead of following its normal trajectory, flying horizontally toward the north perimeter fence? By utilizing the Runge-Kutta integration method for velocity and the Verlet integration method for position, a method that suppresses trajectory computational instabilities due to noisy position data was obtained. This combination of integration methods provides a means to extract the best estimate of drag force and drag coefficient under the non-ideal conditions of limited position data. This integration strategy leads immediately to the best possible estimate of object density, within the constraints of unknown particle shape. These types of calculations do not exist in readily available off-the-shelf simulation software, especially where photogrammetry data is needed as an input.

  2. An example of debris-flows hazard modeling using GIS

    Directory of Open Access Journals (Sweden)

    L. Melelli

    2004-01-01

    Full Text Available We present a GIS-based model for predicting debris-flows occurrence. The availability of two different digital datasets and the use of a Digital Elevation Model (at a given scale have greatly enhanced our ability to quantify and to analyse the topography in relation to debris-flows. In particular, analysing the relationship between debris-flows and the various causative factors provides new understanding of the mechanisms. We studied the contact zone between the calcareous basement and the fluvial-lacustrine infill adjacent northern area of the Terni basin (Umbria, Italy, and identified eleven basins and corresponding alluvial fans. We suggest that accumulations of colluvium in topographic hollows, whatever the sources might be, should be considered potential debris-flow source areas. In order to develop a susceptibility map for the entire area, an index was calculated from the number of initiation locations in each causative factor unit divided by the areal extent of that unit within the study area. This index identifies those units that produce the most debris-flows in each Representative Elementary Area (REA. Finally, the results are presented with the advantages and the disadvantages of the approach, and the need for further research.

  3. Spectral target detection for detecting and characterizing floating marine debris

    Science.gov (United States)

    Harris, T.; Streett, D.; Belge, J.; Hulslander, D.; Ramirez, E.; Jankot, J.; Vogt, J.; Kamphaus, B.

    2012-12-01

    On March 11, 2011, a devastating 9.0 earthquake and tsunami struck Japan, claiming nearly 16,000 lives and injuring 6,000. In the following weeks large amounts of debris comprised of man-made structures and vegetation could be seen off the east coast of Japan using multiple satellite sensors. NOAA Marine Debris Program expects a portion of this debris to reach U.S. and Canadian shores over the next several years. NOAA Satellite Analysis Branch and Exelis Visual Information Solutions have led efforts to identify and assess the spatial distribution of floating marine debris across the Pacific Ocean and near the west coast of the United States. This work will provide information to groups that are aiming to mitigate possible impacts to natural resources and coastal communities. An advanced methodology is being developed and applied for remote sensing target detection of debris using spectral properties of high resolution multispectral imagery from the WorldView-2 satellite. Preliminary results are presented .

  4. Sensitivity Analysis of Launch Vehicle Debris Risk Model

    Science.gov (United States)

    Gee, Ken; Lawrence, Scott L.

    2010-01-01

    As part of an analysis of the loss of crew risk associated with an ascent abort system for a manned launch vehicle, a model was developed to predict the impact risk of the debris resulting from an explosion of the launch vehicle on the crew module. The model consisted of a debris catalog describing the number, size and imparted velocity of each piece of debris, a method to compute the trajectories of the debris and a method to calculate the impact risk given the abort trajectory of the crew module. The model provided a point estimate of the strike probability as a function of the debris catalog, the time of abort and the delay time between the abort and destruction of the launch vehicle. A study was conducted to determine the sensitivity of the strike probability to the various model input parameters and to develop a response surface model for use in the sensitivity analysis of the overall ascent abort risk model. The results of the sensitivity analysis and the response surface model are presented in this paper.

  5. Export of Plastic Debris by Rivers into the Sea.

    Science.gov (United States)

    Schmidt, Christian; Krauth, Tobias; Wagner, Stephan

    2017-11-07

    A substantial fraction of marine plastic debris originates from land-based sources and rivers potentially act as a major transport pathway for all sizes of plastic debris. We analyzed a global compilation of data on plastic debris in the water column across a wide range of river sizes. Plastic debris loads, both microplastic (particles 5 mm) are positively related to the mismanaged plastic waste (MMPW) generated in the river catchments. This relationship is nonlinear where large rivers with  population-rich catchments delivering a disproportionately higher fraction of MMPW into the sea. The 10 top-ranked rivers transport 88-95% of the global load into the sea. Using MMPW as a predictor we calculate the global plastic debris inputs form rivers into the sea to range between 0.41 and 4 × 10 6 t/y. Due to the limited amount of data high uncertainties were expected and ultimately confirmed. The empirical analysis to quantify plastic loads in rivers can be extended easily by additional potential predictors other than MMPW, for example, hydrological conditions.

  6. Apparent rotation properties of space debris extracted from photometric measurements

    Science.gov (United States)

    Šilha, Jiří; Pittet, Jean-Noël; Hamara, Michal; Schildknecht, Thomas

    2018-02-01

    Knowledge about the rotation properties of space debris objects is essential for the active debris removal missions, accurate re-entry predictions and to investigate the long-term effects of the space environment on the attitude motion change. Different orbital regions and object's physical properties lead to different attitude states and their change over time. Since 2007 the Astronomical Institute of the University of Bern (AIUB) performs photometric measurements of space debris objects. To June 2016 almost 2000 light curves of more than 400 individual objects have been acquired and processed. These objects are situated in all orbital regions, from low Earth orbit (LEO), via global navigation systems orbits and high eccentricity orbit (HEO), to geosynchronous Earth orbit (GEO). All types of objects were observed including the non-functional spacecraft, rocket bodies, fragmentation debris and uncorrelated objects discovered during dedicated surveys. For data acquisition, we used the 1-meter Zimmerwald Laser and Astrometry Telescope (ZIMLAT) at the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald, Switzerland. We applied our own method of phase-diagram reconstruction to extract the apparent rotation period from the light curve. Presented is the AIUB's light curve database and the obtained rotation properties of space debris as a function of object type and orbit.

  7. MIPS Observations of the Fabulous Four Debris Disks

    Science.gov (United States)

    Su, K. Y. L.; Stansberry, J. A.; Rieke, G. H.; Trilling, D. E.; Stapelfeldt, K. R.; Werner, M. W.; Beichman, C.; Chen, C.; Marengo, M.; Megeath, T.; Backman, D.; van Cleve, J.

    2004-12-01

    The Multiband Imaging Photometer for Spitzer (MIPS) provides long-wavelength capability with imaging bands at 24, 70, and 160 um. We will present the MIPS images of the Fabulous Four Debris Disks: Beta Pictoris (A5 V), Epsilon Eridani (K2 V), Fomalhaut (A3 V) and Vega (A0 V). These systems discovered by IRAS possess large far-infrared excess emission above photosphere, indicating the existence of a circumstellar dusty disk. Given the main-sequence ages of these stars ( ˜12 Myr for Beta Pictoris, ˜730 Myr for Epsilon Eridani, ˜200 Myr for Fomalhaut, and ˜350 Myr for Vega), the dust in the systems could not be primordial as it would have been removed by radiation pressure and Poynting-Robertson drag on relatively short time scales ( ˜1E4 yr). The second-generation dust in such debris disks is thought to arise primarily from collisions between planetesimals (asteroids) and from cometary activity; however, details about the debris formation and evolution are not well understood. With the sensitivity and angular resolution of the Spitizer Space Telescope, the structures of these nearby debris disks were mapped in great detail to study the disks' spatial structures at mid- to far-infrared wavelengths. These high spatial resolution images provide unprecedented new constraints on the the dust properties in the systems and limits on the origin of dusty debris. Support for this work was provided by NASA through Contract Number 960785 issued by JPL/Caltech.

  8. Marine debris ingestion by albatrosses in the southwest Atlantic Ocean.

    Science.gov (United States)

    Jiménez, Sebastián; Domingo, Andrés; Brazeiro, Alejandro; Defeo, Omar; Phillips, Richard A

    2015-07-15

    Plastics and other marine debris affect wildlife through entanglement and by ingestion. We assessed the ingestion of marine debris by seven albatross species in the southwest Atlantic by analyzing stomach contents of birds killed in fisheries. Of the 128 specimens examined, including four Diomedea species (n=78) and three Thalassarche species (n=50), 21 (16.4%) contained 1-4 debris items, mainly in the ventriculus. The most common type was plastic fragments. Debris was most frequent in Diomedea species (25.6%) and, particularly, Diomedea sanfordi (38.9%) and very rare in Thalassarche species (2.0%), presumably reflecting differences in foraging behavior or distribution. Frequency of occurrence was significantly higher in male than female Diomedea albatrosses (39.3% vs. 18.0%). Although levels of accumulated debris were relatively low overall, and unlikely to result in gut blockage, associated toxins might nevertheless represent a health risk for Diomedea albatrosses, compounding the negative impact of other human activities on these threatened species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Biological sulfate removal from gypsum contaminated construction and demolition debris.

    Science.gov (United States)

    Kijjanapanich, Pimluck; Annachhatre, Ajit P; Esposito, Giovanni; van Hullebusch, Eric D; Lens, Piet N L

    2013-12-15

    Construction and demolition debris (CDD) contains high levels of sulfate that can cause detrimental environmental impacts when disposed without adequate treatment. In landfills, sulfate can be converted to hydrogen sulfide under anaerobic conditions. CDD can thus cause health impacts or odor problems to landfill employees and surrounding residents. Reduction of the sulfate content of CDD is an option to overcome these problems. This study aimed at developing a biological sulfate removal system to reduce the sulfate content of gypsum contaminated CDD in order to decrease the amount of solid waste, to improve the quality of CDD waste for recycling purposes and to recover sulfur from CDD. The treatment leached out the gypsum contained in CDD by water in a leaching column. The sulfate loaded leachate was then treated in a biological sulfate reducing Upflow Anaerobic Sludge Blanket (UASB) reactor to convert the sulfate to sulfide. The UASB reactor was operated at 23 ± 3 °C with a hydraulic retention time and upflow velocity of 15.5 h and 0.1 m h(-1), respectively while ethanol was added as electron donor at a final organic loading rate of 3.46 g COD L(-1) reactor d(-1). The CDD leachate had a pH of 8-9 and sulfate dissolution rates of 526.4 and 609.8 mg L(-1) d(-1) were achieved in CDD gypsum and CDD sand, respectively. Besides, it was observed that the gypsum dissolution was the rate limiting step for the biological treatment of CDD. The sulfate removal efficiency of the system stabilized at around 85%, enabling the reuse of the UASB effluent for the leaching step, proving the versatility of the bioreactor for practical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Sedimentary architecture of a sub-lacustrine debris fan: Eocene Dongying Depression, Bohai Bay Basin, east China

    Science.gov (United States)

    Liu, Jianping; Xian, Benzhong; Wang, Junhui; Ji, Youliang; Lu, Zhiyong; Liu, Saijun

    2017-12-01

    The sedimentary architectures of submarine/sublacustrine fans are controlled by sedimentary processes, geomorphology and sediment composition in sediment gravity flows. To advance understanding of sedimentary architecture of debris fans formed predominantly by debris flows in deep-water environments, a sub-lacustrine fan (Y11 fan) within a lacustrine succession has been identified and studied through the integration of core data, well logging data and 3D seismic data in the Eocene Dongying Depression, Bohai Bay Basin, east China. Six types of resedimented lithofacies can be recognized, which are further grouped into five broad lithofacies associations. Quantification of gravity flow processes on the Y11 fan is suggested by quantitative lithofacies analysis, which demonstrates that the fan is dominated by debris flows, while turbidity currents and sandy slumps are less important. The distribution, geometry and sedimentary architecture are documented using well data and 3D seismic data. A well-developed depositional lobe with a high aspect ratio is identified based on a sandstone isopach map. Canyons and/or channels are absent, which is probably due to the unsteady sediment supply from delta-front collapse. Distributary tongue-shaped debris flow deposits can be observed at different stages of fan growth, suggesting a lobe constructed by debrite tongue complexes. Within each stage of the tongue complexes, architectural elements are interpreted by wireline log motifs showing amalgamated debrite tongues, which constitute the primary fan elements. Based on lateral lithofacies distribution and vertical sequence analysis, it is proposed that lakefloor erosion, entrainment and dilution in the flow direction lead to an organized distribution of sandy debrites, muddy debrites and turbidites on individual debrite tongues. Plastic rheology of debris flows combined with fault-related topography are considered the major factors that control sediment distribution and fan

  11. A novel integrated method to describe dust and fine supraglacial debris and their effects on ice albedo: the case study of Forni Glacier, Italian Alps

    Science.gov (United States)

    Azzoni, R. S.; Senese, A.; Zerboni, A.; Maugeri, M.; Smiraglia, C.; Diolaiuti, G. A.

    2014-06-01

    We investigated the characteristics of sparse and fine debris coverage at the glacier melting surface and its relation to ice albedo. In spite of the abundant literature dealing with dust and black carbon deposition on glacier accumulation areas (i.e.: on snow and firn), few studies that describe the distribution and properties of fine and discontinuous debris and black carbon at the melting surface of glaciers are available. Furthermore, guidelines are needed to standardize field samplings and lab analyses thus permitting comparisons among different glaciers. We developed a protocol to (i) sample fine and sparse supraglacial debris and dust, (ii) quantify their surface coverage and the covering rate, (iii) describe composition and sedimentological properties, (iv) measure ice albedo and (v) identify the relationship between ice albedo and fine debris coverage. The procedure was tested on the Forni Glacier surface (northern Italy), in summer 2011, 2012 and 2013, when the fine debris and dust presence had marked variability in space and time (along the glacier tongue and from the beginning to the end of summer) thus influencing ice albedo: in particular the natural logarithm of albedo was found to depend on the percentage of glacier surface covered by debris. Debris and dust analyses indicate generally a local origin (from nesting rockwalls) and the organic content was locally high. Nevertheless the finding of some cenospheres suggests an anthropic contribution to the superficial dust as well. Moreover, the effect of liquid precipitation on ice albedo was not negligible, but short lasting (from 1 to 4 day long), thus indicating that also other processes affect ice albedo and ice melt rates and then some attention has to be spent analysing frequency and duration of summer rainfalls for better describing albedo and melt variability.

  12. Reduction of CO2 and orbital debris: can CO2 emission trading principles be applied to debris reduction?

    Science.gov (United States)

    Orlando, Giovanni; Kinnersley, Mark; Starke, Juergen; Hugel, Sebastian; Hartner, Gloria; Singh, Sanjay; Loubiere, Vincent; Staebler, Dominik-Markus; O'Brien-Organ, Christopher; Schwindt, Stefan; Serreau, Francois; Sharma, Mohit

    In the past years global pollution and the specific situation of global warming changes have been strongly influencing public opinion and thus obliged politicians to initiate/ negotiate in-ternational agreements to control, avoid or at least reduce the impact of CO2 emissions e.g. The Kyoto Protocol (1997) and the International Copenhagen conference on Climate Change (2009). In the orbital debris area the collision between the Iridium33 and Cosmos 2251 satel-lites in 2009 has again pushed to the forefront the discussion of the space pollution by space debris and the increasing risk of critical and catastrophic events during the nominal life time of space objects. It is shown by simulations that for Low Earth Orbits the critical debris situation is already achieved and the existing space objects will probably produce sufficient space debris elements -big enough -to support the cascade effect (Kessler Syndrome). In anal-ogy with CO2 emissions, potential recommendations / regulations to reduce the production of Space Debris or its permanence in orbit, are likely to open new markets involving Miti-gation and Removal of Space Debris. The principle approach for the CO2 emission trading model will be investigated and the applicability for the global space debris handling will be analysed. The major differences of the two markets will be derived and the consequences in-dicated. Potential alternative solutions will be proposed and discussed. For the example of the CO2 emission trading principles within EU and worldwide legal conditions for space debris (national / international laws and recommendations) will be considered as well as the commer-cial approach from the controlled situation of dedicated orders to a free / competitive market in steps. It is of interest to consider forms of potential industrial organisations and interna-tional co-operations to react on a similar architecture for the debris removal trading including incentives and penalties for the different

  13. On the influence of debris in glacier melt modelling: a new temperature-index model accounting for the debris thickness feedback

    Science.gov (United States)

    Carenzo, Marco; Mabillard, Johan; Pellicciotti, Francesca; Reid, Tim; Brock, Ben; Burlando, Paolo

    2013-04-01

    The increase of rockfalls from the surrounding slopes and of englacial melt-out material has led to an increase of the debris cover extent on Alpine glaciers. In recent years, distributed debris energy-balance models have been developed to account for the melt rate enhancing/reduction due to a thin/thick debris layer, respectively. However, such models require a large amount of input data that are not often available, especially in remote mountain areas such as the Himalaya. Some of the input data such as wind or temperature are also of difficult extrapolation from station measurements. Due to their lower data requirement, empirical models have been used in glacier melt modelling. However, they generally simplify the debris effect by using a single melt-reduction factor which does not account for the influence of debris thickness on melt. In this paper, we present a new temperature-index model accounting for the debris thickness feedback in the computation of melt rates at the debris-ice interface. The empirical parameters (temperature factor, shortwave radiation factor, and lag factor accounting for the energy transfer through the debris layer) are optimized at the point scale for several debris thicknesses against melt rates simulated by a physically-based debris energy balance model. The latter has been validated against ablation stake readings and surface temperature measurements. Each parameter is then related to a plausible set of debris thickness values to provide a general and transferable parameterization. The new model is developed on Miage Glacier, Italy, a debris cover glacier in which the ablation area is mantled in near-continuous layer of rock. Subsequently, its transferability is tested on Haut Glacier d'Arolla, Switzerland, where debris is thinner and its extension has been seen to expand in the last decades. The results show that the performance of the new debris temperature-index model (DETI) in simulating the glacier melt rate at the point scale

  14. Protecting Spacecraft Fragments from Exposure to Small Debris

    Directory of Open Access Journals (Sweden)

    V. V. Zelentsov

    2015-01-01

    Full Text Available Since the launch of the first artificial Earth satellite a large amount of space debris has been accumulated in near-earth space. This debris comprises the exhausted spacecrafts, final stages of rocket-carriers and boosters, technological space junk, consisting of the structure elements, which are separated when deploying the solar arrays, antennas etc., as well as when undocking a booster and a spacecraft. All the debris is divided into observable one of over 100 mm in size and unobservable debris. In case of possible collision with the observed debris an avoidance manoeuvre is provided. The situation with unobservable debris is worse, its dimensions ranging from 100 mm to several microns. This debris is formed as a result of explosions of dead space objects and at collisions of destroyed spacecraft fragments against each other. This debris moves along arbitrary trajectories at different speeds.At collision of a spacecraft with fragments of small-size space debris, various consequences are possible: the device can immediately fail, suffer damages, which will have effect later and damages, which break no bones to the aircraft. Anyway, the spacecraft collision with small-size debris particles is undesirable. The protective shields are used to protect the aircraft from damage. Development of shield construction is complicated because the high cost of launch makes it impossible to conduct field tests of shields in space. All the work is carried out in the laboratory, with particles having co-impact speeds up to 10 km/s (possible speeds are up to 20 km/s and spherically shaped particles of 0.8 ... 3 mm in diameter.Various materials are used to manufacture shields. These are aluminum sheet, sandwich panels, metal mesh, metal foam, and woven materials (ballistic fabric. The paper considers single-layer (from sheet metal sandwich materials and multilayer shield designs. As experimental studies show, a single-layer shield protects colliding at speeds

  15. Assessment of marine debris on the Belgian Continental Shelf.

    Science.gov (United States)

    Van Cauwenberghe, Lisbeth; Claessens, Michiel; Vandegehuchte, Michiel B; Mees, Jan; Janssen, Colin R

    2013-08-15

    A comprehensive assessment of marine litter in three environmental compartments of Belgian coastal waters was performed. Abundance, weight and composition of marine debris, including microplastics, was assessed by performing beach, sea surface and seafloor monitoring campaigns during two consecutive years. Plastic items were the dominant type of macrodebris recorded: over 95% of debris present in the three sampled marine compartments were plastic. In general, concentrations of macrodebris were quite high. Especially the number of beached debris reached very high levels: on average 6429±6767 items per 100 m were recorded. Microplastic concentrations were determined to assess overall abundance in the different marine compartments of the Belgian Continental Shelf. In terms of weight, macrodebris still dominates the pollution of beaches, but in the water column and in the seafloor microplastics appear to be of higher importance: here, microplastic weight is approximately 100 times and 400 times higher, respectively, than macrodebris weight. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Numerical modelling of floating debris in the world's oceans.

    Science.gov (United States)

    Lebreton, L C-M; Greer, S D; Borrero, J C

    2012-03-01

    A global ocean circulation model is coupled to a Lagrangian particle tracking model to simulate 30 years of input, transport and accumulation of floating debris in the world ocean. Using both terrestrial and maritime inputs, the modelling results clearly show the formation of five accumulation zones in the subtropical latitudes of the major ocean basins. The relative size and concentration of each clearly illustrate the dominance of the accumulation zones in the northern hemisphere, while smaller seas surrounded by densely populated areas are also shown to have a high concentration of floating debris. We also determine the relative contribution of different source regions to the total amount of material in a particular accumulation zone. This study provides a framework for describing the transport, distribution and accumulation of floating marine debris and can be continuously updated and adapted to assess scenarios reflecting changes in the production and disposal of plastic worldwide. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. H I debris in the IC 1459 galaxy group

    Science.gov (United States)

    Saponara, Juliana; Koribalski, Bärbel S.; Benaglia, Paula; Fernández López, Manuel

    2018-01-01

    We present H I synthesis imaging of the giant elliptical galaxy IC 1459 and its surroundings with the Australia Telescope Compact Array. Our search for extended H I emission revealed a large complex of H I clouds near IC 1459, likely to be the debris from tidal interactions with neighbouring galaxies. The total H I mass (∼109 M⊙) in the detected clouds spans 250 kpc from the north-east of the gas-rich spiral NGC 7418A to the south-east of IC 1459. The extent and mass of the H I debris, which shows rather irregular morphology and kinematics, are similar to those in other nearby groups. Together with H I clouds recently detected near two other IC 1459 group members, namely IC 5270 and NGC 7418, using phased-array feeds on the Australian Square Kilometre Array Pathfinder, the detected debris make up a significant fraction of the group's intergalactic medium.

  18. Gas in Protoplanetary and Debris Disks: Insights from UV Spectroscopy

    Science.gov (United States)

    Roberge, Aki

    2008-01-01

    Over the last two decades, observations of protoplanetary and debris disks have played an important role in the new field of extrasolar planetary studies. Many are familiar with the extensive work on the cold circumstellar dust present in these disks done using infrared and sub-millimeter photometry and spectroscopy. However. UV spectroscopy has made some unique contributions by probing the elusive but vital gas component in protoplanetary and debris disks. In this talk, I will outline our picture of the evolution of protoplanetary disks and discuss the importance of the gas component. New insights obtained from UV spectroscopy will be highlighted, as well as some new puzzles. Finally, I will touch on upcoming studies of gas in protoplanetary and debris disks, some at UV wavelengths, some at far-IR and sub-mm wavelengths.

  19. Floating tumor debris. A cause of intermittent biliary obstruction.

    Science.gov (United States)

    Roslyn, J J; Kuchenbecker, S; Longmire, W P; Tompkins, R K

    1984-11-01

    Tumor debris, free-floating in the major biliary ductal system, is a cause of intermittent biliary obstruction that has previously not been recognized. Six patients had hepatic neoplasms with episodic jaundice and/or cholangitis due to floating tumor debris. Diagnosis included metastatic adenocarcinoma of the colon (n = 3), cholangiocarcinoma (n = 1), hepatocellular carcinoma (n = 1), and cavernous hemangioma (n = 1). All patients underwent biliary exploration, with hepatic resection and transhepatic intubation in two and T-tube placement in four. One patient died in the early postoperative period, and the major complication rate in the five survivors was 0%. Four of the five survivors had no further episodes suggestive of major bile duct obstruction. Our experience emphasizes the importance of distinguishing extrahepatic obstruction secondary to tumor debris from the more common causes of jaundice in patients with tumors and suggests that safe and effective palliation can be achieved in these patients.

  20. Dynamics of Unusual Debris Flows on Martian Sand Dunes

    Science.gov (United States)

    Miyamoto, Hideaki; Dohm, James M.; Baker, Victor R.; Beyer, Ross A.; Bourke, Mary

    2004-01-01

    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(exp 2) Pa s and the yield strength of 10(exp 2) Pa can form the observed deposits with a flow rate of 0.5 cu m/s sustained over several minutes and total discharged water volume on the order of hundreds of cubic meters, which may be produced by melting a surface layer of interstitial ice within the dune deposits to several centimeters depth.

  1. The Small Size Debris Population at GEO from Optical Observations

    Science.gov (United States)

    Seitzer, Patrick; Barker, Ed; Buckalew, Brent; Burkhardt, Andrew; Cowardin, Heather; Frith, James; Kaleida, Catherine; Lederer, Susan M.; Lee, Chris H.

    2017-01-01

    We have observed the geosynchronous orbit (GEO) debris population at sizes smaller than 10 cm using optical observations with the 6.5-m Magellan telescope 'Walter Baade' at the Las Campanas Observatory in Chile. The IMACS f/2 imaging camera with a 0.5-degree diameter field of view has been used in small area surveys of the GEO regime to study the population of optically faint GEO debris. The goal is to estimate the population of GEO debris that is fainter than can be studied with 1-meter class telescopes. A significant population of objects fainter than R = 19th magnitude has been found. These objects have observed with angular rates consistent with circular orbits and orbital inclinations up to 15 degrees at GEO. A sizeable number of these objects have significant brightness variations ("flashes") during the 5-second exposure, which suggest rapid changes in the albedo-projected size product.

  2. A Review of the Recent NASA Long-Term Orbital Debris Environment Projection and Active Debris Removal Modeling Activities

    Science.gov (United States)

    Liou, J.C.

    2009-01-01

    The NASA Orbital Debris Program Office (ODPO) developed a high fidelity debris evolutionary model, LEGEND (a LEO-to-GEO Environment Debris model), in 2004 to enhance its capability to better model the near-Earth environment. LEGEND can mimic the growth of the historical debris population and project it into the future based on user-defined scenarios. The first major LEGEND study concluded that even without any future launches, the LEO population would continue to increase due to mutual collisions among existing objects. In reality, the increase will be worse than this prediction because of ongoing satellite launches and unexpected major breakups. Even with a full implementation of the commonly-adopted mitigation measures, the LEO population growth is inevitable. To preserve the near-Earth environment for future generations, active debris removal (ADR) must be considered. A follow-up LEGEND ADR study was completed recently. The main results indicate that (1) the mass and collision probability of each object can be used to establish an effective removal selection criterion and (2) a removal rate of 5 objects per year is sufficient to stabilize the LEO environment. Due to the limitation of removal techniques, however, different target selection criteria (in size, altitude, inclination, etc.) may be more practical. A careful evaluation of the effectiveness of different proposed techniques must be carried out to maximize the long-term benefit to the environment.

  3. Debris Avalanches and Debris Flows Transformed from Collapses in the Trans-Mexican Volcanic Belt, México.

    Science.gov (United States)

    Capra, L.; Macias, J.; Scott, K.; Abrams, M.; Garduño, V.

    2001-12-01

    Volcanoes of the Trans-Mexican Volcanic Belt (TMVB) have yielded numerous sector and flank collapses during Pleistocene and Holocene time. Sector collapses associated with magmatic activity have yielded debris avalanches with generally limited runout extent (e.g. Popocatépetl, Jocotitlán, and Colima volcanoes). In contrast, flank collapses (smaller failures not involving the volcano summit), both associated and unassociated with magmatic activity and correlated with intense hydrothermal alteration in ice-capped volcanoes, commonly have yielded highly mobile cohesive debris flows (e.g. Pico de Orizaba and Nevado de Toluca volcanoes). Collapse orientation in the TMVB is preferentially to the south and north-east, probably reflecting the tectonic regime of active E-W and NNW faults. The different mobilities of the flows transformed from collapses have important implications for hazard assessment. Both sector and flank collapse can yield highly mobile debris flows, but this transformation is more common in the case of the smaller failures. High mobility is related to factors such as water and clay content of the failed material, the paleotopography, and the extent of entrainment of sediment during flow (bulking). Both debris-avalanches and debris-flows are volcanic hazards that occur from both active volcanoes, as well as those that are inactive or dormant volcanoes, and may by triggered by earthquakes, precipitation, or simple gravity. There will be no precursory warning in such non-volcanic cases.

  4. Types and Origins of Debris Found on Maui Shorelines: Implications for Mitigation Policies and Strategies

    Science.gov (United States)

    Blickley, L.; Currie, J. J.; Kaufman, G. D.

    2016-02-01

    Marine debris is an identified concern for coastal areas and is known to accumulate in large quantities in the North Pacific Ocean. The proximity of the Main Hawaiian Islands to these "garbage patches" represents an ongoing concern with little understanding of debris origins or efficacy of current mitigation policies. Debris accumulation surveys were conducted monthly between October 2013 and August 2014 and daily during January 2015 at 3 beaches on Maui's coastline. Debris accumulation rates, loads, and sources varied between sites and were influenced by both environmental and anthropogenic factors. Debris accumulation was strongly influenced by the temporal scale of sampling, with daily surveys showing a significant increase in accumulation rate. Plastics were the most common debris item at each site ranging from local, land-based debris including cigarette butts, straws, and food wrappers, to foreign, ocean-based debris such as oyster spacer tubes and hagfish traps. The results of this study indicate that the passage of a tobacco free beaches bill on Maui has not significantly reduced the amount of tobacco related debris. Alternatively, a ban on plastic grocery bags has eliminated this type of debris from Maui's shorelines, with no bags found at any of the sampling sites. The wide spread origins of collected debris further suggests that mitigation strategies to reduce debris will need to take place across hundreds of local municipalities. The efficacy of marine debris policies furthermore depends on enforcement and implementation strategy, as current results suggest policy enforcement at the producer level affords more effective results than that at the consumer level. Local debris mitigation actions have nevertheless been shown to affect debris loads, and municipalities are therefore encouraged to adopt a holistic combination of policy, community-based debris removal programs, increased public awareness, and ongoing monitoring to address marine debris.

  5. As main meal for sperm whales: plastics debris.

    Science.gov (United States)

    de Stephanis, Renaud; Giménez, Joan; Carpinelli, Eva; Gutierrez-Exposito, Carlos; Cañadas, Ana

    2013-04-15

    Marine debris has been found in marine animals since the early 20th century, but little is known about the impacts of the ingestion of debris in large marine mammals. In this study we describe a case of mortality of a sperm whale related to the ingestion of large amounts of marine debris in the Mediterranean Sea (4th published case worldwide to our knowledge), and discuss it within the context of the spatial distribution of the species and the presence of anthropogenic activities in the area that could be the source of the plastic debris found inside the sperm whale. The spatial distribution modelled for the species in the region shows that these animals can be seen in two distinct areas: near the waters of Almería, Granada and Murcia and in waters near the Strait of Gibraltar. The results shows how these animals feed in waters near an area completely flooded by the greenhouse industry, making them vulnerable to its waste products if adequate treatment of this industry's debris is not in place. Most types of these plastic materials have been found in the individual examined and cause of death was presumed to be gastric rupture following impaction with debris, which added to a previous problem of starvation. The problem of plastics arising from greenhouse agriculture should have a relevant section in the conservation plans and should be a recommendation from ACCOBAMS due to these plastics' and sperm whales' high mobility in the Mediterranean Sea. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Hydrometeorological threshold conditions for debris flow initiation in Norway

    Directory of Open Access Journals (Sweden)

    N. K. Meyer

    2012-10-01

    Full Text Available Debris flows, triggered by extreme precipitation events and rapid snow melt, cause considerable damage to the Norwegian infrastructure every year. To define intensity-duration (ID thresholds for debris flow initiation critical water supply conditions arising from intensive rainfall or snow melt were assessed on the basis of daily hydro-meteorological information for 502 documented debris flow events. Two threshold types were computed: one based on absolute ID relationships and one using ID relationships normalized by the local precipitation day normal (PDN. For each threshold type, minimum, medium and maximum threshold values were defined by fitting power law curves along the 10th, 50th and 90th percentiles of the data population. Depending on the duration of the event, the absolute threshold intensities needed for debris flow initiation vary between 15 and 107 mm day−1. Since the PDN changes locally, the normalized thresholds show spatial variations. Depending on location, duration and threshold level, the normalized threshold intensities vary between 6 and 250 mm day−1. The thresholds obtained were used for a frequency analysis of over-threshold events giving an estimation of the exceedance probability and thus potential for debris flow events in different parts of Norway. The absolute thresholds are most often exceeded along the west coast, while the normalized thresholds are most frequently exceeded on the west-facing slopes of the Norwegian mountain ranges. The minimum thresholds derived in this study are in the range of other thresholds obtained for regions with a climate comparable to Norway. Statistics reveal that the normalized threshold is more reliable than the absolute threshold as the former shows no spatial clustering of debris flows related to water supply events captured by the threshold.

  7. Fission-product releases from a PHWR terminal debris bed

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M.J.; Bailey, D.G., E-mail: morgan.brown@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    During an unmitigated severe accident in a pressurized heavy water reactor (PHWR) with horizontal fuel channels, the core may disassemble and relocate to the bottom of the calandria vessel. The resulting heterogeneous in-vessel terminal debris bed (TDB) would likely be quenched by any remaining moderator, and some of the decay heat would be conducted through the calandria vessel shell to the surrounding reactor vault or shield tank water. As the moderator boiled off, the solid debris bed would transform into a more homogeneous molten corium pool located between top and bottom crusts. Until recently, the severe accident code MAAP-CANDU assumed that unreleased volatile and semi-volatile fission products remained in the TDB until after calandria vessel failure, due to low diffusivity through the top crust and the lack of gases or steam to flush released fission products from the debris. However, national and international experimental results indicate this assumption is unlikely; instead, high- and medium-volatility fission products would be released from a molten debris pool, and their volatility and transport should be taken into account in TDB modelling. The resulting change in the distribution of fission products within the reactor and containment, and the associated decay heat, can have significant effects upon the progression of the accident and fission-product releases to the environment. This article describes a postulated PHWR severe accident progression to generate a TDB and the effects of fission-product releases from the terminal debris, using the simple release model in the MAAP-CANDU severe accident code. It also provides insights from various experimental programs related to fission-product releases from core debris, and their applicability to the MAAP-CANDU TDB model. (author)

  8. The Relationship Between Debris and Grain Growth in Polycrystalline Ice

    Science.gov (United States)

    Rivera, A.; McCarthy, C.

    2017-12-01

    An understanding of the mechanisms of ice flow, as well as the factors that affect it, must be improved in order to make more accurate predictions of glacial melting rates, and hence, sea level rise. Both field and laboratory studies have made an association between smaller grain sizes of ice and more rapid deformation. Therefore, it is essential to understand the different factors that affect grain size. Observations from ice cores have shown a correlation between debris content in layers of ice with smaller grain sizes, whereas layers with very little debris have larger grain sizes. Static grain growth rates for both pure ice and ice containing bubbles are well constrained, but the effect of small rock/dust particles has received less attention. We tested the relationship between debris and grain growth in polycrystalline ice with controlled annealing at -5°C and microstructural characterization. Three samples, two containing fine rock powder and one without, were fabricated, annealed, and imaged over time. The samples containing powder had different initial grain sizes due to solidification temperature during fabrication. Microstructural analysis was done on all samples after initial fabrication and at various times during the anneal using a light microscope housed in a cold room. Microstructural images were analyzed by the linear-intercept method. When comparing average grain size over time between pure ice and ice with debris, it was found that the rate of growth for the pure ice was larger than the rate of growth for the ice with debris at both initial grain sizes. These results confirm the observations seen in nature, and suggest that small grain size is indeed influenced by debris content. By understanding this, scientists could gain a more in-depth understanding of internal ice deformation and the mechanisms of ice flow. This, in turn, helps improve the accuracy of glacial melting predictions, and sea level rise in the future.

  9. Young Debris Disks With Newly Discovered Emission Features

    Science.gov (United States)

    Ballering, N.

    2014-04-01

    We analyzed the Spitzer/IRS spectra of young A and F stars that host debris disks with previously unidentified silicate emission features. Such features probe small, warm dust grains in the inner regions of these young systems where terrestrial planet formation may be proceeding (Lisse et al. 2009). For most systems, these regions are too near their host star to be directly seen with high-contrast imaging and too warm to be imaged with submillimeter interferometers. Mid-infrared excess spectra - originating from the thermal emission of the debris disk dust - remain the best data to constrain the properties of the debris in these regions. For each target, we fit physically-motivated model spectra to the data. Typical spectra of unresolved debris disks are featureless and suffer severe degeneracies between the dust location and the grain properties; however, spectra with solid-state emission features provide significantly more information, allowing for a more accurate determination of the dust size, composition, and location (e.g. Chen et al. 2006; Olofsson et al. 2012). Our results shed light on the dynamic properties occurring in the terrestrial regions of these systems. For instance, the sizes of the smallest grains and the nature of the grain size distribution reveal whether the dust originates from steady-state collisional cascades or from stochastic collisions. The properties of the dust grains - such as their crystalline or amorphous structure - can inform us of grain processing mechanisms in the disk. The location of this debris illuminates where terrestrial planet forming activity is occurring. We used results from the Beta Pictoris - which has a well-resolved debris disk with emission features (Li et al. 2012) - to place our results in context. References: Chen et al. 2006, ApJS, 166, 351 Li et al. 2012, ApJ, 759, 81 Lisse et al. 2009, ApJ, 701, 2019 Olofsson et al. 2012, A&A, 542, A90

  10. Energy balance, carbon emissions, and costs of sortyard debris disposal

    International Nuclear Information System (INIS)

    MacDonald, A.J.

    2001-01-01

    The Forest Engineering Research Institute of Canada (FERIC), with funding from Natural Resources Canada, conducted this study to determine the main environmental and energy use issues regarding the landfilling, burning or processing of dryland sortyard debris accumulated in the wood products industry. The wood residues that are generated when logs are processed, sorted and remanufactured, have traditionally been burned or landfilled. This is no longer appropriate. Converting the large woody debris into usable products such as hog fuel or compost requires grinding, smashing or chipping into small pieces to facilitate transportation. In order to make smart decisions about alternative methods of handling sortyard debris, information is needed about the comparative amount of fuel used and carbon dioxide produced. This study compared the treatment alternatives with respect to fuel consumption, net energy balance, carbon dioxide emissions and environmental impact. Recommendations were then presented for the treatment of debris from the point of view of net energy balance and environmental impact. Life cycle techniques were used to determine the environmental impact of alternatives for managing sortyard debris. It was determined that wood wastes are valuable as hog fuel for power generation. Burning hog fuel to recover its energy offsets the need to supply energy from other sources such as natural gas. This reduces the total carbon emissions by the amount of debris that would have been burned as waste. Annual carbon emissions can be reduced by nearly half by switching from a maximize burn strategy to a maximize hog strategy that combines composting of fine materials. 2 refs., 1 tab., 1 fig

  11. Detailed debris flow hazard assessment in Andorra: A multidisciplinary approach

    Science.gov (United States)

    Hürlimann, Marcel; Copons, Ramon; Altimir, Joan

    2006-08-01

    In many mountainous areas, the rapid development of urbanisation and the limited space in the valley floors have created a need to construct buildings in zones potentially exposed to debris flow hazard. In these zones, a detailed and coherent hazard assessment is necessary to provide an adequate urban planning. This article presents a multidisciplinary procedure to evaluate the debris flow hazard at a local scale. Our four-step approach was successfully applied to five torrent catchments in the Principality of Andorra, located in the Pyrenees. The first step consisted of a comprehensive geomorphologic and geologic analysis providing an inventory map of the past debris flows, a magnitude-frequency relationship, and a geomorphologic-geologic map. These data were necessary to determine the potential initiation zones and volumes of future debris flows for each catchment. A susceptibility map and different scenarios were the principal outcome of the first step, as well as essential input data for the second step, the runout analysis. A one-dimensional numerical code was applied to analyse the scenarios previously defined. First, the critical channel sections in the fan area were evaluated, then the maximum runout of the debris flows on the fan was studied, and finally simplified intensity maps for each defined scenario were established. The third step of our hazard assessment was the hazard zonation and the compilation of all the results from the two previous steps in a final hazard map. The base of this hazard map was the hazard matrix, which combined the intensity of the debris flow with its probability of occurrence and determined a certain hazard degree. The fourth step referred to the hazard mitigation and included some recommendations for hazard reduction. In Andorra, this four-step approach is actually being applied to assess the debris flow hazard. The final hazard maps, at 1 : 2000 scale, provide an obligatory tool for local land use planning. Experience

  12. Plastic debris straps on threatened blue shark Prionace glauca.

    Science.gov (United States)

    Colmenero, Ana I; Barría, Claudio; Broglio, Elisabetta; García-Barcelona, Salvador

    2017-02-15

    Juveniles of blue shark Prionace glauca caught in pelagic longlines targeting tuna and swordfish in the Atlantic Ocean and the Mediterranean Sea were found entangled with plastic straps around their gill region. The plastic debris were identified as strapping bands and caused several degrees of injuries on the dorsal musculature and pectoral fins. They were also obstructing the gill slits probably causing breathing issues. These records were uploaded in the web site seawatchers.org, and highlight the potential of citizen science in revealing the occurrence of such problems which could help to measure the effects of plastic debris on marine life. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. 170 years of debris covered glacier surface evolution

    Science.gov (United States)

    Mölg, Nico; Bolch, Tobias; Vieli, Andreas; Bauder, Andreas

    2017-04-01

    The local effect of debris layer thickness on ice melt can be studied considering short time periods and is quite well known to date. How the reduced melt, the additional weight of the debris, and the formation of ice cliffs and lakes are linked with the flow behaviour of the glacier is less well understood and much longer time periods are required for such investigations, typically in the order of the response time of the respective glacier, if possible even longer. For this reason we selected to study Zmuttgletscher in the Western Swiss Alps, which today is a heavily debris covered valley glacier. We produced a time series of glacier area, debris cover and surface elevation changes on the basis of 14 old maps and aerial images, 11 orthoimages and additional terrestrial photographs starting at the end of the little ice age (LIA) in 1859. During these 170 years the glacier lost a volume of 52.9*106 m3 (mean thickness change of -89 m) at its tongue while its debris covered area increased from about 14 to 20%. Several periods of variable retreat rates can be discerned and spatially varying change patterns become visible. Commonly the glacier has been retreating, but we can discern locally different elevation change, and also stable to positive periods in the 1980s become visible on different dynamical section of the glacier. Surface features that are commonly linked to debris cover and ice flow have emerged after the end of the LIA. For example, supraglacial thermokarst features become visible in 1880 and are widespread in the lower area of the glacier tongue in 1946. Considering big ice cliffs that are typically related to a realtively high, steep elevation difference and a large surface area, their number has increased somewhat from zero in 1859 to about 15 today. However, its the small ice cliffs, lakes and surface water channels that have emerged and also contribute to stronger melt through either exposed clean ice or ice in contact with water. Elevation

  14. A methodology for selective removal of orbital debris

    Science.gov (United States)

    Ash, R. L.; Odonoghue, P. J.; Chambers, E. J.; Raney, J. P.

    1992-01-01

    Earth-orbiting objects, large enough to be tracked, were surveyed for possible systematic debris removal. Based upon the statistical collision studies of others, it was determined that objects in orbits approximately 1000 km above the Earth's surface are at greatest collisional risk. Russian C-1B boosters were identified as the most important target of opportunity for debris removal. Currently, more than 100 in tact boosters are orbiting the Earth with apogees between 950 km and 1050 km. Using data provided by Energia USA, specific information on the C-1B booster, in terms of rendezvous and capture strategies, was discussed.

  15. Mount Baker lahars and debris flows, ancient, modern, and future

    Science.gov (United States)

    Tucker, David S; Scott, Kevin M.; Grossman, Eric E.; Linneman, Scott

    2014-01-01

    The Middle Fork Nooksack River drains the southwestern slopes of the active Mount Baker stratovolcano in northwest Washington State. The river enters Bellingham Bay at a growing delta 98 km to the west. Various types of debris flows have descended the river, generated by volcano collapse or eruption (lahars), glacial outburst floods, and moraine landslides. Initial deposition of sediment during debris flows occurs on the order of minutes to a few hours. Long-lasting, down-valley transport of sediment, all the way to the delta, occurs over a period of decades, and affects fish habitat, flood risk, gravel mining, and drinking water.

  16. Engineering and Technology Challenges for Active Debris Removal

    Science.gov (United States)

    Liou, Jer-Chyi

    2011-01-01

    After more than fifty years of space activities, the near-Earth environment is polluted with man-made orbital debris. The collision between Cosmos 2251 and the operational Iridium 33 in 2009 signaled a potential collision cascade effect, also known as the "Kessler Syndrome", in the environment. Various modelling studies have suggested that the commonly-adopted mitigation measures will not be sufficient to stabilize the future debris population. Active debris removal must be considered to remediate the environment. This paper summarizes the key issues associated with debris removal and describes the technology and engineering challenges to move forward. Fifty-four years after the launch of Sputnik 1, satellites have become an integral part of human society. Unfortunately, the ongoing space activities have left behind an undesirable byproduct orbital debris. This environment problem is threatening the current and future space activities. On average, two Shuttle window panels are replaced after every mission due to damage by micrometeoroid or orbital debris impacts. More than 100 collision avoidance maneuvers were conducted by satellite operators in 2010 to reduce the impact risks of their satellites with respect to objects in the U.S. Space Surveillance Network (SSN) catalog. Of the four known accident collisions between objects in the SSN catalog, the last one, collision between Cosmos 2251 and the operational Iridium 33 in 2009, was the most significant. It was the first ever accidental catastrophic destruction of an operational satellite by another satellite. It also signaled the potential collision cascade effect in the environment, commonly known as the "Kessler Syndrome," predicted by Kessler and Cour-Palais in 1978 [1]. Figure 1 shows the historical increase of objects in the SSN catalog. The majority of the catalog objects are 10 cm and larger. As of April 2011, the total objects tracked by the SSN sensors were more than 22,000. However, approximately 6000 of

  17. EXCALIBIR - A space experiment in orbital debris lethality

    Science.gov (United States)

    Culp, Robert D.; Dickey, Michael R.

    1991-01-01

    The study proposes a space experiment using extended Space Shuttle external tanks to test the impact of orbital debris. The External Tank Calibrated Impact Response test, EXCALIBIR, is a low-cost low-risk, high-payoff approach to investigating the threat to resident space objects posed by untrackable orbital debris, to provide lethality data to the kinetic energy weapons community, and to aid in the testing of space and missile interceptor technology. This experiment is a feasible use of existing assets - the external tank, observation and data collection facilities, launch facilities, and interceptor technology and tests planned for other programs.

  18. Active Debris Removal System Based on Polyurethane Foam

    Science.gov (United States)

    Rizzitelli, Federico; Valdatta, Marcelo; Bellini, Niccolo; Candini Gian, Paolo; Rastelli, Davide; Romei, Fedrico; Locarini, Alfredo; Spadanuda, Antonio; Bagassi, Sara

    2013-08-01

    Space debris is an increasing problem. The exponential increase of satellite launches in the last 50 years has determined the problem of space debris especially in LEO. The remains of past missions are dangerous for both operative satellites and human activity in space. But not only: it has been shown that uncontrolled impacts between space objects can lead to a potentially dangerous situation for civil people on Earth. It is possible to reach a situation of instability where the big amount of debris could cause a cascade of collisions, the so called Kessler syndrome, resulting in the infeasibility of new space missions for many generations. Currently new technologies for the mitigation of space debris are under study: for what concerning the removal of debris the use of laser to give a little impulse to the object and push it in a graveyard orbit or to be destroyed in the atmosphere. Another solution is the use of a satellite to rendezvous with the space junk and then use a net to capture it and destroy it in the reentry phase. In a parallel way the research is addressed to the study of deorbiting solutions to prevent the formation of new space junk. The project presented in this paper faces the problem of how to deorbit an existing debris, applying the studies about the use of polyurethane foam developed by Space Robotic Group of University of Bologna. The research is started with the Redemption experiment part of last ESA Rexus program. The foam is composed by two liquid components that, once properly mixed, trig an expansive reaction leading to an increase of volume whose entity depends on the chemical composition of the two starting components. It is possible to perform two kind of mission: 1) Not controlled removal: the two components are designed to react producing a low density, high expanded, spongy foam that incorporates the debris. The A/m ratio of the debris is increased and in this way also the ballistic parameter. As a consequence, the effect of

  19. Emerging insights into the dynamics of submarine debris flows

    Directory of Open Access Journals (Sweden)

    A. Elverhøi

    2005-01-01

    Full Text Available Recent experimental and theoretical work on the dynamics of submarine debris flows is summarized. Hydroplaning was first discovered in laboratory flows and later shown to likely occur in natural debris flows as well. It is a prime mechanism for explaining the extremely long runout distances observed in some natural debris flows even of over-consolidated clay materials. Moreover, the accelerations and high velocities reached by the flow head in a short time appear to fit well with the required initial conditions of observed tsunamis as obtained from back-calculations. Investigations of high-speed video recordings of laboratory debris flows were combined with measurements of total and pore pressure. The results are pointing towards yet another important role of ambient water: Water that intrudes from the water cushion underneath the hydroplaning head and through cracks in the upper surface of the debris flow may drastically soften initially stiff clayey material in the 'neck' of the flow, where significant stretching occurs due to the reduced friction at the bottom of the hydroplaning head. This self-reinforcing process may lead to the head separating from the main body and becoming an 'outrunner' block as clearly observed in several natural debris flows. Comparison of laboratory flows with different material composition indicates a gradual transition from hydroplaning plug flows of stiff clay-rich material, with a very low suspension rate, to the strongly agitated flow of sandy materials that develop a pronounced turbidity current. Statistical analysis of the great number of distinguishable lobes in the Storegga slide complex reveals power-law scaling behavior of the runout distance with the release mass over many orders of magnitude. Mathematical flow models based on viscoplastic material behavior (e.g. BING successfully reproduce the observed scaling behavior only for relatively small clay-rich debris flows while granular (frictional models

  20. 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.

  1. Draft Updates to the Planning for Natural Disaster Debris Guidance and to Related Documents

    Science.gov (United States)

    EPA is requesting comment on the draft update of the Planning for Natural Disaster Debris Guidance, along with two other documents. This Guidance is an update of the Planning for Natural Disaster Debris guidance that EPA published in March 2008.

  2. Marine debris ingestion by coastal dolphins: what drives differences between sympatric species?

    Science.gov (United States)

    Di Beneditto, Ana Paula Madeira; Ramos, Renata Maria Arruda

    2014-06-15

    This study compared marine debris ingestion of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in a sympatric area in Atlantic Ocean. Among the 89 stomach contents samples of P. blainvillei, 14 (15.7%) contained marine debris. For S. guianensis, 77 stomach contents samples were analyzed and only one of which (1.30%) contained marine debris. The debris recovered was plastic material: nylon yarns and flexible plastics. Differences in feeding habits between the coastal dolphins were found to drive their differences regarding marine debris ingestion. The feeding activity of P. blainvillei is mainly near the sea bottom, which increases its chances of ingesting debris deposited on the seabed. In contrast, S. guianensis has a near-surface feeding habit. In the study area, the seabed is the main zone of accumulation of debris, and species with some degree of association with the sea bottom may be local bioindicators of marine debris pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Debris Disks And The Search For Life In The Universe

    Science.gov (United States)

    Cataldi, Gianni

    2016-04-01

    Circumstellar debris disks are the extrasolar analogues of the asteroid belt and the Kuiper belt. These disks consist of comets and leftover planetesimals that continuously collide to produce copious amounts of 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. Structures in the disks such as gaps or warps can hint at the presence of planets. Thus, the study of debris disks is an important branch of exoplanetary science. In this thesis, some aspects of debris disks are considered in detail. A handful of debris disks show observable amounts of gas besides the dust. One such case is the edge-on debris disk around the young A-type star β Pictoris, where the gas is thought to be of secondary origin, i.e. derived from the dust itself. By observing this gas, we can thus learn something about the dust, and therefore about the building blocks of planets. In paper I, spectrally resolved observations of C II emission with Herschel/HIFI are presented. The line profile is used to constrain the spatial distribution of carbon gas in the disk, which helps understanding the gas producing mechanism. In paper II, we analyse C II and O I emission detected with Herschel/PACS and find that the oxygen must be located in a relatively dense region, possibly similar to the CO clump seen by ALMA. An upcoming analysis of our ALMA C I observations will give us a clearer picture of the system. Another famous debris disk is found around the nearby, 440 Myr old A-star Fomalhaut. Its morphology is that of an eccentric debris belt with sharp edges, suggesting shaping by a planet. However, gas-dust interactions may result in a similar morphology without the need to invoke planets. We test this possibility in paper III by analysing non-detections of C II and O I emission by Herschel/PACS. We find that

  4. Earth Satellite Population Instability: Underscoring the Need for Debris Mitigation

    Science.gov (United States)

    Liou, Jer-chyi; Johnson, N. L.

    2006-01-01

    A recent study by NASA indicates that the implementation of international orbital debris mitigation measures alone will not prevent a significant increase in the artificial Earth satellite population, beginning in the second half of this century. Whereas the focus of the aerospace community for the past 25 years has been on the curtailment of the generation of long-lived orbital debris, active remediation of the current orbital debris population should now be reconsidered to help preserve near-Earth space for future generations. In particular, we show in this paper that even if launch operations were to cease today, the population of space debris would continue to grow. Further, proposed remediation techniques do not appear to offer a viable solution. We therefore recommend that, while the aerospace community maintains the current debris-limiting mission regulations and postmission disposal procedures, future emphasis should be placed on finding new remediation technologies for solving this growing problem. Since the launch of Sputnik 1, space activities have created an orbital debris environment that poses increasing impact risks to existing space systems, including human space flight and robotic missions (1, 2). Currently, more than 9,000 Earth orbiting man-made objects (including many breakup fragments), with a combined mass exceeding 5 million kilograms, are tracked by the US Space Surveillance Network and maintained in the US satellite catalog (3-5). Three accidental collisions between cataloged satellites during the period from late 1991 to early 2005 have already been documented (6), although fortunately none resulted in the creation of large, trackable debris clouds. Several studies conducted during 1991-2001 demonstrated, with assumed future launch rates, the unintended growth potential of the Earth satellite population, resulting from random, accidental collisions among resident space objects (7-13). In some low Earth orbit (LEO) altitude regimes where

  5. A new debris flow monitoring barrier to measure debris flow impact/structure/ground interaction in the Gadria torrent

    Science.gov (United States)

    Nagl, Georg; Hübl, Johannes

    2017-04-01

    Debris flow monitoring is a keystone in debris flow research. Based on the lack of investigations of the interaction of rapid mass movement and structural mitigation measures, a new monitoring system has been installed in the well monitored Gadria torrent in South Tyrol. For design of active structural measures, like check dams, the engineering task is to come to an amicable solution of all necessary subjects. Starting with the estimation of parameters of the rapid mass movement itself to the design load and finally to the foundation of the structure. At all stages big uncertainties are given. The basis for accurate design is a comprehensive approach. For this reason, a new monitoring station was built in autumn 2016, to investigate the interaction of a debris flow with the structures and the ground. Two structures unify the new monitoring system. The first, a transversal check dam, flush to channel bed, contain two weighing devices each equipped with a pore pressure sensor. One device is also able to measure the shear force additional in two directions. The second barrier similar to a debris flow breaker but only with one singe wall centered on a foundation plate, is located downstream to the first one. 14 load cells are installed on the upward front of the structure to analyze the spatial force distribution of debris flow impact pressure. Nine earth pressure sensors under the foundation of the structure deliver the earth pressure distribution. The acceleration of the construction can be measured by a 3D accelerometer installed on the top. In case of a movement, two extensometers detect any displacement. Mounted strain gauges give insights of stresses in concrete and reinforcement. Each sensor has a sampling frequency of 2400 Hz. Furthermore it is planned to measure the flow velocity distribution over flow depth too. The new monitoring station should help to acquire data for understanding the debris flow/structure/ground interaction to facilitate the improvement

  6. Spatial and temporal patterns of beetles associated with coarse woody debris in managed bottomland hardwood forests.

    Energy Technology Data Exchange (ETDEWEB)

    Ulyshen, M., D.; Hanula, J., L.; Horn, S.; Kilgo, J., C.; Moorman, C., E.

    2004-05-13

    For. Ecol. and Mgt. 199:259-272. Malaise traps were used to sample beetles in artificial canopy gaps of different size (0.13 ha, 0.26 ha, and0.50 ha) and age in a South Carolina bottomland hardwood forest. Traps were placed at the center, edge, and in the surrounding forest of each gap. Young gaps (ý 1 year) had large amounts of coarse woody debris compared to the surrounding forest, while older gaps (ý 6 years) had virtually none. The total abundance and diversity of wood-dwelling beetles (Buprestidae, Cerambycidae, Brentidae, Bostrichidae, and Curculionidae (Scolytinae and Platypodinae)) was higher in the center of young gaps than in the center of old gaps. The abundance was higher in the center of young gaps than in the surrounding forest, while the forest surrounding old gaps and the edge of old gaps had a higher abundance and diversity of wood-dwelling beetles than did the center of old gaps. There was no difference in wood-dwelling beetle abundance between gaps of different size, but diversity was lower in 0.13 ha old gaps than in 0.26 ha or 0.50 ha old gaps. We suspect that gap size has more of an effect on woodborer abundance than indicated here because malaise traps sample a limited area. The predaceous beetle family Cleridae showed a very similar trend to that of the woodborers. Coarse woody debris is an important resource for many organisms, and our results lend further support to forest management practices that preserve coarse woody debris created during timber removal.

  7. Creating a GIS-based model of marine debris "hot spots" to improve efficiency of a lobster trap debris removal program.

    Science.gov (United States)

    Martens, Justin; Huntington, Brittany E

    2012-05-01

    Debris removal programs are combatting the accumulation of derelict fishing gear and other debris in marine habitats. We analyzed 5 years of lobster trap debris removal data in Biscayne National Park, Florida to assess removal efficiency and develop spatially-explicit mapping tools to guide future removals. We generated and validated debris "hot spots" maps that combined remotely-sensed data (i.e. benthic habitat type and bathymetry) with 862 locations of previous debris collection. Our hot spot models spatially depict regions of likely debris accumulation, reducing the search area by 95% (from 332 km(2) to 18 km(2)) and encompassing 100% of the validation sites. Our analyses indicate removal contractors using sub-surface towed divers enhanced debris recovery. Additionally, the quantity of debris removed did not decrease with increased efforts, suggesting that debris supply in situ exceeds removal efforts. We conclude with the importance of coupling analysis of ongoing debris removal programs with GIS technology to improve removal efforts. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Hydrologic control on the triggering and magnitude of debris flows in alpine catchments

    OpenAIRE

    Crema, Stefano

    2014-01-01

    The present work analyzes the hydrologic conditions leading to the triggering of debris flows in an alpine region. The overall analysis has been split in two parts: the first part of the analysis has been carried out at a regional and decadal scale to improve our knowledge of rainfall thresholds for debris-flow occurrences, of the uncertainty related to rainfall estimation at debris-flow initiation sites, and of the main morphometric characteristics of debris-flow triggering locations; in ...

  9. A Numerical Study on the Effect of Debris Layer on Fretting Wear

    Directory of Open Access Journals (Sweden)

    Tongyan Yue

    2016-07-01

    Full Text Available Fretting wear is the material damage of two contact surfaces caused by micro relative displacement. Its characteristic is that debris is trapped on the contact surfaces. Depending on the material properties, the shapes of the debris, and the dominant wear mechanisms, debris can play different roles that either protect or harm interfaces. Due to the micro scale of the debris, it is difficult to obtain instantaneous information and investigate debris behavior in experiments. The Finite Element Method (FEM has been used to model the process of fretting wear and calculate contact variables, such as contact stress and relative slip during the fretting wear process. In this research, a 2D fretting wear model with a debris layer was developed to investigate the influence of debris on fretting wear. Effects of different factors such as thickness of the debris layer, Young’s modulus of the debris layer, and the time of importing the layer into the FE model were considered in this study. Based on FE results, here we report that: (a the effect of Young’s modulus of the debris layer on the contact pressure is not significant; (b the contact pressure between the debris layer and the flat specimen decreases with increasing thickness of the layer and (c by importing the debris layer in different fretting wear cycles, the debris layer shows different roles in the wear process. At the beginning of the wear cycle, the debris layer protects the contact surfaces of the first bodies (cylindrical pad and flat specimen. However, in the final cycle, the wear volumes of the debris layers exhibit slightly higher damage compared to the model without the debris layer in all considered cases.

  10. The Range Safety Debris Catalog Analysis in Preparation for the Pad Abort One Flight Test

    Science.gov (United States)

    Kutty, Prasad; Pratt, William

    2010-01-01

    With each flight test a Range Safety Data Package is assembled to understand the potential consequences of various failure scenarios. Debris catalog analysis considers an overpressure failure of the Abort Motor and the resulting debris field created 1. Characterize debris fragments generated by failure: weight, shape, and area 2. Compute fragment ballistic coefficients 3. Compute fragment ejection velocities.

  11. A baseline assessment of beach debris and tar contamination in Bonaire, Southeastern Caribbean

    NARCIS (Netherlands)

    Debrot, A.O.; Rijn, van J.; Bron, P.S.; Leon, R.

    2013-01-01

    Data on beach debris and tar contamination is provided for 21 natural beach sites in Bonaire, Southeastern Caribbean. Transects amounting to a combined length of 991 m were sampled March–May 2011 and a total of 8960 debris items were collected. Highest debris and tar contamination were found on the

  12. Initiation processes for run-off generated debris flows in the Wenchuan earthquake area of China

    NARCIS (Netherlands)

    Hu, W.; Dong, X. J.; Xu, Q.; Wang, G. H.; van Asch, T. W J; Hicher, P. Y.

    2016-01-01

    The frequency of huge debris flows greatly increased in the epicenter area of the Wenchuan earthquake. Field investigation revealed that runoff during rainstorm played a major role in generating debris flows on the loose deposits, left by coseismic debris avalanches. However, the mechanisms of these

  13. Rainfall-triggering response patterns of post-seismic debris flows in the Wenchuan earthquake area

    NARCIS (Netherlands)

    Zhou, W.; Tang, C.; van Asch, Th.W.J.; Zhou, nn.

    2013-01-01

    Several giant debris flows occurred in southwestern China after the Wenchuan earthquake, causing serious casualties and economic losses. Debris flows were frequently triggered after the earthquake. A relatively accurate prediction of these post-seismic debris flows can help to reduce the consequent

  14. Assessing debris flow activity in a changing climate : open access

    NARCIS (Netherlands)

    Turkington, T.; Remaitre, A.; Ettema, J.; Hussin, H.Y.; van Westen, C.J.

    2016-01-01

    Future trends in debris flow activity are constructed based on bias-corrected climate change projections using two meteorological proxies: daily precipitation and Convective Available Potential Energy (CAPE) combined with specific humidity for two Alpine areas. Along with a comparison between

  15. Measuring the gypsum content of C&D debris fines.

    Science.gov (United States)

    Musson, Stephen E; Xu, Qiyong; Townsend, Timothy G

    2008-11-01

    Construction and demolition (C&D) debris recycling facilities often produce a screened material intended for use as alternative daily cover (ADC) at active landfills or for shaping and grading at closed landfills. This product contains soil and small pieces of wood, concrete, gypsum drywall, shingles and other components of C&D debris. Concerns have been raised over the contribution of gypsum drywall in C&D debris fines to odor problems at landfills where the product is used. To address such concerns, limitations may be placed on the percentage of gypsum (or sulfate) that can occur, and standardized testing procedures are required to permit valid compliance testing. A test procedure was developed for measuring the gypsum content in C&D debris fines. The concentration of sulfate leached in an aqueous solution was used to estimate the initial gypsum content of the sample. The impact of sample size and leaching time were evaluated. Precision and accuracy increased with increasing gypsum content. Results from replicate samples had an average relative standard deviation of 9%. The gypsum content of fines obtained from different facilities in the US varied widely from 1% to over 25%. These variations not only occurred between differing facilities, but within batches produced within a single facility.

  16. Risks of Plastic Debris : Unravelling Fact, Opinion, Perception, and Belief

    NARCIS (Netherlands)

    Koelmans, Albert A.; Besseling, Ellen; Foekema, Edwin; Kooi, Merel; Mintenig, Svenja|info:eu-repo/dai/nl/413292568; Ossendorp, Bernadette C.; Redondo-Hasselerharm, Paula E.; Verschoor, Anja; Van Wezel, Annemarie P.|info:eu-repo/dai/nl/141376074; Scheffer, Marten

    2017-01-01

    © 2017 American Chemical Society. Researcher and media alarms have caused plastic debris to be perceived as a major threat to humans and animals. However, although the waste of plastic in the environment is clearly undesirable for aesthetic and economic reasons, the actual environmental risks of

  17. Risks of Plastic Debris: Unravelling Fact, Opinion, Perception, and Belief.

    NARCIS (Netherlands)

    Koelmans, Albert A; Besseling, Ellen; Foekema, Edwin; Kooi, Merel; Mintenig, Svenja; Ossendorp, Bernadette C; Redondo-Hasselerharm, Paula E; Verschoor, Anja; van Wezel, Annemarie P; Scheffer, Marten

    2017-01-01

    Researcher and media alarms have caused plastic debris to be perceived as a major threat to humans and animals. However, although the waste of plastic in the environment is clearly undesirable for aesthetic and economic reasons, the actual environmental risks of different plastics and their

  18. Baseline for beached marine debris on Sand Island, Midway Atoll

    Science.gov (United States)

    Ribic, Christine; Seba B. Sheavly,; John Klavitter,

    2012-01-01

    Baseline measurements were made of the amount and weight of beached marine debris on Sand Island, Midway Atoll, June 2008–July 2010. On 23 surveys, 32,696 total debris objects (identifiable items and pieces) were collected; total weight was 740.4 kg. Seventy-two percent of the total was pieces; 91% of the pieces were made of plastic materials. Pieces were composed primarily of polyethylene and polypropylene. Identifiable items were 28% of the total; 88% of the identifiable items were in the fishing/aquaculture/shipping-related and beverage/household products-related categories. Identifiable items were lowest during April–August, while pieces were at their lowest during June–August. Sites facing the North Pacific Gyre received the most debris and proportionately more pieces. More debris tended to be found on Sand Island when the Subtropical Convergence Zone was closer to the Atoll. This information can be used for potential mitigation and to understand the impacts of large-scale events such as the 2011 Japanese tsunami.

  19. Apical extrusion of debris using reciprocating files and rotary ...

    African Journals Online (AJOL)

    Procedure: Sixty extracted human mandibular premolars were used. The root canals were instrumented using reciprocating (WaveOne, Reciproc, SafeSider) or rotary ... and cross‑sections, and kinematics, and this situation may influence the amount of apically extruded debris through the apical foramen.[15]. The aim of this ...

  20. Self-leveling onset criteria in debris beds

    International Nuclear Information System (INIS)

    Zhang, Bin; Harada, Tetsushi; Hirahara, Daisuke; Matsumoto, Tatsuya; Morita, Koji; Fukuda, Kenji; Yamano, Hidemasa; Suzuki, Tohru; Tobita, Yoshiharu

    2010-01-01

    In a core-disruptive accident of a sodium-cooled fast breeder reactor, core debris may settle on the core-support structure and/or in the lower inlet plenum of the reactor vessel because of rapid quenching and fragmentation of molten core materials in the subcooled sodium plenum. Coolant boiling is the mechanism driving the self-leveling of a debris bed that causes significant changes in the heat-removal capability of the beds. In the present study, we develop criteria establishing the onset of this self-leveling behavior that we base on a force balance model assuming a debris bed with a single-sized spherical particle. The model considers drag, buoyancy, and gravity acting on each particle. A series of experiments with simulant materials verified the applicability of this description of self-leveling. Particle size (between 0.5-6 mm), shape (spherical and nonspherical), density (namely of alumina, zirconia, lead, and stainless steel), along with boiling intensity, bed volume, and even experimental methods were taken into consideration to obtain general characteristics of the self-leveling process. We decided to use depressurization boiling to simulate an axially increasing void distribution in the debris bed, although bottom heating was also used to validate the use of the depressurization method. On the self-leveling onset issues, we obtained good agreement between model predictions and experimental results. Extrapolation of our model to actual reactor conditions is discussed. (author)

  1. Evolving Solutions to TSP Variants for Active Space Debris Removal

    NARCIS (Netherlands)

    Izzo, D.; Getzner, I.; Hennes, D.; Simões, L.F.; Silva, S.

    2015-01-01

    The space close to our planet is getting more and more polluted. Orbiting debris are posing an increasing threat to operational orbits and the cascading effect, known as Kessler syndrome, may result in a future where the risk of orbiting our planet at some altitudes will be unacceptable. Many argue

  2. Infrasonic and seismic signals of snow avalanches and debris flow

    Science.gov (United States)

    Kogelnig, Arnold; Suriñach, Emma; Hübl, Johannes; Vilajosana, Ignasi; Hiller, Martin; Dufour, Francois; McArdell, Brian W.

    2010-05-01

    Infrasonic and seismic signals generated by debris flows and snow avalanches are observed by microphones and seismometers, respectively, in near field. The properties of the signals obtained are presented. For debris flows, infrasonic and seismic signals are correlated and their amplitudes show a relationship with flow depth and precipitation data. During the passing of a debris flow several surges identified by ultrasonic gauges are observed in the time series and in the running spectra of infrasonic and seismic data. Both sensors detect the debris flow phenomena before reaching the sensors. Analyses in the time and frequency domains of seismic and acoustic signals from snow avalanches provide information on these natural phenomena. Although time series behaviour of infrasonic and seismic waves is similar, the time series present some differences in the information supplied. Complementarity and peculiarities of the use of these sensors for monitoring purposes are discussed in the paper. During the execution of this study infrasonic signals emitted from helicopters, airplanes and thunder were also identified and are presented

  3. Microstructure and debris fracture in amorphous Ni–P-CNT ...

    African Journals Online (AJOL)

    The results showed that amorphous Ni–P-based composite coatings produced partial crystallization and precipitation of the Ni3P phase after wear. The degree of crystallization increased with the increase in load. Abrasive debris were collected for scanning electron microscope observation, which would help understand ...

  4. Soil slips and debris flows on terraced slopes

    Directory of Open Access Journals (Sweden)

    G. B. Crosta

    2003-01-01

    Full Text Available Terraces cover large areas along the flanks of many alpine and prealpine valleys. Soil slips and soil slips-debris flows are recurrent phenomena along terraced slopes. These landslides cause damages to people, settlements and cultivations. This study investigates the processes related to the triggering of soil slip-debris flows in these settings, analysing those occurred in Valtellina (Central Alps, Italy on November 2000 after heavy prolonged rainfalls. 260 landslides have been recognised, mostly along the northern valley flank. About 200 soil slips and slumps occurred in terraced areas and a third of them evolved into debris flows. Field work allowed to recognise the settings at soil slip-debris flow source areas. Landslides affected up to 2.5 m of glacial, fluvioglacial and anthropically reworked deposits overlying metamorphic basement. Laboratory and in situ tests allowed to characterise the geotechnical and hydraulic properties of the terrains involved in the initial failure. Several stratigraphic and hydrogeologic factors have been individuated as significant in determining instabilities on terraced slopes. They are the vertical changes of physical soil properties, the presence of buried hollows where groundwater convergence occurs, the rising up of perched groundwater tables, the overflow and lateral infiltration from superficial drainage network, the runoff concentration by means of pathways and the insufficient drainage of retaining walls.

  5. Coarse woody debris metrics in a California oak woodland

    Science.gov (United States)

    William D. Tietje; Michael A. Hardy; Christopher C. Yim

    2015-01-01

    Little information is available on the metrics of coarse woody debris (CWD) in California oak woodland, most notably at the scale of the stand and woodland type. In a remote part of the National Guard Post, Camp Roberts, that has not burned in over a half century, we tallied 314 pieces of CWD in a blue oak (Quercus douglasii)-coast live oak (

  6. Coarse woody debris in oak woodlands of California.

    Science.gov (United States)

    William D. Tietje; Karen L. Waddell; Justin K. Vreeland; Charles L. Bolsinger

    2002-01-01

    An extensive forest inventory was conducted to estimate the amount and distribution of coarse woody debris (CWD) on 5.6 million ac of woodlands in California that are outside of national forests and reserved areas. Woodlands consist primarily of oak (Quercus spp.) types and are defined as forestland incapable of producing commercial quantities of...

  7. Catastrophic debris flows near Machu Picchu village (Aguas Calientes), Peru

    Czech Academy of Sciences Publication Activity Database

    Vilímek, V.; Klimeš, Jan; Vlčko, J.; Carreno, R.

    2006-01-01

    Roč. 50, č. 7 (2006), s. 1041-1052 ISSN 0943-0105 Institutional research plan: CEZ:AV0Z30460519 Keywords : debris flows * Machu Picchu Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.610, year: 2006

  8. Sampling and Analysis Plan for K Basins Debris

    Energy Technology Data Exchange (ETDEWEB)

    WESTCOTT, J.L.

    2000-06-21

    This Sampling and Analysis Plan presents the rationale and strategy for sampling and analysis activities to support removal of debris from the K-East and K-West Basins located in the 100K Area at the Hanford Site. This project is focused on characterization to support waste designation for disposal of waste at the Environmental Restoration Disposal Facility (ERDF). This material has previously been dispositioned at the Hanford Low-Level Burial Grounds or Central Waste Complex. The structures that house the basins are classified as radioactive material areas. Therefore, all materials removed from the buildings are presumed to be radioactively contaminated. Because most of the materials that will be addressed under this plan will be removed from the basins, and because of the cost associated with screening materials for release, it is anticipated that all debris will be managed as low-level waste. Materials will be surveyed, however, to estimate radionuclide content for disposal and to determine that the debris is not contaminated with levels of transuranic radionuclides that would designate the debris as transuranic waste.

  9. Mapping debris flow susceptibility using analytical network process ...

    Indian Academy of Sciences (India)

    Evangelin Ramani Sujatha

    2017-11-23

    Nov 23, 2017 ... demonstrated in this study to develop the susceptibility map can be very effective for local level planning and land management. Keywords. .... construction planning and highway planning (Neaupane and Piantanakulchai 2006), ..... to rank and assess the influence of the selected parameters on debris flow ...

  10. Rainfall Characteristics and Thresholds for Periglacial Debris Flows ...

    Indian Academy of Sciences (India)

    39

    highways, destroy houses, kill humans, and hurt pedestrians, threatening social development in the region. ...... Chengdu University of Science and Technology, Master thesis.(In Chinese). Lu R. Li DJ .... Yuan GX, Shang YJ, Lin DM (2009) Engineering Geological Properties and Stability Analysis of. Moraine Debris Sloprd ...

  11. Sampling and Analysis Plan for K Basins Debris

    International Nuclear Information System (INIS)

    WESTCOTT, J.L.

    2000-01-01

    This Sampling and Analysis Plan presents the rationale and strategy for sampling and analysis activities to support removal of debris from the K-East and K-West Basins located in the 100K Area at the Hanford Site. This project is focused on characterization to support waste designation for disposal of waste at the Environmental Restoration Disposal Facility (ERDF). This material has previously been dispositioned at the Hanford Low-Level Burial Grounds or Central Waste Complex. The structures that house the basins are classified as radioactive material areas. Therefore, all materials removed from the buildings are presumed to be radioactively contaminated. Because most of the materials that will be addressed under this plan will be removed from the basins, and because of the cost associated with screening materials for release, it is anticipated that all debris will be managed as low-level waste. Materials will be surveyed, however, to estimate radionuclide content for disposal and to determine that the debris is not contaminated with levels of transuranic radionuclides that would designate the debris as transuranic waste

  12. A statistical description of explosion produced debris dispersion

    NARCIS (Netherlands)

    Voort, M.M. van der; Weerheijm, J.

    2013-01-01

    The handling of explosives and ammunition introduces a safety risk for personnel and third parties. Accidents related to storage, transport and transshipment may result in severe injury and material damage. Dispersion of structural debris is one of the main hazards resulting from detonations inside

  13. A global inventory of small floating plastic debris

    NARCIS (Netherlands)

    Van Sebille, Erik|info:eu-repo/dai/nl/304831921; Wilcox, Chris; Lebreton, Laurent; Maximenko, Nikolai; Hardesty, Britta Denise; Van Franeker, Jan A.; Eriksen, Marcus; Siegel, David; Galgani, Francois; Law, Kara Lavender

    2015-01-01

    Microplastic debris floating at the ocean surface can harm marine life. Understanding the severity of this harm requires knowledge of plastic abundance and distributions. Dozens of expeditions measuring microplastics have been carried out since the 1970s, but they have primarily focused on the North

  14. A global inventory of small floating plastic debris

    NARCIS (Netherlands)

    Sebille, van Erik; Wilcox, Chris; Lebreton, Laurent; Maximenko, Nikolai; Hardesty, Britta Denise; Franeker, van J.A.; Eriksen, Marcus; Siegel, David; Galgani, F.; Law, Kara Lavender

    2015-01-01

    Microplastic debris floating at the ocean surface can harm marine life. Understanding the severity of this harm requires knowledge of plastic abundance and distributions. Dozens of expeditions measuring microplastics have been carried out since the 1970s, but they have primarily focused on

  15. 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.

    2016-01-01

    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 population-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.

  16. Evaluation of the Amount of Apically Extruded Debris during ...

    African Journals Online (AJOL)

    Objective: To evaluate the amount of apically extruded debris during retreatment (with or without solvent) of root canals filled by two obturation techniques. Materials and Methods: Forty‑eight root canals were prepared using ProTaper Universal F3 and filled with Gutta‑percha and AH 26 sealer using single cone or lateral ...

  17. Rainfall characteristics and thresholds for periglacial debris flows in ...

    Indian Academy of Sciences (India)

    Mingfeng Deng

    2018-02-14

    Feb 14, 2018 ... Stoffel 2012), melt water flow from glaciers or ice particle ablation .... in the centre of the downstream area. Dry ravels can be produced by frost weathering and sunlight, which are widely distributed along the slope (gra- dient of 30–35 ... Dry debris from glacier movement and frost weath- ering has been ...

  18. River Debris Management System using Off-Grid Photovoltaic Module

    Directory of Open Access Journals (Sweden)

    Saadon Intan Mastura

    2017-01-01

    Full Text Available In Malaysia, Malacca River has long been the tourism attraction in Malacca. However, due to negligence, the river has been polluted by the litters thrown by tourists and even local residents, thus reflects a negative perception on Malacca. Therefore, this paper discusses about a fully automated river debris management system development using a stand-alone photovoltaic system. The concept design is to be stand alone in the river and automatically pull debris towards it for disposal. An off-grid stand-alone photovoltaic solar panel is used as renewable energy source connected to water pump and Arduino Uno microcontroller. The water pump rotates a water wheel and at the same time moves a conveyor belt; which is connected to the water wheel by a gear for debris collection. The solar system sizing suitable for the whole system is shown in this paper. The dumpster barge is equipped with an infrared sensor to monitor maximum height for debris, and instruct Arduino Uno to turn off the water pump. This system is able to power up using solar energy on sunny days and using battery otherwise.

  19. The MASTER-99 space debris and meteoroid environment model

    Science.gov (United States)

    Klinkrad, H.; Bendisch, J.; Bunte, K. D.; Krag, H.; Sdunnus, H.; Wegener, P.

    2001-01-01

    MASTER-99 is a space debris and meteoroid environment model produced by TU Braunschweig (D), eta_max space (D), and DERA (UK) under an ESA contract. The model allows to compute particulate impact fluxes on any terrestrial target orbit up to geostationary altitudes. Flux contributions can be discriminated with respect to debris source types (catalog objects, explosion and collision fragments, NaK droplets, solid rocket motor dust and slag, impact ejecta, and surface degradation products), meteoroid source types (Divine-Staubach populations, and annual stream events), and with respect to origin and impact direction of each flux contributing particulate. Impact fluxes of meteoroids and debris down to 1 μm sizes can be determined for spherical targets, for tumbling plates, or for oriented, planar surfaces which are controlled according to standard attitude steering laws. MASTER-99 is distributed by ESA/ESOC on a CD ROM which includes user documentation, and the necessary data files, executables, and GUI driven installation scripts for the most common operating systems and computer platforms. MASTER-99 is delivered together with PROOF-99, a program for radar and optical observation forecasting. Based on the MASTER-99 population larger than 1 mm, it predicts debris detections from ground-based or space-based sensors (radars or telescopes) of user-defined system performances.

  20. On predicting debris flows in arid mountain belts

    Science.gov (United States)

    Stolle, Amelie; Langer, Maria; Blöthe, Jan Henrik; Korup, Oliver

    2015-03-01

    The use of topographic metrics for estimating the susceptibility to, and reconstructing the characteristics of, debris flows has a long research tradition, although largely devoted to humid mountainous terrain. The exceptional 2010 monsoonal rainstorms in the high-altitude mountain desert of Ladakh and Zanskar, NW India, were a painful reminder of how susceptible arid regions are to rainfall-triggered flash floods, landslides, and debris flows. The rainstorms of August 4-6 triggered numerous debris flows, killing 182 people, devastating 607 houses, and more than 10 bridges around Ladakh's capital of Leh. The lessons from this disaster motivated us to revisit methods of predicting (a) flow parameters such as peak discharge and maximum velocity from field and remote sensing data, and (b) the susceptibility to debris flows from catchment morphometry. We focus on quantifying uncertainties tied to these approaches. Comparison of high-resolution satellite images pre- and post-dating the 2010 rainstorm reveals the extent of damage and catastrophic channel widening. Computations based on these geomorphic markers indicate maximum flow velocities of 1.6-6.7 m s- 1 with runout of up to ~ 10 km on several alluvial fans that sustain most of the region's settlements. We estimate median peak discharges of 310-610 m3 s- 1, which are largely consistent with previous estimates. Monte Carlo-based error propagation for a single given flow-reconstruction method returns a variance in discharge similar to one derived from juxtaposing several different flow reconstruction methods. We further compare discriminant analysis, classification tree modelling, and Bayesian logistic regression to predict debris-flow susceptibility from morphometric variables of 171 catchments in the Ladakh Range. These methods distinguish between fluvial and debris flow-prone catchments at similar success rates, but Bayesian logistic regression allows quantifying uncertainties and relationships between potential

  1. Granular Dilatancy and its Effect on Debris-flow Dynamics

    Science.gov (United States)

    Iverson, R. M.; George, D. L.

    2012-12-01

    Landslides and debris flows commonly exhibit the effects of variable granular dilatancy, but incorporation of these effects in predictive models of debris-flow dynamics has been lacking. We have developed a depth-averaged model of debris-flow initiation and motion that includes the effects of variable dilatancy without stipulating its influence on rheology. Instead, the apparent rheology of Coulomb-frictional debris evolves during coupled evolution of the grain concentration m, basal pore-fluid pressure, flow thickness, and flow velocity. The dilatancy angle ψ plays an intermediary role in this evolution and obeys the simple relationship tan ψ = m-meq, where meq is the grain concentration in equilibrium with the ambient stress state and flow rate. Results of recent stress-controlled rheometric experiments by Boyer et al. (DOI: 10.1103/PhysRevLett.107.188301) provide our basis for estimating meq. Relaxation of m toward meq, coupled with evolution of pore pressure, allows our model to simulate a smooth transition from static limiting equilibrium of slopes to disequilibrium flow dynamics. Use of variable friction coefficients or dam-break initial conditions is unnecessary. We have evaluated predictions of our model in three ways: (1) by examining physical implications of exact solutions of simplified model equations, (2) by comparing numerical solutions with results of controlled experiments at the USGS debris-flow flume, and (3) by comparing numerical predictions with the behavior of a large (~50 million m3) debris flow that occurred at Mt. Meager, British Columbia, in 2010. Model predictions depend mostly on initial conditions, flow-path topography, and the value of a single dimensionless parameter that represents the ratio of two key timescales. One timescale governs downslope, gravity-driven motion of debris, and the other governs pore-pressure diffusion. Values of these timescales are readily calculated from source-area geometry and standard geotechnical

  2. Experimental study of head loss and filtration for LOCA debris

    International Nuclear Information System (INIS)

    Rao, D.V.; Souto, F.J.

    1996-02-01

    A series of controlled experiments were conducted to obtain head loss and filtration characteristics of debris beds formed of NUKON trademark fibrous fragments, and obtain data to validate the semi-theoretical head loss model developed in NUREG/CR-6224. A thermally insulated closed-loop test set-up was used to conduct experiments using beds formed of fibers only and fibers intermixed with particulate debris. A total of three particulate mixes were used to simulate the particulate debris. The head loss data were obtained for theoretical fiber bed thicknesses of 0.125 inches to 4.0 inches; approach velocities of 0.15 to 1.5 ft/s; temperatures of 75 F and 125 F; and sludge-to-fiber nominal concentration ratios of 0 to 60. Concentration measurements obtained during the first flushing cycle were used to estimate the filtration efficiencies of the debris beds. For test conditions where the beds are fairly uniform, the head loss data were predictable within an acceptable accuracy range by the semi-theoretical model. The model was equally applicable for both pure fiber beds and the mixed beds. Typically the model over-predicted the head losses for very thin beds and for thin beds at high sludge-to-fiber mass ratios. This is attributable to the non-uniformity of such debris beds. In this range the correlation can be interpreted to provide upper bound estimates of head loss. This is pertinent for loss of coolant accidents in boiling water reactors

  3. Debris and meteoroid proportions deduced from impact crater residue analysis

    Science.gov (United States)

    Berthoud, Lucinda; Mandeville, Jean-Claude; Durin, Christian; Borg, Janet

    1995-01-01

    This study is a further investigation of space-exposed samples recovered from the LDEF satellite and the Franco-Russian 'Aragatz' dust collection experiment on the Mir Space Station. Impact craters with diameters ranging from 1 to 900 micron were found on the retrieved samples. Elemental analysis of residues found in the impact craters was carried out using Energy Dispersive X-ray spectrometry (EDX). The analyses show evidence of micrometeoroid and orbital debris origins for the impacts. The proportions of these two components vary according to particle size and experimental position with respect to the leading edge of the spacecraft. On the LDEF leading edge 17 percent of the impacts were apparently caused by micrometeoroids and 11 percent by debris; on the LDEF trailing edge 23 percent of the impacts are apparently caused by micrometeoroids and 4 percent consist of debris particles - mostly larger than 3 micron in diameter - in elliptical orbits around the Earth. For Mir, the analyses indicate that micrometeoroids form 23 percent of impacts and debris 9 percent. However, we note that 60-70 percent of the craters are unidentifiable, so the definitive proportions of natural v. man-made particles are yet to be determined. Experiments carried out using a light gas gun to accelerate glass spheres and fragments demonstrate the influence of particle shape on crater morphology. The experiments also show that it is more difficult to analyze the residues produced by an irregular fragment than those produced by a spherical projectile. If the particle is travelling above a certain velocity, it vaporizes upon impact and no residues are left. Simulation experiments carried out with an electrostatic accelerator indicate that this limit is about 14 km/s for Fe particles impacting Al targets. This chemical analysis cut-off may bias interpretations of the relative populations of meteoroid and orbital debris. Oblique impacts and multiple foil detectors provide a higher likelihood

  4. Experimental study of head loss and filtration for LOCA debris

    Energy Technology Data Exchange (ETDEWEB)

    Rao, D.V.; Souto, F.J. [Science and Engineering Associates, Inc., Albuquerque, NM (United States)

    1996-02-01

    A series of controlled experiments were conducted to obtain head loss and filtration characteristics of debris beds formed of NUKON{trademark} fibrous fragments, and obtain data to validate the semi-theoretical head loss model developed in NUREG/CR-6224. A thermally insulated closed-loop test set-up was used to conduct experiments using beds formed of fibers only and fibers intermixed with particulate debris. A total of three particulate mixes were used to simulate the particulate debris. The head loss data were obtained for theoretical fiber bed thicknesses of 0.125 inches to 4.0 inches; approach velocities of 0.15 to 1.5 ft/s; temperatures of 75 F and 125 F; and sludge-to-fiber nominal concentration ratios of 0 to 60. Concentration measurements obtained during the first flushing cycle were used to estimate the filtration efficiencies of the debris beds. For test conditions where the beds are fairly uniform, the head loss data were predictable within an acceptable accuracy range by the semi-theoretical model. The model was equally applicable for both pure fiber beds and the mixed beds. Typically the model over-predicted the head losses for very thin beds and for thin beds at high sludge-to-fiber mass ratios. This is attributable to the non-uniformity of such debris beds. In this range the correlation can be interpreted to provide upper bound estimates of head loss. This is pertinent for loss of coolant accidents in boiling water reactors.

  5. SCDAP/RELAP5 Modeling of Heat Transfer and Flow Losses in Lower Head Porous Debris

    International Nuclear Information System (INIS)

    Coryell, E.W.; Siefken, L.J.; Paik, S.

    1998-01-01

    Designs are described for implementing models for calculating the heat transfer and flow losses in porous debris in the lower head of a reactor vessel. The COUPLE model in SCDAP/RELAP5 represents both the porous and non-porous debris that results from core material slumping into the lower head. Currently, the COUPLE model has the capability to model convective and radiative heat transfer from the surfaces of non-porous debris in a detailed manner and to model only in a simplistic manner the heat transfer from porous debris. In order to advance beyond the simplistic modeling for porous debris, designs are developed for detailed calculations of heat transfer and flow losses in porous debris. Correlations are identified for convective heat transfer in porous debris for the following modes of heat transfer; (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, and (5) film boiling. Interphase heat transfer is modeled in an approximate manner. A design is also described for implementing a model of heat transfer by radiation from debris to the interstitial fluid. A design is described for implementation of models for flow losses and interphase drag in porous debris. Since the models for heat transfer and flow losses in porous debris in the lower head are designed for general application, a design is also described for implementation of these models to the analysis of porous debris in the core region. A test matrix is proposed for assessing the capability of the implemented models to calculate the heat transfer and flow losses in porous debris. The implementation of the models described in this report is expected to improve the COUPLE code calculation of the temperature distribution in porous debris and in the lower head that supports the debris. The implementation of these models is also expected to improve the calculation of the temperature and flow distribution in porous debris in the core region

  6. Regional and local risk assessments of alluvial fans by combination of historical and geomorphological data on debris flows, the most damaging natural hazard in the Aosta Valley Region (NW-Italy)

    Science.gov (United States)

    Giardino, Marco; Ratto, Sara; Alberto, Walter; Armand, Marco; Cignetti, Martina; Palomba, Mauro; Navillod, Evelyne

    2010-05-01

    The Aosta Valley (NW-Italy) is a small alpine Region (area = 3262 km2) where alluvial fans occupy large sectors of the main valley bottom and also of the tributary valleys; most towns and villages lie in these sectors which are frequently affected by different geomorphological processes, including debris flows. For a best environmental hazard assessment and management of alluvial fans, a research project has been carried out with a particular attention to debris flows, responsible for causing major damages to human activities and infrastructures. A debris flows inventory on a regional scale has been created, combining historical data (1900 to present), technical maps and geomorphological analysis on the alluvial fans areas. A complex methodology for data collection and analysis has been organized in two different stages. As a first step, aerial photointerpretation and Digital Elevation Models (DEMs) analysis were conducted over the Aosta Valley Region to obtain a complete fans inventory and to identify the most affected sectors by debris flows. As a second step, data on debris flow events occurred in the Region has been collected from different sources, such as bibliographic and historical data, municipality hazard maps for land planning restriction and drainage basin technical studies. For each inventored debris flow, aerial photointerpretations have been performed to validate geomorphological and historical data, mostly collected during major regional flood events. Finally, the selected debris flow events has been formally organized in a GIS to perform spatial and statistical analysis. Application of the methodology to the complete Aosta Valley Region dataset involved the overcoming of some difficulties, such as: 1) correct identification of repeated events from different sources, 2) exact recognition of small phenomena by photointerpretation and 3) problems related to the rapid landforms obliteration. The preliminary results of the research activity are outlined

  7. Abundance and composition of near surface microplastics and plastic debris in the Stockholm Archipelago, Baltic Sea.

    Science.gov (United States)

    Gewert, Berit; Ogonowski, Martin; Barth, Andreas; MacLeod, Matthew

    2017-07-15

    We collected plastic debris in the Stockholm Archipelago using a manta trawl, and additionally along a transect in the Baltic Sea from the island of Gotland to Stockholm in a citizen science study. The samples were concentrated by filtration and organic material was digested using hydrogen peroxide. Suspected plastic material was isolated by visual sorting and 59 of these were selected to be characterized with Fourier transform infrared spectroscopy. Polypropylene and polyethylene were the most abundant plastics identified among the samples (53% and 24% respectively). We found nearly ten times higher abundance of plastics near central Stockholm than in offshore areas (4.2×10 5 plastics km -2 compared to 4.7×10 4 plastics km -2 ). The abundance of plastic debris near Stockholm was similar to urban areas in California, USA, and the overall abundance in the Stockholm Archipelago was similar to plastic abundance reported in the northwestern Mediterranean Sea. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Fouling assemblage of benthic plastic debris collected from Mersin Bay, NE Levantine coast of Turkey.

    Science.gov (United States)

    Gündoğdu, Sedat; Çevik, Cem; Karaca, Serkan

    2017-11-15

    The Mediterranean is an ecosystem that faces more and more microplastic pollution every day. This causes the whole of the Mediterranean to face the negative effects of plastic pollution. This study examines the state of plastic debris and fouling organisms found on it in one of the areas most affected by plastic pollution, Mersin Bay. As a result, a total of 3.88kg plastic (mean=0,97kg; n=120; 2670item/km 2 ; 86,3kg/km 2 ) was collected and based on the ATR-FTIR analysis, it was determined that this total contained 9 types of plastics. 17 different fouling species belonging to 6 phylum (Annelida, Arthropoda, Bryozoa, Chordata, Cnidaria, Mollusca) 7 class and 11 order were discovered on plastics. Spirobranchus triqueter, Hydroides sp. and Neopycnodonte cochlear were the most abundant species. In the end, the example of Mersin Bay shows that plastic debris as a substrate can contain a very high diversity of life just like natural substrates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Quench cooling of superheated debris beds in containment during LWR core meltdown accidents

    International Nuclear Information System (INIS)

    Ginsberg, T.; Chen, J.C.

    1984-01-01

    Light water reactor core meltdown accident sequence studies suggest that superheated debris beds may settle on the concrete floor beneath the reactor vessel. A model for the heat transfer processes during quench of superheated debris beds cooled by an overlying pool of water has been presented in a prior paper. This paper discusses the coolability of decay-heated debris beds from the standpoint of their transient quench characteristics. It is shown that even though a debris bed configuration may be coolable from the point of view of steady-state decay heat removal, the quench behavior from an initially elevated temperature may lead to bed melting prior to quench of the debris

  10. Superstorm Sandy marine debris wash-ups on Long Island - What happened to them?

    Science.gov (United States)

    Swanson, R Lawrence; Lwiza, Kamazima; Willig, Kaitlin; Morris, Kaitlin

    2016-07-15

    Superstorm Sandy generated huge quantities of debris in the Long Island, NY coastal zone. However, little appears to have been washed offshore to eventually be returned to Long Island's beaches as marine debris wash-ups. Information for our analysis includes debris collection statistics, very high resolution satellite images, along with wind and sea level data. Rigorous debris collection efforts along with meteorological conditions following the storm appear to have reduced the likelihood of debris wash-ups. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. An Estimation of Construction and Demolition Debris in Seoul, Korea: Waste Amount, Type, and Estimating Model.

    Science.gov (United States)

    Seo, Seongwon; Hwang, Yongwoo

    1999-08-01

    Construction and demolition (C&D) debris is generated at the site of various construction activities. However, the amount of the debris is usually so large that it is necessary to estimate the amount of C&D debris as accurately as possible for effective waste management and control in urban areas. In this paper, an effective estimation method using a statistical model was proposed. The estimation process was composed of five steps: estimation of the life span of buildings; estimation of the floor area of buildings to be constructed and demolished; calculation of individual intensity units of C&D debris; and estimation of the future C&D debris production. This method was also applied in the city of Seoul as an actual case, and the estimated amount of C&D debris in Seoul in 2021 was approximately 24 million tons. Of this total amount, 98% was generated by demolition, and the main components of debris were concrete and brick.

  12. Ingestion of plastic marine debris by longnose lancetfish (Alepisaurus ferox) in the North Pacific Ocean.

    Science.gov (United States)

    Jantz, Lesley A; Morishige, Carey L; Bruland, Gregory L; Lepczyk, Christopher A

    2013-04-15

    Plastic marine debris affects species on most trophic levels, including pelagic fish. While plastic debris ingestion has been investigated in planktivorous fish in the North Pacific Ocean, little knowledge exists on piscivorous fish. The objectives of this study were to determine the frequency of occurrence and the composition of ingested plastic marine debris in longnose lancetfish (Alepisaurus ferox), a piscivorous fish species captured in the Hawaii-based pelagic longline fishery. Nearly a quarter (47 of 192) of A. ferox sampled contained plastic marine debris, primarily in the form of plastic fragments (51.9%). No relationship existed between size (silhouette area) or amount of plastic marine debris ingested and morphometrics of A. ferox. Although A. ferox are not consumed by humans, they are common prey for fish commercially harvested for human consumption. Further research is needed to determine residence time of ingested plastic marine debris and behavior of toxins associated with plastic debris. Published by Elsevier Ltd.

  13. 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.

  14. Differential impact of marine debris ingestion during ontogenetic dietary shift of green turtles in Uruguayan waters.

    Science.gov (United States)

    Vélez-Rubio, G M; Teryda, N; Asaroff, P E; Estrades, A; Rodriguez, D; Tomás, J

    2018-02-01

    Anthropogenic debris ingestion has been reported for green turtles in all their life stages worldwide. The aim of the present study is to evaluate the marine debris ingestion by green turtles stranded in Uruguayan coast between 2005 and 2013. Debris items were categorized and quantified by frequency of occurrence, relative weight, volume and number of items. A total of 96 dead stranded turtles were analyzed and 70% presented debris in their guts. The majority of debris found were plastic, being hard plastics the most abundant in weight. We found no differences in debris ingestion in stranded turtles a long the Uruguayan coast. However we detected a negative correlation between the presence of debris and turtle's size. Smaller turtles are new recruits to neritic grounds indicating that the early juvenile stage of this species is the most vulnerable to this threat in the Southwestern Atlantic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Sources of plastic marine debris on beaches of Korea: More from the ocean than the land

    Science.gov (United States)

    Jang, Yong Chang; Lee, Jongmyoung; Hong, Sunwook; Lee, Jong Su; Shim, Won Joon; Song, Young Kyoung

    2014-06-01

    Reduction of marine debris requires knowledge of its sources. Sources of plastic marine debris found on six beaches of Korea were estimated. Samples larger than 25 mm were collected from 10 quadrats of 5 × 5 m for each beach in spring 2013. The total 752 items (12,255 g) of debris comprised fiber and fabric (415 items, 6,909 g), hard plastic (120 items, 4,316 g), styrofoam (93 items, 306 g), film (83 items, 464 g), foamed plastic other than styrofoam (21 items, 56 g), and other polymer (20 items, 204 g). With the probable sources allocated to each of 55 debris types, the source of 56% of all the collected debris appeared to be oceanbased and 44% was land-based. Priorities of policy measures to reduce marine debris should be different from regions to regions as the main sources of debris may differ.

  16. Seasonal variation of ice melting on varying layers of debris of Lirung Glacier, Langtang Valley, Nepal

    Directory of Open Access Journals (Sweden)

    M. B. Chand

    2015-05-01

    Full Text Available Glaciers in the Himalayan region are often covered by extensive debris cover in ablation areas, hence it is essential to assess the effect of debris on glacier ice melt. Seasonal melting of ice beneath different thicknesses of debris on Lirung Glacier in Langtang Valley, Nepal, was studied during three seasons of 2013–14. The melting rates of ice under 5 cm debris thickness are 3.52, 0.09, and 0.85 cm d−1 during the monsoon, winter and pre-monsoon season, respectively. Maximum melting is observed in dirty ice (0.3 cm debris thickness and the rate decreases with the increase of debris thickness. The energy balance calculations on dirty ice and at 40 cm debris thickness show that the main energy source of ablation is net radiation. The major finding from this study is that the maximum melting occurs during the monsoon season than rest of the seasons.

  17. Monitoring of Wind Turbine Gearbox Condition through Oil and Wear Debris Analysis: A Full-Scale Testing Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Shuangwen

    2016-10-01

    Despite the wind industry's dramatic development during the past decade, it is still challenged by premature turbine subsystem/component failures, especially for turbines rated above 1 MW. Because a crane is needed for each replacement, gearboxes have been a focal point for improvement in reliability and availability. Condition monitoring (CM) is a technique that can help improve these factors, leading to reduced turbine operation and maintenance costs and, subsequently, lower cost of energy for wind power. Although technical benefits of CM for the wind industry are normally recognized, there is a lack of published information on the advantages and limitations of each CM technique confirmed by objective data from full-scale tests. This article presents first-hand oil and wear debris analysis results obtained through tests that were based on full-scale wind turbine gearboxes rated at 750 kW. The tests were conducted at the 2.5-MW dynamometer test facility at the National Wind Technology Center at the National Renewable Energy Laboratory. The gearboxes were tested in three conditions: run-in, healthy, and damaged. The investigated CM techniques include real-time oil condition and wear debris monitoring, both inline and online sensors, and offline oil sample and wear debris analysis, both onsite and offsite laboratories. The reported results and observations help increase wind industry awareness of the benefits and limitations of oil and debris analysis technologies and highlight the challenges in these technologies and other tribological fields for the Society of Tribologists and Lubrication Engineers and other organizations to help address, leading to extended gearbox service life.

  18. Phosphorus transformations at the sediment-water interface in shallow freshwater ecosystems caused by decomposition of plant debris.

    Science.gov (United States)

    Zhang, Wenqiang; Jin, Xin; Meng, Xin; Tang, Wenzhong; Shan, Baoqing

    2018-03-03

    We studied the processes and mechanisms that drove phosphorus (P) release and transformations at the sediment-water interface (SWI) because of the decomposition of plant debris. The results showed that, as the simulation time increased, the pH, dissolved oxygen (DO), and oxidation reduction potential (ORP) in Duckweed+Sediment+Water (DWS) and Duckweed+Water (DW) initially decreased and then increased before stabilizing. Changes in the physicochemical characteristics affect the microhabitat and the release and transformations of P at the SWI. The initial flux of total P (TP), total dissolved phosphorus (TDP), and soluble reactive phosphorus (SRP) was 886, 515, and 441 mg m -2 d -1 in DWS and 626, 376, and 330 mg m -2 d -1 in DW, respectively. As the plant debris decomposed, the fluxes of TP, TDP, and SRP decreased, and after 11 days, the fluxes remained at around 0 mg m -2 d -1 . The dissolved organic phosphorus (DOP) flux followed different trends in DWS and DW, and increased first to a maximum of 285 and 109 mg m -2 d -1 , respectively, by day 6. The results of this study indicate that plant debris decomposition drive P transformations at the SWI in shallow freshwater ecosystems. Therefore, to control internal sources and transformations of P, plant debris should be removed and harvested. This study also indicates that intervention is needed to ensure the health of freshwater ecosystems, and we cannot hope to get satisfactory results from only improving the national wastewater discharge standards. Copyright © 2018. Published by Elsevier Ltd.

  19. Drone Use in Monioring Open Ocean Surface Debris, Including Paired Manta and Tucker Trawls for Relateing Sea State to Vertical Debris Distribution

    Science.gov (United States)

    Lattin, G.

    2016-02-01

    Monitoring debris at sea presents challenges not found in beach or riverine habitats, and is typically done with trawl nets of various apertures and mesh sizes, which limits the size of debris captured and the area surveyed. To partially overcome these limitations in monitoring floating debris, a Quadcopter drone with video transmitting and recording capabilities was deployed at the beginning and the end of manta trawl transects within the North Pacific Subtropical Gyre's eastern convergence zone. Subsurface tucker trawls at 10 meters were conducted at the same time as the manta trawls, in order to assess the effect of sea state on debris dispersal. Trawls were conducted on an 11 station grid used repeatedly since 1999. For drone observations, the operator and observer were stationed on the mother ship while two researchers collected observed debris using a rigid inflatable boat (RIB). The drone was flown to a distance of approximately 100 meters from the vessel in a zigzag or circular search pattern. Here we examine issues arising from drone deployment during the survey: 1) relation of area surveyed by drone to volume of water passing through trawl; 2) retrieval of drone-spotted and associated RIB spotted debris. 3) integrating post- flight image analysis into retrieved debris quantification; and 4) factors limiting drone effectiveness at sea. During the survey, debris too large for the manta trawl was spotted by the drone, and significant debris not observed using the drone was recovered by the RIB. The combination of drone sightings, RIB retrieval, and post flight image analysis leads to improved monitoring of debris at sea. We also examine the issue of the distribution of floating debris during sea states varying from 0-5 by comparing quantities from surface manta trawls to the tucker trawls at a nominal depth of 10 meters.

  20. On the measure of large woody debris in an alpine catchment

    Science.gov (United States)

    D'Agostino, V.; Bertoldi, G.; Rigon, E.

    2012-04-01

    The management of large woody debris (LWD) in Alpine torrents is a complex and ambiguous task. On one side the presence of LWD contributes to in-channel and floodplain morphological processes and plays an important role in landscape ecology and biodiversity. On the other side LWD increases considerably flood hazards when some river cross-sections result critical for the human interface (e.g. culverts, bridges, artificial channels). Only few studies provide quantitative data of LWD volumes in Alpine torrents. Research is needed both at basin scale processes (LWD recruiting from hillslopes) and at channel scale processes (feeding from river bank, storage/transport/deposition of LWD along the river bed). Our study proposes an integrate field survey methodology to assess the overall LWD amount which can be entrained by a flood. This knowledge is mandatory for the scientific research, for the implementation of LWD transport models, and for a complete hazard management in mountain basins. The study site is the high-relief basin of the Cordevole torrent (Belluno Province, Central Alps, Italy) whose outlet is located at the Saviner village (basin area of 109 square kilometers). In the November 1966 an extreme flood event occurred and some torrent reaches were heavily congested by LWD enhancing the overall damages due to long-duration overflows. Currently, the LWD recruitment seems to be strictly correlated with bank erosion and hillslope instability and the conditions of forest stand suggest LWD hazard is still high. Previous studies on sub-catchments of the Cordevole torrent have also shown an inverse relation between the drainage area and the LWD storage in the river-bed. Present contribution analyzes and quantifies the presence of LWD in the main valley channel of the Cordevole basin. A new sampling methodology was applied to integrate surveys of riparian vegetation and LWD storage. Data inventory confirms the previous relationship between LWD volumes and drainage area

  1. Floating Marine Debris in waters of the Mexican Central Pacific.

    Science.gov (United States)

    Díaz-Torres, Evelyn R; Ortega-Ortiz, Christian D; Silva-Iñiguez, Lidia; Nene-Preciado, Alejandro; Orozco, Ernesto Torres

    2017-02-15

    The presence of marine debris has been reported recently in several oceans basins; there is very little information available for Mexican Pacific coasts, however. This research examined the composition, possible sources, distribution, and density of Floating Marine Debris (FMD) during nine research surveys conducted during 2010-2012 in the Mexican Central Pacific (MCP). Of 1820 floating objects recorded, 80% were plastic items. Sources of FMD were determined using key objects, which indicated that the most were related to the presence of the industrial harbor and of a growing fishing industry in the study area. Densities were relatively high, ranging from 40 to 2440objects/km 2 ; the highest densities were recorded in autumn. FMD were distributed near coastal regions, mainly in Jalisco, influenced by river outflow and surface currents. Our results seem to follow worldwide trends and highlight the need for further studies on potential ecological impacts within coastal waters of the MCP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Tracking the debris cloud from a Chinese nuclear test

    International Nuclear Information System (INIS)

    Peterson, K.R.

    1977-01-01

    As the radioactive debris cloud from a Chinese nuclear test on September 26, 1976 began drifting eastward, the Laboratory's computational facilities were pressed into service to predict the possible environmental effects. ERDA asked us to calculate cloud trajectories and to estimate the fallout dose. The FAA asked us to provide dose estimates both for commercial aircraft flights within the U.S. and for transatlantic flights of the Concorde SST. Our dose estimates, calculated with 2BPUFF, a large-cloud diffusion code, proved to be accurate predictions, correlating well with later observations. At FAA and ERDA request, we also worked with EG and G to measure cabin dose rates in some transatlantic SST and subsonic flights while the debris cloud moved out over the Atlantic Ocean

  3. Plastic debris retention and exportation by a mangrove forest patch.

    Science.gov (United States)

    Ivar do Sul, Juliana A; Costa, Monica F; Silva-Cavalcanti, Jacqueline S; Araújo, Maria Christina B

    2014-01-15

    An experiment observed the behavior of selected tagged plastic items deliberately released in different habitats of a tropical mangrove forest in NE Brazil in late rainy (September) and late dry (March) seasons. Significant differences were not reported among seasons. However, marine debris retention varied among habitats, according to characteristics such as hydrodynamic (i.e., flow rates and volume transported) and relative vegetation (Rhizophora mangle) height and density. The highest grounds retained significantly more items when compared to the borders of the river and the tidal creek. Among the used tagged items, PET bottles were more observed and margarine tubs were less observed, being easily transported to adjacent habitats. Plastic bags were the items most retained near the releasing site. The balance between items retained and items lost was positive, demonstrating that mangrove forests tend to retain plastic marine debris for long periods (months-years). Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Modeling the long-term evolution of space debris

    Science.gov (United States)

    Nikolaev, Sergei; De Vries, Willem H.; Henderson, John R.; Horsley, Matthew A.; Jiang, Ming; Levatin, Joanne L.; Olivier, Scot S.; Pertica, Alexander J.; Phillion, Donald W.; Springer, Harry K.

    2017-03-07

    A space object modeling system that models the evolution of space debris is provided. The modeling system simulates interaction of space objects at simulation times throughout a simulation period. The modeling system includes a propagator that calculates the position of each object at each simulation time based on orbital parameters. The modeling system also includes a collision detector that, for each pair of objects at each simulation time, performs a collision analysis. When the distance between objects satisfies a conjunction criterion, the modeling system calculates a local minimum distance between the pair of objects based on a curve fitting to identify a time of closest approach at the simulation times and calculating the position of the objects at the identified time. When the local minimum distance satisfies a collision criterion, the modeling system models the debris created by the collision of the pair of objects.

  5. Analysis of accelerants and fire debris using aroma detection technology

    Energy Technology Data Exchange (ETDEWEB)

    Barshick, S.A.

    1997-01-17

    The purpose of this work was to investigate the utility of electronic aroma detection technologies for the detection and identification of accelerant residues in suspected arson debris. Through the analysis of known accelerant residues, a trained neural network was developed for classifying suspected arson samples. Three unknown fire debris samples were classified using this neural network. The item corresponding to diesel fuel was correctly identified every time. For the other two items, wide variations in sample concentration and excessive water content, producing high sample humidities, were shown to influence the sensor response. Sorbent sampling prior to aroma detection was demonstrated to reduce these problems and to allow proper neural network classification of the remaining items corresponding to kerosene and gasoline.

  6. Debris Disk Studies with the ngVLA

    Science.gov (United States)

    Wilner, David; Matthews, Brenda; Matra, Luca; Kennedy, Grant; Wyatt, Mark; Greaves, Jane

    2018-01-01

    We discuss the potential for the ngVLA to advance understanding of debris disks around main-sequence stars. Since the dust-producing planetesimals that replenish these disks through collisions persist only in stable regions like belts and resonances, their locations and physical properties encode essential information about the formation of exoplanetary systems and their dynamical evolution. Observations at long millimeter wavelengths can play a special role because the large grains that dominate the emission are faithful tracers of the dust-producing planetesimals, unlike small grains seen at shorter wavelengths that are rapidly redistributed by stellar radiation and winds. Sensitive observations of debris disks with the ngVLA can (1) reveal structures resulting from otherwise inaccessible planets on wide orbits, (2) test collisional models using spectral slopes to constrain mm/cm grain size distributions, and (3) for select sources, probe the water content of exocomets using the 21 cm HI line.

  7. Statistical learning modeling method for space debris photometric measurement

    Science.gov (United States)

    Sun, Wenjing; Sun, Jinqiu; Zhang, Yanning; Li, Haisen

    2016-03-01

    Photometric measurement is an important way to identify the space debris, but the present methods of photometric measurement have many constraints on star image and need complex image processing. Aiming at the problems, a statistical learning modeling method for space debris photometric measurement is proposed based on the global consistency of the star image, and the statistical information of star images is used to eliminate the measurement noises. First, the known stars on the star image are divided into training stars and testing stars. Then, the training stars are selected as the least squares fitting parameters to construct the photometric measurement model, and the testing stars are used to calculate the measurement accuracy of the photometric measurement model. Experimental results show that, the accuracy of the proposed photometric measurement model is about 0.1 magnitudes.

  8. The Top 10 Questions for Active Debris Removal

    Science.gov (United States)

    Liou, J. -C.

    2010-01-01

    This slide presentation reviews the requirement and issues around removal of debris from the earth orbital environment. The 10 questions discussed are: 1. Which region (LEO/MEO/GEO) has the fastest projected growth rate and the highest collision activities? 2. Can the commonly-adopted mitigation measures stabilize the future environment? 3. What are the objectives of active debris removal (ADR)? 4. How can effective ADR target selection criteria to stabilize the future LEO environment be defined? 5. What are the keys to remediate the future LEO environment? 6. What is the timeframe for ADR implementation? 7. What is the effect of practical/operational constraints? 8. What are the collision probabilities and masses of the current objects? 9. What are the benefits of collision avoidance maneuvers? 10. What is the next step?

  9. Plastic debris collars: An underreported stressor in tropical reef fishes.

    Science.gov (United States)

    Nunes, Joséde Anchieta C C; Sampaio, Cláudio L S; Barros, Francisco; Leduc, Antoine O H C

    2017-10-30

    Plastic debris collar wrappings (PDCW) are involved in the frequent entanglement of several groups of marine animals. In fishes, however aside from 'ghost fishing', PDCW events are rarely documented, and no record of this occurrence exists in tropical reef fishes. Here, we present records for four species afflicted by plastic debris collars. Observations occurred during snorkeling, and included the silver mojarra Eucinostomus argenteus, Atlantic thread herring Ophistonema oglinum, tomtate grunt Haemulon aurolineatum and gray parrotfish Sparisoma axillare. While PDCW may not create an instantaneous source of mortality, our observations suggest that debilitating stress, created by reduced swimming performances, feeding and/or antipredator behavior are likely consequences for afflicted individuals. Given the importance of these performances on survival, reduction in fitness is expected. This note aims to report cases of PDCW and underscore that such interactions between fishes and plastic pollution may be more prevalent than previously expected in coastal reef habitats. Copyright © 2017. Published by Elsevier Ltd.

  10. Conjunction challenges of low-thrust geosynchronous debris removal maneuvers

    Science.gov (United States)

    Anderson, Paul V.; Schaub, Hanspeter

    2016-06-01

    The conjunction challenges of low-thrust engines for continuous thrust re-orbiting of geosynchronous (GEO) objects to super-synchronous disposal orbits are investigated, with applications to end-of-life mitigation and active debris removal (ADR) technologies. In particular, the low maneuverability of low-thrust systems renders collision avoidance a challenging task. This study investigates the number of conjunction events a low-thrust system could encounter with the current GEO debris population during a typical re-orbit to 300 km above the GEO ring. Sensitivities to thrust level and initial longitude and inclination are evaluated, and the impact of delaying the start time for a re-orbiting maneuver is assessed. Results demonstrate that the mean number of conjunctions increases hyperbolically as thrust level decreases, but timing the start of the maneuver appropriately can reduce the average conjunction rate when lower thrust levels are applied.

  11. What Next for Wood Construction/Demolition Debris?

    OpenAIRE

    Martin A. Hubbe

    2014-01-01

    Residents in localities throughout the world voluntarily participate in the routine recycling of household wastes, such as paper, metals, and plastics containers. But when a house in their neighborhood gets built or torn down, most of the debris – including wood waste – gets landfilled. Such a waste of material suggests that there are opportunities to add value to these under-utilized resources. The great variability, as well as contamination, pose major challenges. It is recommended that rec...

  12. Recycled construction debris as an aggregates. Production of concrete blocks

    OpenAIRE

    Sousa, J. G. G.; Bauer, E.; Sposto, R. M.

    2003-01-01

    This paper analyzes the use of recycled construction and demolition debris as aggregate for the construction of concrete blocks to be used in sealing masonry. Initial studies addressed the definition of parameters used in the mix of conventional materials (traditionally used in the production of concrete blocks), involving cylindrical test specimens (100x200 mm), molded with the help of a vibratory table. In addition to these definitions, and based on the mixes showing the best results, a new...

  13. Implementation of Flying Debris Fatal Risk Calculation in EUROPLEXUS

    OpenAIRE

    VALSAMOS GEORGIOS; CASADEI FOLCO; LARCHER MARTIN; SOLOMOS George

    2015-01-01

    This study presents a numerical approach for the calculation of fatality risk caused by the impact of flying debris on the human body. Following an explosion, the formation of a large number of high velocity flying fragments, especially from glass panes, is very possible. The velocity, the mass and the shape of these projectiles define their hazardousness. The developed numerical approach is integrated into fluid-structure interaction techniques, commonly used for the determination of the beh...

  14. Characterizing Debris Disks in the Late Stages of Planet Formation

    Science.gov (United States)

    White, Jacob

    2018-01-01

    The planet formation process shapes the morphology and grain size distribution of circumstellar disks, encoding the formation history of a given system. Remnants of planet formation, such as comets and asteroids, collisionally evolve and can replenish the dust and small solids that would otherwise be cleared on short timescales. These grains are observed through reprocessed starlight at submm to cm wavelengths.The spectrum of the mm/cm emission reveals details of the grain population. However, one confounding parameter in studying these grains around stars is the stars themselves. The emission from stars in the mm/cm is nontrivial and generally not well-constrained. I will present examples of debris systems (HD 141569 and Fomalhaut) studied by ALMA and the VLA, in which unconstrained stellar emission may be contributing to the observed flux densities. Such contamination in turn biases the inferred emission from the disk and the corresponding dust properties. In some cases, the behavior of the observed A/B stars can exhibit an emission profile that has similarities to that of the Sun's mm/cm emission, although the same processes are not thought to necessarily occur in the atmospheres of massive stars.To address the uncertainty in stellar emission at mm/cm wavelengths, we present ongoing radio observations (JCMT, SMA, VLA) of Sirius A, which is a bright, nearby star with no known debris. We seek to use this system to set an observationally determined standard for stellar atmosphere modeling and debris disk studies around A stars, as well as to take the first step toward characterizing potential intrinsic uncertainty in stellar emission at these wavelengths. This talk will highlight the effort to characterize stellar atmospheres through a project known as MESAS (Measuring the Emission of Stellar Atmospheres at Submillimeter/millimeter wavelengths) which is imperative to the success of current and future debris disk studies.

  15. Experimental study on the rheological behaviour of debris flow

    Directory of Open Access Journals (Sweden)

    A. Scotto di Santolo

    2010-12-01

    Full Text Available A model able to describe all the processes involved in a debris flow can be very complex owing to the sudden changing of the material that turns from solid into liquid state. The two phases of the phenomenon are analysed separately referring to soil mechanics procedures with regard to the trigger phase, and to an equivalent fluid for the post-failure phase. The present paper is devoted to show the experimental results carried out to evaluate the behaviour assumed by a pyroclastic-derived soil during the flow. A traditional fluid tool has been utilized: a standard rotational rheometer equipped with two different geometries. The soils tested belong to deposits that cover the slopes of the Campania region, Italy, often affected by debris flows. The influence of solid concentration Cv and grain size distribution was tested: the soils were destructurated, sieved and mixed with water starting from the in situ porosity. All material mixtures showed a non-Newtonian fluid behaviour with a yield stress τy that increases with a solid volumetric concentration and decreases for an increase of sand fraction. The experimental data were fitted with standard model for fluids. A simple relation between Cv and τy was obtained. The yield stress seems to be a key parameter for describing and predicting the post-failure behaviour of debris flows. These results suggest that in the field a small change in solid fraction, due to rainfall, will cause a slight decrease of the static yield stress, readily inducing a rapid flow which will stop only when the dynamic yield stress is reached, namely on a much smoother slope. This can explain the in situ observed post-failure behaviour of debris flows, which are able to flow over very long distances even on smooth slopes.

  16. Hubble Space Telescope Observations of the HD 202628 Debris Disk

    Science.gov (United States)

    Krist, John E.; Stapelfeldt, Karl R.; Bryden, Geoffrey; Plavchan, Peter

    2012-01-01

    A ring-shaped debris disk around the G2V star HD 202628 (d = 24.4 pc) was imaged in scattered light at visible wavelengths using the coronagraphic mode of the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. The ring is inclined by approx.64deg from face-on, based on the apparent major/minor axis ratio, with the major axis aligned along PA = 130deg. It has inner and outer radii (> 50% maximum surface brightness) of 139 AU and 193 AU in the northwest ansae and 161 AU and 223 AU in the southeast ((Delta)r/r approx. = 0.4). The maximum visible radial extent is approx. 254 AU. With a mean surface brightnesses of V approx. = 24 mag arcsec.(sup -2), this is the faintest debris disk observed to date in reflected light. The center of the ring appears offset from the star by approx.28 AU (deprojected). An ellipse fit to the inner edge has an eccentricity of 0.18 and a = 158 AU. This offset, along with the relatively sharp inner edge of the ring, suggests the influence of a planetary-mass companion. There is a strong similarity with the debris ring around Fomalhaut, though HD 202628 is a more mature star with an estimated age of about 2 Gyr. We also provide surface brightness limits for nine other stars in our study with strong Spitzer excesses around which no debris disks were detected in scattered light (HD 377, HD 7590, HD 38858, HD 45184, HD 73350, HD 135599, HD 145229, HD 187897, and HD 201219).

  17. HUBBLE SPACE TELESCOPE OBSERVATIONS OF THE HD 202628 DEBRIS DISK

    International Nuclear Information System (INIS)

    Krist, John E.; Bryden, Geoffrey; Stapelfeldt, Karl R.; Plavchan, Peter

    2012-01-01

    A ring-shaped debris disk around the G2V star HD 202628 (d = 24.4 pc) was imaged in scattered light at visible wavelengths using the coronagraphic mode of the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. The ring is inclined by ∼64° from face-on, based on the apparent major/minor axis ratio, with the major axis aligned along P.A. = 130°. It has inner and outer radii (>50% maximum surface brightness) of 139 AU and 193 AU in the northwest ansae and 161 AU and 223 AU in the southeast (Δr/r ≈ 0.4). The maximum visible radial extent is ∼254 AU. With mean surface brightness of V ≈ 24 mag arcsec –2 , this is the faintest debris disk observed to date in reflected light. The center of the ring appears offset from the star by ∼28 AU (deprojected). An ellipse fit to the inner edge has an eccentricity of 0.18 and a = 158 AU. This offset, along with the relatively sharp inner edge of the ring, suggests the influence of a planetary-mass companion. There is a strong similarity with the debris ring around Fomalhaut, though HD 202628 is a more mature star with an estimated age of about 2 Gyr. We also provide surface brightness limits for nine other stars in our study with strong Spitzer excesses around which no debris disks were detected in scattered light (HD 377, HD 7590, HD 38858, HD 45184, HD 73350, HD 135599, HD 145229, HD 187897, and HD 201219).

  18. Debris Hazards Due to Overloaded Conventional Construction Facades

    Science.gov (United States)

    2015-12-01

    cubic meter (m 3 ) Mass/ Density pound (lb) 4.535 924 × 10 –1 kilogram (kg) unified atomic mass unit (amu) 1.660 539 × 10 –27 kilogram (kg...hazards to buildings. This work will present results for experiments involving conventional façade materials (glass, concrete , and mason- ry) that have...been overloaded to generate debris data at the structural and material levels. The material level samples have been loaded at high pressures using a

  19. Methods of Fire Debris Preparation for Detection of Accelerants.

    Science.gov (United States)

    Caddy, B; Smith, F P; Macy, J

    1991-06-01

    Forensic scientists use various techniques to separate accelerants from fire debris samples before instrumental identification of added fuels. Among the choices available, traditional micro-distillation, steam distillation, vacuum distillation, headspace, heated headspace, and several vapor adsorption/desorption methods provide various advantages and disadvantages. This communication reviews the development of these techniques from the 1950s and comparison studies performed. Copyright © 1991 Central Police University.

  20. Resolved Millimeter Observations of the HR 8799 Debris Disk

    Science.gov (United States)

    Wilner, David J.; MacGregor, Meredith A.; Andrews, Sean M.; Hughes, A. Meredith; Matthews, Brenda; Su, Kate

    2018-03-01

    We present 1.3 mm observations of the debris disk surrounding the HR 8799 multi-planet system from the Submillimeter Array to complement archival ALMA observations that spatially filtered away the bulk of the emission. The image morphology at 3.″8 (150 au) resolution indicates an optically thin circumstellar belt, which we associate with a population of dust-producing planetesimals within the debris disk. The interferometric visibilities are fit well by an axisymmetric radial power-law model characterized by a broad width, ΔR/R ≳ 1. The belt inclination and orientation parameters are consistent with the planet orbital parameters within the mutual uncertainties. The models constrain the radial location of the inner edge of the belt to {R}in}={104}-12+8 au. In a simple scenario where the chaotic zone of the outermost planet b truncates the planetesimal distribution, this inner edge location translates into a constraint on the planet b mass of {M}pl}={5.8}-3.1+7.9 M Jup. This mass estimate is consistent with infrared observations of the planet luminosity and standard hot-start evolutionary models, with the uncertainties allowing for a range of initial conditions. We also present new 9 mm observations of the debris disk from the Very Large Array and determine a millimeter spectral index of 2.41 ± 0.17. This value is typical of debris disks and indicates a power-law index of the grain size distribution q = 3.27 ± 0.10, close to predictions for a classical collisional cascade.

  1. TMI-2 core debris analytical methods and results

    International Nuclear Information System (INIS)

    Akers, D.W.; Cook, B.A.

    1984-01-01

    A series of six grab samples was taken from the debris bed of the TMI-2 core in early September 1983. Five of these samples were sent to the Idaho National Engineering Laboratory for analysis. Presented is the analysis strategy for the samples and some of the data obtained from the early stages of examination of the samples (i.e., particle size-analysis, gamma spectrometry results, and fissile/fertile material analysis)

  2. Charging of Space Debris and Their Dynamical Consequences

    Science.gov (United States)

    2016-01-08

    satellite orbital altitudes (particularly in the low earth orbit (LEO) region) and the risk they pose for space assets has attracted a great deal of...SUPPLEMENTARY NOTES 14. ABSTRACT The charging of space debris due to the ambient plasma environment in the low earth orbit (LEO) and geostationary earth... orbit (GEO) regions of the ionosphere has been investigated using both analytic and particle-in-cell (PIC) modeling. The analytic estimates have been

  3. Characterizing Debris Disks and the Late Stages of Planet Formation

    Science.gov (United States)

    White, Jacob

    2017-10-01

    The planet formation process shapes the morphology and grain size distribution of circumstellar disks, encoding the formation history of a given system. Remnants of planet formation, such as comets and asteroids, collisionally evolve and can replenish the dust and small solids that would otherwise be cleared on short timescales. These grains are observed through reprocessed starlight at submm to cm wavelengths.The spectrum of the mm/cm emission reveals details of the grain population. However, one confounding parameter in studying these grains around stars is the stars themselves. The emission from stars in the mm/cm is nontrivial and generally not well-constrained. I will present examples of debris systems (HD 141569 and Fomalhaut) studied by ALMA and the VLA, in which unconstrained stellar emission may be contributing to the observed flux densities. Such contamination in turn biases the inferred emission from the disk and the corresponding dust properties. In some cases, the behavior of the observed A/B stars can exhibit an emission profile that has similarities to that of the Sun's mm/cm emission, although the same processes are not thought to necessarily occur in the atmospheres of massive stars.To address the uncertainty in stellar emission at mm/cm wavelengths, we present ongoing radio observations (JCMT, SMA, VLA) of Sirius A, which is a bright, nearby star with no known debris. We seek to use this system to set an observationally determined standard for stellar atmosphere modeling and debris disk studies around A stars, as well as to take the first step toward characterizing potential intrinsic uncertainty in stellar emission at these wavelengths. This talk will highlight the effort to characterize stellar atmospheres through a project known as MESAS (Measuring the Emission of Stellar Atmospheres at Submillimeter/millimeter wavelengths) which is imperative to the success of current and future debris disk studies.

  4. Microbial hitchhikers on marine plastic debris: Human exposure risks at bathing waters and beach environments.

    Science.gov (United States)

    Keswani, Anisha; Oliver, David M; Gutierrez, Tony; Quilliam, Richard S

    2016-07-01

    Marine plastic debris is well characterized in terms of its ability to negatively impact terrestrial and marine environments, endanger coastal wildlife, and interfere with navigation, tourism and commercial fisheries. However, the impacts of potentially harmful microorganisms and pathogens colonising plastic litter are not well understood. The hard surface of plastics provides an ideal environment for opportunistic microbial colonisers to form biofilms and might offer a protective niche capable of supporting a diversity of different microorganisms, known as the "Plastisphere". This biotope could act as an important vector for the persistence and spread of pathogens, faecal indicator organisms (FIOs) and harmful algal bloom species (HABs) across beach and bathing environments. This review will focus on the existent knowledge and research gaps, and identify the possible consequences of plastic-associated microbes on human health, the spread of infectious diseases and bathing water quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Clay-associated organic matter in kaolinitic and smectitic soils

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.

    2002-01-01

    The primary source of soil organic matter is plant debris of all kinds, such as dead roots, leaves and branches that enter into the soil and are then biologically decomposed at variable rates. Organic matter has many different important functions on a local and global scale. Soil organic matter is

  6. Plastic debris ingestion by marine catfish: an unexpected fisheries impact.

    Science.gov (United States)

    Possatto, Fernanda E; Barletta, Mário; Costa, Monica F; do Sul, Juliana A Ivar; Dantas, David V

    2011-05-01

    Plastic marine debris is a pervasive type of pollution. River basins and estuaries are a source of plastics pollution for coastal waters and oceans. Estuarine fauna is therefore exposed to chronic plastic pollution. Three important catfish species [Cathorops spixii (N=60), Cathorops agassizii (N=60) and Sciades herzbergii (N=62)] from South Western Atlantic estuaries were investigated in a tropical estuary of the Brazilian Northeast in relation to their accidental ingestion of plastic marine debris. Individuals from all three species had ingested plastics. In C. spixii and C. agassizii, 18% and 33% of individuals had plastic debris in their stomachs, respectively. S. herzbergii showed 18% of individuals were contaminated. All ontogenetic phases (juveniles, sub-adults and adults) were contaminated. Nylon fragments from cables used in fishery activities (subsistence, artisanal and commercial) played a major role in this contamination. These catfish spend their entire life cycles within the estuary and are an important feeding resource for larger, economically important, species. It is not yet possible to quantify the scale and depth of the consequences of this type of pollution. However, plastics are well known threat to living resources in this and other estuaries. Conservation actions will need to from now onto take plastics pollution into consideration. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Wear debris. An environmental issue in total joint replacement.

    Science.gov (United States)

    Manley, M T; Serekian, P

    1994-01-01

    There is a growing concern that osteolytic lesions, often adjacent to otherwise stable implants, are a recent phenomenon caused by some recent change in polyethylene, metal, or other aspect of the total hip construction. This study investigates the possibility that bearings and modular connections used in modern hip replacements are an unappreciated source of particulate debris. Measurements taken from contemporary femoral bearings show a significant mismatch in both surface finish and sphericity of mating metal and polyethylene components, with sphericity of inserts being much worse then sphericity of femoral heads. The tolerances for sphericity of polyethylene inserts were further changed by the placement of an insert into its metal shell. Hip simulator tests of assembled inserts and shells showed greater polyethylene weight loss for metal-backed shells than for inserts alone. Bending and torsional tests of metal/metal modular connections showed that dynamic loads can release large numbers of debris particles from taper junctions. Because osteolytic lesions clearly are associated with overload of tissue by debris particles, the design, manufacture, and tolerances of modular connections in total hip replacement all seem to require reevaluation.

  8. Orbital Debris Assesment Tesing in the AEDC Range G

    Science.gov (United States)

    Polk, Marshall; Woods, David; Roebuck, Brian; Opiela, John; Sheaffer, Patti; Liou, J.-C.

    2015-01-01

    The space environment presents many hazards for satellites and spacecraft. One of the major hazards is hypervelocity impacts from uncontrolled man-made space debris. Arnold Engineering Development Complex (AEDC), The National Aeronautics and Space Administration (NASA), The United States Air Force Space and Missile Systems Center (SMC), the University of Florida, and The Aerospace Corporation configured a large ballistic range to perform a series of hypervelocity destructive impact tests in order to better understand the effects of space collisions. The test utilized AEDC's Range G light gas launcher, which is capable of firing projectiles up to 7 km/s. A non-functional full-scale representation of a modern satellite called the DebriSat was destroyed in the enclosed range enviroment. Several modifications to the range facility were made to ensure quality data was obtained from the impact events. The facility modifcations were intended to provide a high impact energy to target mass ratio (>200 J/g), a non-damaging method of debris collection, and an instrumentation suite capable of providing information on the physics of the entire imapct event.

  9. Marine debris in a World Heritage Listed Brazilian estuary.

    Science.gov (United States)

    Possatto, Fernanda E; Spach, Henry L; Cattani, André P; Lamour, Marcelo R; Santos, Lilyane O; Cordeiro, Nathalie M A; Broadhurst, Matt K

    2015-02-28

    Using monthly otter-trawl deployments, spatial and temporal variability among the relative densities of marine debris were assessed in the Paranaguá estuarine complex; a subtropical World Heritage Listed area in southern Brazil. During 432 deployments over 12 months, 291 marine debris items were identified; of which most (92%) were plastic, and more specifically shopping bags, food packages, candy wrappers and cups typically >21 mm long. The most contaminated sectors were those closest to Paranaguá city and the adjacent port, and had up to 23.37±3.22 pieces ha(-1). Less urbanized sectors had between 12.84±1.49 and 9.32±1.10 pieces ha(-1). Contamination did not vary between dry or wet seasons, but rather was probably affected by consistent urban disposal and localized hydrological processes. Marine debris might be minimized by using more environment friendly materials, however a concrete solution requires adequately integrating local government and civil society. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Development of Harpoon System for Capturing Space Debris

    Science.gov (United States)

    Reed, Jame; Barraclough, Simon

    2013-08-01

    Active removal of large space debris has been identified as a key activity to control the growth in the debris population and to limit the risk to active satellites. Astrium is developing technologies to enable such a mission, including a harpoon capture system. The harpoon is simple, compact and lightweight. Since the capture is fast (typically barbs to robustly hold the target, a crushable section to absorb excess impact energy, and a tether to connect to the chaser vehicle. The baseline firing system uses compressed gas, although a simpler one-shot system has also been designed. To understand how a harpoon could be applicable to active debris removal an on-ground prototype and test-rig has been developed for trials with real structural elements of satellites and rocket bodies. Testing has demonstrated the feasibility of the concept and this paper describes the results as well as the next steps. A number of design variants are also proposed which could simplify the system design of an ADR mission.

  11. What Sets the Radial Locations of Warm Debris Disks?

    Science.gov (United States)

    Ballering, Nicholas P.; Rieke, George H.; Su, Kate Y. L.; Gáspár, András

    2017-08-01

    The architectures of debris disks encode the history of planet formation in these systems. Studies of debris disks via their spectral energy distributions (SEDs) have found infrared excesses arising from cold dust, warm dust, or a combination of the two. The cold outer belts of many systems have been imaged, facilitating their study in great detail. Far less is known about the warm components, including the origin of the dust. The regularity of the disk temperatures indicates an underlying structure that may be linked to the water snow line. If the dust is generated from collisions in an exo-asteroid belt, the dust will likely trace the location of the water snow line in the primordial protoplanetary disk where planetesimal growth was enhanced. If instead the warm dust arises from the inward transport from a reservoir of icy material farther out in the system, the dust location is expected to be set by the current snow line. We analyze the SEDs of a large sample of debris disks with warm components. We find that warm components in single-component systems (those without detectable cold components) follow the primordial snow line rather than the current snow line, so they likely arise from exo-asteroid belts. While the locations of many warm components in two-component systems are also consistent with the primordial snow line, there is more diversity among these systems, suggesting additional effects play a role.

  12. Pebble orientation on large, experimental debris-flow deposits

    Science.gov (United States)

    Major, J.J.

    1998-01-01

    Replicable, pronounced orientation of discoid pebbles (??? 8 mm) embedded on surfaces of large (??? 10 m3) experimental debris-flow deposits reveals that strongly aligned, imbricate fabric can develop rapidly over short distances in mass flows. Pebble long axes aligned subparallel to deposit margins as well as subparallel to margins of surge waves arrested within the deposits. Pebble alignment exhibited modes both parallel to (a(p)), and normal to (a(t)), the primary flow direction; intermediate axes dipped preferentially inward from surge-wave margins (b(i) orientation). Repetitive development of margin-parallel, imbricate fabric distributed across deposit surfaces provides compelling evidence that deposits formed dominantly through progressive incremental accretion rather than through simple en masse emplacement. Pronounced fabric along deposit and arrested surge-wave margins reflects significant grain interaction along flow margins. This sedimentological evidence for significant marginal grain interaction complements theoretical analyses (Iverson, 1997) and other experimental data (Major, 1996: Iverson, 1997) that indicate that resistance along flow margins is an important factor affecting debris-flow deposition. The fabric on the experimental deposits demonstrates that debris flows can develop strongly imbricate particle orientation that mimics fabric developed during fluvial deposition. Particle shape and local stress fields appear to have more control over fabric development than does general depositional process. Other criteria in addition to particle orientation are needed to discriminate mass flow from fluvial gravel deposits and to unravel depositional history. ?? 1998 Elsevier Science B.V. All rights reserved.

  13. Impact risk assessment for the ATV using ESABASE/DEBRIS

    Science.gov (United States)

    Beltrami Karlezi, P.; Drolshagen, G.; Lambert, M.

    2001-10-01

    The European Space Agency ESA participates in the International Space Station with various programs, one of them being the Automated Transfer Vehicle (ATV). The ATV is an unmanned servicing and logistics vehicle launched on Ariane 5 and designed to fulfil different roles like cargo transport, re-supply of fuel and consumables and orbit re-boost of the International Space Station (ISS). For this reason it is important that the risks imposed on these modules by meteoroids and orbital debris are calculated accurately. Following such calculations the Meteoroid and Orbital Debris Protection System (M/ODPS) can be optimised. This paper presents the results of the risk assessment of meteoroids and space debris for the ATV spacecraft attached to the ISS using different shield configurations. The results are presented as the probability of no penetration (PNP) for each component and each configuration. They are compared to a target PNP requirement of 0.999 for 135 days and the weight penalty produced by the extra shielding is given.

  14. The magnetorotational instability in debris-disc gas

    Science.gov (United States)

    Kral, Quentin; Latter, Henrik

    2016-09-01

    Debris discs are commonly swathed in gas, which can be observed in UV, in fine structure lines in FIR, and in resolved maps of CO emission. Carbon and oxygen are overabundant in such gas, but it is severely depleted in hydrogen. As a consequence, its ionization fraction is remarkably high, suggesting that magnetohydrodynamic (MHD) processes could be important. In particular, the gas may be subject to the magnetorotational instability (MRI), and indeed, recent modelling of β Pictoris requires an anomalous viscosity to explain the gas's observed radial structure. In this paper, we explore the possibility that the MRI is active in debris-disc gas and responsible for the observed mass transport. We find that non-ideal MHD and dust-gas interactions play a subdominant role, and that linear instability is viable at certain radii. However, owing to low gas densities, the outer parts of the disc could be stabilized by a weak ambient magnetic field, though it is difficult to constrain such a field. Even if the MRI is stabilized by too strong a field, a magnetocentrifugal wind may be launched in its place, and this could lead to equivalent (non-turbulent) transport. Numerical simulations of the vertically stratified MRI in conditions appropriate to the debris-disc gas should be able to determine the nature of the characteristic behaviour at different radii, and decide on the importance of the MRI (and MHD more generally) on the evolution of these discs.

  15. What Sets the Radial Locations of Warm Debris Disks?

    Energy Technology Data Exchange (ETDEWEB)

    Ballering, Nicholas P.; Rieke, George H.; Su, Kate Y. L.; Gáspár, András, E-mail: ballerin@email.arizona.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2017-08-20

    The architectures of debris disks encode the history of planet formation in these systems. Studies of debris disks via their spectral energy distributions (SEDs) have found infrared excesses arising from cold dust, warm dust, or a combination of the two. The cold outer belts of many systems have been imaged, facilitating their study in great detail. Far less is known about the warm components, including the origin of the dust. The regularity of the disk temperatures indicates an underlying structure that may be linked to the water snow line. If the dust is generated from collisions in an exo-asteroid belt, the dust will likely trace the location of the water snow line in the primordial protoplanetary disk where planetesimal growth was enhanced. If instead the warm dust arises from the inward transport from a reservoir of icy material farther out in the system, the dust location is expected to be set by the current snow line. We analyze the SEDs of a large sample of debris disks with warm components. We find that warm components in single-component systems (those without detectable cold components) follow the primordial snow line rather than the current snow line, so they likely arise from exo-asteroid belts. While the locations of many warm components in two-component systems are also consistent with the primordial snow line, there is more diversity among these systems, suggesting additional effects play a role.

  16. The role of bank erosion on the initiation and motion of gully debris flows

    Science.gov (United States)

    Lyu, Liqun; Wang, Zhaoyin; Cui, Peng; Xu, Mengzhen

    2017-05-01

    The erosion of sediment through the exchange of momentum and energy transfer within the debris flow affects the unstable motion of the debris flow. Many models have been established to study the impact of erosion on debris flow motion, but most of the models were based on bed erosion. This paper analyzed the process of unstable motion of debris flows through an experimental flume to contrast bank erosion-dominated conditions and bed erosion-only conditions. The experiments showed that bank erosion enhanced the formation and propagation of debris flows. The volume of sediments eroded by water and the debris flow mass for the bank erosion-dominated conditions was much greater than that for the bed erosion-only conditions. The height and velocity of the debris flows fluctuated, and the total basal normal stress and pore pressure increased unsteadily along the path under both conditions. However, bank erosion increased the velocity of the debris flow and made the motion fluctuation more obvious. Physical equations were established and the analyses suggested that bank erosion-dominated debris flows had increased resistance and gradient enhancement than that of bed erosion-only debris flows.

  17. Unravelling the evolution and avulsion mechanisms of debris-flow fans

    Science.gov (United States)

    de Haas, Tjalling; Densmore, Alex; Stoffel, Markus; Ballesteros-Cánovas, Juan; Suwa, Hiroshi; Imaizumi, Fumitoshi; Wasklewicz, Thad

    2017-04-01

    Debris flows are water-laden masses of soil and fragmented rock that rush down mountainsides and spill out onto valley floors and alluvial fans, where they can devastate people and property. Expansion of human population into mountainous regions and the effects of global warming have increased the hazardous effects of debris flows over the last decades. Debris-flow channel avulsions (channel shifts) are critical to debris-flow fan evolution and hazard mitigation, because avulsions distribute debris flows and associated hazards through space and time. However, both the long-term evolution of debris-flow fans and their avulsion process are poorly understood. We aim to unravel the spatio-temporal patterns of debris-flow fan evolution and their avulsion mechanisms and tendency. Here we present a combined analysis of laboratory experiments; field data (repeat topographic analyses and dendrogeomorphological and lichenometrical reconstructions from debris-flow fans in Japan, USA, Switserland and France) and numerical modelling, identifying the main drivers of avulsion on debris-flow fans and their associated spatio-temporal evolution. We show that there are two main processes driving avulsions on debris-flow fans operating at two distinct timescales. (1) Channel plugs locally block channels forcing subsequent flows to avulse and follow alternative flow paths. The frequent but stochastic nature of channel-plug formation leads to a partly unpredictable avulsion and spatial depositional patterns on timescales of a few events. (2) Nevertheless, over timescales of tens of events the average locus of debris-flow deposition is observed to gradually shift towards the topographically lower parts of a fan, highlighting the importance of topographic compensation in the avulsion process on debris-flow fans. We further show that the magnitude-frequency distribution of the debris flows feeding a fan strongly affects the spatio-temporal patterns of deposition. Our results have strong

  18. Experiments and simulation of a net closing mechanism for tether-net capture of space debris

    Science.gov (United States)

    Sharf, Inna; Thomsen, Benjamin; Botta, Eleonora M.; Misra, Arun K.

    2017-10-01

    This research addresses the design and testing of a debris containment system for use in a tether-net approach to space debris removal. The tether-net active debris removal involves the ejection of a net from a spacecraft by applying impulses to masses on the net, subsequent expansion of the net, the envelopment and capture of the debris target, and the de-orbiting of the debris via a tether to the chaser spacecraft. To ensure a debris removal mission's success, it is important that the debris be successfully captured and then, secured within the net. To this end, we present a concept for a net closing mechanism, which we believe will permit consistently successful debris capture via a simple and unobtrusive design. This net closing system functions by extending the main tether connecting the chaser spacecraft and the net vertex to the perimeter and around the perimeter of the net, allowing the tether to actuate closure of the net in a manner similar to a cinch cord. A particular embodiment of the design in a laboratory test-bed is described: the test-bed itself is comprised of a scaled-down tether-net, a supporting frame and a mock-up debris. Experiments conducted with the facility demonstrate the practicality of the net closing system. A model of the net closure concept has been integrated into the previously developed dynamics simulator of the chaser/tether-net/debris system. Simulations under tether tensioning conditions demonstrate the effectiveness of the closure concept for debris containment, in the gravity-free environment of space, for a realistic debris target. The on-ground experimental test-bed is also used to showcase its utility for validating the dynamics simulation of the net deployment, and a full-scale automated setup would make possible a range of validation studies of other aspects of a tether-net debris capture mission.

  19. 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.

  20. Assessment of debris inputs from land into the river in the Three Gorges Reservoir Area, China.

    Science.gov (United States)

    Wan, Jing; Wang, Yonggui; Cheng, Meiling; Engel, Bernard A; Zhang, Wanshun; Peng, Hong

    2018-02-01

    Riverine debris in the Three Gorges Reservoir Area (TGRA) poses a threat to electricity generation, ship navigation, and water environment. Quantifying riverine debris inputs from land into the river is a foundation for modeling of the transport and accumulation of floating debris on the water surface in the TGRA. However, this has not been researched to date. In this study, debris inputs from land into the river in the TGRA were assessed according to the response relationship between debris inputs and surface runoff. The land-based debris inputs in the TGRA were estimated using simulated surface runoff which was simulated by the Soil and Water Assessment Tool (SWAT) model. Results showed that 15.32 × 10 6  kg of land-based debris was inputted into the main channel of the TGRA in 2015 which accounted for 9.74% of total debris inputs (the monitoring data of river-sourced and land-sourced debris inputs was 157.27 × 10 6  kg). Debris inputs varied seasonally and peaked in the summer season (July to September). Compared with monthly measured data, the average relative errors in 2015 were below 30%. In addition, areas with higher debris pollution inputs were mainly located in the upper section of the TGRA, between the Tang River Basin and the Long River Basin. The proposed method was tested and determined to be reliable; thus, it can be used to quickly estimate debris inputs from land into the river by surface runoff of the outlets in a river basin. Moreover, this method provides new insight into the estimation of land-based debris inputs into rivers.

  1. Bedrock erosion by sliding wear in channelized granular flow

    Science.gov (United States)

    Hung, C. Y.; Stark, C. P.; Capart, H.; Smith, B.; Maia, H. T.; Li, L.; Reitz, M. D.

    2014-12-01

    Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Bedrock wear can be separated into impact and sliding wear processes. Here we focus on sliding wear. We have conducted experiments with a 40-cm-diameter grainflow-generating rotating drum designed to simulate dry channelized debris flows. To generate sliding erosion, we placed a 20-cm-diameter bedrock plate axially on the back wall of the drum. The rotating drum was half filled with 2.3-mm-diameter grains, which formed a thin grain-avalanching layer with peak flow speed and depth close to the drum axis. The whole experimental apparatus was placed on a 100g-ton geotechnical centrifuge and, in order to scale up the stress level, spun to a range of effective gravity levels. Rates and patterns of erosion of the bedrock plate were mapped after each experiment using 3d micro-photogrammetry. High-speed video and particle tracking were employed to measure granular flow dynamics. The resulting data for granular velocities and flow geometry were used to estimate impulse exchanges and forces on the bedrock plate. To address some of the complexities of granular flow under variable gravity levels, we developed a continuum model framed around a GDR MiDi rheology. This model allowed us to scale up boundary forcing while maintaining the same granular flow regime, and helped us to understand important aspects of the flow dynamics including e.g. fluxes of momentum and kinetic energy. In order to understand the detailed processes of boundary forcing, we performed numerical simulations with a new contact dynamics model. This model confirmed key aspects of our continuum model and provided information on second-order behavior such as fluctuations in the forces acting on the wall. By combining these measurements and theoretical analyses, we have developed and calibrated a constitutive model for sliding wear that is a threshold function of

  2. Activities of JAXA's Innovative Technology Center on Space Debris Observation

    Science.gov (United States)

    Yanagisawa, T.; Kurosaki, H.; Nakajima, A.

    The innovative technology research center of JAXA is developing observational technologies for GEO objects in order to cope with the space debris problem. The center had constructed the optical observational facility for space debris at Mt. Nyukasa, Nagano in 2006. As observational equipments such as CCD cameras and telescopes were set up, the normal observation started. In this paper, the detail of the facilities and its activities are introduced. The observational facility contains two telescopes and two CCD cameras. The apertures of the telescopes are 35cm and 25 cm, respectively. One CCD camera in which 2K2K chip is installed can observe a sky region of 1.3 times 1.3-degree using the 35cm telescope. The other CCD camera that contains two 4K2K chips has an ability to observe 2.6 times 2.6-degree's region with the 25cm telescope. One of our main objectives is to detect faint GEO objects that are not catalogued. Generally, the detection limit of GEO object is determined by the aperture of the telescope. However, by improving image processing techniques, the limit may become low. We are developing some image processing methods that use many CCD frames to detect faint objects. We are trying to use FPGA (Field Programmable Gate Array) system to reduce analyzing time. By applying these methods to the data taken by a large telescope, the detection limit will be significantly lowered. The orbital determination of detected GEO debris is one of the important things to do. Especially, the narrow field view of an optical telescope hinders us from re-detection of the GEO debris for the orbital determination. Long observation time is required for one GEO object for the orbital determination that is inefficient. An effective observation strategy should be considered. We are testing one observation method invented by Umehara that observes one inertia position in the space. By observing one inertia position for two nights, a GEO object that passed through the position in the

  3. Toward an operational use of debris-flow monitoring stations

    Science.gov (United States)

    Fontaine, Firmin; Bel, Coraline; Bellot, Hervé; Liébault, Frédéric

    2017-04-01

    The detection and the characterization of both debris flows and their occurrence conditions using monitoring stations was increasingly developed during the last two decades. The devices operate with various types of sensors and techniques, and in particular rain gauge, ground vibration sensors, flow stage sensors or video cameras. In case of debris-flow detection, such sensors make it possible to estimate the peak flow depth, the mean flow velocity, the flow discharge and the transported volume. These flow characteristics as well as the occurrence frequency are quantitative information relevant for hazard assessment. The multiplication of instrumented debris-flow prone sites could improve the evaluation of regional influences which affect, for instance, the occurrence conditions used in regional early-warning system. However, because debris-flow monitoring stations have to operate in harsh conditions and require both, strong maintenance and time-consuming post-processing, their use in operational context is still limited. A key element of the post-processing relies on the seismic signal from geophones. Indeed, such a signal is used for the recognition of the flow process involved and for estimating the surge velocity. Because very high frequency recording is not suitable for such monitoring stations, the seismic signal has to be conditioned while maintaining flow signature. We developed an electronic interface for analogically processing the raw signal, similarly to the so-called amplitude method: it allows us to preserve the signal energy while degrading the temporal resolution. For dealing with the continuum of sediment processes, from bedload transport to debris flow, but also with the sensor sensitivity to vibration source distance, the system has been adapted. A better characterization of the sediment transport process is expected. It should improve the automatic classification of rainfall events responsible for large, small and no flow occurrence. Finally

  4. Space Debris Removal from the Near-Earth Space

    Directory of Open Access Journals (Sweden)

    V. V. Zelentsov

    2016-01-01

    Full Text Available The article deals with issues related to the removal of man-made space debris (SD from the near-Earth space. SD is divided into observed (a typical size of over 100 mm and unobserved ones. When encountering the observed SD, a spacecraft takes evasive maneuvers by changing the height. The International Space orbital station used to commit this maneuver more than once. Panels protect a spacecraft from unobserved debris. SD has emerged from the former used satellites, vehicle stages, and boosters still available on orbit, as well as a result of their destruction in case of explosion and collision. A large number of projects on removal of the near-Earth space from both the observed and the unobserved fragments of SD have been recently under development. There are offerings to remove SD via grapple fixtures, mesh-works, harpoons, etc. All anti-debris means are placed in the spacecraft (SC and boosted into an orbit, and vehicle stages and boosters still remain on the orbit. Russia has set a Standard, which specifies the SD counter-measures. It gives recommendation for choosing the way of its disposal and dimensioning the fuel mass required for disposal in the dumping area. Selection of the dumping area depends on the altitude of a SD fragment. For high orbits the dumping area is selected according to GOST formulas. From the low orbits the fragments should be taken away to the Earth's atmosphere where they should be burned up. The calculations presented in the article show that with dumping area chosen properly the fuel mass required for maneuver is 10 - 15%. However, given the high cost of the spacecraft and its launch into orbit it is advisable to use the shuttle type vehicles similar to "Buran" and "Space Shuttle" to retrieve the spacecraft from the orbit. Space Shuttles were used to do similar work. This will allow preventing from near-Earth’s space debris due to available final vehicle stages and boosters, and, what is most important, after

  5. Effect of excess pore pressure on the long runout of debris flows over low gradient channels: A case study of the Dongyuege debris flow in Nu River, China

    Science.gov (United States)

    Zhou, Zhen-Hua; Ren, Zhe; Wang, Kun; Yang, Kui; Tang, Yong-Jun; Tian, Lin; Xu, Ze-Min

    2018-05-01

    Debris flows with long reaches are one of the major natural hazards to human life and property on alluvial fans, as shown by the debris flow that occurred in the Dongyuege (DYG) Gully in August 18, 2010, and caused 96 deaths. The travel distance and the runout distance of the DYG large-scale tragic debris flow were 11 km and 9 km, respectively. In particular, the runout distance over the low gradient channel (channel slope value (Kp) and rate of dissipation (R) of relative excess pore pressure are dependent on SVC. Further, the SVC that gives the lowest rate of dissipation is regarded as the optimum SVC (Cvo). The dissipation response of excess pore pressure can be characterized by the R value under Cvo at a given moment (i.e., 0.5 h, 1 h or 2 h later after peak time). The results reveal that a relatively high level of excess pore pressure developed within the DYG debris-flow mass and had a strong persistence capability. Further research shows that the development, peak value and dissipation of excess pore pressure in a mixture of sediment and water are related to the maximum grain size (MGS), gradation and mineralogy of clay-size particles of the sediment. The layer-lattice silicates in clay particles can be the typical clay minerals, including kaolinite, montmorillonite and illite, and also the unrepresentative clay minerals such as muscovite and chlorite. Moreover, small woody debris can also contribute to the slurrying of sediments and maintenance of debris flows in well vegetated mountainous areas and the boulders suspended in debris flows can elevate excess pore pressure and extend debris-flow mobility. The parameters, including Id, Kp, R and etc., are affected by the intrinsic properties of debris. They, therefore, can reflect the slurrying susceptibility of sediments, and can also be applied to the research on the occurrence mechanisms and risk assessment of other debris flows.

  6. Model microswimmers in channels with varying cross section

    Science.gov (United States)

    Malgaretti, Paolo; Stark, Holger

    2017-05-01

    We study different types of microswimmers moving in channels with varying cross section and thereby interacting hydrodynamically with the channel walls. Starting from the Smoluchowski equation for a dilute suspension, for which interactions among swimmers can be neglected, we derive analytic expressions for the lateral probability distribution between plane channel walls. For weakly corrugated channels, we extend the Fick-Jacobs approach to microswimmers and thereby derive an effective equation for the probability distribution along the channel axis. Two regimes arise dominated either by entropic forces due to the geometrical confinement or by the active motion. In particular, our results show that the accumulation of microswimmers at channel walls is sensitive to both the underlying swimming mechanism and the geometry of the channels. Finally, for asymmetric channel corrugation, our model predicts a rectification of microswimmers along the channel, the strength and direction of which strongly depends on the swimmer type.

  7. Efficacy of hydrogen peroxide for treating saprolegniasis in channel catfish

    Science.gov (United States)

    Howe, G.E.; Gingerich, W.H.; Dawson, V.K.; Olson, J.J.

    1999-01-01

    Hatchery-reared fish and their eggs are commonly afflicted with saprolegniasis, a fungal disease that can cause significant losses in production. Fish culturists need safe and effective fungicides to minimize losses and meet production demands. The efficacy of hydrogen peroxide was evaluated for preventing or controlling mortality associated with saprolegniasis in channel catfish Ictalurus punctatus. Saprolegniasis was systematically induced in channel catfish so various therapies could be evaluated in a controlled laboratory environment. Both prophylactic and therapeutic hydrogen peroxide bath treatments of 50, 100, and 150 ??L/L for 1 h were administered every other day for seven total treatments. All untreated positive control fish died of saprolegniasis during the prophylactic and therapeutic tests. Hydrogen peroxide treatments of 150 ??L/L were harmful (relative to lower concentrations) to test fish and resulted in 73-95% mortality. Mortality was attributed to a combination of abrasion, temperature, chemical treatment, and disease stressors. Treatments of 100 ??L/L were less harmful (relatively) but also appeared to contribute to mortality (60-79%). These treatments, however, significantly reduced the incidence of mortality and infection compared with those observed for fish of the positive control or 150-??L/L treatment groups. Overall, treatments of 50 ??L/L were found to be the most safe and effective of those tested. Mortality with this concentration ranged from 16% in therapeutic tests to 41% in prophylactic tests. The statistical model employed estimated that the optimum treatment concentration for preventing or controlling mortality, reducing the incidence of infections, and enhancing the recovery of infected fish was 75 ??L H2O2/L.

  8. An enhanced temperature index model for debris-covered glaciers accounting for thickness effect

    Science.gov (United States)

    Carenzo, M.; Pellicciotti, F.; Mabillard, J.; Reid, T.; Brock, B. W.

    2016-08-01

    Debris-covered glaciers are increasingly studied because it is assumed that debris cover extent and thickness could increase in a warming climate, with more regular rockfalls from the surrounding slopes and more englacial melt-out material. Debris energy-balance models have been developed to account for the melt rate enhancement/reduction due to a thin/thick debris layer, respectively. However, such models require a large amount of input data that are not often available, especially in remote mountain areas such as the Himalaya, and can be difficult to extrapolate. Due to their lower data requirements, empirical models have been used extensively in clean glacier melt modelling. For debris-covered glaciers, however, they generally simplify the debris effect by using a single melt-reduction factor which does not account for the influence of varying debris thickness on melt and prescribe a constant reduction for the entire melt across a glacier. In this paper, we present a new temperature-index model that accounts for debris thickness in the computation of melt rates at the debris-ice interface. The model empirical parameters are optimized at the point scale for varying debris thicknesses against melt rates simulated by a physically-based debris energy balance model. The latter is validated against ablation stake readings and surface temperature measurements. Each parameter is then related to a plausible set of debris thickness values to provide a general and transferable parameterization. We develop the model on Miage Glacier, Italy, and then test its transferability on Haut Glacier d'Arolla, Switzerland. The performance of the new debris temperature-index (DETI) model in simulating the glacier melt rate at the point scale is comparable to the one of the physically based approach, and the definition of model parameters as a function of debris thickness allows the simulation of the nonlinear relationship of melt rate to debris thickness, summarised by the

  9. Quantities of arsenic-treated wood in demolition debris generated by Hurricane Katrina.

    Science.gov (United States)

    Dubey, Brajesh; Solo-Gabriele, Helena M; Townsendt, Timothy G

    2007-03-01

    The disaster debris from Hurricane Katrina is one of the largest in terms of volume and economic loss in American history. One of the major components of the demolition debris is wood waste of which a significant proportion is treated with preservatives, including preservatives containing arsenic. As a result of the large scale destruction of treated wood structures such as electrical poles, fences, decks, and homes a considerable amount of treated wood and consequently arsenic will be disposed as disaster debris. In this study an effort was made to estimate the quantity of arsenic disposed through demolition debris generated in the Louisiana and Mississippi area through Hurricane Katrina. Of the 72 million cubic meters of disaster debris generated, roughly 12 million cubic meters were in the form of construction and demolition wood resulting in an estimated 1740 metric tons of arsenic disposed. Management of disaster debris should consider the relatively large quantities of arsenic associated with pressure-treated wood.

  10. Assessment of floating plastic debris in surface water along the Seine River.

    Science.gov (United States)

    Gasperi, Johnny; Dris, Rachid; Bonin, Tiffany; Rocher, Vincent; Tassin, Bruno

    2014-12-01

    This study is intended to examine the quality and quantity of floating plastic debris in the River Seine through use of an extensive regional network of floating debris-retention booms; it is one of the first attempts to provide reliable information on such debris at a large regional scale. Plastic debris represented between 0.8% and 5.1% of total debris collected by weight. A significant proportion consisted of food wrappers/containers and plastic cutlery, probably originating from voluntary or involuntary dumping, urban discharges and surface runoff. Most plastic items are made of polypropylene, polyethylene and, to a lesser extent, polyethylene terephthalate. By extrapolation, some 27 tons of floating plastic debris are intercepted annually by this network; corresponding to 2.3 g per Parisian inhabitant per year. Such data could serve to provide a first evaluation of floating plastic inputs conveyed by rivers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Fisheries as a source of marine debris on beaches in the United Kingdom.

    Science.gov (United States)

    Unger, Antonia; Harrison, Nancy

    2016-06-15

    Marine debris from ships has persisted and remains a concern despite international agreements such as MARPOL. We report on an analysis of beach litter based on a data set established by the Marine Conservation Society (MSC) Beachwatch weekends. Debris collected around the UK was divided into three main types of debris: (1) plastic, (2) fishing, and (3) fishing related plastic and rubber. Correspondence analysis (CA) was used to examine patterns in the occurrence of debris types on a total of 1023 beaches and debris attributable to fishing was identified on clusters of beaches mainly located on the coasts of Scotland and along the English Channel. General Linear model (GLM) identified fishing as the highest explanatory factor when testing for relationships between litter and proximity to fishing ports and grounds. The results add to the growing body of evidence that the fishing industry is largely responsible for marine debris. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  12. Prevalence and composition of marine debris in Brown Booby (Sula leucogaster) nests at Ashmore Reef.

    Science.gov (United States)

    Lavers, Jennifer L; Hodgson, Jarrod C; Clarke, Rohan H

    2013-12-15

    Anthropogenic debris is ubiquitous in the marine environment and has been reported to negatively impact hundreds of species globally. Seabirds are particularly at risk from entanglement in debris due to their habit of collecting food and, in many cases, nesting material off the ocean's surface. We compared the prevalence and composition of debris in nests and along the beach at two Brown Booby (Sula leucogaster) colonies on Ashmore Reef, Timor Sea, a remote area known to contain high densities of debris transported by ocean currents. The proportion of nests with debris varied across islands (range 3-31%), likely in response to the availability of natural nesting materials. Boobies exhibited a preference for debris colour (white and black), but not type. The ephemeral nature of Brown Booby nests on Ashmore Reef may limit their utility as indicators of marine pollution, however monitoring is recommended in light of increasing demand for plastic products. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Practical engineering approaches and infrastructure to address the problem of marine debris in Korea.

    Science.gov (United States)

    Jung, Rho-Taek; Sung, Hong Gun; Chun, Tae-Byong; Keel, Sang-In

    2010-09-01

    As a solution to the problem of persistent solid marine debris, a nationwide project began in Korea in 1999 to develop and popularize fundamental changes to the infrastructure. The ten year project, called "A Practical Integrated System for Marine Debris," consists of four linked types of technology: prevention, deep-water survey, removal and treatment (recycling). These reflect the characteristics of marine debris, which though widespread, vary by location and time of generation. Each technical component has each representative outcome that has been outreached the local governments and marine debris-related associations. The in situ infrastructures lead to enhance the retrieval of the marine debris and create direct and indirect benefits to industry. Both end-of-pipe technology improvement and the introduction of front-of-pipe technology should be considered as we strive to reduce the generation of marine debris in Korean coastal areas. Copyright 2010 Elsevier Ltd. All rights reserved.

  14. Impacts of marine debris on wild animals in the coastal area of Korea.

    Science.gov (United States)

    Hong, Sunwook; Lee, Jongmyoung; Jang, Yong Chang; Kim, Young Jun; Kim, Hee Jong; Han, Donguk; Hong, Sang Hee; Kang, Daeseok; Shim, Won Joon

    2013-01-15

    Over the last decade, marine debris has become a major factor affecting the coastal ecosystem of Korea. This study compiled information regarding how marine debris impacts wildlife in Korea. Cases of marine debris impacting wildlife were collected from experts of various fields and from local participants through an open access website from February 2010 to March 2012. A total of 21 species were affected by marine debris: 18 species of birds, 2 species of mammals, and 1 species of crustacean. Five threatened or protected species were identified: black-faced spoonbill, finless porpoise, water deer, whooper swan, and greater painted snipe. Recreational fishing gears were the types of debris that most frequently impacted wildlife, especially birds. Black tailed gulls were the most vulnerable species to recreational fishing hooks and lines. Although it was preliminary, this study revealed that recreational fishing activities should be prioritized when managing marine debris in Korea. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Temporal variability of marine debris deposition at Tern Island in the Northwestern Hawaiian Islands.

    Science.gov (United States)

    Agustin, Alyssa E; Merrifield, Mark A; Potemra, James T; Morishige, Carey

    2015-12-15

    A twenty-two year record of marine debris collected on Tern Island is used to characterize the temporal variability of debris deposition at a coral atoll in the Northwestern Hawaiian Islands. Debris deposition tends to be episodic, without a significant relationship to local forcing processes associated with winds, sea level, waves, and proximity to the Subtropical Convergence Zone. The General NOAA Operational Modeling Environment is used to estimate likely debris pathways for Tern Island. The majority of modeled arrivals come from the northeast following prevailing trade winds and surface currents, with trajectories indicating the importance of the convergence zone, or garbage patch, in the North Pacific High region. Although debris deposition does not generally exhibit a significant seasonal cycle, some debris types contain considerable 3 cycle/yr variability that is coherent with wind and surface pressure over a broad region north of Tern. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Space Debris Detection in Low Earth Orbit with the Sardinia Radio Telescope

    Directory of Open Access Journals (Sweden)

    Giacomo Muntoni

    2017-08-01

    Full Text Available Space debris are orbiting objects that represent a major threat for space operations. The most used countermeasure to face this threat is, by far, collision avoidance, namely the set of maneuvers that allow to avoid a collision with the space debris. Since collision avoidance is tightly related to the knowledge of the debris state (position and speed, the observation of the orbital debris is the key of the problem. In this work a bistatic radar configuration named BIRALET (BIstatic RAdar for LEO Tracking is used to detect a set of space debris at 410 MHz, using the Sardinia Radio Telescope as the receiver antenna. The signal-to-noise ratio, the Doppler shift and the frequency spectrum for each debris are reported.

  17. First evidence of tyre debris characterization at the nanoscale by focused ion beam

    International Nuclear Information System (INIS)

    Milani, M.; Pucillo, F.P.; Ballerini, M.; Camatini, M.; Gualtieri, M.; Martino, S.

    2004-01-01

    In this paper, we present a novel technique for the nanoscale characterization of the outer and inner structure of tyre debris. Tyre debris is produced by the normal wear of tyres. In previous studies, the microcharacterization and identification were performed by analytical electron microscopy. This study is a development of the characterization of surface and microstructure of tyre debris. For the first time, tyre debris was analysed by focused ion beam (FIB), a technique with 2- to 5-nm resolution that does not require any sample preparation. We studied tyre debris produced in the laboratory. We made electron and ionic imaging of the surface of the material, and after a ionic cut, we studied the internal microstructure of the same sample. The tyre debris was analysed by FIB without any sample preparations unlike the case of scanning and transmission electron microscopy (SEM and TEM). Useful information was derived to improve detection and monitoring techniques of pollution by tyre degradation processes

  18. Coastal debris survey in a Remote Island of the Chilean Northern Patagonia.

    Science.gov (United States)

    Perez-Venegas, D; Pavés, H; Pulgar, J; Ahrendt, C; Seguel, M; Galbán-Malagón, C J

    2017-12-15

    Global marine litter pollution is increasing dramatically, and oceanic islands are one of the most vulnerable ecosystems due to their high debris accumulation rate compared to continental sites. Remote areas, such as inhabited islands, represent a perfect study case to track marine debris sources, due to the assumed low rates of local production of debris. Guafo Island is one of the largest islands of the Chilean Northern Patagonia and is considered a remote zone. The accessible coast of Guafo Island was monitored during four austral summers revealing higher levels of marine debris accumulation than continental Chile. Plastic was the most abundant type of debris constituting 50% of the total litter monitored. Our results suggest that most of the plastic identified is likely to be related to local fisheries activities. Mitigation measures including collaboration among fishing communities and scientists could contribute to reduce the coastal debris pollution in remote areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Rocky shoreline protocols miss microplastics in marine debris surveys (Fogo Island, Newfoundland and Labrador).

    Science.gov (United States)

    McWilliams, Matt; Liboiron, Max; Wiersma, Yolanda

    2017-10-12

    Most anthropogenic marine debris shoreline studies are conducted on sandy shores, rather than rocky coastlines. We amended a standardized protocol for monitoring marine debris on a high-loading beach composed of small rocks and cobbles in Newfoundland, Canada. Our protocol had two parts: we conducted stratified sampling to a depth of ~20cm below the surface of the rocks (standing survey), and surveyed accumulation of items on the surface of rocks every other day (loading survey). We found the vast majority of smaller items were below the surface. Only 17.2% of debris were microplastics (<5mm). Types of anthropogenic debris differed significantly between the standing survey and the loading survey. We found no relationship between either wind direction or wind speed, and distributions of debris. This study allows for a better understanding of marine debris detection along rocky coasts, and the limitations of protocols for studying them. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Occurrence of Plastic Micro-Debris in the California Current System

    OpenAIRE

    Gilfillan, Lisa

    2009-01-01

    We analyzed the spatial distribution, concentration, and characteristics of plastic micro-debris in neuston samples from the CalCOFI region off the Southern California Coast from winter cruises in 1984, 1994, and 2007. By sorting archived CalCOFI zooplankton samples, we were able to separate micro-debris particles and characterize particle size, circularity, and surface area using digital image analysis by ZooScan. Our results suggest that plastic micro-debris is widespread in the California ...

  1. Relationship of Course Woody Debris to Red-Cockaded Woodpecker Prey Diversity and Abundance

    Energy Technology Data Exchange (ETDEWEB)

    Horn, G.S.

    1999-09-03

    The abundance of diversity of prey commonly used by the red-cockaded woodpecker were monitored in experimental plots in which course woody debris was manipulated. In one treatment, all the woody debris over four inches was removed. In the second treatment, the natural amount of mortality remained intact. The overall diversity of prey was unaffected; however, wood roaches were significantly reduced by removal of woody debris. The latter suggests that intensive utilizations or harvesting practices may reduce foraging.

  2. Dynamics of Flexible MLI-type Debris for Accurate Orbit Prediction

    Science.gov (United States)

    2014-09-01

    that this type of debris is made of multi-layer insulation, but there is no evidence to confirm so. Further experiments were conducted by Murakami et...mass distribution. Some evidence supports that the mass distribution concerning material in the experiments of the study of Murakami [17] and support...61 4.2. Average solar radiation pressure for rigid debris The attitude of a piece of debris will alter the effects of solar radiation

  3. Plastic debris ingestion by sea turtle in Paraíba, Brazil.

    Science.gov (United States)

    Mascarenhas, Rita; Santos, Robson; Zeppelini, Douglas

    2004-08-01

    Coastal gill net entanglement and debris intake are important threats to the survival of sea turtles. Two sea turtles (Lepidochelys olivacea and Chelonia mydas) were found stranded along the coast of Paraíba. After necropsy, plastic debris were found in the stomach. The debris is described. This is the first record of this sort of problem for the Paraíba littoral.

  4. Phase shifting-based debris effect detection in USV-assisted AFM nanomachining

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jialin [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences (CAS), Shenyang, Liaoning 110016 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Beijing Advanced Innovation Center for Imaging Technology, Capital Normal University, Beijing 100049 (China); Liu, Lianqing, E-mail: lianqingliu@sia.cn [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences (CAS), Shenyang, Liaoning 110016 (China); Yu, Peng; Cong, Yang [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences (CAS), Shenyang, Liaoning 110016 (China); Li, Guangyong [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA 15213 (United States)

    2017-08-15

    Highlights: • The mechanism of the debris effect on machining depth in force control mode operation is analyzed. • The relationship between phase shifting and pile-up of debris is investigated. • The phase shifting-based method is hardly affected by the pile-up of debris. • Debris effect detection by phase shifting-based method is achived. - Abstract: Atomic force microscopy (AFM) mechanical-based lithography attracts much attention in nanomanufacturing due to its advantages of low cost, high precision and high resolution. However, debris effects during mechanical lithography often lead to an unstable machining process and inaccurate results, which limits further applications of AFM-based lithography. There is a lack of a real-time debris detection approach, which is the prerequisite to eventually eliminating the influence of the debris, and of a method that can solve the above problems well. The ultrasonic vibration (USV)-assisted AFM has the ability to sense the machining depth in real time by detecting the phase shifting of cantilever. However, whether the pile-up of debris affect the phase response of cantilever is still lack of investigation. Therefore, we analyzed the mechanism of the debris effect on force control mode and investigated the relationship between phase shifting and pile-up of debris. Theoretical analysis and experimental results reveal that the pile-up of debris have negligible effect on phase shifting of cantilever. Therefore, the phase shifting-based method can detect the debris effect on machining depth in force control mode of AFM machining.

  5. Eliminating Space Debris: Applied Technology and Policy Prescriptions, Fall 2007 - Project 07-02

    Science.gov (United States)

    2008-01-01

    debris from the country’s own Ariane I rocket body,27 “Just imagine if that debris had come from a Russian or Chinese launcher.”28 Space Debris...secondary solid fueled rockets for added lifting power. The secondary rockets , also known as motors, can be seen in Figure 7 in the lower portion of the...FRPSOLDQWHJ [[[[[[ 5(32577ɛ(6WDWHWKHW\\SHRIUHSRUWVXFKDV ILQDOWHFKQLFDOLQWHULPPHPRUDQGXPPDVWHU V

  6. Utilizing Weather RADAR for Rapid Location of Meteorite Falls and Space Debris Re-Entry

    Science.gov (United States)

    Fries, Marc D.

    2016-01-01

    This activity utilizes existing NOAA weather RADAR imagery to locate meteorite falls and space debris falls. The near-real-time availability and spatial accuracy of these data allow rapid recovery of material from both meteorite falls and space debris re-entry events. To date, at least 22 meteorite fall recoveries have benefitted from RADAR detection and fall modeling, and multiple debris re-entry events over the United States have been observed in unprecedented detail.

  7. Characterizing Longitude-Dependent Orbital Debris Congestion in the Geosynchronous Orbit Regime

    Science.gov (United States)

    Anderson, Paul V.

    The geosynchronous orbit (GEO) is a unique commodity of the satellite industry that is becoming increasingly contaminated with orbital debris, but is heavily populated with high-value assets from the civil, commercial, and defense sectors. The GEO arena is home to hundreds of communications, data transmission, and intelligence satellites collectively insured for an estimated 18.3 billion USD. As the lack of natural cleansing mechanisms at the GEO altitude renders the lifetimes of GEO debris essentially infinite, conjunction and risk assessment must be performed to safeguard operational assets from debris collisions. In this thesis, longitude-dependent debris congestion is characterized by predicting the number of near-miss events per day for every longitude slot at GEO, using custom debris propagation tools and a torus intersection metric. Near-miss events with the present-day debris population are assigned risk levels based on GEO-relative position and speed, and this risk information is used to prioritize the population for debris removal target selection. Long-term projections of debris growth under nominal launch traffic, mitigation practices, and fragmentation events are also discussed, and latitudinal synchronization of the GEO debris population is explained via node variations arising from luni-solar gravity. In addition to characterizing localized debris congestion in the GEO ring, this thesis further investigates the conjunction risk to operational satellites or debris removal systems applying low-thrust propulsion to raise orbit altitude at end-of-life to a super-synchronous disposal orbit. Conjunction risks as a function of thrust level, miss distance, longitude, and semi-major axis are evaluated, and a guidance method for evading conjuncting debris with continuous thrust by means of a thrust heading change via single-shooting is developed.

  8. The complex interaction between marine debris and toxic chemicals in the ocean.

    Science.gov (United States)

    Engler, Richard E

    2012-11-20

    Marine debris, especially plastic debris, is widely recognized as a global environmental problem. There has been substantial research on the impacts of plastic marine debris, such as entanglement and ingestion. These impacts are largely due to the physical presence of plastic debris. In recent years there has been an increasing focus on the impacts of toxic chemicals as they relate to plastic debris. Some plastic debris acts as a source of toxic chemicals: substances that were added to the plastic during manufacturing leach from plastic debris. Plastic debris also acts as a sink for toxic chemicals. Plastic sorbs persistent, bioaccumulative, and toxic substances (PBTs), such as polychlorinated biphenyls (PCBs) and dioxins, from the water or sediment. These PBTs may desorb when the plastic is ingested by any of a variety of marine species. This broad look at the current research suggests that while there is significant uncertainty and complexity in the kinetics and thermodynamics of the interaction, plastic debris appears to act as a vector transferring PBTs from the water to the food web, increasing risk throughout the marine food web, including humans. Because of the extremely long lifetime of plastic and PBTs in the ocean, prevention strategies are vital to minimizing these risks.

  9. Origin of marine debris is related to disposable packs of ultra-processed food.

    Science.gov (United States)

    Andrades, Ryan; Martins, Agnaldo S; Fardim, Lorena M; Ferreira, Juliana S; Santos, Robson G

    2016-08-15

    Marine debris is currently distributed worldwide, and the discard and contamination pose hazards to human and wildlife health. One of the gaps in debris science is tracking the source of debris to better evaluate and avoid the pathway of debris from the source to marine environment. For this, we evaluated three beaches of different urbanization levels and environmental influences; a low urbanized beach, a highly urbanized beach and a non-urbanized estuary-associated beach, in order to determine the sources and original use of debris. Plastic was the major material found on beaches, and the urbanized beach recorded the highest debris densities. Marine debris was primarily from land-based sources, and the debris recorded in all beaches was mainly assigned as food-related items. Our results highlight the major presence of disposable and short-lived products comprising the majority of debris that enters the ocean and draw attention to the unsustainable lifestyle of current society. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. The influx of marine debris from the Great Japan Tsunami of 2011 to North American shorelines.

    Science.gov (United States)

    Murray, Cathryn Clarke; Maximenko, Nikolai; Lippiatt, Sherry

    2018-01-10

    Marine debris is one of the leading threats to the ocean and the Great East Japan Earthquake and tsunami on March 11, 2011 washed away an estimated 5million tons of debris in a single, tragic event. Here we used shoreline surveys, disaster debris reports and ocean drift models to investigate the temporal and spatial trends in the arrival of tsunami marine debris. The increase in debris influx to surveyed North American and Hawaiian shorelines was substantial and significant, representing a 10 time increase over the baseline in northern Washington State where a long term dataset was available. The tsunami event brought different types of debris along the coast, with high-windage items dominant in Alaska and British Columbia and large, medium-windage items in Washington State and Oregon. Recorded cumulative debris landings to North America were close to 100,000 items in the four year study period. The temporal peaks in measured shoreline debris and debris reports match the ocean drift model solutions. Mitigation and monitoring activities, such as shoreline surveys, provide crucial data and monitoring for potential impacts should be continued in the future. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

  11. Dynamics and control for contactless interaction between spacecraft and tumbling debris

    Science.gov (United States)

    Li, Haiyang; Li, Jingyang; Jiang, Fanghua

    2018-01-01

    Tumbling debris has become a great threat to orbit activities. Contactless interaction is a novel concept for active debris removal, through which the tumbling debris no longer rotates freely but is under control. The contactless interaction method aims to de-tumble the debris and then maintain desired relative states between the spacecraft and debris. The spacecraft is simultaneously stabilized through three-axis attitude control, which makes the de-tumbling and capture operation much safer, more effective and accurate. The dynamics and control for the contactless interaction have been little studied in the past years. This paper considers a generic dynamics and control problem for contactless interaction between a spacecraft and debris. A translational and rotational dynamics model of contactless interaction is proposed and the 6-DOF equations are established. The contactless interaction control law is designed with the backstepping method, and the spacecraft three-axis control law is designed with the PD control. Simulation results show that the angular momentum is transferred from the debris to the spacecraft and the debris is thus de-tumbled. The desired relative states are achieved efficiently. Significantly, the spacecraft and debris no longer rotate in the inertial frame and, hence, the safety and accuracy for capture operation are guaranteed.

  12. TMI-2 core debris-cesium release/settling test. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Akers, D W; Johnson, D A

    1984-12-01

    Cesium release, turbidity and airborne potential tests were conducted on 50 grams of TMI-2 core debris materials. The tests were performed on the debris in two conditions: on the as-received core debris specimen, and after crushing the debris to alter the particle size distribution. The crushing was intended to simulate the breakup of TMI-2 core material that may occur during reactor defueling. These tests are intended to assist GPU Nuclear in predicting the effect of defueling on the reactor environment.

  13. Cost and risk assessment for spacecraft operation decisions caused by the space debris environment

    Science.gov (United States)

    Schaub, Hanspeter; Jasper, Lee E. Z.; Anderson, Paul V.; McKnight, Darren S.

    2015-08-01

    Space debris is a topic of concern among many in the space community. Most forecasting analyses look centuries into the future to attempt to predict how severe debris densities and fluxes will become in orbit regimes of interest. Conversely, space operators currently do not treat space debris as a major mission hazard. This survey paper outlines the range of cost and risk evaluations a space operator must consider when determining a debris-related response. Beyond the typical direct costs of performing an avoidance maneuver, the total cost including indirect costs, political costs and space environmental costs are discussed. The weights on these costs can vary drastically across mission types and orbit regimes flown. The operator response options during a mission are grouped into four categories: no action, perform debris dodging, follow stricter mitigation, and employ ADR. Current space operations are only considering the no action and debris dodging options, but increasing debris risk will eventually force the stricter mitigation and ADR options. Debris response equilibria where debris-related risks and costs settle on a steady-state solution are hypothesized.

  14. Attitude Motion of Cylindrical Space Debris during Its Removal by Ion Beam

    Directory of Open Access Journals (Sweden)

    Vladimir S. Aslanov

    2017-01-01

    Full Text Available The paper is devoted to the problem of space debris mitigation. Contactless method of the space debris deorbiting is considered. It is assumed that ion thrusters on the active spacecraft create the ion flow, which blows the debris and slows it down. The objectives of this work are the development of mathematical models and the research of space debris motion under the action of the ion flow. It is supposed that the space debris is a rigid body of a cylindrical shape. Calculation of ion beam force and torque was performed for a self-similar model of plasma plume expansion using the hypothesis of ion fully diffused reflection from a surface. A mathematical model describing plane motions of the cylindrical space debris under the influence of gravity gradient torque and the ion flux was constructed. It was shown that motion of the space debris around its center of mass has a significant effect on its removal time. Phase portraits, describing the motion of the space debris relative to its center of mass, were constructed. Comparison of the descent times in different motion modes was carried out. The results can be used to create new effective systems of large space debris removal.

  15. Plastic debris in the Mediterranean Sea: Types, occurrence and distribution along Adriatic shorelines.

    Science.gov (United States)

    Munari, Cristina; Scoponi, Marco; Mistri, Michele

    2017-09-01

    Small plastic debris in sediments from five beaches were investigated to evaluate their occurrence and abundance in the Northern Adriatic coast for the first time. Plastic debris extracted from sediments were counted, weighted and identified by Fourier-transform infrared spectroscopy (FT-IR). A total of 1345 items of debris (13.491g) were recorded, with a mean density of 12.1 items kg -1 d.w. and 0.12gkg -1 d.w. Fragments were the most frequent type of small plastics debris detected. In terms of abundance, microplastics (emergent and priority contaminant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Importance of Coarse Woody Debris to Avian Communities in Loblolly Pine Forests

    Energy Technology Data Exchange (ETDEWEB)

    Lohr, S.M.; Gauthreaux, S.A.; Kilgo, J.C.

    2001-06-14

    Investigates the importance of standing and down coarse woody debris to bird communities in loblolly pine forests, researchers compared breeding and nonbreeding responses of birds among two coarse woody debris removal and control treatments. Quantification of vegetation layers to determine their effects on the experimental outcome coarse woody debris removal had no effect on the nonbreeding bird community. Most breeding and nonbreeding species used habitats with sparse midstory and well-developed understory, where as sparse canopy cover and dense midstory were important to some nonbreeding species. Snag and down coarse woody debris practices that maintain a dense understory, sparse midstory and canopy will create favorable breeding habitat.

  17. Spatial and temporal patterns of stranded intertidal marine debris: is there a picture of global change?

    Science.gov (United States)

    Browne, Mark Anthony; Chapman, M Gee; Thompson, Richard C; Amaral Zettler, Linda A; Jambeck, Jenna; Mallos, Nicholas J

    2015-06-16

    Floating and stranded marine debris is widespread. Increasing sea levels and altered rainfall, solar radiation, wind speed, waves, and oceanic currents associated with climatic change are likely to transfer more debris from coastal cities into marine and coastal habitats. Marine debris causes economic and ecological impacts, but understanding the scope of these requires quantitative information on spatial patterns and trends in the amounts and types of debris at a global scale. There are very few large-scale programs to measure debris, but many peer-reviewed and published scientific studies of marine debris describe local patterns. Unfortunately, methods of defining debris, sampling, and interpreting patterns in space or time vary considerably among studies, yet if data could be synthesized across studies, a global picture of the problem may be avaliable. We analyzed 104 published scientific papers on marine debris in order to determine how to evaluate this. Although many studies were well designed to answer specific questions, definitions of what constitutes marine debris, the methods used to measure, and the scale of the scope of the studies means that no general picture can emerge from this wealth of data. These problems are detailed to guide future studies and guidelines provided to enable the collection of more comparable data to better manage this growing problem.

  18. Ice/frost/debris assessment for space shuttle Mission STS-32 (61-C)

    Science.gov (United States)

    Stevenson, Charles G.; Katnik, Gregory N.; Speece, Robert F.

    1986-01-01

    An Ice/Frost/Debris assessment was conducted for Space Shuttle Mission STS-32 (61-C). This assessment begins with debris inspections of the flight elements and launch facilities before and after launch. Ice/Frost formations are calculated during cryogenic loading of the external tank followed by an on-pad assessment of the Shuttle vehicle and pad at T-3 hours in the countdown. High speed films are reviewed after launch to identify Ice/Frost/Debris sources and investigate potential vehicle damage. The Ice/Frost/Debris conditions and their effects on the Space Shuttle are documented.

  19. Comparison of the meteorology and surface energy fluxes of debris-free and debris-covered glaciers in the southeastern Tibetan Plateau

    Science.gov (United States)

    Yang, W.

    2017-12-01

    Knowledge of the meteorology and energy fluxes of debris-free and debris-covered glaciers is important for understanding the varying response of glaciers to climate change. Field measurements at the debris-free Parlung No. 4 Glacier and the debris-covered 24K Glacier in the southeastern Tibetan Plateau were carried out to compare the meteorology and surface energy fluxes and to understand the factors controlling the melting process. The meteorological comparisons displayed temporally synchronous fluctuations in air temperature, relative humidity, incoming longwave radiation (Lin), but notable differences in precipitation, incoming shortwave radiation (Sin) and wind speed. Under the prevailing regional precipitation and debris conditions, more Lin (42 W/m2) was supplied from warmer and more humid air and more Sin (58 W/m2) was absorbed at the 24K Glacier. The relatively high energy supply led mainly to an increased energy output via turbulent heat fluxes and outgoing longwave radiation, rather than glacier melting beneath the thick debris. The sensitivity experiment showed that melting rates were sensitive to variations in energy supply with debris thicknesses of less than 10 cm. In contrast, energy supply to the ablation zone of the Parlung No. 4 Glacier mainly resulted in snow/ice melting, the magnitude of which was significantly influenced by the energy supplied by Sin and the sensible heat flux.

  20. F.I.D.O. Focused Integration for Debris Observation

    Science.gov (United States)

    Ploschnitznig, J.

    2013-09-01

    The fact that satellites play a growing role in our day-to-day live, contributes to the overall assessment that these assets must be protected. As more and more objects enter space and begin to clutter this apparently endless vacuum, we begin to realize that these objects and associated debris become a potential and recurring threat. The space surveillance community routinely attempts to catalog debris through broad area search collection profiles, hoping to detect and track smaller and smaller objects. There are technical limitations to each collection system, we propose there may be new ways to increase the detection capability, effectively "Teaching an old dog (FIDO), new tricks." Far too often, we are justly criticized for never "stepping out of the box". The philosophy of "if it's not broke, don't fix it" works great if you assume that we are not broke. The assumption that in order to "Find" new space junk we need to increase our surveillance windows and try to cover as much space as possible may be appropriate for Missile Defense, but inappropriate for finding small space debris. Currently, our Phased Array Early Warning Systems support this yearly search program to try to acquire and track space small debris. A phased array can electronically scan the horizons very quickly, but the radar does have limitations. There is a closed-loop resource management equation that must be satisfied. By increasing search volume, we effectively reduce our instantaneous sensitivity which will directly impact our ability to find smaller and smaller space debris. Our proposal will be to focus on increasing sensitivity by reducing the search volume to statistically high probability of detection volumes in space. There are two phases to this proposal, a theoretical and empirical. Theoretical: The first phase will be to investigate the current space catalog and use existing ephemeris data on all satellites in the Space Surveillance Catalog to identify volumes of space with a high

  1. The HIP 79977 debris disk in polarized light

    Science.gov (United States)

    Engler, N.; Schmid, H. M.; Thalmann, Ch.; Boccaletti, A.; Bazzon, A.; Baruffolo, A.; Beuzit, J. L.; Claudi, R.; Costille, A.; Desidera, S.; Dohlen, K.; Dominik, C.; Feldt, M.; Fusco, T.; Ginski, C.; Gisler, D.; Girard, J. H.; Gratton, R.; Henning, T.; Hubin, N.; Janson, M.; Kasper, M.; Kral, Q.; Langlois, M.; Lagadec, E.; Ménard, F.; Meyer, M. R.; Milli, J.; Mouillet, D.; Olofsson, J.; Pavlov, A.; Pragt, J.; Puget, P.; Quanz, S. P.; Roelfsema, R.; Salasnich, B.; Siebenmorgen, R.; Sissa, E.; Suarez, M.; Szulagyi, J.; Turatto, M.; Udry, S.; Wildi, F.

    2017-11-01

    Context. Debris disks are observed around 10 to 20% of FGK main-sequence stars as infrared excess emission. They are important signposts for the presence of colliding planetesimals and therefore provide important information about the evolution of planetary systems. Direct imaging of such disks reveals their geometric structure and constrains their dust-particle properties. Aims: We present observations of the known edge-on debris disk around HIP 79977 (HD 146897) taken with the ZIMPOL differential polarimeter of the SPHERE instrument. We measure the observed polarization signal and investigate the diagnostic potential of such data with model simulations. Methods: SPHERE-ZIMPOL polarimetric data of the 15 Myr-old F star HIP 79977 (Upper Sco, 123 pc) were taken in the Very Broad Band (VBB) filter (λc = 735 nm, Δλ = 290 nm) with a spatial resolution of about 25 mas. Imaging polarimetry efficiently suppresses the residual speckle noise from the AO system and provides a differential signal with relatively small systematic measuring uncertainties. We measure the polarization flux along and perpendicular to the disk spine of the highly inclined disk for projected separations between 0.2'' (25 AU) and 1.6'' (200 AU). We perform model calculations for the polarized flux of an optically thin debris disk which are used to determine or constrain the disk parameters of HIP 79977. Results: We measure a polarized flux contrast ratio for the disk of (Fpol)disk/F∗ = (5.5 ± 0.9) × 10-4 in the VBB filter. The surface brightness of the polarized flux reaches a maximum of SBmax = 16.2 mag arcsec-2 at a separation of 0.2''-0.5'' along the disk spine with a maximum surface brightness contrast of 7.64 mag arcsec-2. The polarized flux has a minimum near the star 1''. This can be explained by a radial blow-out of small grains. The data are modelled as a circular dust belt with a well defined disk inclination I = 85( ± 1.5)° and a radius between r0 = 60 and 90 AU. The radial

  2. ROGER a potential orbital space debris removal system

    Science.gov (United States)

    Starke, Juergen; Bischof, Bernd; Foth, W.-O.; -J., J.; Günther

    The previous activities in the field of On Orbit Servicing studied in the 1990's included in partic-ular the capability of vehicles in GEO to capture and support satellites (mainly communication satellites) to enable repair and continuation of operations, and finally the controlled transfer the target into a permanent graveyard orbit. The specific capture tools for these applications were mostly based on robotic systems to capture and fix the target under specific dynamic constraints (e.g. slowly tumbling target) without damage, and to allow the stabilization, re-orientation and potential repair of the target and subsequent release or transport to the final disposal orbit. Due to the drastically increasing number of debris particularly in the Low Earth Orbits (SSO) the active debris removal is now necessary to counteract to the predicted debris production cascade (Kessler Syndrome), which means the pollution of the total sphere in low earth orbit and not only the SSO area. In most of the debris congresses it was recommended to start removal with the still integrated systems as soon as possible. In the case of large debris objects, the soft capture system can be replaced by a simpler and robust system able to operate from a safe distance to the target and flexible enough to capture and hold different types of targets such as deactivated and/or defective satellites, upper stages and big fragments. These nominally non -cooperative targets might be partially destroyed by the capture process, but the production of additional debris shall be avoided. A major argument for the commercial applications is a multi-target mission potential, which is possible at GEO because the transfer propellant requirement to the disposal orbit and the return to the orbit of the next potential target is relative low (orbits with similar inclination and altitude). The proposed ROGER system is designed as a spacecraft with rendezvous capabilities including inspection in the vicinity of the

  3. Relationship between the accumulation of sediment storage and debris-flow characteristics in a debris-flow initiation zone, Ohya landslide body, Japan

    Directory of Open Access Journals (Sweden)

    F. Imaizumi

    2017-11-01

    Full Text Available Debris flows usually occur in steep mountain channels and can be extremely hazardous as a result of their destructive power, long travel distance, and high velocity. However, their characteristics in the initiation zones, which could possibly be affected by temporal changes in the accumulation conditions of the storage (i.e., channel gradient and volume of storage associated with sediment supply from hillslopes and the evacuation of sediment by debris flows, are poorly understood. Thus, we studied the relationship between the flow characteristics and the accumulation conditions of the storage in an initiation zone of debris flow at the Ohya landslide body in Japan using a variety of methods, including a physical analysis, a periodical terrestrial laser scanning (TLS survey, and field monitoring. Our study clarified that both partly and fully saturated debris flows are important hydrogeomorphic processes in the initiation zones of debris flow because of the steep terrain. The predominant type of flow varied temporally and was affected by the volume of storage and rainfall patterns. Fully saturated flow dominated when the total volume of storage was  <  10 000 m3, while partly saturated flow dominated when the total volume of the storage was  >  15 000 m3. Debris flows form channel topography which reflects the predominant flow types during debris-flow events. Partly saturated debris flow tended to form steeper channel sections (22.2–37.3°, while fully saturated debris flow tended to form gentler channel sections ( <  22.2°. Such relationship between the flow type and the channel gradient could be explained by a simple analysis of the static force at the bottom of the sediment mass.

  4. Forensic analyses of explosion debris from the January 2, 1992 Pd/D{sub 2}O electrochemistry incident at SRI International

    Energy Technology Data Exchange (ETDEWEB)

    Andresen, B.; Whipple, R.; Vandervoort, D.; Grant, P.

    1992-08-15

    The January 2, 1992 explosion in an electrochemistry laboratory at SRI International (SRI) resulted in the death of scientist Andrew Riley, and gained some notoriety due to its association with experimental work in the controversial field of cold fusion research. Selected components of explosion debris were subjected to forensic analyses at LLNL to elucidate potential causes of, or contributing factors to, the explosion. Interrogation of the debris by LLNL encompassed nuclear, chemical, physical, and materials investigations. Nuclear studies for the determination of tritium and neutron-activation products in stainless steel and brass were negative. No evidence of signature species indicative of orthodox nuclear events was detected. The inorganic and particulate analyses were likewise negative with respect to residues of unexpected chemical species. Such target compounds included conventional explosives, accelerants, propellants, or any exceptional industrial chemicals. The GC-MS analyses of trace organic components in the explosion debris provided perhaps the most interesting results obtained at LLNL. Although no evidence of organic explosives, oxidizers, or other unusual compounds was detected, the presence of a hydrocarbon oil in the interior of the electrochemical cell was established. It is likely that its source was lubricating fluid from the machining of the metal cell components. If residues of organic oils are present during electrolysis experiments, the potential exists for an explosive reaction in the increasingly enriched oxygen atmosphere within the headspace of a metal cell.

  5. Deposition of steeply infalling debris around white dwarf stars

    Science.gov (United States)

    Brown, John C.; Veras, Dimitri; Gänsicke, Boris T.

    2017-06-01

    High-metallicity pollution is common in white dwarf (WD) stars hosting remnant planetary systems. However, they rarely have detectable debris accretion discs, possibly because much of the influx is fast steeply infalling debris in star-grazing orbits, producing a more tenuous signature than a slowly accreting disc. Processes governing such deposition between the Roche radius and photosphere have so far received little attention and we model them here analytically by extending recent work on sun-grazing comets to WD systems. We find that the evolution of cm-to-km size (a0) infallers most strongly depends on two combinations of parameters, which effectively measure sublimation rate and binding strength. We then provide an algorithm to determine the fate of infallers for any WD, and apply the algorithm to four limiting combinations of hot versus cool (young/old) WDs with snowy (weak, volatile) versus rocky (strong, refractory) infallers. We find: (I) Total sublimation above the photosphere befalls all small infallers across the entire WD temperature (TWD) range, the threshold size rising with TWD and 100× larger for rock than snow. (II) All very large objects fragment tidally regardless of TWD: for rock, a0 ≽ 105 cm; for snow, a0 ≽ 103-3 × 104 cm across all WD cooling ages. (III) A considerable range of a0 avoids fragmentation and total sublimation, yielding impacts or grazes with cold WDs. This range rapidly narrows with increasing TWD, especially for snowy bodies. Finally, we briefly discuss how the various forms of deposited debris may finally reach the photosphere surface itself.

  6. Alternative mannosylation method for nanomaterials: application to oxidized debris-free multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Marcelo de, E-mail: marcelosousap2@yahoo.com.br [University of Campinas (Unicamp), Solid State Chemistry Laboratory (LQES) and NanoBioss Laboratory, Institute of Chemistry (Brazil); Martinez, Diego Stéfani Teodoro, E-mail: diego.martinez@lnnano.cnpem.br [Brazilian Center for Research in Energy and Materials (CNPEM), Brazilian Nanotechnology National Laboratory (LNNano) (Brazil); Alves, Oswaldo Luiz, E-mail: oalves@iqm.unicamp.br [University of Campinas (Unicamp), Solid State Chemistry Laboratory (LQES) and NanoBioss Laboratory, Institute of Chemistry (Brazil)

    2016-06-15

    Mannosylation is a method commonly used to deliver nanomaterials to specific organs and tissues via cellular macrophage uptake. In this work, for the first time, we proposed a method that involves the binding of d-mannose to ethylenediamine to form mannosylated ethylenediamine, which is then coupled to oxidized and purified multiwalled carbon nanotubes. The advantage of this approach is that mannosylated ethylenediamine precipitates in methanol, which greatly facilitates the separation of this product in the synthesis process. Carbon nanotubes were oxidized using concentrated H{sub 2}SO{sub 4} and HNO{sub 3} by conventional reflux method. However, during this oxidation process, carbon nanotubes generated carboxylated carbonaceous fragments (oxidation debris). These by-products were removed from the oxidized carbon nanotubes to ensure that the functionalization would occur only on the carbon nanotube surface. The coupling of mannosylated ethylenediamine to debris-free carbon nanotubes was accomplished using n-(3-dimethylaminopropyl)-n-ethylcarbodiimide and n-hydroxysuccinimide. Deconvoluted N1s spectra obtained from X-ray photoelectron spectroscopy gave binding energies of 399.8 and 401.7 eV, which we attributed to the amide and amine groups, respectively, of carbon nanotubes functionalized with mannosylated ethylenediamine. Deconvoluted O1s spectra showed a binding energy of 532.4 eV, which we suggest is caused by an overlap in the binding energies of the aliphatic CO groups of d-mannose and the O=C group of the amide bond. The functionalization degree was approximately 3.4 %, according to the thermogravimetric analysis. Scanning electron microscopy demonstrated that an extended carbon nanotube morphology was preserved following the oxidation, purification, and functionalization steps.

  7. Studies of fluid instabilities in flows of lava and debris

    International Nuclear Information System (INIS)

    Fink, J.H.

    1987-01-01

    At least two instabilities have been identified and utilized in lava flow studies: surface folding and gravity instability. Both lead to the development of regularly spaced structures on the surfaces of lava flows. The geometry of surface folds have been used to estimate the rheology of lava flows on other planets. One investigation's analysis assumed that lava flows have a temperature-dependent Newtonian rheology, and that the lava's viscosity decreased exponentially inward from the upper surface. The author reviews studies by other investigators on the analysis of surface folding, the analysis of Taylor instability in lava flows, and the effect of surface folding on debris flows

  8. Debris Flow as a Mechanism for Forming Martian Gullies

    Science.gov (United States)

    Conway, S. J.; Balme, M. R.; Murray, J. B.; Towner, M. C.

    2009-04-01

    The current low temperatures and pressures at the martian surface are not conducive to the stability of liquid water; hence the discovery of recently active, fluvial-like gullies [1, 2] presents an apparent paradox: how can these fluvial landforms have occurred if water is not stable at the surface? To approach this problem we have compared the morphometric properties of gullies in various settings on Earth to those of gullies on Mars. We have measured debris flows in Westfjords, Iceland [3] and gullies in La Gomera, Canary Islands [4]. The Iceland elevation data were generated from differential GPS and a LiDAR survey, and the La Gomera data from differential GPS. In addition we used elevation data from the Shuttle Radar Topography Mission (SRTM) extracted along previously mapped debris flows in the Taurids Mountains, Turkey [5] and the Colorado Front Range, USA [6]. We have compared these data to preliminary analyses of stereo HiRISE images of martian gullies in four locations using a method to extract point elevation data developed by Kreslavsky [7]. In all cases the elevation along the centre channel of the debris flow or gully was used for comparison to Mars. For Iceland and La Gomera we also extracted cross-profiles for comparison with martian gullies. Simply comparing the longitudinal profiles of gullies on Mars and different situations on the Earth highlights the variability between debris flow sites on Earth. The martian gully profiles are most similar to debris flows in the Taurids Mountains and in the Colorado Front Range. The overall slope is shallower on Mars compared to the Iceland debris flows and the ephemeral water flow gullies in La Gomera. The runout or total length of gullies is also more variable and greater for Mars than for Iceland and La Gomera. Caution should be taken in interpreting the cross profiles for Mars as the error on the elevation is at least 1m and there is low sampling density in comparison to the other datasets. The v-shaped La

  9. Debris Removal Project K West Canister Cleaning System Performance Specification

    International Nuclear Information System (INIS)

    FARWICK, C.C.

    1999-01-01

    Approximately 2,300 metric tons Spent Nuclear Fuel (SNF) are currently stored within two water filled pools, the 105 K East (KE) fuel storage basin and the 105 K West (KW) fuel storage basin, at the U.S. Department of Energy, Richland Operations Office (RL). The SNF Project is responsible for operation of the K Basins and for the materials within them. A subproject to the SNF Project is the Debris Removal Subproject, which is responsible for removal of empty canisters and lids from the basins. Design criteria for a Canister Cleaning System to be installed in the KW Basin. This documents the requirements for design and installation of the system

  10. Micro-satellite for space debris observation by optical sensors

    Science.gov (United States)

    Thillot, Marc; Brenière, Xavier; Midavaine, Thierry

    2017-11-01

    The purpose of this theoretical study carried out under CNES contract is to analyze the feasibility of small space debris detection and classification with an optical sensor on-board micro-satellite. Technical solutions based on active and passive sensors are analyzed and compared. For the most appropriated concept an optimization was made and theoretical performances in terms of number of detection versus class of diameter were calculated. Finally we give some preliminary physical sensor features to illustrate the concept (weight, volume, consumption,…).

  11. The Tancitaro Debris Avalanche: Characterization, propagation and modeling

    Science.gov (United States)

    Morelli, Stefano; Monroy, Victor Hugo Garduño; Gigli, Giovanni; Falorni, Giacomo; Rocha, Eleazar Arreygue; Casagli, Nicola

    2010-06-01

    The Tancitaro volcano (3860 m) is an andesitic-dacitic stratovolcano located in the western portion of the Trans-Mexican Volcanic Belt within the state of Michoacán (Mexico). The tectonic activity of this area has likely contributed to a large sector collapse of the volcano. The first findings of a multidisciplinary investigation into this debris avalanche are presented here. Geomorphological analyses, based on the interpretation of orthophotos, satellite imagery and on GIS elaborations, had the objective of determining the main morphometric features of the landslide. The collapse structure is an east-facing horseshoe-shaped crater (4 km wide and 5.3 km long), while the deposit forms a large fan that is 66 km long, covers an area of approximately 1155 km 2 and has an estimated volume of 18 km 3. Event volume was established by reconstructing the paleo-edifice in a GIS and taking into account volumetric expansion. Cross sections measured in the field were also used for this purpose. Field investigations also highlighted the presence of two texturally distinct units, which are referred to as the "block facies" and the "matrix facies", respectively. The first is responsible for the typical hummock morphologies found in the proximal area. A transitional zone contains a "mixed block and matrix facies" while in the distal portion blocks and megablocks, some of which have a jigsaw puzzle texture, gradually decrease in size until they disappear entirely. A number of matrix samples were collected to conduct direct shear tests, granulometric analyses and classification of the materials. The data and analyses described above were used to discuss the mechanism controlling the long runout of the avalanche. Based on the comparison between the Tancitaro debris avalanche and similar events we propose that mechanical fluidization was the mechanism responsible for the remarkable mobility of the landslide. The predisposing factors leading to the collapse were also considered. Field

  12. Planetary systems in polarized light: Debris disk observations and instrumentation

    Science.gov (United States)

    Millar-Blanchaer, Maxwell A.

    Understanding planet formation is one of the major challenges of modern astronomy. Polarimetry is a powerful tool with which we can confront this challenge. In particular, polarimetric observations can be useful for imaging debris disks and characterizing exoplanet atmospheres. With that in mind, this thesis has been constructed with two main aspects: i) observational studies of two debris disk systems, beta Pic and HD 157587, using the Gemini Planet Imager and ii) the characterization and testing of a new type of diffraction grating, called a polarization grating, that we plan to use for future observations of exoplanet atmospheres. The Gemini Planet Imager is a high-contrast imager that includes a polarimetry mode designed to image circumstellar disks. Here we detail the development of new data analysis techniques that reduce systematics and noise in processed GPI data. We apply these techniques to observations of the beta Pic and HD 157587 debris disks and then fit each disk image to a geometric disk model. The beta Pic disk model's morphology cannot be explained by interactions with the planet beta Pic b, and the presence of a second planet could be invoked to explain the discrepancy. In the case of HD 157587, the disk model's geometric centre is offset from the location of the star, which could be explained by a perturbing planet. Characterization of the planets' interactions with their debris disks is a critical method to gain more information about these two systems. The second component of this thesis focuses on polarization gratings, thin film optical devices that can simultaneously act as polarizing beam splitters and as spectral dispersive elements. Moreover, they can be designed for high diffraction efficiency across a broad wavelength range. These features make polarization gratings useful for many types of astronomical observations. We have carried out laboratory and on-sky test observations using a polarization grating optimized for visible

  13. Scaling up debris-flow experiments on a centrifuge

    Science.gov (United States)

    Hung, C.; Capart, H.; Crone, T. J.; Grinspum, E.; Hsu, L.; Kaufman, D.; Li, L.; Ling, H.; Reitz, M. D.; Smith, B.; Stark, C. P.

    2013-12-01

    Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Formulation of an erosion-rate law for debris flows is therefore a high priority, and it makes sense to build such a law around laboratory experiments. However, running experiments big enough to generate realistic boundary forces is a logistical challenge to say the least [1]. One alternative is to run table-top simulations with unnaturally weak but fast-eroding pseudo-bedrock, another is to extrapolate from micro-erosion of natural substrates driven by unnaturally weak impacts; hybrid-scale experiments have also been conducted [2]. Here we take a different approach in which we scale up granular impact forces by running our experiments under enhanced gravity in a geotechnical centrifuge [3]. Using a 40cm-diameter rotating drum [2] spun at up to 100g, we generate debris flows with an effective depth of over several meters. By varying effective gravity from 1g to 100g we explore the scaling of granular flow forces and the consequent bed and wall erosion rates. The velocity and density structure of these granular flows is monitored using laser sheets, high-speed video, and particle tracking [4], and the progressive erosion of the boundary surfaces is measured by laser scanning. The force structures and their fluctuations within the granular mass and at the boundaries are explored with contact dynamics numerical simulations that mimic the lab experimental conditions [5]. In this presentation we summarize these results and discuss how they can contribute to the formulation of debris-flow erosion law. [1] Major, J. J. (1997), Journal of Geology 105: 345-366, doi:10.1086/515930 [2] Hsu, L. (2010), Ph.D. thesis, University of California, Berkeley [3] Brucks, A., et al (2007), Physical Review E 75, 032301, doi:10.1103/PhysRevE.75.032301 [4] Spinewine, B., et al (2011), Experiments in Fluids 50: 1507-1525, doi: 10.1007/s00348

  14. Engagement of Metal Debris into a 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.

  15. Immobilization of Three-Mile Island core debris

    International Nuclear Information System (INIS)

    The immobilization of Three-Mile Island core debris in iron-enriched basalt (IEB), a fused-cast nuclear waste form, was considered. The amount of zirconium clad UO 2 fuel assemblies that can be dissolved in IEB using the Zr to UO 2 ratio present in the core was bracketed between 25 and 30% at 1500 0 C. The factors controlling the rate of dissolution of fuel pellets and Inconel, a structural component of the core, were investigated. Since the UO 2 dissolved in IEB could be a valuable resource in the future, the recovery of uranium from IEB using conventional ore-dressing and leaching techniques was assessed

  16. PRESENT STATUS OF RESEARCH IN DEBRIS FLOW MODELING.

    Science.gov (United States)

    Chen, Cheng-lung

    1985-01-01

    A viable rheological model should consist of both a time-independent part and a time-dependent part. A generalized viscoplastic fluid model that has both parts as well as two major rheological properties (i. e. , the normal stress effect and soil yield criteria) is shown to be sufficiently accurate, yet practical, for general use in debris flow modeling. Other rheological models, such as the Bingham plastic fluid model and the so-called Coulomb-viscous model, are compared in terms of the generalized viscoplastic fluid model.

  17. Gas Debris Disks: A New Way to Produce Dust Patterns

    Science.gov (United States)

    Kuchner, Marc J.

    2012-01-01

    Debris disks like those around Fomalhaut and Beta Pictoris show striking dust patterns often attributed to planets. But adding a bit of gas to our models of these disks--too little to detect-could 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. rll discuss these phenomena and whether or not we can still use dust patterns as indicators of hidden exoplanets.

  18. Interstellar Explorer Observations of the Solar System's Debris Disks

    Science.gov (United States)

    Lisse, C. M.; McNutt, R. L., Jr.; Brandt, P. C.

    2017-12-01

    Planetesimal belts and debris disks full of dust are known as the "signposts of planet formation" in exosystems. The overall brightness of a disk provides information on the amount of sourcing planetesimal material, while asymmetries in the shape of the disk can be used to search for perturbing planets. The solar system is known to house two such belts, the Asteroid belt and the Kuiper Belt; and at least one debris cloud, the Zodiacal Cloud, sourced by planetisimal collisions and Kuiper Belt comet evaporative sublimation. However these are poorly understood in toto because we live inside of them. E.g., while we know of the two planetesimal belt systems, it is not clear how much, if any, dust is produced from the Kuiper belt since the near-Sun comet contributions dominate near-Earth space. Understanding how much dust is produced in the Kuiper belt would give us a much better idea of the total number of bodies in the belt, especially the smallest ones, and their dynamical collisional state. Even for the close in Zodiacal cloud, questions remain concerning its overall shape and orientation with respect to the ecliptic and invariable planes of the solar system - they aren't explainable from the perturbations caused by the known planets alone. In this paper we explore the possibilities of using an Interstellar Explorer telescope placed at 200 AU from the sun to observe the brightness, shape, and extent of the solar system's debris disk(s). We should be able to measure the entire extent of the inner, near-earth zodiacal cloud; whether it connects smoothly into an outer cloud, or if there is a second outer cloud sourced by the Kuiper belt and isolated by the outer planets, as predicted by Stark & Kuchner (2009, 2010) and Poppe et al. (2012, 2016; Figure 1). VISNIR imagery will inform about the dust cloud's density, while MIR cameras will provide thermal imaging photometry related to the cloud's dust particle size and composition. Observing at high phase angle by looking

  19. Drag reduction in channel flow using nonlinear control

    Science.gov (United States)

    Keefe, Laurence R.

    1993-01-01

    Two nonlinear control schemes have been applied to the problem of drag reduction in channel flow. Both schemes have been tested using numerical simulations at a mass flux Reynolds numbers of 4408, utilizing 2D nonlinear neutral modes for goal dynamics. The OGY-method, which requires feedback, reduces drag to 60-80 percent of the turbulent value at the same Reynolds number, and employs forcing only within a thin region near the wall. The H-method, or model-based control, fails to achieve any drag reduction when starting from a fully turbulent initial condition, but shows potential for suppressing or retarding laminar-to-turbulent transition by imposing instead a transition to a low drag, nonlinear traveling wave solution to the Navier-Stokes equation. The drag in this state corresponds to that achieved by the OGY-method. Model-based control requires no feedback, but in experiments to date has required the forcing be imposed within a thicker layer than the OGY-method. Control energy expenditures in both methods are small, representing less than 0.1 percent of the uncontrolled flow's energy.

  20. Debris flow grain size scales with sea surface temperature over glacial-interglacial timescales

    Science.gov (United States)

    D'Arcy, Mitch; Roda Boluda, Duna C.; Whittaker, Alexander C.; Araújo, João Paulo C.

    2015-04-01

    Debris flows are common erosional processes responsible for a large volume of sediment transfer across a range of landscapes from arid settings to the tropics. They are also significant natural hazards in populated areas. However, we lack a clear set of debris flow transport laws, meaning that: (i) debris flows remain largely neglected by landscape evolution models; (ii) we do not understand the sensitivity of debris flow systems to past or future climate changes; and (iii) it remains unclear how to interpret debris flow stratigraphy and sedimentology, for example whether their deposits record information about past tectonics or palaeoclimate. Here, we take a grain size approach to characterising debris flow deposits from 35 well-dated alluvial fan surfaces in Owens Valley, California. We show that the average grain sizes of these granitic debris flow sediments precisely scales with sea surface temperature throughout the entire last glacial-interglacial cycle, increasing by ~ 7 % per 1 ° C of climate warming. We compare these data with similar debris flow systems in the Mediterranean (southern Italy) and the tropics (Rio de Janeiro, Brazil), and find equivalent signals over a total temperature range of ~ 14 ° C. In each area, debris flows are largely governed by rainfall intensity during triggering storms, which is known to increase exponentially with temperature. Therefore, we suggest that these debris flow systems are transporting predictably coarser-grained sediment in warmer, stormier conditions. This implies that debris flow sedimentology is governed by discharge thresholds and may be a sensitive proxy for past changes in rainfall intensity. Our findings show that debris flows are sensitive to climate changes over short timescales (≤ 104 years) and therefore highlight the importance of integrating hillslope processes into landscape evolution models, as well as providing new observational constraints to guide this. Finally, we comment on what grain size