WorldWideScience

Sample records for street deposited sediments

  1. Earth Surface Processes, Landforms and Sediment Deposits

    Science.gov (United States)

    Bridge, John; Demicco, Robert

    Earth surface processes, landforms and sediment deposits are intimately related - involving erosion of rocks, generation of sediment, and transport and deposition of sediment through various Earth surface environments. These processes, and the landforms and deposits that they generate, have a fundamental bearing on engineering, environmental and public safety issues; on recovery of economic resources; and on our understanding of Earth history. This unique textbook brings together the traditional disciplines of sedimentology and geomorphology to explain Earth surface processes, landforms and sediment deposits in a comprehensive and integrated way. It is the ideal resource for a two-semester course in sedimentology, stratigraphy, geomorphology, and Earth surface processes from the intermediate undergraduate to beginning graduate level. The book is also accompanied by a website hosting illustrations and material on field and laboratory methods for measuring, describing and analyzing Earth surface processes, landforms and sediments.

  2. Sediment problems in reservoirs. Control of sediment deposits

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, Tom

    1997-12-31

    When a reservoir is formed on a river, sediment will deposit in the reservoir. Such processes are unfortunate, for instance, for the implementation of hydroelectric energy. This thesis studies the problem of reservoir sedimentation and discusses methods of removing the sediments. Various aspects of reservoir sedimentation are discussed. Anthropogenic impacts seem to greatly affect the erosion processes. Temporal distribution is uneven, mainly because of the very large flood events. A world map showing the Reservoir Capacity: Annual Sediment Inflow ratio for reservoirs with volume equal to 10% of annual inflow has been prepared. The map shows that sedimentation is severe in the western parts of North and South America, eastern, southern and northern Africa, parts of Australia and most of Asia. The development of medium-sized reservoirs is difficult, as they are too large for conventional flushing technique and too small to store the sediment that accumulates during their economic lifetime. A computer model, SSIIM, was used with good results in a case study of two flood drawdown trials in Lake Roxburg, New Zealand. Two techniques have been developed that permits controlled suction of sediment and water into a pipe: the Slotted Pipe Sediment Sluicer (SPSS) and the Saxophone Sediment Sluicer (SSS). The techniques exploit the inflow pattern in through a slot in a pipe. An equation describing this inflow pattern was derived and verified experimentally. The SPSS is fixed near the reservoir bed, and sediment that deposits on top of it is removed in the sluicing process. The SSS sluices sediment from the surface of the sediment deposits. Some technical and economic conditions affecting the economics of sediment removal from reservoirs have been identified and studied. 79 refs., 112 figs., 14 tabs.

  3. Research on Granular Media of Stormwater Sediments (On the Street and Stormwater Treatment Plants

    Directory of Open Access Journals (Sweden)

    Ginta Cholomskytė

    2011-04-01

    Full Text Available In water management, to reach optimal exploitation of stormwater net it is required to value particle size witch accumulate on the roads and ways. The sediments from stormwater sedimentation tanks, sediments from Kalvarijų street and from the industrial area (Greičiūno street 35 were taken. Was established particle size of sediments. Research showed that the biggest part of sediments 80% in sedimentation tank (Verkiai ir Karoliniškės compose the smallest parts, size – 0,25 mm. Sample from the road that particles size 0,25 compose only 25-35%. To reduce negative effect to the stormwater net exploitation it is recommended to implement street sweeping.Article in Lithuanian

  4. Analysis of heavy metals in road-deposited sediments.

    Science.gov (United States)

    Herngren, Lars; Goonetilleke, Ashantha; Ayoko, Godwin A

    2006-07-07

    Road-deposited sediments were analysed for heavy metal concentrations at three different landuses (residential, industrial, commercial) in Queensland State, Australia. The sediments were collected using a domestic vacuum cleaner which was proven to be highly efficient in collecting sub-micron particles. Five particle sizes were analysed separately for eight heavy metal elements (Zn, Fe, Pb, Cd, Cu, Cr, Al and Mn). At all sites, the maximum concentration of the heavy metals occurred in the 0.45-75 microm particle size range, which conventional street cleaning services do not remove efficiently. Multicriteria decision making methods (MCDM), PROMETHEE and GAIA, were employed in the data analysis. PROMETHEE, a non-parametric ranking analysis procedure, was used to rank the metal contents of the sediments sampled at each site. The most polluted site and particle size range were the industrial site and the 0.45-75 microm range, respectively. Although the industrial site displayed the highest metal concentrations, the highest heavy metal loading coincided with the highest sediment load, which occurred at the commercial site. GAIA, a special form of principal component analysis, was applied to determine correlations between the heavy metals and particle size ranges and also to assess possible correlation with total organic carbon (TOC). The GAIA-planes revealed that irrespective of the site, most of the heavy metals are adsorbed to sediments below 150 microm. A weak correlation was found between Zn, Mn and TOC at the commercial site. This could lead to higher bioavailability of these metals through complexation reactions with the organic species in the sediments.

  5. Anthropogenic mercury deposition to arctic lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Hermanson, M.H. [Westchester University, Westchester, PA (United States). Dept. of Health

    1998-01-01

    The history of atmospheric mercury inputs to remote arctic regions can be measured in lake sediment cores using lead-210 chronology. In the investigation, total mercury deposition is measured in sediments from Imitavik and Annak Lakes on the Belcher Islands in southeastern Hudson Bay, an area in the southern Canadian Arctic with no history of local industrial or agricultural sources of contamination. Both lakes received background and atmospheric inputs of mercury while Annak also received mercury from raw domestic sewage from the Hamlet of Sanikiluaq, a growing Inuit community of about 550 established in the late 1960s. Results from Imitavik show that anthropogenic mercury inputs, apparently transported through the atmosphere, began to appear in the mid-eighteenth century, and continued to the 1990s. Annak had a similar mercury history until the late 1960s when disposal of domestic sewage led to increased sediment and contaminant accumulation. The high input of mercury to Annak confirms that Sanikiluaq residents are exposed to mercury through native food sources. 39 refs., 7 figs., 3 tabs.

  6. Study of traffic-related pollutant removal from street canyon with trees: dispersion and deposition perspective.

    Science.gov (United States)

    Morakinyo, Tobi Eniolu; Lam, Yun Fat

    2016-11-01

    Numerical experiments involving street canyons of varying aspect ratio with traffic-induced pollutants (PM 2.5 ) and implanted trees of varying aspect ratio, leaf area index, leaf area density distribution, trunk height, tree-covered area, and tree planting pattern under different wind conditions were conducted using a computational fluid dynamics (CFD) model, ENVI-met. Various aspects of dispersion and deposition were investigated, which include the influence of various tree configurations and wind condition on dispersion within the street canyon, pollutant mass at the free stream layer and street canyon, and comparison between mass removal by surface (leaf) deposition and mass enhancement due to the presence of trees. Results revealed that concentration level was enhanced especially within pedestrian level in street canyons with trees relative to their tree-free counterparts. Additionally, we found a dependence of the magnitude of concentration increase (within pedestrian level) and decrease (above pedestrian level) due to tree configuration and wind condition. Furthermore, we realized that only ∼0.1-3 % of PM 2.5 was dispersed to the free stream layer while a larger percentage (∼97 %) remained in the canyon, regardless of its aspect ratio, prevailing wind condition, and either tree-free or with tree (of various configuration). Lastly, results indicate that pollutant removal due to deposition on leaf surfaces is potentially sufficient to counterbalance the enhancement of PM 2.5 by such trees under some tree planting scenarios and wind conditions.

  7. Preservation of Urban Archaeological Deposits: monitoring and characterisation of archaeological deposits at Marks & Spencer, 44-45 Parliament Street, York

    Directory of Open Access Journals (Sweden)

    M. Davis

    2002-03-01

    Full Text Available The City of York Council has been pursuing a strict policy of in situ preservation of archaeological deposits since April 1990. Planning consent is normally granted in the historic core of York for a new development so long as less than 5% of the archaeological deposits that are preserved on a site are destroyed. During archaeological evaluation work carried out as part of the redevelopment and expansion proposals for Marks & Spencer plc on Parliament Street, deposit monitoring devices were installed to investigate and monitor both the character of the archaeological deposits present and also the burial environment surrounding them (of particular importance because the burial environment, in terms both of its characteristics and stability, is thought to play a vital role in the preservation in situ of a site's archaeological deposits. The monitoring programme was undertaken between June 1995 and April 1998. As a result the data from a total of 30 site visits have been collected and are presented in this report. This article discusses results of the deposit monitoring project and presents evidence of changes that appear to be taking place in the archaeological deposits. Although the lower deposits at Parliament Street are stable, the upper deposits show considerable seasonal variations. The concept of preservation of archaeological deposits in situ is now deeply embedded both in Codes of Professional Conduct (IFA Code of Conduct and in national policy guidance (PPG 16. However, this emphasis on preservation in situ has been criticised. Does conservation archaeology in general and the City of York policy in particular achieve the preservation of the remaining 95% of the archaeology? Or are these deposits condemned to unseen, unrecorded destruction, sealed below new buildings; indeed if this is the case, shouldn't these deposits be excavated now while they are still viable?

  8. Land use-related chemical composition of street sediments in Beijing.

    Science.gov (United States)

    Kuang, Cen; Neumann, Thomas; Norra, Stefan; Stüben, Doris

    2004-01-01

    More than 10 million people are currently living in Beijing. This city faces severe anthropogenic air pollution caused by an intense vehicle increase (11% per year in China), coal combusting power plants, heavy industry, huge numbers of household and restaurant cookers, and domestic heating stoves. Additionally, each year dust storms are carrying particulate matter from the deserts of Gobi and Takla Makan towards Beijing, especially in spring. Other geogenic sources of particulate matter which contribute to the air pollution are bare soils, coal heaps and construction sites occurring in and around Beijing. Streets function as receptor surfaces for atmospheric dusts. Thus, street sediments consist of particles of different chemical compositions from many different sources, such as traffic, road side soils and industry. Distributions and concentrations of various chemical elements in street sediments were investigated along a rural-urban transect in Beijing, China. Chemical elements were determined with X-ray fluorescence analysis. Factor analysis was used to extract most important element sources contributing to particulate pollution along a main arterial route of the Chinese capital. The statistical evaluation of the data by factor analysis identifies three main anthropogenic sources responsible for the contamination of Beijing street sediments. The first source is a steel factory in the western part of Beijing. From this source, Mn, Fe, and Ti were emitted into the atmosphere through chimneys and by wind from coal heaps used as the primary energy source for the factory. The second source is a combination of traffic, domestic heating and some small factories in the center of Beijing discharging Cu, Pb, Zn and Sn. Calcium and Cr characterize a third anthropogenic element source of construction materials such as concrete and mortar. Beside the anthropogenic contamination, some elements like Y, Zr, Nb, Ce, and Rb are mainly derived from natural soils and from the

  9. Sedimentation Deposition Patterns on the Chukchi Shelf Using Radionuclide Inventories

    Science.gov (United States)

    Cooper, L. W.; Grebmeier, J. M.

    2016-02-01

    Sediment core collections and assays of the anthropogenic and natural radioisotopes, 137Cs and 210Pb, respectively, are providing long-term indications of sedimentation and current flow processes on the Chukchi and East Siberian sea continental shelf. This work, which has been integrated into interdisciplinary studies of the Chukchi Sea supported by both the US Bureau of Ocean Energy Management (COMIDA Hanna Shoal Project) and the National Oceanic and Atmospheric Administration (Russian-US Long Term Census of the Arctic, RUSALCA) includes studies of total radiocesium inventories, sedimentation rate determinations, where practical, and depths of maxima in radionuclide deposition. Shallow maxima in the activities of the anthropogenic radionuclide in sediment cores reflect areas with higher current flow (Barrow Canyon and Herald Canyon; 3-6 cm) or low sedimentation (Hanna Shoal; 1-3 cm). The first sedimentation studies from Long Strait are consistent with quiescent current conditions and steady recent sedimentation of clay particles. Elsewhere, higher and more deeply buried radionuclide inventories (> 2 mBq cm-2 at 15-17 cm depth) in the sediments correspond to areas of high particle deposition north of Bering Strait where bioturbation in productive sediments is also clearly an important influence. Radiocesium activities from bomb fallout dating to 1964 are now present at low levels (20 cm. Independent sedimentation rate measurements with the natural radionuclide 210Pb are largely consistent with the radiocesium measurements.

  10. Modeling transport and deposition of the Mekong River sediment

    Science.gov (United States)

    Xue, Zuo; He, Ruoying; Liu, J. Paul; Warner, John C.

    2012-01-01

    A Coupled Wave–Ocean–SedimentTransport Model was used to hindcast coastal circulation and fine sedimenttransport on the Mekong shelf in southeastern Asian in 2005. Comparisons with limited observations showed that the model simulation captured the regional patterns and temporal variability of surface wave, sea level, and suspended sediment concentration reasonably well. Significant seasonality in sedimenttransport was revealed. In summer, a large amount of fluvial sediments was delivered and deposited near the MekongRiver mouth. In the following winter, strong ocean mixing, and coastal current lead to resuspension and southwestward dispersal of a small fraction of previously deposited sediments. Model sensitivity experiments (with reduced physics) were performed to investigate the impact of tides, waves, and remotely forced ambient currents on the transport and dispersal of the fluvial sediment. Strong wave mixing and downwelling-favorable coastal current associated with the more energetic northeast monsoon in the winter season are the main factors controlling the southwestward along-shelf transport.

  11. Accumulation rates and sediment deposition in the northwestern Mediterranean

    Science.gov (United States)

    Zuo, Z.; Eisma, D.; Gieles, R.; Beks, J.

    As part of the EROS 2000 programme, sediment mixing and accumulation rates in the northwestern Mediterranean Sea were determined, applying the 210Pb dating method to a total of 49 cores, and the results from 29 sediment cores are presented here. On the basis of the results from the 49 sediment cores, an attempt was made to present a general picture of sediment accumulation for the area of the northwestern Mediterranean. The total deposition of sediment in the area is estimated to be of the order of 34±15 × 106 ton year-1, which is half the value reported earlier by Got and Aloisi (1990) (Continental Shelf Research, 10, 841-855) for the same region. The activity-depth profiles of 210Pb show the presence of intensive mixing in the upper layer of near-shore sediments, but little or no mixing is observed in the deep-water sediments. Based on a diffusion model, sediment mixing rates calculated from excess 210Pb gradients vary from 0·002 to 7· cm2 year-1, and the deposition rates from 0·01 to 0·60 cm year-1. A linear dependence of sedimentation rate on water depth derived from the sediment cores indicates an inverse correlation between these two. The relatively high sedimentation rates and mixing rates found near the Rhône River suggest that the contribution from the river dominates the deposition system in the northwestern Mediterranean. In the deep-water basin, however, atmospheric input and biological production are clearly more important.

  12. Spatial distribution assessment of particulate matter in an urban street canyon using biomagnetic leaf monitoring of tree crown deposited particles

    International Nuclear Information System (INIS)

    Hofman, Jelle; Stokkaer, Ines; Snauwaert, Lies; Samson, Roeland

    2013-01-01

    Recently, biomagnetic monitoring of tree leaves has proven to be a good estimator for ambient particulate concentration. This paper investigates the usefulness of biomagnetic leaf monitoring of crown deposited particles to assess the spatial PM distribution inside individual tree crowns and an urban street canyon in Ghent (Belgium). Results demonstrate that biomagnetic monitoring can be used to assess spatial PM variations, even within single tree crowns. SIRM values decrease exponentially with height and azimuthal effects are obtained for wind exposed sides of the street canyon. Edge and canyon trees seem to be exposed differently. As far as we know, this study is the first to present biomagnetic monitoring results of different trees within a single street canyon. The results not only give valuable insights into the spatial distribution of particulate matter inside tree crowns and a street canyon, but also offer a great potential as validation tool for air quality modelling. Highlights: ► Spatial distribution of tree crown deposited PM was evaluated. ► SIRM values decrease exponentially with height. ► Azimuthal effects were observed at wind exposed sides of the street canyon. ► Edge and canyon trees seem to be exposed differently. ► Biomagnetic monitoring offers a great potential as validation of air quality models. -- Biomagnetic leaf monitoring provides useful insights into the spatial distribution of particulates inside individual tree crowns and an urban street canyon in Ghent (Belgium)

  13. Avalanches of sediment form deep-marine depositions

    NARCIS (Netherlands)

    Pohl, Florian|info:eu-repo/dai/nl/34309424X

    2017-01-01

    The deep ocean is the largest sedimentary system basin on the planet. It serves as the primary storage point for all terrestrially weathered sediment that makes it beyond the near-shore environment. These deep-marine offshore deposits have become a focus of attention in exploration due to the

  14. Does deposition depth control the OSL bleaching of fluvial sediment?

    NARCIS (Netherlands)

    Cunningham, A. C.; Wallinga, J.; Hobo, N.; Versendaal, A. J.; Makaske, B.; Middelkoop, H.

    2014-01-01

    The Optically Stimulated Luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

  15. Development of Sediment Deposition Height Capacity Equation in Sewer Networks

    Science.gov (United States)

    Song, Yangho; Jo, Deokjun; Lee, Jungho

    2017-04-01

    Sediment characteristics and transport processes in sewers are markedly different from river. There is a wide range of particle densities and smaller particle size variation in sewers. Sediment supply and the available erodible material are more limited in sewers, and the diverse hydraulic characteristics in sewer systems are more unsteady. Prevention of sewer sediment accumulation, which can cause major sewer operational problems, is imperative and has been an immense concern for engineers. The effects of sediment formation in sewer systems, an appropriate sediment transport modelling with the ability to determine the location and depth of sediment deposit is needed. It is necessary to design efficiently considering the transfer and settling phenomena of the sediment coming into the sewer systems. During transport in the sewer, the minimum shear flow velocity and possible shear stress at which the sediment is transported smoothly. However, the interaction of sediment and fluid within the sewer systems has been very complex and the rigorous theoretical handling of this problem has not been developed. It is derived from the empirical values obtained from the river bed. The basic theory that particles float is based on the balance between sedimentation of particles by gravity and turbulent diffusion of fluids. There are many variables related. Representative parameters include complex phenomena due to collisions between particles, particles and fluids, and interactions between particles and tube walls. In general, the main parameters that form the boundary between the main transport and sediment are particle size, density, volume fraction, pipe diameter and gravity. As the particle size and volume concentration increase, the minimum feed rate increases and the same tendency is observed for the change of the capillary diameter. Based on this tendency, this study has developed a sediment deposition height capacity formula to take into consideration the sewer discharge

  16. Chemical constituents in sediment in Lake Pontchartrain and in street mud and canal sediment in New Orleans, Louisiana, following Hurricanes Katrina and Rita, 2005

    Science.gov (United States)

    Van Metre, Peter C.; Wilson, Jennifer T.; Horowitz, Arthur J.; Skrobialowski, Stanley C.; Foreman, William T.; Fuller, Christopher C.; Burkhardt, Mark R.; Elrick, Kent A.; Mahler, Barbara J.; Smith, James J.; Zaugg, Steven D.

    2007-01-01

    Samples of street mud, suspended and bottom sediment in canals discharging to Lake Ponchartrain, and suspended and bottom sediment in the lake were collected and analyzed for chemical constituents to help evaluate the effects of Hurricanes Katrina and Rita and the subsequent unwatering of New Orleans, Louisiana. The approach used for sampling and analysis of chemical data for the study is presented herein. Radionuclides, major and trace elements, and numerous organic compounds in sediment were analyzed. The organic compounds include organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, urban waste indicator compounds, and current-use pesticides. Methods for the analysis of urban waste indicator compounds and current-use pesticides in sediment were developed only recently.

  17. Exploiting virtual sediment deposits to explore conceptual foundations

    Science.gov (United States)

    Dietze, Michael; Fuchs, Margret; Kreutzer, Sebastian

    2017-04-01

    Geomorphic concepts and hypotheses are usually formulated based on empiric data from the field or the laboratory (deduction). After translation into models they can be applied to case study scenarios (induction). However, the other way around - expressing hypotheses explicitly by models and test these by empiric data - is a rarely touched trail. There are several models tailored to investigate the boundary conditions and processes that generate, mobilise, route and eventually deposit sediment in a landscape. Thereby, the last part, sediment deposition, is usually omitted. Essentially, there is no model that explicitly focuses on mapping out the characteristics of sedimentary deposits - the material that is used by many disciplines to reconstruct landscape evolution. This contribution introduces the R-package sandbox, a model framework that allows creating and analysing virtual sediment sections for exploratory, explanatory, forecasting and inverse research questions. The R-package sandbox is a probabilistic and rule-based model framework for a wide range of possible applications. The model framework is used here to discuss a set of conceptual questions revolving around geochemical and geochronological methods, such as: How does sample size and sample volume affect age uncertainty? What determines the robustness of sediment fingerprinting results? How does the prepared grain size of the material of interest affect the analysis outcomes? Most of the concepts used in geosciences are underpinned by a set of assumptions, whose robustness and boundary conditions need to be assessed quantitatively. The R-package sandbox is a universal and flexible tool to engage with this challenge.

  18. Evaluation of Deposited Sediment and Macroinvertebrate Metrics Used to Quantify Biological Response to Excessive Sedimentation in Agricultural Streams

    Science.gov (United States)

    Sutherland, Andrew B.; Culp, Joseph M.; Benoy, Glenn A.

    2012-07-01

    The objective of this study was to evaluate which macroinvertebrate and deposited sediment metrics are best for determining effects of excessive sedimentation on stream integrity. Fifteen instream sediment metrics, with the strongest relationship to land cover, were compared to riffle macroinvertebrate metrics in streams ranging across a gradient of land disturbance. Six deposited sediment metrics were strongly related to the relative abundance of Ephemeroptera, Plecoptera and Trichoptera and six were strongly related to the modified family biotic index (MFBI). Few functional feeding groups and habit groups were significantly related to deposited sediment, and this may be related to the focus on riffle, rather than reach-wide macroinvertebrates, as reach-wide sediment metrics were more closely related to human land use. Our results suggest that the coarse-level deposited sediment metric, visual estimate of fines, and the coarse-level biological index, MFBI, may be useful in biomonitoring efforts aimed at determining the impact of anthropogenic sedimentation on stream biotic integrity.

  19. Recent 137Cs deposition in sediments of Admiralty Bay, Antarctica

    International Nuclear Information System (INIS)

    Sanders, Christian J.; Santos, Isaac R.; Patchineelam, Sambasiva R.; Schaefer, Carlos; Silva-Filho, Emmanoel V.

    2010-01-01

    Cesium-137, radium-226 and lead-210 profiles of a 25 cm sediment core give an indication of recent changes in land-ocean interactions at a polar coastal environment (Admiralty Bay, King George Island, Antarctica). The linear sedimentation accumulation rate at the study site calculated from the unsupported 210 Pb profile was 6.7 mm/year from 1965 to 2005. A 3.5-fold increase in 137 Cs concentrations was observed in the top layer of this sediment core. This sharp increase seems to indicate a recent redistribution of fallout radionuclides previously deposited on soil, vegetation and snow. These results imply enhanced land-ocean interactions at this site likely as a result of climate change. Because our results are based on a single core, additional investigations are needed to confirm our observations.

  20. Entrainment, transport and deposition of sediment by saline gravity currents

    Science.gov (United States)

    Zordan, Jessica; Juez, Carmelo; Schleiss, Anton J.; Franca, Mário J.

    2018-05-01

    Few studies have addressed simultaneously the feedback between the hydrodynamics of a gravity current and the geomorphological changes of a mobile bed. Hydrodynamic quantities such as turbulent and mean velocities, bed shear stress and turbulent stresses undoubtedly govern the processes of entrainment, transport and deposition. On the other hand, the incorporation of entrained sediment in the current may change its momentum by introducing extra internal stresses, introducing thus a feedback process. These two main questions are here investigated. Laboratory experiments of saline gravity currents, produced by lock-exchange, flowing over a mobile bed channel reach, are here reported. Different initial buoyancies of the current in the lock are tested together with three different grain sizes of the non-coherent sediment that form the erodible bed. Results from velocity measurements are combined with the visualization of the sediment movement in the mobile reach and with post-test topographic and photo surveys of the geomorphology modifications of the channel bed. Mean and turbulent velocities are measured and bed shear stress and Reynolds stresses are estimated. We show that the mean vertical component of the velocity and bed shear stress are highly correlated with the first instants of sediment entrainment. Vertical turbulent velocity is similarly related to entrainment, although with lower correlation values, contributing as well to the sediment movement. Bed shear stress and Reynolds shear stress measured near the bed are correlated with sediment entrainment for longer periods, indicating that these quantities are associated to distal transport as well. Geomorphological changes in the mobile bed are strongly related to the impulse caused by the bed shear stress on the sediment. On the other hand, we show that the nature of the grain of the mobile bed reach influences the hydrodynamics of the current which means that a feedback mechanisms between both occurs during

  1. Measurement of Sediment Deposition Rates using an Optical Backscatter Sensor

    Science.gov (United States)

    Ridd, P.; Day, G.; Thomas, S.; Harradence, J.; Fox, D.; Bunt, J.; Renagi, O.; Jago, C.

    2001-02-01

    An optical method for measuring siltation of sediment has been developed using an optical fibre backscatter (OBS) nephelometer. Sediment settling upon the optical fibre sensor causes an increase in the backscatter reading which can be related to the settled sediment surface density (SSSD) as measured in units of mg cm -2. Calibration and laboratory tests indicate that the resolution of measurements of SSSD is 0·01 mg cm -2and an accuracy of 5% in still water. In moving water it is more difficult to determine the accuracy of the method because other methods with suitable resolution are unavailable. However, indirect methods using measurements of changing suspended sediment concentration in a ring flume, indicate that the OBS method under-predicts deposition. The series of siltation from three field sites are presented. This sensor offers considerable advances over other methods of measuring settling because time series of settling may be taken and thus settling events may be related to other hydrodynamic parameters such as wave climate and currents.

  2. Net atmospheric mercury deposition to Svalbard: Estimates from lacustrine sediments

    Science.gov (United States)

    Drevnick, Paul E.; Yang, Handong; Lamborg, Carl H.; Rose, Neil L.

    2012-11-01

    In this study we used lake sediments, which faithfully record Hg inputs, to derive estimates of net atmospheric Hg deposition to Svalbard, Norwegian Arctic. With the exception of one site affected by local pollution, the study lakes show twofold to fivefold increases in sedimentary Hg accumulation since 1850, likely due to long-range atmospheric transport and deposition of anthropogenic Hg. Sedimentary Hg accumulation in these lakes is a linear function of the ratio of catchment area to lake area, and we used this relationship to model net atmospheric Hg flux: preindustrial and modern estimates are 2.5 ± 3.3 μg m-2 y-1 and 7.0 ± 3.0 μg m-2 y-1, respectively. The modern estimate, by comparison with data for Hg wet deposition, indicates that atmospheric mercury depletion events (AMDEs) or other dry deposition processes contribute approximately half (range 0-70%) of the net flux. Hg from AMDEs may be moving in significant quantities into aquatic ecosystems, where it is a concern because of contamination of aquatic food webs.

  3. Numerical Modelling of Suspended Transport and Deposition of Highway Deposited Sediments

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Bach, Christine

    Good data for calibration and validation of numerical models are of high importance. In the natural environment data can be hard to archive and the stochastic nature have governing influence on the data archived. Hence for modelling of suspended transport and deposition of particles, originating ...... from the highway surfaces, in highway detention ponds, four experiments are carried out. To simplify the complexity of a real pond and for easy control and measurement the sediment transports where carried out in two rectangular channels....

  4. Vertical profiles of lung deposited surface area concentration of particulate matter measured with a drone in a street canyon.

    Science.gov (United States)

    Kuuluvainen, Heino; Poikkimäki, Mikko; Järvinen, Anssi; Kuula, Joel; Irjala, Matti; Dal Maso, Miikka; Keskinen, Jorma; Timonen, Hilkka; Niemi, Jarkko V; Rönkkö, Topi

    2018-05-23

    The vertical profiles of lung deposited surface area (LDSA) concentration were measured in an urban street canyon in Helsinki, Finland, by using an unmanned aerial system (UAS) as a moving measurement platform. The street canyon can be classified as an avenue canyon with an aspect ratio of 0.45 and the UAS was a multirotor drone especially modified for emission measurements. In the experiments of this study, the drone was equipped with a small diffusion charge sensor capable of measuring the alveolar LDSA concentration of particles. The drone measurements were conducted during two days on the same spatial location at the kerbside of the street canyon by flying vertically from the ground level up to an altitude of 50 m clearly above the rooftop level (19 m) of the nearest buildings. The drone data were supported by simultaneous measurements and by a two-week period of measurements at nearby locations with various instruments. The results showed that the averaged LDSA concentrations decreased approximately from 60 μm 2 /cm 3 measured close to the ground level to 36-40 μm 2 /cm 3 measured close to the rooftop level of the street canyon, and further to 16-26 μm 2 /cm 3 measured at 50 m. The high-resolution measurement data enabled an accurate analysis of the functional form of vertical profiles both in the street canyon and above the rooftop level. In both of these regions, exponential fits were used and the parameters obtained from the fits were thoroughly compared to the values found in literature. The results of this study indicated that the role of turbulent mixing caused by traffic was emphasized compared to the street canyon vortex as a driving force of the dispersion. In addition, the vertical profiles above the rooftop level showed a similar exponential decay compared to the profiles measured inside the street canyon. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. 3D Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2010-01-01

    concrete channel with width of 0.8m and a water depth of approximately 0.8m and in circular flume experiments in order to reproduce near-bed specific processes such as resuspension and consolidation. With a fairly good agreement with measurements, modelling of hydrodynamics, transport of dissolved...... pollutants and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  6. Numerical simulation of sediment deposition thickness at Beidaihe International Yacht Club

    Directory of Open Access Journals (Sweden)

    Cheng-gang Lu

    2010-09-01

    Full Text Available The finite element method (FEM was used to simulate sediment hydrodynamics at the Beidaihe International Yacht Club, and a two-dimensional model was established. The sediment movement and deposition were analyzed under many tidal conditions in conjunction with the hydrological regime of the Daihe River. The peak value of the sediment deposition thickness appears in the main channel and around the estuary. The sediment deposition thickness is essentially constant and relatively small in the project area. The sediment deposition thickness in the main channel, in the yachting area, and around the hotel is greater than the other areas in the project. Regular excavation and dredging of the channel is the best measure for mitigating the sedimentation.

  7. Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

    Science.gov (United States)

    Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

    2017-01-01

    Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

  8. Assessment of the Efficiency of Sediment Deposition Reduction in the Zengwen River Watershed in Taiwan

    Science.gov (United States)

    Wu, M.; Tan, H. N.; Lo, W. C.; Tsai, C. T.

    2015-12-01

    The river upstream of watersheds in Taiwan is very steep, where soil and rock are often unstable so that the river watershed typically has the attribute of high sand yield and turbid runoff due to the excessive erosion in the heavy rainfall seasons. If flood water overflows the river bank, it would lead to a disaster in low-altitude plains. When flood retards or recesses, fine sediment would deposit. Over recent decades, many landslides arise in the Zengwen river watershed due to climate changes, earthquakes, and typhoons. The rocks and sands triggered by these landslides would move to the river channel through surface runoff, which may induce sediment disasters and also render an impact on the stability and sediment transport of the river channel. The risk of the sediment disaster could be reduced by implementing dredging works. However, because of the nature of the channel, the dredged river sections may have sediment depositions back; thus, causing an impact on flood safety. Therefore, it is necessary to evaluate the effectiveness of dredged works from the perspectives of hydraulic, sediment transport, and flood protection to achieve the objective of both disaster prevention and river bed stability. We applied the physiographic soil erosion-deposition (PSED) model to simulate the sediment yield, the runoff, and sediment transport rate of the Zengwen river watershed corresponding to one-day rainstorms of the return periods of 25, 50, and 100 year. The potential of sediment deposition and erosion in the river sections of the Zengwen river could be simulated by utilizing the alluvial river-movable bed two dimensional (ARMB-2D) model. The results reveal that the tendency for the potential of river sediment deposition and erosion obtained from these two models is agreeable. Furthermore, in order to evaluate the efficiency of sediment deposition reduction, two quantized values, the rate of sediment deposition reduction and the ratio of sediment deposition reduction

  9. Formation of banded vegetation patterns resulted from interactions between sediment deposition and vegetation growth.

    Science.gov (United States)

    Huang, Tousheng; Zhang, Huayong; Dai, Liming; Cong, Xuebing; Ma, Shengnan

    2018-03-01

    This research investigates the formation of banded vegetation patterns on hillslopes affected by interactions between sediment deposition and vegetation growth. The following two perspectives in the formation of these patterns are taken into consideration: (a) increased sediment deposition from plant interception, and (b) reduced plant biomass caused by sediment accumulation. A spatial model is proposed to describe how the interactions between sediment deposition and vegetation growth promote self-organization of banded vegetation patterns. Based on theoretical and numerical analyses of the proposed spatial model, vegetation bands can result from a Turing instability mechanism. The banded vegetation patterns obtained in this research resemble patterns reported in the literature. Moreover, measured by sediment dynamics, the variation of hillslope landform can be described. The model predicts how treads on hillslopes evolve with the banded patterns. Thus, we provide a quantitative interpretation for coevolution of vegetation patterns and landforms under effects of sediment redistribution. Copyright © 2018. Published by Elsevier Masson SAS.

  10. Direct sampling during multiple sediment density flows reveals dynamic sediment transport and depositional environment in Monterey submarine canyon

    Science.gov (United States)

    Maier, K. L.; Gales, J. A.; Paull, C. K.; Gwiazda, R.; Rosenberger, K. J.; McGann, M.; Lundsten, E. M.; Anderson, K.; Talling, P.; Xu, J.; Parsons, D. R.; Barry, J.; Simmons, S.; Clare, M. A.; Carvajal, C.; Wolfson-Schwehr, M.; Sumner, E.; Cartigny, M.

    2017-12-01

    Sediment density flows were directly sampled with a coupled sediment trap-ADCP-instrument mooring array to evaluate the character and frequency of turbidity current events through Monterey Canyon, offshore California. This novel experiment aimed to provide links between globally significant sediment density flow processes and their resulting deposits. Eight to ten Anderson sediment traps were repeatedly deployed at 10 to 300 meters above the seafloor on six moorings anchored at 290 to 1850 meters water depth in the Monterey Canyon axial channel during 6-month deployments (October 2015 - April 2017). Anderson sediment traps include a funnel and intervalometer (discs released at set time intervals) above a meter-long tube, which preserves fine-scale stratigraphy and chronology. Photographs, multi-sensor logs, CT scans, and grain size analyses reveal layers from multiple sediment density flow events that carried sediment ranging from fine sand to granules. More sediment accumulation from sediment density flows, and from between flows, occurred in the upper canyon ( 300 - 800 m water depth) compared to the lower canyon ( 1300 - 1850 m water depth). Sediment accumulated in the traps during sediment density flows is sandy and becomes finer down-canyon. In the lower canyon where sediment directly sampled from density flows are clearly distinguished within the trap tubes, sands have sharp basal contacts, normal grading, and muddy tops that exhibit late-stage pulses. In at least two of the sediment density flows, the simultaneous low velocity and high backscatter measured by the ADCPs suggest that the trap only captured the collapsing end of a sediment density flow event. In the upper canyon, accumulation between sediment density flow events is twice as fast compared to the lower canyon; it is characterized by sub-cm-scale layers in muddy sediment that appear to have accumulated with daily to sub-daily frequency, likely related to known internal tidal dynamics also measured

  11. Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

    Science.gov (United States)

    Mestdagh, Sebastiaan; Bagaço, Leila; Braeckman, Ulrike; Ysebaert, Tom; De Smet, Bart; Moens, Tom; Van Colen, Carl

    2018-05-01

    Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater-bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the

  12. Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

    Directory of Open Access Journals (Sweden)

    S. Mestdagh

    2018-05-01

    Full Text Available Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC. An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands. The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater–bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our

  13. Sedimentation rates in eastern North America reveal strong links between regional climate, depositional environments, and sediment accumulation

    Science.gov (United States)

    Goring, S. J.; McLachlan, J. S.; Jackson, S. T.; Blaauw, M.; Christen, J.; Marlon, J.; Blois, J.; Williams, J. W.

    2011-12-01

    PalEON is a multidisciplinary project that combines paleo and modern ecological data with state-of-the-art statistical and modelling tools to examine the interactions between climate, fire and vegetation during the past two millennia in the northeastern United States. A fundamental challenge for PalEON (and paleo research more broadly) is to improve age modelling to yield more accurate sediment-core chronologies. To address this challenge, we assessed sedimentation rates and their controls for 218 lakes and mires in the northeastern U.S. Sedimentation rates (yr/cm) were calculated from age-depth models, which were obtained from the Neotoma database (www.neotomadb.org) and other contributed pollen records. The age models were recalibrated to IntCal09 and augmented in some cases using biostratigraphic markers (Picea decline, 16 kcal BP - 10.5 kcal BP; Quercus rise, 12 - 9.1 kcal BP; and Alnus decline, 11.5 - 10.6 kcal BP) as described in Blois et al. (2011). Relationships between sedimentation rates and sediment age, site longitude, and depositional environment (lacustrine or mire) are significant but weak. There are clear and significant links between variations in the NGRIP record of δ18O and sedimentation in mires across the PalEON region, but no links to lacustrine sedimentation rates. This result indicates that super-regional climatic control of primary productivity, and thus autochthonic sediment deposition, dominates in mires while deposition in lacustrine basins may be driven primarily by local and regional factors including watershed size, surficial materials,and regional vegetation. The shape of the gamma probability functions that best describe sedimentation rate distributions are calculated and presented here for use as priors in Bayesian age modelling applications such as BACON (Blaauw and Christen, in press). Future applications of this research are also discussed.

  14. Kinematics of flow and sediment particles at entrainment and deposition

    Science.gov (United States)

    Antico, Federica; Sanches, Pedro; Aleixo, Rui; Ferreira, Rui M. L.

    2015-04-01

    A cohesionless granular bed subjected to a turbulent open-channel flow is analysed. The key objective is to clarify the kinematics of entrainment and deposition of individual sediment particles. In particular, we quantify a) the turbulent flow field in the vicinity of particles at the instants of their entrainment and of their deposition; b) the initial particle velocity and the particle velocity immediately before returning to rest. The experimental work was performed at the Hydraulics Laboratory of IST-UL in a 12.5 m long, 0.405 m wide glass-walled flume recirculating water and sediment through independent circuits. The granular bed was a 4.0 m long and 2.5 cm deep reach filled with 5 mm diameter glass beads packed (with some vibration) to a void fraction of 0.356, typical of random packing. Upstream the mobile bed reach the bed was composed of glued particles to ensure the development of a boundary layer with the same roughness. Laboratory tests were run under conditions of weak beadload transport with Shields parameters in the range 0.007 to 0.03. Froude numbers ranged from 0.63 to 0.95 while boundary Reynolds numbers were in the range 130 to 300. It was observed that the bed featured patches of regular arrangements: face centered cubic (fcc) or hexagonal close packing (hcp) blocks alternate with and body centered cubic (bcc) blocks. The resulting bed surface exhibits cleavage lines between blocks and there are spatial variations of bed elevation. The option for artificial sediment allowed for a simplified description of particle positioning at the instant of entrainment. In particular support and pivoting angles are found analytically. Skin friction angles were determind experimentally. The only relevant variables are exposure (defined as the ratio of the actual frontal projection of the exposed area to the area of a circle with 5 mm diameter) and protrusion (defined as the vertical distance between the apex of the particle and the mean local bed elevation

  15. Impact of beaver ponds on river discharge and sediment deposition along the Chevral River, Ardennes, Belgium

    Science.gov (United States)

    Nyssen, Jan; Frankl, Amaury; Pontzeele, Jolien; De Visscher, Maarten; Billi, Paolo

    2013-04-01

    With the recovery of the European beaver (Castor fiber) and their capacity to engineer fluvial landscapes, questions arise as to how they influence river discharge and sediment transport. The Chevral river (Ardennes, Belgium) contains two beaver dam sequences which appeared in 2004 and count now about 30 dams. Flow discharges and sediment fluxes were measured at the in- and outflow of each dam sequence. Volumes of sediment deposited behind the dams were measured. Between 2004 and 2011, peak flows were topped off, and the magnitude of extreme events decreased. 1710 m³ of sediment were deposited behind the beaver dams, with an average sediment thickness of 25 cm. The thickness of the sediment layer is related to the area of the beaver ponds. Along the stream, beaver pond sediment thickness displayed a sinusoidal deposition pattern, in which ponds with thick sediment layers were preceded by a series of ponds with thinner sediment layers. A downstream textural coarsening in the dam sequences was also observed, probably due to dam failures subsequent to surges. Differences in sediment flux between the in- and outflow at the beaver pond sequence were related to the river hydrograph, with deposition taking place during the rising limbs and slight erosion during the falling limbs. The seven-year-old sequences have filtered 190 tons of sediment out of the Chevral river, which is of the same order of magnitude as the 374 tons measured in pond deposits, with the difference between the values corresponding to beaver excavations (60 tons), inflow from small tributaries, and runoff from the valley flanks. Hydrogeomorphic effects of C. fiber and C. canadensis activity are similar in magnitude. The detailed analysis of changes to hydrology in beaver pond sequences confirms the potential of beavers to contribute to river and wetland restoration and catchment management.

  16. Sedimentation rates and depositional processes in Lake Superior from 210Pb geochronology

    International Nuclear Information System (INIS)

    Evans, J.E.; Johnson, T.C.; Alexander, E.C. Jr.; Lively, R.S.; Eisenreich, S.J.

    1981-01-01

    Sedimentation rates range from 0.01 to 0.32 cm/yr in 17 sediment box cores from Lake Superior, as determined by 210 Pb geochronology. Shoreline erosion and resuspension of nearshore sediments causes moderate to high (0.05-0.11 cm/yr) sedimentation rates in the western arm of Lake Superior. Sedimentation rates are very high (> 0.15 cm/yr) in marginal bays adjoining Lake Superior; and moderate to very high (0.07-0.19 cm/yr) in open lake regions adjacent to marginal bays. Resuspension of nearshore and shoal top sediments in southern and southeastern Lake Superior by storms is responsible for depositional anomalies in 210 Pb profiles corresponding to 1905, 1916-1918, and 1940 storms. Sedimentation rates are very low (0.01-0.03 cm/yr) in the central basins due to isolation from sediment sources. These data indicate that sedimentation rates and processes vary significantly in different regions of Lake Superior. The sedimentation rates provided by this study, in conjunction with previously-reported sedimentation rates, yield a better understanding of the Lake Superior depositional environment

  17. Environmental and geochemical assessment of surface sediments on irshansk ilmenite deposit area

    Directory of Open Access Journals (Sweden)

    Наталия Олеговна Крюченко

    2015-03-01

    Full Text Available It is revealed the problem of pollution of surface sediments of Irshansk ilmenite deposit area of various chemical elements hazard class (Mn, V, Ba, Ni, Co, Cr, Mo, Cu, Pb, Zn. It is determined its average content in surface sediments of various functional areas (forest and agricultural land, flood deposits, reclaimed land, calculated geochemical criteria, so given ecological and geochemical assessment of area

  18. Bioassessment metrics and deposited sediments in tributaries of the Chattooga river watershed

    Science.gov (United States)

    Erica Chiao; J. Bruce Wallace

    2003-01-01

    Excessive sedimentation places waters of the Chattooga River network at risk of biological impairment. Monitoring efforts could be improved by including metrics that are responsive to changes in levels of fine sediments. We sampled three habitats (riffle, depositional, bedrock outcrop) for benthic macroinvertebrates at four sites in three low-order, tributary reaches...

  19. Evaluation of suspended sediment concentrations, sediment fluxes and sediment depositions along a reservoir by using laser diffraction and acoustic backscatter data

    Science.gov (United States)

    Lizano, Laura; Haun, Stefan

    2015-04-01

    The construction of dams and reservoirs disturb the natural morphological behavior of rivers. A natural settling effect occurs due to the reduced turbulences and flow velocities. As a consequence, reservoirs fill up with sediments which results in a reduction of storage volume, influences the operation of hydropower plants and leads in several cases to flood protection problems. The sediment depositions in reservoirs are standardly evaluated by using bathymetric data, obtained by a single beam sonar from pre-defined cross sections or by an extensive evaluation of the reservoir bed by a side scan sonar. However, a disadvantage of this method is that it is not possible to evaluate the pore water content of the depositions, which may lead as consequence to an uncertainty in the measured amount of deposited sediments. Given that a major part of sediments entering reservoirs are transported in suspension, sediment flux measurements along defined transects could give more reliable information on the settled amount of sediments and additional information on the sediment transport mechanism within the reservoir. An evaluation of the sediment fluxes is in practice often conducted by a single suspended sediment concentration (SSC) measurement in combination with a cross sectional calibration factor to take changes in the SSC along the transect into account. However, these calibration factors are often developed only for one specific in-situ condition and may give unreliable results in case that the boundaries change e.g. the hydraulic conditions. Hence an evaluation of the sediment fluxes along the whole transect would give a more reliable number for the amount of transported sediments through the reservoir. This information can afterwards be used to calculate the amount of settled sediments in different sections of the reservoir and the amount of sediments which will enter the intake. For this study the suspended sediment transport within the Peñas Blancas reservoir in

  20. Formation of fine sediment deposit from a flash flood river in the Mediterranean Sea

    Science.gov (United States)

    Grifoll, Manel; Gracia, Vicenç; Aretxabaleta, Alfredo L.; Guillén, Jorge; Espino, Manuel; Warner, John C.

    2014-01-01

    We identify the mechanisms controlling fine deposits on the inner-shelf in front of the Besòs River, in the northwestern Mediterranean Sea. This river is characterized by a flash flood regime discharging large amounts of water (more than 20 times the mean water discharge) and sediment in very short periods lasting from hours to few days. Numerical model output was compared with bottom sediment observations and used to characterize the multiple spatial and temporal scales involved in offshore sediment deposit formation. A high-resolution (50 m grid size) coupled hydrodynamic-wave-sediment transport model was applied to the initial stages of the sediment dispersal after a storm-related flood event. After the flood, sediment accumulation was predominantly confined to an area near the coastline as a result of preferential deposition during the final stage of the storm. Subsequent reworking occurred due to wave-induced bottom shear stress that resuspended fine materials, with seaward flow exporting them toward the midshelf. Wave characteristics, sediment availability, and shelf circulation determined the transport after the reworking and the final sediment deposition location. One year simulations of the regional area revealed a prevalent southwestward average flow with increased intensity downstream. The circulation pattern was consistent with the observed fine deposit depocenter being shifted southward from the river mouth. At the southern edge, bathymetry controlled the fine deposition by inducing near-bottom flow convergence enhancing bottom shear stress. According to the short-term and long-term analyses, a seasonal pattern in the fine deposit formation is expected.

  1. Morphological resilience to flow fluctuations of fine sediment deposits in bank lateral cavities

    Science.gov (United States)

    Juez, C.; Thalmann, M.; Schleiss, A. J.; Franca, M. J.

    2018-05-01

    Lateral cavities are built in the banks of rivers for several purposes: to create harbors, to capture sediment, to keep a central navigable channel (i.e., Casiers de Girardon in the Rhone river) or to promote the formation of aquatic habitats if a limited amount of sediment is captured, providing hydraulic and morphologic diversity (i.e., the case of Japanese Wandos). This work is focused on this latter purpose: promotion of hydraulic and morphologic diversity. In these scenarios, an increase in the flow discharge in the main channel may, however, re-mobilize the deposit of sediment inside these lateral embayments and cause a sudden increase of the sediment concentration and turbidity in the main channel. It is thus of interest to characterize the resistance and resilience of these sedimentary deposits when the main channel is subjected to high flow or flushing events. Laboratory tests were carried out for five different normalized geometries of the cavities installed in the banks of an open channel and for five hydrographs with different levels of unsteadiness. Water depth, sediment deposit mass, sediment concentration and area covered by the settled sediments were recorded throughout each experiment. Although sediment deposits established at equilibrium before the flushing events are different depending on the geometry of the cavities, generally, they are recovered after being flushed by the high flow events. It is shown that the resistance and resilience of the sediment deposits are strongly dependent on the flow field and the mass exchange between the main channel and the cavities. This mass exchange is governed by the geometry of the cavities and the magnitude of the hydrographs applied.

  2. Numerical simulation of sediment movement and deposition in a meandering channel

    International Nuclear Information System (INIS)

    Ghani, U.

    2011-01-01

    In this research work, predictions have been made for the transport and deposition of incoming sediments in an open channel. Attempt has been made to understand the behavior of sediments flowing in the channel. The geometry consisted of a meandering compound channel with a constant inflow of sediments. For this purpose, 3D version of CFD (Computational Fluid Dynamics) code FLUENT has been used as a research tool. The turbulence closure of Reynolds Averaged Navior-Stokes equation was performed with standard -turbulence model. The Lagrangian particle tracking technique available in the code has been used for modeling sediment movement and deposition. For this purpose, nine different ranges of the particle diameters were released at the inlet of the channel. Initially, the model was validated using point velocities in the downstream direction and discharge values at five cross sections along the meander wavelength. The channel used for simulation purposes had a rectangular section. Once the model validated, it was then used for simulation of sediments. The numerical modeling gave a detailed picture of sediment deposited and transported through the channel. As the model was used with - turbulence model and Lagrangian particle tracking technique and then validated, it showed that when this combination of particle tracking and turbulence closure option will be used, the prediction will be fairly good and trustworthy. A number of numerical experiments were conducted to get the impact of sediment inflow velocity and its diameter on deposition patterns. It showed that boundary shearing stresses and secondary flows had considerable impact on sediment deposition in a river bend. The current study revealed that CFD technique can be used for predicting sediment distribution patterns with reasonable confidence. Such prediction techniques are not only economical but also provide details of complex flow and sediment movement behavior which are difficult to get through

  3. Cumulative history recorded in the depth distribution of radiocesium in sediments deposited on a sandbar

    International Nuclear Information System (INIS)

    Tanaka, Kazuya; Kondo, Hiroaki; Sakaguchi, Aya; Takahashi, Yoshio

    2015-01-01

    We collected sediments deposited on a sandbar from the surface to 20 cm in depth in the Abukuma River to clarify the history of radiocesium derived from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. We analyzed the "1"3"7Cs concentration in the sediments from size-fractioned samples as well as bulk samples. The depth distribution of "1"3"7Cs showed the highest concentration in the deepest sediment layer (18–20 cm) studied, which indicates that sediments with a lower "1"3"7Cs concentration were transported and deposited on sediments having a higher "1"3"7Cs concentration. At the same time, the depth distribution suggests a decrease in radioactivity in provenance areas of the sediments. Analysis of the size-fractioned sediments indicated that the three sediment layers at 4–6 cm, 16–18 cm and 18–20 cm intervals had similar size distribution of "1"3"7Cs and grain size composition although the concentration levels of "1"3"7Cs were different according to their bulk concentrations. The size distribution of "1"3"7Cs also supported the possibility that the decrease in "1"3"7Cs concentration in bulk sediments above 18 cm is due to a decrease in the level of radioactivity in the catchment area. A comparison of the size distribution of "1"3"7Cs between the sediment layers above and below 18 cm suggested that the "1"3"7Cs concentration in the transported fine sediment particles decreased more with time than the "1"3"7Cs concentration in the coarse particles, reflecting the selective transport of the finer particles. The results of this study demonstrated that sediment layers deposited on a sandbar retained the cumulative history of the fluvial transport of radiocesium after the FDNPP accident. - Highlights: • We investigated the history of "1"3"7Cs recorded in sediments in the Abukuma River. • "1"3"7Cs concentration was the highest in the deepest sediment layer studied. • The depth distribution suggests a decrease in radioactivity in

  4. Morphodynamic simulation of sediment deposition patterns on a recently stripped bedrock anastomosed channel

    Directory of Open Access Journals (Sweden)

    D. Milan

    2018-04-01

    Full Text Available Some mixed bedrock-alluvial dryland rivers are known to undergo cycles of alluvial building during low flow periods, punctuated by stripping events during rare high magnitude flows. We focus on the Olifants River, Kruger National Park, South Africa, and present 2-D morphodynamic simulations of hydraulics and sediment deposition patterns over an exposed bedrock anastomosed pavement. We examine the assumptions underlying a previous conceptual model, namely that sedimentation occurs preferentially on bedrock highs. Our modelling results and local field observations in fact show that sediment thicknesses are greater over bedrock lows, suggesting these are the key loci for deposition, barform initiation and island building. During peak flows, velocities in the topographic lows tend to be lower than in intermediate topographic areas. It is likely that intermediate topographic areas supply sediment to the topographic lows at this flow stage, which is then deposited in the lows on the falling limb of the hydrograph as velocities reduce. Subsequent vegetation establishment on deposits in the topographic lows is likely to play a key role in additional sedimentation and vegetation succession, both through increasing the cohesive strength of alluvial units and by capturing new sediments and propagules.

  5. Morphodynamic simulation of sediment deposition patterns on a recently stripped bedrock anastomosed channel

    Science.gov (United States)

    Milan, David; Heritage, George; Entwistle, Neil; Tooth, Stephen

    2018-04-01

    Some mixed bedrock-alluvial dryland rivers are known to undergo cycles of alluvial building during low flow periods, punctuated by stripping events during rare high magnitude flows. We focus on the Olifants River, Kruger National Park, South Africa, and present 2-D morphodynamic simulations of hydraulics and sediment deposition patterns over an exposed bedrock anastomosed pavement. We examine the assumptions underlying a previous conceptual model, namely that sedimentation occurs preferentially on bedrock highs. Our modelling results and local field observations in fact show that sediment thicknesses are greater over bedrock lows, suggesting these are the key loci for deposition, barform initiation and island building. During peak flows, velocities in the topographic lows tend to be lower than in intermediate topographic areas. It is likely that intermediate topographic areas supply sediment to the topographic lows at this flow stage, which is then deposited in the lows on the falling limb of the hydrograph as velocities reduce. Subsequent vegetation establishment on deposits in the topographic lows is likely to play a key role in additional sedimentation and vegetation succession, both through increasing the cohesive strength of alluvial units and by capturing new sediments and propagules.

  6. Observations of Lower Mississippi River Estuarine Dynamics: Effects of the Salt Wedge on Sediment Deposition

    Science.gov (United States)

    Ramirez, M. T.; Allison, M. A.

    2017-12-01

    The lowermost Mississippi River is subject to salt-wedge estuarine conditions during seasonally low flow, when seaward flow is unable to overcome density stratification. Previous studies in the Mississippi River salt wedge have shown the deposition of a fine sediment layer accumulating several mm/day beneath the reach where the salt wedge is present. Field studies were conducted during low flow in 2012-2015 utilizing ADCP, CTD, LISST, and physical samples to observe the physics of the salt wedge reach and to calculate rates and character of sediment trapping beneath the salt wedge. The field observations were summarized using a two-layer box-model representation of the reach to calculate water and sediment budgets entering, exiting, and stored within the reach. The salt wedge reach was found to be net depositional at rates up to 1.8 mm/day. The mechanism for transferring sediment mass from the downstream-flowing fluvial layer to the upstream-flowing marine layer appears to be flocculation, evidenced in LISST data by a spike in sediment particle diameters at the halocline. Applying reach-averaged rates of sediment trapping to a time-integrated model of salt-wedge position, we calculated annual totals ranging from 0.025 to 2.2 million tons of sediment deposited beneath the salt wedge, depending on salt-wedge persistence and upstream extent. Most years this seasonal deposit is remobilized during spring flood following the low-flow estuarine season, which may affect the timing of sediment delivery to the Gulf of Mexico, as well as particulate organic carbon, whose transport trajectory mirrors that of mineral sediment. These results are also relevant to ongoing dredging efforts necessary to maintain the economically-important navigation pathway through the lower Mississippi River, as well as planned efforts to use Mississippi River sedimentary resources to build land in the degrading Louisiana deltaic coast.

  7. How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments?

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@rmit.edu.a [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Zalizniak, Liliana [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Dunlop, Jason E. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia); Smart Water Research Facility, Griffith University, Queensland (Australia); Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Choy, Satish C. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia)

    2010-02-15

    The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000-1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1-5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. - Sediment deposition may be more directly detrimental to macroinvertebrates of lowland rivers than suspended sediments.

  8. Sediment-hosted gold deposits of the world: database and grade and tonnage models

    Science.gov (United States)

    Berger, Vladimir I.; Mosier, Dan L.; Bliss, James D.; Moring, Barry C.

    2014-01-01

    All sediment-hosted gold deposits (as a single population) share one characteristic—they all have disseminated micron-sized invisible gold in sedimentary rocks. Sediment-hosted gold deposits are recognized in the Great Basin province of the western United States and in China along with a few recognized deposits in Indonesia, Iran, and Malaysia. Three new grade and tonnage models for sediment-hosted gold deposits are presented in this paper: (1) a general sediment-hosted gold type model, (2) a Carlin subtype model, and (3) a Chinese subtype model. These models are based on grade and tonnage data from a database compilation of 118 sediment-hosted gold deposits including a total of 123 global deposits. The new general grade and tonnage model for sediment-hosted gold deposits (n=118) has a median tonnage of 5.7 million metric tonnes (Mt) and a gold grade of 2.9 grams per tonne (g/t). This new grade and tonnage model is remarkable in that the estimated parameters of the resulting grade and tonnage distributions are comparable to the previous model of Mosier and others (1992). A notable change is in the reporting of silver in more than 10 percent of deposits; moreover, the previous model had not considered deposits in China. From this general grade and tonnage model, two significantly different subtypes of sediment-hosted gold deposits are differentiated: Carlin and Chinese. The Carlin subtype includes 88 deposits in the western United States, Indonesia, Iran, and Malaysia, with median tonnage and grade of 7.1 Mt and 2.0 g/t Au, respectively. The silver grade is 0.78 g/t Ag for the 10th percentile of deposits. The Chinese subtype represents 30 deposits in China, with a median tonnage of 3.9 Mt and medium grade of 4.6 g/t Au. Important differences are recognized in the mineralogy and alteration of the two sediment-hosted gold subtypes such as: increased sulfide minerals in the Chinese subtype and decalcification alteration dominant in the Carlin type. We therefore

  9. Evolution of radioactive dose rates in fresh sediment deposits along coastal rivers draining Fukushima contamination plume

    OpenAIRE

    Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Patin, Jeremy; Lepage, Hugo; Lef?vre, Ir?ne; Ayrault, Sophie; Ottl?, Catherine; Bont?, Philippe

    2013-01-01

    Measurement of radioactive dose rates in fine sediment that has recently deposited on channel bed-sand provides a solution to address the lack of continuous river monitoring in Fukushima Prefecture after Fukushima Dai-ichi nuclear power plant (FDNPP) accident. We show that coastal rivers of Eastern Fukushima Prefecture were rapidly supplied with sediment contaminated by radionuclides originating from inland mountain ranges, and that this contaminated material was partly exported by typhoons t...

  10. Sediment depositions upstream of open check dams: new elements from small scale models

    Science.gov (United States)

    Piton, Guillaume; Le Guern, Jules; Carbonari, Costanza; Recking, Alain

    2015-04-01

    Torrent hazard mitigation remains a big issue in mountainous regions. In steep slope streams and especially in their fan part, torrential floods mainly result from abrupt and massive sediment deposits. To curtail such phenomenon, soil conservation measures as well as torrent control works have been undertaken for decades. Since the 1950s, open check dams complete other structural and non-structural measures in watershed scale mitigation plans1. They are often built to trap sediments near the fan apexes. The development of earthmoving machinery after the WWII facilitated the dredging operations of open check dams. Hundreds of these structures have thus been built for 60 years. Their design evolved with the improving comprehension of torrential hydraulics and sediment transport; however this kind of structure has a general tendency to trap most of the sediments supplied by the headwaters. Secondary effects as channel incision downstream of the traps often followed an open check dam creation. This sediment starvation trend tends to propagate to the main valley rivers and to disrupt past geomorphic equilibriums. Taking it into account and to diminish useless dredging operation, a better selectivity of sediment trapping must be sought in open check dams, i.e. optimal open check dams would trap sediments during dangerous floods and flush them during normal small floods. An accurate description of the hydraulic and deposition processes that occur in sediment traps is needed to optimize existing structures and to design best-adjusted new structures. A literature review2 showed that if design criteria exist for the structure itself, little information is available on the dynamic of the sediment depositions upstream of open check dams, i.e. what are the geomorphic patterns that occur during the deposition?, what are the relevant friction laws and sediment transport formula that better describe massive depositions in sediment traps?, what are the range of Froude and Shields

  11. Sediment-Hosted Zinc-Lead Deposits of the World - Database and Grade and Tonnage Models

    Science.gov (United States)

    Singer, Donald A.; Berger, Vladimir I.; Moring, Barry C.

    2009-01-01

    This report provides information on sediment-hosted zinc-lead mineral deposits based on the geologic settings that are observed on regional geologic maps. The foundation of mineral-deposit models is information about known deposits. The purpose of this publication is to make this kind of information available in digital form for sediment-hosted zinc-lead deposits. Mineral-deposit models are important in exploration planning and quantitative resource assessments: Grades and tonnages among deposit types are significantly different, and many types occur in different geologic settings that can be identified from geologic maps. Mineral-deposit models are the keystone in combining the diverse geoscience information on geology, mineral occurrences, geophysics, and geochemistry used in resource assessments and mineral exploration. Too few thoroughly explored mineral deposits are available in most local areas for reliable identification of the important geoscience variables, or for robust estimation of undiscovered deposits - thus, we need mineral-deposit models. Globally based deposit models allow recognition of important features because the global models demonstrate how common different features are. Well-designed and -constructed deposit models allow geologists to know from observed geologic environments the possible mineral-deposit types that might exist, and allow economists to determine the possible economic viability of these resources in the region. Thus, mineral-deposit models play the central role in transforming geoscience information to a form useful to policy makers. This publication contains a computer file of information on sediment-hosted zinc-lead deposits from around the world. It also presents new grade and tonnage models for nine types of these deposits and a file allowing locations of all deposits to be plotted in Google Earth. The data are presented in FileMaker Pro, Excel and text files to make the information available to as many as possible. The

  12. Depositional environment of near-surface sediments, King George Basin, Bransfield Strait, Antarctica

    Science.gov (United States)

    Yoon, H. I.; Park, B. K.; Chang, S. K.; Han, M. W.; Oh, J. K.

    1994-03-01

    Four sediment cores were collected to determine the depositional environments of the King George Basin northeast of Bransfield Strait, Antarctica. The cored section revealed three distinct lithofacies: laminated siliceous ooze derived from an increased paleoproductivity near the receding sea-ice edges, massive muds that resulted from hemipelagic sedimentation in open water, and graded sediments that originated from nearby local seamounts by turbidity currents. Clay mineral data of the cores indicate a decreasing importance of volcanic activity through time. Active volcanism and hydrothermal activity appear to be responsible for the enrichment of smectite near the Penguin and Bridgeman Islands.

  13. An acoustic method for predicting relative strengths of cohesive sediment deposits

    Science.gov (United States)

    Reed, A. H.; Sanders, W. M.

    2017-12-01

    Cohesive sediment dynamics are fundamentally determined by sediment mineralogy, organic matter composition, ionic strength of water, and currents. These factors work to bind the cohesive sediments and to determine depositional rates. Once deposited the sediments exhibit a nonlinear response to stress and they develop increases in shear strength. Shear strength is critically important in resuspension, transport, creep, and failure predictions. Typically, shear strength is determined by point measurements, both indirectly from free-fall penetrometers or directly on cores with a shear vane. These values are then used to interpolate over larger areas. However, the remote determination of these properties would provide continuos coverage, yet it has proven difficult with sonar systems. Recently, findings from an acoustic study on cohesive sediments in a laboratory setting suggests that cohesive sediments may be differentiated using parametric acoustics; this method pulses two primary frequencies into the sediment and the resultant difference frequency is used to determine the degree of acoustic nonlinearity within the sediment. In this study, two marine clay species, kaolinite and montmorillonite, and two biopolymers, guar gum and xanthan gum were mixed to make nine different samples. The samples were evaluated in a parametric acoustic measurement tank. From the parametric acoustic measurements, the quadratic nonlinearity coefficient (beta) was determined. beta was correlated with the cation exchange capacity (CEC), an indicator of shear strength. The results indicate that increased acoustic nonlinearity correlates with increased CEC. From this work, laboratory measurements indicate that this correlation may be used evaluate geotechnical properties of cohesive sediments and may provide a means to predict sediment weakness in subaqueous environments.

  14. Spatial and temporal variability in sedimentation rates associated with cutoff channel infill deposits: Ain River, France

    Science.gov (United States)

    Piégay, H.; Hupp, C.R.; Citterio, A.; Dufour, S.; Moulin, B.; Walling, D.E.

    2008-01-01

    Floodplain development is associated with lateral accretion along stable channel geometry. Along shifting rivers, the floodplain sedimentation is more complex because of changes in channel position but also cutoff channel presence, which exhibit specific overflow patterns. In this contribution, the spatial and temporal variability of sedimentation rates in cutoff channel infill deposits is related to channel changes of a shifting gravel bed river (Ain River, France). The sedimentation rates estimated from dendrogeomorphic analysis are compared between and within 14 cutoff channel infills. Detailed analyses along a single channel infill are performed to assess changes in the sedimentation rates through time by analyzing activity profiles of the fallout radionuclides 137Cs and unsupported 210Pb. Sedimentation rates are also compared within the channel infills with rates in other plots located in the adjacent floodplain. Sedimentation rates range between 0.65 and 2.4 cm a−1 over a period of 10 to 40 years. The data provide additional information on the role of distance from the bank, overbank flow frequency, and channel geometry in controlling the sedimentation rate. Channel infills, lower than adjacent floodplains, exhibit higher sedimentation rates and convey overbank sediment farther away within the floodplain. Additionally, channel degradation, aggradation, and bank erosion, which reduce or increase the distance between the main channel and the cutoff channel aquatic zone, affect local overbank flow magnitude and frequency and therefore sedimentation rates, thereby creating a complex mosaic of sedimentation zones within the floodplain and along the cutoff channel infills. Last, the dendrogeomorphic and 137Cs approaches are cross validated for estimating the sedimentation rate within a channel infill.

  15. Design of a fuzzy differential evolution algorithm to predict non-deposition sediment transport

    Science.gov (United States)

    Ebtehaj, Isa; Bonakdari, Hossein

    2017-12-01

    Since the flow entering a sewer contains solid matter, deposition at the bottom of the channel is inevitable. It is difficult to understand the complex, three-dimensional mechanism of sediment transport in sewer pipelines. Therefore, a method to estimate the limiting velocity is necessary for optimal designs. Due to the inability of gradient-based algorithms to train Adaptive Neuro-Fuzzy Inference Systems (ANFIS) for non-deposition sediment transport prediction, a new hybrid ANFIS method based on a differential evolutionary algorithm (ANFIS-DE) is developed. The training and testing performance of ANFIS-DE is evaluated using a wide range of dimensionless parameters gathered from the literature. The input combination used to estimate the densimetric Froude number ( Fr) parameters includes the volumetric sediment concentration ( C V ), ratio of median particle diameter to hydraulic radius ( d/R), ratio of median particle diameter to pipe diameter ( d/D) and overall friction factor of sediment ( λ s ). The testing results are compared with the ANFIS model and regression-based equation results. The ANFIS-DE technique predicted sediment transport at limit of deposition with lower root mean square error (RMSE = 0.323) and mean absolute percentage of error (MAPE = 0.065) and higher accuracy ( R 2 = 0.965) than the ANFIS model and regression-based equations.

  16. Reconstructing Sediment Supply, Transport and Deposition Behind the Elwha River Dams

    Science.gov (United States)

    Beveridge, C.

    2017-12-01

    The Elwha River watershed in Olympic National Park of Washington State, USA is predominantly a steep, mountainous landscape where dominant geomorphic processes include landslides, debris flows and gullying. The river is characterized by substantial variability of channel morphology and fluvial processes, and alternates between narrow bedrock canyons and wider alluvial reaches for much of its length. Literature suggests that the Elwha watershed is topographically and tectonically in steady state. The removal of the two massive hydropower dams along the river in 2013 marked the largest dam removal in history. Over the century long lifespan of the dams, approximately 21 million cubic meters of sediment was impounded behind them. Long term erosion rates documented in this region and reservoir sedimentation data give unprecedented opportunities to test watershed sediment yield models and examine dominant processes that control sediment yield over human time scales. In this study, we aim to reconstruct sediment supply, transport and deposition behind the Glines Canyon Dam (most upstream dam) over its lifespan using a watershed modeling approach. We developed alternative models of varying complexity for sediment production and transport at the network scale driven by hydrologic forcing. We simulate sediment supply and transport in tributaries upstream of the dam. The modeled sediment supply and transport dynamics are based on calibrated formulae (e.g., bedload transport is simulated using Wilcock-Crowe 2003 with modification based on observed bedload transport in the Elwha River). Observational data that aid in our approach include DEM, channel morphology, meteorology, and streamflow and sediment (bedload and suspended load) discharge. We aim to demonstrate how the observed sediment yield behind the dams was influenced by upstream transport supply and capacity limitations, thereby demonstrating the scale effects of flow and sediment transport processes in the Elwha River

  17. Tracing contaminant pathways in sandy heterogeneous glaciofluvial sediments using a sedimentary depositional model

    International Nuclear Information System (INIS)

    Webb, E.K.; Anderson, M.P.

    1990-01-01

    Heterogeneous sedimentary deposits present complications for tracking contaminant movement by causing a complex advective flow field. Connected areas of high conductivity produce so-called fast paths that control movement of solutes. Identifying potential fast paths and describing the variation in hydraulic properties was attempted through simulating the deposition of a glaciofluvial deposit (outwash). Glaciofluvial deposits usually consist of several depositional facies, each of which has different physical characteristics, depositional structures and hydraulic properties. Therefore, it is unlikely that the property of stationarity (a constant mean hydraulic conductivity and a mono-modal probability distribution) holds for an entire glaciofluvial sequence. However, the process of dividing an outwash sequence into geologic facies presumably identifies units of material with similar physical characteristics. It is proposed that patterns of geologic facies determined by field observation can be quantified by mathematical simulation of sediment deposition. Subsequently, the simulated sediment distributions can be used to define the distribution of hydrogeologic parameters and locate possible fast paths. To test this hypothesis, a hypothetical glacial outwash deposit based on geologic facies descriptions contained in the literature was simulated using a sedimentary depositional model, SEDSIM, to produce a three-dimensional description of sediment grain size distributions. Grain size distributions were then used to estimate the spatial distribution of hydraulic conductivity. Subsequently a finite-difference flow model and linked particle tracking algorithm were used to trace conservative transport pathways. This represents a first step in describing the spatial heterogeneity of hydrogeologic characteristics for glaciofluvial and other braided stream environments. (Author) (39 refs., 7 figs.)

  18. Earthworms as colonisers: Primary colonisation of contaminated land, and sediment and soil waste deposits

    NARCIS (Netherlands)

    Eijsackers, H.J.P.

    2010-01-01

    This paper reviews the role of earthworms in the early colonisation of contaminated soils as well as sediment and waste deposits, which are worm-free because of anthropogenic activities such as open-cast mining, soil sterilisation, consistent pollution or remediation of contaminated soil. Earthworms

  19. Post-depositional formation of vivianite-type minerals alters sediment phosphorus records

    NARCIS (Netherlands)

    DIjkstra, Nikki; Hagens, Mathilde; Egger, Matthias; Slomp, Caroline P.

    2018-01-01

    Phosphorus (P) concentrations in sediments are frequently used to reconstruct past environmental conditions in freshwater and marine systems, with high values thought to be indicative of a high biological productivity. Recent studies suggest that the post-depositional formation of vivianite, an

  20. Recent sediment transport and deposition in the Nazaré Canyon, Portuguese continental margin.

    NARCIS (Netherlands)

    de Stigter, H.C.; Boer, W.; de Jesus Mendes, P.A.; Jesus, C.C.; Thomsen, L.; van den Bergh, G.D.; van Weering, T.C.E.

    2007-01-01

    Processes, pathways and fluxes of sediment transport and deposition in the Nazaré submarine canyon, Portuguese continental margin, were investigated by water column profiling of suspended particulate matter, recording of near-bottom currents and suspended particulate matter fluxes with benthic

  1. Deposition and Accumulation of Emerging Contaminants in the Sediments of the Palos Verde Shelf, California

    Science.gov (United States)

    Deposition and Accumulation of Emerging Contaminants in the Sediments of the Palos Verde Shelf, California Mark G. Cantwell, David R. Katz, Julia Sullivan, Robert P. Eganhouse, Monique M. Perron, Robert M. Burgess The Palos Verdes shelf is located off the Southern California coa...

  2. Velocity-based analysis of sediment incipient deposition in rigid boundary open channels.

    Science.gov (United States)

    Aksoy, Hafzullah; Safari, Mir Jafar Sadegh; Unal, Necati Erdem; Mohammadi, Mirali

    2017-11-01

    Drainage systems must be designed in a way to minimize undesired problems such as decrease in hydraulic capacity of the channel, blockage and transport of pollutants due to deposition of sediment. Channel design considering self-cleansing criteria are used to solve the sedimentation problem. Incipient deposition is one of the non-deposition self-cleansing design criteria that can be used as a conservative method for channel design. Experimental studies have been carried out in five different cross-section channels, namely trapezoidal, rectangular, circular, U-shape and V-bottom. Experiments were performed in a tilting flume using four different sizes of sands as sediment in nine different channel bed slopes. Two well-known methods, namely the Novak & Nalluri and Yang methods are considered for the analysis of sediment motion. Equations developed using experimental data are found to be in agreement with the literature. It is concluded that the design velocity depends on the shape of the channel cross-section. Rectangular and V-bottom channels need lower and higher incipient deposition velocities, respectively, in comparison with other channels.

  3. Plutonium transport to and deposition and immobility in Irish Sea intertidal sediments

    Energy Technology Data Exchange (ETDEWEB)

    Aston, S R; Stanners, D A [Lancaster Univ. (UK)

    1981-02-12

    The results are presented of an investigation of plutonium in intertidal sediments of the Irish Sea, contaminated with radioactive wastes from the Windscale reprocessing facility. The deposition characteristics and lack of vertical migration of /sup 238/Pu and /sup 239/ and /sup 240/Pu are discussed.

  4. The effect of deposited fine sediment on summer survival and growth of rainbow trout in riffles of a small stream

    Science.gov (United States)

    Bret C. Harvey; Jason L. White; Rodney J. Nakamoto

    2009-01-01

    Elevated fine-sediment inputs to streams can alter a variety of conditions and processes, including the amount of fine sediment stored in riffles. We sought to measure the influence of deposited fine sediment on the survival and growth of juvenile rainbow trout Oncorhynchus mykiss (106–130 mm fork length) using a field experiment that included 18 enclosures in riffles...

  5. Estuarine Sediment Deposition during Wetland Restoration: A GIS and Remote Sensing Modeling Approach

    Science.gov (United States)

    Newcomer, Michelle; Kuss, Amber; Kentron, Tyler; Remar, Alex; Choksi, Vivek; Skiles, J. W.

    2011-01-01

    Restoration of the industrial salt flats in the San Francisco Bay, California is an ongoing wetland rehabilitation project. Remote sensing maps of suspended sediment concentration, and other GIS predictor variables were used to model sediment deposition within these recently restored ponds. Suspended sediment concentrations were calibrated to reflectance values from Landsat TM 5 and ASTER using three statistical techniques -- linear regression, multivariate regression, and an Artificial Neural Network (ANN), to map suspended sediment concentrations. Multivariate and ANN regressions using ASTER proved to be the most accurate methods, yielding r2 values of 0.88 and 0.87, respectively. Predictor variables such as sediment grain size and tidal frequency were used in the Marsh Sedimentation (MARSED) model for predicting deposition rates for three years. MARSED results for a fully restored pond show a root mean square deviation (RMSD) of 66.8 mm (<1) between modeled and field observations. This model was further applied to a pond breached in November 2010 and indicated that the recently breached pond will reach equilibrium levels after 60 months of tidal inundation.

  6. Geochemical partitioning of lead in biogenic carbonate sediments in a coral reef depositional environment

    International Nuclear Information System (INIS)

    Horta-Puga, Guillermo

    2017-01-01

    The fate of trace elements in reef depositional environments has not been extensively investigated. The aim of this study was to determine the partitioning of Pb in sediments of the Veracruz Reef System, and its relation to local environmental sources. Lead was determined in four geochemical fractions: exchangeable (3.8 ± 0.4 μg g −1 ), carbonate (57.0 ± 13.6 μg g −1 ), organic matter (2.0 ± 0.9 μg g −1 ), and mineral (17.5 ± 5.4 μg g −1 ). For the mineral fraction, lead concentrations were higher in those reefs influenced by river discharge or by long-distance transport of terrigenous sediments. The bioavailable concentration of lead (range: 21.9–85.6 μg g −1 ) indicates that the Veracruz Reef System is a moderately polluted area. As expected, the carbonate fraction contained the highest proportion of Pb (70%), and because the reef framework is largely made up of by biogenic carbonate sediments, hence, it is therefore the most important repository of Pb in coral reef depositional environments. - Highlights: • Lead concentrations were determined in four geochemical fractions of reef sediments. • The carbonate fraction accounted for > 70% of the content of Pb in reef sediments. • Terrigenous sediments are the main source of Pb associated to the mineral fraction. • The Veracruz Reef System is considered a moderately polluted area. • Sediments are the main repositories of lead in coral reef depositional environments.

  7. Evolution of radioactive dose rates in fresh sediment deposits along coastal rivers draining Fukushima contamination plume.

    Science.gov (United States)

    Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Patin, Jeremy; Lepage, Hugo; Lefèvre, Irène; Ayrault, Sophie; Ottlé, Catherine; Bonté, Philippe

    2013-10-29

    Measurement of radioactive dose rates in fine sediment that has recently deposited on channel bed-sand provides a solution to address the lack of continuous river monitoring in Fukushima Prefecture after Fukushima Dai-ichi nuclear power plant (FDNPP) accident. We show that coastal rivers of Eastern Fukushima Prefecture were rapidly supplied with sediment contaminated by radionuclides originating from inland mountain ranges, and that this contaminated material was partly exported by typhoons to the coastal plains as soon as by November 2011. This export was amplified during snowmelt and typhoons in 2012. In 2013, contamination levels measured in sediment found in the upper parts of the catchments were almost systematically lower than the ones measured in nearby soils, whereas their contamination was higher in the coastal plains. We thereby suggest that storage of contaminated sediment in reservoirs and in coastal sections of the river channels now represents the most crucial issue.

  8. Post-depositional formation of vivianite-type minerals alters sediment phosphorus records

    Directory of Open Access Journals (Sweden)

    N. Dijkstra

    2018-02-01

    Full Text Available Phosphorus (P concentrations in sediments are frequently used to reconstruct past environmental conditions in freshwater and marine systems, with high values thought to be indicative of a high biological productivity. Recent studies suggest that the post-depositional formation of vivianite, an iron(II-phosphate mineral, might significantly alter trends in P with sediment depth. To assess its importance, we investigate a sediment record from the Bornholm Basin that was retrieved during the Integrated Ocean Drilling Program (IODP Baltic Sea Paleoenvironment Expedition 347 in 2013, consisting of lake sediments overlain by brackish–marine deposits. Combining bulk sediment geochemistry with microanalysis using scanning electron microscope energy dispersive spectroscopy (SEM-EDS and synchrotron-based X-ray absorption spectroscopy (XAS, we demonstrate that vivianite-type minerals rich in manganese and magnesium are present in the lake deposits just below the transition to the brackish–marine sediments (at 11.5 to 12 m sediment depth. In this depth interval, phosphate that diffuses down from the organic-rich, brackish–marine sediments meets porewaters rich in dissolved iron in the lake sediments, resulting in the precipitation of iron(II phosphate. Results from a reactive transport model suggest that the peak in iron(II phosphate originally occurred at the lake–marine transition (9 to 10 m and moved downwards due to changes in the depth of a sulfidization front. However, its current position relative to the lake–marine transition is stable as the vivianite-type minerals and active sulfidization fronts have been spatially separated over time. Experiments in which vivianite was subjected to sulfidic conditions demonstrate that incorporation of manganese or magnesium in vivianite does not affect its susceptibility to sulfide-induced dissolution. Our work highlights that post-depositional formation of iron(II phosphates such as vivianite has

  9. Post-depositional formation of vivianite-type minerals alters sediment phosphorus records

    Science.gov (United States)

    Dijkstra, Nikki; Hagens, Mathilde; Egger, Matthias; Slomp, Caroline P.

    2018-02-01

    Phosphorus (P) concentrations in sediments are frequently used to reconstruct past environmental conditions in freshwater and marine systems, with high values thought to be indicative of a high biological productivity. Recent studies suggest that the post-depositional formation of vivianite, an iron(II)-phosphate mineral, might significantly alter trends in P with sediment depth. To assess its importance, we investigate a sediment record from the Bornholm Basin that was retrieved during the Integrated Ocean Drilling Program (IODP) Baltic Sea Paleoenvironment Expedition 347 in 2013, consisting of lake sediments overlain by brackish-marine deposits. Combining bulk sediment geochemistry with microanalysis using scanning electron microscope energy dispersive spectroscopy (SEM-EDS) and synchrotron-based X-ray absorption spectroscopy (XAS), we demonstrate that vivianite-type minerals rich in manganese and magnesium are present in the lake deposits just below the transition to the brackish-marine sediments (at 11.5 to 12 m sediment depth). In this depth interval, phosphate that diffuses down from the organic-rich, brackish-marine sediments meets porewaters rich in dissolved iron in the lake sediments, resulting in the precipitation of iron(II) phosphate. Results from a reactive transport model suggest that the peak in iron(II) phosphate originally occurred at the lake-marine transition (9 to 10 m) and moved downwards due to changes in the depth of a sulfidization front. However, its current position relative to the lake-marine transition is stable as the vivianite-type minerals and active sulfidization fronts have been spatially separated over time. Experiments in which vivianite was subjected to sulfidic conditions demonstrate that incorporation of manganese or magnesium in vivianite does not affect its susceptibility to sulfide-induced dissolution. Our work highlights that post-depositional formation of iron(II) phosphates such as vivianite has the potential to strongly

  10. Risk assessment of metals in road-deposited sediment along an urban–rural gradient

    International Nuclear Information System (INIS)

    Zhao, Hongtao; Li, Xuyong

    2013-01-01

    We applied the traditional risk assessment methods originally designed for soils and river sediments to evaluation of risk associated with metals in road-deposited sediment (RDS) along an urban–rural gradient that included central urban (UCA), urban village (UVA), central suburban county (CSA), rural town (RTA), and rural village (RVA) areas in the Beijing metropolitan region. A new indicator RI RDS was developed which integrated the RDS characteristics of mobility, grain size and amount with the potential ecological risk index. The risk associated with metals in RDS in urban areas was generally higher than that in rural areas based on the assessment using traditional methods, but the risk was higher in urban and rural village areas than the areas with higher administration units based on the indicator RI RDS . These findings implied that RDS characteristics variation with the urban–rural gradient must be considered in metal risk assessment and RDS washoff pollution control. Highlights: ► Spatial pattern of metal risk level associated with road-deposited sediment (RDS) along urban–rural gradients varied. ► Risk level of metals changed significantly when grain size was considered. ► A new index integrating RDS characteristics and potential ecological risk was developed. ► Results from the new index were improved relative to those of traditional assessment methods. -- A new index integrating road-deposited sediment characteristics and potential ecological risk was developed to assess metal risk along the urban–rural gradient

  11. Sediment deposition and sources into a Mississippi River floodplain lake; Catahoula Lake, Louisiana

    Science.gov (United States)

    Latuso, Karen D.; Keim, Richard F.; King, Sammy L.; Weindorf, David C.; DeLaune, Ronald D.

    2017-01-01

    Floodplain lakes are important wetlands on many lowland floodplains of the world but depressional floodplain lakes are rare in the Mississippi River Alluvial Valley. One of the largest is Catahoula Lake, which has existed with seasonally fluctuating water levels for several thousand years but is now in an increasingly hydrologically altered floodplain. Woody vegetation has been encroaching into the lake bed and the rate of this expansion has increased since major human hydrologic modifications, such as channelization, levee construction, and dredging for improvement of navigation, but it remains unknown what role those modifications may have played in altering lake sedimentation processes. Profiles of thirteen 137Cs sediment cores indicate sedimentation has been about 0.26 cm y− 1 over the past 60 years and has been near this rate since land use changes began about 200 years ago (210Pb, and 14C in Tedford, 2009). Carbon sequestration was low (10.4 g m− 2 y− 1), likely because annual drying promotes mineralization and export. Elemental composition (high Zr and Ti and low Ca and K) and low pH of recent (sediments suggest Gulf Coastal Plain origin, but below the recent sediment deposits, 51% of sediment profiles showed influence of Mississippi River alluvium, rich in base cations such as K+, Ca2 +, and Mg2 +. The recent shift to dominance of Coastal Plain sediments on the lake-bed surface suggests hydrologic modification has disconnected the lake from sediment-bearing flows from the Mississippi River. Compared to its condition prior to hydrologic alterations that intensified in the 1930s, Catahoula Lake is about 15 cm shallower and surficial sediments are more acidic. Although these results are not sufficient to attribute ecological changes directly to sedimentological changes, it is likely the altered sedimentary and hydrologic environment is contributing to the increased dominance of woody vegetation.

  12. Arctic deltaic lake sediments as recorders of fluvial organic matter deposition

    Directory of Open Access Journals (Sweden)

    Jorien E Vonk

    2016-08-01

    Full Text Available Arctic deltas are dynamic and vulnerable regions that play a key role in land-ocean interactions and the global carbon cycle. Delta lakes may provide valuable historical records of the quality and quantity of fluvial fluxes, parameters that are challenging to investigate in these remote regions. Here we study lakes from across the Mackenzie Delta, Arctic Canada, that receive fluvial sediments from the Mackenzie River when spring flood water levels rise above natural levees. We compare downcore lake sediments with suspended sediments collected during the spring flood, using bulk (% organic carbon, % total nitrogen, 13C, 14C and molecular organic geochemistry (lignin, leaf waxes. High-resolution age models (137Cs, 210Pb of downcore lake sediment records (n=11 along with lamina counting on high-resolution radiographs show sediment deposition frequencies ranging between annually to every 15 years. Down-core geochemical variability in a representative delta lake sediment core is consistent with historical variability in spring flood hydrology (variability in peak discharge, ice jamming, peak water levels. Comparison with earlier published Mackenzie River depth profiles shows that (i lake sediments reflect the riverine surface suspended load, and (ii hydrodynamic sorting patterns related to spring flood characteristics are reflected in the lake sediments. Bulk and molecular geochemistry of suspended particulate matter from the spring flood peak and lake sediments are relatively similar showing a mixture of modern higher-plant derived material, older terrestrial permafrost material, and old rock-derived material. This suggests that deltaic lake sedimentary records hold great promise as recorders of past (century-scale riverine fluxes and may prove instrumental in shedding light on past behaviour of arctic rivers, as well as how they respond to a changing climate.

  13. 3D Numerical Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in Wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2009-01-01

    concrete channel with width of 0.8 m and a water depth of approximately 0.8 m and in circular flume experiments in order to reproduce near-bed specific processes such as resuspension and consolidation. With good agreement with measurements, modelling of hydrodynamics, transport of dissolved pollutants...... and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  14. Sediment problems in urban areas

    Science.gov (United States)

    Guy, Harold P.

    1970-01-01

    A recognition of and solution to sediment problems in urban areas is necessary if society is to have an acceptable living environment. Soil erosion and sediment deposition in urban areas are as much an environmental blight as badly paved and littered streets, dilapidated buildings, billboard clutter, inept land use, and air, water, and noise pollution. In addition, sediment has many direct and indirect effects on streams that may be either part of or very remote from the urban environment. Sediment, for example, is widely recognized as a pollutant of streams and other water bodies.

  15. Transport and deposition of plutonium-contaminated sediments by fluvial processes, Los Alamos Canyon, New Mexico

    International Nuclear Information System (INIS)

    Graf, W.L.

    1996-01-01

    Between 1945 and 1952 the development of nuclear weapons at Los Alamos National Laboratory, New Mexico, resulted in the disposal of plutonium into the alluvium of nearby Acid and (to a lesser degree) DP Canyons. The purpose of this paper is to explore the connection between the disposal sites and the main river, a 20 km link formed by the fluvial system of Acid, Pueblo, DP, and Los Alamos Canyons. Empirical data from 15 yr of annual sediment sampling throughout the canyon system has produced 458 observations of plutonium concentration in fluvial sediments. These data show that, overall, mean plutonium concentrations in fluvial sediment decline from 10,000 fCi/g near the disposal area to 100 fCi/g at the confluence of the canyon system and the Rio Grande. Simulations using a computer model for water, sediment, and plutonium routing in the canyon system show that discharges as large as the 25 yr event would fail to develop enough transport capacity to completely remove the contaminated sediments from Pueblo Canyon. Lesser flows would move some materials to the Rio Grande by remobilization of stored sediments. The simulations also show that the deposits and their contaminants have a predictable geography because they occur where stream power is low, hydraulic resistance is high, and the geologic and/or geomorphic conditions provide enough space for storage. 38 refs., 13 figs., 1 tab

  16. Geometrical Characterization of Sediment Deposits at the Confluence of Mountain Streams

    Directory of Open Access Journals (Sweden)

    Laura Maria Stancanelli

    2018-03-01

    Full Text Available Debris flow injections from tributaries into a main mountain stream generate deposits of sediments which, in turn, result in obstruction and eventual damming of the river section. This contribution presents the results of a series of flume experiments on the dynamics of these deposits, with reference to three different types of blockage: no blockage, partial blockage, and full blockage. Results show that the shape of the deposit is mainly controlled by the ratio between the debris flow discharge and the main river discharge. The experimental dataset is used to develop a deposit resilience stability index based on the shape of the deposit contour retrieved from photos taken from above. The proposed index is based on the invariant elliptic Fourier coefficients and the dimensionless transverse obstruction parameter. The elliptic Fourier coefficients give information on the symmetry of the deposit contour. High symmetry indicates more stable and resilient deposits. The proposed index is calibrated on the basis of the flume experiments and tested with field data. The results are quite promising and suggest that the index can be appropriate for a fast hazard assessment of multiple debris flow deposits at a regional scale.

  17. Deposition of plutonium isotopes and Cs-137 in sediments of the Ob delta from the beginning of the nuclear age

    International Nuclear Information System (INIS)

    Panteleyev, G.P.; Livingston, H.D.; Sayles, F.L.; Medkova, O.N.

    1995-01-01

    As an approach to an assessment of the transport of artificial radionuclides through the Ob river system towards the arctic Ocean, results are presented from the analyses of a series of sediment cores collected in the Ob delta and estuary in 1994. These cores, collected in areas of sediment accumulation, contain the depositional history at the Ob mouth of substances associated with sediment particles from the whole river system watershed. Several approaches to dating these sediments permitted the development of a chronology for the deposition of plutonium isotopes and Cs-137, following their first introduction to the environment a half century ago. Some preliminary results for I-129 are also presented. 6 figs

  18. Comparative analyses of the bacterial community of hydrothermal deposits and seafloor sediments across Okinawa Trough

    Science.gov (United States)

    Wang, Long; Yu, Min; Liu, Yan; Liu, Jiwen; Wu, Yonghua; Li, Li; Liu, Jihua; Wang, Min; Zhang, Xiao-Hua

    2018-04-01

    As an ideal place to study back-arc basins and hydrothermal eco-system, Okinawa Trough has attracted the interests of scientists for decades. However, there are still no in-depth studies targeting the bacterial community of the seafloor sediments and hydrothermal deposits in Okinawa Trough. In the present study, we reported the bacterial community of the surface deposits of a newly found hydrothermal field in the southern Okinawa Trough, and the horizontal and vertical variation of bacterial communities in the sediments of the northern Okinawa Trough. The hydrothermal deposits had a relatively high 16S rRNA gene abundance but low bacterial richness and diversity. Epsilonproteobacteria and Bacteroidetes were predominant in hydrothermal deposits whereas Deltaproteobacteria, Gammaproteobacteria and Chloroflexi were abundant across all samples. The bacterial distribution in the seafloor of Okinawa Trough was significantly correlated to the content of total nitrogen, and had consistent relationship with total carbon. Gradual changes of sulfur-oxidizing bacteria were found with the distance away from hydrothermal fields, while the hydrothermal activity did not influence the distribution of the major clades of sulfate-reducing bacteria. Higher abundance of the sulfur cycle related genes (aprA and dsrB), and lower abundance of the bacterial ammonia-oxidizing related gene (amoA) were quantified in hydrothermal deposits. In addition, the present study also compared the inter-field variation of Epsilonproteobacteria among multi-types of hydrothermal vents, revealing that the proportion and diversity of this clade were quite various.

  19. Sediment transport and deposition on a river-dominated tidal flat: An idealized model study

    Science.gov (United States)

    Sherwood, Christopher R.; Chen, Shih-Nan; Geyer, W. Rockwell; Ralston, David K.

    2010-01-01

    A 3-D hydrodynamic model is used to investigate how different size classes of river-derived sediment are transported, exported and trapped on an idealized, river-dominated tidal flat. The model is composed of a river channel flanked by sloping tidal flats, a configuration motivated by the intertidal region of the Skagit River mouth in Washington State, United States. It is forced by mixed tides and a pulse of freshwater and sediment with various settling velocities. In this system, the river not only influences stratification but also contributes a significant cross-shore transport. As a result, the bottom stress is strongly ebb-dominated in the channel because of the seaward advance of strong river flow as the tidal flats drain during ebbs. Sediment deposition patterns and mass budgets are sensitive to settling velocity. The lateral sediment spreading scales with an advective distance (settling time multiplied by lateral flow speed), thereby confining the fast settling sediment classes in the channel. Residual sediment transport is landward on the flats, because of settling lag, but is strongly seaward in the channel. The seaward transport mainly occurs during big ebbs and is controlled by a length scale ratio Ld/XWL, where Ld is a cross-shore advective distance (settling time multiplied by river outlet velocity), and XWL is the immersed cross-shore length of the intertidal zone. Sediment trapping requires Ld/XWL stratification and reducing tidal range both favor sediment trapping, whereas varying channel geometries and asymmetry of tides has relatively small impacts. Implications of the modeling results on the south Skagit intertidal region are discussed.

  20. Hydraulic experiment on formation mechanism of tsunami deposit and verification of sediment transport model for tsunamis

    Science.gov (United States)

    Yamamoto, A.; Takahashi, T.; Harada, K.; Sakuraba, M.; Nojima, K.

    2017-12-01

    An underestimation of the 2011 Tohoku tsunami caused serious damage in coastal area. Reconsideration for tsunami estimation needs knowledge of paleo tsunamis. The historical records of giant tsunamis are limited, because they had occurred infrequently. Tsunami deposits may include many of tsunami records and are expected to analyze paleo tsunamis. However, present research on tsunami deposits are not able to estimate the tsunami source and its magnitude. Furthermore, numerical models of tsunami and its sediment transport are also important. Takahashi et al. (1999) proposed a model of movable bed condition due to tsunamis, although it has some issues. Improvement of the model needs basic data on sediment transport and deposition. This study investigated the formation mechanism of tsunami deposit by hydraulic experiment using a two-dimensional water channel with slope. In a fixed bed condition experiment, velocity, water level and suspended load concentration were measured at many points. In a movable bed condition, effects of sand grains and bore wave on the deposit were examined. Yamamoto et al. (2016) showed deposition range varied with sand grain sizes. In addition, it is revealed that the range fluctuated by number of waves and wave period. The measurements of velocity and water level showed that flow was clearly different near shoreline and in run-up area. Large velocity by return flow was affected the amount of sand deposit near shoreline. When a cutoff wall was installed on the slope, the amount of sand deposit repeatedly increased and decreased. Especially, sand deposit increased where velocity decreased. Takahashi et al. (1999) adapted the proposed model into Kesennuma bay when the 1960 Chilean tsunami arrived, although the amount of sand transportation was underestimated. The cause of the underestimation is inferred that the velocity of this model was underestimated. A relationship between velocity and sediment transport has to be studied in detail, but

  1. Urban streets

    NARCIS (Netherlands)

    Schönfeld, von Kim Carlotta; Bertolini, Luca

    2017-01-01

    Today's urban streets are usually planned for purposes of mobility: pedestrians, as well as a variety of vehicles such as cars, trucks, and sometimes bicycles, are usually factored into an urban street plan. However, urban streets are also increasingly recognized as public spaces, accommodating

  2. Radionuclides deposition and fine sediment transport in a forested watershed, central Japan

    Science.gov (United States)

    Nam, S.; Gomi, T.; Kato, H.; Tesfaye, T.; Onda, Y.

    2011-12-01

    We investigated radionuclides deposition and fine sediment transport in a 13 ha headwater watershed, Tochigi prefecture, located in 98.94 km north of Tokyo. The study site was within Karasawa experimental forest, Tokyo University of Agriculture and Technology. We conducted fingerprinting approach, based on the activities of fallout radionuclides, including caesium-134 (Cs-134) caesium-137 (Cs-137) and excess lead-210 (Pb-210ex). For indentifying specific sources of fine sediment, we sampled tree, soil on forested floor, soil on logging road surface, stream bed and stream banks. We investigated the radionuclides (i.e., as Cs-134, Cs-137 and Pb-210ex) deposition on tree after accident of nuclear power plants on March 11, 2011. We sampled fruits, leaves, branches, stems, barks on Japanese cedar (Sugi) and Japanese cypress (Hinoki). To analyze the samples, gammaray spectrometry was performed at a laboratory at the University of Tsukuba (Tsukuba City, Japan) using n-type coaxial low-energy HPGe gamma detectors (EGC-200-R and EGC25-195-R of EURYSIS Co., Lingolsheim, France) coupled with a multichannel analyzer. We also collected soil samples under the forest canopy in various soil depths from 2, 5, 10, 20, 30 cm along transect of hillslopes. Samples at forest road were collected road segments crossing on the middle section of monitoring watersheds. Fine sediment transport in the streams were collected at the outlet of 13 ha watersheds using integrated suspended sediment samplers. This study indicates the some portion of radio nuclide potentially remained on the tree surface. Part of the deposited radionuclides attached to soil particles and transported to the streams. Most of the fine sediment can be transported on road surface and/or near stream side (riparian zones).

  3. Physicochemical and biological characterisation of different dredged sediment deposit sites in France

    International Nuclear Information System (INIS)

    Capilla, Xavier; Schwartz, Christophe; Bedell, Jean-Philippe; Sterckeman, Thibault; Perrodin, Yves; Morel, Jean-Louis

    2006-01-01

    The aim of this work is to determine sediment properties, metal contents and transfers of Cd and Zn from dredged sediments to plants. To this end 10 deposit sites with different contexts were visited in France. The main agronomic characteristics and metal contents for surface soil layers were measured, the plant species present at the sites, such as Brassicaceae and Fabaceae, were listed, and the distribution of their root systems described. Soil characteristics such as available P (Olsen) varied between sites, with values ranging from 0.01 to 0.49 g kg -1 . Total contents and enrichment factors were studied, highlighting metal contamination in most of the sites. Despite carrying out principal component analyses, it was not possible to group deposits by age or geographical localisation. However, deposits could be distinguished as a function of proximity of industrial facilities, sediment grain size and carbonate content. Associations between metals were also highlighted: (1) Cd, Pb and Zn, and (2) Al, Cr, Cu and Fe. Consequently, we propose classifying them as technogenic anthrosols. - The term technogenic arthrosols is suggested

  4. Physicochemical and biological characterisation of different dredged sediment deposit sites in France

    Energy Technology Data Exchange (ETDEWEB)

    Capilla, Xavier [Laboratoire des Sciences de l' Environnement a l' ENTPE, Rue Maurice Audin, 69 518 Vaulx-en-Velin Cedex (France); Schwartz, Christophe [Laboratoire Sols et Environnement, INPL (ENSAIA)/INRA UMR 1120, 2 avenue de la foret de Haye, BP 172, 54 505 Vandoeuvre les Nancy (France); Bedell, Jean-Philippe [Laboratoire des Sciences de l' Environnement a l' ENTPE, Rue Maurice Audin, 69 518 Vaulx-en-Velin Cedex (France)]. E-mail: bedell@entpe.fr; Sterckeman, Thibault [Laboratoire Sols et Environnement, INPL (ENSAIA)/INRA UMR 1120, 2 avenue de la foret de Haye, BP 172, 54 505 Vandoeuvre les Nancy (France); Perrodin, Yves [Laboratoire des Sciences de l' Environnement a l' ENTPE, Rue Maurice Audin, 69 518 Vaulx-en-Velin Cedex (France); Morel, Jean-Louis [Laboratoire Sols et Environnement, INPL (ENSAIA)/INRA UMR 1120, 2 avenue de la foret de Haye, BP 172, 54 505 Vandoeuvre les Nancy (France)

    2006-09-15

    The aim of this work is to determine sediment properties, metal contents and transfers of Cd and Zn from dredged sediments to plants. To this end 10 deposit sites with different contexts were visited in France. The main agronomic characteristics and metal contents for surface soil layers were measured, the plant species present at the sites, such as Brassicaceae and Fabaceae, were listed, and the distribution of their root systems described. Soil characteristics such as available P (Olsen) varied between sites, with values ranging from 0.01 to 0.49 g kg{sup -1}. Total contents and enrichment factors were studied, highlighting metal contamination in most of the sites. Despite carrying out principal component analyses, it was not possible to group deposits by age or geographical localisation. However, deposits could be distinguished as a function of proximity of industrial facilities, sediment grain size and carbonate content. Associations between metals were also highlighted: (1) Cd, Pb and Zn, and (2) Al, Cr, Cu and Fe. Consequently, we propose classifying them as technogenic anthrosols. - The term technogenic arthrosols is suggested.

  5. Effects of storm waves on rapid deposition of sediment in the Yangtze Estuary channel

    Directory of Open Access Journals (Sweden)

    Xu Fumin

    2008-03-01

    Full Text Available Recent research on short-term topographic change in the Yangtze Estuary channel under storm surge conditions is briefly summarized. The mild-slope, Boussinesq and action balance equations are compared and analyzed. The action balance equation, SWAN, was used as a wave numerical model to forecast strong storm waves in the Yangtze Estuary. The spherical coordinate system and source terms used in the equation are described in this paper. The significant wave height and the wave orbital motion velocity near the bottom of the channel during 20 m/s winds in the EES direction were simulated, and the model was calibrated with observation data of winds and waves generated by Tropical Cyclone 9912. The distribution of critical velocity for incipient motion along the bottom was computed according to the threshold velocity formula for bottom sediment. The mechanism of rapid deposition is analyzed based on the difference between the root-mean-square value of the near-bottom wave orbital motion velocity and the bottom critical tractive velocity. The results show that a large amount of bottom sediments from Hengsha Shoal and Jiuduan Shoal are lifted into the water body when 20 m/s wind is blowing in the EES direction. Some of the sediments may enter the channel with the cross-channel current, causing serious rapid deposition. Finally, the tendency of the storm to induce rapid deposition in the Yangtze Estuary channel zone is analyzed.

  6. Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults

    Science.gov (United States)

    Miller, David; Haddon, Elizabeth; Langenheim, Victoria; Cyr, Andrew J.; Wan, Elmira; Walkup, Laura; Starratt, Scott W.

    2018-01-01

    Hinkley Valley in the Mojave Desert, near Barstow about 140 km northeast of Los Angeles and midway between Victorville Valley and the Lake Manix basin, contains a thick sedimentary sequence delivered by the Mojave River. Our study of sediment cores drilled in the valley indicates that Hinkley Valley was probably a closed playa basin with stream inflow from four directions prior to Mojave River inflow. The Mojave River deposited thick and laterally extensive clastic wedges originating from the southern valley that rapidly filled much of Hinkley Valley. Sedimentary facies representing braided stream, wetland, delta, and lacustrine depositional environments all are found in the basin fill; in some places, the sequence is greater than 74 m (245 ft) thick. The sediment is dated in part by the presence of the ~631 ka Lava Creek B ash bed low in the section, and thus represents sediment deposition after Victorville basin was overtopped by sediment and before the Manix basin began to be filled. Evidently, upstream Victorville basin filled with sediment by about 650 ka, causing the ancestral Mojave River to spill to the Harper and Hinkley basins, and later to Manix basin.Initial river sediment overran wetland deposits in many places in southern Hinkley Valley, indicating a rapidly encroaching river system. These sediments were succeeded by a widespread lake (“blue” clay) that includes the Lava Creek B ash bed. Above the lake sediment lies a thick section of interlayered stream sediment, delta and nearshore lake sediment, mudflat and/or playa sediment, and minor lake sediment. This stratigraphic architecture is found throughout the valley, and positions of lake sediment layers indicate a successive northward progression in the closed basin. A thin overlapping sequence at the north end of the valley contains evidence for a younger late Pleistocene lake episode. This late lake episode, and bracketing braided stream deposits of the Mojave River, indicate that the river

  7. Sediment quality in depositional areas of Shelikof Strait and outermost Cook Inlet, July 1997 - July 1998 (NODC Accession 0000702)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Minerals Management Service (MMS) program "Sediment Quality in Depositional Areas of Shelikof Strait and Outermost Cook Inlet," consisted of a two-year study...

  8. Lithology, monsoon and sea-surface current control on provenance, dispersal and deposition of sediments over the Andaman continental shelf

    Digital Repository Service at National Institute of Oceanography (India)

    Damodararao, K.; Singh, S.K.; Rai, V.K.; Ramaswamy, V.; Rao, P.S.

    , constrain their transport pathways and assess the factors influencing the erosion in the catchment and their dispersal and deposition over the Andaman Shelf region. Major elemental compositions of the shelf sediments suggest mafic lithology...

  9. A source mixing model to apportion PAHs from coal tar and asphalt binders in street pavements and urban aquatic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, M.J.; Depree, C.V. [National Institute of Water & Atmospheric Research, Hamilton (New Zealand)

    2010-12-15

    Present-day and more than 30 years old road and footpath pavements from Auckland, New Zealand were analysed for PAHs to test the hypothesis that coal tar based pavement binders contribute to unusually high PAH concentrations in adjacent stream and estuarine sediments Total PAH ({Sigma}{sub 28}PAH) concentrations in the dichloromethane-soluble fraction ('binder'), comprising 5-10% of pavement mass, were as high as 200 000 mg kg{sup -1}(10 000 mg kg{sup -1} in binder + aggregate) Older and deeper pavement layers were strongly pyrogenic, whereas pavement layers from recently sealed roads had a more petrogenic composition and more than 1000 times lower Sigma(28)PAH concentrations. Source identification analysis using three PAH isomer ratio pairs (benz(a)anthracene/(benz(a)anthracene + chrysene), benzo(a)pyrene/(benzo(a)pyrene + benzo(e)pyrene)), and indeno(1,2,3-cd)pyrene/(indeno(1,2,3-cd)pyrene + benzo(g,h,i)perylene) revealed low PAH (bitumen) pavements to have consistently lower isomer ratios than high PAH (coal tar) samples. A concentration-weighted mixing model, with coal tar and bitumen as source materials, explained more than 80% of the variance in isomer ratios and enveloped the entire PAH compositional and concentration range encountered PAH composition and concentrations in adjacent stream sediments ({gt} 15 mg kg{sup -1} dry weight) were consistent with diluted coal tar material as a principal PAH source. Due to the very high PAH concentrations of coal tar, a coal tar content of as little as 0.01% of total sediment mass can account for more than 90% of PAH concentrations in adjacent stream sediments.

  10. Characteristics of uranium mineralization and depositional system of host sediments, Bayantala basin, Inner Mongolia autonomous region

    International Nuclear Information System (INIS)

    Zhu Minqiang; Wu Rengui; Yu Dagan; Chen Anping; Shen Kefeng

    2003-01-01

    Based upon the research of basin fills at the Bayantala basin, the genetic facies of host sediments have been ascertained and the target beds and their range are delineated. The sand bodies of the Upper Member of Tengge'er Formation deposited in fan delta front is favorable to the formation of uranium mineralization of phreatic-interlayer oxidation. The Saihantala Fm deposited in fluvial system can be divided into Lower Member and Upper Member based on depositional microfacies and paleoclimate. The Lower Member of braided system is the most important target bed enriched in organic matter where basal-channel-type uranium mineralization occurs. Features of alteration and mineralization suggest that the early-stage and the late-stage uranium mineralization are related to phreatic oxidation and interlayer oxidation (roll-type) respectively. Meanwhile, the secondary reduction has superimposed over the earlier mineralization in the area caused by hydrocarbons raising along faults

  11. Conditions of sedimentation of deposits of the lower section of the productive strata and their natural radioactivity

    International Nuclear Information System (INIS)

    Alieva, E.G.; Aliev, Ch.S.; Huseynov, D.A.

    2008-01-01

    In this article for the time for sedimentary deposits of the southern Caspian basin is an attempt use of the data of natural radioactivity of sediments in order to reconstruct their conditions sedimentation. The results obtained show a good comparability of the nature of the distribution of radioactive elements with the conditions of sedimentation. Clear contents of dependency is detected radioactive elements from the source of sedimentary material that can be successfully used in conducting the paleo facial and paleogeographic building.

  12. The Effect of Suspended Sediment Transport and Deposition on Streambed Clogging Under Losing and Gaining Flow Conditions

    Science.gov (United States)

    Fox, A.; Packman, A. I.; Preziosi-Ribero, A.; Li, A.; Arnon, S.

    2017-12-01

    Sediment transport and deposition in streams can affect streambed hydraulic characteristics due to clogging, reduce water fluxes through the hyporheic zone, and thus expected to affect biogeochemical processes. Processes affecting deposition of suspended particles were systematically studied under various overlying velocities but without taking into account the interactions with groundwater. This is despite the fact that the interaction with groundwater were shown to play an important role in deposition patterns of fine sediments in field studies. The objective of this study was to evaluate the effect of losing and gaining fluxes on suspended sediment depositional patterns and on hyporheic exchange fluxes. Experiments were conducted in a laboratory flume system (640 cm long and 30 cm wide) that has a capacity to enforce losing or gaining flow conditions. The flume was packed with homogenous sand, while suspended sediment deposition was evaluated by adding kaolinite particles to the water and following the deposition rate by particle disappearance from the bulk water. Consecutive additions of kaolinite were done, while hyporheic exchange fluxes were evaluated by conducting NaCl tracer experiments between each kaolinite additions. Furthermore, dye injections were used to visualize the flow patterns in the streambed using time-lapse photography through the transparent sidewalls of the flume. Hyporheic exchange and particle tracking simulations were done to assess the results of particle deposition and feedbacks between hyporheic flow, particle transport, and streambed clogging. Experimental results showed that the deposition of clay decreases with increasing amount of clay concentration in the sediment. Hyporheic exchange flux decreases linearly with increasing amount of clay added to the system and the region of active hyporheic exchange was confined to the upper part of the sediment. Understanding the particle deposition mechanisms under losing and gaining flow

  13. Sedimentological characteristics and depositional processes of sediment gravity flows in rift basins: The Palaeogene Dongying and Shahejie formations, Bohai Bay Basin, China

    Science.gov (United States)

    Liu, Lei; Chen, Hongde; Zhong, Yijiang; Wang, Jun; Xu, Changgui; Chen, Anqing; Du, Xiaofeng

    2017-10-01

    Sediment gravity flow deposits are common, particularly in sandy formations, but their origin has been a matter of debate and there is no consensus about the classification of such deposits. However, sediment gravity flow sandstones are economically important and have the potential to meet a growing demand in oil and gas exploration, so there is a drive to better understand them. This study focuses on sediment gravity flow deposits identified from well cores in Palaeogene deposits from the Liaodong Bay Depression in Bohai Bay Basin, China. We classify the sediment gravity flow deposits into eight lithofacies using lithological characteristics, grain size, and sedimentary structures, and interpret the associated depositional processes. Based on the scale, spatial distribution, and contact relationships of sediment gravity flow deposits, we defined six types of lithofacies associations (LAs) that reflect transformation processes and depositional morphology: LA1 (unconfined proximal breccia deposits), LA2 (confined channel deposits), LA3 (braided-channel lobe deposits), LA4 (unconfined lobe deposits), LA5 (distal sheet deposits), and LA6 (non-channelized sheet deposits). Finally, we established three depositional models that reflect the sedimentological characteristics and depositional processes of sediment gravity flow deposits: (1) slope-apron gravel-rich depositional model, which involves cohesive debris flows deposited as LA1 and dilute turbidity currents deposited as LA5; (2) non-channelized surge-like turbidity current depositional model, which mainly comprises sandy slumping, suspended load dominated turbidity currents, and dilute turbidity currents deposited as LA5 and LA6; and (3) channelized subaqueous-fan depositional model, which consists of non-cohesive bedload dominated turbidity currents, suspended load dominated turbidity currents, and dilute turbidity currents deposited as LA2-LA5, originating from sustained extrabasinal turbidity currents

  14. Investigations of contaminated fluvial sediment deposits: merging of statistical and geomorphic approaches.

    Science.gov (United States)

    Ryti, Randall T; Reneau, Steven L; Katzman, Danny

    2005-05-01

    Concentrations of contaminants in sediment deposits can have large spatial variability resulting from geomorphic processes acting over long time periods. Thus, systematic (e.g., regularly spaced sample locations) or random sampling approaches might be inefficient and/or lead to highly biased results. We demonstrate the bias associated with systematic sampling and compare these results to those achieved by methods that merge a geomorphic approach to evaluating the physical system and stratified random sampling concepts. By combining these approaches, we achieve a more efficient and less biased characterization of sediment contamination in fluvial systems. These methods are applied using a phased sampling approach to characterize radiological contamination in sediment deposits in two semiarid canyons that have received historical releases from the Los Alamos National Laboratory. Uncertainty in contaminant inventory was used as a metric to evaluate the adequacy of sampling during these phased investigations. Simple, one-dimensional Monte Carlo simulations were used to estimate uncertainty in contaminant inventory. We also show how one can use stratified random sampling theory to help estimate uncertainty in mean contaminant concentrations.

  15. Preparation Of Deposited Sediment Sample By Casting Method For Environmental Study

    International Nuclear Information System (INIS)

    Hutabarat, Tommy; Ristin PI, Evarista

    2000-01-01

    The preparation of deposited sediment sample by c asting m ethod for environmental study has been carried out. This method comprises separation of size fraction and casting process. The deposited sediment samples were wet sieved to separate the size fraction of >500 mum, (250-500) mum, (125-250) mum and (63-125) mum and settling procedures were followed for the separation of (40-63) mum, (20-40) mum, (10-20) mum and o C, ashed at 450 o C, respectively. In the casting process of sample, it was used polyester rapid cure resin and methyl ethyl ketone peroxide (MEKP) hardener. The moulded sediment sample was poured onto caster, allow for 60 hours long. The aim of this method is to get the casted sample which can be used effectively, efficiently and to be avoided from contamination of each other samples. Before casting, samples were grinded up to be fine. The result shows that casting product is ready to be used for natural radionuclide analysis

  16. Patterns of floodplain sediment deposition along the regulated lower Roanoke River, North Carolina: annual, decadal, centennial scales

    Science.gov (United States)

    Hupp, Cliff R.; Schenk, Edward R.; Kroes, Daniel; Willard, Debra A.; Townsend, Phil A.; Peet, Robert K.

    2015-01-01

    The lower Roanoke River on the Coastal Plain of North Carolina is not embayed and maintains a floodplain that is among the largest on the mid-Atlantic Coast. This floodplain has been impacted by substantial aggradation in response to upstream colonial and post-colonial agriculture between the mid-eighteenth and mid-nineteenth centuries. Additionally, since the mid-twentieth century stream flow has been regulated by a series of high dams. We used artificial markers (clay pads), tree-ring (dendrogeomorphic) techniques, and pollen analyses to document sedimentation rates/amounts over short-, intermediate-, and long-term temporal scales, respectively. These analyses occurred along 58 transects at 378 stations throughout the lower river floodplain from near the Fall Line to the Albemarle Sound. Present sediment deposition rates ranged from 0.5 to 3.4 mm/y and 0.3 to 5.9 mm/y from clay pad and dendrogeomorphic analyses, respectively. Deposition rates systematically increased from upstream (high banks and floodplain) to downstream (low banks) reaches, except the lowest reaches. Conversely, legacy sediment deposition (A.D. 1725 to 1850) ranged from 5 to about 40 mm/y, downstream to upstream, respectively, and is apparently responsible for high banks upstream and large/wide levees along some of the middle stream reaches. Dam operations have selectively reduced levee deposition while facilitating continued backswamp deposition. A GIS-based model predicts 453,000 Mg of sediment is trapped annually on the floodplain and that little watershed-derived sediment reaches the Albemarle Sound. Nearly all sediment in transport and deposited is derived from the channel bed and banks. Legacy deposits (sources) and regulated discharges affect most aspects of present fluvial sedimentation dynamics. The lower river reflects complex relaxation conditions following both major human alterations, yet continues to provide the ecosystem service of sediment trapping.

  17. Sediment deposition rate in the Falefa River basin, Upolu Island, Samoa

    International Nuclear Information System (INIS)

    Terry, James P.; Kostaschuk, Ray A.; Garimella, Sitaram

    2006-01-01

    The 137 Cs method was employed to investigate the recent historical rate of sediment deposition on a lowland alluvial floodplain in the Falefa River basin, Upolu Island, Samoa. Caesium stratigraphy in the floodplain sediment profile was clearly defined, with a broad peak at 145-175 cm depth. The measured rate of vertical accretion over the last 40 years is 4.0 ± 0.4 cm per year. This rate exceeds observations in humid environments elsewhere, but is similar to that recorded on other tropical Pacific Islands. Available flow data for the Vaisigano River in Samoa give a 'near-catastrophic' index value of 0.6 for flood variability. This is associated with the occurrence of tropical cyclones and storms in the Samoa area. Large floods therefore probably contribute to the high rate of floodplain sedimentation on Upolu Island. A small but growing body of evidence suggests that fluvial sedimentation rates on tropical Pacific islands are some of the highest in the world

  18. Millennial-scale record of overwash deposits preserved within lagoon sediments from the Arabian Peninsula

    Science.gov (United States)

    Griffis, A. M.; Jessica, P.; Reinhardt, E. G.; Kosciuch, T. J.; Kovacs, S. E.; Hoffmann, G.

    2017-12-01

    Coastlines along the Arabian Sea are susceptible to tsunami-related inundation due to their proximity to the Makran Subduction Zone (MSZ). This subduction zone has seen decades of low intensity events, but has historically produced large tsunamigenic-earthquakes that have impacted the 100 million people living along the Arabian Sea. One major problem in assessing the seismic risk of the MSZ is that the historical record of events are spatially and temporally limited and rely heavily on eye witness accounts. This hinders our ability to forecast the potential magnitude and recurrence intervals of earthquakes and tsunamis that can be expected in the future. Sediments deposited by paleotsunamis are useful as they expand the decadal record of events to include millennial timescales that more accurately capture the full range of magnitudes and recurrence intervals. On November 28, 1945 a 8.1 Mw earthquake originating from the MSZ generated a tsunami inundating coastlines along the Arabian Sea with wave heights up to 13m. At Sur, a small village on the northeastern coastline of Oman, the tsunami deposited a laterally continuous shell-rich layer within a 12 km2 lagoon. This layer contained distinctive taphonomic assemblages of foraminifera and bivalves. Below the 1945 shelly deposit at Sur Lagoon, seven anomalous sand layers were found preserved within fine-grained lagoonal sediment. These layers of medium-coarse sands range in thickness from 5 to 35 cm and are separated by sandy-mud sediment. Grain size analysis shows that these anomalously coarse layers are followed by an abrupt return to lagoonal mud. The sand layers have features consistent with the 1945 tsunami deposit such as fining upward trends, sharp basal contact, and marine foraminifera (e.g., Amphistegina sp., planktics). In contrast, the surrounding lagoon deposits are generally massive, finer in grain size, and contain foraminiferal species typically found in shallow quiescent coastal environments (e

  19. Street children

    Directory of Open Access Journals (Sweden)

    Rončević Nevenka

    2013-01-01

    Full Text Available According to UNICEF, street child is any child under the age of 18 for whom the street has become home and/or source of income and which is not adequately protected or supervised by adult, responsible person. It has been estimated that there are between 100 and 150 million street children worldwide. Life and work on the street have long term and far-reaching consequences for development and health of these children. By living and working in the street, these children face the highest level of risk. Street children more often suffer from the acute illness, injuries, infection, especially gastrointestinal, acute respiratory infections and sexually transmitted diseases, inadequate nutrition, mental disorders, and drug abuse. They are more often victims of abuse, sexual exploitation, trafficking; they have higher rate of adolescent pregnancy than their peers from poor families. Street children and youth have higher rates of hospitalization and longer hospital stay due to seriousness of illness and delayed health care. Street children/youth are reluctant to seek health care, and when they try, they face many barriers. Street children are invisible to the state and their number in Serbia is unknown. Recently, some non­governmental organizations from Belgrade, Novi Sad and Nis have recognized this problem and tried to offer some help to street children, by opening drop­in centers, but this is not enough. To solve this problem, an engagement of the state and the whole community is necessary, and primary responsibility lies in health, social and educational sector. The best interests of the child must serve as a basic guideline in all activities aimed at improving health, quality of life and rights of children involved in the life and work in the street.

  20. Effects of deposition of heavy-metal-polluted harbor mud on microbial diversity and metal resistance in sandy marine sediments

    DEFF Research Database (Denmark)

    Toes, Ann-Charlotte M; Finke, Niko; Kuenen, J Gijs

    2008-01-01

    Deposition of dredged harbor sediments in relatively undisturbed ecosystems is often considered a viable option for confinement of pollutants and possible natural attenuation. This study investigated the effects of deposition of heavy-metal-polluted sludge on the microbial diversity of sandy...... the finding that some groups of clones were shared between the metal-impacted sandy sediment and the harbor control, comparative analyses showed that the two sediments were significantly different in community composition. Consequences of redeposition of metal-polluted sediment were primarily underlined...... with cultivation-dependent techniques. Toxicity tests showed that the percentage of Cd- and Cu-tolerant aerobic heterotrophs was highest among isolates from the sandy sediment with metal-polluted mud on top....

  1. Zinc and cadmium mobility in a 5-year-old dredged sediment deposit: experiments and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Lions, J. [BRGM, Orleans (France). Water Div.; Centre National de Recherche sur les Sites et Sols Pollues, Douai (France); Lee, J. van der [Ecole des Mines de Paris, Fontainebleau (France). Geosciences - Reactive Hydrodynamics Group; Guerin, V.; Bataillard, P. [BRGM, Orleans (France). Environment and Process Div.; Centre National de Recherche sur les Sites et Sols Pollues, Douai (France); Laboudigue, A. [Ecole des Mines de Douai (France). Environmental and Civil Engineering; Centre National de Recherche sur les Sites et Sols Pollues, Douai (France)

    2007-08-15

    Background. Landfill deposits of contaminated, dredged sediments are subject to chemical alteration and especially to oxidation processes. Accordingly, sulphides are gradually oxidized leading to the formation of secondary phases and associated metals could become mobile and redistributed among the sediment components, such as carbonates, clay and freshly precipitated (hydr)oxides. Once mobilised, metals could represent a hazard for the environment and especially for drinking water supply facilities. Methods. In the present study, leaching experiments have been carried out on a dredged sediment to study metal mobilisation after 5 years of field aging. First, kinetic batch tests allowed one to evaluate the impact of solid-liquid contact time and to determine the kinetic parameters. Secondly, two types of dynamic experiments have been conducted: dynamic flush reactor and column leach test to evaluate the impact of solution renewing by excluding or not excluding the transport processes, respectively. In order to evaluate the impact of calcium on the metal mobilisation, the column leaching test is conducted with pure water and Ca(NO{sub 3}){sub 2} solution, at the beginning and at the end of the injection, respectively. Geochemical and reactive transport modelling of the experiments was performed using the geochemical code CHESS and the reactive transport model HYTEC. Results and Discussion. The studied sediment is complex with numerous reactive phases such as sulphides, (hydr)oxides, organic matter, phyllosilicates. All leaching tests highlight that zinc and cadmium are mobilised in significant concentrations and lead remains insoluble. A conceptual geochemical model of the sediment has been built to allow simulations of the whole experiments, based on a single, coherent phase description and parameter set. Simulations of the batch, flush and column experiments were performed taking into account the major reaction-controlling mechanisms including, among others, p

  2. Consequences of land use and climate changes on sediment deposition in estuaries during the last centuries

    Science.gov (United States)

    Poirier, Clément; Chaumillon, Eric; Arnaud, Fabien; Goubert, Evelyne; Sauriau, Pierre-Guy; Caurant, Florence

    2010-05-01

    Estuaries are the downstream end-member of fluvial systems. They are experiencing high sedimentation rates, thus providing good opportunities for high resolution studies of Holocene environmental changes at the land/ocean interface. From a thorough literature survey, it appears that a rapid siltation and/or an increase in sedimentation rate were recorded in many estuarine environments, concomitantly to major migrations of human population throughout the world, both in time and space. It has been clearly related to an increase in sediment supply to estuaries in Minor Asia (Bronze Age, e.g. Spezzaferri et al, 2000) and in North America and Southwest Pacific (18th and 19th centuries, e.g. Goff, 1997), in response to deforestation on catchment areas. However, this relationship is less obvious in Europe (Sorrel et al., 2009), because deforestation occurred concomitantly to climate changes of the last millennium (climate instability at the end of Medieval Warm Period, Little Ice Age) that can also explain an increase in soil erosion. Indeed, these hypotheses have been proposed to explain a similar change in Marennes-Oléron Bay (Atlantic coast of France), which consists in the sudden deposition of a few meters-thick mud drape on basal mixed mud and sand bodies (Billeaud et al., 2005). The methods used to investigate this estuarine bay so far (very high resolution seismic stratigraphy, grain size analysis and radiocarbon dating) provided relevant information about recent environmental changes, but new data are now needed for further investigation. In the present study, we provide a multi-proxy analysis of the Marennes-Oléron Bay mud drape. A new 8 m-long core (M7UC01) was sampled on an intertidal flat, its location being determined on the basis of seismic stratigraphy. Core processing included visual description, physical measurements, grain size analysis every 2.5 to 5 cm, AMS radiocarbon dating, XRF core scanning, clay mineralogy and Rock Eval analysis. Fossil molluscs

  3. Combining trace elements micro-analysis in deposited dredged sediments: EPMA and μ-XRF analysis

    International Nuclear Information System (INIS)

    Poitevin, A; Lerouge, C; Wille, G; Bataillard, P; Quinn, P; Hennet, L

    2012-01-01

    Since deposited dredged sediments are rich in metallic contaminants, they present a risk for environment. This work aims to study dredged sediments chemical composition, identify metal-carrier minerals and understand their mobility. Combining chemical and spectroscopic techniques at multi-scale for an integrative approach of trace elements (zinc, lead, iron) behaviour is therefore necessary. The global mineralogy and the chemistry of the sediment were determined by X-ray diffraction and fluorescence (XRF), respectively. Zn and Pb enriched fractions were separated using a sequential chemical extraction procedure and measured by inductively coupled plasma atomic emission and mass spectroscopy. Microanalyses using scanning electron microscopy (SEM), electron microprobe microanalysis (EPMA), combined with synchrotron radiation X-ray fluorescence (μ-XRF) were carried out to characterize mineralogical phases and identify Zn and Pb carrier minerals. Iron oxyhydroxides and iron sulphides were consistently identify as Zn and Pb carriers. The assumption that carbonate fraction was the major Zn carried phase, as demonstrated by chemical extraction results, was not verified by EPMA or μ-XRF.

  4. Street outreach with no streets.

    Science.gov (United States)

    Self, Bruce; Peters, Heather

    2005-01-01

    A street nurse position in the rural and small-town interior of British Columbia has been addressing the needs of street-involved or otherwise marginalized client populations by bringing healthcare services to wherever those clients are, rather than waiting for the clients to seek care. The primary reason for a street outreach approach is that marginalized populations face a variety of barriers to accessing traditional healthcare services--barriers such as homelessness, mental health problems, criminal involvement, lack of transportation, lack of ability to pay for prescriptions, lack of specialized or knowledgeable providers and provider discrimination. In the rural street nurse program, the target population includes the usual street nurse populations of illegal drug users and sex trade workers, which are more hidden in small communities than in larger urban centres, creating the community denial that is a barrier to healthcare access. Yet another barrier is the co-locaton of services common in small communities, where public health clinics might share a building with police services, making marginalized clients reluctant to attend clinics. The rural street nurse collaborates with public health nurses and other care providers (mental health workers, social workers, etc) with collegial advice and support, making and receiving referrals, and generally assisting one another--the street nurse through his rapport with the marginalized individuals and the others with their specialized knowledge. Rural street services are delivered whereverthe clientsfeel comfortable: a school, a drop-in centre, a mall, a youth centre or simplythe street. Services provided include sexually transmitted infection testing, chlamydia treatments, pregnancy testing emergency contraception pills and assistance with filling out forms for financial support. Accordingly, the street nurse's truck is equipped as a mobile treatment centre and office, with a cellphone and a stock of testing and

  5. Recent changes in mercury deposition and primary productivity inferred from sediments of lakes from the Hudson Bay Lowlands, Ontario, Canada

    International Nuclear Information System (INIS)

    Brazeau, Michelle L.; Poulain, Alexandre J.; Paterson, Andrew M.; Keller, Wendel; Sanei, Hamed; Blais, Jules M.

    2013-01-01

    Spatial and temporal changes in mercury (Hg) concentrations and organic carbon in lake sediments were examined from the Hudson Bay Lowlands to investigate whether Hg deposition to sediments is related to indicators of autochthonous production. Total organic carbon, “S2” carbon (mainly algal-derived OC), C:N and ∂ 13 C indicators suggest an increase in autochthonous productivity in recent decades. Up-core profiles of S2 concentrations and fluxes were significantly correlated with Hg suggesting that varying algal matter scavenging of Hg from the water column may play an important role in the temporal profiles of Hg throughout the sediment cores. Absence of significant relationship between total Hg and methyl Hg (MeHg) in surficial sediments suggested that inorganic Hg supply does not limit MeHg production. MeHg and OC were highly correlated across lakes in surface and deep sediment layers, indicating that sediment organic matter content explains part of the spatial variation in MeHg concentrations between lakes. - Highlights: ► Hg concentrations in sediment cores correlate with autochthonous organic production. ► Inorganic Hg supply in sediment does not limit MeHg production. ► Sediment methylmercury concentration is highly correlated with organic C content. - Increased mercury concentrations in lake sediment cores coincide with evidence of increased autochthonous production in lakes of the Hudson Bay Lowlands, Canada.

  6. Sediment transport and deposition in the lower Missouri River during the 2011 flood

    Science.gov (United States)

    Alexander, Jason S.; Jacobson, Robert B.; Rus, David L.

    2013-01-01

    Floodwater in the Missouri River in 2011 originated in upper-basin regions and tributaries, and then travelled through a series of large flood-control reservoirs, setting records for total runoff volume entering all six Missouri River main-stem reservoirs. The flooding lasted as long as 3 months. The U.S Geological Survey (USGS) examined sediment transport and deposition in the lower Missouri River in 2011 to investigate how the geography of floodwater sources, in particular the decanting effects of the Missouri River main-stem reservoir system, coupled with the longitudinal characteristics of civil infrastructure and valley-bottom topography, affected sediment transport and deposition in this large, regulated river system. During the flood conditions in 2011, the USGS, in cooperation with the U.S. Army Corps of Engineers, monitored suspended-sediment transport at six primary streamgages along the length of the lower Missouri River. Measured suspended-sediment concentration (SSC) in the lower Missouri River varied from approximately 150 milligrams per liter (mg/L) to 2,000 mg/L from January 1 to September 30, 2011. Median SSC increased in the downstream direction from 355 mg/L at Sioux City, Iowa, to 490 mg/L at Hermann, Missouri. The highest SSCs were measured downstream from Omaha, Nebraska, in late February when snowmelt runoff from tributaries, which were draining zones of high-sediment production, was entering the lower Missouri River, and releases of water at Gavins Point Dam were small. The combination of dilute releases of water at Gavins Point Dam and low streamflows in lower Missouri River tributaries caused sustained lowering of SSC at all streamgages from early July through late August. Suspended-sediment ranged from 5 percent washload (PW; percent silt and clay) to as much as 98 percent in the lower Missouri River from January 1 to September 30, 2011. Median PW increased in the downstream direction from 24 percent at Sioux City, Iowa, to 78 percent at

  7. City Streets

    Data.gov (United States)

    Minnesota Department of Natural Resources — This data set contains roadway centerlines for city streets found on the USGS 1:24,000 mapping series. In some areas, these roadways are current through the 2000...

  8. Soft-sediment deformation structures in cores from lacustrine slurry deposits of the Late Triassic Yanchang Fm. (central China

    Directory of Open Access Journals (Sweden)

    Yang Renchao

    2016-09-01

    Full Text Available The fine-grained autochthonous sedimentation in the deep part of a Late Triassic lake was frequently interrupted by gravity-induced mass flows. Some of these mass flows were so rich in water that they must have represented slurries. This can be deduced from the soft-sediment deformation structures that abound in cores from these lacustrine deposits which constitute the Yanchang Fm., which is present in the Ordos Basin (central China.

  9. Morphology and processes associated with the accumulation of the fine-grained sediment deposit on the southern New England shelf

    Science.gov (United States)

    Twichell, David C.; McClennen, Charles E.; Butman, Bradford

    1981-01-01

    A 13,000 km2 area of the southern New England Continental Shelf which is covered by anomalously fine-grained sediment has been surveyed by means of high-resolution, seismic-reflection and side-scan sonar techniques to map its morphology and structure, and a near-bottom instrument system contributed to understanding present activity of the deposit. Seismic-reflection profiles show that the fine-grained deposit, which is as much as 13 m thick, has accumulated during the last transgression because it rests on a reflector that is geomorphically similar to and continuous with the Holocene transgressive sand sheet still exposed on the shelf to the west. The ridge and swale topography comprising the sand sheet on the shelf off New Jersey and Long Island are relict in origin as these same features are found buried under the fine sediment deposit. Southwestward migrating megaripples observed on the sonographs in the eastern part of the deposit are evidence that sediment is still actively accumulating in this area. In the western part of the deposit, where surface sediment is composed of silt plus clay, evidence of present sediment mobility consists of changes in the near-bottom, suspended-matter concentrations primarily associated with storms. Nantucket Shoals and Georges Bank are thought to be the sources for the fine-textured sediment. Storms and strong tidal currents in these shoal areas may still erode available fine-grained material, which then is transported westward by the mean drift to the southern New England Shelf, where a comparatively tranquil environment permits deposition of the fine material.

  10. Fractionation of metals in street sediment samples by using the BCR sequential extraction procedure and multivariate statistical elucidation of the data

    International Nuclear Information System (INIS)

    Kartal, Senol; Aydin, Zeki; Tokalioglu, Serife

    2006-01-01

    The concentrations of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in street sediment samples were determined by flame atomic absorption spectrometry (FAAS) using the modified BCR (the European Community Bureau of Reference) sequential extraction procedure. According to the BCR protocol for extracting the metals from the relevant target phases, 1.0 g of specimen of the sample was treated with 0.11 M acetic acid (exchangeable and bound to carbonates), 0.5 M hydroxylamine hydrochloride (bound to iron- and manganese-oxides), and 8.8 M hydrogen peroxide plus 1 M ammonium acetate (bound to sulphides and organics), sequentially. The residue was treated with aqua regia solution for recovery studies, although this step is not part of the BCR procedure. The mobility sequence based on the sum of the BCR sequential extraction stages was: Cd ∼ Zn (∼90%) > Pb (∼84%) > Cu (∼75%) > Mn (∼70%) > Co (∼57%) > Ni (∼43%) > Cr (∼40%) > Fe (∼17%). Enrichment factors as the criteria for examining the impact of the anthropogenic emission sources of heavy metals were calculated, and it was observed that the highest enriched elements were Cd, Pb, and Zn in the dust samples, average 190, 111, and 20, respectively. Correlation analysis (CA) and principal component analysis (PCA) were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. PCA revealed that the sampling area was mainly influenced from three pollution sources, namely; traffic, industrial, and natural sources. The results show that chemical sequential extraction is a precious operational tool. Validation of the analytical results was checked by both recovery studies and analysis of the standard reference material (NIST SRM 2711 Montana Soil)

  11. Sediment deposition and trends and transport of phosphorus and other chemical constituents, Cheney Reservoir watershed, south-central Kansas

    Science.gov (United States)

    Mau, D.P.

    2001-01-01

    Sediment deposition, water-quality trends, and mass transport of phosphorus, nitrogen, selected trace elements, and selected pesticides within the Cheney Reservoir watershed in south-central Kansas were investigated using bathymetric survey data and reservoir bottom-sediment cores. Sediment loads in the reservoir were investigated by comparing 1964 topographic data to 1998 bathymetric survey data. Approximately 7,100 acre-feet of sediment deposition occurred in Cheney Reservoir from 1965 through 1998. As of 1998, sediment had filled 27 percent of the reservoir's inactive conservation storage pool, which is less than the design estimate of 34 percent. Mean annual sediment deposition was 209 acre-feet per year, or 0.22 acre-feet per year per square mile, and the mean annual sediment load was 453 million pounds per year. During the 3-year period from 1997 through 1999, 23 sediment cores were collected from the reservoir, and subsamples were analyzed for nutrients (phosphorus and nitrogen species), selected trace elements, and selected organic pesticides. Mean concentrations of total phosphorus in reservoir bottom sediment ranged from 94 milligrams per kilogram at the upstream end of the reservoir to 710 milligrams per kilogram farther downstream near the reservoir dam. The mean concentration for all sites was 480 milligrams per kilogram. Total phosphorus concentrations were greatest when more silt- and clay-sized particles were present. The implications are that if anoxic conditions (inadequate oxygen) occur near the dam, phosphorus could be released from the sediment and affect the drinking-water supply. Analysis of selected cores also indicates that total phosphorus concentrations in the reservoir sediment increased over time and were probably the result of nonpoint-source activities in the watershed, such as increased fertilizer use and livestock production. Mean annual phosphorus loading to Cheney Reservoir was estimated to be 226,000 pounds per year on the basis

  12. The analyzing stratum formation and sediment environment using TEM for finding sandstone type uranium deposits in Mahuangquan area

    International Nuclear Information System (INIS)

    Zhao Xigang; He Jianguo; Zhao Cuiping; Lou Hansheng

    2010-01-01

    Transient electromagnetic method (TEM) is used to detect deep geological information for insidious sandstone type uranium deposits in Mahuangquan area. TEM surveying data is processed to build the relation between resistance rate and different petrology, to ensure three large electronic strata, and to explain the space position of sediment center and alluvial fan. Combining with ore control factors of sandstone type uranium deposit, it can conclude that the slope area and the alluvial fan are the key areas for further exploration work. (authors)

  13. Permeability of sediment cores from methane hydrate deposit in the Eastern Nankai Trough, Japan

    Science.gov (United States)

    Konno, Y.; Yoneda, J.; Egawa, K.; Ito, T.; Jin, Y.; Kida, M.; Suzuki, K.; Nakatsuka, Y.; Nagao, J.

    2013-12-01

    Effective and absolute permeability are key parameters for gas production from methane-hydrate-bearing sandy sediments. Effective and/or absolute permeability have been measured using methane-hydrate-bearing sandy cores and clayey and silty cores recovered from Daini Atsumi Knoll in the Eastern Nankai Trough during the 2012 JOGMEC/JAPEX Pressure coring operation. Liquid-nitrogen-immersed cores were prepared by rapid depressurization of pressure cores recovered by a pressure coring system referred to as the Hybrid PCS. Cores were shaped cylindrically on a lathe with spraying of liquid nitrogen to prevent hydrate dissociation. Permeability was measured by a flooding test or a pressure relaxation method under near in-situ pressure and temperature conditions. Measured effective permeability of hydrate-bearing sediments is less than tens of md, which are order of magnitude less than absolute permeability. Absolute permeability of clayey cores is approximately tens of μd, which would perform a sealing function as cap rocks. Permeability reduction due to a swelling effect was observed for a silty core during flooding test of pure water mimicking hydrate-dissociation-water. Swelling effect may cause production formation damage especially at a later stage of gas production from methane hydrate deposits. This study was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) that carries out Japan's Methane Hydrate R&D Program conducted by the Ministry of Economy, Trade and Industry (METI).

  14. Controls of tectonics and sediment source locations on along-strike variations in transgressive deposits on the northern California margin

    Science.gov (United States)

    Spinelli, G.A.; Field, M.E.

    2003-01-01

    We identify two surfaces in the shallow subsurface on the Eel River margin offshore northern California, a lowstand erosion surface, likely formed during the last glacial maximum, and an overlying surface likely formed during the most recent transgression of the shoreline. The lowstand erosion surface, which extends from the inner shelf to near the shelfbreak and from the Eel River to Trinidad Head (???80 km), truncates underlying strata on the shelf. Above the surface, inferred transgressive coastal and estuarine sedimentary units separate it from the transgressive surface on the shelf. Early in the transgression, Eel River sediment was likely both transported down the Eel Canyon and dispersed on the slope, allowing transgressive coastal sediment from the smaller Mad River to accumulate in a recognizable deposit on the shelf. The location of coastal Mad River sediment accumulation was controlled by the location of the paleo-Mad River. Throughout the remainder of the transgression, dispersed sediment from the Eel River accumulated an average of 20 m of onlapping shelf deposits. The distribution and thickness of these transgressive marine units was strongly modified by northwest-southeast trending folds. Thick sediment packages accumulated over structural lows in the lowstand surface. The thinnest sediment accumulations (0-10 m) were deposited over structural highs along faults and uplifting anticlines. The Eel margin, an active margin with steep, high sediment-load streams, has developed a thick transgressive systems tract. On this margin sediment accumulates as rapidly as the processes of uplift and downwarp locally create and destroy accommodation space. Sequence stratigraphic models of tectonically active margins should account for variations in accommodation space along margins as well as across them. ?? 2003 Elsevier Science B.V. All rights reserved.

  15. Spatial and temporal variability of sediment deposition on artificial-lawn traps in a floodplain of the River Elbe

    Energy Technology Data Exchange (ETDEWEB)

    Baborowski, M. [Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Brueckstrasse 3a, 39114 Magdeburg (Germany)]. E-mail: martina.baborowski@ufz.de; Buettner, O. [Department of Lake Research, Helmholtz Centre for Environmental Research - UFZ, Brueckstrasse 3a, 39114 Magdeburg (Germany); Morgenstern, P. [Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Krueger, F. [ELANA Boden Wasser Monitoring, Dorfstrasse 55, 39615 Falkenberg (Germany); Lobe, I. [Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Brueckstrasse 3a, 39114 Magdeburg (Germany); Rupp, H. [Department of Soil Physics, Helmholtz Centre for Environmental Research - UFZ, Dorfstrasse 55, 39615 Falkenberg (Germany); Tuempling, W. v. [Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Brueckstrasse 3a, 39114 Magdeburg (Germany)

    2007-08-15

    Artificial-lawn mats were used as sediment traps in floodplains to measure sediment input and composition during flood events. To estimate the natural variability, 10 traps were installed during two flood waves at three different morphological units in a meander loop of the River Elbe. The geochemical composition of deposited and suspended matter was compared. The sediment input showed weak correlations with concentration and composition of river water. It also correlated poorly with flood duration and level as well as distance of trap position from the main river. This is due to the high variability of the inundation, different morphological conditions and the variability of sources. The composition of the deposits and the suspended matter in the river water was comparable. Hence, for the investigated river reach, the expected pollution of the floodplain sediments can be derived from the pollution of the suspended matter in the river during the flood wave. - The deposition of polluted sediments on floodplains is characterised by a high local variability.

  16. Spatial and temporal variability of sediment deposition on artificial-lawn traps in a floodplain of the River Elbe

    International Nuclear Information System (INIS)

    Baborowski, M.; Buettner, O.; Morgenstern, P.; Krueger, F.; Lobe, I.; Rupp, H.; Tuempling, W. v.

    2007-01-01

    Artificial-lawn mats were used as sediment traps in floodplains to measure sediment input and composition during flood events. To estimate the natural variability, 10 traps were installed during two flood waves at three different morphological units in a meander loop of the River Elbe. The geochemical composition of deposited and suspended matter was compared. The sediment input showed weak correlations with concentration and composition of river water. It also correlated poorly with flood duration and level as well as distance of trap position from the main river. This is due to the high variability of the inundation, different morphological conditions and the variability of sources. The composition of the deposits and the suspended matter in the river water was comparable. Hence, for the investigated river reach, the expected pollution of the floodplain sediments can be derived from the pollution of the suspended matter in the river during the flood wave. - The deposition of polluted sediments on floodplains is characterised by a high local variability

  17. Response of stream-breeding salamander larvae to sediment deposition in southern Appalachian (U.S.A.) headwater streams

    Science.gov (United States)

    S. Conner Keitzer; Reuben. Goforth

    2012-01-01

    Summary 1. Increased fine sediment deposition is a prevalent threat to stream biodiversity and has been shown to impact stream-breeding salamanders negatively. However, their complex life histories make it difficult to determine which stage is affected. 2. We conducted field experiments from 26 August to 11 September 2010 and 11 October to 11...

  18. A coupled modelling effort to study the fate of contaminated sediments downstream of the Coles Hill deposit, Virginia, USA

    Directory of Open Access Journals (Sweden)

    C. F. Castro-Bolinaga

    2015-03-01

    Full Text Available This paper presents the preliminary results of a coupled modelling effort to study the fate of tailings (radioactive waste-by product downstream of the Coles Hill uranium deposit located in Virginia, USA. The implementation of the overall modelling process includes a one-dimensional hydraulic model to qualitatively characterize the sediment transport process under severe flooding conditions downstream of the potential mining site, a two-dimensional ANSYS Fluent model to simulate the release of tailings from a containment cell located partially above the local ground surface into the nearby streams, and a one-dimensional finite-volume sediment transport model to examine the propagation of a tailings sediment pulse in the river network located downstream. The findings of this investigation aim to assist in estimating the potential impacts that tailings would have if they were transported into rivers and reservoirs located downstream of the Coles Hill deposit that serve as municipal drinking water supplies.

  19. Fine-grained sediment deposition on mussel beds in the Oosterschelde (The Netherlands), determined from echosoundings, radio-isotopes and biodeposition field experiments

    International Nuclear Information System (INIS)

    Brinke, W.B.M. ten; Augustinus, P.G.E.F.

    1995-01-01

    Sedimentation rates of 5-20 cm year -1 were calculated from 137 Cs + 134 Cs activity profiles and echosoundings in a mussel cultivation area in the western part of the Oosterschelde. Sedimentation rates based on 210 Pb activity profiles are far too low, mainly due to the deposition of 'aged' sediment, i.e. sediment eroded elsewhere inside the basin and not fully enriched with 210 Pb at the moment of deposition. Also, specific adsorption to the finest sediment components, mixing, winnowing, and mobilization of the caesium have affected the lead and caesium profiles. Field experiments on mussel plots showed that mussels deposit 5-10 cm of fine-grained sediment during the summer. This biodeposition about equals the settling from flocculation in the water column. Micro-fabric microscope studies revealed that pellets do not dominate the sediments, indicating that some of the pellets are broken down or resuspended. (author)

  20. Heavy metal contents of road-deposited sediment along the urban-rural gradient around Beijing and its potential contribution to runoff pollution.

    Science.gov (United States)

    Zhao, Hongtao; Li, Xuyong; Wang, Xiaomei

    2011-09-01

    Understanding the contribution of road-deposited sediment (RDS) and its washoff process is essential for controlling urban runoff pollution. Ninety-seven RDS samples were collected along the urban-suburban-rural gradient from areas of five administrative units in the Beijing metropolitan region, including central urban (UCA), urban village (UVA), central suburban county (CSA), rural town (RTA), and rural village (RVA) areas. RDS washoff was evaluated with different particle sizes using a rainfall simulator. Heavy metal elements (i.e., Cr, Cu, Ni, Pb, and Zn) were estimated in both RDS and runoff samples. The RDS mass per unit area increased in the order UCA (21 ± 24 g/m(2)) ≈ CSA (20 ± 16 g/m(2)) runoff pollution contributions per unit area. Our findings imply that controlling the first flush in the UCA and CSA, and improving existing street cleaning methods and road surface conditions in the TRA, UVA, and RVA will be appropriate strategies for controlling runoff pollution from RDS.

  1. Street Politics

    Directory of Open Access Journals (Sweden)

    Michael J. Shapiro

    2012-03-01

    Full Text Available I write from Prague, where, unlike in most urban formations, the main city street plays an iconic role; it references a history of political protest. However, before elaborating on the protest iconography of the Prague street, Vaclavske nam, I want to locate the ways in which the design of urban space is actualized in everyday life in the cities of the world. Three functions stand out; the first involves dwelling, the second seeing, and the third moving. With respect to the first function – dwelling – the design partitions and coordinates residential, commercial and leisure functions. At times these are organized to segregate different classes (Robert Moses’ redesign of much of New York stands out with respect to the segregation function. With respect to the second function – seeing – the design of urban space is allegiance-inspiring; it involves sight lines that afford urban dwellers and visitors views of iconic buildings and statues, which reference key founding moments in the past and/or authoritative political functions in the present (Here, L’Enfants design for Washington DC stands out as exemplary. Its manifest intention was to make the buildings housing executive, legislative and judicial functions visible from many vantage points. Rarely are the streets themselves iconic. Their dominant role is involved with the effectuation of movement. As for this third function: As Lewis Mumford famously points out, streets were once part of an asterisk design, radiating out from an exemplary, often spiritual center...

  2. Age, distribution, and significance within a sediment budget, of in-channel depositional surfaces in the Normanby River, Queensland, Australia

    Science.gov (United States)

    Pietsch, T. J.; Brooks, A. P.; Spencer, J.; Olley, J. M.; Borombovits, D.

    2015-06-01

    We present the results of investigations into alluvial deposition in the catchment of the Normanby River, which flows into Princess Charlotte Bay (PCB) in the northern part of the Great Barrier Reef Lagoon. Our focus is on the fine fraction (bank attached bars or inset or inner floodplains, these more or less flat-lying surfaces within the macro-channel have hitherto received little attention in sediment budgeting models. We use high resolution LiDAR based mapping combined with optical dating of exposures cut into these in-channel deposits to compare their aggradation rates with those found in other depositional zones in the catchment, namely the floodplain and coastal plain. In total 59 single grain OSL dates were produced across 21 stratigraphic profiles at 14 sites distributed though the 24 226 km2 catchment. In-channel storage in these inset features is a significant component of the contemporary fine sediment budget (i.e. recent decades/last century), annually equivalent to more than 50% of the volume entering the channel network from hillslopes and subsoil sources. Therefore, at the very least, in-channel storage of fine material needs to be incorporated into sediment budgeting exercises. Furthermore, deposition within the channel has occurred in multiple locations coincident in time with accelerated sediment production following European settlement. Generally, this has occurred on a subset of the features we have examined here, namely linear bench features low in the channel. This suggests that accelerated aggradation on in-channel depositional surfaces has been in part a response to accelerated erosion within the catchment. The entire contribution of ~ 370 kilotonnes per annum of fine sediment estimated to have been produced by alluvial gully erosion over the last ~ 100 years can be accounted for by that stored as in-channel alluvium. These features therefore can play an important role in mitigating the impact on the receiving water of accelerated erosion.

  3. Long-Term Impact of Sediment Deposition and Erosion on Water Surface Profiles in the Ner River

    Directory of Open Access Journals (Sweden)

    Tomasz Dysarz

    2017-02-01

    Full Text Available The purpose of the paper is to test forecasting of the sediment transport process, taking into account two main uncertainties involved in sediment transport modeling. These are: the lack of knowledge regarding future flows, and the uncertainty with respect to which sediment transport formula should be chosen for simulations. The river reach chosen for study is the outlet part of the Ner River, located in the central part of Poland. The main characteristic of the river is the presence of an intensive morphodynamic process, increasing flooding frequency. The approach proposed here is based on simulations with a sediment-routing model and assessment of the hydraulic condition changes on the basis of hydrodynamic calculations for the chosen characteristic flows. The data used include Digital Terrain Models (DTMs, cross-section measurements, and hydrological observations from the Dabie gauge station. The sediment and hydrodynamic calculations are performed using program HEC-RAS 5.0. Twenty inflow scenarios are of a 10-year duration and are composed on the basis of historical data. Meyer-Peter and Müller and Engelund-Hansen formulae are applied for the calculation of sediment transport intensity. The methodology presented here seems to be a good tool for the prediction of long-term impacts on water surface profiles caused by sediment deposition and erosion.

  4. Trends in historical mercury deposition inferred from lake sediment cores across a climate gradient in the Canadian High Arctic.

    Science.gov (United States)

    Korosi, Jennifer B; Griffiths, Katherine; Smol, John P; Blais, Jules M

    2018-06-02

    Recent climate change may be enhancing mercury fluxes to Arctic lake sediments, confounding the use of sediment cores to reconstruct histories of atmospheric deposition. Assessing the independent effects of climate warming on mercury sequestration is challenging due to temporal overlap between warming temperatures and increased long-range transport of atmospheric mercury following the Industrial Revolution. We address this challenge by examining mercury trends in short cores (the last several hundred years) from eight lakes centered on Cape Herschel (Canadian High Arctic) that span a gradient in microclimates, including two lakes that have not yet been significantly altered by climate warming due to continued ice cover. Previous research on subfossil diatoms and inferred primary production indicated the timing of limnological responses to climate warming, which, due to prevailing ice cover conditions, varied from ∼1850 to ∼1990 for lakes that have undergone changes. We show that climate warming may have enhanced mercury deposition to lake sediments in one lake (Moraine Pond), while another (West Lake) showed a strong signal of post-industrial mercury enrichment without any corresponding limnological changes associated with warming. Our results provide insights into the role of climate warming and organic carbon cycling as drivers of mercury deposition to Arctic lake sediments. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Response of PAH-degrading genes to PAH bioavailability in the overlying water, suspended sediment, and deposited sediment of the Yangtze River.

    Science.gov (United States)

    Xia, Xinghui; Xia, Na; Lai, Yunjia; Dong, Jianwei; Zhao, Pujun; Zhu, Baotong; Li, Zhihuang; Ye, Wan; Yuan, Yue; Huang, Junxiong

    2015-06-01

    The degrading genes of hydrophobic organic compounds (HOCs) serve as indicators of in situ HOC degradation potential, and the existing forms and bioavailability of HOCs might influence the distribution of HOC-degrading genes in natural waters. However, little research has been conducted to study the relationship between them. In the present study, nahAc and nidA genes, which act as biomarkers for naphthalene- and pyrene-degrading bacteria, were selected as model genotypes to investigate the response of polycyclic aromatic hydrocarbon (PAH)-degrading genes to PAH bioavailability in the overlying water, suspended sediment (SPS), and deposited sediment of the Yangtze River. The freely dissolved concentration, typically used to reflect HOC bioavailability, and total dissolved, as well as sorbed concentrations of PAHs were determined. Phylogenetic analysis showed that all the PAH-ring hydroxylating dioxygenase gene sequences of Gram-negative bacteria (PAH-RHD[GN]) were closely related to nahAc, nagAc, nidA, and uncultured PAH-RHD genes. The PAH-RHD[GN] gene diversity as well as nahAc and nidA gene copy numbers decreased in the following order: deposited sediment>SPS>overlying water. The nahAc and nidA gene abundance was not significantly correlated with environmental parameters but was significantly correlated with the bioavailable existing forms of naphthalene and pyrene in the three phases. The nahAc gene copy numbers in the overlying water and deposited sediment were positively correlated with freely dissolved naphthalene concentrations in the overlying and pore water phases, respectively, and so were nidA gene copy numbers. This study suggests that the distribution and abundance of HOC-degrading bacterial population depend on the HOC bioavailability in aquatic environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. On the effect of cross sectional shape on incipient motion and deposition of sediments in fixed bed channels

    Directory of Open Access Journals (Sweden)

    Safari Mir-Jafar-Sadegh

    2014-03-01

    Full Text Available The condition of incipient motion and deposition are of the essential issues for the study of sediment transport. This phenomenon is of great importance to hydraulic engineers for designing sewers, drainage, as well as other rigid boundary channels. This is a study carried out with the objectives of describing the effect of cross-sectional shape on incipient motion and deposition of particles in rigid boundary channels. In this research work, the experimental data given by Loveless (1992 and Mohammadi (2005 are used. On the basis of the critical velocity approach, a new incipient motion equation for a V-shaped bottom channel and incipient deposition of sediment particles equations for rigid boundary channels having circular, rectangular, and U-shaped cross sections are obtained. New equations were compared to the other incipient motion equations. The result shows that the cross-sectional shape is an important factor for defining the minimum velocity for no-deposit particles. This study also distinguishes incipient motion of particles from incipient deposition for particles. The results may be useful for designing fixed bed channels with a limited deposition condition.

  7. Sediment and carbon deposition vary among vegetation assemblages in a coastal salt marsh

    Directory of Open Access Journals (Sweden)

    J. J. Kelleway

    2017-08-01

    Full Text Available Coastal salt marshes are dynamic, intertidal ecosystems that are increasingly being recognised for their contributions to ecosystem services, including carbon (C accumulation and storage. The survival of salt marshes and their capacity to store C under rising sea levels, however, is partially reliant upon sedimentation rates and influenced by a combination of physical and biological factors. In this study, we use several complementary methods to assess short-term (days deposition and medium-term (months accretion dynamics within a single marsh that contains three salt marsh vegetation types common throughout southeastern (SE Australia.We found that surface accretion varies among vegetation assemblages, with medium-term (19 months bulk accretion rates in the upper marsh rush (Juncus assemblage (1.74 ± 0.13 mm yr−1 consistently in excess of estimated local sea-level rise (1.15 mm yr−1. Accretion rates were lower and less consistent in both the succulent (Sarcocornia, 0.78 ± 0.18 mm yr−1 and grass (Sporobolus, 0.88 ± 0.22 mm yr−1 assemblages located lower in the tidal frame. Short-term (6 days experiments showed deposition within Juncus plots to be dominated by autochthonous organic inputs with C deposition rates ranging from 1.14 ± 0.41 mg C cm−2 d−1 (neap tidal period to 2.37 ± 0.44 mg C cm−2 d−1 (spring tidal period, while minerogenic inputs and lower C deposition dominated Sarcocornia (0.10 ± 0.02 to 0.62 ± 0.08 mg C cm−2 d−1 and Sporobolus (0.17 ± 0.04 to 0.40 ± 0.07 mg C cm−2 d−1 assemblages.Elemental (C : N, isotopic (δ13C, mid-infrared (MIR and 13C nuclear magnetic resonance (NMR analyses revealed little difference in either the source or character of materials being deposited among neap versus spring tidal periods. Instead, these analyses point to substantial redistribution of materials within the Sarcocornia and

  8. Origin and depositional environment of fine-grained sediments since the last glacial maximum in the southeastern Yellow Sea: evidence from rare earth elements

    Science.gov (United States)

    Um, In Kwon; Choi, Man Sik; Lee, Gwang Soo; Chang, Tae Soo

    2015-12-01

    Despite the well-reconstructed seismic stratigraphy of the Holocene mud deposit in the southeastern Yellow Sea, known as the Heuksan mud belt (HMB), the provenances of these sediments and their depositional environments are unclear, especially for the fine-grained sediments. According to seismic data (extracted from another article in this special issue), the HMB comprises several sedimentary units deposited since the last glacial maximum. Based on analytical results on rare earth elements, fine-grained sediments in all sedimentary units can be interpreted as mixtures of sediments discharged from Chinese and Korean rivers. The proportions of fine-grained sediments from Chinese rivers (74.5 to 80.0%) were constant and higher than those from Korean rivers in all units. This fact demonstrates that all units have the same fine-grained sediment provenance: units III-b and III-a, located in the middle and northern parts of the HMB and directly deposited from Chinese rivers during the sea-level lowstand, could be the sediment source for units II-b and II-a. Unit I, while ambiguous, is of mixed origin combining reworked sediments from nearby mud deposits and Changjiang River-borne material with those of the Keum River. The results of this study indicate that at least 18.6% of bulk sediments in the HMB clearly originate from Chinese rivers, despite its location close to the southwestern coast of Korea.

  9. ASSESSMENT OF THE CHEMICAL POLLUTION OF THE SOIL, GROUND AND BOTTOM SEDIMENTS AT KLEN GOLD AND SILVER DEPOSIT

    Directory of Open Access Journals (Sweden)

    Bryukhan' Fedor Fedorovich

    2012-10-01

    Full Text Available Currently, prospecting and design-related works are performed prior to the upcoming launch of mining operations at Klen gold and silver deposit in Chukot Autonomous District. The anthropogenic impact of the geological exploration in this intact territory has been produced since 1984. A considerable amount of borehole drilling, prospecting, road building, and temporary housing development has been performed. The engineering research, including ecological surveys, has been completed to assess the ecological impact of upcoming exploratory and mining operations at the deposit. Assessment of the geochemical condition of the landscape constituents, including the soil, ground and bottom sediments is of special importance in terms of their engineering protection and rational management of the natural environment. The above assessments were based on the field sampling made by «Sibgeoconsulting», CJSC (Krasnoyarsk and the laboratory research made by accredited laboratories of Federal State Unitary Geological Enterprise «Urangeolograzvedka» (Irkutsk and «Krasnoyarskgeologiya» (Krasnoyarsk. The analysis of the chemical pollution of soils, ground and bottom sediments is based on the examination of 30 samples. Peculiarities of the chemical composition of samples extracted at the deposit were identified. It has been discovered that pH values of the soil vary from 5.1 to 7.3. The concentration of metal in bottom sediments exceeds its concentration in the soil by far. Almost all irregular features of the sample water in the whole territory of the deposit are caused by the anthropogenic impact. In general, the metal content in soils, ground and bottom sediments within the territory of the deposit is slightly different from the regular clarke.

  10. Metalliferous sediment and a silica-hematite deposit within the Blanco fracture zone, Northeast Pacific

    Science.gov (United States)

    Hein, J.R.; Clague, D.A.; Koski, R.A.; Embley, R.W.; Dunham, R.E.

    2008-01-01

    A Tiburon ROV dive within the East Blanco Depression (EBD) increased the mapped extent of a known hydrothermal field by an order of magnitude. In addition, a unique opal-CT (cristobalite-tridymite)-hematite mound was discovered, and mineralized sediments and rock were collected and analyzed. Silica-hematite mounds have not previously been found on the deep ocean floor. The light-weight rock of the porous mound consists predominantly of opal-CT and hematite filaments, rods, and strands, and averages 77.8% SiO2 and 11.8% Fe2O3. The hematite and opal-CT precipitated from a low-temperature (???115?? C), strongly oxidized, silica- and iron-rich, sulfur-poor hydrothermal fluid; a bacterial mat provided the framework for precipitation. Samples collected from a volcaniclastic rock outcrop consist primarily of quartz with lesser plagioclase, smectite, pyroxene, and sulfides; SiO2 content averages 72.5%. Formation of these quartz-rich samples is best explained by cooling in an up-flow zone of silica-rich hydrothermal fluids within a low permeability system. Opal-A, opal-CT, and quartz mineralization found in different places within the EBD hydrothermal field likely reflects decreasing silica saturation and increasing temperature of the mineralizing fluid with increasing silica crystallinity. Six push cores recovered gravel, coarse sand, and mud mineralized variously by Fe or Mn oxides, silica, and sulfides. Total rare-earth element concentrations are low for both the rock and push core samples. Ce and Eu anomalies reflect high and low temperature hydrothermal components and detrital phases. A remarkable variety of types of mineralization occur within the EBD field, yet a consistent suite of elements is enriched (relative to basalt and unmineralized cores) in all samples analyzed: Ag, Au, S, Mo, Hg, As, Sb, Sr, and U; most samples are also enriched in Cu, Pb, Cd, and Zn. On the basis of these element enrichments, the EBD hydrothermal field might best be described as a base

  11. The Deposition and Accumulation of Microplastics in Marine Sediments and Bottom Water from the Irish Continental Shelf.

    Science.gov (United States)

    Martin, Jake; Lusher, Amy; Thompson, Richard C; Morley, Audrey

    2017-09-07

    Microplastics are widely dispersed throughout the marine environment. An understanding of the distribution and accumulation of this form of pollution is crucial for gauging environmental risk. Presented here is the first record of plastic contamination, in the 5 mm-250 μm size range, of Irish continental shelf sediments. Sixty-two microplastics were recovered from 10 of 11 stations using box cores. 97% of recovered microplastics were found to reside shallower than 2.5 cm sediment depth, with the area of highest microplastic concentration being the water-sediment interface and top 0.5 cm of sediments (66%). Microplastics were not found deeper than 3.5 ± 0.5 cm. These findings demonstrate that microplastic contamination is ubiquitous within superficial sediments and bottom water along the western Irish continental shelf. Results highlight that cores need to be at least 4-5 cm deep to quantify the standing stock of microplastics within marine sediments. All recovered microplastics were classified as secondary microplastics as they appear to be remnants of larger items; fibres being the principal form of microplastic pollution (85%), followed by broken fragments (15%). The range of polymer types, colours and physical forms recovered suggests a variety of sources. Further research is needed to understand the mechanisms influencing microplastic transport, deposition, resuspension and subsequent interactions with biota.

  12. Sedimentation

    Science.gov (United States)

    Cliff R. Hupp; Michael R. Schening

    2000-01-01

    Sedimentation is arguably the most important water-quality concern in the United States. Sediment trapping is cited frequently as a major function of riverine-forested wetlands, yet little is known about sedimcntation rates at the landscape scale in relation to site parameters, including woody vegetation type, elevation, velocity, and hydraulic connection to the river...

  13. Earthquake-induced soft-sediment deformation structures in Late Pleistocene lacustrine deposits of Issyk-Kul lake (Kyrgyzstan)

    Science.gov (United States)

    Gladkov, A. S.; Lobova, E. U.; Deev, E. V.; Korzhenkov, A. M.; Mazeika, J. V.; Abdieva, S. V.; Rogozhin, E. A.; Rodkin, M. V.; Fortuna, A. B.; Charimov, T. A.; Yudakhin, A. S.

    2016-10-01

    This paper discusses the composition and distribution of soft-sediment deformation structures induced by liquefaction in Late Pleistocene lacustrine terrace deposits on the southern shore of Issyk-Kul Lake in the northern Tien Shan mountains of Kyrgyzstan. The section contains seven deformed beds grouped in two intervals. Five deformed beds in the upper interval contain load structures (load casts and flame structures), convolute lamination, ball-and-pillow structures, folds and slumps. Deformation patterns indicate that a seismic trigger generated a multiple slump on a gentle slope. The dating of overlying subaerial deposits suggests correlation between the deformation features and strong earthquakes in the Late Pleistocene.

  14. Modelling post-depositional transport of PAHs in aquatic bed sediments using CoReTranS

    Energy Technology Data Exchange (ETDEWEB)

    Go, Jason [Imperial College London, London (United Kingdom). Dept. of Earth Science and Engineering; Stegemann, Julia A. [Imperial College London, London (United Kingdom). Dept. of Civil, Environmental and Geomatic Engineering

    2012-12-15

    Purpose: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous and persistent contaminants in aquatic bed sediments. A better understanding of their in-bed fate and transport is therefore key in minimising the risk to the environment over time through various remediation and monitoring strategies. Since ecological effects and risks are related to contaminant concentrations, this study developed CoReTranS, a predictive model that simulates one-dimensional organic contaminant reaction and transport in bed sediments. Materials and methods: CoReTranS was benchmarked against analytical solutions of simplified reactive transport models and validated using a published study of marsh sediments contaminated with petroleum-derived hydrocarbons from Wild Harbour, West Falmouth, MA, USA. Results and discussion: The CoReTranS model effectively predicted the vertical distribution of PAHs in the Wild Harbour sediments as confirmed by the modelling results from the published study. The CoReTranS model was also used to interpret results from a published study of PAH-contaminated fjord sediments from Kitimat Arm in British Columbia, Canada. Specific insights into the post-depositional fate and transport of selected PAHs in the Kitimat fjord sediments were obtained by comparing the measured concentration-depth profiles with the numerical results from the CoReTranS model. Key parameters such as effective diffusivity of contaminants and burial velocities of sediment particles were shown to possibly account for the predicted concentrations-depth profiles in the Kitimat fjord sediments. Conclusions: As demonstrated, CoReTranS can simulate reactive transport models in order to predict PAH concentration profiles in porewater under site-specific conditions. The information derived from the use of the CoReTranS model highlighted practical application of such information by engineers to site-specific risk assessment and remediation. (orig.)

  15. Particle size distribution and characteristics of heavy metals in road-deposited sediments from Beijing Olympic Park.

    Science.gov (United States)

    Li, Haiyan; Shi, Anbang; Zhang, Xiaoran

    2015-06-01

    Due to rapid urbanization and industrialization, heavy metals in road-deposited sediments (RDSs) of parks are emitted into the terrestrial, atmospheric, and water environment, and have a severe impact on residents' and tourists' health. To identify the distribution and characteristic of heavy metals in RDS and to assess the road environmental quality in Chinese parks, samples were collected from Beijing Olympic Park in the present study. The results indicated that particles with small grain size (Pb>Cu>Zn. This study analyzed the mobility of heavy metals in sediments using partial sequential extraction with the Tessier procedure. The results revealed that the apparent mobility and potential metal bioavailability of heavy metals in the sediments, based on the exchangeable and carbonate fractions, decreased in the order: Cd>Zn≈Pb>Cu. Copyright © 2015. Published by Elsevier B.V.

  16. Effects of terrestrial and marine organic matters on deposition of dechlorane plus (DP) in marine sediments from the Southern Yellow Sea, China: Evidence from multiple biomarkers

    International Nuclear Information System (INIS)

    Wang, Guoguang; Peng, Jialin; Hao, Ting; Feng, Lijuan; Liu, Qiaoling; Li, Xianguo

    2017-01-01

    As an emerging halogenated organic contaminant, Dechlorane Plus (DP) was scarcely reported in marine environments, especially in China. In this work, 35 surface sediments and a sediment core were collected across the Southern Yellow Sea (SYS) to comprehensively explore the spatio-temporal distribution and possible migration pathway of DP. DP concentrations ranged from 14.3 to 245.5 pg/g dry weight in the surface sediments, displaying a seaward increasing trend with the high levels in the central mud zone. This spatial distribution pattern was ascribed to that fine particles with the elevated DP levels were preferentially transported to the central mud zone under hydrodynamic forcing and/or via long-range atmospheric transportation and deposition. DP concentrations in sediment core gradually increased from the mid-1950s to present, which corresponded well with the historical production and usage of DP, as well as the economic development in China. Significantly positive correlation between DP and total organic carbon (TOC) in both surface sediments and sediment core indicated TOC-dependent natural deposition of DP in the SYS. We used multiple biomarkers, for the first time, to explore the potential effects of terrestrial and marine organic matters (TOM and MOM) on DP deposition. The results showed that competition may occur between TOM and MOM for DP adsorption, and MOM was the predominant contributor in controlling DP deposition in the marine sediments from the SYS. - Highlights: • Effects of TOM and MOM on DP deposition were first explored by multi-biomarkers. • Hydrodynamic forcing and atmospheric deposition were responsible for DP in the SYS. • MOM was the predominant contributor in controlling DP deposition to sediments in the SYS. • Competition may occur between TOM and MOM for DP adsorption. - This study was the first attempt to comprehensively explore the effects of TOM and MOM on DP deposition in marine sediments from the SYS.

  17. Reduction of non-point source contaminants associated with road-deposited sediments by sweeping.

    Science.gov (United States)

    Kim, Do-Gun; Kang, Hee-Man; Ko, Seok-Oh

    2017-09-19

    Road-deposited sediments (RDS) on an expressway, residual RDS collected after sweeping, and RDS removed by means of sweeping were analyzed to evaluate the degree to which sweeping removed various non-point source contaminants. The total RDS load was 393.1 ± 80.3 kg/km and the RDS, residual RDS, and swept RDS were all highly polluted with organics, nutrients, and metals. Among the metals studied, Cu, Zn, Pb, Ni, Ca, and Fe were significantly enriched, and most of the contaminants were associated with particles within the size range from 63 μm to 2 mm. Sweeping reduced RDS and its associated contaminants by 33.3-49.1% on average. We also measured the biological oxygen demand (BOD) of RDS in the present work, representing to our knowledge the first time that this has been done; we found that RDS contains a significant amount of biodegradable organics and that the reduction of BOD by sweeping was higher than that of other contaminants. Significant correlations were found between the contaminants measured, indicating that the organics and the metals originated from both exhaust and non-exhaust particles. Meanwhile, the concentrations of Cu and Ni were higher in 63 μm-2 mm particles than in smaller particles, suggesting that some metals in RDS likely exist intrinsically in particles, rather than only as adsorbates on particle surfaces. Overall, the results in this study showed that sweeping to collect RDS can be a good alternative for reduction of contaminants in runoff.

  18. Heavy metals in the finest size fractions of road-deposited sediments.

    Science.gov (United States)

    Lanzerstorfer, Christof

    2018-08-01

    The concentration of heavy metals in urban road-deposited sediments (RDS) can be used as an indicator for environmental pollution. Thus, their occurrence has been studied in whole road dust samples as well as in size fractions obtained by sieving. Because of the limitations of size separation by sieving little information is available about heavy metal concentrations in the road dust size fractions heavy metals concentrations and size distribution. According to the Geoaccumulation Index the pollution of the road dust samples deceased in the following order: Sb » As > Cu ≈ Zn > Cr > Cd ≈ Pb ≈ Mn > Ni > Co ≈ V. For all heavy metals the concentration was higher in the fine size fractions compared to the coarse size fractions, while the concentration of Sr was size-independent. The enrichment of the heavy metals in the finest size fraction compared to the whole RDS  Sb > (Cu) ≈ Zn ≈ Pb > As ≈ V » Mn. The approximation of the size dependence of the concentration as a function of the particle size by power functions worked very well. The correlation between particle size and concentration was high for all heavy metals. The increased heavy metals concentrations in the finest size fractions should be considered in the evaluation of the contribution of road dust re-suspension to the heavy metal contamination of atmospheric dust. Thereby, power functions can be used to describe the size dependence of the concentration. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Atmospheric deposition, water-quality, and sediment data for selected lakes in Mount Rainer, North Cascades, and Olympic National Parks, Washington, 2008-10

    Science.gov (United States)

    Sheibley, Rich W.; Foreman, James R.; Moran, Patrick W.; Swarzenski, Peter W.

    2012-01-01

    To evaluate the potential effect from atmospheric deposition of nitrogen to high-elevation lakes, the U.S. Geological Survey partnered with the National Park Service to develop a "critical load" of nitrogen for sediment diatoms. A critical load is defined as the level of a given pollutant (in this case, nitrogen) at which detrimental effects to a target endpoint (sediment diatoms) result. Because sediment diatoms are considered one of the "first responders" to ecosystem changes from nitrogen, they are a sensitive indicator for nitrogen deposition changes in natural areas. This report presents atmospheric deposition, water quality, sediment geochronology, and sediment diatom data collected from July 2008 through August 2010 in support of this effort.

  20. Simple street tree sampling

    Science.gov (United States)

    David J. Nowak; Jeffrey T. Walton; James Baldwin; Jerry. Bond

    2015-01-01

    Information on street trees is critical for management of this important resource. Sampling of street tree populations provides an efficient means to obtain street tree population information. Long-term repeat measures of street tree samples supply additional information on street tree changes and can be used to report damages from catastrophic events. Analyses of...

  1. Isotopic data from proterozoic sediment-hosted sulfide deposits of Brazil: Implications for their metallogenic evolution and for mineral exploration

    International Nuclear Information System (INIS)

    Misi, Aroldo; Coelho, Carlos E.S.; Franca Rocha, Washington J.S.; Gomez, Adriana S.R.; Cunha, Iona A.; Iyer, Sundaram S.; Tassinari, Colombo C.G.; Kyle, J. Richard

    1998-01-01

    Geological, petrographic, fluid inclusions studies and isotopic data of seven Proterozoic sediment-hosted Pb-Zn-Ag sulfide deposits of Brazil, permit the estimation of the age of the hosting sequence and the mineralization, the nature of the sulfur and metal sources, the temperature range of sulfide formation and the environment of deposition of the mineral deposits. The studies suggest that they were formed during periods of extensional tectonics: Growth faults or reactivated basement faults were responsible for localized circulation of metal-bearing fluids within the sedimentary sequences. In most cases, sulfides were formed by the reduction of sedimentary sulfates. Linear structures are important controls for sulfide concentration in these Proterozoic basins. (author)

  2. Distributing Characteristics of Heavy Metal Elements in A Tributary of Zhedong River in Laowangzhai Gold Deposit, Yunnan (China): An Implication to Environmentology from Sediments

    Science.gov (United States)

    Yang, Shuran; Danĕk, Tomáš; Yang, Xiaofeng; Cheng, Xianfeng

    2016-10-01

    Five heavy metal contents from five sediments and seven sediment profiles in an upstream reach of Zhedong river in Laowangzhai gold deposit were investigated in this research, along with analysis of the horizontal distribution, the surface distribution, the vertical distribution and the interlayer distribution of five heavy metal contents: arsenic (As), mercury (Hg), copper (Cu), lead (Pb) and zinc (Zn). The potential ecological risk of five heavy metals was evaluated to help understanding pollution control of Laowangzhai deposit.

  3. Short-term assessment of the sediment deposition rate and water conditions during a rainy season on La Azufrada coral reef, Gorgona Island, Colombia

    KAUST Repository

    Lozano-Corté s, Diego F; Giraldo, Alan; Izquierdo, Vanessa

    2014-01-01

    .60±0.52, respectively. Fourteen taxonomic groups of invertebrates were detected inside the sediment traps with bivalves and copepods being the most abundant and frequen. The findings presented here constitute the first report of both the potential sediment deposition

  4. Textural characteristics and sedimentary environment of sediment at eroded and deposited regions in the severely eroded coastline of Batu Pahat, Malaysia.

    Science.gov (United States)

    Wan Mohtar, Wan Hanna Melini; Nawang, Siti Aminah Bassa; Abdul Maulud, Khairul Nizam; Benson, Yannie Anak; Azhary, Wan Ahmad Hafiz Wan Mohamed

    2017-11-15

    This study investigates the textural characteristics of sediments collected at eroded and deposited areas of highly severed eroded coastline of Batu Pahat, Malaysia. Samples were taken from systematically selected 23 locations along the 67km stretch of coastline and are extended to the fluvial sediments of the main river of Batu Pahat. Grain size distribution analysis was conducted to identify its textural characteristics and associated sedimentary transport behaviours. Sediments obtained along the coastline were fine-grained material with averaged mean size of 7.25 ϕ, poorly sorted, positively skewed and has wide distributions. Samples from eroded and deposition regions displayed no distinctive characteristics and exhibited similar profiles. The high energy condition transported the sediments as suspension, mostly as pelagic and the sediments were deposited as shallow marine and agitated deposits. The fluvial sediments of up to 3km into the river have particularly similar profile of textural characteristics with the neighbouring marine sediments from the river mouth. Profiles were similar with marine sediments about 3km opposite the main current and can go up to 10km along the current of Malacca Straits. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Transport and deposition of plutonium in the ocean: Evidence from Gulf of Mexico sediments

    International Nuclear Information System (INIS)

    Scott, M.R.; Salter, P.F.; Halverson, J.E.

    1983-01-01

    A study of sediments in the Gulf of Mexico shows dramatic gradients in Pu content and isotope ratios from the continental shelf to the Sigsbee Abyssal Plain. In terms of predicted direct fallout inventory of Pu, one shelf core contains 745% of the predicted inventory, while abyssal plain sediments contain only 15-20% of the predicted value. Absolute Pu concentrations of shelf sediments are also conspicuously high, up to 110 dpm/kg, compared to 13.5 dpm/kg in Mississippi River suspended sediment. There is no evidence of Pu remobilization in Gulf of Mexico shelf sediments, based on comparison of Pu profiles with Mn/Al and Fe/Al profiles. Horizontal transport of fallout nuclides from the open ocean to removal sites in ocean margin sediments is concluded to be the source of both the high concentrations and high inventories of Pu reported here. The shelf sediments show 240 Pu/ 239 Pu ratios close to 0.179, the average stratospheric fallout value, but the ratios decrease progressively across the Gulf to low values of 0.06 in abyssal plain sediments. The source of low-ratio Pu in deep-water sediments may be debris from low yield tests transported in the troposphere. Alternatively, it may represent a fraction of the Pu from global stratospheric fallout which has been separated in the water column from the remainder of the Pu in the ocean. In either case, the low-ratio material must have been removed rapidly to the sea floor where it composes a major fraction of the Pu in abyssal plain sediments. Pu delivered by global atmospheric fallout from the stratosphere has apparently remained for the most part in the water or has been transported horizontally and removed into shallow-water sediments. (orig.)

  6. Turbidity current hydraulics and sediment deposition in erodible sinuous channels: Laboratory experiments and numerical simulations

    NARCIS (Netherlands)

    Janocko, M.; Cartigny, M.J.B.; Nemec, W.; Hansen, E.W.M.

    2013-01-01

    This study explores the relationship between the hydraulics of turbidity currents in erodible sinuous channels and the resulting intra-channel sediment depocentres (channel bars). Four factors are considered to exert critical control on sedimentation in sinuous submarine channels: (1) the

  7. Observations on sediment sources in the Lower Athabasca River basin: implications of natural hydrocarbons inputs from oil sands deposits

    International Nuclear Information System (INIS)

    Conly, F.M.

    1999-01-01

    Government, industry and public concern exists over the environmental consequences of the development of the oil sand deposits in the McMurray Formation in the lower Athabasca River basin, Alberta. The impact of this development is unclear and is undergoing investigation. Investigations to date have focussed on the nature of the effluent produced by the extraction industry and its effect on biotic systems, and on the spatial distribution of hydrocarbon contaminants associated with deposited fluvial sediments. Natural hydrocarbon outcrops may be responsible for observed biomarker responses in areas not exposed to industrial effluent. Given this source of hydrocarbons and doubt concerning its environmental impact, it is difficult to ascertain the impact of oil extraction activities within a fluvial system. A study was conducted to determine the nature and extent of natural hydrocarbon releases within the context of the sediment regime of the lower Athabasca River basin. A description is included of observations from the field and a context is set up for assessing sediment-bound hydrocarbon contaminants in the lower Athabasca River basin. Abstract only included

  8. 46th Street pilot street lighting project.

    Science.gov (United States)

    2013-01-01

    Street lighting improvements provide an opportunity for governments to save money and to reduce their : environmental footprint. New energy-efficient technologies are being perfected that are more efficient than : standard high-pressure sodium street...

  9. Uniqueness Deposit of Sediment on Floodplain Resulting From Lateral Accretion on Tropical Area : Study Case at Kampar River, Indonesia

    Directory of Open Access Journals (Sweden)

    Yuniarti Yuskar

    2017-03-01

    Full Text Available Kampar rivers has a length of 413 km with average depth of 7.7 m and width of 143 m. Sixty percent of  this rivers are meandering fluvial system which transport and deposit a mixture of suspended and bed-load (mixed load along low energy. River channel that moving sideways by erosion is undergoing lateral migration and the top of the point bar becomes the edge of the floodplain and the fining-upward succession of the point bar will be capped by overbank deposits of Kampar River. Along the Kampar Rivers, there are more than 60% of floodplain sediments and almost all of the floodplain formed by bend migration on the suspended-load channels of Kampar watershed. This formation consist of succession of fine to medium sand and silt/mud, with root traces, that form as drapes on the prograding bank. These beds dip mostly channel wards and quickly wedge out as they grade up and onto the floodplain. The depositional model is presented showing how lateral accretion can make a significant contribution to the preservation of fine-grained within channel deposits in contemporary floodplains. The examples presented here demonstrate that analogues to ancient point-bar deposits containing alternating sandstone and shale sequences are common in the low-energy fluvial environments of Riau rivers especially Kampar rivers.

  10. Dynamic transition of chemolithotrophic sulfur-oxidizing bacteria in response to amendment with nitrate in deposited marine sediments

    Directory of Open Access Journals (Sweden)

    Tomo eAoyagi

    2015-05-01

    Full Text Available Although environmental stimuli are known to affect the structure and function of microbial communities, their impact on the metabolic network of microorganisms has not been well investigated. Here, geochemical analyses, high-throughput sequencing of 16S rRNA genes and transcripts, and isolation of potentially relevant bacteria were carried out to elucidate the anaerobic respiration processes stimulated by nitrate (20 mM amendment of marine sediments. Marine sediments deposited by the Great East Japan Earthquake in 2011 were incubated anaerobically in the dark at 25°C for 5 days. Nitrate in slurry water decreased gradually for 2 days, then more rapidly until its complete depletion at day 5; production of N2O followed the same pattern. From day 2 to 5, the sulfate concentration increased and the sulfur content in solid-phase sediments significantly decreased. These results indicated that denitrification and sulfur oxidation occurred simultaneously. Illumina sequencing revealed the proliferation of known sulfur oxidizers, i.e., Sulfurimonas spp. and Chromatiales bacteria, which accounted for approximately 43.5% and 14.8% of the total population at day 5, respectively. They also expressed 16S rRNA to a considerable extent, whereas the other microorganisms, e.g., iron(III reducers and methanogens, became metabolically active at the end of the incubation. Extinction dilution culture in a basal-salts medium supplemented with sulfur compounds and nitrate successfully isolated the predominant sulfur oxidizers: Sulfurimonas sp. strain HDS01 and Thioalkalispira sp. strain HDS22. Their 16S rRNA genes showed 95.2−96.7% sequence similarity to the closest cultured relatives and they grew chemolithotrophically on nitrate and sulfur. Novel sulfur-oxidizing bacteria were thus directly involved in carbon fixation under nitrate-reducing conditions, activating anaerobic respiration processes and the reorganization of microbial communities in the deposited marine

  11. Do benthic sediment characteristics explain the distribution of juveniles of the deposit-feeding sea cucumber Australostichopus mollis?

    Science.gov (United States)

    Slater, Matthew J.; Jeffs, Andrew G.

    2010-10-01

    Despite the economic importance of many deposit-feeding sea cucumbers, the ecology of their juveniles is poorly understood and factors influencing juvenile habitat selection remain largely unexplained. We investigated the importance of the characteristics of the available sediment in determining the highly localised distribution of juveniles of the deposit-feeding Australasian sea cucumber Australostichopus mollis. Wild-caught juveniles were displaced to non-juvenile habitats with surface sediments characterised by lower total organic content (TOM) and nitrogen content, higher chlorophyll- a content and coarser grain size profiles compared to juvenile sites. The growth of displaced individual animals was monitored over 9 months and compared to control animals caged in the juvenile habitats. Displaced juvenile sea cucumbers had high survival rates that did not differ significantly from juvenile habitats. Displaced juveniles exhibited significantly higher specific growth rate (SGR) than those at juvenile sites ( p < 0.001), although the growth of individuals was highly variable within individual cages and among sites. The lower TOM and nitrogen content, and coarser grain size profiles at non-juvenile sites did not result in reductions in juvenile survival or growth. Higher microphytobenthic activity may have resulted in the higher growth rates observed at shallow non-juvenile sites. The SGR of juveniles over the first 6 months of the experiment ranged between 0.45% d - 1 and 0.74% d - 1 for all sites. This was followed by marked growth limitation between 6 and 9 months either as a result of increasing juvenile biomass in cages or seasonal growth limitation. A subsequent reduction in juvenile density resulted in markedly increased growth over the following 3 month period. Juvenile A. mollis show an ability to exploit a variety of benthic sediment food sources, indicating that their highly localised distribution is not due to differences in the food quality of

  12. Sediment depositional environment in some bays in Central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rajamanickam, G.V.; Gujar, A.R.

    negatively and Ratnagiri Bay positively skewed. Kalbadevi sediments show high kurtosis values while those of Mirya Bay show medium and Ratnagiri Bay low values. Bivariant plots between various textural parameters predict mixed environments, viz. for Kalbadevi...

  13. Depositional environment, organic matter characterization and hydrocarbon potential of Middle Miocene sediments from northeastern Bulgaria (Varna-Balchik Depression

    Directory of Open Access Journals (Sweden)

    Zdravkov Alexander

    2015-10-01

    Full Text Available The depositional environments and hydrocarbon potential of the siliciclastic, clayey and carbonate sediments from the Middle Miocene succession in the Varna-Balchik Depression, located in the south-eastern parts of the Moesian Platform, were studied using core and outcrop samples. Based on the lithology and resistivity log the succession is subdivided from base to top into five units. Siliciclastic sedimentation prevailed in the lower parts of units I and II, whereas their upper parts are dominated by carbonate rocks. Unit III is represented by laminated clays and biodetritic limestone. Units IV and V are represented by aragonitic sediments and biomicritic limestones, correlated with the Upper Miocene Topola and Karvuna Formations, respectively. Biogenic silica in the form of diatom frustules and sponge spicules correlates subunit IIa and unit III to the lower and upper parts of the Middle Miocene Euxinograd Formation. Both (subunits contain organic carbon contents in the order of 1 to 2 wt. % (median: 0.8 for subunit IIa; 1.3 for unit III, locally up to 4 wt. %. Based on Hydrogen Index values (HI and alkane distribution pattern, the kerogen is mainly type II in subunit IIa (average HI= 324 mg HC/g TOC and type III in unit III (average HI ~200 mg HC/g TOC. TOC and Rock Eval data show that subunit IIa holds a fair (to good hydrocarbon generative potential for oil, whereas the upper 5 m of unit III holds a good (to fair potential with the possibility to generate gas and minor oil. The rocks of both units are immature in the study area. Generally low sulphur contents are probably due to deposition in environments with reduced salinity. Normal marine conditions are suggested for unit III. Biomarker composition is typical for mixed marine and terrestrial organic matter and suggests deposition in dysoxic to anoxic environments.

  14. Uranium distribution and sandstone depositional environments: oligocene and upper Cretaceous sediments, Cheyenne basin, Colorado

    International Nuclear Information System (INIS)

    Nibbelink, K.A.; Ethridge, F.G.

    1984-01-01

    Wyoming-type roll-front uranium deposits occur in the Upper Cretaceous Laramie and Fox Hills sandstones in the Cheyenne basin of northeastern Colorado. The location, geometry, and trend of specific depositional environments of the Oligocene White River and the Upper Cretaceous Laramie and Fox Hills formations are important factors that control the distribution of uranium in these sandstones. The Fox Hills Sandstone consists of up to 450 ft (140 m) of nearshore marine wave-dominated delta and barrier island-tidal channel sandstones which overlie offshore deposits of the Pierre Shale and which are overlain by delta-plain and fluvial deposits of the Laramie Formation. Uranium, which probably originated from volcanic ash in the White River Formation, was transported by groundwater through the fluvial-channel deposits of the White River into the sandstones of the Laramie and Fox Hills formations where it was precipitated. Two favorable depositional settings for uranium mineralization in the Fox Hills Sandstone are: (1) the landward side of barrier-island deposits where barrier sandstones thin and interfinger with back-barrier organic mudstones, and (2) the intersection of barrier-island and tidal channel sandstones. In both settings, sandstones were probably reduced during early burial by diagenesis of contained and adjacent organic matter. The change in permeability trends between the depositional strike-oriented barrier sandstones and the dip-oriented tidal-channel sandstones provided sites for dispersed groundwater flow and, as demonstrated in similar settings in other depositional systems, sites for uranium mineralization

  15. Epigenetic-hydrothermal origin of the sediment-hosted Muellenbach uranium deposit, Baden-Baden, W-Germany

    International Nuclear Information System (INIS)

    Brockamp, O.; Zuther, M.; Clauer, N.

    1987-01-01

    Upper Carboniferous sediments on the margin of the northern Black Forest granite massif are the host rocks of the Muellenbach uranium deposit. According to K/Ar datings the sericites formed during the Jurassic (150 Ma), an age also interpreted from U/Pb ratios for the crystallization of the pitchblende. Based on vitrinite reflectance the mineralization temperature is estimated to be 240 0 -290 0 C. It is postulated that the hydrothermal solutions were supplied via deep-seated faults bordering and crosscutting the granite massif and the sedimentary trough which is an intramontane basin. In its immediate vicinity the rift valley of the Rhein graben developed. Uranium deposits in comparable settings are supposed to be predominately of epigenetic-hydrothermal origin. (orig./HP)

  16. Transport and deposition of asbestos-rich sediment in the Sumas River, Whatcom County, Washington

    Science.gov (United States)

    Curran, Christopher A.; Anderson, Scott W.; Barbash, Jack E.; Magirl, Christopher S.; Cox, Stephen E.; Norton, Katherine K.; Gendaszek, Andrew S.; Spanjer, Andrew R.; Foreman, James R.

    2016-02-08

    Heavy sediment loads in the Sumas River of Whatcom County, Washington, increase seasonal turbidity and cause locally acute sedimentation. Most sediment in the Sumas River is derived from a deep-seated landslide of serpentinite that is located on Sumas Mountain and drained by Swift Creek, a tributary to the Sumas River. This mafic sediment contains high amounts of naturally occurring asbestiform chrysotile. A known human-health hazard, asbestiform chrysotile comprises 0.25–37 percent, by mass, of the total suspended sediment sampled from the Sumas River as part of this study, which included part of water year 2011 and all of water years 2012 and 2013. The suspended-sediment load in the Sumas River at South Pass Road, 0.6 kilometers (km) downstream of the confluence with Swift Creek, was 22,000 tonnes (t) in water year 2012 and 49,000 t in water year 2013. The suspended‑sediment load at Telegraph Road, 18.8 km downstream of the Swift Creek confluence, was 22,000 t in water year 2012 and 27,000 t in water year 2013. Although hydrologic conditions during the study were wetter than normal overall, the 2-year flood peak was only modestly exceeded in water years 2011 and 2013; runoff‑driven geomorphic disturbance to the watershed, which might have involved mass wasting from the landslide, seemed unexceptional. In water year 2012, flood peaks were modest, and the annual streamflow was normal. The fact that suspended-sediment loads in water year 2012 were equivalent at sites 0.6 and 18.8 km downstream of the sediment source indicates that the conservation of suspended‑sediment load can occur under normal hydrologic conditions. The substantial decrease in suspended-sediment load in the downstream direction in water year 2013 was attributed to either sedimentation in the intervening river reach, transfer to bedload as an alternate mode of sediment transport, or both.The sediment in the Sumas River is distinct from sediment in most other river systems because of the

  17. Mercury isotope constraints on the source for sediment-hosted lead-zinc deposits in the Changdu area, southwestern China

    Science.gov (United States)

    Xu, Chunxia; Yin, Runsheng; Peng, Jiantang; Hurley, James P.; Lepak, Ryan F.; Gao, Jianfeng; Feng, Xinbin; Hu, Ruizhong; Bi, Xianwu

    2018-03-01

    The Lanuoma and Cuona sediment-hosted Pb-Zn deposits hosted by Upper Triassic limestone and sandstone, respectively, are located in the Changdu area, SW China. Mercury concentrations and Hg isotopic compositions from sulfide minerals and potential source rocks (e.g., the host sedimentary rocks and the metamorphic basement) were investigated to constrain metal sources and mineralization processes. In both deposits, sulfide minerals have higher mercury (Hg) concentrations (0.35 to 1185 ppm) than the metamorphic basement rocks (0.05 to 0.15 ppm) and sedimentary rocks (0.02 to 0.08 ppm). Large variations of mass-dependent fractionation (3.3‰ in δ202Hg) and mass-independent fractionation (0.3‰ in Δ199Hg) of Hg isotopes were observed. Sulfide minerals have Hg isotope signatures that are similar to the hydrothermal altered rocks around the deposit, and similar to the metamorphic basement, but different from barren sedimentary rocks. The variation of Δ199Hg suggests that Hg in sulfides was mainly derived from the underlying metamorphic basement. Mercury isotopes could be a geochemical tracer in understanding metal sources in hydrothermal ore deposits.

  18. Possible pitfalls in the search for uranium deposits using lake sediments and lake waters

    International Nuclear Information System (INIS)

    Levinson, A.A.; Bland, C.J.

    1978-01-01

    The organic-rich sediments from the centres of Canadian lakes are a valuable sampling medium in the search for uranium. However, because of the young age of hydromorphically transported uranium in these sediments, which must post-date the last period of glaciation, there has been insufficient time for the isotope 214 Bi to reach equilibrium with its ancestor 238 U. This results in equivalent uranium (eU) values significantly lower than actual uranium values determined by fluorometry or delayed neutron activation analysis. Radiometric ( 226 Ra) analyses of 12 centre-lake sediments from Seahorse Lake, Saskatchewan illustrate the potential pitfalls which may be encountered using gamma-ray spectrometry, as only 3-8% of the actual uranium present in most of the samples would have been detected. (author)

  19. Sediment budgets, transport, and depositional trends in a large tidal delta

    Science.gov (United States)

    Morgan, Tara; Wright, Scott A.

    2016-01-01

    The Sacramento-San Joaquin Delta is the largest delta on the west coast of the United States. It is formed where the confluence of California’s two largest rivers (the Sacramento and San Joaquin) meet the ocean tides and has a significant physical gradient from fluvial to tidal. It is a semidiurnal system (two high and two low tides per day). Today, the Delta is one of the most manipulated in the United States. Once composed of many shallow, meandering and braided dendritic channels and dead-end sloughs and wetlands, it is now a network of leveed canals moving clear water around subsided islands. It historically has supported a biologically diverse tidal wetland complex, of which only 3% remains today (Whipple et al., 2012). It has also witnessed a collapse in the native fish populations. The Delta provides critical habitat for native species, however the hydrology and water quality are complicated by manipulations and diversions to satisfy multiple statewide objectives. Today water managers face co-equal goals of water supply to Californians and maintenance of ecosystem health and function. The Delta is a hub for both a multi-hundred-million dollar agricultural industry and a massive north-to-south water delivery system, supplying the primary source of freshwater to Central Valley farmers and drinking water for two-thirds of California’s population. Large pump facilities support the water demand and draw water from the Delta, further altering circulation patterns and redirecting the net flow toward the export facilities (Monsen et al., 2007). Fluvial sedimentation, along with organic accumulation, creates and sustains the Delta landscape. Hydraulic mining for gold in the watershed during the late 1800s delivered an especially large sediment pulse to the Delta. More recently, from 1955 to the present, a significant sediment decline has been observed that is thought to have been caused mostly by the construction of water storage reservoirs that trap the upstream

  20. Geochronologic study of sediments deposition of two lakes from the Rio Negro basin, Amazonas State, Brazil

    International Nuclear Information System (INIS)

    Gomes, Ana Carla F.; Mozeto, Antonio A.; Cazotti, Raul I.; Nascimento Filho, Virgilio F.; Taddei, Maria Helena

    2000-01-01

    Since 1963 the radionuclide 210 Pb became an important tool for dating (geochronology) recent sediments (up to 120 years). In this work the sedimentary geochronology of two lakes from the Negro River Basin was determined, using different radiochemical separation methods for 210 Pb and 226 Ra. (author)

  1. Sediment deposition from forest roads at stream crossings as influenced by road characteristics

    Science.gov (United States)

    A.J. Lang; W.M. Aust; M.C. Bolding; K.J. McGuire

    2015-01-01

    Recent controversies associated with ditched forest roads and stream crossings in the Pacific Northwest have focused national attention on sediment production and best management practices (BMPs) at stream crossings. Few studies have quantified soil erosion rates at stream crossings as influenced by road characteristics and compared them to modeled rates. Soil erosion...

  2. Depositional characteristics and sediment availability resulting from the post-Schultz Fire floods of 2010

    Science.gov (United States)

    Karen A. Koestner; Mike D. Carroll; Daniel G. Neary; Peter E. Koestner; Ann Youberg

    2011-01-01

    Wildfire is a major land management concern due to direct impacts of fire on forest resources, and potentially negative effects on landscape processes by increasing rates of runoff, erosion, downstream sedimentation, and overall site degradation (DeBano et al. 1998, Neary et al. 2005, Robichaud et al. 2010). In the United States the number of fires has been increasing...

  3. Deposition of Mn-Cu-Ni-enriched sediments during glacial period in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Borole, D.V.

    Two siliceous sediment cores collected from the Central Indian Basin have been analysed for organic carbon, biogenic silica, Al, Mn, Ni and Cu content. The concentrations of Mn, Cu and Ni showed one order of magnitude variation (an enrichment by a...

  4. Sedimentation and paleoecology of Pliocene lagoonal-shallow marine deposits on the island of Rhodes (Greece)

    NARCIS (Netherlands)

    Broekman, J.A.

    1974-01-01

    A detailed analysis of the depositional and paleontological characteristics of a section of the Pliocene Kritika Formation on the island of Rhodos is presented. The environmental significance of sedimentary structures, the paleoecology of benthonic Foraminifera, and the sequentional

  5. Christmas Island lagoonal lakes, models for the deposition of carbonate–evaporite–organic laminated sediments

    OpenAIRE

    Trichet , Jean; Défarge , Christian; Tribble , J.; Tribble , G.W.; Sansone , F.J.

    2001-01-01

    The atoll of Christmas Island (now known as Kiritimati) in the Kiribati Republic (Central Pacific) lies at about 2°N in the intertropical convergence zone. Much of the surface area of the atoll (ca. 360 km2) is occupied by numerous lakes in which carbonate, evaporite (calcium sulfate, halite) and organic layers are deposited. Observations suggest that deposition of these different laminae is controlled by climatic and biologic factors. It is thought that periodic climatic variations, such as ...

  6. Spatial distributions and deposition chronology of short chain chlorinated paraffins in marine sediments across the Chinese Bohai and Yellow Seas.

    Science.gov (United States)

    Zeng, Lixi; Chen, Ru; Zhao, Zongshan; Wang, Thanh; Gao, Yan; Li, An; Wang, Yawei; Jiang, Guibin; Sun, Liguang

    2013-10-15

    As the most complex halogenated contaminants, short chain chlorinated paraffins (SCCPs) are scarcely reported in marine environments. In this work, a total of 117 surficial sediment (0-3 cm) samples and two sediment cores were collected from the Chinese Bohai and Yellow Seas to systematically study the spatial and temporal trends of SCCPs at a large scale in the Chinese marine environment. Total SCCP concentrations in the surficial sediments were in the range of 14.5-85.2 ng g(-1) (dry weight, d.w.) with an average level of 38.4 ng g(-1) d.w. Spatial distribution showed a decreasing trend with the distance from the coast to the open waters. Compositional pattern analysis suggested that C10 was the most predominant homologue group, followed by C11, C12, and C13 homologue groups. The concentrations of total SCCPs in sediment cores ranged from 11.6 to 94.7 ng g(-1) d.w. for YS1 and from 14.7 to 195.6 ng g(-1) d.w. for YS2, with sharp rise from the early 1950s to present based on (210)Pb dating technique. The historical records in cores correspond well to the production and usage changes of CPs in China. Multivariate regression statistics indicate TOC, latitude and longitude are the major factors influencing surficial SCCP levels in the Chinese East Seas by combining analysis with the data from the East China Sea (R(2) = 0.332, p < 0.01). These findings indicated that the sources of SCCPs were mainly from river outflows via ocean current and partly from atmospheric depositions by East Asian monsoon in the sampling areas.

  7. Effects of river morphology, hydraulic gradients, and sediment deposition on water exchange and oxygen dynamics in salmonid redds.

    Science.gov (United States)

    Schindler Wildhaber, Y; Michel, C; Epting, J; Wildhaber, R A; Huber, E; Huggenberger, P; Burkhardt-Holm, P; Alewell, C

    2014-02-01

    Fine sediment decreasing gravel permeability and oxygen supply to incubating salmonid embryos, is often considered the main contributing factor for the observed decline of salmonid populations. However, oxygen supply to salmonid embryos also depends on hydraulic conditions driving water flow through the redd. A more generalized perspective is needed to better understand the constraints on successful salmonid incubation in the many heavily modified fluvial ecosystems of the Northern Hemisphere. The effects of hydraulic gradients, riverbed and redd morphology as well as fine sediment deposition on dissolved oxygen (DO) and water exchange was studied in 18 artificial redds at three sites along a modified river. Fifty percent of the redds in the two downstream sites were lost during high flow events, while redd loss at the upstream site was substantially lower (8%). This pattern was likely related to increasing flood heights from up- to downstream. Specific water infiltration rates (q) and DO were highly dynamic and driven on multiple temporal and spatial scales. Temporally, the high permeability of the redd gravel and the typical pit-tail structure of the new built redds, leading to high DO, disappeared within a month, when fine sediment had infiltrated and the redd structure was leveled. On the scale of hours to days, DO concentrations and q increased during high flows, but decreased during the falling limb of the water level, most likely related to exfiltration of oxygen depleted groundwater or hyporheic water. DO concentrations also decreased under prolonged base flow conditions, when increased infiltration of silt and clay particles clogged the riverbed and reduced q. Spatially, artificial log steps affected fine sediment infiltration, q and interstitial DO in the redds. The results demonstrate that multiple factors have to be considered for successful river management in salmonid streams, including riverbed structure and local and regional hydrogeological

  8. Bacterial profiling of Saharan dust deposition in the Atlantic Ocean using sediment trap moorings – year one results

    Science.gov (United States)

    Munday, Chris; Brummer, Geert-Jan; van der Does, Michelle; Korte, Laura; Stuut, Jan-Berend

    2015-04-01

    Large quantities of dust are transported from the Sahara Desert across the Atlantic Ocean towards the Caribbean each year, with a large portion of it deposited in the ocean. This dust brings an array of minerals, nutrients and organic matter, both living and dead. This input potentially fertilizes phytoplankton growth, with resulting knock-on effects throughout the food chain. The input of terrestrial microbial life may also have an impact on the marine microbial community. The current multi-year project consists of a transect of floating dust collectors and sub-surface sediment traps placed at 12°N across the Atlantic Ocean. Sediment traps are located 1200m and 3500m below the sea surface and all are synchronized to collect samples for a period of two weeks. The aim is to understand the links between dust input and the bacterial community and how this relates to ocean productivity and the carbon cycle. The first set of sediment trap samples were recovered using the RV Pelagia in November 2013 with promising results. Results from 7 sediment traps (three at 1200m and four at 3500m) were obtained. In general, the total mass flux decreased as distance from the source increased and the upper traps generally held more material than those at 3500m. Denaturing Gradient Gel Electrophoresis (DGGE) was used as a screening technique, revealing highly varied profiles, with the upper (1200m) traps generally showing more variation throughout the year. Several samples have been submitted for high throughput DNA sequencing which will identify the variations in these samples.

  9. The applicability of the sediment deposition geochronology with 2'1'0PB as a tool in the sediment accumulation from the Taquari River, Pantanal, MS, Central region, Brazil

    International Nuclear Information System (INIS)

    Godoy, J.M.; Padovani, C.R.; Vieira, L.M.; Pereira, J.C.A.

    1998-01-01

    This work presents 210 Pb geochronology of five bottom sediment cores from flood plain lakes of middle Taquari River, Pantanal, MS. In two cores of a same lake, an increase of the sediment deposition rate were observed, reflecting an increasing of the sediment input to the Pantanal. The main causes suggested for this increasing are climatic change, and the development of agriculture and cattle-raising in the watershed highlands, for the last 25 years. The results pointed too for the importance of a additional sample in the superior region of the middle Taquari River. (author)

  10. The Effect of Sedimentation Conditions of Frozen Deposits at the Kolyma Lowland on the Distribution of Methane and Microorganisms Activity

    Science.gov (United States)

    Oshurkova, V.; Kholodov, A. L.; Spektor, V.; Sherbakova, V.; Rivkina, E.

    2014-12-01

    Biogeochemical and microbiological investigations of methane distribution and origin in Northeastern Arctic permafrost sediments indicated that microbial methane production was observed in situ in thawed and permanently frozen deposits (Rivkina et al., 2007). To check the hypothesis about the correlation between permafrost ground type and quantity of methane, produced by microorganisms, the samples from deposits of thermokarst depression (alas), Yedoma and fluvial deposits of Kolyma floodplain for gas measurements and microbiological study were collected and the experiment with anaerobic incubation was conducted. Gas analysis indicated that alas and floodplain samples were characterized by high methane concentrations whereas Yedoma samples had only traces of methane. Two media with different substrates were prepared anaerobically for incubation. First medium contained sucrose as a substrate for hydrolytic microflora and the second one contained acetate as a substrate for methanogens. Two samples from alas, one sample from Yedoma and one from floodplain were placed in anaerobic bottles and media under gas mixture (N2, CO2 and H2) were added. The bottles were incubated for 2 weeks at room temperature. The results of the experiment showed that there was the increase of methane concentrations in the bottles with Yedoma and Floodplain samples to 52-60 and 67-90 %, respectively, from initial concentrations in contrast with Alas sample inoculated bottles. At the same time the concentration of methane in control bottles, which did not include substrates, increased to 15-19%. Current research is a part of NSF funded project "The Polaris".

  11. Palynostratigraphy, palynofacies and palaeoenvironment of deposition of Selandian to Aquitanian sediments, southeastern Nigeria

    Science.gov (United States)

    Okeke, Kingsley K.; Umeji, Obianuju P.

    2016-08-01

    Investigation of outcrop sections along the Onitsha-Awka transect in the Niger Delta Basin southeastern Nigeria was undertaken to assess the palynological composition, palynofacies and palaeoenvironment of deposition. Stratigraphic ranges of palynomorphs suggest an age of Selandian to Aquitanian. The palynological composition is marked by abundance of dinoflagellate cysts in the Imo Formation (Selandian to Thanetian), dominance of spores and pollen over dinoflagellate cysts in the Nanka Formation (Ypresian to Bartonian), and overwhelming amounts of spore and pollen in the Ogwashi Formation (Pariabonian to Aquitanian). Palynofacies content shows dominance of structureless organic matter in the Imo Formation, few phytoclasts in the Nanka Formation and maximum phytoclast amounts in the Ogwashi Formation. Thanetian to Ypresian boundary was marked by the mixing of older Palaeocene and younger Eocene microfossils, decrease of microflora towards the end of Palaeocene and the evolution of abundant and more diverse Eocene taxa. The Imo Formation was deposited in middle to outer neritic zone based on abundance of gonyaulacacean cysts. However, peridiniacean and terrestrial microflora extend the deposition range to shallow waters of inner neritic and coastal zone. Increase in diversity and abundance of terrestrial palynomorphs over marine palynomorphs assemblages in the overlying Nanka Formation suggest deposition under alternating coastal and inner neritic conditions while the Ogwashi Formation records oscillating coastal plain and brackish water depositional conditions. The palaeoenvironments illustrate that general retrogradation was followed by progradation of the delta during the Cenozoic.

  12. Influence of variable rates of neritic carbonate deposition on atmospheric carbon dioxide and pelagic sediments

    Science.gov (United States)

    Walker, J. C.; Opdyke, B. C.

    1995-01-01

    Short-term imbalances in the global cycle of shallow water calcium carbonate deposition and dissolution may be responsible for much of the observed Pleistocene change in atmospheric carbon dioxide content. However, any proposed changes in the alkalinity balance of the ocean must be reconciled with the sedimentary record of deep-sea carbonates. The possible magnitude of the effect of shallow water carbonate deposition on the dissolution of pelagic carbonate can be tested using numerical simulations of the global carbon cycle. Boundary conditions can be defined by using extant shallow water carbonate accumulation data and pelagic carbonate deposition/dissolution data. On timescales of thousands of years carbonate deposition versus dissolution is rarely out of equilibrium by more than 1.5 x 10(13) mole yr-1. Results indicate that the carbonate chemistry of the ocean is rarely at equilibrium on timescales less than 10 ka. This disequilibrium is probably due to sea level-induced changes in shallow water calcium carbonate deposition/dissolution, an interpretation that does not conflict with pelagic sedimentary data from the central Pacific.

  13. Technical Guidelines on Performing a Sediment Erosion and Deposition Assessment (SEDA) at Superfund Sites

    Science.gov (United States)

    2014-09-01

    introduced to a water body because of the failure of a river bank due to, for example, flow-induced erosion of the bank toe and/or surface, or...under supercritical flows (with Froude number greater than one). Antidunes are usually more symmetrical (in their longitudinal profile) than dunes ... dunes , and anti- dunes . Bedload Sediment material moving on top of or near a channel bed by rolling, sliding, and saltating, i.e., jumping

  14. Mapping sediment deposite on tank FB-901 using neutron back scattering technique

    International Nuclear Information System (INIS)

    Wibisono; Sugiharto; Zulkifli Lubis; Phyu Phyu Aung Myint; Thin Moe Hlaing

    2016-01-01

    Tank FB-901 is storage tank for temporary material production with a diameter 11 m and a high 12 m. This tank has been use about 10 years so it is suspected there is sediment in it. Neutron back scattering technique has been used to detected the level of sediment inside so it can be seen the volume of liquid properly and avoid problem in the nozzle outlet. AmBe neutron source with activity one Curie shoot into the tank to enable back scattering intensity from material. Measurement using He-3 detector, radiation counter Ludlum model 2200 scaler ratemeter and mechanical motor controlled by computer. Investigation were taken at around the tank from the bottom to the top on each step 50 mm height 8000 mm. Scan determined the distance between 500 mm and measurement time 3 seconds to each sample point. Investigation found the sediment level average 1000 mm by 1500 mm highest and lowest level 100 mm. Fluctuating liquid level observed maximum of 7800 mm and average of 7000 mm. Cleaning tank advised to avoid blockage of the nozzle and material volume is measured accurately. (author)

  15. Deposition behavior, risk assessment and source identification of heavy metals in reservoir sediments of Northeast China.

    Science.gov (United States)

    Zhu, Lin; Liu, Jianwei; Xu, Shiguo; Xie, Zaigang

    2017-08-01

    Sediment cores from five reservoirs, located in the Liaoning and Jilin Provinces in Northeast China, were collected to investigate the accumulation and potential toxicity of heavy metals (Fe, Mn, Cu, Cd, Pb, Zn, and Cr) during a sampling campaign in February, 2015. The results showed that all the detected metals accumulated significantly, especially Cd, compared to their respective background values. Among these reservoirs, Biliuhe Reservoir had markedly increasing trends for organic matter and all the metals, among which Mn was elevated by 280% to 3411mg/kg in a core of only 18cm in depth. Xinlicheng Reservoir was characterized by heavy siltation and varying metal distribution due to its regular geometric features and pulsed flood events. The Enrichment factor (EF) and geo-accumulation index (I geo ) indicated Cd was strongly enriched by anthropogenic inputs, with the values of EF and I geo greater than 8 and 3, respectively. The toxicity assessment calculated using consensus-based sediment quality guidelines (SQGs) implied the whole cores of Tanghe and Dahuofang and the upper cores of Biliuhe, Xinlicheng and Fengman exhibited toxicity to sediment-dwelling organisms. Cr contributed more to Q m-PEC than the other heavy metals, because only Cr exceeded the probable effect concentration (PEC) despite its low enrichment. According to the results of correlation analysis (CA) and principal components analysis (PCA), mining industries and agricultural activities within the basin were the main anthropogenic pollution sources for these heavy metals. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Depositional dynamics in the El'gygytgyn Crater margin: implications for the 3.6 Ma old sediment archive

    Directory of Open Access Journals (Sweden)

    G. Schwamborn

    2012-11-01

    Full Text Available The combination of permafrost history and dynamics, lake level changes and the tectonical framework is considered to play a crucial role for sediment delivery to El'gygytgyn Crater Lake, NE Russian Arctic. The purpose of this study is to propose a depositional framework based on analyses of the core strata from the lake margin and historical reconstructions from various studies at the site. A sedimentological program has been conducted using frozen core samples from the 141.5 m long El'gygytgyn 5011-3 permafrost well. The drill site is located in sedimentary permafrost west of the lake that partly fills the El'gygytgyn Crater. The total core sequence is interpreted as strata building up a progradational alluvial fan delta. Four macroscopically distinct sedimentary units are identified. Unit 1 (141.5–117.0 m is comprised of ice-cemented, matrix-supported sandy gravel and intercalated sandy layers. Sandy layers represent sediments which rained out as particles in the deeper part of the water column under highly energetic conditions. Unit 2 (117.0–24.25 m is dominated by ice-cemented, matrix-supported sandy gravel with individual gravel layers. Most of the Unit 2 diamicton is understood to result from alluvial wash and subsequent gravitational sliding of coarse-grained (sandy gravel material on the basin slope. Unit 3 (24.25–8.5 m has ice-cemented, matrix-supported sandy gravel that is interrupted by sand beds. These sandy beds are associated with flooding events and represent near-shore sandy shoals. Unit 4 (8.5–0.0 m is ice-cemented, matrix-supported sandy gravel with varying ice content, mostly higher than below. It consists of slope material and creek fill deposits. The uppermost metre is the active layer (i.e. the top layer of soil with seasonal freeze and thaw into which modern soil organic matter has been incorporated. The nature of the progradational sediment transport taking place from the western and northern crater margins may be

  17. Descriptive models, grade-tonnage relations, and databases for the assessment of sediment-hosted copper deposits: with emphasis on deposits in the Central Africa Copperbelt, Democratic Republic of the Congo and Zambia: Chapter J in Global mineral resource assessment

    Science.gov (United States)

    Taylor, Cliff D.; Causey, J. Douglas; Denning, Paul; Hammarstrom, Jane M.; Hayes, Timothy S.; Horton, John D.; Kirschbaum, Michael J.; Parks, Heather L.; Wilson, Anna B.; Wintzer, Niki E.; Zientek, Michael L.

    2013-01-01

    The Central African Copperbelt (CACB) is one of the most important copper-producing regions of the world. The majority of copper produced in Africa comes from this region defined by the Neoproterozoic Katanga sedimentary basin of the southern Democratic Republic of the Congo (DRC) and northern Zambia. Copper in the CACB is mined from sediment-hosted stratabound copper deposits associated with red beds and includes the giant deposits in the Kolwezi and Tenge-Fungurume districts in the DRC and the Konkola-Musoshi and Nchanga-Chingola districts in Zambia. In recent years, sediment-hosted structurally controlled replacement and vein (SCRV) copper deposits, such as the giant Kansanshi deposit in Zambia have become important exploration targets in the CACB region.

  18. Determining the Role of Sediment Deposition and Transport in the Formation and Maintenance of Tree Islands in the Florida Everglades

    Science.gov (United States)

    Mitchell-Bruker, S.; Childers, D.; Ross, M.; Leonard, L.; Solo-Gabriel, H.; Stothoff, S.

    2002-05-01

    Tree islands are a prominent feature in the Everglades ridge and slough wetlands. These tree islands are believed to be a remnant of the historical pre-drainage flow system. Within Everglades National Park, hardwood hammock and bayhead tree islands commonly form as teardrop-shaped mounds, rising above the sawgrass marsh. These tree islands are usually oriented along the direction of surface water flow, with the highest elevation and widest part of the island at the upstream head. The island narrows as it descends into the marsh at the downstream end, terminating in a tail that sometimes includes a zone of dead or dying sawgrass. The shape and orientation of the tree islands suggests that surface water flow has been instrumental in their formation, however occasional flow measurements indicate that the slow moving water of the Everglades does not provide sufficient energy to transport even moderate amounts of suspended sediment. This low flow velocity, coupled with the extremely low turbidity of the Everglades water suggests that if sediment transport and deposition processes are instrumental in forming tree islands, the process is probably occurring over short distances and long time intervals. It is also possible that concentration and transport of nutrients is an important element in tree island formation. Because the Everglades marsh is a low nutrient environment, processes that create areas of increased phosphorous concentration result in changes in the vegetation. Because many hardwood hammock and bayhead tree islands have heads that are situated on bedrock highs, the higher and drier elevation of the head allows for trees to grow. These trees could concentrate phosphorous either by acting as wildlife attractors, or by acting as \\x8Dphosphorous pumpsŒ, transporting groundwater with high concentrations of phosphorous through the roots to the tree. We are characterizing vegetation, litter fall, sediments, surface water flow, hydrologic gradients and nutrient

  19. Observations on the relation between lacustrine facies and uranium deposits in continental sediments

    International Nuclear Information System (INIS)

    Noble, E.A.

    1981-01-01

    A recent sedimentological concept and approach in the evaluation of lacustrine deposition environments for their geological uranium potential are described. The presence of certain types of limonite seems to be a key factor in the process of leaching, the formation of pyrite and the precipitation of uranium. (author)

  20. Allegheny County Street Centerlines

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset contains the locations of the street centerlines for vehicular and foot traffic in Allegheny County. Street Centerlines are classified as Primary Road,...

  1. Geophysical imaging of the lacustrine sediments deposited in the La Calderilla Volcanic Caldera (Gran Canaria Island, Spain) for paleoclimate research

    Science.gov (United States)

    Himi, Mahjoub; Rodríguez-González, Alejandro; Criado, Constantino; Tapias, Josefina C.; Ravazzi, Cesare; Pérez-Torrado, Francisco; Casas, Albert

    2016-04-01

    The discovery of well-preserved maar structures is important not only for studying the eruptive activity and formation of volcanoes, but also for paleoclimate research, since laminated maar lake sediments may contain very detailed archives of climate and environmental history. Maars are a singular type of volcanic structure generated by explosive phreatomagmatic eruptions as a result of interaction between rising magma and groundwater. This kind of structures are characterised by circular craters, often filled with water and/or lacustrine sediments and surrounded by a ring of pyroclastic deposits.Recently a borehole was drilled at the bottom of La Calderilla volcanic complex which penetrated about 8.7 m in its sedimentary sequence and paleobotanical study has supplied the first evidence of paleoenvironmental evolution during the Holocene on the Gran Canaria Island. This survey, however, did not penetrate into the substrate because the total thickness of the sedimentary fill was unknown. Since the age of formation of La Calderilla volcanic complex based on K/Ar dating is about 85,000 years (Upper Pleistocene), the possibility of its sedimentary fill extends beyond of the Holocene is extremely attractive, since, for example, there are few paleoenvironmental data regarding how much the last glaciation that affected the Canary Islands. In these circumstances, the knowledge of the total thickness of the lacustrine sediments is crucial to design a deeper borehole in the next future. Therefore, the subsurface characterisation provided by geophysics is essential for determining thickness and geometry of the sedimentary filling. Multielectrode ERT method was used to obtain five 2-D resistivity cross-sections into La Calderilla volcanic caldera. An Iris Syscal Pro resistivity system with 48 electrodes connected to a 94 m long cable (2m electrode spacing) in Wenner-Schlumberger configuration for an investigation depth of about 20 m. Data quality (q Current injected was

  2. Morava River flood plain sediments deposited during the last millennium: Climatic and anthropogenic record

    Czech Academy of Sciences Publication Activity Database

    Kadlec, Jaroslav; Grygar, Tomáš; Světlík, Ivo; Ettler, V.; Mihaljevič, M.; Diehl, J.; Beske-Diehl, S.

    2008-01-01

    Roč. 34, 4/6 (2008), s. 1338314-1338314 ISSN 0161-6951. [International Geological Congress /33./. 06.08.2008-14.08.2008, Oslo ] R&D Projects: GA AV ČR IAA300130505; GA AV ČR IAA3013201; GA AV ČR IAAX00130801 Institutional research plan: CEZ:AV0Z30130516; CEZ:AV0Z40320502; CEZ:AV0Z10480505 Keywords : Morava River * flood * plain sediments * magnetic minerals Subject RIV: DB - Geology ; Mineralogy

  3. Towards an event stratigraphy for Baltic Sea sediments deposited since AD 1900

    DEFF Research Database (Denmark)

    Moros, Matthias; Andersen, Thorbjørn Joest; Schulz-Bull, Detlef

    2017-01-01

    of anthropogenic radionuclides (137Cs/241Am/bomb14C), polychlorinated biphenyls (PCBs), lead (Pb) and stable lead isotope (206/207Pb ratios), and radionuclide 210Pb and 14C decay dating methods. Marker horizons consisting of chemical precipitates formed by documented Major Baltic Inflow (MBIs) events...... and an extended diatom bloom period were also integrated into the model. The main time markers in Baltic Sea sediments that formed during the last 120 years were the following: (i) the deepest observation of 210Pbunsupp. (marking the 210Pb dating horizon) and departure of Hg from natural background levels at c...

  4. Effects of sediment-associated copper to the deposit-feeding snail, Potamopyrgus antipodarum

    DEFF Research Database (Denmark)

    Pang, Chengfang; Selck, Henriette; Misra, Superb K

    2012-01-01

    the case of metal oxide NPs using CuO to understand if the effects of NPs differ from micron-sized particles of CuO and aqueous Cu (CuCl2). To address this issue, we compared effects of copper added to the sediment as aqueous Cu, nano- (6 nm) and micro- (... greater effects on growth, feeding rate, and reproduction of P. antipodarum than copper added as micro-CuO or aqueous Cu. P. antipodarum accumulated more copper in the nano-CuO treatment than in aqueous Cu or micro-CuO treatments, indicating that consideration of metal form may be important when assessing...

  5. Numerical experiment on tsunami deposit distribution process by using tsunami sediment transport model in historical tsunami event of megathrust Nankai trough earthquake

    Science.gov (United States)

    Imai, K.; Sugawara, D.; Takahashi, T.

    2017-12-01

    A large flow caused by tsunami transports sediments from beach and forms tsunami deposits in land and coastal lakes. A tsunami deposit has been found in their undisturbed on coastal lakes especially. Okamura & Matsuoka (2012) found some tsunami deposits in the field survey of coastal lakes facing to the Nankai trough, and tsunami deposits due to the past eight Nankai Trough megathrust earthquakes they identified. The environment in coastal lakes is stably calm and suitable for tsunami deposits preservation compared to other topographical conditions such as plains. Therefore, there is a possibility that the recurrence interval of megathrust earthquakes and tsunamis will be discussed with high resolution. In addition, it has been pointed out that small events that cannot be detected in plains could be separated finely (Sawai, 2012). Various aspects of past tsunami is expected to be elucidated, in consideration of topographical conditions of coastal lakes by using the relationship between the erosion-and-sedimentation process of the lake bottom and the external force of tsunami. In this research, numerical examination based on tsunami sediment transport model (Takahashi et al., 1999) was carried out on the site Ryujin-ike pond of Ohita, Japan where tsunami deposit was identified, and deposit migration analysis was conducted on the tsunami deposit distribution process of historical Nankai Trough earthquakes. Furthermore, examination of tsunami source conditions is possibly investigated by comparison studies of the observed data and the computation of tsunami deposit distribution. It is difficult to clarify details of tsunami source from indistinct information of paleogeographical conditions. However, this result shows that it can be used as a constraint condition of the tsunami source scale by combining tsunami deposit distribution in lakes with computation data.

  6. The history and source of particulate 137Cs and 239,240Pu deposition in sediments of the Ob River Delta, Siberia

    International Nuclear Information System (INIS)

    Sayles, F.L.; Livingston, H.D.; Panteleyev, G.P.

    1997-01-01

    This paper presents the first results of a project designed to examine the transfer of particle-associated artificial radionuclides down the Ob River in Siberia to its delta over the past 5 decades. The main sources include fallout from atmospheric nuclear weapons tests and weapons complexes and test sites of the Former Soviet Union in or near the Ob watershed. The approach is to measure the accumulation of the radionuclides in undisturbed delta sediments - obtaining a record of their deposition over time. These records were found in sediments of shallow lakes apart from, and connected to, the main channel. Sediment cores were collected in the summer of 1994 using a shallow draft catamaran to reach these lakes from a support ship in the main channel. Measurements are presented on the depth distributions of 137 Cs and Pu isotopes and their inventories in a series of dated sediment cores - including one from a location in the Taz Estuary (which does not receive Ob River sediments). Sediment dating was carried out using the excess 210 Pb technique. The results obtained are compared with known information on the temporal history of releases from the various sources and characteristics of the isotopic composition of the sources. The results show that good records of radionuclide deposition indicate that the major fraction of 137 Cs and Pu isotopes deposited in these delta sediments comes from atmospheric nuclear weapons test fallout - both delivered directly from the atmosphere and from downstream transport of watershed sediments. No more than 25% of the observed inventories could be derived from other sources

  7. Geochemical and geological constraints on the composition of marine sediment pore fluid: Possible link to gas hydrate deposits

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumdar, A.; Joao, H.M.; Peketi, A.; Dewangan, P.; Kocherla, M.; Joshi, R.K.; Ramprasad, T.

    Pore water sulfate consumption in marine sediments is controlled by microbially driven sulfate reduction via organo-clastic and methane oxidation processes. In this work, we present sediment pore fluid compositions of 10 long sediment cores and high...

  8. Araçatuba Formation: palustrine deposits from the initial sedimentation phase of the Bauru Basin

    Directory of Open Access Journals (Sweden)

    Fernandes Luiz A.

    2003-01-01

    Full Text Available The Bauru Basin (Upper Cretaceous accumulated an essentially sandy continental sedimentary sequence. In a first desertic phase the basaltic substratum was covered by a widespread and homogeneous aeolian sand unit with minor loess intercalations. The substratum relief favored the formation of an endorheic drainage system under semi-arid climate, a process that started the development of the Araçatuba Paleoswamp. The palustrine deposits (Araçatuba Formation comprise siltstone and tipically greenish gray narrow tabular strata of sandstone cemented by carbonate. Moulds and gypsite and dolomite pseudomorphs were identified. The moulds seem to be genetically associated with desiccation cracks, root marks and climbing ripple lamination levels, that, on the whole, indicate calm shallow saline waters undergoing phases of subaerial exposition. At the boundaries of the study area, sand units may exhibit sigmoidal features and convolute bedding structure, which is characteristic of marginal deltaic deposits. The Araçatuba Formation is enclosed in and later overlaid by the aeolian deposits of the Vale do Rio do Peixe Formation.

  9. Sediment transport modeling in deposited bed sewers: unified form of May's equations using the particle swarm optimization algorithm.

    Science.gov (United States)

    Safari, Mir Jafar Sadegh; Shirzad, Akbar; Mohammadi, Mirali

    2017-08-01

    May proposed two dimensionless parameters of transport (η) and mobility (F s ) for self-cleansing design of sewers with deposited bed condition. The relationships between those two parameters were introduced in conditional form for specific ranges of F s , which makes it difficult to use as a practical tool for sewer design. In this study, using the same experimental data used by May and employing the particle swarm optimization algorithm, a unified equation is recommended based on η and F s . The developed model is compared with original May relationships as well as corresponding models available in the literature. A large amount of data taken from the literature is used for the models' evaluation. The results demonstrate that the developed model in this study is superior to May and other existing models in the literature. Due to the fact that in May's dimensionless parameters more effective variables in the sediment transport process in sewers with deposited bed condition are considered, it is concluded that the revised May equation proposed in this study is a reliable model for sewer design.

  10. The Eocene Rusayl Formation, Oman, carbonaceous rocks in calcareous shelf sediments: Environment of deposition, alteration and hydrocarbon potential

    Energy Technology Data Exchange (ETDEWEB)

    Dill, H.G.; Wehner, H.; Kus, J. [Federal Institute for Geosciences and Natural Resources, P.O. Box 510163, D-30631 Hannover (Germany); Botz, R. [University Kiel, Geological-Paleontological Department, Olshausenstrasse 40-60, D-24118 Kiel (Germany); Berner, Z.; Stueben, D. [Technical University Karlsruhe, Institute for Mineralogy and Geochemistry, Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Al-Sayigh, A. [Sultan Qaboos University, Geological Dept. PO Box 36, Al-Khod (Oman)

    2007-10-01

    Paralic carbonaceous series intercalated among calcareous shelf sediments have seldom been investigated. During the early Eocene, calcareous and siliciclastic sediments were deposited on a wide shelf in front of low-reliefed hinterland in the Al Khawd region in NE Oman. The siliciclastic-calcareous sediments originated from strongly reworked debris of the Arabic Shield. The underlying Semail Ophiolite did not act as a direct source of debris but provided some heat to increase the maturity of carbonaceous rocks and modify the isotope signal of the calcareous minerals in the Rusayl Formation. A multidisciplinary approach involving sedimentology, mineralogy, chemistry, coal petrography and paleontology resulted in the establishment of nine stratigraphic lithofacies units and provides the reader with a full picture from deposition of the mixed carbonaceous-calcareous-siliciclastic rocks to the most recent stages of post-depositional alteration of the Paleogene formations. The calcareous Jafnayn Formation (lithofacies unit I) developed in a subtidal to intertidal regime, influenced episodically by storms. Deepening of the calcareous shelf towards younger series was ground to a halt by paleosols developing on a disconformity (lithofacies unit II) and heralding the onset of the Rusayl Formation. The stratigraphic lithofacies units III and IV reflect mangrove swamps which from time to time were flooded through washover fans from the open sea. The presence of Spinozonocolpites and the taxon Avicennia, which today belong to a coastal marsh vegetational community, furnish palynological evidence to the idea of extensive mangrove swamps in the Rusayl Formation [El Beialy, S.Y., 1998. Stratigraphic and palaeonenvironmental significance of Eocene palynomorphs from the Rusayl Shale Formation, Al Khawd, northern Oman. Review of Palaeobotany and Palynology 102, 249-258]. During the upper Rusayl Formation (lithofacies units V through VII) algal mats episodically flooded by marine

  11. Bioaccumulation and effect of sediment-associated silver in different forms in two marine deposit feeders

    DEFF Research Database (Denmark)

    Dai, Lina; Banta, Gary Thomas; Syberg, Kristian

    2014-01-01

    Due to wide spread applications of nanoparticles, including Ag, in our daily life, these novel particles are receiving increasing attention by risk assessors. Many studies have been performed to test the toxicity of nanoparticles at the subcellular level. Despite these findings, there is still...... limited information at the whole organism level as to whether metallo-nanoparticles differ in toxicity from the same metals added to the environment in ionic or bulk form. In the present study, two organisms (i.e., a marine polychaete, Capitella teleta and a marine bivalve, Macoma balthica) were exposed...... to sediment amended with Ag in various forms (ionic Ag(I), nano-sized Ag and micron-sized Ag), and toxic endpoints were assessed at the whole organism level. After exposure for several weeks, no significant toxic effects were detected (i.e., mortality, growth rate and condition index) at the whole organism...

  12. 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

  13. Geologic characteristics of sediment- and volcanic-hosted disseminated gold deposits - Search for an occurrence model

    Science.gov (United States)

    White, Donald E.; Fournier, Robert O.; Rytuba, James J.; Rye, Robert O.; Cunningham, Charles G.; Berger, Byron R.; Silberman, Miles L.; Bonham, Harold F.; Strachan, Donald G.; Birak, Donald J.; Hawkins, Robert J.; Tooker, Edwin W.; Tooker, Edwin W.

    1985-01-01

    The current expansion of resource information, particularly on "disseminated" gold, and the improved technologies now available for resource investigations should place us in an enhanced position for developing a better predictive methodology for meeting one of the important responsibilities of the U.S. Geological Survey-to examine and assess the mineral resources of the geologic terranes composing the public (and privately owned) lands of the United States. The first step is systematic organization of these data. Geologic-occurrence models are an effective systematic method by which to organize large amounts of resource information into a logical sequence facilitating its use more effectively in meeting several industry and Survey objectives, which include the exploration for resources and the assessment of resource potential for land-use decisions. Such models also provide a scientific basis for metallogenesis research, which considers the observable features or attributes of ore occurrence and their "fit" into the Earth's resource puzzle. The use of models in making resource assessments/appraisals was addressed by Shawe (1981), who reported the results of a workshop on methods for resource appraisal of Wilderness and Conterminous United States Mineral Appraisal Program (CUSMAP; 1:250,000-scale quadrangles) areas. The Survey's main objective in the 1982 workshop was to evaluate the status of knowledge about disseminated or very fine grained gold deposits and, if possible, to develop an occurrence model(s).This report on the workshop proceedings has three main objectives: (1) Education through the publication of a summary review and presentation of new thinking and observations about the scientific bases for those geologic processes and environments that foster disseminated gold-ore formation; (2) systematic organization of available geologic, geochemical, and geophysical information for a range of typical disseminated gold deposits (including recognition of gaps

  14. 210Pb dating of sediments from the central and the northern Adriatic Sea: The deposition and preservation of sedimentary organic carbon

    International Nuclear Information System (INIS)

    Hamilton, T.; Fowler, S.; Miquel, J.C.; La Rosa, J.

    1996-04-01

    A central goal of the ELNA project is to assess the carbon assimilation capacity of the Northern Adriatic Sea. This requires fundamental quantitative information on budgets and sinks of organic carbon. Any change in carbon production in the water column should be reflected in the underlying sediments. Moreover, the fraction of particulate organic carbon reaching the sea floor which is subsequently preserved in the sediment will be strongly coupled to sediment accumulation and mixing. In this study a series of box cores were collected in order to characterize a hypothetical eutrophication gradient extending from the Po River outflow region in the north down to the shallow meso-Adriatic depression (Jabuka Pit). The main tasks assigned to IAEA-MEL were to provide 210 Pb derived sedimentation and dry-mass accumulation rates and to examine the possible correlations between sedimentary processes, the deposition and preservation of sedimentary organic carbon and pelagic primary productivity

  15. Microbial methane in the shallow Paleozoic sediments and glacial deposits of Illinois, U.S.A.

    Science.gov (United States)

    Coleman, D.D.; Liu, Chao-Li; Riley, K.M.

    1988-01-01

    Methane formed by the microbial decomposition of buried organic matter is virtually ubiquitous in the groundwaters of Illinois. Chemical and carbon isotopic compositions are reported for gas samples collected from over 200 private and municipal water wells and from 39 small gas wells completed in glacial deposits (drift-gas wells). Carbon and hydrogen isotopic data for methane, carbon dioxide and water show that these gases were formed by the carbon dioxide reduction pathway, the same mechanism which has been previously shown to be responsible for microbial methane formation in the marine environment. The isotopic composition of methane in these samples can be closely correlated with the chemical composition of the gas and with water chemistry. The data are interpreted as indicating that isotopically very light methane is found in waters where the residence time of groundwater in the methanogenesis zone was very short relative to the methane production rate. ?? 1988.

  16. Short-term assessment of the sediment deposition rate and water conditions during a rainy season on La Azufrada coral reef, Gorgona Island, Colombia

    Directory of Open Access Journals (Sweden)

    Diego F. Lozano-Cortés

    2014-02-01

    Full Text Available One of the major stresses on corals is the settlement of suspended sediment on their surfaces. This leads to the blocking of light, the covering of the coral mucus surface and an increased risk of disease. For this reason sediment deposition on a reef is considered a highly important variable in coral reef studies. With the use of sediment traps and oceanographic sensors, the sediment deposition rate and water conditions during a rainy season (April-May 2009 on a Tropical Eastern Pacific coral reef (La Azufrada at Gorgona Island in Colombia were investigated. To quantify sediment deposition, sediment traps were established in nine stations along the coral reef (three stations per reef zone: backreef, flat and slope. To minimize disturbance by aquatic organisms in the sediment traps these were filled with hypersaline borax-buffered 10% formaline solution before their deployment; animals found in the filter contents were fixed and stored in a 4% formalin solution, frozen and identified in the laboratory. To determine the water conditions, discrete samples of water from 1 m and 10 m depths were collected using a Niskin bottle. Oceanographic variables (temperature, salinity and dissolved oxygen as well as turbidity, chlorophyll and nutrient concentration (nitrite, nitrate and phosphorus were measured in the samples from both depths. Vertical records of temperature and salinity were carried out with a Seabird-19 CTD nearest to La Azufrada and water transparency was measured using a Secchi disk. We found a mean trap collection rate of 23.30±4.34gm-2d-1 and did not detect a significant difference in the trap collection rate among reef zones. The mean temperature and salinity in the coral reef depth zone (0-10m layer were 26.98±0.19°C and 32.60±0.52, respectively. Fourteen taxonomic groups of invertebrates were detected inside the sediment traps with bivalves and copepods being the most abundant and frequen. The findings presented here constitute

  17. Short-term assessment of the sediment deposition rate and water conditions during a rainy season on La Azufrada coral reef, Gorgona Island, Colombia

    KAUST Repository

    Lozano-Cortés, Diego F

    2014-02-01

    One of the major stresses on corals is the settlement of suspended sediment on their surfaces. This leads to the blocking of light, the covering of the coral mucus surface and an increased risk of disease. For this reason sediment deposition on a reef is considered a highly important variable in coral reef studies. With the use of sediment traps and oceanographic sensors, the sediment deposition rate and water conditions during a rainy season (April-May 2009) on a Tropical Eastern Pacific coral reef (La Azufrada) at Gorgona Island in Colombia were investigated. To quantify sediment deposition, sediment traps were established in nine stations along the coral reef (three stations per reef zone: backreef, flat and slope). To minimize disturbance by aquatic organisms in the sediment traps these were filled with hypersaline borax-buffered 10% formaline solution before their deployment; animals found in the filter contents were fixed and stored in a 4% formalin solution, frozen and identified in the laboratory. To determine the water conditions, discrete samples of water from 1 m and 10 m depths were collected using a Niskin bottle. Oceanographic variables (temperature, salinity and dissolved oxygen) as well as turbidity, chlorophyll and nutrient concentration (nitrite, nitrate and phosphorus) were measured in the samples from both depths. Vertical records of temperature and salinity were carried out with a Seabird-19 CTD nearest to La Azufrada and water transparency was measured using a Secchi disk. We found a mean trap collection rate of 23.30±4.34gm-2d-1 and did not detect a significant difference in the trap collection rate among reef zones. The mean temperature and salinity in the coral reef depth zone (0-10m layer) were 26.98±0.19°C and 32.60±0.52, respectively. Fourteen taxonomic groups of invertebrates were detected inside the sediment traps with bivalves and copepods being the most abundant and frequen. The findings presented here constitute the first report

  18. Origin of stratiform sediment-hosted manganese carbonate ore deposits: Examples from Molango, Mexico, and TaoJiang, China

    Science.gov (United States)

    Okita, P.M.; Shanks, Wayne C.

    1992-01-01

    Carbonate and sulfide minerals from the Molango, Mexico, and TaoJiang, China, Mn deposits display similar and distinctive ??34S and ??13C patterns in intervals of manganese carbonate mineralization. ??13C-values for Mn-bearing carbonate range from -17.8 to +0.5??? (PDB), with the most negative values occurring in high-grade ore zones that are composed predominantly of rhodochrosite. In contrast, calcite from below, within and above Mn-carbonate zones at Molango has ??13C???0??? (PDB). Markedly negative ??13C data indicate that a large proportion of the carbon in Mn-carbonates was derived from organic matter oxidation. Diagenetic reactions using MnO2 and SO2-4 to oxidize sedimentary organic matter were the principle causes of such 12C enrichment. Pyrite content and sulfide ?? 34S-values also show distinctive variations. In unmineralized rocks, very negative ??34S-values (avg. < -21??? CDT) and abundant pyrite content suggest that pyrite formed from diagenetic, bacteriogenic sulfate reduction. In contrast, Mn-bearing horizons typically contain only trace amounts of pyrite (e.g., <0.5 wt% S with ??34S-values 34S-enriched, in some cases to nearly the value for contemporaneous seawater. 34S-enriched pyrite from the Mn-carbonate intervals indicates sulfide precipitation in an environment that underwent extensive SO2-4 reduction, and was largely a closed system with regard to exchange of sulfate and dissolved sulfide with normal seawater. The occasional occurrence of 34S-depleted pyrite within Mn-carbonate zones dominated by 34S-enriched pyrite is evidence that closed-system conditions were intermittent and limited to local pore waters and did not involve entire sedimentary basins. Mn-carbonate precipitation may have occluded porosity in the surficial sediments, thus establishing an effective barrier to SO2-4 exchange with overlying seawater. Similar isotopic and mineralogic characteristics from both the Molango and TaoJiang deposits, widely separated in geologic time and

  19. Reconstruction of eroded and deposited sediment volumes in the floodplains of the embanked River Waal, the Netherlands, for the period 1650 - 1850 AD

    Science.gov (United States)

    Hobo, Noortje; Makaske, Bart; Middelkoop, Hans

    2010-05-01

    The embanked floodplains of the River Waal developed as a result of stepwise downstream migration of meander bends between confining dykes. Accretion in the upstream limb of the outer bend - enhanced by groynes and trees - and erosion in the downstream limb have resulted in a series of successively developed sand bars, separated by secondary channels. On top of the sand bars and the secondary channel fills, fine-grained overbank sediments were deposited. Downstream migration ceased around 1850 AD, when the river bed was fixed by large-scale construction of groynes, and only overbank deposition continued. Eroded and deposited sediment volumes associated with downstream migration are affected by human activities. Goal of the present research is to estimate a sediment budget for a 12-km-long section along the River Waal, by quantifying the amount of erosion and deposition. We estimated these volumes for time slices of 50 years, between 1650 and 1850 AD, in order to be able to assess the variable impact of human interference during this period. To estimate erosion, we created geomorphological maps for all time slices, based on maps dating from the 17th century to present. In these maps, distinction is made between sand bars, residual channels, and older deposits (all sediments deposited before 1650 AD). Comparison between all maps allowed us to calculate the eroded area per time slice. Eroded volumes were hence estimated by multiplying the eroded area by the average river depth at that period, which is assumed to be the erosion depth. For estimation of deposition we used lithological cross-sections. These cross-sections are positioned such that every sand bar and every residual channel is represented in at least one cross-section. In every cross-section isochrones were drawn, based on OSL datings, chronologic interpretation of heavy metal profiles, and the historical maps. These isochrones are used to calculate the thickness of the sand bars, the residual channel fills

  20. Gold and trace element zonation in pyrite using a laser imaging technique: Implications for the timing of gold in orogenic and carlin-style sediment-hosted deposits

    Science.gov (United States)

    Large, R.R.; Danyushevsky, L.; Hollit, C.; Maslennikov, V.; Meffre, S.; Gilbert, S.; Bull, S.; Scott, R.; Emsbo, P.; Thomas, H.; Singh, B.; Foster, J.

    2009-01-01

    Laser ablation ICP-MS imaging of gold and other trace elements in pyrite from four different sediment- hosted gold-arsenic deposits has revealed two distinct episodes of gold enrichment in each deposit: an early synsedimentary stage where invisible gold is concentrated in arsenian diagenetic pyrite along with other trace elements, in particular, As, Ni, Pb, Zn, Ag, Mo, Te, V, and Se; and a later hydrothermal stage where gold forms as either free gold grains in cracks in overgrowth metamorphic and/or hydrothermal pyrite or as narrow gold- arsenic rims on the outermost parts of the overgrowth hydrothermal pyrite. Compared to the diagenetic pyrites, the hydrothermal pyrites are commonly depleted in Ni, V, Zn, Pb, and Ag with cyclic zones of Co, Ni, and As concentration. The outermost hydrothermal pyrite rims are either As-Au rich, as in moderate- to high- grade deposits such as Carlin and Bendigo, or Co-Ni rich and As-Au poor as in moderate- to low-grade deposits such as Sukhoi Log and Spanish Mountain. The early enrichment of gold in arsenic-bearing syngenetic to diagenetic pyrite, within black shale facies of sedimentary basins, is proposed as a critical requirement for the later development of Carlin-style and orogenic gold deposits in sedimentary environments. The best grade sediment-hosted deposits appear to have the gold climax event, toward the final stages of deformation-related hydrothermal pyrite growth and fluid flow. ?? 2009 Society of Economic Geologists, Inc.

  1. Grain-size evolution in suspended sediment and deposits from the 2004 and 2008 controlled-flood experiments in Marble and Grand Canyons, Arizona

    Science.gov (United States)

    Draut, Amy E.; Topping, David J.; Rubin, David M.; Wright, Scott A.; Schmidt, John C.

    2010-01-01

    Since the closure of Glen Canyon Dam in 1963, the hydrology, sediment supply, and distribution and size of modern alluvial deposits in the Colorado River through Grand Canyon have changed substantially (e.g., Howard and Dolan, 1981; Johnson and Carothers, 1987; Webb et al., 1999; Rubin et al., 2002; Topping et al., 2000, 2003; Wright et al., 2005; Hazel et al., 2006). The dam has reduced the fluvial sediment supply at the upstream boundary of Grand Canyon National Park by about 95 percent. Regulation of river discharge by dam operations has important implications for the storage and redistribution of sediment in the Colorado River corridor. In the absence of natural floods, sediment is not deposited at elevations that regularly received sediment before dam closure. There has been a systemwide decrease in the size and number of subaerially exposed fluvial sand deposits since the 1960s, punctuated by episodic aggradation during the exceptional high-flow intervals in the early 1980s and by sediment input from occasional tributary floods (Beus and others, 1985; Schmidt and Graf, 1990; Kearsley et al., 1994; Schmidt et al., 2004; Wright et al., 2005; Hazel et al., 2006). Fluvial sandbars are an important component of riparian ecology that, among other functions, enclose eddy backwaters that form native-fish habitat, provide a source for eolian sand that protects some archaeological sites, and are used as campsites by thousands of river-runners annually (Rubin et al., 1990; Kearsley et al., 1994; Neal et al., 2000; Wright et al., 2005; Draut and Rubin, 2008).

  2. GEOLOGY AND DEPOSITIONAL ENVIRONMENT OF CAMPANO-MAASTRICHTIAN SEDIMENTS IN THE ANAMBRA BASIN, SOUTHEASTERN NIGERIA: EVIDENCE FROM FIELD RELATIONSHIP AND SEDIMENTOLOGICAL STUDY

    Directory of Open Access Journals (Sweden)

    A. E Salufu

    2009-12-01

    Full Text Available The study area lies within the Anambra Basin and it is made up of Enugu Shale, Mamu Formation, Ajali Sandstone, and Nsukka Formation. This study aimed at determining the geology and depositional environmental of these formations through field relationship and grain size distribution morphologic studies.The field data shows Enugu Shale as fissile, light grey with extraformational clast which graded into Mamu Formation whichis made up of shale, coal and sandy shale. It passes upward into Ajali Sandstone which is characterized by cross beds, Herringbonestructures and Ophiomorpha burrows. The youngest formation within the basin is Nsukka Formation.The granulometric study of Mamu Formation shows fine to medium grains, coarse, medium to fine grain for Mamu and Ajali Formation respectively. The standard deviation indicates poorly sorted. The kurtosis shows leptokurtic, platykurtic to very leptokurtic for both while the skewness values indicate positive and symmetrical in all except for Ajali Sandstone that is negatively skewed.The bivariate and the multivariate results reveal shallow marine and fluvial deposits for both Mamu Formation and Ajali Sandstone respectively. The paleocurrent direction of Ajali Sandstone indicates southwest while the provenance is northeast.The fissility of Enugu Shale suggests that it was deposited in low energy environment, distal to proximal lagoon environment.The presence of extraformatonal clast within Enugu Shale indicates fluvial incursion. However, the textural analysis of Mamu Formation suggests a sediment deposited in a low energy environment which favoured deposition of fine to medium size sediments that is, estuary environment. Textural result of Ajali Sandstone in the study area coupled with the field data such as Herring-bone structures, and Ophiomorpha burrows, revealed that Ajali Sandstone was deposited in a tidal environment probably littoral environment. While the light grey colour observed in the

  3. Mio Pliocene volcaniclastic deposits in the Famatina Ranges, southern Central Andes: A case of volcanic controls on sedimentation in broken foreland basins

    Science.gov (United States)

    Martina, Federico; Dávila, Federico M.; Astini, Ricardo A.

    2006-04-01

    A well-constrained record of Miocene-Pliocene explosive volcanism is preserved within the broken foreland of Western Argentina along the Famatina Ranges. This paper focuses on the volcaniclastic record known as the Río Blanco member of the El Durazno Formation. Three facies can be recognized in the study area: (1) massive tuffs; (2) volcaniclastic conglomerates and (3) pumiceous sandstones. These facies are interpreted as primary pyroclastic flow deposits (ignimbrites) and reworked volcanogenic deposits within interacting volcanic-fluvial depositional systems. Alternation between ignimbrites and volcanogenic sandstones and conglomerates suggest a recurrent pattern of sedimentation related to recurrent volcanic activity. Considering the facies mosaic and relative thicknesses of facies, short periods of syn-eruption sedimentation (volcaniclastic deposits) seem to have been separated by longer inter-eruption periods, where normal stream-flow processes were dominant. The volcaniclastic component decreases up-section, suggesting a gradual reduction in volcanic activity. The mean sedimentation rate of the Río Blanco member is higher (0.44 mm/year) than those obtained for the underlying and overlying units. This increase cannot be fully explained by foreland basement deformation and tectonic loading. Hence, we propose subsidence associated with volcanic activity as the causal mechanism. Volcanism would have triggered additional accommodation space through coeval pyroclastic deposition, modification of the stream equilibrium profile, flexural loading of volcanoes, and thermal processes. These mechanisms may have favored the preservation of volcaniclastic beds in the high-gradient foreland system of Famatina during the Mio-Pliocene. Thus, the Río Blanco member records the response of fluvial systems to large, volcanism-induced sediment loads.

  4. Role of urban surface roughness in road-deposited sediment build-up and wash-off

    Science.gov (United States)

    Zhao, Hongtao; Jiang, Qian; Xie, Wenxia; Li, Xuyong; Yin, Chengqing

    2018-05-01

    Urban road surface roughness is one of the most important factors in estimation of surface runoff loads caused by road-deposited sediment (RDS) wash-off and design of its control measures. However, because of a lack of experimental data to distinguish the role of surface roughness, the effects of surface roughness on RDS accumulation and release are not clear. In this study, paired asphalt and concrete road surfaces and rainfall simulation designs were used to distinguish the role of surface roughness in RDS build-up and wash-off. Our results showed that typical asphalt surfaces often have higher depression depths than typical concrete surfaces, indicating that asphalt surfaces are relatively rougher than concrete surface. Asphalt surfaces can retain a larger RDS amount, relative higher percentage of coarser particles, larger RDS wash-off loads, and lower wash-off percentage, than concrete surfaces. Surface roughness has different effects in RDS motilities with different particle sizes during rainfall runoff, and the settleable particles (44-149 μm) were notably influenced by it. Furthermore, the first flush phenomenon tended to be greater on relatively smooth surfaces than relatively rough surfaces. Overall, surface roughness plays an important role in influencing the complete process of RDS build-up and wash-off on different road characteristics.

  5. Qualitative assessment of selected areas of the world for undiscovered sediment-hosted stratabound copper deposits: Chapter Y in Global mineral resource assessment

    Science.gov (United States)

    Zientek, Michael L.; Wintzer, Niki E.; Hayes, Timothy S.; Parks, Heather L.; Briggs, Deborah A.; Causey, J. Douglas; Hatch, Shyla A.; Jenkins, M. Christopher; Williams, David J.; Zientek, Michael L.; Hammarstrom, Jane M.; Johnson, Kathleen M.

    2015-12-14

    A qualitative mineral resource assessment of sediment-hosted stratabound copper mineralized areas for undiscovered copper deposits was performed for 10 selected areas of the world. The areas, in alphabetical order, are (1) Belt-Purcell Basin, United States and Canada; (2) Benguela and Cuanza Basins, Angola; (3) Chuxiong Basin, China; (4) Dongchuan Group rocks, China; (5) Egypt–Israel–Jordan Rift, Egypt, Israel, and Jordan; (6) Maritimes Basin, Canada; (7) Neuquén Basin, Argentina; (8) Northwest Botswana Rift, Botswana and Namibia; (9) Redstone Copperbelt, Canada; and (10) Salta Rift System, Argentina. This assessment (1) outlines the main characteristics of the areas, (2) classifies known deposits by deposit model subtypes, and (3) ranks the areas according to their potential to contain undiscovered copper deposits.

  6. Texture, mineralogy and geochemistry of the continental slope sediments in front of Los Tuxtlas, Gulf of Mexico, Mexico: implications on weathering, origin and depositional environments

    Science.gov (United States)

    Marca-Castillo, M. E.; Armstrong-Altrin, J.

    2017-12-01

    The textural analysis, mineralogy and geochemistry of two sediment cores recovered from the deep water zone of the southwestern part of the Gulf of Mexico ( 1666 and 1672 m water depth) were studied to infer the provenance and depositional behavior. The textural analysis revealed that both cores are dominated by silt, which occupy more than 50% in both samples and the clay occupy 40%. The petrographic analysis revealed remains of biogenic origin sediments and lithic fragments with an angular shape and low sphericity, indicating a low energy environment and therefore a low level of weathering in the sediment, which suggests that the sediments were not affected by transport and derived from a nearby source rock. In both cores quartz fragments were identified; also volcanic lithic and pyroxenes fragments, which are rocks of intermediate composition and are generally associated with the volcanic activity of the continental margins. SEM-EDS studies showed that the analysed samples have concentrations of minerals such as barite, gibbsite, kaolinite, grossular, magnetite, plagioclase and chlorite, which are probably derived from the mainland to the deep sea zone. In the trace element analysis it was observed a low Sc content, while Co, Ni, V and Cu are slightly enriched with respect to the upper continental crust; this enrichment is related to sediments from intermediate sources. The sediments are classified as shale in the log (SiO2 / Al2O3) - log (Fe2O / K2O) diagram. The fine particles of the shale indicate that a deposit occurred as a result of the gradual sedimentation due to relatively non-turbulent currents, which is consistent with the petrographic analysis. The geochemical features of major and trace elements suggest sediments were derived largely from the natural andesite erosion of coastal regions along the Gulf of Mexico. High values of Fe2O3 and MnO are observed in the upper intervals, reflecting the influence of volcanic sediments. The major element

  7. Evaluation of heavy metals transfer: impact of a dredged sediment deposit on a on-polluted soil; Migration des polluants metalliques: cas d'un depot de sediments contamines sur un sol non pollue

    Energy Technology Data Exchange (ETDEWEB)

    Vauleon, C.; Laboudigue, A. [Centre National de Recherche sur les Sites et Sols Pollues, CNRSSP, 59 - Douai (France); Tiffreau, Ch. [CEA Cadarache, 13 - Saint Paul lez Durance (France)

    2001-07-01

    In many countries and especially in the North of France, inland waterways need to be dredged regularly to provide a high quality environment for customers, staff and local communities. However, dredging operations generate yearly large quantities of sediments, which in spite of their high pollutant contents, are often stored in non-specific sites. Thus, the threat of a spreading contamination for the surrounding environment is important. In order to evaluate this potential risk and to quantify the transfer of heavy metals from the dredged layer to the non-polluted soil below, an interdisciplinary research project was undertaken including, (i) the monitoring of an experimental sediment deposit, (ii) the microscopic study of metal distribution inside this deposit, (iii) the evaluation of microbial activity, (iv) the impact of natural vegetation growth on metal migration. Up to now, the main processes identified (oxidation of sulphur compounds, vertical migration of Zinc) allowed us to make several recommendations for the future management of dredged sediments by: (i) controlling the oxidation processes during dredging operations or (ii) assessing the high neutralizing capacity of the local environment of deposition. Moreover, an adequate vegetation management can reduce the heavy metals migration to groundwater's with maximum efficiency and at low costs. (author)

  8. Impaired Short-Term Functioning of a Benthic Community from a Deep Norwegian Fjord Following Deposition of Mine Tailings and Sediments

    Directory of Open Access Journals (Sweden)

    Lisa Mevenkamp

    2017-05-01

    Full Text Available The extraction of minerals from land-based mines necessitates the disposal of large amounts of mine tailings. Dumping and storage of tailings into the marine environment, such as fjords, is currently being performed without knowing the potential ecological consequences. This study investigated the effect of short-term exposure to different deposition depths of inert iron ore tailings (0.1, 0.5, and 3 cm and dead subsurface sediment (0.5 and 3 cm on a deep water (200 m fjord benthic assemblage in a microcosm experiment. Biotic and abiotic variables were measured to determine structural and functional changes of the benthic community following an 11 and 16 day exposure with tailings and dead sediment, respectively. Structural changes of macrofauna, meiofauna, and bacteria were measured in terms of biomass, density, community composition and mortality while measures of oxygen penetration depth, sediment community oxygen consumption and 13C-uptake and processing by biota revealed changes in the functioning of the system. Burial with mine tailings and natural sediments modified the structure and functioning of the benthic community albeit in a different way. Mine tailings deposition of 0.1 cm and more resulted in a reduced capacity of the benthic community to remineralize fresh 13C-labeled algal material, as evidenced by the reduced sediment community oxygen consumption and uptake rates in all biological compartments. At 3 cm of tailings deposition, it was evident that nematode mortality was higher inside the tailings layer, likely caused by reduced food availability. In contrast, dead sediment addition led to an increase in oxygen consumption and bacterial carbon uptake comparable to control conditions, thereby leaving deeper sediment layers anoxic and in turn causing nematode mortality at 3 cm deposition. This study clearly shows that even small levels (0.1 cm of instantaneous burial by mine tailings may significantly reduce benthic ecosystem

  9. Syn-eruptive, soft-sediment deformation of deposits from dilute pyroclastic density current: triggers from granular shear, dynamic pore pressure, ballistic impacts and shock waves

    Science.gov (United States)

    Douillet, G. A.; Taisne, B.; Tsang-Hin-Sun, E.; Muller, S. K.; Kueppers, U.; Dingwell, D. B.

    2015-05-01

    Soft-sediment deformation structures can provide valuable information about the conditions of parent flows, the sediment state and the surrounding environment. Here, examples of soft-sediment deformation in deposits of dilute pyroclastic density currents are documented and possible syn-eruptive triggers suggested. Outcrops from six different volcanoes have been compiled in order to provide a broad perspective on the variety of structures: Soufriere Hills (Montserrat), Tungurahua (Ecuador), Ubehebe craters (USA), Laacher See (Germany), and Tower Hill and Purrumbete lakes (both Australia). The variety of features can be classified in four groups: (1) tubular features such as pipes; (2) isolated, laterally oriented deformation such as overturned or oversteepened laminations and vortex-shaped laminae; (3) folds-and-faults structures involving thick (>30 cm) units; (4) dominantly vertical inter-penetration of two layers such as potatoids, dishes, or diapiric flame-like structures. The occurrence of degassing pipes together with basal intrusions suggest fluidization during flow stages, and can facilitate the development of other soft-sediment deformation structures. Variations from injection dikes to suction-driven, local uplifts at the base of outcrops indicate the role of dynamic pore pressure. Isolated, centimeter-scale, overturned beds with vortex forms have been interpreted to be the signature of shear instabilities occurring at the boundary of two granular media. They may represent the frozen record of granular, pseudo Kelvin-Helmholtz instabilities. Their recognition can be a diagnostic for flows with a granular basal boundary layer. Vertical inter-penetration and those folds-and-faults features related to slumps are driven by their excess weight and occur after deposition but penecontemporaneous to the eruption. The passage of shock waves emanating from the vent may also produce trains of isolated, fine-grained overturned beds that disturb the surface bedding

  10. Intelligent street lighting clustering

    NARCIS (Netherlands)

    Verhoeven, R.; Jovanovic, N.; Lukkien, J.J.

    2014-01-01

    The advances in dynamic street lighting introduce new functionality for control and maintenance of the street lighting infrastructure. Vital elements in this infrastructure are the powerful controlling devices that control separate groups of light poles and collect information from the system. For

  11. Sedimentary record of polycyclic aromatic hydrocarbons in a sediment core from a maar lake, Northeast China: evidence in historical atmospheric deposition.

    Science.gov (United States)

    Guan, Yu-Feng; Sun, Jian-Lin; Ni, Hong-Gang; Guo, Jian-Yang

    2012-09-01

    A maar lake is an excellent ecosystem to study the atmospheric deposition of pollutants, as its contaminants are primarily by atmospheric deposition. In this study, a sediment core from Sihailongwan Maar Lake, Northeast China, was collected and the historical atmospherically deposited polycyclic aromatic hydrocarbons (PAHs) were analyzed. The concentrations of TPAHs (the sum of the US EPA proposed 16 priority PAHs, excluding naphthalene and pyrene) ranged from 473.9 to 2289 ng g(-1) with a slow increasing stage in the deeper sediments and a sharp increasing stage in the upper sediments. The input rate of TPAHs, especially that of PAH(9) (the sum of fluoranthene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenzo(ah)anthrathene, and benzo(ghi)perylene), correlated well to the Chinese historical socioeconomic data. This indicates that sediment PAHs were mainly derived from human activities and PAH(9) can be regarded as a better indicator of the local socioeconomic development. Source identification suggested that PAHs were originated primarily from mixed sources (e.g., coal and biomass burning and petroleum combustion), except for perylene which was mostly of diagenetic origin. In addition, the down-core PAHs profile clearly illustrated that PAHs sources in Northeast China experienced a transformation from low- and moderate temperature to high-temperature combustion processes, especially after the late 1980s. Additionally, an ecological risk assessment using two redefined biological thresholds (TEQ(ERL) and TEQ(ERM)) indicated that most of the PAHs measured in the present sediment core would not cause an immediate toxic effect; only FLU and PHEN are a potential source of concern for biological impairment.

  12. Post-depositional redistribution of trace metals in reservoir sediments of a mining/smelting-impacted watershed (the Lot River, SW France)

    International Nuclear Information System (INIS)

    Audry, Stephane; Grosbois, Cecile; Bril, Hubert; Schaefer, Joerg; Kierczak, Jakub; Blanc, Gerard

    2010-01-01

    Mining/smelting wastes and reservoir sediment cores from the Lot River watershed were studied using mineralogical (XRD, SEM-EDS, EMPA) and geochemical (redox dynamics, selective extractions) approaches to characterize the main carrier phases of trace metals. These two approaches permitted determining the role of post-depositional redistribution processes in sediments and their effects on the fate and mobility of trace metals. The mining/smelting wastes showed heterogeneous mineral compositions with highly variable contents of trace metals. The main trace metal-bearing phases include spinels affected by secondary processes, silicates and sulfates. The results indicate a clear change in the chemical partitioning of trace metals between the reservoir sediments upstream and downstream of the mining/smelting activities, with the downstream sediments showing a 2-fold to 5-fold greater contribution of the oxidizable fraction. This increase was ascribed to stronger post-depositional redistribution of trace metals related to intense early diagenetic processes, including dissolution of trace metal-bearing phases and precipitation of authigenic sulfide phases through organic matter (OM) mineralization. This redistribution is due to high inputs (derived from mining/smelting waste weathering) at the water-sediment interface of (i) dissolved SO 4 promoting more efficient OM mineralization, and (ii) highly reactive trace metal-bearing particles. As a result, the main trace metal-bearing phases in the downstream sediments are represented by Zn- and Fe-sulfides, with minor occurrence of detrital zincian spinels, sulfates and Fe-oxyhydroxides. Sequestration of trace metals in sulfides at depth in reservoir sediments does not represent long term sequestration owing to possible resuspension of anoxic sediments by natural (floods) and/or anthropogenic (dredging, dam flush) events that might promote trace metal mobilization through sulfide oxidation. It is estimated that, during a major

  13. Influence of low impact development construction on pollutant process of road-deposited sediments and associated heavy metals.

    Science.gov (United States)

    Ma, Yukun; Gong, Manli; Zhao, Hongtao; Li, Xuyong

    2018-02-01

    Intense Low-Impact Development (LID) construction in China could lead to increasingly severe stormwater and receiving water pollution due to the lack of appropriate regulation for mitigating pollution from LID construction. Samples of road-deposited sediments (RDS) were collected from 50 study sites at seven LID construction stages and four road hierarchies to analyze the pollution process and determine the size of the region influenced by LID construction. Six heavy metals were analyzed, and the RDS index model was adopted to estimate the potential heavy metal load washed off by stormwater runoff. Analysis of variance revealed that the excavation and gravel filling of rain gardens and excavation of porous pavements were critical LID construction stages that contributed the largest masses of RDS per unit area to road surfaces. Although the concentration of heavy metals at LID construction sites was lower than at sites without LID construction, the load of heavy metals washed off from LID construction was much higher. In addition, the sizes of regions influenced by accumulated RDS from LID construction descended in the following order: arterial road (600-775m)>collector road (150-200m)>access road (100-150m)>laneway (20-30m). According to the characteristics of LID construction at the study sites, the potential total solid loads in stormwater throughout China were estimated to reach 36,694t by 2020 and 146,777t by 2030. According to the results of analysis, several recommendations are provided for designing LID construction regulations to mitigate stormwater pollution. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. U-Pb Detrital Zircon Geochronologic Constraints on Depositional Age and Sediment Source Terrains of the Late Paleozoic Tepuel-Genoa Basin

    Science.gov (United States)

    Griffis, N. P.; Montanez, I. P.; Isbell, J.; Gulbranson, E. L.; Wimpenny, J.; Yin, Q. Z.; Cúneo, N. R.; Pagani, M. A.; Taboada, A. C.

    2014-12-01

    The late Paleozoic Ice Age (LPIA) is the longest-lived icehouse of the Phanerozoic and the only time a metazoan dominated and vegetated world transitioned from an icehouse climate into a greenhouse. Despite several decades of research, the timing, extent of glaciation and the location of ice centers remain unresolved, which prohibits reconstruction of ice volume. The Permo-Carboniferous sediments in the Tepuel-Genoa Basin, Patagonia contains a near complete record of sedimentation from the lower Carboniferous through lower Permian. Outsized clasts, thin pebble-rich diamictites and slumps represent the last of the late Paleozoic glacially influenced deep-water marine sediments in the Mojón de Hierro Fm. and the Paleozoic of Patagonia. U-Pb analysis of detrital zircons separated from slope sediments reveal groupings (20 myr bins, n≥5 zircons) with peak depositional ages of 420, 540 to 660 and 1040 Ma. Zircon age populations recovered from the Mojón de Hierro Fm. compare well with bedrock ages of the Deseado Massif of SE Patagonia, suggesting this may be a potential source of sediments. The maximum depositional age of the sediments is 306.05 ± 3.7 Ma (2σ) as determined by the median age of the two youngest concordant zircons that overlap in error. The youngest zircon from the analysis yields a 238U/206Pb age of 301.3 ± 4.5 Ma (2σ; MSWD = 2.3). Younger zircons from the analysis compare well with the age of granite bedrock exposed along the basin margin to the E-NE suggesting they may reflect a more proximal source. These data, which indicate a maximum age of late Carboniferous for the Mojón de Hierro Fm, provide the first geochemical constraints for the timing of final deposition of glaciomarine sediments in the Tepuel-Genoa Basin, and contributes to the biostratigraphic correlation of the late Paleozoic succession in Patagonia with other key LPIA basins that has thus far been hindered by faunal provincialism.

  15. Sediment deposition from Hurricane Rita on Hackberry Beach chenier in southwestern Louisiana: Chapter 6E in Science and the storms-the USGS response to the hurricanes of 2005

    Science.gov (United States)

    Faulkner, Stephen; Barrow, Wylie; Doyle, Thomas; Baldwin, Michael; Michot, Thomas; Wells, Christopher; Jeske, Clint

    2007-01-01

    Hurricane Rita significantly impacted the chenier forests of southwestern Louisiana, an important habitat for Neotropical migratory birds. Sediment deposition was measured along transects at Hackberry Beach chenier, and Rita's effects on chenier structure and morphology were determined.

  16. Sequential extraction of heavy metals from urban dust and street sediments. Pt. 1. Sequential extraction of heavy metals in micro samples; Sequentielle Schwermetallextraktion aus Staubniederschlaegen und Strassensedimenten. T. 1. Sequentielle Schwermetallextraktion von Mikroproben

    Energy Technology Data Exchange (ETDEWEB)

    Heiser, U.; Norra, S.; Stueben, D.; Wagner, M. von [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Petrographie und Geochemie

    1999-01-01

    For the application of sequential extraction of heavy metals from samples that can only be obtained in amounts of a few milligrams (micro samples, e.g. airborne dust fallout), the method after Zeien and Bruemmer (1989) was progressed. A down scale to 1:100 was carried out and the accuracy of this method with variable sample amounts of about 20 mg and an extraction volume of 500 {mu}l was proofed with standard soil samples. The influence of variable extraction ratios (ratio of sample amount and volume of extraction solvent) and the influence of intensive treatment of dust sampled by the Bergerhoff-method (VDI 2119/2, 1972) prior sequential extraction, was within the precision of measurement of our method. Thus, we showed that sequential extraction can be applied for the investigation of heavy metal mobilization in micro samples with variable sample amounts. A first application of our method for microsamples was carried out to investigate airborne dust fallout and street sediments at two urban sites where different heavy metal immission rates due to traffic influence occur. These investigations will be presented in part 2 (`Sequential extraxction of heavy metals from urban dust`). (orig.) [Deutsch] Fuer die Anwendung der sequentiellen Schwermetallextraktion auf Proben, die nur im Milligramm-Bereich erhalten werden koennen (Mikroproben, wie z.B. Staubniederschlaege), wurde die Methode von Zeien und Bruemmer (1989) weiterentwickelt. Der Extraktionsmassstab wurde um den Faktor 1:100 verringert und die Reproduzierbarkeit des Verfahrens mit variablen Probenmengen um 20 mg und einem Extraktionsvolumen von 500 {mu}l mit Hilfe von Standardboeden nachgewiesen. Moegliche Einfluesse variabler Extraktionsverhaeltnisse (Verhaeltnis von Probenmenge zu Extraktionsvolumen) sowie eine aufwendige Vorbehandlung von Staubproben, die nach der Bergerhoff-Methode (VDI 2119/2, 1972) gesammelt wurden, lagen bei diesen Untersuchungen weitgehend im Variationsbereich des Verfahrens. Die

  17. Legacy sediment, lead, and zinc storage in channel and floodplain deposits of the Big River, Old Lead Belt Mining District, Missouri, USA

    Science.gov (United States)

    Pavlowsky, Robert T.; Lecce, Scott A.; Owen, Marc R.; Martin, Derek J.

    2017-12-01

    The Old Lead Belt of southeastern Missouri was one of the leading producers of Pb ore for more than a century (1869-1972). Large quantities of contaminated mine waste have been, and continue to be, supplied to local streams. This study assessed the magnitude and spatial distribution of mining-contaminated legacy sediment stored in channel and floodplain deposits of the Big River in the Ozark Highlands of southeastern Missouri. Although metal concentrations decline downstream from the mine sources, the channel and floodplain sediments are contaminated above background levels with Pb and Zn along its entire 171-km length below the mine sources. Mean concentrations in floodplain cores > 2000 mg kg- 1 for Pb and > 1000 mg kg- 1 for Zn extend 40-50 km downstream from the mining area in association with the supply of fine tailings particles that were easily dispersed downstream in the suspended load. Mean concentrations in channel bed and bar sediments ranging from 1400 to 1700 mg kg- 1 for Pb extend 30 km below the mines, while Zn concentrations of 1000-3000 mg kg- 1 extend 20 km downstream. Coarse dolomite fragments in the 2-16 mm channel sediment fraction provide significant storage of Pb and Zn, representing 13-20% of the bulk sediment storage mass in the channel and can contain concentrations of > 4000 mg kg- 1 for Pb and > 1000 mg kg- 1 for Zn. These coarse tailings have been transported a maximum distance of only about 30 km from the source over a period of 120 years for an average of about 250 m/y. About 37% of the Pb and 9% of the Zn that was originally released to the watershed in tailings wastes is still stored in the Big River. A total of 157 million Mg of contaminated sediment is stored along the Big River, with 92% of it located in floodplain deposits that are typically contaminated to depths of 1.5-3.5 m. These contaminated sediments store a total of 188,549 Mg of Pb and 34,299 Mg of Zn, of which 98% of the Pb and 95% of the Zn are stored in floodplain

  18. A tale of two storms: Surges and sediment deposition from Hurricanes Andrew and Wilma in Florida’s southwest coast mangrove forests: Chapter 6G in Science and the storms-the USGS response to the hurricanes of 2005

    Science.gov (United States)

    Smith, Thomas J.; Anderson, Gordon H.; Tiling, Ginger

    2007-01-01

    Hurricanes can be very different from each other. Here we examine the impacts that two hurricanes, Andrew and Wilma, had in terms of storm surge and sediment deposition on the southwest coast of Florida. Although Wilma was the weaker storm, it had the greater impact. Wilma had the higher storm surge over a larger area and deposited more sediment than did Andrew. This effect was most likely due to the size of Wilma's eye, which was four times larger than that of Andrew.

  19. Sediment Sources, Depositional Environment, and Diagenetic Alteration of the Marcellus Shale, Appalachian Basin, USA: Nd, Sr, Li and U Isotopic Constraints

    Science.gov (United States)

    Phan, T. T.; Capo, R. C.; Gardiner, J. B.; Stewart, B. W.

    2017-12-01

    The organic-rich Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, is a major target of natural gas exploration. Constraints on local and regional sediment sources, depositional environments, and post-depositional processes are essential for understanding the evolution of the basin. In this study, multiple proxies, including trace metals, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U and Li isotopes were applied to bulk rocks and authigenic fractions of the Marcellus Shale and adjacent limestone/sandstone units from two locations separated by 400 km. The range of ɛNd values (-7.8 to -6.4 at 390 Ma) is consistent with a clastic sedimentary component derived from a well-mixed source of fluvial and eolian material of the Grenville orogenic belt. The Sm-Nd isotope system and bulk REE distributions appear to have been minimally affected by post-depositional processes, while the Rb-Sr isotope system shows evidence of limited post-depositional redistribution. While REE are primarily associated with silicate minerals (80-95%), REE patterns of sequentially extracted fractions reflect post-depositional alteration at the intergranular scale. Although the chemical index of alteration (CIA = 54 to 60) suggests the sediment source was not heavily weathered, Li isotope data are consistent with progressively increasing weathering of the source region during Marcellus Shale deposition. δ238U values in bulk shale and reduced phases (oxidizable fraction) are higher than those of modern seawater and upper crust. The isotopically heavy U accumulated in these authigenic phases can be explained by the precipitation of insoluble U in anoxic/euxinic bottom water. Unlike carbonate cement within the shale, the similarity between δ238U values and REE patterns of the limestone units and those of modern seawater indicates that the limestone formed under open ocean (oxic) conditions.

  20. Chemistry of marine sediments

    International Nuclear Information System (INIS)

    Yen, T.F.

    1977-01-01

    Some topics considered are as follows: characterization of sediments in the vicinity of offshore petroleum production; thermal alteration experiments on organic matter in recent marine sediments as a model for petroleum genesis; composition of polluted bottom sediments in Great Lakes harbors; distribution of heavy metals in sediment fractions; recent deposition of lead off the coast of southern California; release of trace constituents from sediments resuspended during dredging operations; and migration of chemical constituents in sediment-seawater interfaces

  1. The ESR age of Portlandia arctica shells from glacial deposits of Central Latvia . an answer to a controversy on the age and genesis of their enclosing sediments

    Science.gov (United States)

    Molodkov, Anatoly; Dreimanis, Aleksis; ĀBoltiņš, Ojars; Raukas, Anto

    The occurrence of Portlandia arctica shells in glacigenic sediments of Central Latvia had created a controversy in many publications about (1) their age ranging from the Holsteinian to the Late Weichselian and (2) the genesis of their enclosing sediments: glacial, glaciomarine or marine. Our reinvestigation of the main object of controversy, the Lı¯čupe site, leads to a conclusion that the sedimentary package of diamictons, clays and sands containing Portlandia arctica shells and marine microfossils is a large glacial raft that had been transported and deposited by the Riga lobe during the Weichselian. The electron spin resonance (ESR) ages on five sets of Portlandia arctica shells from the Lı¯čupe and Daugmales Tomēni sites range from 86.0±6.8 to 105.0±9.2 ka BP. These ESR age determinations and the cool climate indicators of the associated microflora and microfauna suggest that their source sediments, probably in the Gulf of Riga, are marine clays of Early Weichselian age, probably correlative to the Brørup Interstadial. In Central Latvia Portlandia arctica shells and their enclosing clay occur resedimented or translocated in glacial deposits during Weichselian glacial advances.

  2. Unravelling mixed sediment signals in the floodplains of the Rhine catchment using end member modelling of grain size distributions

    NARCIS (Netherlands)

    Erkens, G.; Toonen, W.H.J.; Cohen, K.M.; Prins, M.A.

    2013-01-01

    During sediment transport downstream, river systems mix sediments from different parts of their catchments. During deposition, sediments are often unmixed again in different depositional environments (facies). During fluvial transport, between erosion and deposition of sediment, the sediment is

  3. Regional setting, distribution and genesis of surficial uranium deposits in calcretes and associated sediments in Western Australia

    International Nuclear Information System (INIS)

    Butt, C.R.M.; Mann, A.W.; Horwitz, R.C.

    1984-01-01

    Surficial uranium deposits in Western Australia are largely in the Yilgarn Block in areas of Archean granitoids and greenstones, and in the Gascoyne Province in Proterozoic granites and gneisses. The region has had a long weathering history marked by continuous planation developing a regolith up to 100 metres thick. The distribution of calcrete type uranium deposits is controlled by geologic as well as weathering, erosion and climatic factors. Valley, playa and terrace deposits are recognized. The principal known surficial uranium deposit, Yeelirrie, occurs in the Yilgarn block as a valley deposit. (author)

  4. Sediment Resuspension and Deposition on Seagrass Leaves Impedes Internal Plant Aeration and Promotes Phytotoxic H2S Intrusion.

    Science.gov (United States)

    Brodersen, Kasper E; Hammer, Kathrine J; Schrameyer, Verena; Floytrup, Anja; Rasheed, Michael A; Ralph, Peter J; Kühl, Michael; Pedersen, Ole

    2017-01-01

    HIGHLIGHTS: Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H 2 S. Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced light availability and the settling of suspended particles onto seagrass leaves potentially impeding gas exchange with the surrounding water. We used microsensors to determine O 2 fluxes and diffusive boundary layer (DBL) thickness on leaves of the seagrass Zostera muelleri with and without fine sediment particles, and combined these laboratory measurements with in situ microsensor measurements of tissue O 2 and H 2 S concentrations. Net photosynthesis rates in leaves with fine sediment particles were down to ~20% of controls without particles, and the compensation photon irradiance increased from a span of 20-53 to 109-145 μmol photons m -2 s -1 . An ~2.5-fold thicker DBL around leaves with fine sediment particles impeded O 2 influx into the leaves during darkness. In situ leaf meristematic O 2 concentrations of plants exposed to fine sediment particles were lower than in control plants and exhibited long time periods of complete meristematic anoxia during night-time. Insufficient internal aeration resulted in H 2 S intrusion into the leaf meristematic tissues when exposed to sediment resuspension even at relatively high night-time water-column O 2 concentrations. Fine sediment particles that settle on seagrass leaves thus negatively affect internal tissue aeration and thereby the plants' resilience against H 2 S intrusion.

  5. Sediment Resuspension and Deposition on Seagrass Leaves Impedes Internal Plant Aeration and Promotes Phytotoxic H2S Intrusion

    Directory of Open Access Journals (Sweden)

    Kasper E. Brodersen

    2017-05-01

    Full Text Available HIGHLIGHTS:Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H2S.Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced light availability and the settling of suspended particles onto seagrass leaves potentially impeding gas exchange with the surrounding water. We used microsensors to determine O2 fluxes and diffusive boundary layer (DBL thickness on leaves of the seagrass Zostera muelleri with and without fine sediment particles, and combined these laboratory measurements with in situ microsensor measurements of tissue O2 and H2S concentrations. Net photosynthesis rates in leaves with fine sediment particles were down to ~20% of controls without particles, and the compensation photon irradiance increased from a span of 20–53 to 109–145 μmol photons m−2 s−1. An ~2.5-fold thicker DBL around leaves with fine sediment particles impeded O2 influx into the leaves during darkness. In situ leaf meristematic O2 concentrations of plants exposed to fine sediment particles were lower than in control plants and exhibited long time periods of complete meristematic anoxia during night-time. Insufficient internal aeration resulted in H2S intrusion into the leaf meristematic tissues when exposed to sediment resuspension even at relatively high night-time water-column O2 concentrations. Fine sediment particles that settle on seagrass leaves thus negatively affect internal tissue aeration and thereby the plants' resilience against H2S intrusion.

  6. Effect of depositional environment and sources of pollution on uranium concentration in sediment, coral, algae and seagrass species from the Gulf of Aqaba (Red Sea)

    International Nuclear Information System (INIS)

    Abu-Hilal, A.H.

    1994-01-01

    Uranium concentrations were determined in sediment samples, four hard and two soft corals, one seagrass and four species of algae collected from phosphate-polluted sites in the northern reef area of the Gulf of Aqaba. High uranium concentrations were found in all samples examined from a phosphate-polluted site near a phosphate loading berth compared to the unpolluted ones. Uranium levels, U/Ca ratios, concentration and discrimination factors were also high compared to those reported from other regions of the world. The effects of the exported raw phosphate powder as the main source of pollution and depositional environment on the concentration of uranium in the examined species are discussed. (Author)

  7. Geochemical constraints on the provenance and depositional environment of the Messinian sediments, onshore Nile Delta, Egypt: Implications for the late Miocene paleogeography of the Mediterranean

    Science.gov (United States)

    Leila, Mahmoud; Moscariello, Andrea; Šegvić, Branimir

    2018-07-01

    The Messinian sequence rocks in the Nile Delta present prolific hydrocarbon reservoirs and are, therefore, of great importance from the aspect of petroleum exploration and development strategies. Yet, little is known about their tectonic provenance and depositional setting. This study focuses on the geochemical signatures archived in the Messinian siliciclastic sediments to employ them as a powerful tool to elucidate the basin evolution during the Messinian salinity crisis (MSC). The pre-MSC Qawasim sediments are texturally and compositionally immature. They are enriched in lithic fragments, foraminiferal bioclasts, and rounded heavy minerals suggesting a significant contribution from the pre-existing Cretaceous-Eocene mixed carbonate-siliciclastic rocks bordering the Nile Delta. In contrast, the textural and mineralogical compositions as well as a range of geochemical proxies (e.g., chemical index of alteration and weathering CIA, CIW as well as index of chemical variability ICV and Zr/Sc ratio) are in favor of prolonged weathering and at least second-cycle origin of the MSC Abu Madi sediments. The mutually correspondent elemental ratios (e.g., Al2O3/TiO2, K2O/Na2O, Zr/Hf, Rb/Sr, Cr/Zr, and Cr/Th) and uniform weathering trends are indicatives for a similar provenance of the pre-MSC Qawasim and MSC Abu Madi sediments. Rare earth element (REE) distribution reveals a significant enrichment in LREE, depletion in HREE, relatively high (La/Yb)N (mean > 9), low (Gd/Yb)N (mean sediments to have been eroded and recycled from the older pre-MSC Qawasim sediments by gravity-flow processes and fluvial channels prior to redeposition as incised-valley-fills during the late stage of the MSC. The geochemical paleoenvironmental indicators such as C-value, Sr/Cu and Sr/Ba confirm arid-dry climatic conditions during the onset of the MSC consistent with the Mediterranean desiccation. These indicators also depict a transition from freshwater to relatively normal salinity conditions

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

    International Nuclear Information System (INIS)

    Arthur, Robson C.J.; Bacchi, Osny O.S.; Reichardt, Klaus; Oliveira, Carloeme Alves de; Correchel, Vladia

    2009-01-01

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

  9. Street-art

    OpenAIRE

    Rybnikářová, Klára

    2009-01-01

    This thesis is concerned with the street-art and graffiti phenomenon. The theoretical research is focused on presenting the essence and character of this art style, while also watching it from socio-cultural point of view and observing it in context of art history. The theoretical study is followed by the didactical part of thesis, where I present possibilities of using the street-art theme in art education programs in the school setting. My thesis is concluded with a discussion of a practica...

  10. Street level society

    DEFF Research Database (Denmark)

    Vinum, Christine; Nissen, Morten

    2006-01-01

    This paper aims to reflect on research findings from different empirical studies of social work with young drug users and socially excluded young people in Copenhagen. In the paper we account for historical changes in social policy and interventions into young people's drug taking in Copenhagen......, and partly from the decentralizing and specializing efforts characteristic of the Danish welfare state and its institutions. We discuss a general turn towards street level interventions to address the problems of social exclusion, as well as different attempts to create what we term street level heterotopias...

  11. Tsunami deposits

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    The NSC (the Nuclear Safety Commission of Japan) demand to survey on tsunami deposits by use of various technical methods (Dec. 2011), because tsunami deposits have useful information on tsunami activity, tsunami source etc. However, there are no guidelines on tsunami deposit survey in JAPAN. In order to prepare the guideline of tsunami deposits survey and evaluation and to develop the method of tsunami source estimation on the basis of tsunami deposits, JNES carried out the following issues; (1) organizing information of paleoseismological record and tsunami deposit by literature research, (2) field survey on tsunami deposit, and (3) designing the analysis code of sediment transport due to tsunami. As to (1), we organize the information gained about tsunami deposits in the database. As to (2), we consolidate methods for surveying and identifying tsunami deposits in the lake based on results of the field survey in Fukui Pref., carried out by JNES. In addition, as to (3), we design the experimental instrument for hydraulic experiment on sediment transport and sedimentation due to tsunamis. These results are reflected in the guideline on the tsunami deposits survey and evaluation. (author)

  12. Tsunami deposits

    International Nuclear Information System (INIS)

    2013-01-01

    The NSC (the Nuclear Safety Commission of Japan) demand to survey on tsunami deposits by use of various technical methods (Dec. 2011), because tsunami deposits have useful information on tsunami activity, tsunami source etc. However, there are no guidelines on tsunami deposit survey in JAPAN. In order to prepare the guideline of tsunami deposits survey and evaluation and to develop the method of tsunami source estimation on the basis of tsunami deposits, JNES carried out the following issues; (1) organizing information of paleoseismological record and tsunami deposit by literature research, (2) field survey on tsunami deposit, and (3) designing the analysis code of sediment transport due to tsunami. As to (1), we organize the information gained about tsunami deposits in the database. As to (2), we consolidate methods for surveying and identifying tsunami deposits in the lake based on results of the field survey in Fukui Pref., carried out by JNES. In addition, as to (3), we design the experimental instrument for hydraulic experiment on sediment transport and sedimentation due to tsunamis. These results are reflected in the guideline on the tsunami deposits survey and evaluation. (author)

  13. History of atmospheric deposition of Cd, Hg, and Pb in North America: Evidence from lake and peat bog sediments

    International Nuclear Information System (INIS)

    Norton, S.A.; Dillon, P.J.; Evans, R.D.; Mierle, G.; Kahl, J.S.

    1990-01-01

    The precipitation chemistry and lake and peat sediment chemistry of three metals emitted to the atmosphere in significant amounts as a result of anthropogenic activity are reviewed. The three metals, Cd, Hg, and Pb, have contrasting source terms, atmospheric residence times, and chemical mobility. Lake and ombrotrophic peat bog sediments record increases in the concentrations and accumulation rates of the metals for most of temperate North America for the last 100 years. These increases are largely related to the burning of coal, smelting of nonferrous metals, the transportation industry, and the industrial production of chlorine. Modern atmospheric fluxes of Cd in central North America are about 1,000 times background fluxes; accumulation rates for Cd in sediments have increased two to 3 times above background, beginning about 100 years ago. Global scale Hg pollution off the atmosphere is suggested by concentrations in northern hemisphere air that are double the Hg content of southern hemisphere air. Accumulation rates of Hg in sediment have approximately doubled in the last 100 years. However, these rates are approximately an order of magnitude less than those for Cd. Modern increases in Pb concentrations are ubiquitous for all lakes examines thus far in North America. Input is from multiple sources and thus the timing of increased accumulation rates in sediment varies across the continent. Typical modern accumulation rates reach maxima at 20 to 30 mg/sq-m/yr, or 100 times that of Cd and 1,000 times that off Hg. Recent decreases in atmospheric lead are reflected in decreases in the accumulation rate of Pb in both lake and peat bog sediment in eastern North America

  14. Street Children and Employment Opportunities

    International Nuclear Information System (INIS)

    Enos, H.N.; Njoka, M.

    1999-01-01

    Although there is a general realization that there are 'people' in the streets, we often take the phenomenon for granted probably because we wake up and go home only to come to the streets the following morning and still find the people. This situation is however changing with the emergence of 'birth' and increase of street children as we begin to take into consideration the category of people to be routinely found on the streets. The phrase 'street children' refer to the children below the statutory adult age living on or found on the streets. These children derive their livelihood from the streets. While the children on the streets may have a 'home' to go to, the latter are an integral part of the street having nowhere to retire to at the end of the day. The street children live in abject poverty and are exposed to many risks. They suffer from malnutrition and deficiency diseases due to low and poor nutrition intake. The street girls get trapped in teenage prostitution quite early in life. Of concern are the issues related to the working street children. Many street children engage in collecting and selling waste paper, bottles and plastics. They are referred to as 'chokora' because of their work of turning garbage upside down as they look for something useful. Unfortunately they have to sell these wastes to powerful forces including people who underpay and harrass them

  15. Partitioning and speciation of trace metal diagenesis in differing depositional environments in the sediments of the Oman margin

    Digital Repository Service at National Institute of Oceanography (India)

    Alagarsamy, R.; Wolff, G.A.; Chester, R.

    , 403 004, India; 2 Oceanography Laboratories, Department of Earth and Ocean Sciences, University of Liverpool, Liverpool L69 3GP, UK. (Received: 5 May 2004; accepted: 28 September 2004) Abstract. Organic-rich sediment samples collected from a transect... were immediately frozen ()20C176C) on board prior to transport to the laboratory where they were freeze-dried and stored at )20C176C prior to analysis. 2.2. METHODOLOGY Particulate Mn and Fe in sediments are distributed between a numbers of host...

  16. Analysis of soft-sediment deformation structures in Neogene fluvio-lacustrine deposits of Çaybağı Formation, Eastern Turkey

    Science.gov (United States)

    Koç Taşgin, Calibe; Türkmen, İbrahim

    2009-06-01

    During the Neogene, both strike-slip and extensional regimes coexisted in eastern Turkey and, a number of fault-bounded basins associated with the East Anatolian Fault System developed. The Çaybağı Formation (Late Miocene-Early Pliocene) deposited in one of these basins consists of fluvio-lacustrine deposits. Numerous soft-sediment deformation structures are encountered in this formation, particularly in conglomerates, medium- to coarse-grained tuffaceous sandstones and claystones: folded structures (slumps, convolute laminations, and simple recumbent folds), water-escape structures (intruded sands, internal cusps, interpenetrative cusps and sand volcanoes), and load structures (load casts, pseudonodules, flame structures, and pillow structures). These structures are produced by liquefaction and/or fluidization of the unconsolidated sediments during a seismic shock. Consequently, the existence of seismically-induced deformation structures in the Çaybağı Formation and the association with a Neogene intraformational unconformity, growth faults, and reverse faults in the Çaybağı basin attest to the tectonic activity in this area during the Late Miocene and Early Pliocene. The East Anatolian Fault System, in particular the Uluova fault zone, is the most probable seismogenic source. Earthquakes with a magnitude of over 5 in the Richter scale can be postulated.

  17. The City Street

    NARCIS (Netherlands)

    H.C. van der Wouden

    1999-01-01

    Original title: De stad op straat. The city street; the public space in perspective (De stad op straat; de openbare ruimte in perspectief) by the Netherlands Institute for Social Research/SCP is intended to contribute to the formation of new ideas about the public space and the future of

  18. Occupy Wall Street

    DEFF Research Database (Denmark)

    Jensen, Michael J.; Bang, Henrik

    2013-01-01

    This article analyzes the political form of Occupy Wall Street on Twitter. Drawing on evidence contained within the profiles of over 50,000 Twitter users, political identities of participants are characterized using natural language processing. The results find evidence of a traditional...

  19. Saving Mango Street

    Science.gov (United States)

    Van Winkle, Katie

    2012-01-01

    The author first learned about cultural diversity and racial justice in Mr. Sanderson's middle school English class. They read a book called "The House on Mango Street" by Sandra Cisneros and learned about a different culture, but also about a community with striking similarities to their own. The main character in the novel, Esperanza,…

  20. Deposits of Large-scale Mass Movements in the Sediments of Hallstätter See (Austria) - Recurrent Natural Hazards at a UNESCO World Cultural Heritage Site

    Science.gov (United States)

    Lauterbach, S.; Strasser, M.; Tjallingii, R.; Kowarik, K.; Reschreiter, H.; Spatl, C.; Brauer, A.

    2017-12-01

    The cultural importance of underground salt mining in Hallstatt (Austria), which is documented since the Middle Bronze Age, has been recognized already 20 years ago by assigning the status of a UNESCO World Cultural Heritage Site to the Hallstatt area, particularly because of the wealth of archaeological artefacts from the Early Iron Age. Local mining activity is well documented for prehistoric times and known to have been repeatedly affected by large-scale mass movements, for example at the end of the Bronze Age and during the Late Iron Age. In contrast, evidence of mining activity between the 5th and late 13th century AD is scarce, which could be related to socio-economic changes but also to continued mass movement activity, possibly biasing the archaeological record. Within the present study, a 15.63-m-long 14C-dated sediment core from Hallstätter See has been investigated with respect to the deposits of large-scale mass movements. Most of the lake sediment sequence consists of cm- to sub-mm-scale laminated carbonate mud with frequently intercalated small-scale turbidites, reflecting seasonally variable detrital input from the tributaries, but two major event layers clearly stand out. The upper one comprises a 2.45-m-thick basal mass transport deposit (containing folded laminated sediments, homogenized sediments with liquefaction structures, and coarse gravel) and an overlying 1.45-m-thick co-genetic turbidite. From the lower event layer only the topmost part of the turbiditic sequence with a (minimum) thickness of 1.49 m was recovered. Based on their sedimentological characteristics, both event layers are interpreted as the subaqueous continuation of large-scale mass movements, which occurred at ca. 1050 and 2300 cal. years BP and possibly originated from the rock walls along the western lake shore where also the salt mining area is located. This indicates that mass movement activity not only threatened prehistoric salt mining, but occurred also repeatedly

  1. Spatial and Temporal Variability of Dust Deposition in the San Juan Mountains, CO: A Network of Late Holocene Lake Sediment Records

    Science.gov (United States)

    Arcusa, S.; Routson, C.; McKay, N.

    2017-12-01

    Millions of stakeholders living in the arid southwestern US rely on snowmelt from the San Juan Mountains of Colorado. However, dust deposition on snow accelerates snowmelt, challenging water management. Dustiness in the southwestern US is primarily mediated by drought, which is projected to increase in frequency and severity. Over the past several millennia, multidecadal-length megadroughts are hypothesized to have enhanced regional dustiness. These past megadroughts were more frequent during the Roman (ca. 1-400 CE) and Medieval (ca. 800-1300 CE) time periods and were similar in duration and severity to those projected for the future. Developing an understanding of the temporal and spatial patterns of past dust deposition in the San Juan Mountains will help inform adaptation strategies for future droughts. A network of short sediment cores from six alpine lakes in the San Juan Mountains were collected in 2016 and 2017 to investigate the spatial patterns of dust deposition. The range in lake basin characteristics in the network, such as catchment size, helps to constrain the influence of secondary dust deposition. Grain size analysis and X-ray Fluorescence were combined with radiocarbon dating to trace the temporal patterns in dust flux over the Late Holocene (the last 2000 years). The End-member Modelling Algorithm (EMMA) was used to estimate the dust proportion in the lake sediment, distinguishing from locally derived catchment material. Comparisons to modern dust-on-snow samples were made to identify the dust size distribution. The results show that deposition trends were not uniform between the south-eastern and north-western San Juans, with increasing trends towards the present in the former, possibly reflecting a shift in dust sources associated with changes in wind speed and direction. Dust levels greater than long term averages were recorded during the Medieval and Roman periods. The network also showed the influence of lake basin parameters, such as the

  2. Lake-sediment record of PAH, mercury, and fly-ash particle deposition near coal-fired power plants in Central Alberta, Canada.

    Science.gov (United States)

    Barst, Benjamin D; Ahad, Jason M E; Rose, Neil L; Jautzy, Josué J; Drevnick, Paul E; Gammon, Paul R; Sanei, Hamed; Savard, Martine M

    2017-12-01

    We report a historical record of atmospheric deposition in dated sediment cores from Hasse Lake, ideally located near both currently and previously operational coal-fired power plants in Central Alberta, Canada. Accumulation rates of spheroidal carbonaceous particles (SCPs), an unambiguous marker of high-temperature fossil-fuel combustion, in the early part of the sediment record (pre-1955) compared well with historical emissions from one of North America's earliest coal-fired power plants (Rossdale) located ∼43 km to the east in the city of Edmonton. Accumulation rates in the latter part of the record (post-1955) suggested inputs from the Wabamun region's plants situated ∼17-25 km to the west. Increasing accumulation rates of SCPs, polycyclic aromatic hydrocarbons (PAHs) and Hg coincided with the previously documented period of peak pollution in the Wabamun region during the late 1960s to early 1970s, although Hg deposition trends were also similar to those found in western North American lakes not directly affected by point sources. A noticeable reduction in contaminant inputs during the 1970s is attributed in part to technological improvements and stricter emission controls. The over one hundred-year historical record of coal-fired power plant emissions documented in Hasse Lake sediments has provided insight into the impact that both environmental regulations and changes in electricity output have had over time. This information is crucial to assessing the current and future role of coal in the world's energy supply. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  3. Street Lines, US, 2015, NAVTEQ

    Data.gov (United States)

    U.S. Environmental Protection Agency — NAVTEQ Streets for the United States. The Streets layer contains all roads plus all Road Network attributes such as direction of travel, lanes, dividers, speed...

  4. Wall Street som kreationistisk forkynder

    DEFF Research Database (Denmark)

    Ekman, Susanne

    2016-01-01

    Artiklen gennemgår Karen Hos etnografi om Wall Street: "Liquidated: An ethnography of Wall Street" set i lyset af den offentlige debat vedrørende Goldman Sachs opkøb af Dong......Artiklen gennemgår Karen Hos etnografi om Wall Street: "Liquidated: An ethnography of Wall Street" set i lyset af den offentlige debat vedrørende Goldman Sachs opkøb af Dong...

  5. Early diagenesis in the sediments of the Congo deep-sea fan dominated by massive terrigenous deposits: Part II - Iron-sulfur coupling

    Science.gov (United States)

    Taillefert, Martial; Beckler, Jordon S.; Cathalot, Cécile; Michalopoulos, Panagiotis; Corvaisier, Rudolph; Kiriazis, Nicole; Caprais, Jean-Claude; Pastor, Lucie; Rabouille, Christophe

    2017-08-01

    Deep-sea fans are well known depot centers for organic carbon that should promote sulfate reduction. At the same time, the high rates of deposition of unconsolidated metal oxides from terrigenous origin may also promote metal-reducing microbial activity. To investigate the eventual coupling between the iron and sulfur cycles in these environments, shallow sediment cores (Congo River deep-sea fan ( 5000 m) were profiled using a combination of geochemical methods. Interestingly, metal reduction dominated suboxic carbon remineralization processes in most of these sediments, while dissolved sulfide was absent. In some 'hotspot' patches, however, sulfate reduction produced large sulfide concentrations which supported chemosynthetic-based benthic megafauna. These environments were characterized by sharp geochemical boundaries compared to the iron-rich background environment, suggesting that FeS precipitation efficiently titrated iron and sulfide from the pore waters. A companion study demonstrated that methanogenesis was active in the deep sediment layers of these patchy ecosystems, suggesting that sulfate reduction was promoted by alternative anaerobic processes. These highly reduced habitats could be fueled by discrete, excess inputs of highly labile natural organic matter from Congo River turbidites or by exhumation of buried sulfide during channel flank erosion and slumping. Sulfidic conditions may be maintained by the mineralization of decomposition products from local benthic macrofauna or bacterial symbionts or by the production of more crystalline Fe(III) oxide phases that are less thermodynamically favorable than sulfate reduction in these bioturbated sediments. Overall, the iron and sulfur biogeochemical cycling in this environment is unique and much more similar to a coastal ecosystem than a deep-sea environment.

  6. Depositional environment and sedimentary of the basinal sediments in the Eibiswalder Bucht (Radl Formation and Lower Eibiswald Beds), Miocene Western Styrian Basin, Austria

    Science.gov (United States)

    Stingl, K.

    1994-12-01

    The Eibiswald Bucht is a small subbasin of the Western Styrian Basin exposing sediments of Lower Miocene age. In the past the entire sequence exposed in the Eibiswalder Bucht has been interpreted as being of fluvial/lacustrine origin; here, results are presented of detailed sedimentological investigations that lead to a revision of this concept. The lowermost siliciclastic sedimentary unit of the Eibiswalder Bucht sequence is the Radl Formation. It is overlain by the Eibiswald Beds, which are subdivided into the Lower, Middle and Upper Eibiswald Beds. The Radl Formation and the Lower Eibiswald Beds are interpreted as a fan delta complex deposited along NNW-SSE striking faults. Based on the sedimentary facies this fan delta can be subdivided into a subaerial alluvial fan facies group, a proximal delta facies group and a distal delta/prodelta facies group. The Radl Formation comprises the alluvial fan and proximal delta facies groups, the Lower Eibiswald Beds the distal delta/prodelta facies group. The alluvial fan and the proximal delta consist of diverse deposits of gravelly flows. The distal delta/prodelta consists of wave-reworked, bioturbated, low density turbidites intercalated with minor gravelly mass flows. The prodelta can be regarded as as the basin facies of the small and shallow Eibiswalder Bucht, where marine conditions prevailed. The basin was probably in part connected with the Eastern Styrian Basin, the contemporary depositional environment of the Styrian Schlier (mainly turbiditic marine offshore sediments in the Eastern Styrian Basin). Analysis of the clast composition, in conjunction with the paleotransport direction of the coarse delta mass flows of the Radl Formation, shows that the source rocks were exclusively crystalline rocks ranging from greenschists to eclogites.

  7. The roles of physical mixing and biochemical composition on the depositional characteristics of flocculated suspended sediment in the Eden estuary, Scotland

    Science.gov (United States)

    Hope, Julie; Manning, Andrew; Aspden, Rebecca; Baas, Jaco; Paterson, David

    2015-04-01

    Sediment load in estuarine waters is generally composed of a mixture of sand, clay and biological matter and it is recognised that there is strong mediation of the physical behaviour of flocs by biological components of the system. Extracellular polymeric substances (EPS) secreted by benthic and pelagic bacteria and algae are a key variable influencing flocculation processes. Variation in the nature and concentration of polymers can alter sediment stability and transport in mixed sediment beds but these substances can also significantly enhance inter-particle cohesion in the water column and therefore deposition and transport. This study examined the variation in naturally occurring EPS concentration and its influence on several physical variables of flocs within the Eden Estuary, Scotland. Samples were collected for total suspended sediment and colormetric analysis of polymer concentration. Subsamples were transferred to the settling column of the LabSFLOC-2 - Laboratory Spectral Flocculation Characteristics -high resolution video floc camera system (Manning, 2006) where settling flocs were viewed (resolution~10μm) to determine floc size (D) and settling velocity (Ws) characteristics. Preliminary results indicate a wide range of microfloc (D160mm) fractions present, with the latter approaching 1 mm during flocculation conducive conditions. Correspondingly, when considering all floc samples, floc settling velocities generally spanned three orders of magnitude with floc size and settling velocities correlating with polymer concentrations. These typically ranged from slow settling (Ws of 0.01-0.05 mm.s-1) predominantly organically based microflocs to faster settling, significantly larger and more porous Macroflocs settling at ~10-15 mm.s-1. The temporal distributions of D and Ws, sediment and polymer concentrations, and the sugar composition of the polymers in suspension are examined in the paper with variation also related to physical and microbiological factors in

  8. Use of reservoir deposits to reconstruct the recent changes in sediment yields from a small granite catchment in the Yimeng Mountain region, China

    Science.gov (United States)

    Zhang, Yunqi; Long, Yi; Li, Bao; Xu, Shujian; Wang, Xiaoli; Liao, Jia

    2017-09-01

    Information on recent changes in sediment yields from small catchments provides a better understanding of temporal trends in soil loss from certain physical and human-influenced landscapes that have been subjected to recent environmental changes, and will help bridge the current knowledge gap that exists between hillslope erosion and sediment transport in rivers. The Yimeng Mountain region, characterized by alternating granite and limestone, is one of the most susceptible regions to soil erosion in northern China, and has been subjected to intensive anthropogenic activity in recent years. Soil loss from areas underlain by granite is particularly obvious, and is the main sediment source for the Yihe River. In this study, we used reservoir deposits to estimate the changes in sediment yields over the past 50 years from a small catchment underlain by granite, namely the Jiangzhuang catchment in the Yimeng Mountain region. Three cores were collected from the Jiangzhuang Reservoir in the catchment. The activities of 137Cs and 210Pbex at different depths, clay (grain size reference to human activity and environmental change in the catchment. The chronologies of the cores were established by 137Cs and 210Pbex dating. The area-specific sediment yield (SSY) for different time periods since dam construction was estimated from each core by referring to the original capacity curve of the reservoir. The results indicate that the depth profiles of 137Cs, 210Pbex, clay, and SOC contents in cores from the Jiangzhuang Reservoir reflect the general history of human disturbances on the catchment over the past 50 years. The estimated SSY value from each core for each period ranged from 7.2 ± 2.7 to 23.7 ± 8.3 t ha- 1 y- 1, with a mean of 12.5 ± 4.6 t ha- 1 y- 1. SSY decreased during 1954-1972, and then showed a general tendency to increase. The temporal pattern of the sediment yield largely reflects the history of environmental change influenced by human activity in the catchment.

  9. Factors controlling present-day tufa dynamics in the Monasterio de Piedra Natural Park (Iberian Range, Spain): depositional environmental settings, sedimentation rates and hydrochemistry

    Science.gov (United States)

    Vázquez-Urbez, M.; Arenas, C.; Sancho, C.; Osácar, C.; Auqué, L.; Pardo, G.

    2010-07-01

    The tufa record and hydrochemical characteristics of the River Piedra in the Monasterio de Piedra Natural Park (NE Spain) were studied for 6 years. The mean discharge of this river was 1.22 m3/s. The water was supersaturated with calcium carbonate. The HCO3 -, Ca2+ and TDIC concentrations decreased along the 0.5-km-long studied stretch, whereas the calcite SI showed no systematic downstream or seasonal variation over the same stretch. Several sedimentary subenvironments exist in which four broad types of tufa facies form: (1) Dense laminated tufa (stromatolites), (2) Dense to porous, massive tufa, (3) Porous, coarsely laminated tufa with bryophytes and algae, and (4) Dense, hard, laminated deposits in caves. The half-yearly period thickness and weight of sediment accumulated on 14 tablets installed in several subenvironments showed that the deposition rate was greater in fast flowing river areas and in stepped waterfalls, and lower in slow flowing or standing river areas and in spray and splash areas. Mechanical CO2 outgassing is the main factor controlling calcite precipitation on the river bed and in waterfalls, but this process does not explain the seasonal changes in depositional rates. The deposition rates showed a half-yearly period pattern recorded in all fluvial subenvironments persistent over time (5.26 mm, 0.86 g/cm2 in warm periods; 2.26 mm, 0.13 g/cm2 in cool periods). Mass balance calculations showed higher calcite mass values in warm (21.58 mg/L) than in cool (13.68 mg/L) periods. This biannual variation is mainly attributed to the seasonal differences in temperature that caused changes in inorganic calcite precipitation rate and in biomass and the correlative photosynthetic activity. Tufa sedimentation was therefore controlled by both physicochemical and biological processes. The results of this study may help test depositional rates and their environmental controls and thus assess the climatic and hydrological significance of ancient tufas in semi

  10. The origin of dose distributions in fluvial sediments, and the prospect of dating single grains from fluvial deposits using optically stimulated luminescence

    International Nuclear Information System (INIS)

    Olley, J.M.; Caitcheon, G.G.; Roberts, R.G.

    1999-01-01

    We examine the causes of the asymmetric distributions of dose observed from measurements of the optically stimulated luminescence emitted by small aliquots of fluvial quartz, and deduce that the asymmetry arises as a result of samples being composed of a mix of mainly well bleached grains with grains that were effectively unbleached at the time of deposition. We demonstrate that the shapes of the dose distributions can be used to assess the likelihood that aliquots consist only of grains that were well-bleached at the time of deposition. The more asymmetric the distribution, the greater the probability that the aliquots with the lowest dose most closely represent the true burial dose. Single grains with differing doses are present in each of the samples examined, and the population with the lowest dose gives an optical age consistent with the expected burial age. This result implies that the beta-dose heterogeneity in these deposits is small, and that the effects of micro-dosimetric variations on optical dating of individual grains are not significant for these samples. We demonstrate that single-grain dating of fluvial material is possible and practicable using standard Risoe optical dating equipment, and we conclude that application of a new regenerative-dose protocol to single grains of quartz, using the lowest dose population to estimate the burial dose, is the best available means of obtaining reliable luminescence ages for heterogeneously bleached fluvial sediments

  11. Stylolites, porosity, depositional texture, and silicates in chalk facies sediments:Ontong Java Plateau - Gorm and Tyra fields, North Sea

    OpenAIRE

    Fabricius, Ida Lykke; Borre, Mai K.

    2007-01-01

    Comparison of chalk on the Ontong Java Plateau and chalk in the Central North Sea indicates that, whereas pressure dissolution is controlled by effective burial stress, pore-filling cementation is controlled by temperature. Effective burial stress is caused by the weight of all overlying water and sediments as counteracted by the pressure in the pore fluid, so the regional overpressure in the Central North Sea is one reason why the two localities have different relationships between temperatu...

  12. Smart street lighting management

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuti, S.; Annunziato, M. [Energy New Technologies and Sustainable Economic Development Agency ENEA, Rome (Italy); Moretti, F. [Automation and Computer Science Department, University & #x27; Roma Tre& #x27; , Rome (Italy)

    2013-08-15

    In this work, we propose a new street lighting energy management system in order to reduce energy consumption. The key idea we want to accomplish is that of 'energy on demand' meaning that energy, in this case light, is provided only when needed. In order to achieve this goal, it is critical to have a reliable demand model, which in the case of street lighting turns out to be a traffic flow rate forecasting model. In order to achieve this goal, several methods on the 1-h prediction have been compared and the one providing the best results is based on artificial neural networks. Moreover, several control strategies have been tested and the one which gave the best energy savings is the adaptive one we carried out. Experimentation has been carried out on real data and the study shows that with the proposed approach, it is possible to save up to 50 % of energy compared to no regulation systems.

  13. Post-depositional reactivity of the plutonium in different sediment facies from the English channel - an experimental approach

    International Nuclear Information System (INIS)

    Gouzy, A.; Boust, D.; Klein, A.

    2004-01-01

    The plutonium discharged into sea (in particular resulting from the activity of the reprocessing plants of nuclear fuels) presents a great affinity for the sedimentary particles. In the English Channel, the weakness of the plutonium concentrations met in the natural environment makes very difficult a direct study of the diagenetic phenomena which influences on the behavior of this radionuclide after its incorporation to the sedimentary column. On the scale of the all English Channel, the stock of plutonium immobilized in the sediments is significant (some TBq), this fact justifies the study of its becoming. With this intention, we constructed a set of experiments on series marine sediments with various sedimentological facies, which have been spiked with plutonium. After a one-month incubation period, various parameters describing the behavior of plutonium were given: (1) distribution of plutonium between the particulate phases and the pore waters; (2) quantification of plutonium associated with reactive sulphides; (3) distribution of plutonium between the particles and the seawater during a sediment resuspension episode. (author)

  14. The dirt on sediments

    Science.gov (United States)

    Smith, Loren M.; Euliss, Ned H. "Chip"

    2010-01-01

    In the wetland science field, sediment deposition is often thought of as being beneficial especially when one thinks of coastal estuarine systems. For example, sediments deposited from streams and rivers are necessary to naturally build and maintain tidal marshes. These sediments come from eroded upland soils in the interior of the continent. When these sediments are diverted from natural coastal deposition areas, such as occurs from river channelization, we lose marshes through subsidence as is happening throughout coastal Louisiana. However, the value of eroded soils is all a matter of hydrogeomorphic perspective.

  15. Bedform reconstruction using Terrestrial Laser Scanning at Hunt's Hole, New Mexico: implications for sediment transport in pyroclastic surge deposits and criteria for their identification on Mars

    Science.gov (United States)

    Edgar, L.; Grotzinger, J. P.; Ewing, R. C.; Southard, J. B.; Lamb, M. P.

    2011-12-01

    Pyroclastic surges are dilute flows of gas and rock fragments, typically generated by the interaction of magma and water. Due to their hazardous nature, very little is known about sediment transport during these eruptions. However, the cross-stratified deposits that they leave behind provide an important record of flow conditions, if properly interpreted. In the absence of geologic context (and volcanic indicators such as bombs and lapilli), it may be difficult to distinguish bedforms in pyroclastic surge deposits from those in eolian or fluvial deposits. There has been some debate about the identification of pyroclastic surge deposits on Mars, suggesting a need to establish better criteria for recognizing these deposits in remote sensing applications. The goals of this study are to use physical characteristics to better understand bedform kinematics and gain insight into the flow dynamics of pyroclastic surges, and to establish criteria to distinguish pyroclastic surges from other depositional environments on Mars. Two examples of pyroclastic surge deposits are exposed in Hunt's Hole (HH) and Kilbourne Hole in southern NM. These volcanic craters expose up to 13 m of stratigraphy, dominated by dm-to-m-scale bedforms. The geomorphic pattern around the rim of HH provides 3D exposures at the scale of the bedforms, which enables observations of bedform geometries. We identify several facies, and measure bedform characteristics in the cross-stratified facies. Bedforms range in height from 25-80 cm, and wavelength from 190-460 cm. Stoss slope angles range from 4-11°, and lee slope from 2-18°. Geometries indicate possible bedform merging, as smaller bedforms overtake others to build larger features. Bedform interactions have been described in modern eolian systems, typically in plan-view, but these surge deposits may provide an opportunity to observe them in outcrop in cross-section. We propose that bedforms in pyroclastic surges can be identified by a unique style of

  16. Geochemistry of Mine Waste and Mill Tailings, Meadow Deposits, Streambed Sediment, and General Hydrology and Water Quality for the Frohner Meadows Area, Upper Lump Gulch, Jefferson County, Montana

    Science.gov (United States)

    Klein, Terry L.; Cannon, Michael R.; Fey, David L.

    2004-01-01

    Frohner Meadows, an area of low-topographic gradient subalpine ponds and wetlands in glaciated terrane near the headwaters of Lump Gulch (a tributary of Prickly Pear Creek), is located about 15 miles west of the town of Clancy, Montana, in the Helena National Forest. Mining and ore treatment of lead-zinc-silver veins in granitic rocks of the Boulder batholith over the last 120 years from two sites (Frohner mine and the Nellie Grant mine) has resulted in accumulations of mine waste and mill tailings that have been distributed downslope and downstream by anthropogenic and natural processes. This report presents the results of an investigation of the geochemistry of the wetlands, streams, and unconsolidated-sediment deposits and the hydrology, hydrogeology, and water quality of the area affected by these sources of ore-related metals. Ground water sampled from most shallow wells in the meadow system contained high concentrations of arsenic, exceeding the Montana numeric water-quality standard for human health. Transport of cadmium and zinc in ground water is indicated at one site near Nellie Grant Creek based on water-quality data from one well near the creek. Mill tailings deposited in upper Frohner Meadow contribute large arsenic loads to Frohner Meadows Creek; Nellie Grant Creek contributes large arsenic, cadmium, and zinc loads to upper Frohner Meadows. Concentrations of total-recoverable cadmium, copper, lead, and zinc in most surface-water sites downstream from the Nellie Grant mine area exceeded Montana aquatic-life standards. Nearly all samples of surface water and ground water had neutral to slightly alkaline pH values. Concentrations of arsenic, cadmium, lead, and zinc in streambed sediment in the entire meadow below the mine waste and mill tailings accumulations are highly enriched relative to regional watershed-background concentrations and exceed consensus-based, probable-effects concentrations for streambed sediment at most sites. Cadmium, copper, and

  17. Growth of superconducting Bi2Sr2CaCu2O8+δ films by sedimentation deposition and liquid phase sintering and annealing technique

    International Nuclear Information System (INIS)

    Manahan, R.L.C.; Sarmago, R.V.

    2006-01-01

    We report on a technique of growing highly c-axis oriented Bi 2 Sr 2 CaCu 2 O 8+δ (Bi-2212) thick films on MgO substrate using a combined sedimentation-deposition and liquid phase sintering and annealing process. The temperature profiles employed partial melting followed by rapid cooling to temperature below the melting point. Scanning electron micrographs show that the films have a smooth surface. No evidence of grain boundaries on the film's surface can be seen. The critical temperatures of the samples range from ∼67 K to ∼81 K. This method presents a quick and easy preparation for high quality epitaxial Bi-2212 films

  18. Geochemical Indicators of the Carbonate Sedimentation Depositional Environments and Geodynamic Conditions in the East of the Middle Urals in the Kizelovian Time

    Directory of Open Access Journals (Sweden)

    S. A. Dub

    2017-12-01

    Full Text Available Geochemical characteristics of the limestones of Kizelovskian substage of the Eastern Urals zone (Rezh River, Middle Urals, such as carbon and oxygen isotopic composition, concentration of minor and trace elements, and redox value indicators, were studied in details. Based on the results of data interpretation and analysis of lithological features, it was assumed that carbonate deposits formed in shallow oxygen-rich environment with high bioproductivity warm water ecosystem, and within the isolated carbonate platform with a steady sinking territory. Some signs indicate that sedimentation during the Kizelovian time occurred in the inner lagoon of a large atoll. The Maldivian archipelago could be a contemporary analogue of the Rezhevskaya carbonate platform.

  19. Grain size distribution of road-deposited sediment and its contribution to heavy metal pollution in urban runoff in Beijing, China.

    Science.gov (United States)

    Zhao, Hongtao; Li, Xuyong; Wang, Xiaomei; Tian, Di

    2010-11-15

    Pollutant washoff from road-deposited sediment (RDS) is an increasing problem associated with the rapid urbanization of China that results in urban non-point source pollution. Here, we analyzed the RDS grain size distribution and its potential impact on heavy metal pollution in urban runoff from impervious surfaces of urban villages, colleges and residences, and main traffic roads in the Haidian District, Beijing, China. RDS with smaller grain size had a higher metal concentration. Specifically, particles with the smallest grain size (runoff water accounted for greater than 70% of the metal mass in the total suspended solids (TSS). The heavy metal content in the TSS was 2.21-6.52% of that in the RDS. These findings will facilitate our understanding of the importance of RDS grain size distribution in heavy metal pollution caused by urban storm runoff. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Street as Public Space - Measuring Street Life of Kuala Lumpur

    Science.gov (United States)

    Sulaiman, Normah; Ayu Abdullah, Yusfida; Hamdan, Hazlina

    2017-10-01

    Kuala Lumpur has envisioning in becoming World Class City by the year 2020. Essential elements of form and function of the urban environment are streets. Streets showcase the community and connect people. It’s one of the most comfortable social environment that provides aesthetical and interaction pleasure for everyone. Classified as main shopping streets in the local Kuala Lumpur urban design guidelines, Jalan Masjid India (JMI) has its uniqueness of shopping experience and social interaction. This conceptual paper will study the physical and cultural characteristics of the street that will generate the street character by mapping its original characters. The findings will focus on strengthening the methodology applied to promote improvements in evaluating it as a great public space. Results will also contribute to understanding the overall site context, the street connectivity, and urban dynamics. This paper is part of a larger study that addresses on transforming the sociability of public space.

  1. Soft-sediment deformation structures interpreted as seismites in the uppermost Aptian to lowermost Albian transgressive deposits of the Chihuahua basin (Mexico)

    Science.gov (United States)

    Blanc, E.J.-P.; Blanc-Aletru, M. -C.; Mojon, P.-O.

    1998-01-01

    Several levels of soft-sediment deformation structures (s.-s.d.s.) cut by synsedimentary normal faults have been observed in the transition beds between the "Las Vigas" and "La Virgen" formations (Cretaceous) in the northeastern part of the Chihuahua basin in Mexico. These structures consisted of four kinds of motifs (floating breccias, flame-like structures, large pillow structures, and wavy structures). They are restricted to five "stratigraphie" levels (Z1-Z5) and surrounded by undeformed beds in fluvio-lacustrine and tidal deposits and can be traced over a distance of several hundred meters. This deformation is interpreted to have resulted from the combined effects of liquidization and shear stress in soft-sediments due to local earthquakes in the area which could have been generated during the rifting stage of the Chihuahua basin. New constraints placed on the age of the "Las Vigas" Formation (bracketed by Late Aptian charophytes at the bottom and colomiellids of late Aptian to earliest Albian age at the top) suggest that this synrift tectonism lasted at least until the end of the Aptian. ?? Springer-Verlag 1998.

  2. How depositional conditions control input, composition, and degradation of organic matter in sediments from the Chilean coastal upwelling region

    DEFF Research Database (Denmark)

    Niggemann, Jutta; Ferdelman, Timothy G.; Lomstein, Bente Aagaard

    2007-01-01

    investigated for excess 210Pb (210Pbxs) activity, total organic and total inorganic carbon concentrations (TOC and TIC, respectively), C/N-ratios, organic carbon isotopic compositions (d13C), chlorin concentrations, Chlorin Indices (CI), and sulfate reduction rates (SRR). Sediment accumulation rates obtained...... m‑2 d‑1), which was partly due to the greater water depth of most of the sediments investigated in the northern region and consistent with a lower quality of the sedimentary OM at 23°S. Reaction rate constants for TOC degradation that were obtained from measured SRR (kSRR; 0.0004‑0.0022 yr‑1) showed...... a good correspondence to kTOC that were derived from the depth profiles of TOC (0.0003‑0.0014 yr‑1). Both, kSRR and kTOC, reflect differences in OM composition. At 36°S they were related to the degradation state of bulk OM (represented by C/N-ratios), whereas near 23°S they were related to the freshness...

  3. Zn speciation in a soil contaminated by the deposition of a dredged sediment by synchrotron X-ray techniques

    International Nuclear Information System (INIS)

    Isaure, Marie-Pierre; Manceau, Alain; Laboudigue, Agnes; Tamura, Nobumichi; Marcus, Matthew A.

    2003-09-01

    The nature and proportion of Zn species present in an agricultural soil overlaid by a dredged contaminated sediment have been untangled by the novel combination of three non-invasive synchrotron-based x-ray techniques: x-ray microfluorescence (μSXRF), microdiffraction (μXRD), and absorption spectroscopy (EXAFS). One primary (franklinite) and two secondary (phyllomanganate and phyllosilicate) Zn-containing minerals were identified in the initial soil, and another primary (ZnS) and a new secondary (Fe-(oxyhydr)oxide) Zn species in the covered soil. The quantitative analysis of EXAFS spectra recorded on bulk samples indicated that ZnS and Zn-Fe (oxyhydr)oxides amounted to 71+-10 percent and 27+-10 percent, respectively, and the other Zn species to less than 10 percent. The two new Zn species found in the covered soil result from the gravitational migration of ZnS particles initially present in the sediment, and from their further oxidative dissolution and fixation of leached Zn on F e (oxyhydr) oxides

  4. Slumping and a sandbar deposit at the Cretaceous-Tertiary boundary in the El Tecolote section (northeastern Mexico): An impact-induced sediment gravity flow

    Science.gov (United States)

    Soria, Ana R.; Liesa, Carlos L.; Mata, Maria Pilar; Arz, José A.; Alegret, Laia; Arenillas, Ignacio; Meléndez, Alfonso

    2001-03-01

    Slumps affecting uppermost Méndez Formation marls, as well as the spherulitic layer and basal part of the sandy deposits of the Cretaceous-Tertiary (K-T) boundary clastic unit, are described at the new K-T El Tecolote section (northeastern Mexico). These K-T clastic deposits represent sedimentation at middle-bathyal water depths in channel and nonchannel or levee areas of reworked materials coming from environments ranging from outer shelf to shallower slope via a unidirectional, high- to low-density turbidite flow. We emphasize the development and accretion of a lateral bar in a channel area from a surging low-density turbidity current and under a high-flow regime. The slumps discovered on land and the sedimentary processes of the K-T clastic unit reflect destabilization and collapse of the continental margin, support the mechanism of gravity flows in the deep sea, and represent important and extensive evidence for the impact effects in the Gulf of México triggered by the Chicxulub event.

  5. Sediment transport and deposition during extreme sea storm events at the Salerno Bay (Tyrrhenian Sea: comparison of field data with numerical model results

    Directory of Open Access Journals (Sweden)

    F. Budillon

    2006-01-01

    Full Text Available Seismic stratigraphy and core litho-stratigraphy in the Salerno Bay inner shelf (Southern Tyrrhenian Sea reveal significant storm deposition episodes over the last 1 ky. Three major events are preserved as decimetre thick silt/sand layers bounded at their base by erosional surfaces and sealed in the muddy marine sequences between 25 and 60 m of depth. Geochronology and chrono-stratigraphy on core sediment point towards a recurrence of major sea storms between 0.1 and 0.3 ky and put the last significant event in the 19th century, when no local meteorological time series is available. A modelling of extreme sea-storms with a return period of about 0.1 ky is here proposed based on historical hindcast and aims at explaining the occurrence of such unusual deep and thick sand deposits in the northern sector of the bay. Results highlight the vulnerability of the northern coast of the Salerno Bay to the south western sea storms which can drive waves up to about 8 m high and wave period of about 13 s. With these conditions an intense combined flow current is formed and might account for winnowing fine sand down to the depth of 40 m at least. The numerical model thus confirms a possible sand transport in the bottom boundary layer due to wave-current interaction and could corroborate the interpretation of the most recent sand layers, included in the cores, as being generated under extreme sea storm conditions.

  6. Bioaccumulation, toxicokinetics, and effects of copper from sediment spiked with aqueous Cu, nano-CuO, or micro-CuO in the deposit-feeding snail, Potamopyrgus antipodarum

    DEFF Research Database (Denmark)

    Pang, Chengfang; Selck, Henriette; Banta, Gary Thomas

    2013-01-01

    The present study examined the relative importance of copper (aqueous Cu and CuO particles of different sizes) added to sediment to determine the bioaccumulation, toxicokinetics, and effects in the deposit feeder Potamopyrgus antipodarum. In experiment 1, the bioaccumulation of Cu (240 mg Cu/g dr...

  7. Using tracer-based sediment budgets to quantify erosion and deposition within harvested forests in south-east NSW, Australia

    International Nuclear Information System (INIS)

    Wallbrink, P.J.; Roddy, B.P.; Olley, J.M.

    1998-01-01

    Full text: The total impact of forest operations on the store of soil material within harvested coupes can be difficult to quantify. A study was recently undertaken in a small (∼12 ha) basin near Bombala, south-east NSW to measure both the net amount of soil erosion from the basin, and the redistribution of eroded soils and sediments within it. The dry sclerophyll study area was divided into several distinct elements: log landings, snig tacks, general harvest area (GHA), cross banks, and the filter strip of native vegetation left adjacent to the major streamline Measurements of two radionuclide tracers ( 137 Cs and 210 Pb-excess) in each of these locations were then integrated into budgets describing the movement of soil within and between the various landscape elements. The 137 Cs budget showed that no net loss of soil material had occurred from within the study area, with retention of 109 ± 14 %. Conversely, the 210 Pb-excess budget showed a total retention of 78 ± 12 %. The deficit of 2 10 Pb compared to that of 137 Cs was explained by a combination of analytical and sampling uncertainties, losses of 2 10 Pb associated with combustion and/or transport of litter and organic matter from the site, and some small loss of surface soil (to a depth of 2 mm). However, no evidence of surface-derived topsoil material was found in sediments currently being transported from the site. Both tracer budgets showed that a net loss of soil from the snig tracks and log landings had occurred. This was quantified to be 28 ± 13 mm and 48 ± 29 mm depth from these land forms respectively. Up to 30 % of this loss could be directly attributable to the creation of the cross banks by bulldozer blading. The remainder was associated with mechanical losses due to export on truck tyres and bark, dust during the dry summer harvesting phase, and losses associated with sheet and rill erosion during storm events over the intervening years. Soil material eroded from the log landings was

  8. Street Prostitution Zones and Crime

    OpenAIRE

    Bisschop, Paul; Kastoryano, Stephen; van der Klaauw, Bas

    2015-01-01

    This paper studies the effects of introducing legal street prostitution zones on both registered and perceived crime. We exploit a unique setting in the Netherlands where legal street prostitution zones were opened in nine cities under different regulation systems. We provide evidence that the opening of these zones was not in response to changes in crime. Our difference-in-difference analysis using data on the largest 25 Dutch cities between 1994 and 2011 shows that opening a legal street pr...

  9. Erosion and sediment deposition evaluation in two slopes under different tillage systems using the '137Cs fallout' technique

    International Nuclear Information System (INIS)

    Arthur, Robson C.J.; Oliveira, Roberto A.S.; Bacchi, Osny O.S.; Correchel, Vladia; Santos, Dileia S.; Sparovek, Gerd

    2007-01-01

    With the increasing of occupation of the Brazilian Cerrado a series of environmental problems followed by the deforestation as soil erosion and soil compaction are appearing, and many of than are being related to the CT used. The NT cropping system which is being adopted more recently in the 'cerrado' region, has revealed benefic to the soil, mainly in terms of soil erosion control. The objective of the present work was to analyze the effect of the No Tillage NT and Conventional Tillage CT systems on the erosion process and to measure the efficiency of the riparian forest in trapping the sediments produced by erosion coming from crop areas cultivated by both systems trough the technique of 137Cs 'fallout' redistribution analysis. The study was carried out in Goiatuba/GO in two sampling dowslope transects located in areas of CT and NT cropping systems. Samples were taken from five points in transects of 200 and 140 meters long respectively, as well as from three soil profiles of a 30 m transect in the downstream riparian forests of each area. Incremental depth samples were also taken from two pits inside each transect in the forest down to 40 and 60 cm depth for the CT and NT respectively. The soil samples were air dried and sieved and the 137 Cs activity was analyzed for in a gamma ray detector (GEM-20180P, EG and ORTEC) coupled to a multichannel analyzer at CENA/USP. The results indicate variation of 137 Cs in soil profiles and high erosion rates for both cropping areas also indicate a movement of sediments from the two cropping areas to the riparian forest. (author)

  10. 75 FR 45011 - MainStreet Savings Bank, FSB, Hastings, MI; Notice of Appointment of Receiver

    Science.gov (United States)

    2010-07-30

    ... DEPARTMENT OF THE TREASURY Office of Thrift Supervision MainStreet Savings Bank, FSB, Hastings, MI... section 5(d)(2) of the Home Owners' Loan Act, the Office of Thrift Supervision has duly appointed the Federal Deposit Insurance Corporation as sole Receiver for MainStreet Savings Bank, Hastings, Michigan...

  11. Modern pollen and stomate deposition in lake surface sediments from across the treeline on the Kola Peninsula, Russia.

    Science.gov (United States)

    Gervais, B R.; MacDonald, G M.

    2001-04-01

    We sampled and analyzed surface sediments from 31 lakes along a latitudinal transect crossing the coniferous treeline on the Kola Peninsula, Russia. The major vegetation zones along the transect were tundra, birch-forest tundra, pine-forest tundra, and forest. The results indicate that the major vegetation types in our study area have distinct pollen spectra. Sum-of-squares cluster analysis and principal components analysis (PCA) groupings of pollen sites correspond to the major vegetation zones. PCA ordination of taxa indicates that the first axis separates taxa typical of the forest zone (Pinus, Picea) from taxa typical of tundra and forest-tundra zones (Polypodiaceae, Ericaceae, and Betula). The current position of the coniferous treeline, defined in our region by Pinus sylvestris, occurs roughly where Pinus pollen values reach 35% or greater. Arboreal pollen (AP)/non-arboreal pollen (NAP) ratios were calculated for each site and plotted against geographic distance along the transect. AP/NAP ratios of 7 or greater are found within pine-forest tundra and forest vegetation zones. Pinus stomates (dispersed stomatal guard cells) are absent from sites north of the coniferous treeline and all but two samples from the forested sites contain stomates. Stomate concentrations among the samples are highly variable and range from 10 to 458 per ml and positively correlate with the changing Pinus pollen values.

  12. Conditions of uranium-bearing calcite formation in ore-enclosing sediments of the Semizbaj deposit (Kazakhstan)

    International Nuclear Information System (INIS)

    Kondrat'eva, I.A.; Maksimova, I.G.; Dojnikova, O.I.

    1995-01-01

    Consideration is given to results of investigation into uranium-bearing calcite, forming the cement of gravelly-sandy rocks of the Semizbaj uranium deposit. Core sampling in prospecting boreholes were used to establish geological conditions, place and time of uranium-bearing calcite formation. Calcite was investigated by optical, electron-microscope and radiographic methods. It is shown that uranium in calcite doesn't form its own mineral phase and exists in scattered state. Uranium in calcite-bearing minerals is present in isomorphic form. Uranium content in calcite was equal to 0.009-0.15 %. It is proposed that mineralization, formed in sedimentary rocks by processes of ground-stratum oxidation, is the source of uranium, enriching calcite. refs., 5 figs., 2 tabs

  13. SEDIMENTATION AND DEPOSITIONAL ENVIRONMENT BASED ON SEISMIC AND DRILLING CORE ANALYSES IN CIMANUK DELTA INDRAMAYU, WEST JAVA

    Directory of Open Access Journals (Sweden)

    I Nyoman Astawa

    2017-07-01

    Full Text Available Core drilling had been carried out in three locations such as in Brondong Village (BH-01, Pasekan Village (BH-02, and Karangsong Village (BH-03. Those three cores are similar in lithology consist of clay. They are correlated based on fragment content, such as fine sand lenses, mollusk shells, rock and carbonate materials which discovered from different depths. Single side band of shallow seismic reflection recorded paleochannels in E sequence at the north and the west of investigated area. It’s predicted the north paleo channels were part of Lawas River or Tegar River, while the west paleo channels were part of Rambatan Lama River. Microfauna content of all those three cores indicated that from the depth of 0.00 meter down to 25,00 meters are Holocene/Recent, from 25,00 meters to the bottom are Pleistocene which were deposited in the bay to middle neritic environment.

  14. Street Papers, Work, and Begging

    DEFF Research Database (Denmark)

    Cockburn, Patrick Joseph

    2014-01-01

    Street papers are publications produced specifically for sale by the homeless and other vulnerable people in many countries around the world. Their social status is, however, often conspicuously unstable: ‘Get a job!’ has been reported as a common insult addressed to vendors, and street paper...

  15. The Regulation of Street Foods

    DEFF Research Database (Denmark)

    Forkour, John Boulard; Samuelsen, Helle; Yeboah, Eric Henry

    2017-01-01

    the challenges and negotiating strategies of regulators of street-vended foods in Ghana and analyses the implication for their relationship with street food vendors. The paper reveals that regulators operate in a context of limited resources, leading to a general feeling of neglect. In coping, regulators adopt...

  16. Effectiveness of green infrastructure for improvement of air quality in urban street canyons.

    Science.gov (United States)

    Pugh, Thomas A M; Mackenzie, A Robert; Whyatt, J Duncan; Hewitt, C Nicholas

    2012-07-17

    Street-level concentrations of nitrogen dioxide (NO(2)) and particulate matter (PM) exceed public health standards in many cities, causing increased mortality and morbidity. Concentrations can be reduced by controlling emissions, increasing dispersion, or increasing deposition rates, but little attention has been paid to the latter as a pollution control method. Both NO(2) and PM are deposited onto surfaces at rates that vary according to the nature of the surface; deposition rates to vegetation are much higher than those to hard, built surfaces. Previously, city-scale studies have suggested that deposition to vegetation can make a very modest improvement (street canyons. This study shows that increasing deposition by the planting of vegetation in street canyons can reduce street-level concentrations in those canyons by as much as 40% for NO(2) and 60% for PM. Substantial street-level air quality improvements can be gained through action at the scale of a single street canyon or across city-sized areas of canyons. Moreover, vegetation will continue to offer benefits in the reduction of pollution even if the traffic source is removed from city centers. Thus, judicious use of vegetation can create an efficient urban pollutant filter, yielding rapid and sustained improvements in street-level air quality in dense urban areas.

  17. Erosion and sediment deposition evaluation on slopes under different tillage systems in the Cerrado region using the 137Cs fallout technique

    International Nuclear Information System (INIS)

    Arthur, Robson Clayton Jacques

    2010-01-01

    In Brazil, the expansion of agricultural areas causes several problems on natural resources. With the increasing occupation of the Cerrado region by agriculture, a series of environmental problems like deforestation, soil erosion and soil compaction are appearing and causing radical transformations in the natural landscape due to removing almost all native vegetation. The conventional tillage system (CTS) is considered an inadequate form of soil management for its frequently irremediable consequences of soil compaction and soil erosion, and the no till system (NTS) makes the maintenance of the soil conditions possible, letting them close to the natural environment, thus reducing rates of soil erosion. The objective of this work was to evaluate the efficiency of riparian forests in the retention of sediments originated for three different tillage systems, through the fallout 137 CS redistribution technique, the Universal Soil Loss Equation (USLE) and some physical and chemical parameters that indicate the structural conditions of the soils of Goiatuba and Jandaia-GO. In the three areas, soil profiles were collected in three layers of 20 cm (0-20, 20-40 and 40-60 cm) at distinct points located along linear transects in the direction of the maximum slope until the riparian forest. In the riparian forest of each area, trenches were opened and soil was sampled to evaluate the activity of 137 Cs and the physical and chemical parameters of soil. Detection of the activity of 137 Cs was made with a gamma ray detector model (GEM-20180P, EG and ORTEC) connected to a multichannel analyzer. The comparison of averages was made using the Tukey test at 5% level of significance. The. results indicated that, the three soil tillage systems presented high rates of soil erosion and deposition of sediments and the riparian forest of the areas under CTS, NTS and pasture, located downstream received great amounts of sediments, and that only the riparian forest of CTS was capable to trap

  18. Violence in the Street, Violence of the Street

    DEFF Research Database (Denmark)

    Heinskou, Marie Bruvik; Liebst, Lasse Suonperä

    While in his early and general theory of interaction rituals Randall Collins emphasised that social situations are both ’symbolic’ and ’material’, the latter dimension is largely absent from Collins’ theory of violence(Collins 2004; 1993: 214). Compared with criminology’s more recent situational...... studies of violence, it is noticeable that the analytical success of these studies is closely linked with understanding street violence as a spatial-situational phenomenon (Clarke 1997; Eck & Weisburd 1995; Bragand & Weisburd; 2010; Wikström et al. 2012; Sampson et al. 1997). In light of evidence...... for the spatial concentration of street violence, this paper takes its point of departure in a large study of Street Violence among youth in Copenhagen, Denmark (combining quantitative data from filed police reports (N = 501), data from CCTV (N=100) and qualitative analysis of selected cases of street violence...

  19. Depositional record of trace metals and degree of contamination in core sediments from the Mandovi estuarine mangrove ecosystem, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Veerasingam, S.; Vethamony, P.; ManiMurali, R.; Fernandes, B.

    of sources. Enrichment of metals in bottom sediments represents a critical measure of health for any mangrove ecosystem (Janaki-Raman et al., 2007). Trace metals in coastal and estuarine sediments are incorporated into the aquatic food webs through primary... of susceptibility of the particles to the processes of physical and chemical weathering. The different morphological forms of iron oxides are well correlated with the sediment horizons. Spherical iron oxides predominate in the upper layers of sediment profiles...

  20. The impact of a tributary that carries high amounts of bed-load on the deposition of sediment downstream of a run-of river plant; Die Auswirkungen eines Geschiebe fuehrenden Zubringers auf die Verlandungssituation im Unterwasser eines Laufkraftwerkes

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Josef; Sindelar, Christine; Feldbacher, Rupert; Knoblauch, Helmut [TU Graz (Austria). Inst. fuer Wasserbau und Wasserwirtschaft

    2011-07-01

    For guaranteeing a sustainable sediment management on a chain of run-of river plants in the Salzach valley in Austria nearly annual flushings have been performed. The sediments that are removed out of the reservoirs tend to deposit immediately downstream of the dams mainly at the outlet of the turbines due to widening or reduced slope. During the physical model tests, which were performed for the hydro power plant St. Veit, it could be observed that the boundary conditions were obviously wrong because in the prototype much more sediment was settled as in the model. A downstream located tributary was found responsible because of its dumping of high amounts of bed load into the river Salzach. This led to a backwater flow respectively reduced shear stresses. Further model tests resulted in a successful solution which mitigates the situation substantially. (orig.)

  1. Safety of street: The role of street design

    Science.gov (United States)

    Rashid, Suhaila Abdul; Wahab, Mohammad Hussaini; Rani, Wan Nurul Mardiah Wan Mohd.; Ismail, Syuhaida

    2017-10-01

    Living in the cities poses many challenges for the vulnerable group of user especially women where they are exposed to many issues related to safety. With the changing of lifestyle and demands, women are expected to play multiple roles in the society and working is one of the tasks. When women are expected to be working as men do, they are no longer occupied at one place. Women nowadays travel on a daily basis and being in the streets is one of the important activities. With the influx of diverse group of people into the country, our streets are dominated by different types of people from different background. Due to these factors, there are possibilities of challenges and threats for users especially women. Therefore, city spaces especially the street become an important public realm for women. The design of the street should be able to make women feel safe as these are the public space where they spend time getting to and from work. The way women perceived their environment might be different from men especially when they fear of crime. Perception of safety will affect the quality of life where fear is an important psychological factor in human life. Living in fear will restrict human's freedom. Therefore, this study aimed to explore women's perception of safety in the streets of Kuala Lumpur. The study adopted a mixed-method approach of qualitative and quantitative in order to understand the safety perception among women that will later establish the relationship between built environment and human psychology. 120 respondents were selected randomly around Jalan Benteng, Jalan Tun Perak, Jalan Melaka and Jalan Melayu. Questionnaire survey forms were distributed and structured observation was conducted at interval period at these streets to examined and assess women's behavior. Finding shows that fear does affect women's perception and physical design of the streets are important in affecting their behavior.

  2. Uranium accumulation in modern and ancient Fe-oxide sediments: Examples from the Ashadze-2 hydrothermal sulfide field (Mid-Atlantic Ridge) and Yubileynoe massive sulfide deposit (South Urals, Russia)

    Science.gov (United States)

    Ayupova, N. R.; Melekestseva, I. Yu.; Maslennikov, V. V.; Tseluyko, A. S.; Blinov, I. A.; Beltenev, V. E.

    2018-05-01

    Fe-oxyhydroxide sediments (gossans) from the Ashadze-2 hydrothermal sulfide field (Mid-Atlantic Ridge) and hematite-carbonate-quartz rocks (gossanites) from the Yubileynoe Cu-Zn VHMS deposit (South Urals) are characterized by anomalously high U contents (up to 352 ppm and 73 ppm, respectively). In gossans from the Ashadze-2 hydrothermal sulfide field, rare isometric anhedral uraninite grains (up to 2 μm) with outer P- and Ca-rich rims, and numerous smaller (<1 μm) grains, occur in Fe-oxyhydroxides and sepiolite, associated with pyrite, isocubanite, chalcopyrite, galena, atacamite and halite. In gossanites from the Yubileynoe deposit, numerous uraninite particles (<3 μm) are associated with apatite, V-rich Mg-chlorite, micro-nodules of pyrite, Se-bearing galena, hessite and acanthite in a hematite-carbonate-quartz matrix. Small (1-3 μm) round grains of uraninite, which locally coalesce to large grains up to 10 μm in size, are associated with authigenic chalcopyrite. The similar diagenetic processes of U accumulation in modern and ancient Fe-oxyhydroxide sediments were the result of U fixation from seawater during the oxidation of sulfide minerals. Uraninite in gossanites was mainly deposited from diagenetic pore fluids, which circulated in the sulfide-hyaloclast-carbonate sediments.

  3. USGS environmental characterization of flood sediments left in the New Orleans area after Hurricanes Katrina and Rita, 2005--Progress Report

    Science.gov (United States)

    Plumlee, Geoffrey S.; Meeker, Gregory P.; Lovelace, John K.; Rosenbauer, Robert J.; Lamothe, Paul J.; Furlong, Edward T.; Demas, Charles R.

    2006-01-01

    Introduction: The flooding in the greater New Orleans area that resulted from Hurricanes Katrina and Rita in September, 2005, left behind accumulations of sediments up to many centimeters thick on streets, lawns, parking lots, and other flat surfaces. These flood sediment deposits have been the focus of extensive study by the US Environmental Protection Agency (EPA) and Louisiana Department of Environmental Quality (LDEQ) due to concerns that the sediments may contain elevated levels of heavy metals, organic contaminants, and microbes. The U.S. Geological Survey (USGS) is characterizing a limited number of flood sediment samples that were collected on September 15-16 and October 6-7, 2005, from the greater New Orleans area by personnel from the USGS Louisiana Water Science Center in Baton Rouge. Small samples (< 3 pints each) of wet to dry flood sediment were collected from 11 localities around downtown New Orleans on September 15, 2005, and two large samples (40 pints each) of wet flood sediment were collected from the Chalmette area on September 16. Twelve additional samples (8-10 pints each) were collected from New Orleans, Slidell, Rigolets, and Violet on October 6 and 7. The USGS characterization studies of these flood sediments are designed to produce data and interpretations regarding how the sediments and any contained contaminants may respond to environmental processes. This information will be of use to cleanup managers and DoI/USGS scientists assessing environmental impacts of the hurricanes and subsequent cleanup activities.

  4. 75 FR 34533 - Deposits

    Science.gov (United States)

    2010-06-17

    ... collection request (ICR) described below has been submitted to the Office of Management and Budget (OMB) for..., Attention: Desk Officer for OTS, U.S. Office of Management and Budget, 725 17th Street, NW., Room 10235... statement the institution sends to the consumer. Regulation DD contains rules for advertisements of deposit...

  5. Trees and Streets as Drivers of Urban Stormwater Nutrient Pollution.

    Science.gov (United States)

    Janke, Benjamin D; Finlay, Jacques C; Hobbie, Sarah E

    2017-09-05

    Expansion of tree cover is a major management goal in cities because of the substantial benefits provided to people, and potentially to water quality through reduction of stormwater volume by interception. However, few studies have addressed the full range of potential impacts of trees on urban runoff, which includes deposition of nutrient-rich leaf litter onto streets connected to storm drains. We analyzed the influence of trees on stormwater nitrogen and phosphorus export across 19 urban watersheds in Minneapolis-St. Paul, MN, U.S.A., and at the scale of individual streets within one residential watershed. Stormwater nutrient concentrations were highly variable across watersheds and strongly related to tree canopy over streets, especially for phosphorus. Stormwater nutrient loads were primarily related to road density, the dominant control over runoff volume. Street canopy exerted opposing effects on loading, where elevated nutrient concentrations from trees near roads outweighed the weak influence of trees on runoff reduction. These results demonstrate that vegetation near streets contributes substantially to stormwater nutrient pollution, and therefore to eutrophication of urban surface waters. Urban landscape design and management that account for trees as nutrient pollution sources could improve water quality outcomes, while allowing cities to enjoy the myriad benefits of urban forests.

  6. Microbial Mn(IV) and Fe(III) reduction in northern Barents Sea sediments under different conditions of ice cover and organic carbon deposition

    DEFF Research Database (Denmark)

    Nickel, Maren; Vandieken, Verona; Brüchert, Volker

    2008-01-01

    station, with seasonally extended ice cover, low organic carbon content and sedimentation rate combined with relatively high concentrations of Mn and Fe(III) oxides favored dissimilatory Fe and Mn reduction (98% of anaerobic carbon oxidation) over sulfate reduction in the top 12 cm of the sediment....... In contrast, in a sediment that had not been ice covered for at least 12 months and with more organic carbon and a higher sedimentation rate, sulfate reduction was the most important anaerobic electron-accepting process (>80% of anaerobic carbon oxidation). In the upper 3 cm, microbial Fe and sulfate...

  7. Multiple sources of selenium in ancient seafloor hydrothermal systems: Compositional and Se, S, and Pb isotopic evidence from volcanic-hosted and volcanic-sediment-hosted massive sulfide deposits of the Finlayson Lake District, Yukon, Canada

    Science.gov (United States)

    Layton-Matthews, Daniel; Leybourne, Matthew I.; Peter, Jan M.; Scott, Steven D.; Cousens, Brian; Eglington, Bruce M.

    2013-09-01

    Volcanic-hosted massive sulfide (VHMS) and volcanic-sediment-hosted massive sulfide (VSHMS; i.e., hosted by both volcanic and sedimentary rocks) deposits in the Finlayson Lake District, Yukon, Canada, provide a unique opportunity to study the influence of seafloor and sub-seafloor hydrothermal processes on the formation of Se-poor (GP4F VHMS deposit; 7 ppm Se average), intermediate (Kudz Ze Kayah—KZK VHMS deposit; 200 ppm Se average), and Se-enriched (Wolverine VSHMS deposit; 1100 ppm Se average) mineralization. All three deposits are hosted by mid-Paleozoic (˜360-346 Ma) felsic volcanic rocks, but only the Wolverine deposit has voluminous coeval carbonaceous argillites (black shales) in the host rock package. Here we report the first application of Se isotope analyses to ancient seafloor mineralization and use these data, in conjunction with Pb and S isotope analyses, to better understand the source(s) and depositional process(es) of Se within VHMS and VSHMS systems. The wide range of δ82Se (-10.2‰ to 1.3‰, relative to NIST 3149), δ34S (+2.0‰ to +12.8‰ CDT), and elevated Se contents (up to 5865 ppm) within the Wolverine deposit contrast with the narrower range of δ82Se (-3.8‰ to -0.5‰), δ34S (9.8‰ to 13.0‰), and lower Se contents (200 ppm average) of the KZK deposit. The Wolverine and KZK deposits have similar sulfide depositional histories (i.e., deposition at the seafloor, with concomitant zone refining). The Se in the KZK deposit is magmatic (leaching or degassing) in origin, whereas the Wolverine deposit requires an additional large isotopically negative Se source (i.e. ˜-15‰ δ82Se). The negative δ82Se values for the Wolverine deposit are at the extreme light end for measured terrestrial samples, and the lightest observed for hypogene sulfide minerals, but are within calculated equilibrium values of δ82Se relative to NIST 3149 (˜30‰ at 25 °C between SeO4 and Se2-). We propose that the most negative Se isotope values at the

  8. Modelling traffic pollution in streets

    Energy Technology Data Exchange (ETDEWEB)

    Berkowicz, R.; Hertel, O. [National Environmental Research Inst., Dept. of Atmospheric Environment, Roskilde (Denmark); Larsen, S.E.; Soerensen, N.N.; Nielsen, M. [Risoe National Lab., Dept. of Meteorology and Wind Energy, Roskilde (Denmark)

    1997-01-01

    This report concerns mainly the subject related to modelling air pollution from traffic in urban streets. A short overview is presented over the theoretical aspects and examples of most commonly used methods and models are given. Flow and dispersion conditions in street canyons are discussed and the presentation is substantiated with the analysis of the experimental data. The main emphasis is on the modelling methods that are suitable for routine applications and a more detailed presentation is given of the Operational Street Pollution Model (OSPM), which was developed by the National Environmental Research Institute. The model is used for surveillance of air pollution from traffic in Danish cities and also for special air pollution studies. (au) 76 refs.

  9. The (Street) Art of Resistance

    DEFF Research Database (Denmark)

    Awad, Sarah H.; Wagoner, Brady; Glaveanu, Vlad Petre

    2017-01-01

    This chapter focuses on the interrelation between resistance, novelty and social change We will consider resistance as both a social and individual phenomenon, a constructive process that articulates continuity and change and as an act oriented towards an imagined future of different communities....... In this account, resistance is thus a creative act having its own dynamic and, most of all, aesthetic dimension. In fact, it is one such visibly artistic form of resistance that will be considered here, the case of street art as a tool of social protest and revolution in Egypt. Street art is commonly defined...... in sharp contrast with high or fine art because of its collective nature and anonymity, its different kind of aesthetics, and most of all its disruptive, ‘anti-social’ outcomes. With the use of illustrations, we will argue here that street art is prototypical of a creative form of resistance, situated...

  10. Sensation Seeking in Street Violence

    DEFF Research Database (Denmark)

    Heinskou, Marie Bruvik; Liebst, Lasse Suonperä

    Sensation seeking leads to violence—runs an influential hypothesis in the social scientific study of violent behavior. Although studies confirm that violence is sometimes structured by sensation-seeking motives, the literature seldom comments on the limits to this explanation of violence....... The present study examines the scale of violence motivated by sensation seeking and the degree to which there are several distinct forms of sensation seeking motives operative in violence, rather than a sensation-seeking motive in the singular. The study draws on a sample of situations from Copenhagen...... involving street violence, which are coded quantitatively and qualitatively. Our analysis shows that sensation seeking only seldom seems to play a role in the structuring of street violence. Moreover, the data indicate that sensation seeking finds expression in street violence situations in two different...

  11. Mean Streets: An analysis on street level pollution in NYC

    Science.gov (United States)

    Parker, G.

    2017-12-01

    The overarching objective of this study is to quantify the spatial and temporal variability in particulatematter concentration (PM 2.5) along crowded streets in New York City. Due to their fine size and lowdensity PM 2.5 stays longer in the atmosphere and could bypass human nose and throat and penetratedeep in to the lungs and even enter the circulatory system. PM 2.5 is a by-product of automobilecombustion and is a primary cause of respiratory malfunction in NYC. The study would monitor streetlevel concentration of PM2.5 across three different routes that witness significant pedestrian traffic;observations will be conducted along these three routes at different time periods. The study will use theAirBeam community air quality monitor. The monitor tracks PM 2.5 concentration along with GPS, airtemperature and relative humidity. The surface level concentration monitored by AirBeam will becompared with atmospheric concentration of PM 2.5 that are monitored at the NOAA CREST facility onCCNY campus. The lower atmospheric values will be correlated with street level values to assess thevalidity of using of lower atmospheric values to predict street level concentrations. The street levelconcentration will be compared to the air quality forecasted by the New York Department ofEnvironment Conservation to estimate its accuracy and applicability.

  12. Street photography as social interaction

    Directory of Open Access Journals (Sweden)

    Andrea Mubi Brighenti

    2009-06-01

    Full Text Available Street photographers know quite well that taking a picture is a form of social interaction. The birth of this genre of photography, they have been discussing at length about the ethical problems involved in taking pictures of personal strangers in public places without asking permission.

  13. Wary Eyes Monitoring Wall Street

    Science.gov (United States)

    Jacobson, Linda

    2008-01-01

    School business officials kept a close watch on the financial markets this week--and on district investment portfolios and teacher-retirement funds--as stock prices gyrated and once-sound institutions got government bailouts or crumbled into bankruptcy. While financial observers said it was too soon to predict how Wall Street's upheaval might…

  14. Street prostitution zones and crime

    NARCIS (Netherlands)

    Bisschop, P.; Kastoryano, S.; van der Klaauw, B.

    2017-01-01

    This paper studies the effects of legal street prostitution zones on registered and perceived crime. We exploit a unique setting in the Netherlands where these tippelzones were opened in nine cities under different regulation systems. Our difference-in-difference analysis of 25 Dutch cities between

  15. Post depositional memory record of mercury in sediment near effluent disposal site of a chlor-alkali plant in Thane Creek-Mumbai Harbour, India

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.; Rokade, M.A.; Zingde, M.D.; Borole, D.V.

    in landfills, mine tailings, contaminated industrial sites, soils and sediments. Estuaries and coastal marine regions form an essential link in the global biogeochemical cycling of Hg between the terrestrial environment - the major repository for atmospheric... by close relationship with organic matter, and Fe and Al oxides or sorbed onto the mineral particles [8]. Hence, sediments adjacent to the outfalls of chlor-alkali plants frequently contain high levels of Hg [7,10-15]. Some natural processes (water, soil...

  16. Street Pastors : on security, care and faith

    NARCIS (Netherlands)

    van Steden, R.

    2018-01-01

    This paper presents a study of Street Pastors in Cardiff, the capital city of Wales. Street Pastors are Christian volunteers who look after vulnerable people in the night-time economy. In this manner, they provide ‘securitas’ through empathy and care. The motives of Street Pastors for engaging with

  17. School Me, School Me Not, Street Me, Street Me Not…

    DEFF Research Database (Denmark)

    Gravesen, David Thore; Frostholm, Peter Hornbæk

    School Me, School Me Not, Street Me, Street Me Not… (1099) David Thore Gravesen, Peter Hornbæk Frostholm ECER 2016, 14. Communities, Families and Schooling in Educational Research, Session: 14 SES 10 A When picking leaves of a marguerite, whilst doing the “she loves me, she loves me not” game, you....... Obviously, the skaters attend the site to skate. But also other, more vulnerable groupings, use the site to socialize, meet peers and perhaps escape an unreliable and risky family arena. One particular group, the self-named Thugz, primarily formed around a number of young boys with non-Danish ethnic...... milieu. With a criminal gang-like behavior (Hoeben & Weerman 2013; Hviid 2007; Rasmussen 2012) involving petty crime and violence, one would think the group members would be indifferent towards their schooling and future careers. This was not the case. The informants proved to be very aware...

  18. Early diagenesis in the sediments of the Congo deep-sea fan dominated by massive terrigenous deposits: Part III - Sulfate- and methane- based microbial processes

    Science.gov (United States)

    Pastor, L.; Toffin, L.; Decker, C.; Olu, K.; Cathalot, C.; Lesongeur, F.; Caprais, J.-C.; Bessette, S.; Brandily, C.; Taillefert, M.; Rabouille, C.

    2017-08-01

    Geochemical profiles (SO42-, H2S, CH4, δ13CH4) and phylogenetic diversity of Archaea and Bacteria from two oceanographic cruises dedicated to the lobes sediments of the Congo deep-sea fan are presented in this paper. In this area, organic-rich turbidites reach 5000 m and allow the establishment of patchy cold-seep-like habitats including microbial mats, reduced sediments, and vesicomyid bivalves assemblages. These bivalves live in endosymbiosis with sulfur-oxidizing bacteria and use sulfides to perform chemosynthesis. In these habitats, unlike classical abyssal sediments, anoxic processes are dominant. Total oxygen uptake fluxes and methane fluxes measured with benthic chambers are in the same range as those of active cold-seep environments, and oxygen is mainly used for reoxidation of reduced compounds, especially in bacterial mats and reduced sediments. High concentrations of methane and sulfate co-exist in the upper 20 cm of sediments, and evidence indicates that sulfate-reducing microorganisms and methanogens co-occur in the shallow layers of these sediments. Simultaneously, anaerobic oxidation of methane (AOM) with sulfate as the electron acceptor is evidenced by the presence of ANMEs (ANaerobic MEthanotroph). Dissolved sulfide produced through the reduction of sulfate is reoxidized through several pathways depending on the habitat. These pathways include vesicomyid bivalves uptake (adults or juveniles in the bacterial mats habitats), reoxidation by oxygen or iron phases within the reduced sediment, or reoxidation by microbial mats. Sulfide uptake rates by vesicomyids measured in sulfide-rich sea water (90±18 mmol S m-2 d-1) were similar to sulfide production rates obtained by modelling the sulfate profile with different bioirrigation constants, highlighting the major control of vesicomyids on sulfur cycle in their habitats.

  19. Street art - vandalismus nebo umění?

    OpenAIRE

    Grabmüllerová, Eva

    2012-01-01

    The diploma thesis ‚Street Art - Vandalism or Art?' deals with a world-wide phenomenon of contemporary art. The thesis focuses on the characterization of street art and history of street art (its origin and development) and analyzes the difference between street art and graffiti. The thesis presents street art techniques as well as notable street artists. The thesis also observes street art scene in the Czech Republic and depicts features that street art has in common with other art movements...

  20. COMMON GROUNDS BETWEEN PRINTMAKING AND STREET ART

    Directory of Open Access Journals (Sweden)

    Burcak Balamber

    2016-09-01

    Full Text Available Graffiti movement, born as a result of an effort of the youth, who felt themselves socially excluded and alone, to show their existence and identities during the 1960s, expanded its scope owing to street based artists such as Keith Haring and Jean-Michel Basquiat entering to the galleries, and transformed into an artistic manner of expression having aesthetic concerns by adopting a more inclusive definition ‘street art’. During this transformation of street art,street artists experimented with various methods from many different disciplines and hence created works in a wide range of varieties in terms of plastic and artistic values. Among these disciplines, printmakinghastaken its own place in street artas a discipline thatdeeply influenced street artists.Printmaking has fascinated street artists and become a part of their production process, not only with its philosophy sharing common grounds with street art and advantages in terms of its tecnical practices but also its unique plastic and linear values.Thanks to the opportunities of printmaking, street art has succeeded creating a tremendous impression worldwide, and even positioned itself into today’s greatest museums/gallery halls. This article aims to show how and in what way printmaking has influenced street art being in a transformation since the 1960s, and to put an emphasis on theimportance of printmaking on today’s street art.

  1. Renaming Zagreb Streets and Squares

    Directory of Open Access Journals (Sweden)

    Jelena Stanić

    2009-06-01

    Full Text Available The paper deals with changes in street names in the city of Zagreb. Taking the Lower Town (Donji grad city area as an example, the first part of the paper analyses diachronic street name changes commencing from the systematic naming of streets in 1878. Analysis of official changes in street names throughout Zagreb’s history resulted in categorisation of five periods of ideologically motivated naming/name-changing: 1. the Croatia modernisation period, when the first official naming was put into effect, with a marked tendency towards politicisation and nationalisation of the urban landscape; 2. the period of the Kingdom of the Serbs, Croatians and Slovenians/Yugoslavia, when symbols of the new monarchy, the idea of the fellowship of the Southern Slavs, Slavenophilism and the pro-Slavic geopolitical orientation were incorporated into the street names, and when the national idea was highly evident and remained so in that process; 3. the period of the NDH, the Independent State of Croatia, with decanonisation of the tokens of the Yugoslavian monarchy and the Southern Slavic orientation, and reference to the Ustashi and the German Nazi and Italian Fascist movement; 4. the period of Socialism, embedding the ideals and heroes of the workers’ movement and the War of National Liberation into the canonical system; and, 5. the period following the democratic changes in 1990, when almost all the signs of Socialism and the Communist/Antifascist struggle were erased, with the prominent presence of a process of installing new references to early national culture and historical tradition. The closing part of the paper deals with public discussions connected with the selection of a location for a square to bear the name of the first president of independent Croatia, Franjo Tuđman. Analysis of these public polemics shows two opposing discourses: the right-wing political option, which supports a central position for the square and considers the chosen area to

  2. Geochemical and multi-isotopic (87Sr/86Sr, 143Nd/144Nd, 238U/235U) perspectives of sediment sources, depositional conditions, and diagenesis of the Marcellus Shale, Appalachian Basin, USA

    Science.gov (United States)

    Phan, Thai T.; Gardiner, James B.; Capo, Rosemary C.; Stewart, Brian W.

    2018-02-01

    We investigate sediment sources, depositional conditions and diagenetic processes affecting the Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, a major target of natural gas exploration. Multiple proxies, including trace metal contents, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U isotopes were applied to whole rock digestions and sequentially extracted fractions of the Marcellus shale and adjacent units from two locations in the Appalachian Basin. The narrow range of εNd values (from -7.8 to -6.4 at 390 Ma) is consistent with derivation of the clastic sedimentary component of the Marcellus Shale from a well-mixed source of fluvial and eolian material of the Grenville orogenic belt, and indicate minimal post-depositional alteration of the Sm-Nd system. While silicate minerals host >80% of the REE in the shale, data from sequentially extracted fractions reflect post-depositional modifications at the mineralogical scale, which is not observed in whole rock REE patterns. Limestone units thought to have formed under open ocean (oxic) conditions have δ238U values and REE patterns consistent with modern seawater. The δ238U values in whole rock shale and authigenic phases are greater than those of modern seawater and the upper crust. The δ238U values of reduced phases (the oxidizable fraction consisting of organics and sulfide minerals) are ∼0.6‰ greater than that of modern seawater. Bulk shale and carbonate cement extracted from the shale have similar δ238U values, and are greater than δ238U values of adjacent limestone units. We suggest these trends are due to the accumulation of chemically and, more likely, biologically reduced U from anoxic to euxinic bottom water as well as the influence of diagenetic reactions between pore fluids and surrounding sediment and organic matter during diagenesis and catagenesis.

  3. Pollutant Dilution and Diffusion in Urban Street Canyon Neighboring Streets

    Science.gov (United States)

    Sun, Z.; Fu, Zh. M.

    2011-09-01

    In the present study we investigated the airflow patterns and air quality of a series of typical street canyon combinations, developed a mass balance model to determine the local pollutant dilution rate, and discuss the impact of upstream canyon on the air quality of downstream canyon. The results indicated that the geometrical size of upstream and downstream buildings have significant impacts on the ambient airflow patterns. The pollution distribution within the canyons varies with different building combinations and flow patterns. Within the upstream canyon, pollution always accumulates to the low building side for non-symmetrical canyon, and for symmetrical canyon high level of pollution occurs at the leeward side. The height of the middle and downstream buildings can evidently change the pollutant dispersion direction during the transport process. Within the polluted canyon, the pollutant dilution rate (PDR) also varies with different street canyon combinations. The highest PDR is observed when the upstream buildings are both low buildings no matter the height of downstream building. However, the two cases are likely to contribution pollution to the downstream canyon. The H-L-H combination is mostly against local pollution remove, while the L-H-L case is considered the best optimistic building combination with both the ability of diluting local pollution and not remarkably decreasing air quality of downstream canyon. The current work is expected instructive for city designers to optimize traffic patterns under typical existing geometry or in the development of urban geometry modification for air quality control.

  4. Structural value of Yerevan streets

    Directory of Open Access Journals (Sweden)

    Avetisyan Arsen Grantovich

    2015-04-01

    Full Text Available The absence of the methods of urban analysis in the process of urban development of Yerevan is the reason of urban planning activities that tend to decrease the urban value of Yerevan territories. Meanwhile the studies in the sphere of urban planning and urban analysis prove the dependence of the life in the city on its structure and distribution of the functions. The mentioned issue highlights the importance of urban analysis. The paper discusses space syntax, which is one of the initial methods of urban analysis. The basic concept of Space syntax is based on the assumption that urban fabric can be presented and studied as a power graph. The method provides the measures that evaluate the land use, traffic and pedestrian movement, land value and even carbon emissions. The paper discusses also recent attempts of integration of space syntax method into GIS environment. GIS databases provide researchers with vast amount of urban data. Analyses presented in the current paper were performed on the basis of the open street map, which was imported from the GIS environment. With the application of space syntax methods analysis of connectivity, integration choice (betweenness and depth from the city center were performed to evaluate the structural value of Yerevan streets. Municipal regions of Yerevan were classified by the level of their accessibility and by their distances from the city center on the base of the results of depth measures from the city center. Evaluation of the street network aims to define the most integrated and centrally positioned parts of the city. These areas can be locations for the organization of sub centers of Yerevan in the municipal regions.

  5. A Paleogeographic and Depositional Model for the Neogene Fluvial Succession, Pishin Belt, Northwest Pakistan: Effect of Post Collisional Tectonics on Sedimentation in a Peripheral Foreland Setting

    DEFF Research Database (Denmark)

    Kasi, Aimal Khan; Kassi, Akhtar Muhammad; Umar, Muhammad

    2018-01-01

    . During the Early Miocene, subaerial sedimentation started after the final closure of the Katawaz Remnant Ocean. Based on detailed field data, twelve facies were recognized in Neogene successions exposed in the Pishin Belt. These facies were further organized into four facies associations i.e. channels......‐story sandstone and/or conglomerate channels, lateral accretion surfaces (point bars) and alluvial fans. Neogene sedimentation in the Pishin Belt was mainly controlled by active tectonism and thrusting in response to the oblique collision of the Indian Plate with the Afghan Block of the Eurasian Plate along......, crevasse splay, natural levee and floodplain facies associations. Facies associations and variations provided ample evidence to recognize a number of fluvial architectural components in the succession e.g., low‐sinuosity sandy braided river, mixed‐load meandering, high‐sinuosity meandering channels, single...

  6. Toxic trace element assessment for soils/sediments deposited during Hurricanes Katrina and Rita from southern Louisiana, USA: a sequential extraction analysis.

    Science.gov (United States)

    Shi, Honglan; Witt, Emitt C; Shu, Shi; Su, Tingzhi; Wang, Jianmin; Adams, Craig

    2010-07-01

    Analysis of soil/sediment samples collected in the southern Louisiana, USA, region three weeks after Hurricanes Katrina and Rita passed was performed using sequential extraction procedures to determine the origin, mode of occurrence, biological availability, mobilization, and transport of trace elements in the environment. Five fractions: exchangeable, bound to carbonates, bound to iron (Fe)-manganese (Mn) oxides, bound to organic matter, and residual, were subsequently extracted. The toxic trace elements Pb, As, V, Cr, Cu, and Cd were analyzed in each fraction, together with Fe in 51 soil/sediment samples. Results indicated that Pb and As were at relatively high concentrations in many of the soil/sediment samples. Because the forms in which Pb and As are present tend to be highly mobile under naturally occurring environmental conditions, these two compounds pose an increased health concern.Vanadium and Cr were mostly associated with the crystal line nonmobile residual fraction. A large portion of the Cu was associated with organic matter and residual fraction. Cadmium concentrations were low in all soil/sediment samples analyzed and most of this element tended to be associated with the mobile fractions. An average of 21% of the Fe was found in the Fe-Mn oxide fraction, indicating that a substantial part of the Fe was in an oxidized form. The significance of the overall finding of the present study indicated that the high concentrations and high availabilities of the potentially toxic trace elements As and Pb may impact the environment and human health in southern Louisiana and, in particular, the New Orleans area. Copyright (c) 2010 SETAC.

  7. Tracing time in the ocean: Unraveling depositional and preservational timescales using compound-specific radiocarbon analysis of biomarkers from marine sediments

    OpenAIRE

    Kusch, Stephanie

    2010-01-01

    Carbon cycle dynamics between the different inorganic and organic carbon pools play an important role in controlling the atmospheric chemical composition, thus, regulating the Earth’s climate. Atmospheric CO2 is fixed into biomass by photosynthesis of terrestrial and marine primary producers. Until final burial in marine sediments, the biologically fixed carbon that escapes remineralisation undergoes exchange between various active carbon reservoirs. Until now, the timescales o...

  8. PLC based Smart Street Lighting Control

    OpenAIRE

    D.V.Pushpa Latha; K.R.Sudha; Swati Devabhaktuni

    2013-01-01

    Conventional street lighting systems in most of the areas are Online at regular intervals of time irrespective of the seasonal variations. The street lights are simply switched on at afternoon and turned off in the morning. The consequence is that a large amount of Power is wasted meaninglessly. As energy consumption is an issue of increasing interest, possible energy savings in public street lighting systems are recently discussed from different viewpoints. The purpose of this work is to des...

  9. Luminescence dating of Netherland's sediments

    NARCIS (Netherlands)

    Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

    2007-01-01

    Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments;

  10. Changes in Sediment Fatty Acid Composition during Passage through the Gut of Deposit Feeding Holothurians: Holothuria atra (Jaeger, 1883 and Holothuria leucospilota (Brandt, 1835

    Directory of Open Access Journals (Sweden)

    Prosper L. Mfilinge

    2016-01-01

    Full Text Available Sea cucumbers Holothuria atra and Holothuria leucospilota play an important role in the bioturbation of sediment in coral reef and rocky intertidal ecosystems. This study investigated changes in sediment fatty acid (FA composition during gut passage in H. atra and H. leucospilota. The FA composition did not differ significantly between species. Comparison of FA composition in ambient sediment (AS, foregut (FG, midgut (MG, hindgut (HG, and faecal pellets (FPs indicated that marked changes in FA composition occurred during passage through the gut of H. atra and H. leucospilota. Saturated fatty acids (SAFAs, monounsaturated fatty acids (MUFAs, polyunsaturated fatty acids (PUFAs, and branched fatty acids (BrFAs were significantly higher in FG than in AS, suggesting that both species selectively ingested nutrient rich particles. Significant reduction of SAFAs, MUFAs, PUFAs, and BrFAs occurred in MD and HD, with complete elimination of most PUFAs in FPs. A decrease in PUFAs 20:5ω3, 18:4ω3, 22:5ω3, 22:6ω3, 18:2ω6, 18:3ω3, 18:3ω6, odd-numbered BrFAs, and MUFA 18:1ω7 indicated that algal detritus and bacteria were important part of diet. These results have implications for the fate of specific dietary FAs, especially ω3 and ω6, and the contribution holothurian FPs make to the FA composition of coral reef and rocky intertidal ecosystems.

  11. Changes in Sediment Fatty Acid Composition during Passage through the Gut of Deposit Feeding Holothurians: Holothuria atra (Jaeger, 1883) and Holothuria leucospilota (Brandt, 1835)

    Science.gov (United States)

    Tsuchiya, Makoto

    2016-01-01

    Sea cucumbers Holothuria atra and Holothuria leucospilota play an important role in the bioturbation of sediment in coral reef and rocky intertidal ecosystems. This study investigated changes in sediment fatty acid (FA) composition during gut passage in H. atra and H. leucospilota. The FA composition did not differ significantly between species. Comparison of FA composition in ambient sediment (AS), foregut (FG), midgut (MG), hindgut (HG), and faecal pellets (FPs) indicated that marked changes in FA composition occurred during passage through the gut of H. atra and H. leucospilota. Saturated fatty acids (SAFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and branched fatty acids (BrFAs) were significantly higher in FG than in AS, suggesting that both species selectively ingested nutrient rich particles. Significant reduction of SAFAs, MUFAs, PUFAs, and BrFAs occurred in MD and HD, with complete elimination of most PUFAs in FPs. A decrease in PUFAs 20:5ω3, 18:4ω3, 22:5ω3, 22:6ω3, 18:2ω6, 18:3ω3, 18:3ω6, odd-numbered BrFAs, and MUFA 18:1ω7 indicated that algal detritus and bacteria were important part of diet. These results have implications for the fate of specific dietary FAs, especially ω3 and ω6, and the contribution holothurian FPs make to the FA composition of coral reef and rocky intertidal ecosystems. PMID:27042355

  12. [Street prostitution and drug addiction].

    Science.gov (United States)

    Ishøy, Torben; Ishøy, Pelle Lau; Olsen, Lis Raabaek

    2005-09-26

    Street-based prostitution accounts for 10% of the prostitution activity in Denmark, mainly involving female drug addicts. We studied a group of women with a common history of substance abuse and their comparative psychosocial characteristics, correlated with whether they had previously been a prostitute or not. Their psychic symptoms were evaluated and compared with those of controls. 27 females receiving maintenance treatment for substance abuse completed a questionnaire dealing with their social background, substance abuse profile, and history of sexual abuse and prostitution, as well as their current health status, including SCL-90. The scores were compared to those of a control group of an age- and gender-matched Danish standard population. Neglect in childhood and adulthood corresponded to international findings. 14 of the women had previous sex-trading experience, and early use of heroin and cocaine was a predictor for starting a career in prostitution. The SCL-90 scores for the dimensions of somatization and depression were significantly higher for drug-abusing women in general than in the control group. The scores of drug-abusing former prostitutes were similarly significantly higher on most of the dimensions except the hostility dimension when compared to those of drug-abusing women who had never been involved in prostitution. Rape and domestic violence were characteristic phenomena among drug-abusing prostitutes (p prostitution. Various psychosocial stress factors among street-based prostitutes indicate the need for broader psychiatric approaches in Danish drug addiction maintenance programmes.

  13. Georges Charpak street sign unveiled

    CERN Multimedia

    Paola Catapano

    2011-01-01

    While it might not be the only French street named in honour of the late Georges Charpak, who passed away in September 2010 at the age of 87, the street chosen by the mayor of Saint-Genis-Pouilly is certainly the only one located directly opposite the CERN "campus". The road overlooks buildings on the CERN Meyrin site, where Georges Charpak spent most of his career as a physicist, conducting the research that won him the Nobel Prize in Physics in 1992.   From left to right: Sigurd Lettow, Dominique Charpak and the mayor of Saint-Genis-Pouilly. The unveiling took place on 17 October and was organised by the mayor of Saint-Genis-Pouilly. George Charpak’s wife, Dominique, and Sigurd Lettow, CERN Director of Administration and General Infrastructure, attended what was an intimate and touching ceremony. The mayor’s speech at the event praised Georges’ commitment to scientific education. The highlight of the event, however, was a witty and humorous ...

  14. Draa Sfar, Morocco: A Visean (331 Ma) pyrrhotite-rich, polymetallic volcanogenic massive sulphide deposit in a Hercynian sediment-dominant terrane

    OpenAIRE

    Marcoux , Eric; Belkabir , Abdelhay; Gibson , Harold L.; Lentz , David; Ruffet , Gilles

    2008-01-01

    International audience; Draa Sfar is a Visean, stratabound, volcanogenic massive sulphide ore deposit hosted by a Hercynian carbonaceous, black shale-rich succession of the Jebilet terrane, Morocco. The ore deposit contains 10 Mt grading 5.3 wt.% Zn, 2 wt.% Pb, and 0.3 wt.% Cu within two main massive sulphides orebodies, Tazakourt (Zn-rich) and Sidi M'Barek (Zn–Cu rich). Pyrrhotite is by far the dominant sulphide (70 to 95% of total sulphides), sphalerite is fairly abundant, chalcopyrite and ...

  15. Sedimentation of the basal Kombolgie Formation (Upper Precambrian-Carpentarian) Northern Territory, Australia: possible significance in the genesis of the underlying Alligator Rivers unconformity-type uranium deposits

    International Nuclear Information System (INIS)

    Ojakangas, R.W.

    1979-10-01

    The 1400 to 1500 My old Kombolgie Formation of the MacArthur Basin of the Northern Territory overlies or has overlain unconformity-type uranium deposits including Jabiluka, Ranger, Koongarra, Nabarlek and the small deposits of the South Alligator River Valley. A brief study of the basal portion of the formation showed it to consist entirely of mature conglomerates and quartzose sandstones. Analysis of the bedding types (planar cross beds, trough cross beds and parallel beds) and other sedimentary structures (mainly ripple marks and parting lineation) fit a braided alluvial plain model. A paleocurrent study utilizing about 400 measurements from nine localities located along the westward-facing 250 kilometer-long erosional escarpment of the Arnhem Land Plateau showed the dominant paleocurrent trend to be from west and northwest towards the east and southeast, with local divergence. The data and interpretation presented are relevant to the supergene model of uranium deposition at the unconformity, for they add to the suggestion that additional uranium deposits similar to Jabiluka Two may underlie the Kombolgie Formation eastward from the present escarpment

  16. Adolescent Hopefulness in Tanzania: Street Youth, Former Street Youth, and School Youth

    Science.gov (United States)

    Nalkur, Priya G.

    2009-01-01

    This study compares hope in street youth, former street youth, and school youth (aged 12-18) in Tanzania. Responding to Snyder's hope theory, the author argues that not only personal agency but also the stability of living context (street, shelter, home) shapes hopefulness. Employing qualitative and quantitative analyses, the author presents a…

  17. Personal and Familial Properties of Street Children--"Street Children: The Forgotten or Not Remembered Ones"

    Science.gov (United States)

    Özbas, Mehmet

    2015-01-01

    With this research it is aimed to determine the personal traits of Street Children depending on them and also the socio-economic variables of Street Children resulting from their families. For this main aim in the research process, it is provided to have communication directly with the parents of Street Children using one-to-one and face-to-face…

  18. Rockmagnetic correlation between Holocene cave sediments at the mountain and loess soil deposits in Piedmont Crimea (on example of the trap cave Emine-Bair-Khosar and archaeological site Biyuk-Karasu-XIX

    Directory of Open Access Journals (Sweden)

    Kseniia BONDAR

    2014-11-01

    Full Text Available Modern soils and paleosols, loess and uncemented aeolian caves sediments are carriers of a paleoclimatic signal (Evans, Heller, 2003. The saturation degree of a layer with humus material, depending on the temperature, correlates well with magnetic susceptibility and different types of magnetization of deposits (Tang et al., 2003, Bosak&Pruner, 2011.On the base of rockmagnetic measurements of soil-containing samples, collected from sections at Biyuk-Karasu-XIX (Piedmont Crimea and Emine-Bair-Khosar Cave (lower plateau of Chatyrdag mountain massive in Crimea (Ridush et al., 2013, correlation of sediments done in the context of common climate changes in the region during Holocene.The process of sediments accumulation in the sections covers roughly the same period. The loess soil section Biyuk-Karasu-XIX contains findings of hand shaped pottery and flintstones. The section structure has characteristic features of Holocene soil formation for which received a definite chronological anchor. The section of cave deposits in the Emine-Bair-Khosar Cave was dated by radiocarbon and paleomagnetic methods (Ridush et al., 2013. For saiga bone from the depth of 2.0 m radiocarbon (14C date 10,490 +/- 170 (Ki-13063 obtained. At -1.1 m deep the paleomagnetic excursion, dated 2.8 kyr BP, was recorded (Bondar, Ridush, 2010.Sediments of both sections are horizontally-layered. They contain darker units, which color is controlled by organic material, and lighter units of loess-like loam.Section Biyuk-Karasu-XIX consists of the following lithofacial units: 1, 2 - hlb2 – meadow alkaline chernozem, where unit 1 - horizon Hegl, unit 2 - horizon Hp, Pikgl, Pkgl; 3, 4 - hlb1 - the soil has features of grey or sod-calcareous soil forming, unit 3 combines horizons He and Eh, unit 4 – illuvial horizons Ihp and Pigl; 5 - pc-bg? - silty-sandy light loam. Lithofacial units are named according to “Stratigraphic scheme of Quaternary deposits of Ukraine” (Veklich et al

  19. Growth of superconducting Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} films by sedimentation deposition and liquid phase sintering and annealing technique

    Energy Technology Data Exchange (ETDEWEB)

    Manahan, R.L.C. [Condensed Matter Physics Laboratory, National Institute of Physics, University of the Philippines, Llamas Science Hall, Rm. 3122, E. Quirino Street, Diliman, Quezon City 1101 (Philippines)]. E-mail: rcmanahan@nip.upd.edu.ph; Sarmago, R.V. [Condensed Matter Physics Laboratory, National Institute of Physics, University of the Philippines, Llamas Science Hall, Rm. 3122, E. Quirino Street, Diliman, Quezon City 1101 (Philippines)

    2006-10-01

    We report on a technique of growing highly c-axis oriented Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi-2212) thick films on MgO substrate using a combined sedimentation-deposition and liquid phase sintering and annealing process. The temperature profiles employed partial melting followed by rapid cooling to temperature below the melting point. Scanning electron micrographs show that the films have a smooth surface. No evidence of grain boundaries on the film's surface can be seen. The critical temperatures of the samples range from {approx}67 K to {approx}81 K. This method presents a quick and easy preparation for high quality epitaxial Bi-2212 films.

  20. Lithogenic and biogenic particle deposition in an Antarctic coastal environment (Marian Cove, King George Island): Seasonal patterns from a sediment trap study

    Science.gov (United States)

    Khim, B. K.; Shim, J.; Yoon, H. I.; Kang, Y. C.; Jang, Y. H.

    2007-06-01

    Particulate suspended material was recovered over a 23-month period using two sediment traps deployed in shallow water (˜30 m deep) off the King Sejong Station located in Marian Cove of King George Island, West Antarctica. Variability in seasonal flux and geochemical characteristics of the sediment particles highlights seasonal patterns of sedimentation of both lithogenic (terrigenous) and biogenic particles in the coastal glaciomarine environment. All components including total mass flux, lithogenic particle flux and biogenic particle flux show distinct seasonal variation, with high recovery rates during the summer and low rates under winter fast ice. The major contributor to total mass flux is the lithogenic component, comprising from 88% during the summer months (about 21 g m -2 d -1) up to 97% during the winter season (about 2 g m -2 d -1). The lithogenic particle flux depends mainly on the amount of snow-melt (snow accumulation) delivered into the coastal region as well as on the resuspension of sedimentary materials. These fine-grained lithogenic particles are silt-to-clay sized, composed mostly of clay minerals weathered on King George Island. Biogenic particle flux is also seasonal. Winter flux is ˜0.2 g m -2 d -1, whereas the summer contribution increases more than tenfold, up to 2.6 g m -2 d -1. Different biogenic flux between the two summers indicates inter-annual variability to the spring-summer phytoplankton bloom. The maximum of lithogenic particle flux occurs over a short period of time, and follows the peak of biogenic particle flux, which lasts longer. The seasonal warming and sea-ice retreat result in change in seawater nutrient status and subsequent ice-edge phytoplankton production. Meanwhile, the meltwater input to Marian Cove from the coastal drainage in January to February plays a major role in transporting lithogenic particles into the shallow water environment, although the tidal currents may be the main agents of resuspension in this

  1. On the precision of sedimentation balance measurements

    NARCIS (Netherlands)

    Kranenburg, C.

    1991-01-01

    The settling velocities of fine sediments can be determined using a sedimentation balance essentially consisting of a settling tube at the bottom of which the weight of the sediment deposited is measured as a function of time. The distribution of settling velocities then is calculated from an

  2. Paleomagnetism and rock magnetism from sediments along a continental shelf-to-slope transect in the NW Barents Sea: Implications for geomagnetic and depositional changes during the past 15 thousand years

    Science.gov (United States)

    Caricchi, C.; Lucchi, R. G.; Sagnotti, L.; Macrì, P.; Morigi, C.; Melis, R.; Caffau, M.; Rebesco, M.; Hanebuth, T. J. J.

    2018-01-01

    Paleomagnetic and rock magnetic data were measured on glaciomarine silty-clay successions along an E-W sediment-core transect across the continental shelf and slope of the Kveithola paleo-ice stream system (south of Svalbard, north-western Barents Sea), representing a stratigraphic interval spanning the last deglaciation and the Holocene. The records indicate that magnetite is the main magnetic mineral and that magnetic minerals are distinctly less abundant on the shelf than at the continental slope. The paleomagnetic properties allow for the reconstruction of a well-defined characteristic remanent magnetization (ChRM) throughout the sedimentary successions. The stratigraphic trends of rock magnetic and paleomagnetic parameters are used for a shelf-slope core correlation and sediment facies analysis is applied for depositional processes reconstruction. The new paleomagnetic records compare to the PSV and RPI variation predicted for the core sites by a simulation using the global geomagnetic field variation models SHA.DIF.14k and CALS7K.2 and closest PSV and RPI regional stack curves. The elaborated dataset, corroborated by available 14C ages, provides a fundamental chronological framework to constrain the coupling of shelf-slope sedimentary processes and environmental changes in the NW Barents Sea region during and after deglaciation.

  3. RACE, CODE OF THE STREET, AND VIOLENT DELINQUENCY: A MULTILEVEL INVESTIGATION OF NEIGHBORHOOD STREET CULTURE AND INDIVIDUAL NORMS OF VIOLENCE*

    Science.gov (United States)

    Stewart, Eric A.; Simons, Ronald L.

    2011-01-01

    The study outlined in this article drew on Elijah Anderson’s (1999) code of the street perspective to examine the impact of neighborhood street culture on violent delinquency. Using data from more than 700 African American adolescents, we examined 1) whether neighborhood street culture predicts adolescent violence above and beyond an adolescent’s own street code values and 2) whether neighborhood street culture moderates individual-level street code values on adolescent violence. Consistent with Anderson’s hypotheses, neighborhood street culture significantly predicts violent delinquency independent of individual-level street code effects. Additionally, neighborhood street culture moderates individual-level street code values on violence in neighborhoods where the street culture is widespread. In particular, the effect of street code values on violence is enhanced in neighborhoods where the street culture is endorsed widely. PMID:21666759

  4. MAPCERN links to Google Street View

    CERN Multimedia

    Matilda Heron

    2015-01-01

    CERN’s online maps, MAPCERN, now have the added bonus of Google Street View, thanks to the new release of images of many CERN sites captured by Google.   New Street View images of CERN sites have been added to MAPCERN, see bottom-right-hand image in the screenshot above.   Google Street View, an integrated service of Google Maps introduced in 2007, links 360-degree panoramic photos into a virtual tour. CERN and Google began collaborating on this Street View project in 2010 and now these Street View images have been embedded into MAPCERN, accessible by clicking the “Street View” tab in MAPCERN’s bottom-right-hand window. If you need to locate a building at CERN, or plan an operation on some equipment, you can save time by using the Street View images to check out the area in advance. The CERN Meyrin site has been fully mapped, as well as the surfaces of the eight LHC points, BA2 and BA3. New Street View images of CERN, including the Pr...

  5. Factors affecting the partitioning of Cu, Zn and Pb in boulder coatings and stream sediments in the vicinity of a polymetallic sulfide deposit

    Science.gov (United States)

    Filipek, L.H.; Chao, T.T.; Carpenter, R.H.

    1981-01-01

    A sequential extraction scheme is utilized to determine the geochemical partitioning of Cu, Zn and Pb among hydrous Mn- and Fe-oxides, organics and residual crystalline silicates and oxides in the minus-80-mesh ( Fe-oxides > Mn-oxides; Zn, Mn-oxides {reversed tilde equals} organics > Fe-oxides; Pb, Fe-oxides > organics > Mn-oxides. In the sediments, organics are the most efficient scavengers of all three ore metals. These results emphasize the importance of organics as sinks for the ore metals, even in environments with high concentrations of Mn- and Fe-oxides. Of the ore metals, Zn appears to be the most mobile, and is partitioned most strongly into the coatings. However, anomaly contrast for hydromorphic Zn, normalized to the MnFe-oxide or organic content, is similar in sediments and coatings. Cu shows the highest anomaly on the boulder coatings, probably due to precipitation of a secondary Cu mineral. In contrast, detrital Pb in the pan concentrates shows a better anomaly than any hydromorphic Pb component. ?? 1981.

  6. Mineralogy and characterization of deposited particles of the aero sediments collected in the vicinity of power plants and the open pit coal mine: Kolubara (Serbia).

    Science.gov (United States)

    Cvetković, Željko; Logar, Mihovil; Rosić, Aleksandra

    2013-05-01

    In this paper, particular attention was paid to the presence of aerosol solid particles, which occurred mainly as a result of exploitation and coal combustion in the thermal power plants of the Kolubara basin. Not all of the particles created by this type of anthropogenic pollution have an equal impact on human health, but it largely depends on their size and shape. The mineralogical composition and particle size distribution in the samples of aero sediments were defined. The samples were collected close to the power plant and open pit coal mine, in the winter and summer period during the year 2007. The sampling was performed by using precipitators placed in eight locations within the territory of the Lazarevac municipality. In order to characterize the sedimentary particles, several methods were applied: microscopy, SEM-EDX and X-ray powder diffraction. The concentration of aero sediments was also determined during the test period. Variety in the mineralogical composition and particle size depends on the position of the measuring sites, geology of the locations, the annual period of collecting as well as possible interactions. By applying the mentioned methods, the presence of inhalational and respiratory particles variously distributed in the winter and in the summer period was established. The most common minerals are quartz and feldspar. The presence of gypsum, clay minerals, calcite and dolomite as secondary minerals was determined, as well as the participation of organic and inorganic amorphic matter. The presence of quartz as a toxic mineral has a particular impact on human health.

  7. Street as Sustainable City Structural Element

    Science.gov (United States)

    Leyzerova, A. V.; Bagina, E. J.

    2017-11-01

    Sustainability in architecture is nowadays of particular significance in the course of globalization and information density. The technospehere spontaneous development poses a threat to the sustainability of traditional urban forms where a street is one of the essential forming elements in the urban structure. The article proposes to consider formally compositional street features in relation to one of the traditional streets in the historic center of Ekaterinburg. The study examines the street-planning structure, the development of its skeleton elements, silhouette and fabric elevation characteristics as well as the scale characteristics and visual complexity of objects. The study provided architectural and artistic aspects of street sustainability, and limits of the appropriate scale and composition consistency under which the compatibility of alternative compositional forms existing at different times is possible.

  8. Cleaning up the Streets of Denver

    International Nuclear Information System (INIS)

    Stegen, R.L.; Wood, T.R.; Hackett, J.R.; Sogue, A.

    2006-01-01

    Between 1913 and 1924, several Denver area facilities extracted radium from carnotite ore mined from the Paradox basin region of Colorado. Tailings or abandoned ores from these facilities were apparently incorporated into asphalt used to pave approximately 7.2 kilometers (4.5 miles) of streets in Denver. A majority of the streets are located in residential areas. The radionuclides are bound within the asphalt matrix and pose minimal risk unless they are disturbed. The City and County of Denver (CCoD) is responsible for controlling repairs and maintenance on these impacted streets. Since 2002, the CCoD has embarked on a significant capital improvement project to remove the impacted asphalt for secure disposal followed by street reconstruction. To date, Parsons has removed approximately 55 percent of the impacted asphalt. This paper discusses the history of the Denver Radium Streets and summarizes on-going project efforts. (authors)

  9. The origin of dose distributions in fluvial sediments, and the prospect of dating single grains from fluvial deposits using optically stimulated luminescence

    CERN Document Server

    Olley, J M; Roberts, R G

    1999-01-01

    We examine the causes of the asymmetric distributions of dose observed from measurements of the optically stimulated luminescence emitted by small aliquots of fluvial quartz, and deduce that the asymmetry arises as a result of samples being composed of a mix of mainly well bleached grains with grains that were effectively unbleached at the time of deposition. We demonstrate that the shapes of the dose distributions can be used to assess the likelihood that aliquots consist only of grains that were well-bleached at the time of deposition. The more asymmetric the distribution, the greater the probability that the aliquots with the lowest dose most closely represent the true burial dose. Single grains with differing doses are present in each of the samples examined, and the population with the lowest dose gives an optical age consistent with the expected burial age. This result implies that the beta-dose heterogeneity in these deposits is small, and that the effects of micro-dosimetric variations on optical dati...

  10. Mapping Hydrothermal Alteration Zones at a Sediment-Hosted Gold Deposit - Goldstrike Mining District, Utah, Using Ground-Based Hyperspectral Imaging

    Science.gov (United States)

    Krupnik, D.; Khan, S.; Crockett, M.

    2017-12-01

    Understanding the origin, genesis, as well as depositional and structural mechanisms of gold mineralization as well as detailed mapping of gold-bearing mineral phases at centimeter scale can be useful for exploration. This work was conducted in the Goldstrike mining district near St. George, UT, a structurally complex region which contains Carlin-style disseminated gold deposits in permeable sedimentary layers near high-angle fault zones. These fault zones are likely a conduit for gold-bearing hydrothermal fluids, are silicified, and are frequently gold-bearing. Alteration patterns are complex, difficult to distinguish visually, composed of several phases, and vary significantly over centimeter to meter scale distances. This makes identifying and quantifying the extent of the target zones costly, time consuming, and discontinuous with traditional geochemical methods. A ground-based hyperspectral scanning system with sensors collecting data in the Visible Near Infrared (VNIR) and Short-Wave Infrared (SWIR) portions of the electromagnetic spectrum are utilized for close-range outcrop scanning. Scans were taken of vertical exposures of both gold-bearing and barren silicified rocks (jasperoids), with the intent to produce images which delineate and quantify the extent of each phase of alteration, in combination with discrete geochemical data. This ongoing study produces mineralogical maps of surface minerals at centimeter scale, with the intent of mapping original and alteration minerals. This efficient method of outcrop characterization increases our understanding of fluid flow and alteration of economic deposits.

  11. Engineering Multifunctional Living Paints: Thin, Convectively-Assembled Biocomposite Coatings of Live Cells and Colloidal Latex Particles Deposited by Continuous Convective-Sedimentation Assembly

    Science.gov (United States)

    Jenkins, Jessica Shawn

    Advanced composite materials could be revolutionized by the development of methods to incorporate living cells into functional materials and devices. This could be accomplished by continuously and rapidly depositing thin ordered arrays of adhesive colloidal latex particles and live cells that maintain stability and preserve microbial reactivity. Convective assembly is one method of rapidly assembling colloidal particles into thin (advantages over thicker randomly ordered composites, including enhanced cell stability and increased reactivity through minimized diffusion resistance to nutrients and reduced light scattering. This method can be used to precisely deposit live bacteria, cyanobacteria, yeast, and algae into biocomposite coatings, forming reactive biosensors, photoabsorbers, or advanced biocatalysts. This dissertation developed new continuous deposition and coating characterization methods for fabricating and characterizing 90 hours) photohydrogen production under anoxygenic conditions. Nutrient reduction slows cell division, minimizing coating outgrowth, and promotes photohydrogen generation, improving coating reactivity. Scanning electron microscopy of microstructure revealed how coating reactivity can be controlled by the size and distribution of the nanopores in the biocomposite layers. Variations in colloid microsphere size and suspension composition do not affect coating reactivity, but both parameters alter coating microstructure. Porous paper coated with thin coatings of colloidal particles and cells to enable coatings to be used in a gas-phase without dehydration may offer higher volumetric productivity for hydrogen production. Future work should focus on optimization of cell density, light intensity, media cycling, and acetate concentration.

  12. Thermal Comfort Assessment in The Open Space in Bandung Case Study Dago Street and Riau Street

    Science.gov (United States)

    Sugangga, M.; Janesonia, K. I.; Illiyin, D. F.; Donny Koerniawan, M.

    2018-05-01

    Bandung’s temperature has been higher since last years. This phenomenon affects the level of thermal comfort in open space. One indicator that determines the thermal comfort level is the type of activity performed by the open space user. Riau Street and Dago Street are corridors that are often used by the people for strolling, jogging, shopping. Dago Street has special event every Sunday namely car free day. Both corridors have different orientation; Dago Street is North to South corridor while Riau Street’s is West to East. The goal of the study is to compare people’s perception of thermal comfort in both corridors. This research uses two methods, namely qualitative method and quantitative method. Based on the results of qualitative analysis found that the thermal conditions in Dago Street more comfortable than the Riau Street. The result of quantitative analysis found that the average PET (thermal comfort indices) value of Dago Street was at 27.5 °C PET and Riau Street 28.6 °C PET. Dago Street is considered more convenient because it has a lower PET value than Riau Street. The people perception of thermal comfort is very important to start the steps for designing the orientation of street in urban design.

  13. Road and Street Centerlines, Street-The data set is a line feature consisting of 13948 line segments representing streets. It was created to maintain the location of city and county based streets., Published in 1989, Davis County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Road and Street Centerlines dataset current as of 1989. Street-The data set is a line feature consisting of 13948 line segments representing streets. It was created...

  14. Uranium deposits in Africa

    International Nuclear Information System (INIS)

    Wilpolt, R.H.; Simov, S.D.

    1979-01-01

    Africa is not only known for its spectacular diamond, gold, copper, chromium, platinum and phosphorus deposits but also for its uranium deposits. At least two uranium provinces can be distinguished - the southern, with the equatorial sub-province; and the south Saharan province. Uranium deposits are distributed either in cratons or in mobile belts, the first of sandstone and quartz-pebble conglomerate type, while those located in mobile belts are predominantly of vein and similar (disseminated) type. Uranium deposits occur within Precambrian rocks or in younger platform sediments, but close to the exposed Precambrian basement. The Proterozoic host rocks consist of sediments, metamorphics or granitoids. In contrast to Phanerozoic continental uranium-bearing sediments, those in the Precambrian are in marginal marine facies but they do contain organic material. The geology of Africa is briefly reviewed with the emphasis on those features which might control the distribution of uranium. The evolution of the African Platform is considered as a progressive reduction of its craton area which has been affected by three major Precambrian tectonic events. A short survey on the geology of known uranium deposits is made. However, some deposits and occurrences for which little published material is available are treated in more detail. (author)

  15. An integrated study of geochemistry and mineralogy of the Upper Tukau Formation, Borneo Island (East Malaysia): Sediment provenance, depositional setting and tectonic implications

    Science.gov (United States)

    Nagarajan, Ramasamy; Roy, Priyadarsi D.; Kessler, Franz L.; Jong, John; Dayong, Vivian; Jonathan, M. P.

    2017-08-01

    An integrated study using bulk chemical composition, mineralogy and mineral chemistry of sedimentary rocks from the Tukau Formation of Borneo Island (Sarawak, Malaysia) is presented in order to understand the depositional and tectonic settings during the Neogene. Sedimentary rocks are chemically classified as shale, wacke, arkose, litharenite and quartz arenite and consist of quartz, illite, feldspar, rutile and anatase, zircon, tourmaline, chromite and monazite. All of them are highly matured and were derived from a moderate to intensively weathered source. Bulk and mineral chemistries suggest that these rocks were recycled from sedimentary to metasedimentary source regions with some input from granitoids and mafic-ultramafic rocks. The chondrite normalized REE signature indicates the presence of felsic rocks in the source region. Zircon geochronology shows that the samples were of Cretaceous and Triassic age. Comparable ages of zircon from the Tukau Formation sedimentary rocks, granitoids of the Schwaner Mountains (southern Borneo) and Tin Belt of the Malaysia Peninsular suggest that the principal provenance for the Rajang Group were further uplifted and eroded during the Neogene. Additionally, presence of chromian spinels and their chemistry indicate a minor influence of mafic and ultramafic rocks present in the Rajang Group. From a tectonic standpoint, the Tukau Formation sedimentary rocks were deposited in a passive margin with passive collisional and rift settings. Our key geochemical observation on tectonic setting is comparable to the regional geological setting of northwestern Borneo as described in the literature.

  16. Geological factors of deposit formation

    International Nuclear Information System (INIS)

    Grushevoj, G.V.

    1980-01-01

    Geologic factors of hydrogenic uranium deposit formation are considered. Structural, formation and lithological-facies factors of deposit formation, connected with zones of stratal oxidation, are characterized. Peculiarities of deposit localization, connected with orogenic structures of Mesozoic and lenozoic age, are described. It is noted that deposits of anagenous group are widely spread in Paleozoic formations, infiltration uranium deposits are localized mainly in Cenozoic sediments, while uranium mineralization both anagenous and infiltration groups are widely developed in Mesozoic sediments. Anagenous deposits were formed in non-oxygen situation, their age varies from 200 to 55 mln years. Infiltration deposit formation is determined by asymmetric oxidation zonation, their age varies from 10 - 40 mln years to dozens of thousand years [ru

  17. Street children and political violence: a socio-demographic analysis of street children in Rwanda.

    Science.gov (United States)

    Veale, Angela; Donà, Giorgia

    2003-03-01

    The aims were: (1) to examine the profile of African street children and to assess the link between street children in Africa and political violence; (2) to undertake a systematic examination of causal factors of street children in postgenocide Rwanda; and (3) to situate this analysis in the context of the socio-cultural and political impact of the genocide on Rwandan communities. Observational mapping examined the profile and activities of Rwandan street children. Structured interviews were carried out with 290 children in four regional towns to obtain information on socio-demographic, familial, educational background, causal factors surrounding street life involvement, psychological well-being, and relationship to the street. Focus group discussions and key informant interviews examined the relationship between street children and the broader Rwandan society. Street children in Rwanda were predominantly adolescent boys, almost half of whom were homeless (42%), with a high proportion of orphaned children or children who had lost at least one parent. Two variables predicted homelessness: child's guardian and reason for being in street. Qualitative accounts of children conveyed the impact of death of family members, repatriation, imprisonment of parents, and poverty on their lives. The analysis highlighted the need for community based support for children in alternative guardianship care and for policies to support the reintegration of male youths in postconflict welfare strategies as prevention strategies for street migration.

  18. Geologic setting, sedimentary architecture, and paragenesis of the Mesoproterozoic sediment-hosted Sheep Creek Cu-Co-Ag deposit, Helena embayment, Montana

    Science.gov (United States)

    Graham, Garth; Hitzman, Murray W.; Zieg, Jerry

    2012-01-01

    The northern margin of the Helena Embayment contains extensive syngenetic to diagenetic massive pyrite horizons that extend over 25 km along the Volcano Valley-Buttress fault zone and extend up to 8 km basinward (south) within the Mesoproterozoic Newland Formation. The Sheep Creek Cu-Co deposit occurs within a structural block along a bend in the fault system, where replacement-style chalcopyrite mineralization is spatially associated mostly with the two stratigraphically lowest massive pyrite zones. These mineralized pyritic horizons are intercalated with debris flows derived from synsedimentary movement along the Volcano Valley-Buttress fault zone. Cominco American Inc. delineated a geologic resource of 4.5 Mt at 2.5% Cu and 0.1% Co in the upper sulfide zone and 4 Mt at 4% Cu within the lower sulfide zone. More recently, Tintina Resources Inc. has delineated an inferred resource of 8.48 Mt at 2.96% Cu, 0.12% Co, and 16.4 g/t Ag in the upper sulfide zone. The more intact upper sulfide zone displays significant thickness variations along strike thought to represent formation in at least three separate subbasins. The largest accumulation of mineralized sulfide in the upper zone occurs as an N-S–trending body that thickens southward from the generally E trending Volcano Valley Fault and probably occupies a paleograben controlled by normal faults in the hanging wall of the Volcano Valley Fault. Early microcrystalline to framboidal pyrite was accompanied by abundant and local barite deposition in the upper and lower sulfide zones, respectively. The sulfide bodies underwent intense (lower sulfide zone) to localized (upper sulfide zone) recrystallization and overprinting by coarser-grained pyrite and minor marcasite that is intergrown with and replaces dolomite. Silicification and paragenetically late chalcopyrite, along with minor tennantite in the upper sulfide zone, replaces fine-grained pyrite, barite, and carbonate. The restriction of chalcopyrite to inferred

  19. Cyclic Sediment Trading Between Channel and River Bed Sediments

    Science.gov (United States)

    Haddadchi, A.

    2015-12-01

    Much of the previous work on sediment tracing has focused on determining either the initial sources of the sediment (soils derive from a particular rock type) or the erosion processes generating the sediment. However, alluvial stores can be both a source and sink for sediment transported by streams. Here geochemical and fallout radionuclide tracing of river-bed and alluvial sediments are used to determine the role of secondary sources, sediment stores, as potential sources of sediment leaving Emu Creek catchment, southeastern Queensland, Australia. Activity concentrations of 137Cs on the river sediments are consistent with channel erosion being the dominant source at all sites sampled along the river. To characterise the deposition and remobilisation cycles in the catchment, a novel geochemical tracing approach was used. Successive pockets of alluvium were treated as discrete sink terms within geochemical mixing models and their source contributions compared with those of river bed sediments collected adjacent to each alluvial pocket. Three different size fractions were examined; silts and clays (banks indicates a high degree of 'trading' between the fluvial space and the alluvial space. Hence, management works aimed at primarily reducing the supply of sediments to the outlet of Emu Creek should focus on rehabilitation of channel banks in the lower catchment.

  20. Hygiene practices among street food vendors

    African Journals Online (AJOL)

    User

    giene regulations to keep street food save for consumers. Journal of Medical ... UDS Publishers Limited All Right Reserved 2026-6294 ... authorities to enforce food safety regulations, unlike .... (50%) school food vendors sampled in Konongo.

  1. Capturing the benefits of complete streets.

    Science.gov (United States)

    2015-12-01

    Anecdotal information indicates that private investment and property value increases are associated : with featured Complete Streets projects. However, to date, little research has been done to confirm : these benefits. Much of the relevant literatur...

  2. Pühendusega isadele - Baker Street

    Index Scriptorium Estoniae

    2009-01-01

    Üritusest 7. novembril Kuressaares Arensburg lounge-restoranis Muusa toimuvast isadepäevahõngulisest üritusest, esinevad Virgo Veldi & Band kavaga "Baker Street", erikülalisena Villu Veski. Saksofonistist Virgo Veldist

  3. Hiding in Plain Sight: Street artists online

    Directory of Open Access Journals (Sweden)

    Kim Barbour

    2013-10-01

    Full Text Available Identity and privacy concerns related to social media are the subject of widespread academic enquiry and mass media reporting. Although in most circumstances academic research tends to present identity play and online self­presentation as positive, media reporting in Australia makes much of the risks of identity theft, privacy breaches and online predators. This research explores the phenomenological experience of creating an online persona, focusing particularly on street artists. For street artists, the threat of unwanted exposure has to be balanced with the positive implications of sharing their creative work outside its geographical and temporal constraints. I argue that street artists use complex persona­creation strategies in order to both protect and promote themselves. The two street artists discussed in this article experience their engagement with social media and digital networks in ways that offer new insight into the opportunities and problems associated with the presentation of a persona online.

  4. Modelling Pollutant Dispersion in a Street Network

    Science.gov (United States)

    Salem, N. Ben; Garbero, V.; Salizzoni, P.; Lamaison, G.; Soulhac, L.

    2015-04-01

    This study constitutes a further step in the analysis of the performances of a street network model to simulate atmospheric pollutant dispersion in urban areas. The model, named SIRANE, is based on the decomposition of the urban atmosphere into two sub-domains: the urban boundary layer, whose dynamics is assumed to be well established, and the urban canopy, represented as a series of interconnected boxes. Parametric laws govern the mass exchanges between the boxes under the assumption that the pollutant dispersion within the canopy can be fully simulated by modelling three main bulk transfer phenomena: channelling along street axes, transfers at street intersections, and vertical exchange between street canyons and the overlying atmosphere. Here, we aim to evaluate the reliability of the parametrizations adopted to simulate these phenomena, by focusing on their possible dependence on the external wind direction. To this end, we test the model against concentration measurements within an idealized urban district whose geometrical layout closely matches the street network represented in SIRANE. The analysis is performed for an urban array with a fixed geometry and a varying wind incidence angle. The results show that the model provides generally good results with the reference parametrizations adopted in SIRANE and that its performances are quite robust for a wide range of the model parameters. This proves the reliability of the street network approach in simulating pollutant dispersion in densely built city districts. The results also show that the model performances may be improved by considering a dependence of the wind fluctuations at street intersections and of the vertical exchange velocity on the direction of the incident wind. This opens the way for further investigations to clarify the dependence of these parameters on wind direction and street aspect ratios.

  5. Street-Level Bureaucrats as Individual Policymakers:

    DEFF Research Database (Denmark)

    Baviskar, Siddhartha; Winter, Søren

    2016-01-01

    Lipsky (1980) pointed out that street-level bureaucrats (SLBs) are important policymakers due to the discretion they exercise and argued from a structural perspective that these workers manifest relatively similar coping behaviors owing to their shared working conditions, characterized by chronic......Lipsky (1980) pointed out that street-level bureaucrats (SLBs) are important policymakers due to the discretion they exercise and argued from a structural perspective that these workers manifest relatively similar coping behaviors owing to their shared working conditions, characterized...

  6. Solar charge controller in solar street light

    OpenAIRE

    Dong, Haibo

    2014-01-01

    Recently, with the rapid development of scientific technology, the conventional energy cannot meet the requirement of human beings. People are looking for the utilization of renew energy. Solar en-ergy as a new clean energy has attract the eyes of people. The applications of solar energy are popular to human society. Solar street light is a good example. This thesis will focus on a deeper research of the popular and ubiquitous solar street light in China. However, solar charge controll...

  7. OpenStreetMap over WMS

    Directory of Open Access Journals (Sweden)

    Přemysl Vohnout

    2010-02-01

    Full Text Available This paper discuss the issues which we faced, while preparing WMS server with OpenStreetMap data of whole Europe. This article is divided into three sections. First is about mandatory applications which are required for working WMS service with OpenStreetMap data. Second is focused on tuning up PostgreSQL. Third is focused on rendering time improvement of layers.

  8. MAINTENANCE OF THE CARPARK AND STREET LIGHTING

    CERN Multimedia

    ST-FM Group

    2002-01-01

    The ST Division informs you that the control and maintenance of the carpark and street lighting will be carried out during the next few weeks. These lightings work normally by photocells but during these tests they will be turned on zone by zone during the day. So we ask the users not to be surprised to see the street lighting on during the day and thank them for their comprehension. ST-FM Group

  9. [Sharing and distrusting: street merchants' view of children in street situations].

    Science.gov (United States)

    Sánchez-Suárez, Diana M; Giraldo-Puerta, Alexandra; Giraldo-Pineda, Álvaro; Forero-Pulido, Constanza

    2016-06-01

    Objective To understand the meanings, through the description of experiences that street merchants have of their interactions with children in a street situation in downtown of Medellin in 2013. Methodology Qualitative investigation with ethnographic approach. Observations were made in the zone at different times of the day. Twelve interviews with street merchants were held in their work places. Records were kept in a field journal. Results The street merchants and children in street situations share the same space. Both groups try to survive and their relationship is mediated by the trust-distrust that is established between them. The coexistence generates ambivalent feelings. For the street merchants, children in street situations are the result of abandonment by the family, the state and society. They live in a hard world in which they are exposed to a series of risks that they must face. Conclusion The interaction between street merchants and children in street situations is good to the extent that conflicts are avoided, establishing norms of coexistence. The element that determines this relationship is trust-distrust. In trust, strong affective ties are generated, considering each other family. Distrust generates a preventative attitude.

  10. Universal design characteristic on themed streets

    Science.gov (United States)

    Harsritanto, Bangun IR; Indriastjario; Wijayanti

    2017-12-01

    People around the world can access the streets to fulfil their daily activities regardless of their gender, age, and abilities. The streetscape is an urban public space which is built to facilitate the basic needs of people as social being. The themed street is an urban streetscape designed and built in detail with a theme or special purpose in an of urban development process. Universal design facilitates the full range of human diversity as physical appearance, perception, cognitive abilities, sizes, and shapes. By designing for the diversity, the specialized streets become more functional and user-friendly. The purpose of this study is to examine several design characteristics of themed streets in several countries from three different continents using universal design principles for giving proper directions to develop more user-friendly streets. Literature review and case study were used as research methods. The literature review was extracted and compiled from manuscripts, streetscape design books, and from universal design principles. Furthermore, the constructed theory were used to examine the case studies of themed streets. The findings indicated that themed streets’ character design were strongly influenced by local cultural aspect even though the basic guidelines were universal design principles; the resumed design direction can be suggested universal along with the richness of local aspects.

  11. Designing safe and inclusive streets in India | CRDI - Centre de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    17 nov. 2016 ... Safe streets play a crucial role in enabling livelihoods, mobility, and access to services. In fast-growing Indian cities such as Ahmedabad, streets are also the site of conflict. With incomes and vehicle ownership on the rise, traffic has replaced people as the central point of street design. Vehicle-focused street ...

  12. StreetMekka - Ledelse af Københavns nye streetkulturhus

    OpenAIRE

    Gjelstrup, Mikkel

    2009-01-01

    Street culture is spreading out through the streets of Denmark and in the summer of 2009 the City of Copenhagen will open up an indoor street culture facility called StreetMekka. Moving street culture from its natural concrete habitat to a communal facility presents challenges. The City of Copenhagen has made official guideline for the StreetMekka facility to follow, but the free and self organized street culture is not an easy thing to keep within guidelines. This master thesis discusses fro...

  13. Public Reactions to New Street Tree Planting

    Directory of Open Access Journals (Sweden)

    Ruth A. Rae

    2010-01-01

    Full Text Available MillionTreesNYC, which has the goal of planting one million trees in New York City by 2017, is intended to make New York City a greener, more sustainable city and is part of the Mayor’s comprehensive long term strategic plan, PlaNYC. Through planting a tree at every suitable sidewalk location in the city, the City of New York is transforming blocks and communities, and providing a variety of environmental, social and aesthetic benefits. This article examines the large scale municipal planting of new street trees and the reaction by some of the pubic to this planting.Trees offer benefits to the city overall, but the public may not understand these benefits or the street tree planting process. Between 2007 and 2009, the Department of Parks & Recreation planted 53,235 new street trees, and received 4,108 items of correspondence from the public. The majority of this correspondence consisted of public comments about the City’s new street tree planting policies and processes including placement objections, maintenance concerns, reports of resultant damage from tree planting operations, requests for new street trees and reports of tree conditions.This study describes the operational policies that guide New York City's municipal street tree planting, and results of content and spatial analysis of the correspondence. Qualitative analysis of the correspondence revealed the public perceptions and concerns related to the MillionTreesNYC program. Spatial analysis explored the relationship between the planting locations of new street trees and the locations of the citizen correspondence.Public reactions to this large scale municipal planting are related to the dual public and private nature of the sidewalk, issues of territoriality, responsibility, aesthetics and place attachment. Correspondence volume was associated with the scale of the new street tree block planting program, and the effectiveness of NYC’s 311 Customer Service Center. The discussion

  14. Life Cores: A Sci-Art Collaboration Between a Snow/Ice Researcher, an Artist/Educator, Students, and Street Road Artists Space

    Science.gov (United States)

    Dooley, J.; Courville, Z.; Artinian, E.

    2016-12-01

    BackgroundStreet Road Artists Space Summer 2015 show was Sailing Stones. Works presented scenarios on tension between transience and permanence, highlighting cultural constructs imposed onto landscape and place. Dooley's installation, CryoZen Garden, operated as visual metaphor, modeling cryospheric processes and explored effects of melting polar ice caps on a warming world. A grant from Pennsylvania Partners in the Arts, with a focus on sharing contemporary works which were participatory, conceptual, and polar science research-based, allowed for a new project to engage community members, particularly students.MethodsIn this project students were introduced to the work of Dooley, artist/educator and Courville, snow/ice researcher. Students created `Life Cores', a take on ice and sediment coring scientists use as evidence of Earth's atmospheric and geologic changes. Students were given plastic tubes 2' long and 2" in diameter and were asked to add a daily layer of materials taken from everyday life, for a one month period. Students chose materials important to them personally, and kept journals, reflecting on items' significance, and/or relationship to life and world events. After creation of the Life Cores, Courville and Dooley visited students, shared their work on polar research, what it's like to live and work on ice, and ways science and art can intertwine to create better understanding of climate change issues. Students used core logging sheets to make observations of each others' life cores, noting layer colors, textures and deposition rates as some of the characteristics researchers use in ice and sediment core interpretation. Students' work was exhibited at Street Road and will remain on Street Road's website. Courville and Dooley presented to the general public during the opening. ConclusionsParticipants were better able to answer the question, How do we know what we know from coring? by relating the science to something that is known and personal, such as

  15. Soils and organic sediments

    International Nuclear Information System (INIS)

    Head, M.J.

    1999-01-01

    The organic component of soils is basically made up of substances of an individual nature (fats, waxes, resins, proteins, tannic substances, and many others), and humic substances (Kononova, 1966). These are complex polymers formed from breakdown products of the chemical and biological degradation of plant and animal residues. They are dark coloured, acidic, predominantly aromatic compounds ranging in molecular weight from less than one thousand to tens of thousands (Schnitzer, 1977). They can be partitioned into three main fractions:(i) Humic acid, which is soluble in dilute alkaline solution, but can be precipitated by acidification of the alkaline extract.(ii) Fulvic acid, which is soluble in alkaline solution, but is also soluble on acidification.(iii) Humin that cannot be extracted from the soil or sediment by dilute acid or alkaline solutions. It has mostly been assumed that the humic and fulvic acid components of the soil are part of the mobile, or 'active' component, and the humin component is part of the 'passive' component. Other types of organic sediments are likely to contain chemical breakdown products of plant material, plant fragments and material brought in from outside sources. The outside material can be contemporaneous with sediment deposition, can be older material, or younger material incorporated into the sediment long after deposition. Recognition of 'foreign' material is essential for dating, but is not an easy task. Examples of separation techniques for humic and non humic components are evaluated for their efficiency

  16. A Study on Evaluation for Street Space using AHP Method

    OpenAIRE

    小塚, みすず; 許, 彦; 川本, 義海; 本多, 義明

    2004-01-01

    Street space is an important public area which forms the framework of city space. In addition, from the view of the traffic functions, street space also plays a role to support people's activities performed in city. This paper examines the evaluations of street space among the cities of Fukui (Japan), Toyota (Japan) and Suzhou (China). Therefore, a questionnaire has been carried out and actual conditions of street space are grasped. In addition street functions were evaluated with the AHP met...

  17. Modelling sewer sediment deposition, erosion, and transport processes to predict acute influent and reduce combined sewer overflows and CO(2) emissions.

    Science.gov (United States)

    Mouri, Goro; Oki, Taikan

    2010-01-01

    Understanding of solids deposition, erosion, and transport processes in sewer systems has improved considerably in the past decade. This has provided guidance for controlling sewer solids and associated acute pollutants to protect the environment and improve the operation of wastewater systems. Although measures to decrease combined sewer overflow (CSO) events have reduced the amount of discharged pollution, overflows continue to occur during rainy weather in combined sewer systems. The solution lies in the amount of water allotted to various processes in an effluent treatment system, in impact evaluation of water quality and prediction technology, and in stressing the importance of developing a control technology. Extremely contaminated inflow has been a serious research subject, especially in connection with the influence of rainy weather on nitrogen and organic matter removal efficiency in wastewater treatment plants (WWTP). An intensive investigation of an extremely polluted inflow load to WWTP during rainy weather was conducted in the city of Matsuyama, the region used for the present research on total suspended solid (TSS) concentration. Since the inflow during rainy weather can be as much as 400 times that in dry weather, almost all sewers are unsettled and overflowing when a rain event is more than moderate. Another concern is the energy consumed by wastewater treatment; this problem has become important from the viewpoint of reducing CO(2) emissions and overall costs. Therefore, while establishing a prediction technology for the inflow water quality characteristics of a sewage disposal plant is an important priority, the development of a management/control method for an effluent treatment system that minimises energy consumption and CO(2) emissions due to water disposal is also a pressing research topic with regards to the quality of treated water. The procedure to improve water quality must make use of not only water quality and biotic criteria, but also

  18. Road and Street Centerlines - COUNTY_STREET_CENTERLINES_IDHS_IN: Street Centerlines Maintained by County Agencies in Indiana (Indiana Department of Homeland Security, Line Shapefile)

    Data.gov (United States)

    NSGIC State | GIS Inventory — COUNTY_STREET_CENTERLINES_IDHS_IN is a line feature class that contains street centerlines maintained by county agencies in Indiana, provided by personnel of Indiana...

  19. The social world of street children : street children's peer friendship, group life and subculture in Addis Ababa, Ethiopia

    OpenAIRE

    Fikre, Kaleab

    2016-01-01

    This study attempts to explore the street children’s social world, focusing on their peer friendship, group life, and street subculture in Addis Ababa, Ethiopia. The study shows how street children’s peer friendship, street group, and subculture are part and parcel of children’s quest for survival in the street in the absence of guardians conventionally considered as responsible for the provision and protection of children. The main perspective of the study is grounded in the p...

  20. Street Children as M arginal People: The Relationship between Life History and Social Networks on the Street

    OpenAIRE

    SUCHARITKUL, Juthathip

    2007-01-01

    This paper assumes that street children are victims of socioeconomic development policy. As a consequence of the street life experience, children are labeled as street children by society and their way of their life is different from ordinary children, thus pushing them to become marginalized people. The purpose of this paper is to examine the Street Children phenomenon, and especially to study the relationship between their life history and personal networks on the street. The focus is to...

  1. Generative Street Addresses from Satellite Imagery

    Directory of Open Access Journals (Sweden)

    İlke Demir

    2018-03-01

    Full Text Available We describe our automatic generative algorithm to create street addresses from satellite images by learning and labeling roads, regions, and address cells. Currently, 75% of the world’s roads lack adequate street addressing systems. Recent geocoding initiatives tend to convert pure latitude and longitude information into a memorable form for unknown areas. However, settlements are identified by streets, and such addressing schemes are not coherent with the road topology. Instead, we propose a generative address design that maps the globe in accordance with streets. Our algorithm starts with extracting roads from satellite imagery by utilizing deep learning. Then, it uniquely labels the regions, roads, and structures using some graph- and proximity-based algorithms. We also extend our addressing scheme to (i cover inaccessible areas following similar design principles; (ii be inclusive and flexible for changes on the ground; and (iii lead as a pioneer for a unified street-based global geodatabase. We present our results on an example of a developed city and multiple undeveloped cities. We also compare productivity on the basis of current ad hoc and new complete addresses. We conclude by contrasting our generative addresses to current industrial and open solutions.

  2. Stratigraphic implications of uranium deposits

    International Nuclear Information System (INIS)

    Langford, F.F.

    1980-01-01

    One of the most consistent characteristics of economic uranium deposits is their restricted stratigraphic distribution. Uraninite deposited with direct igneous affiliation contains thorium, whereas chemical precipitates in sedimentary rocks are characterized by thorium-free primary uranium minerals with vanadium and selenium. In marine sediments, these minerals form low-grade disseminations; but in terrestrial sediments, chiefly fluvial sandstones, the concentration of uranium varies widely, with the high-grade portions constituting ore. Pitchblende vein deposits not only exhibit the same chemical characteristics as the Colorado-type sandstone deposits, but they have a stratigraphically consistent position at unconformities covered by fluvial sandstones. If deposits in such diverse situations have critical features in common, they are likely to have had many features of their origin in common. Thus, vein deposits in Saskatchewan and Australia may have analogues in areas that contain Colorado-type sandstone deposits. In New Mexico, the presence of continental sandstones with peneconformable uranium deposits should also indicate good prospecting ground for unconformity-type vein deposits. All unconformities within the periods of continental deposition ranging from Permian to Cretaceous should have uranium potential. Some situations, such as the onlap of the Abo Formation onto Precambrian basement in the Zuni Mountains, may be directly comparable to Saskatchewan deposition. However, uranium occurrences in the upper part of the Entrada Sandstone suggest that unconformities underlain by sedimentary rocks may also be exploration targets

  3. Notes on LED Installations in Street Illumination

    Directory of Open Access Journals (Sweden)

    Elisabeta Spunei

    2014-09-01

    Full Text Available The paper presents a study made on choosing LED street lighting installations, such that the quality requirements for exterior artificial lighting are fulfilled. We analyze two types of LED street lighting installations from a technical point of view, together with lighting level and brightness values obtained during the measurements. Following on the field measurements, the lighting quality parameters are calculated, and, for the lighting installation with the best performance, optimal mounting suggestions are made. The optimal quality parameters are calculated by simulations using the Dialux software. The same software and the same light sources we also compute an optimal street lighting by determining the size of the installation that provides the best lighting parameter values.

  4. Lead in Glasgow street dirt and soil

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J G [Univ. of Glasgow; Lyon, T D.B.

    1977-07-01

    The levels of lead in city street dirt and in soil from various locations in Glasgow were investigated during spring 1976. Lead concentrations in street dirt ranged from 150 to 2300 ppM, mean 960 ppM, and were significantly elevated with respect to the observed ''natural'' level of 78 ppM. Lead derived from anti-knock compounds in petrol and introduced to the environment via automobile exhausts was clearly implicated as the main source of lead pollution in a series of soil lead measurements at the centre and periphery of eight Glasgow parks. Various chemical leaching techniques were employed and compared. Less than 5 percent of street dirt and soil lead was found to be associated with the organic phase.

  5. Sediment exchange between groin fields and main-stream

    Science.gov (United States)

    Qin, Jie; Zhong, Deyu; Wu, Teng; Wu, Lingli

    2017-10-01

    Sediment exchange between groin fields and the main-stream influences the transport and distribution of polluted sediment that represents a hazard for rivers and neighboring floodplains. Despite its practical significance, little research has been done on the sediment exchange process itself, and existing studies used to estimate the sediment exchange by morphological change. The sediment exchange process, however, differs from morphological variation and includes two behaviors: the entrance of main-stream sediment into groin fields and the movement of groin field sediment out of groin fields. Therefore, this study aims at examining this exchange process and exploring the mechanisms of different exchange phenomena. Experiments were conducted in a mobile-bed laboratory flume by using a novel experimental method that successfully separates the movement of groin fields sediment from that of main-stream sediment. In addition to traditional measurements, such as measurements of morphological changes, surface flow velocities, and bed-form propagation, the deposition of main-stream sediment in groin fields is measured in detail. The results demonstrate that morphological change cannot reflect the sediment exchange process. The deposition of main-stream sediment in groin fields is determined by the dynamics of sediment movement, in which bedload- and suspended-sediment-dominated processes exhibit different deposition patterns. The movement of groin field sediment out of groin fields is determined mainly by local scouring around groins.

  6. Risk behaviour of street children in Colombo.

    Science.gov (United States)

    Senaratna, B C V; Wijewardana, B V N

    2012-09-01

    Sri Lankan street children live in insecure and disadvantaged environments and have disrupted and poorly functioning families resulting in their poor socialisation. In this backdrop they are at high risk of adopting delinquent and antisocial behaviour and becoming victims of abuse. Despite recognition of this as a social problem, an in-depth exploration of their behaviour and its correlates has not been attempted. To describe risk behaviour among street children in Colombo city and the determinants of such behaviour. A cross sectional qualitative study in Colombo Fort, Pettah, Slave Island, and Maradana areas was conducted using focus group discussions (FGDs) with street children and semi-structured interviews (SSIs) with street children and key informants in their environment. Data generated were used to profile 283 children identified through referral sampling. An observation study was conducted to validate data generated through FGDs and SSIs. Semi-structured questionnaires, a moderator guide, an interviewer-administered questionnaire, and an observational checklist were used for SSIs, FGDs, profiling, and observational study, respectively. Majority of street children were boys and were aged 14 years or less. Nearly 18% lived alone without a guardian. Two thirds had never enrolled in a school. Many children were used for begging, neglecting their health vulnerabilities. Occupational risk behaviour included heavy manual labour, transportation and sale of illicit alcohol and narcotics, robbing/pick-pocketing, commercial sex work, and pimping. Recreational risk behaviour included abuse of alcohol/narcotics, smoking, sexual promiscuity, and patronising commercial sex workers. Increased awareness and strategies are required to minimise threats to street children and society.

  7. Street children of India -- a glimpse.

    Science.gov (United States)

    Nigam, S

    1994-01-01

    In India, 90% of street children are working children with regular family ties who live with their families, but are on the streets due to poverty and their parents' unemployment. The remaining 10% are either working children with few family ties who view the streets as their homes or abandoned and neglected children with no family ties. The National Policy for Children established in 1974 emphasizes the provision of equal opportunities for the development to all children during their growing years. Policy stresses programs to maintain, educate, and train destitute children and orphans. Policy is also to protect children against neglect, cruelty, and exploitation, but this is only on paper. An UNICEF study found that almost 40,000 children die every day in developing countries, 25% of whom are in India. Studies in some major cities indicate that the street children in India are of moderate health status, suffering from various chronic diseases and undernourishment. They are deprived of all health programs, but seem to prefer government hospitals in case of dire need. Street children often have to pay for water. Almost 97% in Calcutta, 99% in Bangalore, and 90% in Madras reported having no access to toilet and bathing facilities; 83% in Kanpur, however, had access to such facilities. Nothing has been heard in recent years of the National Children's Board established in 1975. Apparently the board has gradually waned. Various schemes were planned in 1992 by the Union Welfare Ministry in association with UNICEF. Extending extra health facilities, establishing nutrition programs, providing vocational training, protecting children from abuse, distributing dry-food polypacks, providing night shelters, providing ration cards, and creating bathing and toilet facilities would go far in improving the quality of life and the future of street children in India.

  8. Terrestrial Sediments of the Earth: Development of a Global Unconsolidated Sediments Map Database (GUM)

    Science.gov (United States)

    Börker, J.; Hartmann, J.; Amann, T.; Romero-Mujalli, G.

    2018-04-01

    Mapped unconsolidated sediments cover half of the global land surface. They are of considerable importance for many Earth surface processes like weathering, hydrological fluxes or biogeochemical cycles. Ignoring their characteristics or spatial extent may lead to misinterpretations in Earth System studies. Therefore, a new Global Unconsolidated Sediments Map database (GUM) was compiled, using regional maps specifically representing unconsolidated and quaternary sediments. The new GUM database provides insights into the regional distribution of unconsolidated sediments and their properties. The GUM comprises 911,551 polygons and describes not only sediment types and subtypes, but also parameters like grain size, mineralogy, age and thickness where available. Previous global lithological maps or databases lacked detail for reported unconsolidated sediment areas or missed large areas, and reported a global coverage of 25 to 30%, considering the ice-free land area. Here, alluvial sediments cover about 23% of the mapped total ice-free area, followed by aeolian sediments (˜21%), glacial sediments (˜20%), and colluvial sediments (˜16%). A specific focus during the creation of the database was on the distribution of loess deposits, since loess is highly reactive and relevant to understand geochemical cycles related to dust deposition and weathering processes. An additional layer compiling pyroclastic sediment is added, which merges consolidated and unconsolidated pyroclastic sediments. The compilation shows latitudinal abundances of sediment types related to climate of the past. The GUM database is available at the PANGAEA database (https://doi.org/10.1594/PANGAEA.884822).

  9. Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads

    Science.gov (United States)

    Dean, David; Topping, David; Schmidt, John C.; Griffiths, Ronald; Sabol, Thomas

    2016-01-01

    The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphic data to determine the cumulative influence of different flood types on changing channel form. In this study, physically based analyses suggest that channel change in the Rio Grande is controlled by both changes in flow strength and sediment supply over different spatial and temporal scales. Channel narrowing is primarily caused by substantial deposition of sediment supplied to the Rio Grande during tributary-sourced flash floods. Tributary floods have large suspended-sediment concentrations, occur for short durations, and attenuate rapidly downstream in the Rio Grande, depositing much of their sediment in downstream reaches. Long-duration floods on the mainstem have the capacity to enlarge the Rio Grande, and these floods, released from upstream dams, can either erode or deposit sediment in the Rio Grande depending upon the antecedent in-channel sediment supply and the magnitude and duration of the flood. Geomorphic and sediment transport analyses show that the locations and rates of sand erosion and deposition during long-duration floods are most strongly controlled by spatial changes in flow strength, largely through changes in channel slope. However, spatial differences in the in-channel sediment supply regulate sediment evacuation or accumulation over time in long reaches (greater than a kilometer).

  10. Street Cries and the urban refrain

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2012-01-01

    Rasmussen have investigated Danish street cries as respectably a musical and a spatial phenomenon. Such studies – from each their perspectives – can be said to explore the aesthetics of urban environments, since street calls are specifically developed and heard in the context of the city. Investigating...... the different methods employed in the two studies and presenting Deleuze and Guattaris theory about the refrain as a framework for further studies in the field, this article seeks to outline a fertile area of study for sound studies: the investigation of everyday refrains and the environmental relations...

  11. Citygml and the Streets of New York - a Proposal for Detailed Street Space Modelling

    Science.gov (United States)

    Beil, C.; Kolbe, T. H.

    2017-10-01

    Three-dimensional semantic city models are increasingly used for the analysis of large urban areas. Until now the focus has mostly been on buildings. Nonetheless many applications could also benefit from detailed models of public street space for further analysis. However, there are only few guidelines for representing roads within city models. Therefore, related standards dealing with street modelling are examined and discussed. Nearly all street representations are based on linear abstractions. However, there are many use cases that require or would benefit from the detailed geometrical and semantic representation of street space. A variety of potential applications for detailed street space models are presented. Subsequently, based on related standards as well as on user requirements, a concept for a CityGML-compliant representation of street space in multiple levels of detail is developed. In the course of this process, the CityGML Transportation model of the currently valid OGC standard CityGML2.0 is examined to discover possibilities for further developments. Moreover, a number of improvements are presented. Finally, based on open data sources, the proposed concept is implemented within a semantic 3D city model of New York City generating a detailed 3D street space model for the entire city. As a result, 11 thematic classes, such as roadbeds, sidewalks or traffic islands are generated and enriched with a large number of thematic attributes.

  12. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2......, 4 and 5, respectively. It is not the intention of the book to give a broad review of the literature on this very wide topic. The book tries to pick up information which is of engineering importance. An obstacle to the study of sedimentation is the scale effect in model tests. Whenever small...

  13. Fine sediment erodibility in Lake Okeechobee, Florida

    OpenAIRE

    Mehta, Ashish J.; Hwang, Kyu-Nam

    1989-01-01

    The critical need to predict the turbidity in water due to fine-grained sediment suspension under wave action over mud deposits for sedimentation and erosion studies, as well as sorbed contaminant transport, is well known. Since fall velocities of fine sediment particles are very small, they can be easily transported by hydrodynamic flows such as waves and currents. The presence of these particles in the water column affects accoustic transmission, heat absorption and depth of ...

  14. Relationships between the Brook Street Terrane and Median Tectonic Zone (Median Batholith) : evidence from Jurassic conglomerates

    International Nuclear Information System (INIS)

    Tulloch, A.J.; Kimbrough, D.L.; Landis, C.A.; Mortimer, N.; Johnston, M.R.

    1999-01-01

    U-Pb zircon ages of 237-180 Ma and c. 280 Ma of seven granitoid clasts from the Rainy River Conglomerate which lies within the eastern Median Tectonic Zone (Median Batholith) in Nelson, and the Barretts Formation of the Brook Street Terrane in Southland, constrain the depositional ages of both units to be no older than c. 180-200 Ma (Early Jurassic). The minimum age of the Rainy River Conglomerate is constrained by the 147 +2 -1 Ma (Latest Jurassic) emplacement age of the One Mile Gabbronorite (new name: previously western Buller Diorite). The ages and chemistry of five of the granitoid clasts are broadly compatible with derivation from rocks that are now represented by Triassic plutons of the Median Tectonic Zone (Median Batholith), although ages as young as 180 Ma are slightly outside the range of the latter as currently exposed in New Zealand. The age (273-290 Ma, 237 +/- 3 Ma) and chemistry of the other two clasts (one each from Rainy River Conglomerate and Barretts Formation) suggest derivation from the Brook Street Terrane. Similarity in stratigraphic age, depositional characteristics, granitoid clast ages and composition between Rainy River Conglomerate and Barretts Formation suggests that they are broadly correlative and collectively overlapped a combined Brook Street Terrane - Median Batholith (MTZ) before the Late Jurassic (147 +2 -1 Ma). Sedimentary overlap may also have continued across to Middle Jurassic conglomeratic strata in the Murihiku Terrane to the east of the Brook Street Terrane. A U-Pb zircon age of 261 +/- 2 Ma is reported for Pourakino Trondhjemite of the Brook Street Terrane. (author). 56 refs., 10 figs., 4 tabs

  15. PATTERNS OF SUBSTANCE ABUSE AMONG KENYAN STREET ...

    African Journals Online (AJOL)

    A sample of 50 (36 male and 14 female) street children currently in a remand home at Kabete in Nairobi, Kenya, were interviewed using a predesigned questionnaire in order to estimate prevalence rates for use of selected substances. The lifetime prevalence rates of the drugs most commonly used were volatile ...

  16. Wall Street sours on nuke plants

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    Wall Street has been threatening to join the antinuclear campaign for years as construction lead times and costs grew and the financial condition of utilities building reactors deteriorated. With nuclear plant cancellations, licensing problems, quality-assurance breakdowns, and elevated costs, stock prices have dropped causing unrest among utility investors

  17. Smart street lights using power line communication

    CSIR Research Space (South Africa)

    Du Toit, P

    2017-09-01

    Full Text Available The increasing popularity of automation has resulted in the development of “smart” systems for a variety of different applications. One such application is street lighting which still mostly uses very primitive methods of maintenance. The use...

  18. [Agnosia for streets and defective root finding].

    Science.gov (United States)

    Takahashi, Nobuyoshi

    2011-08-01

    Topographical disorientation is identified as a condition in which patients are unable to find their way in familiar surroundings, such as their home neighborhood or the admitting hospital after the onset of illness. I proposed to classify topographical disorientation into two categories: agnosia for streets (landmark agnosia) and defective root finding (heading disorientation). Patients with agnosia for streets are unable to identify familiar buildings and landscapes. They can, however, morphologically perceive them and remember their way around familiar areas. The lesions are located in the right posterior part of the parahippocampus gyrus, anterior half of the lingual gyrus and adjacent fusiform gyrus. Clinical findings and functional imaging studies suggest that these regions play a crucial role in the interaction between the visual information of streets and memories of them, which are thought to be retained in the right anterior part of the temporal lobe. In particular, the posterior part of the parahippocampus gyrus is critical for the acquisition of novel information. On the other hand, patients with defective root finding can identify familiar streets, but cannot remember their own location or positional relation between two points within a comparatively wide range not surveyable at one time. The lesions are located in the right retrosplenial cortex (Areas 29, 30), posterior cingulate cortex (Areas 23, 31) and precuneus. Clinical findings and functional imaging studies suggest that these regions are involved in the orientation function for navigating in wide spaces. In particular, the retrosplenial cortex is critical for encoding novel information.

  19. Vortex Cloud Street during AMTEX 75

    DEFF Research Database (Denmark)

    Jensen, Niels Otto; Agee, E. M.

    1978-01-01

    Strong northerly flow across Cheju Island, Korea, during the 1975 Air Mass Transformation Experiment (AMTEX 75) resulted in a pronounced vortex cloud street to the lee of the island on February 17 1975. This pattern has been studied and explained in terms of classical von Karman eddies shed...

  20. CONSUMPTION PATTERNS OF STREET FOOD CONSUMERS IN ...

    African Journals Online (AJOL)

    user

    diet of people living in low- and middle-income countries ... market for SF consumers in Cape Town. However, most ... beverages prepared and/or sold by vendors and hawkers ... many street-food items sold are unhealthy ...... going children in lower-income groups, who may ... The dangers of regular consumption of sugar-.

  1. Opportunities and constraints facing informal street traders ...

    African Journals Online (AJOL)

    A small income and the limited ability of the government and the formal business sector to provide sufficient employment opportunities to people in the economically active age categories are two of the main reasons for informal trading in South African cities. As a result, the informal street trading sector plays an important ...

  2. The Earl Lee Street Art Campaign

    Science.gov (United States)

    Bubba

    2013-01-01

    This article describes a catchy phrase with more to its meaning than first view. A slogan "All the girls love Earl Lee," appears in street art around the world. Earl Lee is a lovable, handsome man who owns the fictitious Earl Lube industries. Originally intended to bring a smile to people's faces at a time when there wasn't much to smile…

  3. Social Sustainability of Shopping Streets in Ankara

    Directory of Open Access Journals (Sweden)

    Özge YALÇINER ERCOŞKUN

    2013-02-01

    Full Text Available Shopping streets are integral parts of public spaces in traditional shopping areas of Central Business Districts (CBD. Furthermore, as modern shopping venues, shopping centers offer advantages for modern lifestyles with spacious shopping areas, variety of commercial and social activities, and economic value of their investments. These advantages act in favor of shopping centers and improve the level of shopping street social sustainability and its relevant concepts. The aim of this study is to analyze the main shopping streets of Ankara, using the concepts of social sustainability. In this study, these concepts, such as locality, identity, vitality, viability, sense of place, conviviality, meaning and local characteristics of the shopping streets are investigated. For the first time, the retail unit locations in Ankara, their brands and their business types, are illustrated on thematic land use maps using Geographical Information Systems (GIS software. Next, population activities and consumer spatial behavior are observed and marked on maps that are also referred to as social sustainability maps. The results of the study can be useful in formulating strategies within the framework of social sustainability, which is a relatively new concept.

  4. Agnosia for streets and defective root finding

    International Nuclear Information System (INIS)

    Takahashi, Nobuyoshi

    2011-01-01

    Topographical disorientation is identified as a condition in which patients are unable to find their way in familiar surroundings, such as their home neighborhood or the admitting hospital after the onset of illness. I proposed to classify topographical disorientation into two categories: agnosia for streets (landmark agnosia) and defective root finding (heading disorientation). Patients with agnosia for streets are unable to identify familiar buildings and landscapes. They can, however, morphologically perceive them and remember their way around familiar areas. The lesions are located in the right posterior part of the parahippocampus gyrus, anterior half of the lingual gyrus and adjacent fusiform gyrus. Clinical findings and functional imaging studies suggest that these regions play a crucial role in the interaction between the visual information of streets and memories of them, which are thought to be retained in the right anterior part of the temporal lobe. In particular, the posterior part of the parahippocampus gyrus is critical for the acquisition of novel information. On the other hand, patients with defective root finding can identify familiar streets, but cannot remember their own location or positional relation between two points within a comparatively wide range not surveyable at one time. The lesions are located in the right retrosplenial cortex (Areas 29, 30), posterior cingulate cortex (Areas 23, 31) and precuneus. Clinical findings and functional imaging studies suggest that these regions are involved in the orientation function for navigating in wide spaces. In particular, the retrosplenial cortex is critical for encoding novel information. (author)

  5. Turbulent ventilation of a street canyon

    DEFF Research Database (Denmark)

    Nielsen, Morten

    2000-01-01

    A selection of turbulence data corresponding to 185 days of field measurements has een analysed. The non-ideal building geometry influenced the circulation patterns in the street canyon and the largest average vertical velocities were observed in the wake of an unbroken line of buildings. The sta...

  6. Travel Time Estimation on Urban Street Segment

    Directory of Open Access Journals (Sweden)

    Jelena Kajalić

    2018-02-01

    Full Text Available Level of service (LOS is used as the main indicator of transport quality on urban roads and it is estimated based on the travel speed. The main objective of this study is to determine which of the existing models for travel speed calculation is most suitable for local conditions. The study uses actual data gathered in travel time survey on urban streets, recorded by applying second by second GPS data. The survey is limited to traffic flow in saturated conditions. The RMSE method (Root Mean Square Error is used for research results comparison with relevant models: Akcelik, HCM (Highway Capacity Manual, Singapore model and modified BPR (the Bureau of Public Roads function (Dowling - Skabardonis. The lowest deviation in local conditions for urban streets with standardized intersection distance (400-500 m is demonstrated by Akcelik model. However, for streets with lower signal density (<1 signal/km the correlation between speed and degree of saturation is best presented by HCM and Singapore model. According to test results, Akcelik model was adopted for travel speed estimation which can be the basis for determining the level of service in urban streets with standardized intersection distance and coordinated signal timing under local conditions.

  7. Politicians, Managers, and Street-Level Bureaucrats

    DEFF Research Database (Denmark)

    J. May, Peter; Winter, Søren

    This article addresses the influence of politicians, managers, and the dispositions of street-level bureaucrats in shaping actions at the frontlines of policy implementation. We investigate these for the implementation of employment policy reforms in Denmark. Our findings show a large percentage ...

  8. A remote coal deposit revisited

    DEFF Research Database (Denmark)

    Bojesen-Kofoed, Jørgen A.; Kalkreuth, Wolfgang; Petersen, Henrik I.

    2012-01-01

    discovery. The outcrops found in 2009 amount to approximately 8 m of sediment including a coal seam of 2 m thickness. More outcrops and additional coal deposits most certainly are to be found, pending further fieldwork. The deposits are Middle Jurassic, Callovian, in age and were deposited in a floodplain...... environment related to meandering river channels. Spores and pollen in the lower fluvial deposits reflect abundant vegetation of ferns along the river banks. In contrast, a sparse spore and pollen flora in the coals show a mixed vegetation of ferns and gymnosperms. Based on proximate and petrographic analyses...

  9. Flocculation Dynamics of cohesive sediment

    NARCIS (Netherlands)

    Maggi, F.

    2005-01-01

    Cohesive sediment suspended in natural waters is subject not only to transport and deposition processes but also to reactions of flocculation, \\textit{i.e.} aggregation of fine particles, and breakup of aggregates. Although aggregation and breakup occur at small and very small length scales compared

  10. Streets? Where We're Going, We Don't Need Streets

    Science.gov (United States)

    Bailey, J.

    2017-12-01

    In 2007 Google Street View started as a project to provide 360-degree imagery along streets, but in the decade since has evolved into a platform through which to explore everywhere from the slope of everest, to the middle of the Amazon rainforest to under the ocean. As camera technology has evolved it has also become a tool for ground truthing maps, and provided scientific observations, storytelling and education. The Google Street View "special collects" team has undertaken increasingly more challenging projects across 80+ countries and every continent. All of which culminated in possibly the most ambitious collection yet, the capture of Street View on board the International Space Station. Learn about the preparation and obstacles behind this and other special collects. Explore these datasets through both Google Earth and Google Expeditions VR, an educational tool to take students on virtual field trips using 360 degree imagery.

  11. Tobacco Taxation, Smuggling, and Street Tobacco Vendors in Eritrea

    International Development Research Centre (IDRC) Digital Library (Canada)

    The bulk of the smuggled cigarettes are sold by street vendors, many of them women and children, ... and its implications for government revenue;; identify the reasons why people sell on the streets; and, ... Agent(e) responsable du CRDI.

  12. Reproductive health behaviour of street youth and associated ...

    African Journals Online (AJOL)

    McRoy

    2014-03-30

    Mar 30, 2014 ... street, alcohol drinking, cigarette smoking and khat chewing. Among the .... Street youth: In this study, youth is defined as the people ... factors that influence sexual behaviours of ... means of preventing pregnancy. Condom ...

  13. Soft-sediment mullions

    Science.gov (United States)

    Ortner, Hugo

    2015-04-01

    In this contribution I describe the appearance, formation and significance of soft-sediment mullions. I use several examples from synorogenic turbidites of the Alps and the Pyrenees to show their appearance in the field. Soft-sediment mullions are elongate, slightly irregular bulges at the base of coarse-grained clastic beds (sand to conglomerate), separated by narrow, elongate flames of fine-grained material (mud) protruding into the coarse-grained bed. Various processes may lead to the formation of such structures: (1) longitudinal furrows parallel to the sediment transport direction may form by spiral motion in flow rolls during sediment transport (Dzulinski, 1966; Dzulinski & Simpson, 1966). (2) Loading combined with downslope movement can produce elongate structures parallelling the dowslope direction (Anketell et al., 1970). (3) Soft-sediment mullions are oriented perpendicular or oblique to the downslope direction, and show evidence of bedding-parallel shortening. Thus, they resemble cuspate-lobate folds or mullions, which are well-known in ductile structural geology (e.g. Urai et al., 2001). Soft-sediment mullions have been observed in two cases: Either bedding-parallel shortening can be achieved by slump processes, or by active tectonic shortening. Slumping is characterized by an alternation of stretching and shortening (e.g. Ortner, 2007; Alsop & Marco 2014), and therefore mullions do overprint or are overprinted by normal faults. In active depositional systems that are subject to tectonic shortening growth strata will form, but sediments already deposited will be shortened during lithification. In some cases, the formation of soft-sediment mullions predates folding, but the most widespread expression of syn-lithification shortening seems to be soft-sediment mullions, that form in the inner arcs of fold hinges. In the examples documented so far, the size of soft-sediment mullions is dependent on the grain-size of the coarse-grained layer, in which the

  14. POLICY EVALUATION OF RESTRUCTURING STREET VENDORS IN SURAKARTA CITY (Study of Street Vendors in Monument Park Banjarsari and Street Vendors in Manahan Stadium

    Directory of Open Access Journals (Sweden)

    Frahlevi Prajasari

    2015-08-01

    Full Text Available This study examined the policy evaluation of restructuring street vendors in Surakarta city. Street vendors represent the economic actors in the informal sector of urban economic activity. The government of City/District usually removes these street vendors by disguising this activity behind the reason of structuring, . The study used descriptive research with a qualitative approach. The relocation of street vendors in Surakarta City is orderly and smooth without violence which may impact badly on physic and material because the government of Surakarta City, especially Surakarta Mayor, uses persuasive approach. Notoharjo Market is a relocation place for street vendors at Banjarsari Monument Park. In the beginning, Notoharjo Market is crowded with buyers but current days, street vendors who occupy Notoharjo Market complain about lack of buyers. The lack of buyers at Notoharjo Market is because the facilities previously provided by the government of Surakarta City are not well maintained. The government of Surakarta City must listening all complains of street vendors for the smoothness and orderliness of trading activity of street vendors. Not only listening, but the government of Surakarta City also gives appropriate and best solution to street vendors such that street vendors feel comfort in selling and their income is better than before.

  15. Socio - demographic characteristics of child street vendors in Nnewi ...

    African Journals Online (AJOL)

    Background: Involvement of children in street trading is inimical, contrary to the Rights of the Child, and threatens holistic child development. Objective: To describe the sociodemographic characteristics of child street vendors in Nnewi. Method: A cross-sectional questionnaire survey of children selling wares on the streets of ...

  16. Street Food Consumption and its associated socio-demographic ...

    African Journals Online (AJOL)

    Street Food Consumption and its associated socio-demographic factors in Oyo town, Nigeria. ... Abstract. Background: Contemporary life-styles have made street foods to be an important meal option in Nigeria. They contribute ... Nutrition education is suggested for people to make a better choice of nourishing street foods.

  17. Psychosocial profile of institutionalised street children in Alexandria ...

    African Journals Online (AJOL)

    Objective: The phenomenon of street children in Egypt constitutes a public health concern. This study aimed to investigate the characteristics of institutionalised street children in Alexandria, to compare the prevalence of substance abuse and conduct disorder between street children and school children, and to identify ...

  18. An Art of Resistance: From the Street to the Classroom

    Science.gov (United States)

    Chung, Sheng Kuan

    2009-01-01

    Rooted in graffiti culture and its attitude toward the world, street art is regarded as a postgraffiti movement. Street art encompasses a wide array of media and techniques, such as traditional spray-painted tags, stickers, stencils, posters, photocopies, murals, paper cutouts, mosaics, street installations, performances, and video projections…

  19. Socio-demographic characteristics of street children in rural ... - Ibadan

    African Journals Online (AJOL)

    15.0%), part-time driving (9.5%) and car washing (5.0%) were the commonest types of work. Of those still schooling, 41.6% had no form of part-time work on the streets. None of the street children lived on the street with 65% still living with parents.

  20. Sediment traps with guiding channel and hybrid check dams improve controlled sediment retention

    Science.gov (United States)

    Schwindt, Sebastian; Franca, Mário J.; Reffo, Alessandro; Schleiss, Anton J.

    2018-03-01

    Sediment traps with partially open check dams are crucial elements for flood protection in alpine regions. The trapping of sediment is necessary when intense sediment transport occurs during floods that may endanger urban areas at downstream river reaches. In turn, the unwanted permanent trapping of sediment during small, non-hazardous floods can result in the ecological and morphological degradation of downstream reaches. This study experimentally analyses a novel concept for permeable sediment traps. For ensuring the sediment transfer up to small floods, a guiding channel implemented in the deposition area of a sediment trap was systematically studied. The bankfull discharge of the guiding channel corresponds to a dominant morphological discharge. At the downstream end of the guiding channel, a permeable barrier (check dam) triggers sediment retention and deposition. The permeable barrier consists of a bar screen for mechanical deposition control, superposed to a flow constriction for the hydraulic control. The barrier obstructs hazardous sediment transport for discharges that are higher than the bankfull discharge of the guiding channel without the risk of unwanted sediment flushing (massive self-cleaning).

  1. Radiocarbon dating of sediment cores from Hachinohe, the Kamikita Plain

    International Nuclear Information System (INIS)

    Hitoki, Eri; Nakamura, Toshio; Matsumoto, Yui; Tsuji, Sei-ichiro; Fujine, Hisashi

    2013-01-01

    We investigated stratigraphy and chronology by analyses of Holocene sediments and radiocarbon dating of sediment cores from the Kamikita Plain. On the Kamikita Plain, which faces the Pacific coast of Northeast Japan, marine and fluvial terraces covered with tephras derived from Towada and Hakkoda volcanoes are well developed. We clarified that Towada Chuseri tephra and fluvial deposits consisted of volcanic sediments influenced an alluvial depositional system in the Kamikita Plain after a maximum of the Jomon Transgression. (author)

  2. Coastal sediment dynamics in Spitsbergen

    Science.gov (United States)

    Deloffre, J.; Lafite, R.; Baltzer, A.; Marlin, C.; Delangle, E.; Dethleff, D.; Petit, F.

    2010-12-01

    In arctic knowledge on coastal sediment dynamics and sedimentary processes is limited. The studied area is located in the microtidal Kongsfjorden glacial fjord on the North-western coast of Spitsbergen in the Artic Ocean (79°N). In this area sediment contributions to the coastal zone is provided by small temporary rivers that flows into the fjord. The objectives of this study are to (i) assess the origin and fate of fine-grained particles (sea ice cover on sediment dynamics. The sampling strategy is based on characterization of sediment and SPM (grain-size, X-rays diffraction, SEM images, carbonates and organic matter contents) from the glacier to the coastal zone completed by a bottom-sediment map on the nearshore using side-scan sonar validated with Ekman binge sampling. River inputs (i.e. river plumes) to the coastal zone were punctually followed using CTD (conductivity, temperature, depth and turbidity) profiles. OBS (water level, temperature and turbidity) operating at high-frequency and during at least 1 years (including under sea ice cover) was settled at the mouth of rivers at 10m depth. In the coastal zone the fine-grained sediment deposit is limited to mud patches located at river mouths that originate the piedmont glacier. However a significant amount of sediment originates the coastal glacier located in the eastern part of the fjord via two processes: direct transfer and ice-drop. Results from turbidity measurements show that the sediment dynamics is controlled by river inputs in particular during melting period. During winter sediment resuspension can occurs directly linked to significant wind-events. When the sea ice cover is present (January to April) no sediment dynamics is observed. Sediment processes in the coastal zone of arctic fjords is significant however only a small amount of SPM that originates the river plume settles in the coastal zone; only the coarser material settles at the mouth of the river while the finer one is deposited further

  3. Sedimentation rates in Lake Pukaki, New Zealand

    International Nuclear Information System (INIS)

    Ditchburn, R.G.; McCabe, W.J.

    1977-10-01

    The layers of Lake Pukaki sediments and their possible relationship to other cyclic events have been considered with a view to determining the rate of sediment deposition. There was no evidence to determine whether the rhytmic layers in the sediments are annual deposits or controlled by flood conditions. In the hope of resolving the question, radiometric dating techniques were applied to sediment cores in which the concentrations of radionuclides such as lead 210 and caesium 137 were measured with respect to depth and then related to some known input pattern. 210 Pb and 137 Cs were determined in all three cores investigated. 147 Pr and 144 Ce were also determined in one of the cores. The 137 Cs measurements indicated sedimentation rates of 14 kg/y/m 2 for one core and 17 kg/y/m 2 for the other two

  4. LES of flow in the street canyon

    Science.gov (United States)

    Fuka, Vladimír; Brechler, Josef

    2012-04-01

    Results of computer simulation of flow over a series of street canyons are presented in this paper. The setup is adapted from an experimental study by [4] with two different shapes of buildings. The problem is simulated by an LES model CLMM (Charles University Large Eddy Microscale Model) and results are analysed using proper orthogonal decomposition and spectral analysis. The results in the channel (layout from the experiment) are compared with results with a free top boundary.

  5. Finding Street Gang Members on Twitter

    OpenAIRE

    Balasuriya, Lakshika; Wijeratne, Sanjaya; Doran, Derek; Sheth, Amit

    2016-01-01

    Most street gang members use Twitter to intimidate others, to present outrageous images and statements to the world, and to share recent illegal activities. Their tweets may thus be useful to law enforcement agencies to discover clues about recent crimes or to anticipate ones that may occur. Finding these posts, however, requires a method to discover gang member Twitter profiles. This is a challenging task since gang members represent a very small population of the 320 million Twitter users. ...

  6. Optically stimulated luminescence dating of young sediments

    DEFF Research Database (Denmark)

    Madsen, Anni Tindahl; Murray, Andrew S.

    2009-01-01

    of OSL dating, outlines the problems specific to the dating of young material, and then uses recent applications to young sediments to illustrate the greatly increased scope and potential of the method in geomorphology and the geology of recent deposits. The overall reliability of this new generation...... for determining the time of deposition of water-lain sediments from the coastal zone, and aeolian deposits from both coastal and inland environments. Our conclusion is supported by the growing popularity of OSL dating in geomorphology and geology...

  7. 75 FR 71744 - Fifth Street Finance Corp., et al.; Notice of Application

    Science.gov (United States)

    2010-11-24

    ... Street Finance Corp., et al.; Notice of Application November 18, 2010. AGENCY: Securities and Exchange... Street Finance Corp. (``Fifth Street''), Fifth Street Management LLC, Fifth Street Mezzanine Partners IV... regulated as a business development company (``BDC'') under the Act. Fifth Street is a specialty finance...

  8. Self-Localization at Street Intersections.

    Science.gov (United States)

    Fusco, Giovanni; Shen, Huiying; Coughlan, James M

    2014-05-01

    There is growing interest among smartphone users in the ability to determine their precise location in their environment for a variety of applications related to wayfinding, travel and shopping. While GPS provides valuable self-localization estimates, its accuracy is limited to approximately 10 meters in most urban locations. This paper focuses on the self-localization needs of blind or visually impaired travelers, who are faced with the challenge of negotiating street intersections. These travelers need more precise self-localization to help them align themselves properly to crosswalks, signal lights and other features such as walk light pushbuttons. We demonstrate a novel computer vision-based localization approach that is tailored to the street intersection domain. Unlike most work on computer vision-based localization techniques, which typically assume the presence of detailed, high-quality 3D models of urban environments, our technique harnesses the availability of simple, ubiquitous satellite imagery (e.g., Google Maps) to create simple maps of each intersection. Not only does this technique scale naturally to the great majority of street intersections in urban areas, but it has the added advantage of incorporating the specific metric information that blind or visually impaired travelers need, namely, the locations of intersection features such as crosswalks. Key to our approach is the integration of IMU (inertial measurement unit) information with geometric information obtained from image panorama stitchings. Finally, we evaluate the localization performance of our algorithm on a dataset of intersection panoramas, demonstrating the feasibility of our approach.

  9. Three Years Measuring Sediment Erosion and Deposition from the Largest Dam Removal Ever at Weekly-­to-­Monthly Scales Using SfM: Elwha River, Washington, USA.

    Science.gov (United States)

    Ritchie, A.; Randle, T. J.; Bountry, J.; Warrick, J. A.

    2015-12-01

    The stepwise removal of two dams on the Elwha River beginning in September 2011 exposed ~21 million cubic meters of sediment to fluvial erosion and created an unprecedented opportunity to monitor reservoir sediment erosion and river evolution during base level adjustment and a pulsed sediment release. We have conducted more than 60 aerial surveys with a Cessna 172 using a simple custom wing-mount for consumer grade cameras and SfM photogrammetry to produce orthoimagery and digital elevation models in near-real-time at weekly to monthly time intervals. Multiple lidar flights and ground survey campaigns have provided estimates of both systematic and random error for this uniquely dense dataset. Co-registration of multiple surveys during processing reduces systematic error and allows boot-strapping of subsequently established ground control to earlier flights. Measurements chronicle the erosion of 12 million cubic meters of reservoir sediment and record corresponding changes in channel braiding, wood loading and bank erosion. These data capture reservoir and river channel responses to dam removal at resolutions comparable to hydrologic forcing events, allowing us to quantify reservoir sediment budgets on a per-storm basis. This allows for the analysis of sediment transported relative to rates of reservoir drawdown and river stream power for dozens of intervals of time. Temporal decoupling of peak sediment flux and bank erosion rates is noted from these analyses. This dataset illustrates some of the challenges and opportunities emerging with the advent of big data in remote sensing of earth surface processes.

  10. Nearshore sediment thickness, Fire Island, New York

    Science.gov (United States)

    Locker, Stanley D.; Miselis, Jennifer L.; Buster, Noreen A.; Hapke, Cheryl J.; Wadman, Heidi M.; McNinch, Jesse E.; Forde, Arnell S.; Stalk, Chelsea A.

    2017-04-03

    Investigations of coastal change at Fire Island, New York (N.Y.), sought to characterize sediment budgets and determine geologic framework controls on coastal processes. Nearshore sediment thickness is critical for assessing coastal system sediment availability, but it is largely unquantified due to the difficulty of conducting geological or geophysical surveys across the nearshore. This study used an amphibious vessel to acquire chirp subbottom profiles. These profiles were used to characterize nearshore geology and provide an assessment of nearshore sediment volume. Two resulting sediment-thickness maps are provided: total Holocene sediment thickness and the thickness of the active shoreface. The Holocene sediment section represents deposition above the maximum flooding surface that is related to the most recent marine transgression. The active shoreface section is the uppermost Holocene sediment, which is interpreted to represent the portion of the shoreface thought to contribute to present and future coastal behavior. The sediment distribution patterns correspond to previously defined zones of erosion, accretion, and stability along the island, demonstrating the importance of sediment availability in the coastal response to storms and seasonal variability. The eastern zone has a thin nearshore sediment thickness, except for an ebb-tidal deposit at the wilderness breach caused by Hurricane Sandy. Thicker sediment is found along a central zone that includes shoreface-attached sand ridges, which is consistent with a stable or accretional coastline in this area. The thickest overall Holocene section is found in the western zone of the study, where a thicker lower section of Holocene sediment appears related to the westward migration of Fire Island Inlet over several hundred years.

  11. Sediment contributions from floodplains and legacy sediments to Piedmont streams of Baltimore County, Maryland

    Science.gov (United States)

    Donovan, Mitchell; Miller, Andrew; Baker, Matthew; Gellis, Allen

    2015-04-01

    Disparity between watershed erosion rates and downstream sediment delivery has remained an important theme in geomorphology for many decades, with the role of floodplains in sediment storage as a common focus. In the Piedmont Province of the eastern USA, upland deforestation and agricultural land use following European settlement led to accumulation of thick packages of overbank sediment in valley bottoms, commonly referred to as legacy deposits. Previous authors have argued that legacy deposits represent a potentially important source of modern sediment loads following remobilization by lateral migration and progressive channel widening. This paper seeks to quantify (1) rates of sediment remobilization from Baltimore County floodplains by channel migration and bank erosion, (2) proportions of streambank sediment derived from legacy deposits, and (3) potential contribution of net streambank erosion and legacy sediments to downstream sediment yield within the Mid-Atlantic Piedmont. We calculated measurable gross erosion and deposition rates within the fluvial corridor along 40 valley segments from 18 watersheds with drainage areas between 0.18 and 155 km2 in Baltimore County, Maryland. We compared stream channel and floodplain morphology from lidar-based digital elevation data collected in 2005 with channel positions recorded on 1:2400 scale topographic maps from 1959-1961 in order to quantify 44-46 years of channel change. Sediment bulk density and particle size distributions were characterized from streambank and channel deposit samples and used for volume to mass conversions and for comparison with other sediment sources. Average annual lateral migration rates ranged from 0.04 to 0.19 m/y, which represented an annual migration of 2.5% (0.9-4.4%) channel width across all study segments, suggesting that channel dimensions may be used as reasonable predictors of bank erosion rates. Gross bank erosion rates varied from 43 to 310 Mg/km/y (median = 114) and were

  12. Polymer platforms for selective detection of cocaine in street samples adulterated with levamisole.

    Science.gov (United States)

    Florea, Anca; Cowen, Todd; Piletsky, Sergey; De Wael, Karolien

    2018-08-15

    Accurate drug detection is of utmost importance for fighting against drug abuse. With a high number of cutting agents and adulterants being added to cut or mask drugs in street powders the number of false results is increasing. We demonstrate for the first time the usefulness of employing polymers readily synthesized by electrodeposition to selectively detect cocaine in the presence of the commonly used adulterant levamisole. The polymers were selected by computational modelling to exhibit high binding affinity towards cocaine and deposited directly on the surface of graphene-modified electrodes via electropolymerization. The resulting platforms allowed a distinct electrochemical signal for cocaine, which is otherwise suppressed by levamisole. Square wave voltammetry was used to quantify cocaine alone and in the presence of levamisole. The usefulness of the platforms was demonstrated in the screening of real street samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Austin, S.R.; D'Andrea, R.F. Jr.

    1978-01-01

    Three overall factors are necessary for formation of uranium deposits in sandstone: a source of uranium, host rocks capable of transmitting uranium-bearing solutions, and a precipitant. Possible sources of uranium in sandstone-type deposits include groundwaters emanating from granitic highlands, arkosic sediments, tuffaceous material within or overlying the host rocks, connate fluids, and overlying black shales. The first three sources are considered the most likely. Host rocks are generally immature sandstones deposited in alluvial-fan, intermontane-basin or marginal-marine environments, but uranium deposits do occur in well-winnowed barrier-bar or eolian sands. Host rocks for uranium deposits generally show coefficients of permeability on the order of 1 to 100 gal/day/ft 2 . Precipitants are normally agents capable of reducing uranium from the uranyl to the uranous state. The association of uranium with organic matter is unequivocal; H 2 S, a powerful reductant, may have been present at the time of formation of some deposits but may go unnoticed today. Vanadium can serve to preserve the tabular characteristics of some deposits in the near-surface environment, but is considered an unlikely primary precipitant for uranium. Uranium deposits in sandstone are divided into two overall types: peneconcordant deposits, which occur in locally reducing environments in otherwise oxidized sandstones; and roll-type deposits, which occur at the margin of an area where an oxidized groundwater has permeated an otherwise reduced sandstone. Uranium deposits are further broken down into four subclasses; these are described

  14. {sup 137}Cs in northern Adriatic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Barisic, D; Lulic, S; Vdovic, N; Vertacnik, A [Center for Marine Research - Department Zagreb, ' Ruder Boskovic' Institute, Zagreb (Croatia); Juracic, M [Department of Geology, Faculty of Natural Sciences, University of Zagreb, Zagreb (Croatia)

    1996-01-01

    The activity of {sup 137}Cs in shallow northern Adriatic sediments was obtained on the basis of measurement results from 25 sediment box cores, sampled during the Adriatic Scientific COoperation Program (ASCOP) 16 cruise in the summer 1990. {sup 137}Cs was determined in surface sediments (0-3 cm) and 12-15 cm-deep sediment. It was found that the lowest caesium concentrations correspond to sands, which are spread along the Croatian coast. Parallel to the Italian coast, {sup 137}Cs concentrations in pelites are the highest. It seems that the influence of Po River is significant for {sup 137}Cs activities in recent marine sediments along Italian coast south of Po River delta. Significantly higher {sup 137}Cs activities in 0-3 cm sediment layer can be attributed to the deposition caused by Chernobyl accident. (author)

  15. 137Cs in northern Adriatic sediments

    International Nuclear Information System (INIS)

    Barisic, D.; Lulic, S.; Vdovic, N.; Vertacnik, A.; Juracic, M.

    1996-01-01

    The activity of 137 Cs in shallow northern Adriatic sediments was obtained on the basis of measurement results from 25 sediment box cores, sampled during the Adriatic Scientific COoperation Program (ASCOP) 16 cruise in the summer 1990. 137 Cs was determined in surface sediments (0-3 cm) and 12-15 cm-deep sediment. It was found that the lowest caesium concentrations correspond to sands, which are spread along the Croatian coast. Parallel to the Italian coast, 137 Cs concentrations in pelites are the highest. It seems that the influence of Po River is significant for 137 Cs activities in recent marine sediments along Italian coast south of Po River delta. Significantly higher 137 Cs activities in 0-3 cm sediment layer can be attributed to the deposition caused by Chernobyl accident. (author)

  16. On luminescence bleaching of tidal channel sediments

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Pejrup, Morten; Murray, Andrew S.

    2015-01-01

    We investigate the processes responsible for bleaching of the quartz OSL signal from tidal channel sediment. Tidal dynamics are expected to play an important role for complete bleaching of tidal sediments. However, no studies have examined the amount of reworking occurring in tidal channels...... and on tidal flats due to the mixing caused by currents and waves. We apply bed level data to evaluate the amount of vertical sediment reworking in modern tidal channels and at a tidal flat. Cycles of deposition and erosion are measured with a bed level sensor, and the results show that gross sedimentation...... was several times higher than net sedimentation. We propose that tidal channel sediment is bleached either on the tidal flat before it is transported to the tidal channels and incorporated in channel-fill successions or, alternatively, on the shallow intertidal part of the channel banks. Based...

  17. Air quality considerations for stormwater green street design.

    Science.gov (United States)

    Shaneyfelt, Kathryn M; Anderson, Andrew R; Kumar, Prashant; Hunt, William F

    2017-12-01

    Green streets are increasingly being used as a stormwater management strategy to mitigate stormwater runoff at its source while providing other environmental and societal benefits, including connecting pedestrians to the street. Simultaneously, human exposure to particulate matter from urban transportation is of major concern worldwide due to the proximity of pedestrians, drivers, and cyclists to the emission sources. Vegetation used for stormwater treatment can help designers limit the exposure of people to air pollutants. This goal can be achieved through the deliberate placement of green streets, along with strategic planting schemes that maximize pollutant dispersion. This communication presents general design considerations for green streets that combine stormwater management and air quality goals. There is currently limited guidance on designing green streets for air quality considerations; this is the first communication to offer suggestions and advice for the design of green stormwater streets in regards to their effects on air quality. Street characteristics including (1) the width to height ratio of the street to the buildings, (2) the type of trees and their location, and (3) any prevailing winds can have an impact on pollutant concentrations within the street and along sidewalks. Vegetation within stormwater control measures has the ability to reduce particulate matter concentrations; however, it must be carefully selected and placed within the green street to promote the dispersion of air flow. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Contemporary sediment-transport processes in submarine canyons.

    Science.gov (United States)

    Puig, Pere; Palanques, Albert; Martín, Jacobo

    2014-01-01

    Submarine canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through canyons. Additionally, internal waves periodically resuspend ephemeral deposits within canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches for decades or centuries before being completely or partially flushed farther down-canyon by large sediment failures.

  19. Re-entrained road dust PM10 emission from selected streets of Krakow and its impact on air quality

    Directory of Open Access Journals (Sweden)

    Bogacki Marek

    2018-01-01

    Full Text Available Scientific research studies conducted in various parts of the world confirm that PM10 concentrations in urban air depend to a great extent on the resuspension processes of the dust deposited on the road surface. The paper presents the results of the study related to the determination of the re-entrained PM10 emissions from four selected streets of Krakow (Southern Poland together with the assessment of its impact on air quality. Examined streets are characterised by different traffic intensity (from 500 to over 20 000 vehicles per day and individual vehicle structure. Dust material sampling and estimation of the PM10 emission were conducted according to the U.S. EPA methodology (AP 42 Fifth Edition. Two variants of sample collection were applied: from the road surface including the area at the curb (4 streets and from the road surface alone (1 street. The estimates of resuspended road dust emission as well as the reference values derived from the U.S. EPA guidelines were used to assess the impact of this emission on the PM10 levels in the air at the location of one of the analysed streets. This assessment was conducted using the CALINE4 mathematical model. The study showed that the PM10 emissions from the re-entrained road dust can be responsible for up to 25 % in the winter and 50 % in the summer of the total PM10 concentrations in the air near the roads.

  20. Re-entrained road dust PM10 emission from selected streets of Krakow and its impact on air quality

    Science.gov (United States)

    Bogacki, Marek; Mazur, Marian; Oleniacz, Robert; Rzeszutek, Mateusz; Szulecka, Adriana

    2018-01-01

    Scientific research studies conducted in various parts of the world confirm that PM10 concentrations in urban air depend to a great extent on the resuspension processes of the dust deposited on the road surface. The paper presents the results of the study related to the determination of the re-entrained PM10 emissions from four selected streets of Krakow (Southern Poland) together with the assessment of its impact on air quality. Examined streets are characterised by different traffic intensity (from 500 to over 20 000 vehicles per day) and individual vehicle structure. Dust material sampling and estimation of the PM10 emission were conducted according to the U.S. EPA methodology (AP 42 Fifth Edition). Two variants of sample collection were applied: from the road surface including the area at the curb (4 streets) and from the road surface alone (1 street). The estimates of resuspended road dust emission as well as the reference values derived from the U.S. EPA guidelines were used to assess the impact of this emission on the PM10 levels in the air at the location of one of the analysed streets. This assessment was conducted using the CALINE4 mathematical model. The study showed that the PM10 emissions from the re-entrained road dust can be responsible for up to 25 % in the winter and 50 % in the summer of the total PM10 concentrations in the air near the roads.

  1. Vermeer's The Little Street: a precise location

    Directory of Open Access Journals (Sweden)

    Frans Grijzenhout

    2018-03-01

    Full Text Available In the autumn of 2015, Frans Grijzenhout published his sensational findings regarding the likely location of Johannes Vermeer’s ‘little street’ (The Little Street. After consulting a variety of sources, including the ‘The Ledger of Dredging of the Canals in the Town of Delft’ from 1666–1667, he had reached the conclusion that the famous painting by Vermeer must have been based on the houses and two intervening passageways that in Vermeer’s day stood on Vlamingstraat, an unassuming canal in the eastern part of Delft, where numbers 40 and 42 stand today. He had also ascertained that one of Vermeer’s aunts, Ariaentgen Claes van der Minne, was the occupant of 42 Vlamingstraat at that time. Several authors have since produced material indicating that Vermeer painted the right-hand house in Little Street ‘from life’: the house was, it now appears, observed and reproduced in meticulous detail. The same can now be confirmed for other aspects, such as the colour used for the painted shutters and the recesses for wind hooks in the sill of the window of the righthand house. Philip Steadman has rightly pointed to an apparent discrepancy of four feet (c. 1.25 m. between the details in the aforementioned ‘Ledger of the Dredging of the Canals in the Town of Delft’ and the actual spatial situation at 40 Vlamingstraat. This difference can be traced back to the fact that the gateway provided access to both front and back houses. Accordingly, the owners of both front and back houses would have been taxed on the width (four feet of the passageway. Given what we know about the meticulous precision with which the Ledger was compiled in the case of 42 Vlamingstraat, it is inconceivable that the authors of the register for number 40 should have made a mistake. A spatial rendering based on an earlier perspective study of The Little Street, corresponds surprisingly well, and in some respects in detail, with the cadastral and other information we

  2. Sediment Equilibrium and Diffusive Fluxes in Relation to Phosphorus Dynamics in the Turbid Minnesota River

    National Research Council Canada - National Science Library

    James, William F

    2009-01-01

    ...) concentration in large river systems. However, in-stream processes such as equilibrium P flux from suspended sediment and diffusive P flux from deposited sediment stored in river channels may also play a role in soluble P control...

  3. Numerical Coupling of River Discharge to Shelf/Slope Sedimentation Models

    National Research Council Canada - National Science Library

    Syvitski, James

    1997-01-01

    Scientific objectives of this project are: (1) Develop a nested set of models to study the interactions of sedimentation processes on the shelf, including the effects of river supply, plume transport and initial deposition of sediments; (2...

  4. Tidal-scale flow routing and sedimentation in mangrove forests: combining field data and numerical modelling

    NARCIS (Netherlands)

    Horstman, Erik; Dohmen-Janssen, Catarine M.; Bouma, T.J.; Hulscher, Suzanne J.M.H.

    2015-01-01

    Tidal-scale biophysical interactions establish particular flow routing and sedimentation patterns in coastal mangroves. Sluggish water flows through the mangrove vegetation and enhanced sediment deposition are essential to maintain these valuable ecosystems, thereby enabling their contribution to

  5. SEDIMENTATION IN PACIFIC NORTHWEST COASTAL STREAMS -- EVIDENCE FROM REGIONAL SURVEY OF BED SUBSTRATE SIZE AND STABILITY

    Science.gov (United States)

    Excessive erosion, transport and deposition of sediment are major problems in streams and rivers throughout the United States. We examined evidence of anthropogenic sedimentation in Oregon and Washington coastal streams using relatively rapid measurements taken from surveys duri...

  6. Larval Fish Feeding Responses to Variable Suspended Sediment and Planktonic Prey Concentrations

    National Research Council Canada - National Science Library

    Colby, D

    2004-01-01

    ... impacts from dredging projects. For example, in the context of nearshore placement of mixed sediments, concerns have been raised that winnowing of fine sediments from deposited dredged material may elevate turbidity and have a...

  7. [Homeless on the streets of Copenhagen].

    Science.gov (United States)

    Nordentoft, M

    1994-05-16

    A group of homeless people living in the streets is described with the purpose of gaining the knowledge necessary to prevent development of homelessness and establishing programmes for the homeless. Out-reach work in the streets and cooperation with private and religious organisations was conducted during a two-year period and 59 homeless persons were interviewed. Fifteen were women and 44 were men. Upbringing, social conditions, daily living, physical and mental health and contact with health services, social security and private organisations were highlighted in a structured and semistructured interview. Compared with the background population the homeless had much more frequently childhood experience of parents' divorce or death of one of the parents. The women were significantly older than the men and the majority of the women were suffering from schizophrenia and had very little contact with network and public services. The majority of the men were abusing alcohol or drugs, many had had a troublesome childhood with stays in institutions. Many had had many contacts with different social institutions and a criminal record. Among the homeless in the streets of Copenhagen, the prevalence of mental illness, especially schizophrenia, is high. It is recommended that homelessness among the mentally ill is prevented by a special effort directed towards the patient group at risk of becoming homeless and through establishing different housing facilities with varying degrees of professional support. Out-reach work towards the homeless mentally ill should be carried out with the purpose of establishing contact with psychiatric services and securing the possibility of compulsory admission.

  8. Politicians, Managers, and Street-Level Bureaucrats

    DEFF Research Database (Denmark)

    May, Peter J.; Winter, Søren

    2010-01-01

    This article addresses the influence of politicians, managers, and the dispositions of street-level bureaucrats in shaping actions at the frontlines of policy implementation. We investigate these for the implementation of employment policy reforms in Denmark. Our findings show a large percentage...... of caseworkers emphasizing actions that are consistent with the national employment reform goal of getting clients into jobs quickly. The influence of politicians and managers in bringing this about is relatively limited in comparison to the influences of caseworkers’ understanding of policy goals...

  9. Politicians, Managers, and Street-Level Bureaucrats

    DEFF Research Database (Denmark)

    J. May, Peter; Winter, Søren

    2009-01-01

    This article addresses the influence of politicians, managers, and the dispositions of street-level bureaucrats in shaping actions at the frontlines of policy implementation. We investigate these for the implementation of employment policy reforms in Denmark. Our findings show a large percentage...... of caseworkers emphasizing actions that are consistent with the national employment reform goal of getting clients into jobs quickly. The influence of politicians and managers in bringing this about is relatively limited in comparison to the influences of caseworkers’ understanding of policy goals...

  10. Philippines: street children, children at risk.

    Science.gov (United States)

    Tantoco, F G

    1993-01-01

    Almost 2 million of Manila's 2.5 million children younger than 15 years old live on or below the poverty line. 75,000 of these children live on the streets after having run away from home or being abandoned. They beg, steal, scavenge for food, and sell newspapers, cigarettes, and leis. About 20,000 of the street children prostitute themselves. It is these latter children and adolescents who are at particular risk of HIV infection. Studies in the Philippines indicate that 91% of reported HIV infections are among individuals aged 15-44, the male/female infection ratio is one to one, the transmission rate is 45%, and the most common mode of transmission is through heterosexual intercourse. The high incidence of child sexual abuse and child prostitution in the Philippines would suggest that there are a significant number of children and adolescents under age 15 who are infected with HIV. Caritas Manila has developed an information, education, and communication program for HIV/AIDS prevention focusing upon individuals who have direct influence upon and are in direct contact with people: clergy, religious and civic associations, educators, and social and health workers. Caritas has also to a limited extent reached out directly to populations at risk, while collaborating with human rights advocacy groups and networking with other children-oriented agencies in the interest of providing resources to street children. Efforts must be made to protect the rights of children and provide them with an environment conducive to their growth and development. The author notes how off-duty policemen in Manila help real estate developers forcibly eject the poor from their shelters to clear the way for the construction of new infrastructure without concern for the legal processes and requirements in the humane and peaceful relocation of the homeless poor. Many women and children are hurt and killed in the process. It has also been reported that off-duty policemen in Rio de Janeiro

  11. CONTROLLING STREET DOG POPULATION IN MOSCOW

    OpenAIRE

    ZHULENKO A.S.; POLYNOVA G.V.

    2016-01-01

    The issue represents the analysis of the fundamentals and world-wide best practices of controlling street dog population in Moscow and other global cities. Actions proposed to improve the strategy of managing free-ranging dogs in Moscow.Some reasons of increase in number of stray dogs and “pet overpopulation” ware studied. There are ecological types of stray dogs characterized the types of running wild of dogs and foraging (food procurement) strategy of animals.The analysis of the basic princ...

  12. Potential reductions of street solids and phosphorus in urban watersheds from street cleaning, Cambridge, Massachusetts, 2009-11

    Science.gov (United States)

    Sorenson, Jason R.

    2013-01-01

    Material accumulating and washing off urban street surfaces and ultimately into stormwater drainage systems represents a substantial nonpoint source of solids, phosphorus, and other constituent loading to waterways in urban areas. Cost and lack of usable space limit the type and number of structural stormwater source controls available to municipalities and other public managers. Non-structural source controls such as street cleaning are commonly used by cities and towns for construction, maintenance and aesthetics, and may reduce contaminant loading to waterways. Effectiveness of street cleaning is highly variable and potential improvements to water quality are not fully understood. In 2009, the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, the U.S. Environmental Protection Agency, and the city of Cambridge, Massachusetts, and initiated a study to better understand the physical and chemical nature of the organic and inorganic solid material on street surfaces, evaluate the performance of a street cleaner at removing street solids, and make use of the Source Loading and Management Model (SLAMM) to estimate potential reductions in solid and phosphorus loading to the lower Charles River from various street-cleaning technologies and frequencies. Average yield of material on streets collected between May and December 2010, was determined to be about 740 pounds per curb-mile on streets in multifamily land use and about 522 pounds per curb-mile on commercial land-use streets. At the end-of-winter in March 2011, about 2,609 and 4,788 pounds per curb-mile on average were collected from streets in multifamily and commercial land-use types, respectively. About 86 percent of the total street-solid yield from multifamily and commercial land-use streets was greater than or equal to 0.125 millimeters in diameter (or very fine sand). Observations of street-solid distribution across the entire street width indicated that as

  13. Estuarine abandoned channel sedimentation rates record peak fluvial discharge magnitudes

    Science.gov (United States)

    Gray, A. B.; Pasternack, G. B.; Watson, E. B.

    2018-04-01

    Fluvial sediment deposits can provide useful records of integrated watershed expressions including flood event magnitudes. However, floodplain and estuarine sediment deposits evolve through the interaction of watershed/marine sediment supply and transport characteristics with the local depositional environment. Thus extraction of watershed scale signals depends upon accounting for local scale effects on sediment deposition rates and character. This study presents an examination of the balance of fluvial sediment dynamics and local scale hydro-geomorphic controls on alluviation of an abandoned channel in the Salinas River Lagoon, CA. A set of three sediment cores contained discrete flood deposits that corresponded to the largest flood events over the period of accretion from 1969 to 2007. Sedimentation rates scaled with peak flood discharge and event scale sediment flux, but were not influenced by longer scale hydro-meteorological activities such as annual precipitation and water yield. Furthermore, the particle size distributions of flood deposits showed no relationship to event magnitudes. Both the responsiveness of sedimentation and unresponsiveness of particle size distributions to hydro-sedimentological event magnitudes appear to be controlled by aspects of local geomorphology that influence the connectivity of the abandoned channel to the Salinas River mainstem. Well-developed upstream plug bar formation precluded the entrainment of coarser bedload into the abandoned channel, while Salinas River mouth conditions (open/closed) in conjunction with tidal and storm surge conditions may play a role in influencing the delivery of coarser suspended load fractions. Channel adjacent sediment deposition can be valuable records of hydro-meteorological and sedimentological regimes, but local depositional settings may dominate the character of short term (interdecadal) signatures.

  14. A social work study on family patterns and street children

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Iravani

    2014-06-01

    Full Text Available This paper presents a social work study on relationship between various family characteristics and street children in rural area as well as city of Esfahan, Iran. The proposed study selects a sample of 150 street children, 75 from city and 75 from rural area, and using some statistical tests verifies the effects of three factors including family income, place of residency and family size on street children. The results indicate that the city residence had more street children than rural residence did. In addition, there was a meaningful difference between the number of street children in low-income families and high-income families. Finally, the survey results indicate that big size families more likely suffered from street children than low size families did.

  15. Diversity of contexts in drug use among street adolescents.

    Science.gov (United States)

    Goncalves de Moura, Yone; van der Meer Sanchez, Zila; Noto, Ana Regina

    2010-09-01

    In this study we aimed to investigate through ethnographic methods the different contexts of drug use by street adolescents in Sao Paulo, Brazil. Participant observations and semistructured interviews were performed at 11 major points of adolescent concentration in the streets of the city and in 10 care institutions. The sample was composed of 17 adolescents between 12 and 17 years of age. Data showed diverse patterns of drug use distributed by geographic situation and street circumstances. Observations were grouped into three main contexts: (a) immersion: greater intensity of drug use associated with greater involvement in the street culture; (b) surface: less drug use associated with family closeness; and (c) alternative-migratory: greater involvement with drug trafficking and prostitution associated with less family closeness and street culture. The drug use patterns varied in accordance with the diversity of street situations. Therefore, the peculiarities of each context should be taken into consideration in the development of social/ health policies.

  16. [Street social education: historical, political and pedagogical bases].

    Science.gov (United States)

    de Oliveira, Walter Ferreira

    2007-01-01

    This work is about street social education as a pedagogical system that started in Latin America in the late 1970s, as the street population formed mostly by children and adolescents called for attention. The first street social educators were 'pastoral' agents working at the praça da Sé a place with large numbers of street children in São Paulo. Based on the Liberation Theology and on the pedagogies developed by Paulo Freire, Celestine Freinet, Anton Makarenko, and Emília Ferreiro, the street educators developed a conceptual field and participated in the promulgation of the 1988 Federal Constitution, particularly by writing and introducing the 'Estatuto da Criança e do Adolescente' (the 'Child and Adolescent Statute'). Street social education is currently latent and suffering the consequences of program discontinuity caused by successive changes of government. It is, therefore important to know the conceptual proposals.

  17. Whose Bay Street? Competing Narratives of Nassau's City Centre

    Directory of Open Access Journals (Sweden)

    Nona Patara Martin

    2009-05-01

    Full Text Available Bay Street has always been at the centre of commercial, cultural and political life in the Bahama Islands. It also acts as a gateway for millions of tourists who come to Nassau, the Bahamian capital, via cruise ships every year. Not surprisingly, Bahamians and non-Bahamians have widely divergent impressions of Bay Street. The need to accommodate the tourists who are critical to the Bahamian economy has meant that Bay Street, despite its deep social significance for Bahamians, has increasingly become a tourist space. With reference to the ‘sense of place’ and place attachment literature, this paper traces the transformation of Bay Street and attempts to tease out the most obvious tensions between the Bay Street that Bahamians experience and Bay Street as a port of call.

  18. Quantification of Gravel Rural Road Sediment Production

    Science.gov (United States)

    Silliman, B. A.; Myers Toman, E.

    2014-12-01

    Unbound rural roads are thought to be one of the largest anthropogenic sources of sediment reaching stream channels in small watersheds. This sediment deposition can reduce water quality in the streams negatively impacting aquatic habitat as well as impacting municipal drinking water sources. These roads are thought to see an increase in construction and use in southeast Ohio due to the expansion of shale gas development in the region. This study set out to quantify the amount of sediment these rural roads are able to produce. A controlled rain event of 12.7 millimeters of rain over a half hour period was used to drive sediment production over a 0.03 kilometer section of gravel rural road. These 8 segments varied in many characteristics and produced from 2.0 to 8.4 kilograms of sediment per 0.03 kilometers of road with the average production over the 8 segments being 5.5 kilograms of sediment. Sediment production was not strongly correlated with road segment slope but traffic was found to increase sediment production from 1.1 to 3.9 times as much sediment after traffic use. These results will help inform watershed scale sediment budgeting, and inform best management practices for road maintenance and construction. This study also adds to the understanding of the impacts of rural road use and construction associated with the changing land use from agricultural to natural gas extraction.

  19. Analysing the Cenozoic depositional record

    DEFF Research Database (Denmark)

    Goledowski, Bartosz; Clausen, O.R.; Nielsen, S.B.

    2008-01-01

    It is well known that sediment deposition in the North Sea and on the Norwegian Shelf varied significantly during the Cenozoic as a consequence of varying erosion rate mainly in Western Scandinavia, in Scotland and in the Alps. Recent results have demonstrated that a causal relationship exists...... of variations in erosion rates. Here we present the rationale behind the project, the data available and some preliminary results. The dense seismic and well coverage in the area makes it possible to estimate the rate of deposition of matrix mass. Assuming that sediment storage is not important, this provides...... models. The matrix mass deposition history will be compared with the paleoclimate record (e.g. oxygen isotope curves) to see if the previously observed correlation in the eastern North Sea can be extended to other ages and locations.  ...

  20. The on-street parking premium and car drivers' choice between street and garage parking

    NARCIS (Netherlands)

    Kobus, M.B.W.; Gutierrez Puigarnau, E.; Rietveld, P.; van Ommeren, J.N.

    2013-01-01

    We introduce a methodology to estimate the effect of parking prices on car drivers' choice between street and garage parking. Our key identifying assumption is that the marginal benefit of parking duration does not depend on this choice. The endogeneity of parking duration is acknowledged in the

  1. The Ballet of the Streets: Teaching about Cities at Street Level

    Science.gov (United States)

    McGuire, Patrick A.; Spates, James L.

    2011-01-01

    The urban scholar Jane Jacobs once described city life as "the ballet of the streets." In more than a quarter century of joint teaching, the authors have used Jacobs' metaphor to help their students understand that cities are living organisms created and maintained, for good or ill, by the people who live and work in them. At heart their…

  2. [Addictive behavior of street children: interculturation and resilience].

    Science.gov (United States)

    Kommegne, T; Denoux, P; Bernoussi, A; Njiengwe, E F

    2014-09-01

    This research belongs to a more comprehensive study on the care of street children in Cameroon. The idea is to develop an analysis of the street pathology where symptoms such as addictive behavior and drug addiction can be found. Beside HIV AIDS, addictive behaviors are the main risk factors that many professionals have to face with while dealing with the street problems today. Through an intercultural approach, we examined the practices of addictive typology, their initiatory role and their function in the integration of the street system. We also analysed their importance in the survival strategies. After an overview of theoretical controversies that feed the debate on addictions, we questioned the impact of these practices on the street career through the prism of general theory of addictions, particularly the hedonic management model. Addiction helps to resist adversity, it helps to desist and then to begin a harmonious neo development despite the horrors of the street experience. We undertook a quantitative and qualitative study on a sample of 148 street children. We proposed to 128 of them a questionnaire focused on addictive behaviors and survival strategies in the street context. We notably evaluated the street career of 24 of them, using interviews and standardized tests to assess self-esteem (Coopersmith's SEI) frustration tolerance (Rosenweig's P-F) and self-efficacy (Sherer's SE Scale) in order to measure the impact of addictive behaviors on the resilience process. We found that the street career is essentially traumatic, and that addictive behaviors involving various integration strategies are strongly linked to the interculturation process through the identity strategies and the intercultural competences. Addiction itself is not significantly related to self-esteem issues but strongly impacts on self-efficacy and the ability to tolerate frustration. They allow the street children to withstand the street adversity but are a real obstacle to their

  3. Trees in the city: valuing street trees in Portland, Oregon

    Science.gov (United States)

    G.H. Donovan; D.T. Butry

    2010-01-01

    We use a hedonic price model to simultaneously estimate the effects of street trees on the sales price and the time-on-market (TOM) of houses in Portland. Oregon. On average, street trees add $8,870 to sales price and reduce TOM by 1.7 days. In addition, we found that the benefits of street trees spill over to neighboring houses. Because the provision and maintenance...

  4. Playing With the City: Street Art and Videogames

    OpenAIRE

    Vazques Marquez, Israel; Pajares Tosca, Susana

    2017-01-01

    In this paper we introduce and describe the phenomenon of videogame street art as a specific kind of street art. We consider its materiality and significance, and conceptualize it in the light of a double manifestation of play: the playful appropriation of the city by the artist and the fact that street art encapsulates the act of playing videogames in a visual form. Digital play spills out of our computer screens and occupies the urban space with the explicit intention of involving spectator...

  5. Dating floodplain sediments using tree-ring response to burial

    Science.gov (United States)

    Friedman, J.M.; Vincent, K.R.; Shafroth, P.B.

    2005-01-01

    Floodplain sediments can be dated precisely based on the change in anatomy of tree rings upon burial. When a stem of tamarisk (Tamarix ramosissima) or sandbar willow (Salix exigua) is buried, subsequent annual rings in the buried section resemble the rings of roots: rings become narrower, vessels within the rings become larger, and transitions between rings become less distinct. We combined observations of these changes with tree-ring counts to determine the year of deposition of sedimentary beds exposed in a 150-m-long trench across the floodplain of the Rio Puerco, a rapidly filling arroyo in New Mexico. This method reliably dated most beds thicker than about 30 cm to within a year of deposition. Floodplain aggradation rates varied dramatically through time and space. Sediment deposition was mostly limited to brief overbank flows occurring every few years. The most rapid deposition occurred on channel-margin levees, which migrated laterally during channel narrowing. At the decadal timescale, the cross-section-average sediment deposition rate was steady, but there was a shift in the spatial pattern of deposition in the 1980s. From 1936 to 1986, sediment deposition occurred by channel narrowing, with little change in elevation of the thalweg. After 1986 sediment deposition occurred by vertical aggradation. From 1936 to 2000 about 27 per cent of the arroyo cross-section filled with sediment. The rate of filling from 1962 to 2000 was 0·8 vertical m/decade or 85 m2/decade.

  6. Effects of hurricanes Katrina and Rita on the chemistry of bottom sediments in Lake Pontchartrain, Louisiana, USA

    Science.gov (United States)

    Van Metre, P.C.; Horowitz, A.J.; Mahler, B.J.; Foreman, W.T.; Fuller, C.C.; Burkhardt, M.R.; Elrick, K.A.; Furlong, E.T.; Skrobialowski, S.C.; Smith, J.J.; Wilson, J.T.; Zaugg, S.D.

    2006-01-01

    The effects of Hurricanes Katrina and Rita and the subsequent unwatering of New Orleans, Louisiana, on the sediment chemistry of Lake Pontchartrain were evaluated by chemical analysis of samples of street mud and suspended and bottom sediments. The highest concentrations of urban-related elements and compounds (e.g., Pb, Zn, polycyclic aromatic hydrocarbons, and chlordane) in bottom sediments exceeded median concentrations in U.S. urban lakes and sediment-quality guidelines. The extent of the elevated concentrations was limited, however, to within a few hundred meters of the mouth of the 17th Street Canal, similar to results of historical assessments. Chemical and radionuclide analysis of pre- and post-Hurricane Rita samples indicates that remobilization of near-shore sediment by lake currents and storms is an ongoing process. The effects of Hurricanes Katrina and Rita on the sediment chemistry of Lake Pontchartrain are limited spatially and are most likely transitory. ?? 2006 American Chemical Society.

  7. On the escape of pollutants from urban street canyons

    Energy Technology Data Exchange (ETDEWEB)

    Baik, J.J.; Kim, J.J. [Kwangju Inst. of Science and Technology (Korea). Dept. of Environmental Science and Engineering

    2002-07-01

    Pollutant transport from urban street canyons is numerically investigated using a two-dimensional flow and dispersion model. The ambient wind blows perpendicular to the street and passive pollutants are released at the street level. Results from the control experiment with a street aspect ratio of 1 show that at the roof level of the street canyon, the vertical turbulent flux of pollutants is upward everywhere and the vertical flux of pollutants by mean flow is upward or downward. The horizontally integrated vertical flux of pollutants by mean flow at the roof level of the street canyon is downward and its magnitude is much smaller than that by turbulent process. These results indicate that pollutants escape from the street canyon mainly by turbulent process and that the net effect of mean flow is to make some escaped pollutants reenter the street canyon. Further experiments with different inflow turbulence intensities, inflow wind speeds, and street aspect ratio confirm the findings from the control experiment. In the case of two isolated buildings, the horizontally integrated vertical flux of pollutants by mean flow is upward due to flow separation but the other main results are the same as those from the control experiment. (author)

  8. [Street Outreach Offices: visibility, invisibility, and enhanced visibility].

    Science.gov (United States)

    Hallais, Janaína Alves da Silveira; Barros, Nelson Filice de

    2015-07-01

    This article discusses care for street people from a socio-anthropological perspective, using participant observation conducted with a team from a street outreach project. Based on observations, street people are historically viewed as marginal and rarely obtain access to health services, thus making them invisible to the Brazilian Unified National Health System. Brazil's National Policy for the Homeless provides for their access to health care, but such care is not always guaranteed in practice, because health services and professionals have little experience in dealing with homeless persons. The study concludes that enhanced visibility is needed to ensure care for people living on the street, establishing a therapeutic bond that deconstructs stigmatizing practice.

  9. Into a Mapping of Copenhagen Street Lighting 2014

    DEFF Research Database (Denmark)

    Bülow, Katja; Asp, Claus; Kongshaug, Jesper

    LED lighting is a new lighting component in urban Spaces. How does LED lighting change the visual experience of a street, how did it use to be and how will it become? The book presents a mapping method in which an overview map of light sources in the Copenhagen streets is combined with a video...... recording and a series of photos from a route, whick goes through different city parts and types of streets. The mapping is done in the crucial changing fase, in which the street lighting in Copenhagen is a mix of previously used light sources and LED....

  10. Smart street lighting : The advantages of LED street lighting and a smart control system in Uppsala municipality

    OpenAIRE

    Sjöberg, Inga; Gidén Hember, Amanda; Wallerström, Carolina

    2017-01-01

    The purpose of this bachelor thesis is to examine how LED street lights and a smart street light control system can reduce the energy consumption, costs and in extension the CO2 equivalents in a geographically delimited area. In 2015 the municipality of Sala installed LED armatures connected to a smart control system in the whole municipality. The smart control system enables for instance adjustment of the light intensity at specific times during the day and a supervision of the street light ...

  11. Rare earth elements in street dust and associated health risk in a municipal industrial base of central China.

    Science.gov (United States)

    Sun, Guangyi; Li, Zhonggen; Liu, Ting; Chen, Ji; Wu, Tingting; Feng, Xinbin

    2017-12-01

    The content levels, distribution characteristics, and health risks associated with 15 rare earth elements (REEs) in urban street dust from an industrial city, Zhuzhou, in central China were investigated. The total REE content (∑REE) ranged from 66.1 to 237.4 mg kg -1 , with an average of 115.9 mg kg -1 , which is lower than that of Chinese background soil and Yangtze river sediment. Average content of the individual REE in street dust decreased in the order Ce > La > Nd > Y > Pr > Sm > Gd > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The chondrite-normalized REE pattern indicated light REE (LREE) enrichment, a relatively steep LREE trend, heavy REE (HREE) depletion, a flat HREE trend, a Eu-negative anomaly and a Ce-positive anomaly. Foremost heavy local soil and to less degree anthropogenic pollution are the main sources of REE present in street dust. Health risk associated with the exposure of REE in street dust was assessed based on the carcinogenic and non-carcinogenic effect and lifetime average daily dose. The obtained cancer and non-cancer risk values prompt for no augmented health hazard. However, children had greater health risks than that of adults.

  12. Simulating the impacts of on-street vehicle parking on traffic operations on urban streets using cellular automation

    Science.gov (United States)

    Chen, Jingxu; Li, Zhibin; Jiang, Hang; Zhu, Senlai; Wang, Wei

    2017-02-01

    In recent years, many bicycle lanes on urban streets are replaced with vehicle parking places. Spaces for bicycle riding are reduced, resulting in changes in bicycle and vehicle operational features. The objective of this study is to estimate the impacts of on-street parking on heterogeneous traffic operation on urban streets. A cellular automaton (CA) model is developed and calibrated to simulate bicycle lane-changing on streets with on-street parking. Two types of street segments with different bicycle lane width are considered. From the simulation, two types of conflicts between bicycles and vehicles are identified which are frictional conflicts and blocking conflicts. Factors affecting the frequency of conflicts are also identified. Based on the results, vehicle delay is estimated for various traffic situations considering the range of occupancy levels for on-street parking. Later, a numerical network example is analyzed to estimate the network impact of on-street parking on traffic assignment and operation. Findings of the study are helpful to policies and design regarding on-street vehicle parking to improve the efficiency of traffic operations.

  13. Air quality considerations for stormwater green street design

    International Nuclear Information System (INIS)

    Shaneyfelt, Kathryn M.; Anderson, Andrew R.; Kumar, Prashant; Hunt, William F.

    2017-01-01

    Green streets are increasingly being used as a stormwater management strategy to mitigate stormwater runoff at its source while providing other environmental and societal benefits, including connecting pedestrians to the street. Simultaneously, human exposure to particulate matter from urban transportation is of major concern worldwide due to the proximity of pedestrians, drivers, and cyclists to the emission sources. Vegetation used for stormwater treatment can help designers limit the exposure of people to air pollutants. This goal can be achieved through the deliberate placement of green streets, along with strategic planting schemes that maximize pollutant dispersion. This communication presents general design considerations for green streets that combine stormwater management and air quality goals. There is currently limited guidance on designing green streets for air quality considerations; this is the first communication to offer suggestions and advice for the design of green stormwater streets in regards to their effects on air quality. Street characteristics including (1) the width to height ratio of the street to the buildings, (2) the type of trees and their location, and (3) any prevailing winds can have an impact on pollutant concentrations within the street and along sidewalks. Vegetation within stormwater control measures has the ability to reduce particulate matter concentrations; however, it must be carefully selected and placed within the green street to promote the dispersion of air flow. - Highlights: • Green streets can be used for both stormwater and air quality management. • Design considerations must be made to minimize human exposure to air pollutants. • Urban vegetation can improve air quality with careful selection and placement.

  14. Street Choice Logit Model for Visitors in Shopping Districts

    Directory of Open Access Journals (Sweden)

    Ko Kawada

    2014-07-01

    Full Text Available In this study, we propose two models for predicting people’s activity. The first model is the pedestrian distribution prediction (or postdiction model by multiple regression analysis using space syntax indices of urban fabric and people distribution data obtained from a field survey. The second model is a street choice model for visitors using multinomial logit model. We performed a questionnaire survey on the field to investigate the strolling routes of 46 visitors and obtained a total of 1211 street choices in their routes. We proposed a utility function, sum of weighted space syntax indices, and other indices, and estimated the parameters for weights on the basis of maximum likelihood. These models consider both street networks, distance from destination, direction of the street choice and other spatial compositions (numbers of pedestrians, cars, shops, and elevation. The first model explains the characteristics of the street where many people tend to walk or stay. The second model explains the mechanism underlying the street choice of visitors and clarifies the differences in the weights of street choice parameters among the various attributes, such as gender, existence of destinations, number of people, etc. For all the attributes considered, the influences of DISTANCE and DIRECTION are strong. On the other hand, the influences of Int.V, SHOPS, CARS, ELEVATION, and WIDTH are different for each attribute. People with defined destinations tend to choose streets that “have more shops, and are wider and lower”. In contrast, people with undefined destinations tend to choose streets of high Int.V. The choice of males is affected by Int.V, SHOPS, WIDTH (positive and CARS (negative. Females prefer streets that have many shops, and couples tend to choose downhill streets. The behavior of individual persons is affected by all variables. The behavior of people visiting in groups is affected by SHOP and WIDTH (positive.

  15. Street Choice Logit Model for Visitors in Shopping Districts

    Science.gov (United States)

    Kawada, Ko; Yamada, Takashi; Kishimoto, Tatsuya

    2014-01-01

    In this study, we propose two models for predicting people’s activity. The first model is the pedestrian distribution prediction (or postdiction) model by multiple regression analysis using space syntax indices of urban fabric and people distribution data obtained from a field survey. The second model is a street choice model for visitors using multinomial logit model. We performed a questionnaire survey on the field to investigate the strolling routes of 46 visitors and obtained a total of 1211 street choices in their routes. We proposed a utility function, sum of weighted space syntax indices, and other indices, and estimated the parameters for weights on the basis of maximum likelihood. These models consider both street networks, distance from destination, direction of the street choice and other spatial compositions (numbers of pedestrians, cars, shops, and elevation). The first model explains the characteristics of the street where many people tend to walk or stay. The second model explains the mechanism underlying the street choice of visitors and clarifies the differences in the weights of street choice parameters among the various attributes, such as gender, existence of destinations, number of people, etc. For all the attributes considered, the influences of DISTANCE and DIRECTION are strong. On the other hand, the influences of Int.V, SHOPS, CARS, ELEVATION, and WIDTH are different for each attribute. People with defined destinations tend to choose streets that “have more shops, and are wider and lower”. In contrast, people with undefined destinations tend to choose streets of high Int.V. The choice of males is affected by Int.V, SHOPS, WIDTH (positive) and CARS (negative). Females prefer streets that have many shops, and couples tend to choose downhill streets. The behavior of individual persons is affected by all variables. The behavior of people visiting in groups is affected by SHOP and WIDTH (positive). PMID:25379274

  16. Health policy making for street children: challenges and strategies.

    Science.gov (United States)

    Abdi, Fatemeh; Saeieh, Sara Esmaelzadeh; Roozbeh, Nasibeh; Yazdkhasti, Mansoureh

    2017-08-17

    Background The phenomenon of street children is a bio-psychological and social issue that not only harms children, but also endangers the health of a society. In line with the national programs for the development and promotion of street children's health in Iran, health policy making and essential strategies for this group of children will be presented in this paper. This paper will discuss the main issues and challenges of street children's health and, also, health policy and guidelines for this population. Methods In this review study, the keywords; street children, health, challenges, policy, and health policy making were searched through PubMed, SID, Iranmedex, World Health Organization (WHO), Emro, the Cochran Library, Medline and Google scholar to collect data. The search resulted in 84 related resources from which 48 cases that were more relevant to this research and covered the issue more comprehensively, were used. All data published during 2002-2015 have been included in this paper. Results Key concepts including street children and their health, health policy, strategies to improve the health of street children, health policy approaches for street children, the WHO's strategies, and social support program for street children must be considered in the health policy making processes for street children, as precise identification of the relevant information makes planning more effective in health policy making for this group of children. Conclusion The phenomenon of street children is a growing problem in the world and it has turned into a serious concern in many countries including Iran. The findings of this study can be used for identifying necessary measures in order to use research outcomes more effectively in policy making processes and reforming street children's health policies in Iran.

  17. Early diagenesis in the Congo deep-sea fan sediments dominated by massive terrigenous deposits: Part I - Oxygen consumption and organic carbon mineralization using a micro-electrode approach

    Science.gov (United States)

    Pozzato, Lara; Cathalot, Cécile; Berrached, Chabha; Toussaint, Flora; Stetten, Elsa; Caprais, Jean-Claude; Pastor, Lucie; Olu, Karine; Rabouille, Christophe

    2017-08-01

    Organic matter (OM) transfer from the continent to the ocean occurs across margins which constitute a major area of OM recycling and burial. The lobe complex of the Congo deep-sea fan is connected to the river mouth by a canyon and alimented by recurrent turbidity currents, containing a large proportion of labile terrigenous OM and producing high sedimentation rates. These inputs support the development of ecosystems harboring rich assemblages of vesicomyid bivalves and bacterial mats, called Habitats. Here, we present O2 microprofiles and diffusive oxygen uptake rates (DOUs) obtained during the CONGOLOBE project at six sites of this active lobe complex by in situ and on-board methods based on micro-electrode profiling. The dataset is used to determine remineralization rates and study the biogeochemical dynamics of different ecosystems of the lobe area, in order to compare levee and background sediments to the Habitats developed on the flanks of the main turbiditic channel. Levee and background sediments are characterized by significantly higher DOUs than abyssal sediments at 5000 m meters depth (2-5 mmol O2 m-2 d-1versus 1.5-2.5 mmol O2 m-2 d-1) and the Habitats are hotspots of OM remineralization with DOU values ranging between 8 and 40 mmol O2 m-2 d-1. By comparing sites near the active channel to a site located 50 km away, we show that the lobe connection to the main turbiditic channel is vital to the dense benthic communities.

  18. Numerical simulation of mechanical compaction of deepwater shallow sediments

    Science.gov (United States)

    Sun, Jin; Wu, Shiguo; Deng, Jingen; Lin, Hai; Zhang, Hanyu; Wang, Jiliang; Gao, Jinwei

    2018-02-01

    To study the compaction law and overpressure evolution in deepwater shallow sediments, a large-strain compaction model that considers material nonlinearity and moving boundary is formulated. The model considers the dependence of permeability and material properties on void ratio. The modified Cam-Clay model is selected as the constitutive relations of the sediments, and the deactivation/reactivation method is used to capture the moving top surface during the deposition process. A one-dimensional model is used to study the compaction law of the shallow sediments. Results show that the settlement of the shallow sediments is large under their own weight during compaction. The void ratio decreases strictly with burial depth and decreases more quickly near the seafloor than in the deeper layers. The generation of abnormal pressure in the shallow flow sands is closely related to the compaction law of shallow sediments. The two main factors that affect the generation of overpressure in the sands are deposition rate and permeability of overlying clay sediments. Overpressure increases with an increase in deposition rate and a decrease in the permeability of the overlying clay sediment. Moreover, an upper limit for the overpressure exists. A two-dimensional model is used to study the differential compaction of the shallow sediments. The pore pressure will still increase due to the inflow of the pore fluid from the neighboring clay sediment even though the deposition process is interrupted.

  19. {sup 210}Pb-Excess and Sediment Accumulation Rates at the Iberian Continental Margin

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, F. P.; Oliveira, J. M.; Soares, A. M. [Nuclear and Technological Institute, Sacavem (Portugal)

    2013-07-15

    Sediments from the continental shelf, slope, and rise at the continental margin of northern Portugal and the adjacent Iberian abyssal basin were analysed for 210Pb, {sup 226}Ra, {sup 137}Cs and {sup 14}C. Pb-210 derived sedimentation rates at the continental shelf off the Portuguese coast were 0.2-0.6 cm/a. In some cores from fine sediment deposits at the outer shelf, the {sup 210}Pb excess continuum was interrupted and sediment layers were missing, suggesting that events such as sediment slides could have occurred. Higher sedimentation rates were determined in locations at the rise of the continental slope, confirming enhanced deposition by sediment slides. In the deeper Iberian Abyssal Basin, using the {sup 14}C age of sediment layers the sedimentation rate was determined at 3.2 cm/ka, thus four orders of magnitude lower than at the continental shelf. The spatial distribution of sedimentation rates determined by radionuclide based chronologies, suggested that fine sediments from river discharges are deposited mainly at the outer continental shelf. These deposits may became unstable with time and, occasionally, originate sediment slides that are drained by the canyons and reach the deep sea. The Iberian abyssal basin receives some advective contribution of these sediment slides and the sedimentation rate is one order of magnitude higher than in other abyssal basins of the NE Atlantic Ocean. (author)

  20. To what extent can intracrater layered deposits that lack clear sedimentary textures be used to infer depositional environments?

    Science.gov (United States)

    Cadieux, Sarah B.; Kah, Linda C.

    2015-03-01

    Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata showing systematic alternation between slope- and cliff-forming units, suggesting either rhythmic deposition of distinct lithologies or similar lithologies that experienced differential cementation. On Earth, rhythmically deposited strata can be examined in terms of stratal packaging, wherein the interplay of tectonics, sediment deposition, and base level (i.e., the position above which sediment accumulation is expected to be temporary) result in changes in the amount of space available for sediment accumulation. These predictable patterns of sediment deposition can be used to infer changes in basin accommodation regardless of the mechanism of deposition (e.g. fluvial, lacustrine, or aeolian). Here, we analyze sedimentary deposits from three craters (Becquerel Crater, Danielson Crater, Crater A) in Arabia Terra. Each crater contains layered deposits that are clearly observed in orbital images. Although orbital images are insufficient to specifically determine the origin of sedimentary deposits, depositional couplets can be interpreted in terms of potential accommodation space available for deposition, and changes in the distribution of couplet thickness through stratigraphy can be interpreted in terms of changing base level and the production of new accommodation space. Differences in stratal packaging in these three craters suggest varying relationships between sedimentary influx, sedimentary base level, and concomitant changes in accommodation space. Previous groundwater upwelling models hypothesize that layered sedimentary deposits were deposited under warm climate conditions of early Mars. Here, we use observed stacking patterns to propose a model for deposition under cold climate conditions, wherein episodic melting of ground ice could raise local base level, stabilize sediment deposition, and result in differential cementation of accumulated strata. Such analysis demonstrates that

  1. Lime stabilization of fine-grained sediments in western Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Ingeman-Nielsen, Thomas; Skels, Peteris

    2011-01-01

    Thick deposits of fine-grained marine sediments exist in large areas of western Greenland. Many places these sediments are located above sea-level, and now complicate construction projects in urban areas. The mineralogy of the fine-grained sediments is very different from European sediments, mainly...... due to the cold climate, and it is therefore of great interest to study possible methods to improve the stability and strength properties. This project includes laboratory studies of lime stabilization on fine-grained marine sediments from Kangerlussuaq, western Greenland. The results have included...

  2. Politicians, Managers, and Street-Level Bureaucrats

    DEFF Research Database (Denmark)

    May, Peter J.; Winter, Søren

    2012-01-01

    This article addresses the influence of politicians, managers, and the dispositions of street level bureaucrats in shaping actions at the frontlines of policy implementation. We investigate these for the implementation of employment policy reforms in Denmark. Our findings show a large percentage...... of caseworkers emphasizing actions that are consistent with thenational employment reform goal of getting clients into jobs quickly. The influence of politicians and managers in bringing this about is relatively limited in comparison to the influences of caseworkers’ understanding of policy goals......, their professional knowledge, and their policy predispositions. Our main contribution is an unpacking of the political and managerial influences on caseworkers’ policy emphases. We find direct effects and, more notably, indirect effects that operate on the influence of caseworkers’ perceptions of policy goals...

  3. The digital evolution of occupy wall street.

    Science.gov (United States)

    Conover, Michael D; Ferrara, Emilio; Menczer, Filippo; Flammini, Alessandro

    2013-01-01

    We examine the temporal evolution of digital communication activity relating to the American anti-capitalist movement Occupy Wall Street. Using a high-volume sample from the microblogging site Twitter, we investigate changes in Occupy participant engagement, interests, and social connectivity over a fifteen month period starting three months prior to the movement's first protest action. The results of this analysis indicate that, on Twitter, the Occupy movement tended to elicit participation from a set of highly interconnected users with pre-existing interests in domestic politics and foreign social movements. These users, while highly vocal in the months immediately following the birth of the movement, appear to have lost interest in Occupy related communication over the remainder of the study period.

  4. Technology transfer, a two-way street

    International Nuclear Information System (INIS)

    Martin, H.L.

    1994-01-01

    Technology transfer through the Pollution Prevention ampersand Control Conferences, which have been cosponsored by the Environmental Protection Agency and by the professional societies of industry, greatly improved the environmental projects of the Department of Energy at Savannah River Site (SRS) in the mid-1980's. Those technologies, used in the liquid effluent treatment of the metal finishing liquid effluents from aluminum cleaning and nickel plating of fuel and targets for the nuclear production reactors, have been enhanced by the research and development of SRS engineers and scientists. The technology transfer has now become a two-way street to the benefit of our Nation's environment as these enhancements are being adopted in the metal finishing industry. These success stories are examples of the achievements anticipated in the 1990's as technology development in the federal facilities is shared with commercial industry

  5. The digital evolution of occupy wall street.

    Directory of Open Access Journals (Sweden)

    Michael D Conover

    Full Text Available We examine the temporal evolution of digital communication activity relating to the American anti-capitalist movement Occupy Wall Street. Using a high-volume sample from the microblogging site Twitter, we investigate changes in Occupy participant engagement, interests, and social connectivity over a fifteen month period starting three months prior to the movement's first protest action. The results of this analysis indicate that, on Twitter, the Occupy movement tended to elicit participation from a set of highly interconnected users with pre-existing interests in domestic politics and foreign social movements. These users, while highly vocal in the months immediately following the birth of the movement, appear to have lost interest in Occupy related communication over the remainder of the study period.

  6. Introduction. Street Art: Iconoclasm and Institutionalization

    Directory of Open Access Journals (Sweden)

    Cinzia Bianchi

    2017-09-01

    Full Text Available On the night of May 12, 2016 the street artist Blu, armed with a roller and some grey paint, set out to paint over all the works he had done in the city of Bologna. In this intent, the following day also, he was helped by activists from the community centers, his own collaborators and ordinary citizens united in an informal community that upheld his cause. Many others gathered either to celebrate this rite of destruction or to complain in disbelief, but in any case, to watch as it happened. Attention centered particularly on #OccupyMordor, a large mural that dominated the XM24 (an occupied social community center in the Bolognina district which had previously been a focus when citizens mobilized to protect it from new building projects that envisaged the destruction of the building (July 2013.

  7. Sediment isotope tomography (SIT) model version 1

    International Nuclear Information System (INIS)

    Carroll, J.; Abraham, J.D.

    1996-01-01

    Geochronology using 210 Pb is the principal method used to quantify sediment accumulation in rapidly depositing aquatic environments such as lakes, estuaries, continental shelves, and submarine canyons. This method is based on the radioactive decay of 210 Pb with depth in a column of sediment. The decay through time of 210 Pb P(t) is governed by the exponential law P(t) = P 0 exp( -λt) where P 0 is the surficial concentration at time t = 0, and λ is the decay constant (3.114 sm-bullet 10 -2 year [yr] -1 for 210 Pb). If the sedimentation rate is constant, then elapsed time t is connected to burial depth x, through x = Vt where V is the sedimentation velocity. Accordingly, P(x) = P 0 exp( -λx/V). The sedimentation velocity is obtained from an exponential fit to the measured 210 Pb data P(x), with depth x

  8. Road dust emission sources and assessment of street washing effect

    NARCIS (Netherlands)

    Karanasiou, A.; Amato, F.; Moreno, T.; Lumbreras, J.; Borge, R.; Linares, C.; Boldo, E.; Alastuey, A.; Querol, X.

    2014-01-01

    Although previous studies report on the effect of street washing on ambient particulate matter levels, there is a lack of studies investigating the results of street washing on the emission strength of road dust. A sampling campaign was conducted in Madrid urban area during July 2009 where road dust

  9. Do urban canyons influence street level grass pollen concentrations?

    DEFF Research Database (Denmark)

    Peel, Robert George; Kennedy, Roy; Smith, Matt

    2014-01-01

    In epidemiological studies, outdoor exposure to pollen is typically estimated using rooftop monitoring station data, whilst exposure overwhelmingly occurs at street level. In this study the relationship between street level and roof level grass pollen concentrations was investigated for city cent...

  10. INTRODUCTION The term street children has many definitions in ...

    African Journals Online (AJOL)

    this, the still schooling street children in this study may likely have gravitated to the streets due to the lack of recreational facilities to keep youths occupied after school hours in the rural areas. As at the time of study, no amusement parks, cinemas and other recreational places exists in the Local Government Area. It is known.

  11. Bacterial contamination of street vending food in Kumasi, Ghana ...

    African Journals Online (AJOL)

    Street vending foods are readily available sources of meals for many people but the biological safe-ty of such food is always in doubt. The aim of this study is to ascertain bacterial isolate and deter-mine total counts of bacterial species responsible for the contamination of the street vending food in Kumasi so as to determine ...

  12. Adolescent Street Boy Urchins and Vocational Training in Northern Nigeria

    Science.gov (United States)

    Usman, Lantana M.

    2009-01-01

    In northern Nigeria, over 80% of the unskilled and uneducated adolescent street boys, or "Almajiris", are from the ethnic Hausa-Fulani tribes. They depend on street begging and menial jobs for daily survival. In dealing with the situation, state vocational centers were established as the Millennium Hope Project (MHP) to provide the boys…

  13. Gender Differences in the Family Situation of Brazilian Street Youth.

    Science.gov (United States)

    Raffaelli, M.; Koller, S. H.; Reppold, C.; Kuschick, M.; Krum, F.; Bandeira, D.; Simoes, C.

    The goal of this analysis was to examine gender differences in the experiences of children and adolescents found on city streets. It has been proposed that girls who leave home to seek their survival on city streets are from more disturbed families than boys, reflecting cultural factors that result in differential norms for male and female…

  14. Green Street in District of Columbia Curbs Harmful Runoff

    Science.gov (United States)

    The name of the block hasn’t been changed to “Oh!” Street, but a revamped section of O Street NW in the District of Columbia is turning heads with green features that are keeping stormwater pollution out of the Anacostia River.

  15. HIV knowledge and sexual risk behavior among street adolescents ...

    African Journals Online (AJOL)

    HIV knowledge and sexual risk behavior among street adolescents in rehabilitation centres in Kinshasa; DRC: gender differences. ... Background: Street children, common in Africa, are increasingly vulnerable to alcohol and drugs of abuse and lack access to both healthcare and knowledge about HIV and AIDS. Hence, this ...

  16. Land Use Correlates of Street Children in Ogbomoso, Nigeria

    African Journals Online (AJOL)

    There exist many locations in which street children are found: public spheres such as markets, bus stops, car parks, garages, street corners, and under the bridges .... attributes of space such as form, pattern and aspect and are descriptive in ...

  17. 77 FR 67689 - Fidelity Aberdeen Street Trust, et al.;

    Science.gov (United States)

    2012-11-13

    ...] Fidelity Aberdeen Street Trust, et al.; Notice of Application November 6, 2012. AGENCY: Securities and... arrangements (``Prior Order'').\\1\\ \\1\\ Colchester Street Trust, et al., Investment Company Act Release Nos... Trust, et al., Investment Company Act Release Nos. 23787 (Apr. 15, 1999) (notice) and 23831 (May 11...

  18. A Semiotic Reading and Discourse Analysis of Postmodern Street Performance

    Science.gov (United States)

    Lee, Mimi Miyoung; Chung, Sheng Kuan

    2009-01-01

    Postmodern street art operates under a set of references that requires art educators and researchers to adopt alternative analytical frameworks in order to understand its meanings. In this article, we describe social semiotics, critical discourse analysis, and postmodern street performance as well as the relevance of the former two in interpreting…

  19. The Initiation of Homeless Youth into the Street Economy

    Science.gov (United States)

    Gwadz, Marya Viorst; Gostnell, Karla; Smolenski, Carol; Willis, Brian; Nish, David; Nolan, Theresa C.; Tharaken, Maya; Ritchie, Amanda S.

    2009-01-01

    Homeless youth (HY) who lack employment in the formal economy typically turn to the street economy (e.g., prostitution, drug selling) for survival. Guided by the theory of social control, the present paper explores factors influencing HY's initiation into the street economy. Eighty HY (ages 15-23) were recruited from four community-based…

  20. Hygiene practices among street food vendors in Tamale Metropolis ...

    African Journals Online (AJOL)

    The study noted that street food business in the Tamale Metropolis was women dominated (76%). Majority of vendors (78%) were aged 20-39 years. Public toilets (pit latrines) were accessible to all vending sites. Though high number of street food vendors had some form of formal education (66%) and knowledge of food ...

  1. Detecting Themed Streets Using a Location Based Service Application

    Directory of Open Access Journals (Sweden)

    Byeongsuk Ji

    2016-07-01

    Full Text Available Various themed streets have recently been developed by local governments in order to stimulate local economies and to establish the identity of the corresponding places. However, the motivations behind the development of some of these themed street projects has been based on profit, without full considerations of people’s perceptions of their local areas, resulting in marginal effects on the local economies concerned. In response to this issue, this study proposed a themed street clustering method to detect the themed streets of a specific region, focusing on the commercial themed street, which is more prevalent than other types of themed streets using location based service data. This study especially uses “the street segment” as a basic unit for analysis. The Sillim and Gangnam areas of Seoul, South Korea were chosen for the evaluation of the adequacy of the proposed method. By comparing trade areas that were sourced from a market analysis report by a reliable agent with the themed streets detected in this study, the experiment results showed high proficiency of the proposed method.

  2. Relationships as determinants of substance use amongst street ...

    African Journals Online (AJOL)

    Background: Unrestrained exposure to street life often makes the street child vulnerable to psychoactive substances. In other settings, the social relationships of the substance user with those around him or her and family norms of parenting have been docu-mented to modulate use. However, there is a dearth of literature on ...

  3. An Assessment of the Emerging Networks of Support for Street ...

    African Journals Online (AJOL)

    Nigeria, being asignatory to the Convention on the Rights of the Child (UNCRC, 1989) promulgated the Child Rights Act 2003, which aimed at ameliorating the condition of street children in Nigeria. In line with this, there are emerging networks of support for street children. The extent to which these support networks are ...

  4. Poverty alleviation from the perspective of street vendors in Lesoth ...

    African Journals Online (AJOL)

    The aim of this paper was to examine from the perspective of street vendors how they are fighting poverty and the extent of winning this endemic cankerworm. The findings of this paper are informed by a study carried in 2007 on poverty and street vendors in Lesotho. Questionnaires and focus group discussions were used ...

  5. Designing safe and inclusive streets in India | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-11-17

    Nov 17, 2016 ... In fast-growing Indian cities such as Ahmedabad, streets are also the site of conflict. ... while instances of violence against women are partly linked to land ... by poor street design, and to develop people-centred alternatives.

  6. Health problems of street children and women in Awassa, Southern ...

    African Journals Online (AJOL)

    Background: The number of street children and women in major towns of Ethiopia is rapidly increasing. Yet their problems have not been fully studied. Objective: To assess health and related problems in street children and women. Methods: A cross sectional survey was conducted in Awassa town, women southern ...

  7. Mathematical simulation of sediment and radionuclide transport in estuaries

    International Nuclear Information System (INIS)

    Onishi, Y.; Trent, D.S.

    1982-11-01

    The finite element model LFESCOT (Flow, Energy, Salinity, Sediment and Contaminant Transport Model) was synthesized under this study to simulate radionuclide transport in estuaries to obtain accurate radionuclide distributions which are affected by these factors: time variance, three-dimensional flow, temperature, salinity, and sediments. Because sediment transport and radionuclide adsorption/desorption depend strongly on sizes or types of sediments, FLESCOT simulates sediment and a sediment-sorbed radionuclide for the total of three sediment-size fractions (or sediment types) of both cohesive and noncohesive sediments. It also calculates changes of estuarine bed conditions, including bed elevation changes due to sediment erosion/deposition, and three-dimensional distributions of three bed sediment sizes and sediment-sorbed radionuclides within the bed. Although the model was synthesized for radionuclide transport, it is general enough to also handle other contaminants such as heavy metals, pesticides, or toxic chemicals. The model was checked for its capability for flow, water surface elevation change, salinity, sediment and radionuclide transport under various simple conditions first, confirming the general validity of the model's computational schemes. These tests also revealed that FLESCOT can use large aspect ratios of computational cells, which are necessary in handling long estuarine study areas. After these simple tests, FLESCOT was applied to the Hudson River estuary between Chelsea and the mouth of the river to examine how well the model can predict radionuclide transport through simulating tidally influenced three-dimensional flow, salinity, sediment and radionuclide movements with their interactions

  8. Quality Analysis of Open Street Map Data

    Science.gov (United States)

    Wang, M.; Li, Q.; Hu, Q.; Zhou, M.

    2013-05-01

    Crowd sourcing geographic data is an opensource geographic data which is contributed by lots of non-professionals and provided to the public. The typical crowd sourcing geographic data contains GPS track data like OpenStreetMap, collaborative map data like Wikimapia, social websites like Twitter and Facebook, POI signed by Jiepang user and so on. These data will provide canonical geographic information for pubic after treatment. As compared with conventional geographic data collection and update method, the crowd sourcing geographic data from the non-professional has characteristics or advantages of large data volume, high currency, abundance information and low cost and becomes a research hotspot of international geographic information science in the recent years. Large volume crowd sourcing geographic data with high currency provides a new solution for geospatial database updating while it need to solve the quality problem of crowd sourcing geographic data obtained from the non-professionals. In this paper, a quality analysis model for OpenStreetMap crowd sourcing geographic data is proposed. Firstly, a quality analysis framework is designed based on data characteristic analysis of OSM data. Secondly, a quality assessment model for OSM data by three different quality elements: completeness, thematic accuracy and positional accuracy is presented. Finally, take the OSM data of Wuhan for instance, the paper analyses and assesses the quality of OSM data with 2011 version of navigation map for reference. The result shows that the high-level roads and urban traffic network of OSM data has a high positional accuracy and completeness so that these OSM data can be used for updating of urban road network database.

  9. Street canyon aerosol pollutant transport measurements.

    Science.gov (United States)

    Longley, I D; Gallagher, M W; Dorsey, J R; Flynn, M; Bower, K N; Allan, J D

    2004-12-01

    Current understanding of dispersion in street canyons is largely derived from relatively simple dispersion models. Such models are increasingly used in planning and regulation capacities but are based upon a limited understanding of the transport of substances within a real canyon. In recent years, some efforts have been made to numerically model localised flow in idealised canyons (e.g., J. Appl. Meteorol. 38 (1999) 1576-89) and stepped canyons (Assimakopoulos V. Numerical modelling of dispersion of atmospheric pollution in and above urban canopies. PhD thesis, Imperial College, London, 2001) but field studies in real canyons are rare. To further such an understanding, a measurement campaign has been conducted in an asymmetric street canyon with busy one-way traffic in central Manchester in northern England. The eddy correlation method was used to determine fluxes of size-segregated accumulation mode aerosol. Measurements of aerosol at a static location were made concurrently with measurements on a platform lift giving vertical profiles. Size-segregated measurements of ultrafine and coarse particle concentrations were also made simultaneously at various heights. In addition, a small mobile system was used to make measurements of turbulence at various pavement locations within the canyon. From this data, various features of turbulent transport and dispersion in the canyon will be presented. The concentration and the ventilation fluxes of vehicle-related aerosol pollutants from the canyon will be related to controlling factors. The results will also be compared with citywide ventilation data from a separate measurement campaign conducted above the urban canopy.

  10. Biota-sediment accumulation factors for radionuclides and sediment associated biota of the Ottawa River

    Energy Technology Data Exchange (ETDEWEB)

    Rowan, D.; Silke, R.; Carr, J., E-mail: rowand@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2013-12-15

    As Ottawa River contamination is historical and resides in sediment, ecological risk and trophic transfer depend on linkages between sediment and biota. One of the ways in which this linkage is quantified is through the use of the biota sediment accumulation factor (BSAF). In this study, we present the first field estimates of BSAF for a number of radionuclides. The strongest and most consistent BSAFs were those for {sup 137}Cs in deposit feeding taxa, suggesting that sediment concentrations rather than dissolved concentrations drive uptake. For crayfish and unionid bivalves that do not feed on sediment, biota radionuclide concentrations were not related to sediment concentrations, but rather reflected concentrations in water. BSAFs would not be appropriate for these non-deposit feeding biota. BSAFs for {sup 137}Cs were not significantly different among deposit feeding taxa, suggesting similar processes for ingestion, assimilation and elimination. These data also show that the concentration factor approach used for guidance would have led to spurious results in this study for deposit feeding benthic invertebrates. Concentrations of {sup 137}Cs in Hexagenia downstream of the CRL process outfall range by about 2-orders of magnitude, in comparison to relatively uniform water concentrations. The concentration factor approach would have predicted a single value downstream of CRL, underestimating exposure to Hexagenia by almost 2-orders of magnitude at sites close to the CRL process outfall. (author)

  11. Plutonium and americium in Lake Michigan sediments

    International Nuclear Information System (INIS)

    Edgington, D.N.; Alberts, J.J.; Wahlgren, M.A.; Karttunen, J.O.; Reeve, C.A.

    1975-01-01

    The vertical distributions of 239 , 240 Pu, 238 Pu, and 137 Cs have been measured in sediment cores taken from Lake Michigan. Sections from a limited number of cores have been analyzed for 241 Am. In addition, grab samples from ten locations in the southern basin of the lake have been analyzed for phase distribution of 239 , 240 Pu using a sequential extraction technique. The results indicate that the 239 , 240 Pu, 238 Pu, and 137 Cs from weapons testing, and the 241 Am formed in situ are concentrated in the sediments. A comparison of the total deposition of 239 , 240 Pu and 137 Cs indicates that 137 Cs may be valuable as a monitor for 239 , 240 Pu deposition in the sediments. Values of the 238 Pu/ 239 , 240 Pu ratio are in agreement with values reported in Lake Ontario sediments (and Lake Michigan plankton) and show little variation with depth. 241 Am data support the concept of in situ production with little preferential mobility after formation. Studies of sedimentary phase distributions show that 239 , 240 Pu is associated with hydrous oxide phases which are chemically stable under the prevailing conditions in lake sediments. Since Lake Michigan sediments remain aerobic, relatively little 239 , 240 Pu is available for chemical mobilization from the hydrous oxide or organic phases present in the sediments

  12. The Education Rights of Street-Involved Children

    Directory of Open Access Journals (Sweden)

    Sonja Grover

    2010-05-01

    Full Text Available This paper provides an overview of certain key aspects of the practical and legal situation of street-involved children globally. The inadequate protection of these children under both domestic and international law is addressed. The diversity of the population of street-involved children is considered as is the fact that this group is composed of both legally stateless and de facto stateless children. The relationship of street involvement to child labor, various health risks and victimization is discussed. The educational needs of older street-involved children are addressed including their right to participate in decision-making regarding aspects of educational service design and delivery. The overall objective of this paper is to encourage those who are involved in, or could impact upon educational policy to include street-involved children in their educational planning implementation and advocacy efforts.

  13. The uranium ore deposits in Ciudad Rodrigo Phyllites. about the possibility of new deposits

    International Nuclear Information System (INIS)

    Mingarro Martin, E.; Marin Benavente, C.

    1969-01-01

    The main features of the genesis of uranium deposits of the Fe mine type, are discussed in this paper. Pitchblende ore is related with phyllites bearing organic material and with geomorphological level, fossilized by eocene sediments. As a result, new uranium ore deposits are possible under Ciudad Rodrigo tertiary basin, tertiary cover depth being little more than three hundred feet. (Author)

  14. Exogenous deposits

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1988-01-01

    Exogenous deposits forming as a result of complex exogenous processes, passed under the influence of outside forces on the Earth surface. To them relate physical and chemical weathering, decomposition and decay of mineral masses, redistribution and transportation of material, forming and deposit of new minerals and ores steady on the earth surface conditions

  15. Diffusion of Complete Streets policies Across US communities.

    Science.gov (United States)

    Moreland-Russell, Sarah; Eyler, Amy; Barbero, Colleen; Hipp, J Aaron; Walsh, Heidi

    2013-01-01

    Complete Streets policies guide planning in communities by making the transportation system accommodating to all users including vehicle drivers, pedestrians, and bicyclists, as well as those using public transportation. While the number of Complete Streets policies has increased over the past decade, no research has explored the factors attributing to the widespread diffusion of these policies. The purpose of this study was to apply concepts of the Diffusion of Innovation Theory to data related to Complete Streets policies in order to identify potential patterns and correlates. The main outcome of this study was policy adoption. Using the Diffusion of Innovation Theory and results from previous literature, we identified several factors that had the potential to affect the rate of Complete Streets policy diffusion: rural/urban status, state obesity rate, state funding for transportation, state obesity prevention funding, percentage of people who walk or bike to work in the state, presence of a state Complete Streets policy, and the number of bordering communities with Complete Streets policy. We used event history analysis as the main analysis method. Data from 49 community-level policies were analyzed, with a "community" defined as a city, a county, or a regional/Metropolitan Planning Organization. Three variables were significant predictors of Complete Streets policy adoption: state obesity rate (odds ratio [OR] = 1.465; confidence interval [CI] = 1.10-1.96) percentage of people who bike or walk to work in the state (OR = 1.726; CI = 1.069-2.79), and presence of a border community with a Complete Streets policy (OR = 3.859; CI = 1.084-13.742). Communities with Complete Streets policies varied in geographic and sociodemographic factors. Information about communities that are more likely to adopt a policy can be a tool for advocates and policy makers interested in this topic. Because adoption does not imply implementation, further research is needed to study

  16. Road and Street Centerlines, StreetLabels-The data set is a text feature consisting of 6329 label points representing street names. It was created to show the names of city and county based streets., Published in 1989, Davis County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Road and Street Centerlines dataset current as of 1989. StreetLabels-The data set is a text feature consisting of 6329 label points representing street names. It was...

  17. Sediment management for reservoir

    International Nuclear Information System (INIS)

    Rahman, A.

    2005-01-01

    All natural lakes and reservoirs whether on rivers, tributaries or off channel storages are doomed to be sited up. Pakistan has two major reservoirs of Tarbela and Managla and shallow lake created by Chashma Barrage. Tarbela and Mangla Lakes are losing their capacities ever since first impounding, Tarbela since 1974 and Mangla since 1967. Tarbela Reservoir receives average annual flow of about 62 MAF and sediment deposits of 0.11 MAF whereas Mangla gets about 23 MAF of average annual flows and is losing its storage at the rate of average 34,000 MAF annually. The loss of storage is a great concern and studies for Tarbela were carried out by TAMS and Wallingford to sustain its capacity whereas no study has been done for Mangla as yet except as part of study for Raised Mangla, which is only desk work. Delta of Tarbala reservoir has advanced to about 6.59 miles (Pivot Point) from power intakes. In case of liquefaction of delta by tremor as low as 0.12g peak ground acceleration the power tunnels I, 2 and 3 will be blocked. Minimum Pool of reservoir is being raised so as to check the advance of delta. Mangla delta will follow the trend of Tarbela. Tarbela has vast amount of data as reservoir is surveyed every year, whereas Mangla Reservoir survey was done at five-year interval, which has now been proposed .to be reduced to three-year interval. In addition suspended sediment sampling of inflow streams is being done by Surface Water Hydrology Project of WAPDA as also some bed load sampling. The problem of Chasma Reservoir has also been highlighted, as it is being indiscriminately being filled up and drawdown several times a year without regard to its reaction to this treatment. The Sediment Management of these reservoirs is essential and the paper discusses pros and cons of various alternatives. (author)

  18. effects of sediment input on aquatic animal communities in New

    African Journals Online (AJOL)

    USER

    the silt determiners the abundance of macroinvertebrates hence the increase in the population in the month of Nov, while Sept(43%) ... result in sediments inputs and deposition in water bodies. (Cuker, 1987). ... reduction in food quality.

  19. Sedimentation patterns in floodplains of the Mekong Delta - Vietnam

    Science.gov (United States)

    Van Manh, Nguyen; Merz, Bruno; Viet Dung, Nguyen; Apel, Heiko

    2013-04-01

    Quantification of floodplain sedimentation during the flood season in the Mekong Delta (MD) plays a very important role in the assessment of flood deposits for a sustainable agro-economic development. Recent studies on floodplain sedimentation in the region are restricted to small pilot sites because of the large extend of the Delta, and the complex channel. This research aims at a quantification of the sediment deposition in floodplains of the whole Mekong Delta, and to access the impacts of the upstream basin development on the sedimentation in the Delta quantitatively. To achieve this, a suspended sediment transport model is developed based on the quasi-2D hydrodynamic model of the whole Mekong Delta developed by Dung et al. (2011). The model is calibrated and validated using observed data derived from several sediment measurement campaigns in channel networks and floodplains. Measured sediment data and hydrodynamic model quantify the spatio-temporal variability of sediment depositions in different spatial units: individual dyke compartments, and the sub-regions Plain of Reeds, Long Xuyen Quadrangle and the area between Tien River and Hau River. It is shown that the distribution of sediment deposition over the delta is highly depended on the flood magnitude, that in turn drives the operation policy of flood control systems in floodplains of the Mekong Delta. Thus, the sedimentation distribution is influenced by the protection level of the dyke systems in place and the distance to the Tien River and Hau River, the main branches of the Mekong in the Delta. This corroborates the main findings derived from data analysis