WorldWideScience

Sample records for bay impact structure

  1. Chesapeake Bay Impact Structure Deep Drilling Project Completes Coring

    Directory of Open Access Journals (Sweden)

    the Scientific Staff of the Chesapeake Bay Impact Structure Deep Drilling Project

    2006-09-01

    Full Text Available The Chesapeake Bay Impact Structure Deep Drilling Project (CBIS Project completed its coring operations during September–December 2005 and April–May 2006. Cores were collected continuously to a total depth of 1766 m. The recovered section consists of 1322 m of impactites beneath 444 m of post-impact continental shelf sediments.The CBIS Project is a joint venture of the International Continental Scientifi c Drilling Program (ICDP and the U.S. Geological Survey (USGS. Project activities began with a planning workshop in September 2003 attended by sixtythree scientists from ten countries. Field operations began with site preparation in July 2005, and coring began in September 2005. Drilling, Observation and Sampling of theEarth’s Continental Crust (DOSECC was the general contractor for the drilling operations throughout 2005.

  2. Coesite in suevites from the Chesapeake Bay impact structure

    Science.gov (United States)

    Jackson, John C.; Horton, J. Wright; Chou, I.-Ming; Belkin, Harvey E.

    2016-05-01

    The occurrence of coesite in suevites from the Chesapeake Bay impact structure is confirmed within a variety of textural domains in situ by Raman spectroscopy for the first time and in mechanically separated grains by X-ray diffraction. Microtextures of coesite identified in situ investigated under transmitted light and by scanning electron microscope reveal coesite as micrometer-sized grains (1-3 μm) within amorphous silica of impact-melt clasts and as submicrometer-sized grains and polycrystalline aggregates within shocked quartz grains. Coesite-bearing quartz grains are present both idiomorphically with original grain margins intact and as highly strained grains that underwent shock-produced plastic deformation. Coesite commonly occurs in plastically deformed quartz grains within domains that appear brown (toasted) in transmitted light and rarely within quartz of spheroidal texture. The coesite likely developed by a mechanism of solid-state transformation from precursor quartz. Raman spectroscopy also showed a series of unidentified peaks associated with shocked quartz grains that likely represent unidentified silica phases, possibly including a moganite-like phase that has not previously been associated with coesite.

  3. First results of geothermal investigations, Chesapeake Bay impact structure, Eyreville core holes

    Czech Academy of Sciences Publication Activity Database

    Heidinger, P.; Wilhelm, H.; Popov, Y.; Šafanda, Jan; Burkhardt, H.; Mayr, S.

    Boulder : The Geological Society of America , 2009 - (Gohn, G.), s. 931-940 ISBN 978-0-8137-2458-4. - (Special paper. 458) R&D Projects: GA MŠk LA08036 Institutional research plan: CEZ:AV0Z30120515 Keywords : Chesapeake Bay * impact structure * deep borehole * temperature log * geothermal model Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  4. Postimpact deposition in the Chesapeake Bay impact structure: Variations in eustasy, compaction, sediment supply, and passive-aggressive tectonism

    Science.gov (United States)

    Kulpecz, A.A.; Miller, K.G.; Browning, J.V.; Edwards, L.E.; Powars, D.S.; McLaughlin, P.P., Jr.; Harris, A.D.; Feigenson, M.D.

    2009-01-01

    The Eyreville and Exmore, Virginia, core holes were drilled in the inner basin and annular trough, respectively, of the Chesapeake Bay impact structure, and they allow us to evaluate sequence deposition in an impact crater. We provide new high-resolution geochronologic (<1 Ma) and sequence-stratigraphic interpretations of the Exmore core, identify 12 definite (and four possible) postimpact depositional sequences, and present comparisons with similar results from Eyreville and other mid- Atlantic core holes. The concurrence of increases in ??18O with Chesapeake Bay impact structure sequence boundaries indicates a primary glacioeustatic control on deposition. However, regional comparisons show the differential preservation of sequences across the mid-Atlantic margin. We explain this distribution by the compaction of impactites, regional sediment-supply changes, and the differential movement of basement structures. Upper Eocene strata are thin or missing updip and around the crater, but they thicken into the inner basin (and offshore to the southeast) due to rapid crater infilling and concurrent impactite compaction. Oligocene sequences are generally thin and highly dissected throughout the mid-Atlantic region due to sediment starvation and tectonism, except in southeastern New Jersey. Regional tectonic uplift of the Norfolk Arch coupled with a southward decrease in sediment supply resulted in: (1) largely absent Lower Miocene sections around the Chesapeake Bay impact structure compared to thick sections in New Jersey and Delaware; (2) thick Middle Miocene sequences across the Delmarva Peninsula that thin south of the Chesapeake Bay impact structure; and (3) upper Middle Miocene sections that pinch out just north of the Chesapeake Bay impact structure. Conversely, the Upper Miocene-Pliocene section is thick across Virginia, but it is poorly represented in New Jersey because of regional variations in relative subsidence. ?? 2009 The Geological Society of America.

  5. Anatomy of the Chesapeake Bay impact structure revealed by seismic imaging, Delmarva Peninsula, Virginia, USA

    Science.gov (United States)

    Catchings, R.D.; Powars, D.S.; Gohn, G.S.; Horton, J.W., Jr.; Goldman, M.R.; Hole, J.A.

    2008-01-01

    A 30-km-long, radial seismic reflection and refraction survey completed across the northern part of the late Eocene Chesapeake Bay impact structure (CBIS) on the Delmarva Peninsula, Virginia, USA, confirms that the CBIS is a complex central-peak crater. We used a tomographic P wave velocity model and low-fold reflection images, constrained by data from two deep boreholes located on the profile, to interpret the structure and composition of the upper 5 km of crust. The seismic images exhibit well-defined structural features, including (with increasing radial distance) a collapsed central uplift, a breccia-filled moat, and a collapsed transient-crater margin (which collectively constitute a ???40-km-wide collapsed transient crater), and a shallowly deformed annular trough. These seismic images are the first to resolve the deep structure of the crater (>1 km) and the boundaries between the central uplift, moat, and annular trough. Several distinct seismic signatures distinguish breccia units from each other and from more coherent crystalline rocks below the central uplift, moat, and annular trough. Within the moat, breccia extends to a minimum depth of 1.5 km or a maximum of 3.5 km, depending upon the interpretation of the deepest layered materials. The images show ???350 to 500 m of postimpact sediments above the impactites. The imaged structure of the CBIS indicates a complex sequence of event during the cratering process that will provide new constraints for numerical modeling. Copyright 2008 by the American Geophysical Union.

  6. Processing of single channel air and water gun data for imaging an impact structure at the Chesapeake Bay

    Science.gov (United States)

    Lee, Myung W.

    1999-01-01

    Processing of 20 seismic profiles acquired in the Chesapeake Bay area aided in analysis of the details of an impact structure and allowed more accurate mapping of the depression caused by a bolide impact. Particular emphasis was placed on enhancement of seismic reflections from the basement. Application of wavelet deconvolution after a second zero-crossing predictive deconvolution improved the resolution of shallow reflections, and application of a match filter enhanced the basement reflections. The use of deconvolution and match filtering with a two-dimensional signal enhancement technique (F-X filtering) significantly improved the interpretability of seismic sections.

  7. Physical property data from the ICDP-USGS Eyreville cores A and B, Chesapeake Bay impact structure, Virginia, USA, acquired using a multisensor core logger

    Science.gov (United States)

    Pierce, H.A.; Murray, J.B.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS) drilled three core holes to a composite depth of 1766 m within the moat of the Chesapeake Bay impact structure. Core recovery rates from the drilling were high (??90%), but problems with core hole collapse limited the geophysical downhole logging to natural-gamma and temperature logs. To supplement the downhole logs, ??5% of the Chesapeake Bay impact structure cores was processed through the USGS GeoTek multisensor core logger (MSCL) located in Menlo Park, California. The measured physical properties included core thickness (cm), density (g cm-3), P-wave velocity (m s-1), P-wave amplitude (%), magnetic susceptibility (cgs), and resistivity (ohm-m). Fractional porosity was a secondary calculated property. The MSCL data-sampling interval for all core sections was 1 cm longitudinally. Photos of each MSCL sampled core section were imbedded with the physical property data for direct comparison. These data have been used in seismic, geologic, thermal history, magnetic, and gravity models of the Chesapeake Bay impact structure. Each physical property curve has a unique signature when viewed over the full depth of the Chesapeake Bay impact structure core holes. Variations in the measured properties reflect differences in pre-impact target-rock lithologies and spatial variations in impact-related deformation during late-stage crater collapse and ocean resurge. ?? 2009 The Geological Society of America.

  8. An ecological model of the artificial ecosystem (northern Hangzhou Bay, China): analysis of ecosystem structure and fishing impacts

    Science.gov (United States)

    Chen, Zuozhi; Xu, Shannan; He, Peimin

    2011-06-01

    The artificial ecosystem is a large-scale enclosure in northern Hangzhou Bay, China. Using the Ecopath with Ecosim software, a trophic structure model is constructed for 2006-2007 to characterize the food web structure, functioning, and describing the ecosystem impacts of fishing. Input information for the model were gathered from published and unpublished reports and from our own estimates during the period 2006-2007. Pedigree work and simple sensitivity analysis were carried out to evaluate the quality and the uncertainty of the model. Results show that the food web in the enclosed sea area was dominated by a detritus pathway. The trophic levels of the groups varied from 1.00 for primary producers and detritus to 3.90 for piscivorous fish in the artificial system. Using network analysis, the system network was mapped into a linear food chain, and five discrete trophic levels were found with a mean transfer efficiency of 9.8% from detritus, 9.4% from primary producer within the ecosystem. The geometric mean of the trophic transfer efficiencies was 9.5%. Detritus contributed 57% of the total energy flux, and the other 43% came from primary producers. The ecosystem maturity indices-TPP/TR (total primary production/total respiration), FCI (Finn cycling index), A (ascendancy) and TB/TDET were 2.672, 25%, 31.5%, and 0.013, respectively, showing that the artificial system is at developmental stage according to Odum's theory of ecosystem development. The `Keystoneness' result indicates that herbivorous zooplankton was identified as keystone species in this system. Furthermore, a simple dynamical simulation was preformed for varying fishing mortality over 10 years. The biomass of most fish groups has a small increase when the fishing mortality at current level. Increasing fishing mortality by twofold resulted in a marked decrease in biomass of piscivorous fish accompanied by an increase in that of other fish groups, notable zooplanktivorous fish. Generally, this study

  9. Impact of predation by Ostracion immaculatus (Pisces: Ostraciidae) on the macrofouling community structure in Kanayama Bay, Kii Peninsula (Japan)

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Harada, E.

    using predator inclusion as well as exclusion treatment confirmed that predation by this fish had significant impact on the structure of fouling community. The importance of predation was manifested mainly through the influence of fish on ascidians...

  10. Geochemical characteristics of basement target rocks, suevitic glasses from the Eyreville B drill core, Chesapeake Bay impact structure, and three bediasites

    Czech Academy of Sciences Publication Activity Database

    Skála, Roman; Langenhorst, F.; Deutsch, A.

    Boulder: Geological Society of America, 2009, s. 435-445. (Special papers of the Geological Society of America). ISBN 978-0-8137-2458-4 Institutional research plan: CEZ:AV0Z30130516 Keywords : Chesapeake Bay impact crater * Eyreville B core hole * impact glasses * bediasites * tektites * geochemistry Subject RIV: DD - Geochemistry

  11. Social and environmental impacts of the James Bay hydroelectric project

    International Nuclear Information System (INIS)

    The book, which is an analysis and not an advocacy, examines the anatomy of the controversy that has swirled around the James Bay project - the La Grande and Great Whale projects combined - from the 1970s to the 1990s, and seeks, in the process, to determine whether there are lessons that can be learned from such an analysis that are applicable to other cases as well as to James Bay itself. The contributors are interested, at one and the same time, in finding ways to integrate the knowledge of natural scientists and social scientists to deepen the understanding of human/environment relations and to link science and policy to encourage a productive dialogue between practitioners and scholars in this increasingly important area of inquiry. The contributor's papers include the following: introduction to the issues; hydroelectric power development at James Bay: establishing a frame of reference; James Bay: environmental considerations for building large hydroelectric dams and reservoirs in Quebec; elevated mercury in fish as a result of the James Bay hydroelectric power development: perception and reality; the Cree people of James Bay: assessing the social impacts of hydroelectric dams and reservoirs; culture, social change, and Cree opposition to the James Bay hydroelectric development; and the impact of James Bay hydroelectric development on the art and craft of the James Bay Cree. The authors of the volume have attempted to stand back and examine just a few of these issues from the perspective of a variety of disciplines, and their purpose is to inform and stimulate thoughtful consideration by providing an overall perspective that might might serve to broaden the context in which specific issues can be debated. refs., 3 tabs., 5 figs

  12. Meteorological impact of realistic Terra Nova Bay polynyas.

    Science.gov (United States)

    Morelli, Sandra

    2010-05-01

    The energy exchange between the ocean and the atmosphere in the Antarctic marginal sea ice zone is influenced by the extent of sea-ice cover. In areas of open water, a direct contact is established and intense energy exchanges occur, due to the large difference of temperature between the water and the air above it. This implies that the polynyas are areas where the ocean exchanges energy with the atmosphere and as a result they have an effect on the polar meteorology/climate. The work presented here concerns real polynya events in the region of Terra Nova Bay (TNB), Antarctica, where a recurring coastal polynya occurs nearby the Italian Antarctic Base. The aim is the study of the impact of polynyas on the atmosphere by three-dimensional numerical simulations. The ETA model (Mesinger et al., 2006) was used and ECMWF and NCEP data provided the initial and boundary conditions. The model had already been successfully used in the Antarctic area (Casini and Morelli, 2007) A polynya of realistic size (as observed by satellite image) was included in the initial conditions for the simulations and a study of the air circulation during the events is found in Morelli et al. (2007), Morelli and Casini (2008), Morelli et al. (2009). The Eta Model reproduced the evolution of upper and mod-level conditions in good agreement with AVHRR observations (Morelli, 2008, Morelli and Parmiggiani, 2009). Also, the simulated 10 m wind was well correlated with the observed extension of the polynya. In order to isolate the effect of the presence of the open water area on the structure of the atmospheric boundary layer and on the atmospheric circulation, further simulations were performed without the presence of the polynya, i.e. with its extent covered with sea ice. The numerical simulations show that the polynyas act to increase the speed of the air above them and generate strong heat fluxes that warm the air. The effects are found over and downwind the sea ice free area. Results from the Eta

  13. San Francisco Bay Sand Mining Resource Evaluation and Impact Analysis

    Science.gov (United States)

    Fenical, S.; Tirindelli, M.; Sicular, D.; Gragg, J.; Huitt, C.

    2012-12-01

    This paper presents results of the evaluation of potential future sand resources within certain Central San Francisco Bay (Central Bay) sand mining lease areas, as well as the potential impacts of further mining these areas for a ten-year period. The study consisted of morphological analysis using field measurements and hydrodynamic modeling, and covered a wide spectrum of physical processes including tidal and river circulation, salinity, sediment transport, and morphology. The study was conducted within the framework of an Environmental Impact Report (EIR) prepared by the California State Lands Commission (CSLC) as part of the discretionary approval process for issuing new mining leases. The results of the morphological analysis indicate a measurable depletion of sand resources in the Central Bay lease areas during the period 1997-2008, and that for the purposes of the proposed ten-year mining lease renewal, sand mining resources in Central Bay are largely limited to material already in place. The morphological analysis results also indicate that the proposed additional ten years of sand mining in the Central Bay lease areas are not likely to cause a significant impact on sediment transport and budgets in areas outside the vicinity of the lease areas, such as the San Francisco Bar, Ocean Beach, etc. Numerical modeling results, including particle tracking exercises, do indicate a net seaward transport of sand, and that a linkage exists between the mining areas and offshore areas (San Francisco Bar, Ocean Beach, etc). However, the modeling results demonstrate that the linkage is weak, and that any measurable changes in hydrodynamics, salinity and sediment transport/morphology caused by the mining activities are likely to be confined to the vicinity of the mining areas.

  14. Using a food-web model to assess the trophic structure and energy flows in Daya Bay, China

    Science.gov (United States)

    Chen, Zuozhi; Xu, Shannan; Qiu, Yongsong

    2015-12-01

    Daya Bay, is one of the largest and most important semi-closed bays along the southern coast of China. Due to the favorable geomorphological and climatic conditions, this bay has become an important conservation zone of aquatic germplasm resources in South China Sea. To characterize the trophic structure, ecosystem properties and keystone species, a food-web model for Daya Bay has been developed by the means of a mass-balance approach using the Ecopath with Ecosim software. The mean trophic transfer efficiency for the entire ecosystem as a whole is 10.9% while the trophic level II is 5.1%. The primary- and secondary-producers, including phytoplankton, zooplankton and micro-zoobenthos demonstrated the important overall impacts on the rest of the groups based on mixed trophic impact (MIT) analysis and are classified as the keystone groups. The analysis of ecosystem attributes indicated that ecosystem of Daya Bay can be categorized as an immature one and/or is in the degraded stage. A comparison of this model with other coastal ecosystems, including Kuosheng Bay, Tongoy Bay, Beibu Gulf and Cadiz Gulf, underpinned that the ecosystem of Daye Bay is an obviously stressed system and is more vulnerable to the external disturbance. In general, our study indicates that a holistic approach is needed to minimize the impacts of anthropogenic activities to ensure the sustainability of the ecosystem in the future.

  15. 78 FR 25266 - An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska

    Science.gov (United States)

    2013-04-30

    ... assessment to determine the significance of Bristol Bay's ecological resources and the potential impacts of... and mineral resources of the Bristol Bay watershed, increase understanding of the potential impacts of... draft was released for public comment on May 18, 2012 (77 FR 31353, May 25, 2012). Peer review...

  16. Impact of Ganges–Brahmaputra interannual discharge variations on Bay of Bengal salinity and temperature during 1992–1999 period

    Indian Academy of Sciences (India)

    Fabien Durand; Fabrice Papa; Atiqur Rahman; Sujit Kumar Bala

    2011-10-01

    This study investigates the impact of monthly Ganges–Brahmaputra river discharge variations on Bay of Bengal salinity and temperature during the period 1992–1999. The Ganges–Brahmaputra river discharge is characterized by a well-defined seasonal cycle with strong interannual variations. The highest/lowest yearly peak discharge occurs in summer 1998/summer 1992, with 1998 value amounting to twice that of 1992. This river discharge is then used to force an ocean general circulation model. Our main result is that the impact of these rivers on the variability of Bay of Bengal sea surface salinity is strong in the northern part, with excess run-off forcing fresh anomalies, and vice versa. Most of the years, the influence of the interannual variability of river discharge on the Bay salinity does not extend south of ∼10° N. This stands in contrast with the available observations and is probably linked to the relatively coarse resolution of our model. However, the extreme discharge anomaly of 1998 is exported through the southern boundary of the Bay and penetrates the south-eastern Arabian Sea a few months after the discharge peak. In response to the discharge anomalies, the model simulates significant mixed-layer temperature anomalies in the northern Bay of Bengal. This has the potential to influence the climate of the area. From our conclusions, it appears necessary to use a numerical model with higher resolution (both on the horizontal and vertical) to quantitatively investigate the upper Bay of Bengal salinity structure.

  17. Use of Geographic Information Systems to examine cumulative impacts of development on Mobile Bay, AL and Galveston Bay, TX

    International Nuclear Information System (INIS)

    Databases from Mobile Bay, Alabama and Galveston Bay, Texas were compiled using ARC/INFO Geographic Information Systems (GIS) to examine the cumulative impacts from urbanization and industrialization on these two Gulf of Mexico estuaries. The databases included information on wetland habitats, pollution sources, metal contamination, bird-nesting sites, and oyster reefs, among others. A series of maps were used to represent the impacts within and between each ecosystem. These two estuaries share many similarities in the types of developmental pressures that each experience. However, difference in the magnitude of industrial activity, pollution loading, and urban growth coupled with distinct hydrodynamic and geochemical differences in sediment mineralogy, freshwater inflows and salinity regimens results in differing responses. With growing human population and extensive oil and gas development, the demands on Galveston Bay are quite different than those placed on Mobile Bay which has lower growth and less extensive oil and gas infrastructure. Mobile Bay tends to retain whatever contamination enters into the system because of the high levels of clay and organic carbon found in its sediment. Some of these chemicals bioaccumulate, posing an extra risk to natural resources. Geographic Information Systems provide natural resource managers with the technology to manage complex databases. The analytical and mapping capabilities of GIS can be used to consider cumulative effects in a regional context and to develop plans to protect ecologically sensitive areas

  18. Postimpact heat conduction and compaction-driven fluid flow in the Chesapeake Bay impact structure based on downhole vitrinite reflectance data, ICDP-USGS Eyreville deep core holes and Cape Charles test holes

    Science.gov (United States)

    Malinconico, M.L.; Sanford, W.E.; Wright, Horton W.J.J., Jr.

    2009-01-01

    Vitrinite reflectance data from the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville deep cores in the centralcrater moat of the Chesapeake Bay impact structure and the Cape Charles test holes on the central uplift show patterns of postimpact maximum-temperature distribution that result from a combination of conductive and advective heat flow. Within the crater-fill sediment-clast breccia sequence at Eyreville, an isoreflectance (-0.44% Ro) section (525-1096 m depth) is higher than modeled background coastal-plain maturity and shows a pattern typical of advective fluid flow. Below an intervening granite slab, a short interval of sediment-clast breccia (1371-1397 m) shows a sharp increase in reflectance (0.47%-0.91% Ro) caused by conductive heat from the underlying suevite (1397-1474 m). Refl ectance data in the uppermost suevite range from 1.2% to 2.1% Ro. However, heat conduction alone is not sufficient to affect the temperature of sediments more than 100 m above the suevite. Thermal modeling of the Eyreville suevite as a 390 ??C cooling sill-like hot rock layer supplemented by compaction- driven vertical fluid flow (0.046 m/a) of cooling suevitic fluids and deeper basement brines (120 ??C) upward through the sediment breccias closely reproduces the measured reflectance data. This scenario would also replace any marine water trapped in the crater fill with more saline brine, similar to that currently in the crater, and it would produce temperatures sufficient to kill microbes in sediment breccias within 450 m above the synimsuevite. A similar downhole maturity pattern is present in the sediment-clast breccia over the central uplift. High-reflectance (5%-9%) black shale and siltstone clasts in the suevite and sediment-clast breccia record a pre-impact (Paleozoic?) metamorphic event. Previously published maturity data in the annular trough indicate no thermal effect there from impact-related processes. ?? 2009 The

  19. Structuring of bacterioplankton diversity in a large tropical bay.

    Directory of Open Access Journals (Sweden)

    Gustavo B Gregoracci

    Full Text Available Structuring of bacterioplanktonic populations and factors that determine the structuring of specific niche partitions have been demonstrated only for a limited number of colder water environments. In order to better understand the physical chemical and biological parameters that may influence bacterioplankton diversity and abundance, we examined their productivity, abundance and diversity in the second largest Brazilian tropical bay (Guanabara Bay, GB, as well as seawater physical chemical and biological parameters of GB. The inner bay location with higher nutrient input favored higher microbial (including vibrio growth. Metagenomic analysis revealed a predominance of Gammaproteobacteria in this location, while GB locations with lower nutrient concentration favored Alphaproteobacteria and Flavobacteria. According to the subsystems (SEED functional analysis, GB has a distinctive metabolic signature, comprising a higher number of sequences in the metabolism of phosphorus and aromatic compounds and a lower number of sequences in the photosynthesis subsystem. The apparent phosphorus limitation appears to influence the GB metagenomic signature of the three locations. Phosphorus is also one of the main factors determining changes in the abundance of planktonic vibrios, suggesting that nutrient limitation can be observed at community (metagenomic and population levels (total prokaryote and vibrio counts.

  20. When it happens again: impact of future San Francisco Bay area earthquakes

    Science.gov (United States)

    Zoback, M.; Boatwright, J.; Kornfield, L.; Scawthorn, C.; Rojahn, C.

    2005-12-01

    San Francisco Bay area earthquakes, like major floods and hurricanes, have the potential for massive damage to dense urban population centers concentrated in vulnerable zones-along active faults, in coastal regions, and along major river arteries. The recent destruction of Hurricane Katrina does have precedent in the destruction following the 1906 "San Francisco" earthquake and fire in which more than 3000 people were killed and 225,000 were left homeless in San Francisco alone, a city of 400,000 at the time. Analysis of a comprehensive set of damage reports from the magnitude (M) 7.9 1906 earthquake indicates a region of ~ 18,000 km2 was subjected to shaking of Modified Mercalli Intensity of VIII or more - motions capable of damaging even modern, well-built structures; more than 60,000 km2 was subjected to shaking of Intensity VII or greater - the threshold for damage to masonry and poorly designed structures. By comparison, Katrina's hurricane force winds and intense rainfall impacted an area of ~100,000 km2 on the Gulf Coast. Thus, the anticipated effects of a future major Bay Area quake to lives, property, and infrastructure are comparable in scale to Katrina. Secondary hazards (levee failure and flooding in the case of Katrina and fire following the 1906 earthquake) greatly compounded the devastation in both disasters. A recent USGS-led study concluded there is a 62% chance of one or more damaging (M6.7 or greater) earthquakes striking the greater San Francisco Bay area over the next 30 years. The USGS prepared HAZUS loss estimates for the 10 most likely forecast earthquakes which range in size from a M6.7 event on a blind thrust to the largest anticipated event, a M7.9 repeat of the 1906 earthquake. The largest economic loss is expected for a repeat of the 1906 quake. Losses in the Bay region for this event are nearly double those predicted for a M6.9 rupture of the entire Hayward Fault in the East Bay. However, because of high density of population along the

  1. 77 FR 31353 - An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, AK

    Science.gov (United States)

    2012-05-25

    ... significance of Bristol Bay's ecological resources and evaluate the potential impacts of large-scale mining on... ecological resources and evaluate the potential impacts of large-scale mining on these resources. The EPA... draft document addresses potential impacts to water quality and the salmon fishery that may result...

  2. 76 FR 59423 - Drakes Bay Oyster Company Special-Use Permit, Draft Environmental Impact Statement, Point Reyes...

    Science.gov (United States)

    2011-09-26

    ... whether a new SUP should be issued to Drakes Bay Oyster Company for 10 years. ] Project Objectives Manage... National Park Service Drakes Bay Oyster Company Special-Use Permit, Draft Environmental Impact Statement... statement to consider the Drakes Bay Oyster Company Special-use permit in Drakes Estero, Point...

  3. Structures of the Bohai Petroliferous Area, Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper, for the first time, deals with a more systematic study of the structures in the Bohai petroliferous area that covers nearly one third of the Bohai Bay basin. The study mainly involves the effects of pre-existing basement faults on the basin formation, the characteristics of basin geometry and kinetics, the modelling of the tectonic-thermal history, the polycyclicity and heterogeneity in the structural evolution and the natural seismic tomographic images of the crust and upper mantle. The authors analyze the features of the dynamic evolution of the basin in the paper and point out that the basin in the Bohai petroliferous area is an extensional pull-apart basin.

  4. 78 FR 34093 - An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska

    Science.gov (United States)

    2013-06-06

    ... potential impacts of large-scale mining on these resources. DATES: The public comment period began on April... and mineral resources of the Bristol Bay watershed, to increase understanding of the potential impacts... previous draft was released for public comment on May 18, 2012 (77 FR 31353, May 25, 2012). Peer...

  5. Bay-scale population structure in coastal Atlantic cod in Labrador and Newfoundland, Canada

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Wroblewski, J.S.; Taggart, C.T.; Smedbol, R.K.; Cook, D.; Goddard, S.V.

    2000-01-01

    Polymorphisms at five microsatellite DNA loci provide evidence that Atlantic cod Gadus morhua inhabiting Gilbert Bay, Labrador are genetically distinguishable from offshore cod on the north- east Newfoundland shelf and from inshore cod in Trinity Bay, Newfoundland. Antifreeze activity in the blood...... population structure suggest that important barriers to gene flow exist among five components that include two inshore (Gilbert and Trinity Bay) and three offshore cod aggregations on the north-east Newfoundland Shelf and the Grand Bank. D-A and D-SW estimates of genetic distance that involve Gilbert Bay cod...

  6. Investigation of MMOD Impact on STS-115 Shuttle Payload Bay Door Radiator

    Science.gov (United States)

    Hyde, J.; Christiansen, E.; Lear, D.; Kerr, J.; Lyons, F.; Yasensky, J.

    2007-01-01

    The Orbiter radiator system consists of eight individual 4.6 m x 3.2 m panels located with four on each payload bay door. Forward panels #1 and #2 are 2.3 cm thick while the aft panels #3 and #4 have a smaller overall thickness of 1.3 cm. The honeycomb radiator panels consist of 0.028 cm thick Aluminum 2024-T81 facesheets and Al5056-H39 cores. The face-sheets are topped with 0.005 in. (0.127 mm) silver-Teflon tape. The radiators are located on the inside of the shuttle payload bay doors, which are closed during ascent and reentry, limiting damage to the on-orbit portion of the mission. Post-flight inspections at the Kennedy Space Center (KSC) following the STS-115 mission revealed a large micrometeoroid/orbital debris (MMOD) impact near the hinge line on the #4 starboard payload bay door radiator panel. The features of this impact make it the largest ever recorded on an orbiter payload bay door radiator. The general location of the damage site and the adjacent radiator panels can be seen in Figure 2. Initial measurements of the defect indicated that the hole in the facesheet was 0.108 in. (2.74 mm) in diameter. Figure 3 shows an image of the front side damage. Subsequent observations revealed exit damage on the rear facesheet. Impact damage features on the rear facesheet included a 0.03 in. diameter hole (0.76 mm), a approx.0.05 in. tall bulge (approx.1.3 mm), and a larger approx.0.2 in. tall bulge (approx.5.1 mm) that exhibited a crack over 0.27 in. (6.8 mm) long. A large approx.1 in. (25 mm) diameter region of the honeycomb core was also damaged. Refer to Figure 4 for an image of the backside damage to the panel. No damage was found on thermal blankets or payload bay door structure under the radiator panel. Figure 5 shows the front facesheet with the thermal tape removed. Ultrasound examination indicated a maximum facesheet debond extent of approximately 1 in. (25 mm) from the entry hole. X-ray examinations revealed damage to an estimated 31 honeycomb cells with

  7. A discussion on typhoon occurred in the Haikou Bay and impact mechanism on seawater quality

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Water quality parameters such as pH, DO, COD, PO4 - P, SiO3 - Si, NO2 - N, NO3 -N in the Haikou Bay were monitored respectively before and after Typhoon 9618 occurring on Sep. 18,1996. Based on the statistics of typhoon in the Haikou Bay and numerical calculation of stormy current,the mechanism of water quality variation caused by typhoon is discussed. The typhoon impact on the Haikou Bay usually appears between July and November, most usually between August and October.The monitoring results before a typhoon were different from that. The stormy wave and windstorm cur rent stir up the sediment in near-shore bottom and make the bottom water mix with the surface water strongly, specially windstorm current with strong velocity at the head of the bay stirs up higher pollu tants sediment near sea area of sewage outfall, and heavy rain with typhoon carries the pollutants from land through the Nandu River to the Haikou Bay, so the contents of COD, PO4 - P, NO2 - N, NO3 -N, SiO3 after a typhoon are higher than those before. Windstorm current is violent, which makes offshore high DO water exchange more frequently with inner bay water and oxygen in the air dissolves in sea water faster, so DO content after typhoon is higher than that before typhoon. This strong action of water exchange also causes lower pH change before and after the typhoon.

  8. 76 FR 7807 - Thorne Bay Ranger District; Alaska; Big Thorne Project Environmental Impact Statement

    Science.gov (United States)

    2011-02-11

    ... transition to a sustainable forest industry based on young-growth management. Forest restoration and... the Tongass Land Management Plan. While the Forest Service is proposing timber harvest in this project... Forest Service Thorne Bay Ranger District; Alaska; Big Thorne Project Environmental Impact...

  9. Indicators and impact analysis of sediment from the Changjiang Estuary and East China Sea to the Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; FAN Wei; YUN Caixing

    2004-01-01

    Based on the historical evolution of the Hangzhou Bay, by making use of the conclusions made by the previous research workers and the integration of concrete data, five distinct impact indicators of the sediment from the Changjiang Estuary and the East China Sea to the Hangzhou Bay are summarized. Numerical calculation and analysis indicate that the scouring and deposition of seabed in the Hangzhou Bay are subject to the direct impact of the evolution of the Changjiang Estuary, and the growth and decline and the direction of the sandy bar at Nanhuizui give traces to the sediment transport between the Changjiang Estuary and the Hangzhou Bay. The transport of sediment from the Changjiang Estuary to the Hangzhou Bay occurs mainly in winter and spring seasons and the increase of the Changjiang River runoff and the decrease of sediment charge have caused scouring in the northern coast of the Hangzhou Bay and the seabed erosion along the frontal margin of the Changjiang River Delta.

  10. Restoration of Lost Lake, recovery of an impacted Carolina Bay

    International Nuclear Information System (INIS)

    Lost Lake is one of approximately 200 Carolina bays found on the Savannah River Site (SRS). Until 1984 Lost Lake was contaminated by heavy metals and solvents overflowing from a nearby settling basin. Up to 12 inches of surface soil and all vegetation was removed from the bay as part of a RCRA removal action. A plan for restoration was initiated in 1989 and implemented in 1990 and 1991. Extensive planning led to defined objectives, strategies, treatments, and monitoring programs allowing successful restoration of Lost Lake. The primary goal of the project was to restore the wetland ecosystem after a hazardous waste clean up operation. An additional goal was to study the progress of the project and the success of the restoration activity. Several strategy considerations were necessary in the restoration plan. The removal of existing organic soils had to have compensation, a treatment scheme for planting and the extent of manipulation of the substrate had to be considered, monitoring decisions had to be made, and the decision whether or not to actively control the hydrology of the restored system

  11. Macrofouling community structure in Kanayama Bay, Kii Peninsula (Japan)

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Harada, E.

    of fouling organisms were monitored at monthly intervals. Fortnightly variations in hydrographic parameters were also noted simultaneously. The fouling community at this bay was a complex assemblage of bryozoans, ascidians, polychaetes and barnacles...

  12. The evaluation of fish farming impact by nutrient content and chlorophyll A in Mala Lamljana bay

    Directory of Open Access Journals (Sweden)

    Jelic-Mrcelic Gorana

    2013-01-01

    Full Text Available This paper offers a brief review of the impacts of fish farming on the nutrient content and chlorophyll a in Mala Lamljana Bay, Croatia. Local loading of nitrogen and phosphorous compounds in fish farms can be very significant and can represent the largest source of N and P in a given area. Low N and P concentrations, low chlorophyll a concentration and a great variety of phytoplankton species were found in the bay, despite the high nutrient loading during the long history of farming in the bay. The phytoplankton community consisted mostly of diatoms and partly of dinoflagellates. Skeletonema costatum and Chaetoceros compressus were the dominant species (90% in summer chlorophyll, which is typical for Middle Adriatic oligotrophic coastal waters. Nevertheless, further studies are required to determine changes in water column factors and planktonic communities in this area.

  13. The impact of physical processes on pollutant transport in Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    LI Ning; MAO Zhihua; ZHANG Qinghe

    2009-01-01

    A Lagrangian tracer model is set up for Hangzhou Bay based on Coupled Hydrodynamical Ecological model for Regional Shelf Sea (COHERENS). The study area is divided into eight subdomains to identify the dominant physical processes, and the studied periods are March (the dry season) and July (the wet season). The model performance has been first verified by sea-surface elevation and tidal current observations at several stations. Eight tracer experiments are designed and Lagrangian particle tracking is simulated to examine the impact of physical processes (tide, wind and river runoff) on the transport of passive tracer released within the surface layer. Numerical simulations and analysis indicate that: (1) wind does not change the tracer distribution after 30 days except for those released from the south area of then bay during the wet season; (2) the tide and the Qiantang River runoff are important for particle transport in the head area of the bay; (3) the Changjiang River runoff affects the tracer transport at the mouth of the bay, and its impact is smaller in the dry season than in the wet season.

  14. Evaluating the Impact of Land Use Change on Submerged Aquatic Vegetation Stressors in Mobile Bay

    Science.gov (United States)

    Al-Hamdan, Mohammad; Estes, Maurice G., Jr.; Quattrochi, Dale; Thom, Ronald; Woodruff, Dana; Judd, Chaeli; Ellis, Jean; Watson, Brian; Rodriquez, Hugo; Johnson, Hoyt

    2009-01-01

    Alabama coastal systems have been subjected to increasing pressure from a variety of activities including urban and rural development, shoreline modifications, industrial activities, and dredging of shipping and navigation channels. The impacts on coastal ecosystems are often observed through the use of indicator species. One such indicator species for aquatic ecosystem health is submerged aquatic vegetation (SAV). Watershed and hydrodynamic modeling has been performed to evaluate the impact of land use change in Mobile and Baldwin counties on SAV stressors and controlling factors (temperature, salinity, and sediment) in Mobile Bay. Watershed modeling using the Loading Simulation Package in C++ (LSPC) was performed for all watersheds contiguous to Mobile Bay for land use scenarios in 1948, 1992, 2001, and 2030. Landsat-derived National Land Cover Data (NLCD) were used in the 1992 and 2001 simulations after having been reclassified to a common classification scheme. The Prescott Spatial Growth Model was used to project the 2030 land use scenario based on current trends. The LSPC model simulations provided output on changes in flow, temperature, and sediment for 22 discharge points into the Bay. Theses results were inputted in the Environmental Fluid Dynamics Computer Code (EFDC) hydrodynamic model to generate data on changes in temperature, salinity, and sediment on a grid with four vertical profiles throughout Mobile Bay. The changes in the aquatic ecosystem were used to perform an ecological analysis to evaluate the impact on SAV habitat suitability. This is the key product benefiting the Mobile Bay coastal environmental managers that integrates the influences of temperature, salinity, and sediment due to land use driven flow changes with the restoration potential of SAVs.

  15. Grazing impact of microzooplankton on phytoplankton in the Xiamen Bay using pigment-specific dilution technique

    Institute of Scientific and Technical Information of China (English)

    HUANG Bangqin; LIU Yuan; XIANG Weiguo; TIAN Haojie; LIU Hongbin; CAO Zhenrui; HONG Huasheng

    2008-01-01

    Phytoplankton group-specific growth and microzooplankton grazing were determined seasonally using the dilution technique with high-performance liquid chromatography (HPLC) in the Xiamen Bay, a subtropical bay in southeast China, between May 2003 and February 2004. The results showed that growth rates of phytoplankton ranged from 0.71 to 2.2 d -1 with the highest value occurred in the inner bay in May. Microzooplankton grazing rates ranged from 0.5 to 3.1 d-1 with the highest value occurred in the inner bay in August. Microzooplankton grazing impact ranged from 39% to 95% on total phytoplankton Chl a biomass, and 65% to 181% on primary production. The growth and grazing rates of each phytoplankton group varied, the highest growth rate (up to 3.3 d -1 ) was recorded for diatoms in August, while the maximum grazing rate ( up to 2.1 d -1 ) was recorded for chlorophytes in February in the inner bay. Among main phytoplankton groups, grazing pressure of microzooplankton ranged from 10% to 83% on Chl a biomass, and from 14% to 151% on primary production. The highest grazing pressure on biomass was observed for cryptophytes (83%) in August, while the maximum grazing pressure on primary production was observed for cyanobacteria (up to 151% ) in December in the inner bay. Net growth rates of larger phytoplanktons (diatoms and dinoflagellates) were higher than those of smaller groups (prasinophytes, chlorophytes and cyanobacteria). Relative preference index showed that microzooplankton grazed preferentially on prasinophytes and avoided to harvest diatoms in cold seasons ( December and February).

  16. Impact of the California sea lion (Zalophus californianus) on salmon fisheries in Monterey Bay, California

    OpenAIRE

    Weise, Michael J; Harvey, James T.

    2005-01-01

    To assess the impact of California sea lions (Zalophus californianus) on salmon fisheries in the Monterey Bay region of California, the percentages of hooked fish taken by sea lions in commercial and recreational salmon fisheries were estimated from 1997 to 1999. Onboard surveys of sea lion interactions with the commercial and recreational f isheries and dockside interviews with fishermen after their return to port were conducted in the ports of Santa Cruz, Moss Landing, and Monterey. Appr...

  17. Potential Impacts and Management Implications of Climate Change on Tampa Bay Estuary Critical Coastal Habitats

    Science.gov (United States)

    Sherwood, Edward T.; Greening, Holly S.

    2014-02-01

    The Tampa Bay estuary is a unique and valued ecosystem that currently thrives between subtropical and temperate climates along Florida's west-central coast. The watershed is considered urbanized (42 % lands developed); however, a suite of critical coastal habitats still persists. Current management efforts are focused toward restoring the historic balance of these habitat types to a benchmark 1950s period. We have modeled the anticipated changes to a suite of habitats within the Tampa Bay estuary using the sea level affecting marshes model under various sea level rise (SLR) scenarios. Modeled changes to the distribution and coverage of mangrove habitats within the estuary are expected to dominate the overall proportions of future critical coastal habitats. Modeled losses in salt marsh, salt barren, and coastal freshwater wetlands by 2100 will significantly affect the progress achieved in "Restoring the Balance" of these habitat types over recent periods. Future land management and acquisition priorities within the Tampa Bay estuary should consider the impending effects of both continued urbanization within the watershed and climate change. This requires the recognition that: (1) the Tampa Bay estuary is trending towards a mangrove-dominated system; (2) the current management paradigm of "Restoring the Balance" may no longer provide realistic, attainable goals; (3) restoration that creates habitat mosaics will prove more resilient in the future; and (4) establishing subtidal and upslope "refugia" may be a future strategy in this urbanized estuary to allow sensitive habitat types (e.g., seagrass and salt barren) to persist under anticipated climate change and SLR impacts.

  18. Population structure and maturity stages of Fritillaria borealis (Appendicularia, Tunicata: seasonal cycle in Ushuaia Bay (Beagle Channel

    Directory of Open Access Journals (Sweden)

    María Laura Presta

    2015-09-01

    Full Text Available AbstractFritillaria borealis is a cosmopolitan species, very frequent in sub-antarctic and antarctic waters. The objective of this paper was to analyze its size structure and maturity stages at two sites in Ushuaia Bay: a coastal site exposed to anthropogenic pressure (E1 and a reference site (E2 located in the external zone of the bay. Zooplankton was collected during the 2012 seasonal cycle. The sampling method involved the use of a 67 µm-mesh net. Appendicularians were classified in four maturity stages: I undifferentiated gonads, II testis and ovary differentiated, III expanded testis, IV discharged testis, expanded ovary. Our results showed that the highest densities of F. borealisoccurred in spring and summer at both sites; coinciding with high values of chlorophyll-a. The percentage of juveniles (I and II exhibited a spatial and temporal pattern similar to that observed for chlorophyll-a values. During spring-summer, juveniles and mature specimens (III and IV showed a greater gonadal development than those individuals found in autumn-winter. In conclusion, the mismatching in the population structure and the pattern of densities of F. borealis between coastal and external zones would suggest the existence of two sub-populations susceptible to the influence of the anthropogenic impact in the bay.

  19. Structured Additive Regression Models: An R Interface to BayesX

    Directory of Open Access Journals (Sweden)

    Nikolaus Umlauf

    2015-02-01

    Full Text Available Structured additive regression (STAR models provide a flexible framework for model- ing possible nonlinear effects of covariates: They contain the well established frameworks of generalized linear models and generalized additive models as special cases but also allow a wider class of effects, e.g., for geographical or spatio-temporal data, allowing for specification of complex and realistic models. BayesX is standalone software package providing software for fitting general class of STAR models. Based on a comprehensive open-source regression toolbox written in C++, BayesX uses Bayesian inference for estimating STAR models based on Markov chain Monte Carlo simulation techniques, a mixed model representation of STAR models, or stepwise regression techniques combining penalized least squares estimation with model selection. BayesX not only covers models for responses from univariate exponential families, but also models from less-standard regression situations such as models for multi-categorical responses with either ordered or unordered categories, continuous time survival data, or continuous time multi-state models. This paper presents a new fully interactive R interface to BayesX: the R package R2BayesX. With the new package, STAR models can be conveniently specified using Rs formula language (with some extended terms, fitted using the BayesX binary, represented in R with objects of suitable classes, and finally printed/summarized/plotted. This makes BayesX much more accessible to users familiar with R and adds extensive graphics capabilities for visualizing fitted STAR models. Furthermore, R2BayesX complements the already impressive capabilities for semiparametric regression in R by a comprehensive toolbox comprising in particular more complex response types and alternative inferential procedures such as simulation-based Bayesian inference.

  20. Impact of extreme metal contamination at the supra-individual level in a contaminated bay ecosystem.

    Science.gov (United States)

    Wu, Bin; Li, Xuegang; Song, Jinming; Hu, Limin; Shi, Xuefa

    2016-07-01

    Anthropogenic stressors impact the global environment and adversely affect the health of organisms and humans. This study was designed as an attempt to evaluate the ecological consequences of severe metal contamination at the supra-individual level based on a field investigation in Jinzhou Bay (JZB), North China in 2010. The chemical results showed high concentrations of metals in the sediment of JZB that were ~129 times greater than the local geochemical background. Furthermore, the measured metals exhibited considerably high toxicity potential indicated by sediment quality guidelines (SQGs). The mean SQGs quotients suggested the overall toxicity incidence was >70% in locations neighboring the Wulihe River mouth. Biomonitoring revealed 116 individuals distributed among a mere 6 species, 4 of which were polychaetes, at 33% of the sampling sites. Thus, few benthic organisms were present in the damaged community structures across the region, which was consistent with the extreme metal contamination. Moreover, the sediment quality assessment, in a weight of evidence framework, demonstrated that the sediment throughout the entire JZB was moderately to severely impaired, especially in the vicinity of the Wulihe River mouth. By synthesizing the present and previous chemical-biological monitoring campaigns, a possible cause-effect relationship between chemical stressors and benthic receptors was established. We also found that the hydrodynamics, sediment sources, and geochemical characteristics of the metals (in addition to the sources of the metals) were responsible for the geochemical distribution of metals in JZB. The significance of the overall finding is that the deleterious responses observed at the community level may possibly be linked to the extreme chemical stress in the sediment of JZB. PMID:26994798

  1. The Chesapeake Bay Impact Crater: An Educational Investigation for Students into the Planetary Impact Process and its Environmental Consequences

    Science.gov (United States)

    Levine, Arlene S.

    2008-01-01

    Planetary impact craters are a common surface feature of many planetary bodies, including the Earth, the Moon, Mars, Mercury, Venus, and Jupiter s moons, Ganymede and Callisto. The NASA Langley Research Center in Hampton, VA, is located about 5 km inside the outer rim of the Chesapeake Bay Impact Crater. The Chesapeake Bay Impact Crater, with a diameter of 85 km is the sixth largest impact crater on our planet. The U.S. Geological Survey (USGS), in collaboration with the NASA Langley Research Center, the Virginia Department of Environmental Quality (VDEQ), the Hampton Roads Planning District Commission (HRPDC), and the Department of Geology of the College of William and Mary (WM) drilled into and through the crater at the NASA Langley Research Center and obtained a continuous core to a depth of 2075.9 ft (632.73 meters) from the Chesapeake Bay Impact Crater. At the NASA Langley location, the granite basement depth was at 2046 ft (623.87 meters). This collaborative drilling activity provided a unique educational opportunity and ongoing educational partnership between USGS, NASA Langley and the other collaborators. NASA Langley has a decade-long, ongoing educational partnership with the Colonial Coast Council of the Girl Scouts. The core drilling and on site analysis and cataloguing of the core segments provided a unique opportunity for the Girl Scouts to learn how geologists work in the field, their tools for scientific investigation and evaluation, how they perform geological analyses of the cores in an on-site tent and learn about the formation of impact craters and the impact of impacting bodies on the sub-surface, the surface, the oceans and atmosphere of the target body. This was accomplished with a two-part activity. Girl Scout day camps and local Girl Scout troops were invited to Langley Research Center Conference Center, where more than 300 Girl Scouts, their leaders and adult personnel were given briefings by scientists and educators from the USGS, NASA

  2. Containment Structure Monitoring And Prestress Losses. Experience from Daya Bay Nuclear Power Plant

    International Nuclear Information System (INIS)

    This article describes the main characteristics of the containment structure of the Guangdong Nuclear Power Station (GNPS), located in Daya Bay, its monitoring devices for containment deformations, the measurement method, data treatment for prestress losses, and result assessment of the tendon relaxation

  3. Impacts of mariculture practices on the temporal distribution of macrobenthos in Sandu Bay, South China

    Science.gov (United States)

    Zhou, Jin

    2012-05-01

    Sandu Bay is located in the East China Sea and is characterized by high-density fish farming and kelp culture. Despite this, little is known about the impacts of these different mariculture practices on the local environment. We investigated the temporal variation in macrobenthos and environmental conditions at three sites in the bay (fish farming site, kelp culture site, and a control site). We collected water and sediment samples during nine cruises between May 2009 and February 2010. The density of macrobenthos peaked at the fish farming site in July (655 ind./m2) whereas density did not fluctuate as widely at the other two sites. Biomass varied significantly at both the control and kelp culture sites, but had only a single peak at the fish farming site in June (21.90 g/m2). The dominant species varied throughout the study period at the control and kelp culture sites, whereas a single terebellid species ( Lysilla pacifica) dominated the macrobenthos at the fish farming site. The diversity index H' increased at the control site beginning in February then decreased after May, whereas H' was low at the other sites in December. The mean dissolved oxygen level was highest at the control site (6.59 mg/L) and lowest at the fish farming site (5.54 mg/L). DO levels were lowest at all sites in summer (July and August). The sediment acid volatile sulfide content was higher at the fish farming site (1.46 mg/g dry weight) than those at the kelp culture and control sites (1.22 and 0.14 mg/g, respectively). Our results suggest that mariculture practices have a clear impact on the benthic environment/community in Sandu Bay.

  4. Impact of hydrotalcite deposition on biogeochemical processes in a shallow tropical bay.

    Science.gov (United States)

    Alongi, Daniel M; McKinnon, A David

    2011-03-01

    The biogeochemistry of a tropical shoal bay (Melville Bay, Australia) impacted by the effluent release, precipitation, and deposition of hydrotalcite from an alumina refinery was studied in both wet and dry seasons. Within the deposition zone, sulfate reduction dominated benthic carbon cycling accounting for ≈100% of total microbial activity, with rates greater than those measured in most other marine sediments. These rapid rates of anoxic metabolism resulted in high rates of sulfide and ammonium production and low C:S ratios, implying significant preservation of S in stable sulfide minerals. Rates of total microbial activity were significantly less in control sediments of equivalent grain size, where sulfate reduction accounted for ≈50% of total benthic metabolism. Rates of planktonic carbon cycling overlying the deposition zone were also greater than those measured in the control areas of southern Melville Bay. At the sediment surface, productive algal and cyanobacterial mats helped stabilize the sediment surface and oxidize sulfide to sulfate to maintain a fully oxygenated water-column overlying the impacted zone. The mats utilized a significant fraction of dissolved inorganic N and P released from the sea bed; some nutrients escaped to the water-column such that benthic regeneration of NH₄+ and PO₄³⁻ accounted for 100% and 42% of phytoplankton requirements for N and P, respectively. These percentages are high compared to other tropical coastal environments and indicate that benthic nutrient recycling may be a significant factor driving water-column production overlying the deposition zone. With regard to remediation, it is recommended that the sea bed not be disturbed as attempts at removal may result in further environmental problems and would require specific assessment of the proposed removal process. PMID:21176952

  5. Impacts of sea-level rise on estuarine circulation: An idealized estuary and San Francisco Bay

    Science.gov (United States)

    Chua, Vivien P.; Xu, Ming

    2014-11-01

    Estuaries lie at the interface of land and sea, and are particularly vulnerable to sea-level rise due to climate change that might lead to intrusion of salt water further upstream and affect circulation patterns. Climate change is also likely to have a major impact on hydrological cycles and consequently lead to changes in freshwater inflows into estuaries. An idealized estuary model is employed to investigate the effects of sea-level rise and freshwater inflows on estuarine circulation. Rising sea levels result in a stronger longitudinal salinity gradient ∂s/∂x, indicating an increase in the strength of the gravitational circulation UGC, higher longitudinal dispersion coefficients K and enhanced salinity intrusion. Under low-flow conditions, the effects of sea level rise on salinity intrusion are largest because sea-level rise has a greater impact due to weaker vertical stratification. Strong flows increase the strength of the gravitational circulation, resulting in higher vertical stratification, which leads to the nonlinear feedback between vertical mixing and stratification. The effect of sea-level rise on salinity intrusion is reduced owing to the suppression of mixing by stratification. Supporting three-dimensional simulations from northern San Francisco Bay are presented. The intrusion length scale L is used as a substitute for regulating inflows to ensure that sufficient fresh water is available to flush the Bay. Following a set of standards explicitly stated in the 1994 Bay-Delta Accord, a series of simulations is performed and we find that with sea-level rise stronger inflows are required to maintain L at the proposed locations.

  6. Impacts of mariculture practices on the temporal distribution of macrobenthos in Sandu Bay, South China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jin

    2012-01-01

    Sandu Bay is located in the East China Sea and is characterized by high-density fish farming and kelp culture.Despite this,little is known about the impacts of these different mariculture practices on the local environment.We investigated the temporal variation in macrobenthos and environmental conditions at three sites in the bay (fish farming site,kelp culture site,and a control site).We collected water and sediment samples during nine cruises between May 2009 and February 2010.The density ofmacrobenthos peaked at the fish farming site in July (655 ind./m2) whereas density did not fluctuate as widely at the other two sites.Biomass varied significantly at both the control and kelp culture sites,but had only a single peak at the fish farming site in June (21.90 g/m2).The dominant species varied throughout the study period at the control and kelp culture sites,whereas a single terebellid species (Lysilla pacifica) dominated the macrobenthos at the fish farming site.The diversity index H' increased at the control site beginning in February then decreased after May,whereas H' was low at the other sites in December.The mean dissolved oxygen level was highest at the control site (6.59 mg/L) and lowest at the fish farming site (5.54 mg/L).DO levels were lowest at all sites in summer (July and August).The sediment acid volatile sulfide content was higher at the fish farming site (1.46 mg/g dry weight) than those at the kelp culture and control sites (1.22 and 0.14 mg/g,respectively).Our results suggest that mariculture practices have a clear impact on the benthic environment/ community in Sandu Bay.

  7. Effects of erosion control structures along a portion of the northern Chesapeake Bay shoreline

    Science.gov (United States)

    Zabawa, C.F.; Kerhin, R.T.; Bayley, S.

    1981-01-01

    A 6.500-meter reach of western Chesapeake Bay shoreline (lower Mayo Peninsula) lost about 1.1??106 cubic meters of sediment (equivalent to 170 cubic meters lost per meter of shoreline) between 1846 and 1932, when the first aerial photographs show the shoreline already substantially protected by a system of groins and intermittent bulkheading. These structures have eliminated the fastland as a source of erodable material, and have starved the supply of sand for littoral drift, thus limiting the extent of the beaches to the remaining groin fields. Volumes of sediment involved in these impacts are small in the overall sediment budget. Bulkheads produce no deficit in the budget since scouring of the beaches on their seaward sides makes up for the decreased erosion of protected fastland. Groins trap little of the potential littoral drift (computed to be about 104 cubic meters per meter of shoreline per year). The sand supply in the remaining beaches is nearly equivalent to the annual loss of sediment from the entire shoreline system due to the long-term rate of erosion of the shoreline and nearshore between 1846 and 1932. ?? 1981 Springer-Verlag New York Inc.

  8. Adapting Bayes Network Structures to Non-stationary Domains

    DEFF Research Database (Denmark)

    Nielsen, Søren Holbech; Nielsen, Thomas Dyhre

    2008-01-01

    When an incremental structural learning method gradually modifies a Bayesian network (BN) structure to fit a sequential stream of observations, we call the process structural adaptation. Structural adaptation is useful when the learner is set to work in an unknown environment, where a BN is gradu......When an incremental structural learning method gradually modifies a Bayesian network (BN) structure to fit a sequential stream of observations, we call the process structural adaptation. Structural adaptation is useful when the learner is set to work in an unknown environment, where a BN...

  9. Structural setting of the Bay of Naples (Italy) seismic reflection data: implications for Campanian volcanism

    Science.gov (United States)

    Bruno, Pier Paolo G.; Rapolla, Antonio; Di Fiore, Vincenzo

    2003-09-01

    This paper focuses on the recent tectonic evolution of the Bay of Naples with the aim of exploring the connection between local tectonics and volcanism. We reprocessed the seismic reflection dataset acquired in the area in the late 1973. The new processing was highly successful in obtaining a decisive strong reduction of random noise, removal of coherent noise and reduction of spatial aliasing. Classical interpretative schemes and complex attributes of seismic traces were used to reconstruct fault kinematics and reflector patterns. The results show that the faults affecting the Bay of Naples exhibit prevailing NE structural strikes, with the exception of the Pozzuoli Caldera where NW patterns are also common. Many faults are subvertical and show seismic evidence of volcanic activity along them. A main alignment of conjugate NE-SW faults, named here as "Magnaghi-Sebeto line", intersects several submarine volcanic banks and separates the bay into two sectors, characterized by important geological, geophysical and petrochemical differences. The structural configuration of the bay may reflect the occurrence of either oblique extension or a transfer zone of the NW-SE fault system, along which, in the Campanian-Lucanian Apennine chain, great vertical displacements occur.

  10. Bay in Flux: Marine Climate Impacts, Art and Tablet App Design

    Science.gov (United States)

    Kintisch, E. S.

    2012-12-01

    Bay in Flux is a year-long experimental effort to design and develop interactive tablet computer apps exploring the marine impacts of climate change. The goal is to convey, visualize and enliven scientific ideas around this topic, while engaging a broad audience through the design of interactive content. Pioneering new models of scientist-artist collaborations are a central part of the effort as well. The project begins with an innovative studio class at the Rhode Island School of Design (RISD) called Bay in Flux, taught in the Fall 2012 semester. Its three instructor team includes two artist-designers and one science reporter, with active collaborations from affiliated marine scientists. The subject matter focus is the Narragansett Bay, which has shown physical, chemical and ecological impacts of climate change, along with the ongoing efforts of researchers to explain and characterize it. In exploring this rich story, we intend to innovate pioneering means of handling narrative material on interactive e-books, enable data collection by citizen scientists or devise game-like simulations to enable audiences to explore and understand complex natural systems. The lessons we seek to learn in this project include: how to effectively encourage collaborations between scientists and designers around digital design; how to pioneer new and compelling ways to tell science-based nonfiction stories on tablets; and how art and design students with no scientific training can engage with complex scientific content effectively. The project will also challenge us to think about the tablet computer not only as a data output device -- in which the user reads, watches, or interacts with provided content -- but also as a dynamic and ideal tool for mobile data input, enabling citizen science projects and novel connections between working researchers and the public. The intended audience could include high school students or older audiences who currently eschew science journalism. HTML5

  11. Numerical Modeling of the Impact of the River Runoff on the Formation of the Anoxia in the Kangjin Bay, South Sea, Korea

    Science.gov (United States)

    Ro, Y.

    2005-05-01

    boundaries. Because of the three open channels, the current distribution varies remarkably depending on the location inside the Bay. The tidal residual current patterns show the eddy structures developed near the mouth of the three channels which would have significant impact on the local water quality and ecosystem. Implications for the local ecosystem The circulation is driven by the tidal current most of the year except in the summer season when river runoffs from inflowing two rivers affect the salinity distribution and thereby density current is generated. One of the critical conditions in the Bay is dissolved oxygen contents which exhibit hypoxic conditions in the summer season (June, July and August) when water temperature is very high above 25 deg C and stratification is strong which inhibit the vertical supply of oxygen from the air. It is also considered that the critical bottom shear stress plays an important role in the hypoxic condition by resuspending the organic-rich bottom sediment into the water column which then consumes the oxygen. This study will illucidate the one of the mechnanism which will cause the hypoxic condition by the strong pycnocline formed by the river runoffs in the summer monsoon. The massive death rates of the large arc sheel in the summer might be attributed by the hypoxia formed by the river runoff.

  12. Assessment of the impact of oil spill on Mumbai harbor bay

    International Nuclear Information System (INIS)

    On 7 th August, 2010 two cargo ships MSC Chitra and MV Khalijia collided off Mumbai coast causing an oil spill that spread quickly through Maharashtra's coastline. MSC Chitra ruptured its tank when it hit incoming MV Khalijia. MSC Chitra tilted to about 80 degrees soon after the collision, spilling an estimated 400 to 500 tonnes of oil. The ship was loaded with an estimated 2,600 tonnes of oil, 300 tonnes of diesel and 70 tonnes of lubricating oil at the time of the accident. The oil spill has spreaded over an area of 25 square kilometers. MSC Chitra was carrying 1219 containers out of which 31 had hazardous chemicals like organophosphate pesticides. After the collision about 400 containers fall off into to the sea from the deck of MSC Chitra. The oil spill has resulted in severe environmental damage along the Mumbai coastline as well as to the marine life. In order to assess the impact of oil spill on the marine environment daily monitoring of oil and grease levels has been carried out at CIRUS Jetty. Additionally three field surveys have been carried out along the coast line of Mumbai harbor bay from Vashi Jetty to Uran collecting sea water samples. The samples collected at CIRUS Jetty and Mumbai harbor bay are analyzed for various water quality parameters apart from oil and grease. The results indicate the oil and grease levels in sea water at CIRUS Jetty reduced to background levels within 15 days. The filed survey along Mumbai harbor bay also shows a decreasing trend in the oil and grease levels in seawater. (author)

  13. Seasonal variations in phytoplankton community structure in the Sanggou, Ailian, and Lidao Bays

    Science.gov (United States)

    Yuan, Mingli; Zhang, Cuixia; Jiang, Zengjie; Guo, Shujin; Sun, Jun

    2014-12-01

    The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay (SGB) and the adjacent Ailian Bay (ALB) and Lidao Bay (LDB) in Shandong Peninsula, eastern China. The species composition and cell abundance of phytoplankton in the bay waters in spring (April 2011), summer (August 2011), autumn (October 2011), and winter (January 2012) were examined using the Utermöhl method. A total of 80 taxa of phytoplankton that belong to 39 genera of 3 phyla were identified. These included 64 species of 30 genera in the Phylum Bacillariophyta, 13 species of 8 genera in the Phylum Dinophyta, and 3 species of 1 genus in the Phylum Chrysophyta. During the four seasons, the number of phytoplankton species (43) was the highest in spring, followed by summer and autumn (40), and the lowest number of phytoplankton species (35) was found in winter. Diatoms, especially Paralia sulcata (Ehrenberg) Cleve and Coscinodiscus oculus-iridis Ehrenberg, were predominant in the phytoplankton community throughout the study period, whereas the dominance of dinoflagellate appeared in summer only. The maximum cell abundance of phytoplankton was detected in summer (average 8.08 × 103 cells L-1) whereas their minimum abundance was found in autumn (average 2.60 × 103 cells L-1). The phytoplankton abundance was generally higher in the outer bay than in the inner bay in spring and autumn. In summer, the phytoplankton cells were mainly concentrated in the south of inner SGB, with peak abundance observed along the western coast. In winter, the distribution of phytoplankton cells showed 3 patches, with peak abundance along the western coast as well. On seasonal average, the Shannon-Wiener diversity indices of phytoplankton community ranged from 1.17 to 1.78 (autumn > summer > spring > winter), and the Pielou's evenness indices of phytoplankton ranged from 0.45 to 0.65 (autumn > spring > summer > winter). According to the results of canonical correspondence analysis

  14. Flood impacts in Keppel Bay, southern great barrier reef in the aftermath of cyclonic rainfall.

    Science.gov (United States)

    Jones, Alison M; Berkelmans, Ray

    2014-01-01

    In December 2010, the highest recorded Queensland rainfall associated with Tropical Cyclone 'Tasha' caused flooding of the Fitzroy River in Queensland, Australia. A massive flood plume inundated coral reefs lying 12 km offshore of the Central Queensland coast near Yeppoon and caused 40-100% mortality to coral fringing many of the islands of Keppel Bay down to a depth of ∼8 m. The severity of coral mortality was influenced by the level of exposure to low salinity seawater as a result of the reef's distance from the flood plume and to a lesser extent, water depth and whether or not the reef faced the plume source. There was no evidence in this study of mortality resulting from pollutants derived from the nearby Fitzroy Catchment, at least in the short term, suggesting that during a major flood, the impact of low salinity on corals outweighs that of pollutants. Recovery of the reefs in Keppel Bay from the 2010/2011 Fitzroy River flood is likely to take 10-15 years based on historical recovery periods from a similar event in 1991; potentially impacting visitor numbers for tourism and recreational usage. In the meantime, activities like snorkeling, diving and coral viewing will be focused on the few shallow reefs that survived the flood, placing even further pressure on their recovery. Reef regeneration, restoration and rehabilitation are measures that may be needed to support tourism in the short term. However, predictions of a warming climate, lower rainfall and higher intensity summer rain events in the Central and Coastal regions of Australia over the next decade, combined with the current anthropogenic influences on water quality, are likely to slow regeneration with consequent impact on long-term reef resilience. PMID:24427294

  15. Flood impacts in Keppel Bay, southern great barrier reef in the aftermath of cyclonic rainfall.

    Directory of Open Access Journals (Sweden)

    Alison M Jones

    Full Text Available In December 2010, the highest recorded Queensland rainfall associated with Tropical Cyclone 'Tasha' caused flooding of the Fitzroy River in Queensland, Australia. A massive flood plume inundated coral reefs lying 12 km offshore of the Central Queensland coast near Yeppoon and caused 40-100% mortality to coral fringing many of the islands of Keppel Bay down to a depth of ∼8 m. The severity of coral mortality was influenced by the level of exposure to low salinity seawater as a result of the reef's distance from the flood plume and to a lesser extent, water depth and whether or not the reef faced the plume source. There was no evidence in this study of mortality resulting from pollutants derived from the nearby Fitzroy Catchment, at least in the short term, suggesting that during a major flood, the impact of low salinity on corals outweighs that of pollutants. Recovery of the reefs in Keppel Bay from the 2010/2011 Fitzroy River flood is likely to take 10-15 years based on historical recovery periods from a similar event in 1991; potentially impacting visitor numbers for tourism and recreational usage. In the meantime, activities like snorkeling, diving and coral viewing will be focused on the few shallow reefs that survived the flood, placing even further pressure on their recovery. Reef regeneration, restoration and rehabilitation are measures that may be needed to support tourism in the short term. However, predictions of a warming climate, lower rainfall and higher intensity summer rain events in the Central and Coastal regions of Australia over the next decade, combined with the current anthropogenic influences on water quality, are likely to slow regeneration with consequent impact on long-term reef resilience.

  16. Impact of storm-water outfalls on sediment quality in Corpus Christi Bay, Texas, USA

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.S.; Montagna, P.A.; Biedenbach, J.M.; Kalke, R.; Kennicutt, M.C.; Hooten, R.; Cripe, G.

    2000-03-01

    To determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm-water outfalls, but 13 other sites (i.e., industrial and domestic outfalls, oil field-produced water discharges, and dredging activity) and eight reference sites were also evaluated. Sediment samples were collected and analyzed for physical-chemical characteristics, contaminant concentrations (metals, polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and pesticides), toxicity, and a benthic index of biotic integrity (BIBI) composed of 10 independent metrics calculated for each site. This large data matrix was reduced using multivariate analysis to create new variables for each component representing overall means and containing most of the variance in the larger data set. The new variables were used to conduct the correlation analysis. Toxicity was significantly correlated with both chemistry and ecological responses, whereas no correlations between the benthic metrics and sediment chemistry were observed. Using the combined information from the SQT, four of the five most degraded sites were storm-water outfall sites. Although estuaries are naturally stressful environments because of salinity and temperature fluctuations, this ecosystem appears to have been compromised by anthropogenic influences similar to what has been observed for other heavily urbanized bay systems along the Texas and Gulf coast.

  17. The increasing impact of food production on nutrient export by rivers to the Bay of Bengal 1970–2050

    NARCIS (Netherlands)

    Sattar, M.A.; Kroeze, C.; Strokal, M.

    2014-01-01

    The objective of this study is to assess the impact of food production on river export of nutrients to the coastal waters of the Bay of Bengal in the past (1970 and 2000) and the future (2030 and 2050), and the associated potential for coastal eutrophication. We model nutrient export from land to se

  18. Impact of continental outflow on chemistry of atmospheric aerosols over tropical Bay of Bengal

    Science.gov (United States)

    Srinivas, B.; Kumar, A.; Sarin, M. M.; Sudheer, A. K.

    2011-07-01

    The continental outflow from Indo-Gangetic Plain and south-east Asia dominates the widespread dispersal of pollutants over tropical Bay of Bengal (BoB) during the late NE-monsoon (January-March). It is thus pertinent to assess the impact on marine atmospheric boundary layer of BoB. The chemical data, based on analyses of size-segregated (PM2.5 and PM10) aerosols, suggest the dominance of nss-SO42- (range: 1.3 to 28 μg m-3) in PM2.5. Almost all SO42- is of anthropogenic origin and accounts for as much as 65 % of the water-soluble inorganic constituents. The impact of anthropogenic sources is further evident from the widespread depletion of chloride (range: 40 to 100 %) compared to sea-salt composition. The carbonaceous species (EC and OC) contribute nearly 25 % to PM2.5; and significant linear relationship with K+ suggests biomass burning as their dominant source (biofuels and agricultural waste). The enhancement in the fractional solubility of aerosol Fe, as assessed in PM2.5, re-emphasizes the impact of combustion sources (biomass and fossil-fuel) and chemical processing (of dust) during the long-range transport. The high enrichment factors of heavy metals (Pb and Cd) further demonstrate the influence of pollution sources on the chemistry of MABL. The downwind transport of pollutants and exchange across air-sea interface can, thus, have profound impact on the ocean surface biogeochemistry.

  19. Impacts of diverted freshwater on dissolved organic matter and microbial communities in Barataria Bay, Louisiana, U.S.A.

    Science.gov (United States)

    Bianchi, Thomas S; Cook, Robert L; Perdue, E Michael; Kolic, Paulina E; Green, Nelson; Zhang, Yaoling; Smith, Richard W; Kolker, Alexander S; Ameen, Alex; King, Gary; Ojwang, Loice M; Schneider, Caroline L; Normand, Anna E; Hetland, Robert

    2011-12-01

    Here we present results of an initial assessment of the impacts of a water diversion event on the concentrations and chemical composition of dissolved organic matter (DOM) and bacterioplankton community composition in Barataria Bay, Louisiana U.S.A, an important estuary within the Mississippi River Delta complex. Concentrations and spectral properties of DOM, as reflected by UV/visible absorbance and fluorescence, were strikingly similar at 26 sites sampled along transects near two western and two eastern areas of Barataria Bay in July and September 2010. In September 2010, dissolved organic carbon (DOC) was significantly higher (568.1-1043 μM C, x=755.6+/-117.7 μM C, n=14) than in July 2010 (249.1-577.1 μM C, x=383.7+/-98.31 μM C, n=14); conversely, Abs254 was consistently higher at every site in July (0.105-0.314) than in September (0.080-0.221), averaging 0.24±0.06 in July and 0.15±0.04 in September. Fluorescence data via the fluorescence index (FI450/500) revealed that only 30% (8 of 26) of the July samples had an FI450/500 above 1.36, compared to 96% (25 of 26) for the September samples. This indicates a more terrestrial origin for the July DOM. Bacterioplankton from eastern sites differed in composition from bacterioplankon in western sites in July. These differences appeared to result from reduced salinities caused by the freshwater diversion. Bacterioplankton communities in September differed from those in July, but no spatial structure was observed. Thus, the trends in bacterioplankton and DOM were likely due to changes in water masses (e.g., input of Mississippi River water in July and a return to estuarine waters in September). Discharge of water from the Davis Pond Freshwater Diversion (DPFD) through Barataria Bay may have partially mitigated some adverse effects of the oil spill, inasmuch as DOM is concerned. PMID:22000271

  20. Economic impacts of the S.S. Glacier Bay oil spill: Social and economic studies. Technical report (Final)

    International Nuclear Information System (INIS)

    On July 2, 1987, an oil spill occurred in Cook Inlet when the S.S. Glacier Bay hit a submerged obstacle while enroute to Kenai Pipeline Company facilities to offload oil. The 1987 commercial fishery in Cook Inlet was barely underway when the S.S. Glacier Bay oil spill occurred, and the largest salmon return in history was moving up the inlet. The sockeye salmon run alone totaled over 12 million, providing a seasonal catch of 9.25 million salmon. The 1987 sport fishery in Cook Inlet was in mid-season at the time of the spill. The S.S. Glacier Bay oil spill represents an opportunity to study the economic impacts of an oil spill event in Alaska, particularly with regard to commercial fishing impacts and the public costs of cleanup. The report evaluates the existing information on the spill, response measures, and economic impacts, and adds discussions with individuals and groups involved in or affected by the spill to this data base. The report reviewed accounts of the oil spill and its costs; identified types and sources of data, developed protocol, and contacted groups and people for data collection and verification; and described, analyzed, and prepared reports of the economic effects of the S.S. Glacier Bay oil spill

  1. Biological impact of eutrophication in the bay of somme and the induction and impact of anoxia

    Science.gov (United States)

    Desprez, M.; Rybarczyk, H.; Wilson, J. G.; Ducrotoy, J. P.; Sueur, F.; Olivesi, R.; Elkaim, B.

    The first effects of eutrophication in the Bay of Somme became apparent in the years 1982-1985, when the cockle population collapsed. Areas of high mortality were mapped. Following exceptionally high summer temperatures, other effects were seen in 1982, 1983 and 1989, notably a mass mortality of the benthos. It appeared that the mortality of the benthos was a direct result of anoxia in the water promoted by phytoplankton blooms which were due to high nitrogen levels (nitrates from river and land runoff; ammonium from estuarine bivalve populations). Effects from the change in the benthic community (the disappearance of Cerastoderma edule and the proliferation of Pygospio elegans) were also apparent higher up in the food chain, viz. changes in the diet of the two main predators of the bivalve, the oystercatcher ( Haematopus ostralegus) and the common gull ( Larus canus). Following respirometry measurements of the water, sediment and the major macrobenthic species ( Cerastoderma edule, Macoma balthica, Nereis diversicolor, Hydrobia ulvae), a model for anoxia was constructed.

  2. Missile impact on structural members

    International Nuclear Information System (INIS)

    In this paper, a unified methodology will be developed to evaluate impact effects of hard missiles on reinforced concrete and steel members including plates/walls and beams. The solution will be investigated based on two ultimate limit states: local perforation and structural collapse of flexible plates and beams

  3. Impact of continental outflow on chemistry of atmospheric aerosols over tropical Bay of Bengal

    Directory of Open Access Journals (Sweden)

    B. Srinivas

    2011-07-01

    Full Text Available The continental outflow from Indo-Gangetic Plain and south-east Asia dominates the widespread dispersal of pollutants over tropical Bay of Bengal (BoB during the late NE-monsoon (January–March. It is thus pertinent to assess the impact on marine atmospheric boundary layer of BoB. The chemical data, based on analyses of size-segregated (PM2.5 and PM10 aerosols, suggest the dominance of nss-SO42− (range: 1.3 to 28 μg m−3 in PM2.5. Almost all SO42− is of anthropogenic origin and accounts for as much as 65 % of the water-soluble inorganic constituents. The impact of anthropogenic sources is further evident from the widespread depletion of chloride (range: 40 to 100 % compared to sea-salt composition. The carbonaceous species (EC and OC contribute nearly 25 % to PM2.5; and significant linear relationship with K+ suggests biomass burning as their dominant source (biofuels and agricultural waste. The enhancement in the fractional solubility of aerosol Fe, as assessed in PM2.5, re-emphasizes the impact of combustion sources (biomass and fossil-fuel and chemical processing (of dust during the long-range transport. The high enrichment factors of heavy metals (Pb and Cd further demonstrate the influence of pollution sources on the chemistry of MABL. The downwind transport of pollutants and exchange across air-sea interface can, thus, have profound impact on the ocean surface biogeochemistry.

  4. San Diego Bay National Wildlife Refuge: Sweetwater Marsh and South San Diego Bay Units: Comprehensive Conservation Plan and Environmental Impact Statement: Volume I

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on San Diego Bay NWR (Sweetwater Marsh and South San Diego Bay Units) for the next 15...

  5. Study and review on crust-mantle velocity structure in Bohai Bay and its vicinity

    Institute of Scientific and Technical Information of China (English)

    张成科; 张先康; 赵金仁; 任青芳; 张建狮; 海燕

    2002-01-01

    Observational data from some of the 10-odd deep seismic sounding profiles in Bohai Bay and its adjacent areas were processed with the methods of two-dimensional ray tracing, travel-time fitting and synthetic seismogram. The crust and upper-mantle velocity structure model in this area was built. The results show that the crust and upper mantle structures present obvious lateral and vertical inhomogeneity. The upper mantle uplifts near Yongqing of northeast Jizhong depression, in Bohai Bay of Huanghua depression and near Kenli of Jiyang depression, where crustal depths are about 31 km, 28 km and 29 km, respectively. According to the dynamic and kinetic characteristics of seismic waves as well as the seismic interfaces and velocity contour undulation in the 2-D velocity structure model, three deep crustal fault zones are inferred in the area. Low velocity (5.90~6.10 km/s) layers (bodies) exist on one or two sides of these deep crustal fault zones.

  6. Seismically induced soft-sediment deformation structures in the Palaeogene deposits of the Liaodong Bay Depression in the Bohai Bay basin and their spatial stratigraphic distribution

    Science.gov (United States)

    Liu, Lei; Zhong, Yijiang; Chen, Hongde; Xu, Changgui; Wu, Kui

    2016-08-01

    Soft-sediment deformation structures (SSDS) have been identified from well cores in the Palaeogene deposits of the Liaodong Bay Depression in the Bohai Bay basin, China. These deposits formed as interbedded sand and mud at a delta front or on the slope toe of the prodelta. According to criteria proposed by previous research, we established that these SSDS were induced by earthquakes and that they can be divided into two groups: ductile deformation structures (plastic intrusions, ball-and-pillow structures, flame structures, boudinage structures, irregular convolute stratifications, and synsedimentary faults and folds) and brittle deformation structures (sand dykes and autoclastic breccias). Based on their level of deformation, size, and complexity, the SSDS were divided into three Groups, from weak to strong, to reflect the intensity of palaeo-earthquakes. With consideration of the palaeo-sedimentary environment, we proposed a model to account for the production and preservation of these SSDS. According to the classification adopted in this study and the spatial stratigraphic distribution of the SSDS, the tectonic activities of the Tan-Lu faults in the Bohai Bay basin were investigated. The A and B oilfields (assumed names) are located in the tectonically active zones of the west and east branches of these faults, respectively. The extension tectonic activities in the A oilfield region exhibit a sharply decreasing trend from E2s3 to E2s1, and increase again in E3d2; whereas the strike-slip tectonic activities in the B oilfield region exhibit an increasing trend from E2s3 to E2s1, and finally, reach a maximum to E3d3. The results of this study show that the method of analysis of the spatial stratigraphic distribution of SSDS is suitable for determining the evolution of tectonic activity and thus, it can provide a new perspective for basin analysis.

  7. 77 FR 33213 - An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska-Peer Review...

    Science.gov (United States)

    2012-06-05

    ...EPA is announcing the peer review panel members assembled by an independent contractor to evaluate the draft document titled, ``An Assessment of Potential Mining Impacts on Salmon Ecosystems of Bristol Bay, Alaska'' (EPA-910-R-12-004a-c). EPA is also announcing a three week public comment period for the draft charge questions to be provided to the peer review panel. The assessment was prepared......

  8. An analysis of urban development and its environmental impact on the Tampa Bay watershed

    Science.gov (United States)

    Xian, G.; Crane, M.; Su, J.

    2007-01-01

    Urbanization has transformed natural landscapes into anthropogenic impervious surfaces. Urban land use has become a major driving force for land cover and land use change in the Tampa Bay watershed of west-central Florida. This study investigates urban land use change and its impact on the watershed. The spatial and temporal changes, as well as the development density of urban land use are determined by analyzing the impervious surface distribution using Landsat satellite imagery. Population distribution and density are extracted from the 2000 census data. Non-point source pollution parameters used for measuring water quality are analyzed for the sub-drainage basins of Hillsborough County. The relationships between 2002 urban land use, population distribution and their environmental influences are explored using regression analysis against various non-point source pollutant loadings in these sub-drainage basins. The results suggest that strong associations existed between most pollutant loadings and the extent of impervious surface within each sub-drainage basin in 2002. Population density also exhibits apparent correlations with loading rates of several pollutants. Spatial variations of selected non-point source pollutant loadings are also assessed. ?? 2006 Elsevier Ltd. All rights reserved.

  9. Tourism Impacts and Support for Tourism Development in Ha Long Bay, Vietnam: An Examination of Residents’ Perceptions

    Directory of Open Access Journals (Sweden)

    Pham Hong Long

    2012-06-01

    Full Text Available The impacts of tourism have been given much attention by scholars attempting to examine the perceptions as well as attitudes of the local residents toward tourism. Such studies have been carried out thoroughly in the context of the developed countries. However, very little research has been carried out in developing countries. This study attempts to make a little contribution to the sustainable development of tourism by examining the residents’ profile, perceptions and attitudes towards tourism impacts and tourism development in Ha Long Bay, the Vietnam’s first World Heritage Site (recognized in 1994. Data were collected by means of a questionnaire study. Based on 417 respondents surveyed, the findings show that the majority of respondents were young, Kinh rather than other ethnic group, they were married and were living in Ha Long Bay for over 20 years. On the whole, respondents viewed tourism positively and would support tourism development. They were generally in favor of tourism that contributes economically and socio-culturally to Ha Long Bay. They were, however, slightly ambivalent to environmental impacts of tourism. Implications, policy recommendations and limitations of study are presented in the conclusion.

  10. Structural vulnerability and problem drinking among Latino migrant day laborers in the San Francisco Bay Area.

    Science.gov (United States)

    Worby, Paula A; Organista, Kurt C; Kral, Alex H; Quesada, James; Arreola, Sonya; Khoury, Sahar

    2014-08-01

    Latino migrant day laborers (LMDLs) live under challenging conditions in the San Francisco Bay Area. This study explored day laborer alcohol use guided by a structural vulnerability framework, specifically problem vs. non-problem drinking as perceived by LMDLs and how they cope with or try to avoid problem drinking given their broader environment. The study utilized ethnographic methods including in-depth semi-structured qualitative interviews with 51 LMDLs. Findings revealed the considerable challenge of avoiding problem drinking given socio-environmental factors that influence drinking: impoverished living and working conditions, prolonged separation from home and family, lack of work authorization, consequent distress and negative mood states, and peer pressure to drink. While participants shared strategies to avoid problem drinking, the success of individual-level efforts is limited given the harsh structural environmental factors that define day laborers' daily lives. Discussed are implications for prevention and intervention strategies at the individual, community, national and international levels. PMID:25130240

  11. Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

    Science.gov (United States)

    Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.; Diskin, Glenn S.; Dickerson, Russell R.

    2014-01-01

    Meteorological and air-quality model simulations are analyzed alongside observations to investigate the role of the Chesapeake Bay breeze on surface air quality, pollutant transport, and boundary layer venting. A case study was conducted to understand why a particular day was the only one during an 11-day ship-based field campaign on which surface ozone was not elevated in concentration over the Chesapeake Bay relative to the closest upwind site and why high ozone concentrations were observed aloft by in situ aircraft observations. Results show that southerly winds during the overnight and early-morning hours prevented the advection of air pollutants from the Washington, D.C., and Baltimore, Maryland, metropolitan areas over the surface waters of the bay. A strong and prolonged bay breeze developed during the late morning and early afternoon along the western coastline of the bay. The strength and duration of the bay breeze allowed pollutants to converge, resulting in high concentrations locally near the bay-breeze front within the Baltimore metropolitan area, where they were then lofted to the top of the planetary boundary layer (PBL). Near the top of the PBL, these pollutants were horizontally advected to a region with lower PBL heights, resulting in pollution transport out of the boundary layer and into the free troposphere. This elevated layer of air pollution aloft was transported downwind into New England by early the following morning where it likely mixed down to the surface, affecting air quality as the boundary layer grew.

  12. Earthquake and human impact on the sedimentology and geochemistry of Ahuriri Estuary, Hawke's Bay

    International Nuclear Information System (INIS)

    Three cores were collected from the intertidal and salt marsh sediments in Ahuriri Estuary, Hawke's Bay, and analysed by sedimentological, chemical and geochronological techniques. Signatures of various events, of both natural and anthropogenic origin, were identified. Evidence for the 1931 Hawke's Bay earthquake, which resulted in an uplift of one to two metres in the Napier area, is given by a change in grainsize distribution in a core from the southern shore of the Lower Estuary. The change to a high energy environment, similar to the present one in the Lower Estuary, has resulted in deposition of sand over fine silt. The data suggest increased sediment accumulation rates following the uplift event, which might be attributed to increased erosion in the upper catchment. There is no evidence of the earthquake at the two other sites sampled, which is probably due to their more sheltered location in the estuary. Post-European settlement impact is mainly restricted to the Lower Estuary, where increased concentrations of Zn, Cr, Pb and Cu may be due to industrial discharges. Evidence of agricultural runoff is given by an increase in Cu concentrations near the Poraiti Hills. The chemical data (Cl and S) suggest a change in the depositional environment in the Upper Estuary due to increased freshwater influx and/or decrease in seawater influence. Dating by 210Pb infers that this occurred prior to 1931, but the origin and timing of the event are still to be determined. Sediment accumulation rates have averaged 2.5 mm/yr for the last 45 years in the Lower Estuary and 3.8 mm/yr for the last 70 years or so in the Upper Estuary. The variation probably reflects the difference in depositional environment, from a high energy environment dominated by tidal and wave action to a low energy environment with additional organic and fine sediment input from stream runoff. The various signatures identified are based on known events but may be used for identifying events in other less

  13. The impact of changing climate on phenology, productivity, and benthic-pelagic coupling in Narragansett Bay

    Science.gov (United States)

    Nixon, Scott W.; Fulweiler, Robinson W.; Buckley, Betty A.; Granger, Stephen L.; Nowicki, Barbara L.; Henry, Kelly M.

    2009-03-01

    The timing and magnitude of phytoplankton blooms have changed markedly in Narragansett Bay, RI (USA) over the last half century. The traditional winter-spring bloom has decreased or, in many years, disappeared. Relatively short, often intense, diatom blooms have become common in spring, summer, and fall replacing the summer flagellate blooms of the past. The annual and summer mean abundance (cell counts) and biomass (chl a) of phytoplankton appear to have decreased based on almost 50 years of biweekly monitoring by others at a mid bay station. These changes have been related to warming of the water, especially during winter, and to increased cloudiness. A significant decline in the winter wind speed may also have played a role. The changes in the phenology of the phytoplankton and the oligotrophication of the bay appear to have decreased greatly the quantity and (perhaps) quality of the organic matter being deposited on the bottom of the bay. This decline has resulted in a very much reduced benthic metabolism as reflected in oxygen uptake, nutrient regeneration, and the magnitude and direction of the net flux of N 2 gas. Based on many decades of standard weekly trawls carried out by the Graduate School of Oceanography, the winter biomass of bottom feeding epibenthic animals has also declined sharply at the mid bay station. After decades of relatively constant anthropogenic nitrogen loading (and declining phosphorus loading), the fertilization of the bay will soon be reduced during May-October due to implementation of advanced wastewater treatment. This is intended to produce an oligotrophication of the urban Providence River estuary and the Upper Bay. The anticipated decline in the productivity of the upper bay region will probably decrease summer hypoxia in that area. However, it may have unanticipated consequences for secondary production in the mid and lower bay where climate-induced oligotrophication has already much weakened the historically strong benthic

  14. Evolution of nutrient structure and phytoplankton composition in the Jiaozhou Bay ecosystem

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shu-jiang; JIAO Nian-zhi; WU Chang-wen; LIANG Bing; ZHANG Shu-yi

    2005-01-01

    The inventories of nutrients in the surface water and large phytoplankton( > 69 μm) were analyzed from the data set of JERS ecological database about a typical coastal waters, the Jiaozhou Bay, China, from 1960s for N, P and from 1980s for Si. By examining long-term changes of nutrient concentration, calculating stoichiometric balance, and comparing diatom composition, Si limitation of diatom production was found to be more possible. The possibility of Si limitation was from 37% in 1980s to 50% in 1990s. Jiaozhou Bay ecosystem is becoming serious eutrophication, with notable increase of NO2-N, NO3-N and NH4-N from 0.1417 μmol/L, 0.5414 μmol/L,1.7222 μmol/L in 1960s to 0.9551 μmol/L, 3.001 μmol/L, 8.0359 μmol/L in late 1990s respectively and prominent decrease of Si from 4.2614μmol/L in 1980s to 1.5861 μmol/L in late 1990s; the nutrient structure is controlled by nitrogen; the main limiting nutrient is probably silicon;because of the Si limitation the phytoplankton community structure has changed drastically.

  15. Distribution, Ecology and Potential Impacts of the Chinese Mitten Crab (Eriocheir sinensis) in San Francisco Bay

    OpenAIRE

    Rudnick, Deborah A; Halat, Kathleen M; Resh, Vincent H.

    2000-01-01

    The arrival of the Chinese mitten crab to the San Francisco Bay-San Joaquin Delta (Bay- Delta) ecosystem has been a source of widespread concern. This crab has spread from its native range, in China, to coastal ecosystems throughout Europe and, most recently, into North America. The Chinese mitten crab population in California has exploded within the last decade to cover hundreds of miles of the Bay-Delta and its tributaries. The Chinese mitten crab is a large, catadromous crab, moving from f...

  16. New constraints on the crustal structure in the eastern part of northern Baffin Bay

    Science.gov (United States)

    Reichert, C. J.; Damm, V.; Altenbernd, T.; Berglar, K.; Block, M.; Ehrhardt, A.; Schnabel, M.

    2010-12-01

    The northern Baffin Bay is a key area for testing plate kinematic models for the Paleocene-Eocene motion of Greenland relative to North America and to decipher the evolution of the thick sedimentary basins in this area. In summer 2010, a multidisciplinary marine geoscientific expedition focusing on the Greenland part of northern Baffin Bay was performed under the direction of the Federal Institute for Geosciences and Natural Resources Hannover, Germany in cooperation with the Alfred-Wegener Institute Bremerhaven. Using 70 days ship time onboard the German R/V Polarstern a comprehensive data set was acquired along profiles extending from the deep oceanic basin in the central part of North Baffin Bay onto the Greenland continental margin in an area which was bordered by the Kane Basin in the North and Disco Island in the South. By means of multi-channel seismic, wide angle seismic, gravimetric and magnetic methods the structural inventory of the crust in the NW Baffin Bay was investigated. Additionally, heat flow data and sediment cores were collected at selected positions along lines across the Greenland continental margin. The cores were extracted for geochemical and geomicrobiological analysis to be used for basin modeling and studying the hydrocarbon potential. Aeromagnetic data was acquired covering part of the marine survey area to investigate magnetic signatures of the oceanic crust and the continental margin. In our presentation we will give an overview of the first results of the expedition with special focus on multi-channel seismic data. With a total length of 3500 km, the initial interpretation of multi-channel seismic data shows that the West Greenland margin is a typical passive continental margin with large rotated basement blocks, listric faults facing mainly seaward, and deep syn-rift-basins in between. The most prominent reflector under the shelf and the slope probably indicates the transition from rifting to drifting and therefore the beginning of

  17. Attenuation of Storm Surge Flooding By Wetlands in the Chesapeake Bay: An Integrated Geospatial Framework Evaluating Impacts to Critical Infrastructure

    Science.gov (United States)

    Khalid, A.; Haddad, J.; Lawler, S.; Ferreira, C.

    2014-12-01

    Areas along the Chesapeake Bay and its tributaries are extremely vulnerable to hurricane flooding, as evidenced by the costly effects and severe impacts of recent storms along the Virginia coast, such as Hurricane Isabel in 2003 and Hurricane Sandy in 2012. Coastal wetlands, in addition to their ecological importance, are expected to mitigate the impact of storm surge by acting as a natural protection against hurricane flooding. Quantifying such interactions helps to provide a sound scientific basis to support planning and decision making. Using storm surge flooding from various historical hurricanes, simulated using a coupled hydrodynamic wave model (ADCIRC-SWAN), we propose an integrated framework yielding a geospatial identification of the capacity of Chesapeake Bay wetlands to protect critical infrastructure. Spatial identification of Chesapeake Bay wetlands is derived from the National Wetlands Inventory (NWI), National Land Cover Database (NLCD), and the Coastal Change Analysis Program (C-CAP). Inventories of population and critical infrastructure are extracted from US Census block data and FEMA's HAZUS-Multi Hazard geodatabase. Geospatial and statistical analyses are carried out to develop a relationship between wetland land cover, hurricane flooding, population and infrastructure vulnerability. These analyses result in the identification and quantification of populations and infrastructure in flooded areas that lie within a reasonable buffer surrounding the identified wetlands. Our analysis thus produces a spatial perspective on the potential for wetlands to attenuate hurricane flood impacts in critical areas. Statistical analysis will support hypothesis testing to evaluate the benefits of wetlands from a flooding and storm-surge attenuation perspective. Results from geospatial analysis are used to identify where interactions with critical infrastructure are relevant in the Chesapeake Bay.

  18. Impacts to Humboldt Bay NWR from forestry and dairy activities in the Salmon Creek Watershed

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The freshwater creeks, brackish water sloughs, saltwater marshes and mud flats found on the Humboldt Bay National Refuge provide habitats for at least 110 species...

  19. Characterization of toxic impacts on living marine resources in tidal rivers of the Chesapeake Bay

    OpenAIRE

    Fulton, M.H.; Hyland, J. L.; Key, P B; Wirth, E. F.; Balthis, W. L.; Cooksey, C.; K. Chung; Leight, A.K.

    2007-01-01

    In 1999, the Chesapeake Bay Program completed a survey of existing data on chemical contaminants and the potential for bioeffects in 38 tidal river systems of Chesapeake Bay. This review led to the identification of 20 areas for which there were insufficient data to adequately characterize the potential for contaminant bioeffects on the Bay’s living resources. The goal of the present study was to estimate the current status of ecological condition in five of these areas and thus help to...

  20. Contrasting phytoplankton community structure and associated light absorption characteristics of the western Bay of Bengal

    Science.gov (United States)

    Pandi, Sudarsana Rao; Kiran, Rayaprolu; Sarma, Nittala S.; Srikanth, A. S.; Sarma, V. V. S. S.; Krishna, M. S.; Bandyopadhyay, D.; Prasad, V. R.; Acharyya, T.; Reddy, K. G.

    2014-01-01

    Absorption spectra, particulate pigments, and hydrochemical constituents were measured in the western Bay of Bengal (BoB) during July-August 2010 when influence of river discharge is at peak. Chromophoric dissolved organic matter (CDOM) absorption coefficient (aCDOM(440)) displayed a significant inverse linear relationship with salinity in the surface waters implying conservative mixing of marine and terrestrial end members. The northern part of the study area is influenced by discharge from the river Ganga and a dominant terrestrial CDOM signal is seen. The southern part receives discharge from peninsular rivers with corresponding signals of higher CDOM than the linear model would indicate and higher UV-specific absorption coefficient (SUVA) indicating more aged and humified DOM. Lower contribution of CDOM to total non-water absorption and higher phytoplankton biomass (chlorophyll a absorption coefficient, aph(440)) but lower chlorophyll a specific phytoplankton absorption coefficient (a{ph/*}(440)) characterize the northern part, compared to the southern part. Chlorophyll b had a distinct linear relationship with chlorophyll a in the latter. The size index (SI) indicated dominance of microphytoplankton in the northern and nano and picophytoplankton in the southern parts. Chlorophyll a is significantly related to a{ph/*}(440) by an inverse power model in the northern part but by an inverse linear model in the southern part. Our study suggests that knowledge of the phytoplankton community structure is essential to improve chlorophyll a algorithm in the coastal Bay of Bengal.

  1. [Macrobenthic community structure of intertidal zone of Rushan Bay in spring].

    Science.gov (United States)

    Ji, Ying-lu; Zhao, Ning; Wang, Zhen-zhong; Ji, Xiang-xing; Yang, Chuan-ping; Yu, Zi-shan

    2015-02-01

    Quantitative study on macrobenthos was carried out in 8 transects along intertidal zone of Rushan Bay in May, 2011. In total, 116 macrobenthic species were identified, among which 58 were polychaetes, 15 were mollusks, 27 were crustaceans, 3 were echinoderms and 13 were other groups. The average abundance and biomass of macrobenthos were 872.6 ind · m(-2) and 9.37 g · M(-2), respectively. By IRI index, Mediomastus sp., Helice sheni, Nemertinea and Neanthes sp. were ranked as the top 4 dominant species in the study area. Average Margalef's species richness diversity (d), Shannon diversity (H) and Pielou's evenness index (J) of macrobenthos were 2.119, 2.384 and 0.608, respectively, indicating slight pollution in the study area. Based on 30% similarity level, 8 transects could be grouped into 3 different communities. Compared with other intertidal zones in similar latitude, macrobenthos of Rushan Bay intertidal zone were characterized by higher species number, smaller body size and higher abundance. Besides the macrobenthic community structure and diversities, more exhaustive studies were needed to reveal the possible influence of shellfish culture on intertidal macrobenthic community. PMID:26094480

  2. Species composition, seasonal abundance and population structure of chaetognaths in Admiralty Bay (Antarctic

    Directory of Open Access Journals (Sweden)

    Bielecka Luiza

    2016-06-01

    Full Text Available Although chaetognaths inhabiting polar ecosystems are relatively well known, there are few reports on their functioning in the Antarctic coastal plankton community. The presented results provide the first comprehensive description of population structure of chaetognaths in the neritic zone west of the Antarctic Peninsula. The studies were performed on samples collected in Admiralty Bay, from December 1994 to June 1995. Following six chaetognath species were determined: Eukrohnia hamata, E. bathypelagica, E. fowleri, Pseudosagitta gazellae, P. maxima and Solidosagitta marri. The representatives of Eukrohnia were observed almost throughout the research period, whereas those of Pseudosagitta and Solidosagitta were found only during first four months of our investigation. Eukrohnia hamata showed a strong dominance in respect to abundance (max. 445 ind./1000 m3. The mean abundance of all taxa significantly fluctuated in the study period and across weeks. Generally, all species were represented by the first three maturity stages (I-III, individuals stage IV occurred sporadically, and mature specimens (stage V were not recorded at all. Morphometric analysis of the most abundant species showed distinct differences in their total length and body proportions. Our findings may suggest that chaetognath populations in Admiralty Bay are migrant, dependent on the inflow of water from the Bransfield Strait, but to prove this statement further, round year study is necessary.

  3. Community structure of shallow rocky shore fish in a tropical bay of the southwestern Atlantic

    Directory of Open Access Journals (Sweden)

    Camilo Moitinho Ferreira

    2015-12-01

    Full Text Available Abstract Southwestern Atlantic Ocean rocky shores sustain important reef fish communities. However, those communities in tropical regions are not well understood, especially in Brazil. In this present article we assess community parameters of reef fishes such as composition, trophic organization and their relationships with physical and biological factors on four tropical rocky shores in Todos os Santos Bay, southwestern Atlantic. During six months, a total of 80 visual censuses were performed, in which 3,582 fish belonging to 76 species were recorded. Territorial herbivorous fish and turf algae were dominant at all the sites. The spatial variability of fish community structure was related to the benthic cover composition and depth. The high abundance of territorial herbivores and mobile invertebrate feeders could be associated with high levels of turf cover, low wave exposure and shallow waters. Moreover, this fact could be a consequence of the low density of roving herbivores and large carnivores probably due to the pressure of intense fishing activity. Thus complementary studies are needed to evaluate the actual conservation status of these rocky shore reefs, singularly located habitats connecting inner and outer reefs in Todos os Santos Bay.

  4. Asgard impact structure on Callisto

    Science.gov (United States)

    1996-01-01

    This four-frame mosaic shows the ancient impact structure Asgard on Jupiter's moon Callisto. This image is centered at 30 degrees north, 142 degrees west. The Asgard structure is approximately 1700 km across (1,056 mi) and consists of a bright central zone surrounded by discontinuous rings. The rings are tectonic features with scarps near the central zone and troughs at the outer margin. Several large impacts have smashed into Callisto after the formation of Asgard. The very young, bright-rayed crater Burr is located on the northern part of Asgard. This mosaic has been projected to show a uniform scale between the four mosaiced images. The image was processed by Deutsche Forschungsanstalt fuer Luftund Raumfahrt e.V., Berlin, Germany.This image was taken on November 4, 1996, at a distance of 111,891 kilometers (69,070 miles) by the solid state imaging television camera onboard the Galileo spacecraft during its third orbit around Jupiter.The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C.This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo

  5. The unnatural history of Kāne‘ohe Bay: coral reef resilience in the face of centuries of anthropogenic impacts

    Directory of Open Access Journals (Sweden)

    Keisha D. Bahr

    2015-05-01

    Full Text Available Kāneʻohe Bay, which is located on the on the NE coast of Oʻahu, Hawaiʻi, represents one of the most intensively studied estuarine coral reef ecosystems in the world. Despite a long history of anthropogenic disturbance, from early settlement to post European contact, the coral reef ecosystem of Kāneʻohe Bay appears to be in better condition in comparison to other reefs around the world. The island of Moku o Loʻe (Coconut Island in the southern region of the bay became home to the Hawaiʻi Institute of Marine Biology in 1947, where researchers have since documented the various aspects of the unique physical, chemical, and biological features of this coral reef ecosystem. The first human contact by voyaging Polynesians occurred at least 700 years ago. By A.D. 1250 Polynesians voyagers had settled inhabitable islands in the region which led to development of an intensive agricultural, fish pond and ocean resource system that supported a large human population. Anthropogenic disturbance initially involved clearing of land for agriculture, intentional or accidental introduction of alien species, modification of streams to supply water for taro culture, and construction of massive shoreline fish pond enclosures and extensive terraces in the valleys that were used for taro culture. The arrival by the first Europeans in 1778 led to further introductions of plants and animals that radically changed the landscape. Subsequent development of a plantation agricultural system led to increased human immigration, population growth and an end to traditional land and water management practices. The reefs were devastated by extensive dredge and fill operations as well as rapid growth of human population, which led to extensive urbanization of the watershed. By the 1960’s the bay was severely impacted by increased sewage discharge along with increased sedimentation due to improper grading practices and stream channelization, resulting in extensive loss of

  6. The unnatural history of Kāne'ohe Bay: coral reef resilience in the face of centuries of anthropogenic impacts.

    Science.gov (United States)

    Bahr, Keisha D; Jokiel, Paul L; Toonen, Robert J

    2015-01-01

    Kāne'ohe Bay, which is located on the on the NE coast of O'ahu, Hawai'i, represents one of the most intensively studied estuarine coral reef ecosystems in the world. Despite a long history of anthropogenic disturbance, from early settlement to post European contact, the coral reef ecosystem of Kāne'ohe Bay appears to be in better condition in comparison to other reefs around the world. The island of Moku o Lo'e (Coconut Island) in the southern region of the bay became home to the Hawai'i Institute of Marine Biology in 1947, where researchers have since documented the various aspects of the unique physical, chemical, and biological features of this coral reef ecosystem. The first human contact by voyaging Polynesians occurred at least 700 years ago. By A.D. 1250 Polynesians voyagers had settled inhabitable islands in the region which led to development of an intensive agricultural, fish pond and ocean resource system that supported a large human population. Anthropogenic disturbance initially involved clearing of land for agriculture, intentional or accidental introduction of alien species, modification of streams to supply water for taro culture, and construction of massive shoreline fish pond enclosures and extensive terraces in the valleys that were used for taro culture. The arrival by the first Europeans in 1778 led to further introductions of plants and animals that radically changed the landscape. Subsequent development of a plantation agricultural system led to increased human immigration, population growth and an end to traditional land and water management practices. The reefs were devastated by extensive dredge and fill operations as well as rapid growth of human population, which led to extensive urbanization of the watershed. By the 1960's the bay was severely impacted by increased sewage discharge along with increased sedimentation due to improper grading practices and stream channelization, resulting in extensive loss of coral cover. The reefs of K

  7. Population structure and maturity stages of Fritillaria borealis (Appendicularia, Tunicata): seasonal cycle in Ushuaia Bay (Beagle Channel)

    OpenAIRE

    María Laura Presta; Mónica Susana Hoffmeyer; Fabiana Lia Capitanio

    2015-01-01

    AbstractFritillaria borealis is a cosmopolitan species, very frequent in sub-antarctic and antarctic waters. The objective of this paper was to analyze its size structure and maturity stages at two sites in Ushuaia Bay: a coastal site exposed to anthropogenic pressure (E1) and a reference site (E2) located in the external zone of the bay. Zooplankton was collected during the 2012 seasonal cycle. The sampling method involved the use of a 67 µm-mesh net. Appendicularians were classified in four...

  8. Effects of green macroalgal blooms on the meiofauna community structure in the Bay of Cádiz

    DEFF Research Database (Denmark)

    Bohorquez, Julio; Papaspyrou, Sokratis; Yufera, M;

    2013-01-01

    The effect of macroalgal blooms on the abundance and community structure of intertidal sediment meiofauna was studied using an in situ enclosure experiments (Bay of Cádiz, Spain). Meiofaunal abundance (3500–41,000 ind 10 cm−2) was three to sevenfold higher in the presence of macroalgae. Nematoda ...

  9. Group structure of Guiana dolphins, Sotalia guianensis (Cetacea, Delphinidae in Ilha Grande Bay, Rio de Janeiro, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigo Tardin

    2013-04-01

    Full Text Available Cetaceans present a group structure of great complexity and display a wide behavioral plasticity. Many efforts have been made to understand the group structures of the various species, however, this type of information is still lacking for some species. Therefore, our objectives were to 1 characterize the structure of the Sotalia guianensis groups in Ilha Grande Bay, Rio de Janeiro, Brazil, and 2 investigate how both behavior and season influence the group structure of this population. This species is considered "data deficient" by the IUCN. We conducted 28 boat trips using group focal procedures, and a total of 1,314 groups were observed. Of these groups, 1,268 (94.4% contained calves, the largest percentage ever reported for the species. Groups with calves were larger than those without them, suggesting a strategy to protect these individuals with underdeveloped physiology. The mean group sizes reached 17.6 ± 18.3 individuals. Within these groups, we observed that both behavior (H = 112.5, d.f. = 2, P < 0.05 and season (number of simulations: 10,000; sample size of fall-winter = 544; sample size of spring-summer = 684; P < 0.05, demonstrated a statistically significant influence. The most common degree of cohesion was mixed, and cohesion also varied with behavior (χ2 = 10.1, P < 0.05 and season (χ2 = 31.0, P < 0.05. This paper contributes towards understanding the highly variable nature of S. guianensis group dynamics. These data may be important in understanding the structure of groups in a site that is being increasingly impacted by different human activities. Moreover, this area contains the largest aggregation ever observed for this species and may therefore represent an important source of genetic diversity for the species as a whole.

  10. An Approach to Understanding Complex Socio-Economic Impacts and Responses to Climate Disruption in the Chesapeake Bay Region

    Science.gov (United States)

    Schaefer, R. K.; Nix, M.; Ihde, A. G.; Paxton, L. J.; Weiss, M.; Simpkins, S.; Fountain, G. H.; APl GAIA Team

    2011-12-01

    In this paper we describe the application of a proven methodology for modeling the complex social and economic interactions of a system under stress to the regional issues that are tied to global climate disruption. Under the auspices of the GAIA project (http://gaia.jhuapl.edu), we have investigated simulating the complex interplay between climate, politics, society, industry, and the environment in the Chesapeake Bay Watershed and associated geographic areas of Maryland, Virginia, and Pennsylvania. This Chesapeake Bay simulation draws on interrelated geophysical and climate models to support decision-making analysis about the Bay. In addition to physical models, however, human activity is also incorporated via input and output calculations. For example, policy implications are modeled in relation to business activities surrounding fishing, farming, industry and manufacturing, land development, and tourism. This approach fosters collaboration among subject matter experts to advance a more complete understanding of the regional impacts of climate change. Simulated interactive competition, in which teams of experts are assigned conflicting objectives in a controlled environment, allow for subject exploration which avoids trivial solutions that neglect the possible responses of affected parties. Results include improved planning, the anticipation of areas of conflict or high risk, and the increased likelihood of developing mutually acceptable solutions.

  11. Impact of horizontal resolution on prediction of tropical cyclones over Bay of Bengal using a regional weather prediction model

    Indian Academy of Sciences (India)

    M Mandal; U C Mohanty; K V J Potty; A Sarkar

    2003-03-01

    The present study is carried out to examine the performance of a regional atmospheric model in forecasting tropical cyclones over the Bay of Bengal and its sensitivity to horizontal resolution. Two cyclones, which formed over the Bay of Bengal during the years 1995 and 1997, are simulated using a regional weather prediction model with two horizontal resolutions of 165km and 55 km. The model is found to perform reasonably well towards simulation of the storms. The structure, intensity and track of the cyclones are found to be better simulated by finer resolution of the model as compared to the coarse resolution. Rainfall amount and its distribution are also found to be sensitive to the model horizontal resolution. Other important fields, viz., vertical velocity, horizontal divergence and horizontal moisture flux are also found to be sensitive to model horizontal resolution and are better simulated by the model with finer horizontal grids.

  12. Community Structure of Seagrass in Awerange and Labuange Bays Barru Regency South Sulawesi

    OpenAIRE

    Sarinita, Sayuri; Priosambodo, Dody

    2006-01-01

    Awerange and Labuange Bays in Barru Regency, South Sulawesi consist of various types of habitats. Mangroves, coral reef and seagrass beds can be found in these bays forming unique ecosystems. However, information about the ecosystems particularly related to seagrass community are poorly known. The aim of this research was to investigate the composition of seagrass species both in Awerange and Labuange Bays. Line transect method combined with plot were used to collect data of seagrass commu...

  13. Regional scenarios of sea level rise and impacts on Basque (Bay of Biscay) coastal habitats, throughout the 21st century

    OpenAIRE

    Chust, Guillem; Caballero, Ainhoa; Marcos, Marta; Liria, Pedro; Hernández, Carlos A.; Borja, Ángel

    2010-01-01

    Global climate models have predicted a rise on mean sea level of between 0.18 m and 0.59 m by the end of the 21st Century, with high regional variability. The objectives of this study are to estimate sea level changes in the Bay of Biscay during this century, and to assess the impacts of any change on Basque coastal habitats and infrastructures. Hence, ocean temperature projections for three climate scenarios, provided by several atmosphere-ocean coupled general climate models, have been extr...

  14. Spatial distribution of organic and pyritic sulfur in surface sediments of eutrophic Jiaozhou Bay, China: clues to anthropogenic impacts.

    Science.gov (United States)

    Chen, Ke-Ke; Zhu, Mao-Xu; Yang, Gui-Peng; Fan, De-Jiang; Huang, Xiang-Li

    2014-11-15

    Anthropogenic perturbations exert important impacts on sulfur geochemistry in marine sediments. In the study, chemical extraction was used to quantify four sulfur pools, i.e., pyrite, humic-acid sulfur (HA-S), fulvic-acid sulfur (FA-S), and residual organic sulfur (ROS), in surface sediments of eutrophic Jiaozhou Bay. Results show that riverine inputs are the main control on organic matter (OM) distribution in the sediments. OM enrichment in the eastern coast is mainly due to discharges of anthropogenic wastes. Spatial coupling of pyrite and FA-S vs. TOC points to the impacts of OM enrichment on formation and preservation of pyrite and FA-S. Poor spatial coupling of HA-S vs. TOC is due to low fractions of diagenetic OS in the pool. ROS is mainly from riverine inputs and anthropogenic OS has been superimposed on this pool. Spatial coupling among TOC, pyrite-S and FA-S is a sensitive indicator of anthropogenic impacts on benthic processes of the bay. PMID:25220315

  15. Phytoplankton community structure and environmental parameters in aquaculture areas of Daya Bay, South China Sea.

    Science.gov (United States)

    Wang, Zhaohui; Zhao, Jiangang; Zhang, Yujuan; Cao, Yu

    2009-01-01

    Environmental characteristics and phytoplankton community structure were investigated in two aquaculture areas in Dapeng Cove of Daya Bay, South China Sea, between April 2005 and June 2006. Phytoplankton abundance ranged between 5.0 and 8877.5 cells/mL, with an average of 751.8 cells/mL. The seasonal cycle of phytoplankton were demonstrated by frequent oscillations, with recurrent high abundances from late spring to autumn and a peak stage in late winter. Diatoms were the predominant phytoplankton group, accounting for 93.21% of the total abundance. The next most abundant group was the dinoflagellates, which made up only 1.24% of total abundance. High concentrations of Alexandrium tamarense (Lebour) Balech with a maximum of 603.0 cells/mL were firstly recorded in this area known for high rates of paralytic shellfish poisoning (PSP) contamination. Temperatures and salinities were within the suitable values for the growth of phytoplankton, and were important in phytoplankton seasonal fluctuations. The operation of the Daya Bay Nuclear Power Station (DNPS) exerts influences on the phytoplankton community and resulted in the high abundances of toxic dinoflagellate species during the winter months. Dissolved inorganic nitrogen (DIN) and dissolved silicate (DSi) were sufficient, and rarely limited for the growth of phytoplankton. Dissolved inorganic phosphorus (DIP) was the most necessary element for phytoplankton growth. The enriched environments accelerated the growth of small diatoms, and made for the shift in predominant species from large diatom Rhizosolenia spp. to chain-forming diatoms such as Skeletonema costatum, Pseudo-nitzschia spp. and Thalassiosira subtilis. PMID:19999976

  16. Modeling fates and impacts for bio-economic analysis of hypothetical oil spill scenarios in San Francisco Bay

    International Nuclear Information System (INIS)

    The oil spill risks associated with four submerged rock pinnacles near Alcatraz Island in San Francisco Bay are being evaluated by the United States Army Corps of Engineers. Oil spill modeling has been conducted for a hypothetical oil spill to determine biological impacts, damages to natural resources and response costs. The scenarios are hypothetical vessel grounding on the pinnacles. The SIMAP modeling software by the Applied Science Associates was used to model 3 spill sizes (20, 50 and 95 percentile by volume) and 4 types of oil (gasoline, diesel, heavy fuel oil, and crude oil). The frequency distribution of oil fates and impacts was determined by first running each scenario in stochastic mode. The oil fates and biological effects of the spills were the focus of this paper. It was shown that diesel and crude oil spills would have greater impacts in the water column than heavy fuel or gasoline because gasoline is more volatile and less toxic and because heavy oil spills would be small in volume. It was determined that the major impacts and damage to birds would be low due to the high dilution potential of the bay. It was also noted that dispersants would be very effective in reducing impacts on wildlife and the shoreline. These results are being used to evaluate the cost-benefit analysis of removing the rocks versus the risk of an oil spill. The work demonstrates a statistically quantifiable method to estimate potential impacts that could be used in ecological risk assessment and cost-benefit analysis. 15 refs., 13 tabs., 11 figs

  17. Modeling fates and impacts for bio-economic analysis of hypothetical oil spill scenarios in San Francisco Bay

    Energy Technology Data Exchange (ETDEWEB)

    French McCay, D.; Whittier, N.; Sankaranarayanan, S.; Jennings, J. [Applied Science Associates Inc., Narragansett, RI (United States); Etkin, D.S. [Environmental Research Consulting, Winchester, MA (United States)

    2002-07-01

    The oil spill risks associated with four submerged rock pinnacles near Alcatraz Island in San Francisco Bay are being evaluated by the United States Army Corps of Engineers. Oil spill modeling has been conducted for a hypothetical oil spill to determine biological impacts, damages to natural resources and response costs. The scenarios are hypothetical vessel grounding on the pinnacles. The SIMAP modeling software by the Applied Science Associates was used to model 3 spill sizes (20, 50 and 95 percentile by volume) and 4 types of oil (gasoline, diesel, heavy fuel oil, and crude oil). The frequency distribution of oil fates and impacts was determined by first running each scenario in stochastic mode. The oil fates and biological effects of the spills were the focus of this paper. It was shown that diesel and crude oil spills would have greater impacts in the water column than heavy fuel or gasoline because gasoline is more volatile and less toxic and because heavy oil spills would be small in volume. It was determined that the major impacts and damage to birds would be low due to the high dilution potential of the bay. It was also noted that dispersants would be very effective in reducing impacts on wildlife and the shoreline. These results are being used to evaluate the cost-benefit analysis of removing the rocks versus the risk of an oil spill. The work demonstrates a statistically quantifiable method to estimate potential impacts that could be used in ecological risk assessment and cost-benefit analysis. 15 refs., 13 tabs., 11 figs.

  18. ENVIRONMENTAL IMPACTS IN THE PROCESS OF SOCIAL OWNERSHIP OF SPACE IN THE BAY OF THE PONTAL IN MUNICIPALITY OF ILHÉUS / BA

    Directory of Open Access Journals (Sweden)

    Emilson Batista da Silva

    2014-07-01

    Full Text Available This study is about the relationship between society and nature, considering the impact of the appropriation of space in the estuary of Pontal Bay -Ilhéus/BA. The time frame adopted begins with the 70s and extends until the year 2012. The research approach was qualitative, adopting quantitative techniques when necessary. The instruments of collection consisted of systematic observation and interview, plus documentary and bibliographic research. The analyzes showed evidence that the socio-spatial interventions in the Bay originate from the construction of the Port of Ilheus in the northern portion, from the growing, environmental degradation of river basins tributaries (rivers Cachoeira, Santana and Itacanoeira and from the process of occupation surrounding the Bay. These pressures have caused changes in the dynamics of estuarine circulation, leading to a state of beach progradation, intensifying the process of silting up of the Bay, propension to formation of mangroves and impaired water quality due to discharge of sewage.

  19. Community structure and coral status across reef fishing intensity gradients in Palk Bay reef, southeast coast of India.

    Science.gov (United States)

    Manikandan, B; Ravindran, J; Shrinivaasu, S; Marimuthu, N; Paramasivam, K

    2014-10-01

    Coral reef fishes are exploited without the knowledge of their sustainability and their possible effect in altering the community structure of a coral reef ecosystem. Alteration of the community structure could cause a decline in the health of coral reefs and its services. We documented the coral community structure, status of live corals and reef fish assemblages in Palk Bay at the reef fishing hotspots and its nearby reef area with minimum fishing pressure and compared it with a control reef area where reef fishing was banned for more than two decades. The comparison was based on the percent cover of different forms of live corals, their diversity and the density and diversity of reef fishes. The reef fish stock in the reef fishing hotspots and its neighbouring reef was lower by 61 and 38%, respectively compared to the control reef. The herbivore fish Scarus ghobban and Siganus javus were exploited at a rate of 250 and 105 kg month(-1) fishermen(-1), respectively, relatively high comparing the small reef area. Live and dead corals colonized by turf algae were predominant in both the reef fishing hotspots and its nearby coral ecosystems. The percent cover of healthy live corals and live corals colonized by turf algae was 80%, respectively, in the intensively fished coral ecosystems. The corals were less diverse and the massive Porites and Favia colonies were abundant in the intensive reef fishing sites. Results of this study suggest that the impact of reef fish exploitation was not solely restricted to the intensively fished reefs, but also to the nearby reefs which play a critical role in the resilience of degraded reef ecosystems. PMID:24859909

  20. Social representations about the environmental impact of thermal companies in the bay of Quintero-Puchuncaví

    Directory of Open Access Journals (Sweden)

    Claudia Carrasco Aguilar

    2015-07-01

    Full Text Available In the Bay of Quintero-Puchuncaví there is a tension between economic development, preservation of natural resources and quality of life. This research presents a qualitative study that aimed to answer the question: Which social representations do the residents of the Bay of Quintero-Puchuncaví have about the environmental impact in the area? In order to attempt this, two focus groups were performed. The first one was composed by school employees and the second one by members of the movement “Communities for the Right to Life”. Subsequently a content analysis was developed. This yielded as a main result that the Social Representation of these groups would be oriented by their own common sense, assuming as a part of it that in the area would prevail industrial economic development to the detriment of natural resources, health, quality of life and human rights of the inhabitants of the sector. It was also detected in these groups, the idea of an existing policy to conceal information from them, as well as welfarist measures that try ineffectively to mitigate the damage caused. Thus, it is recognized an unfavorable attitude in both groups to the environmental impact generated by industries, believing that this issue has exceeded all the limits. This mobilizes toward micro level actions in the case of teachers and local level actions in the case of the Movement.

  1. The effects of climate variability on the structure of the phytoplankton community in Tumaco Bay, Colombia

    Science.gov (United States)

    Honkala, Ingrid Garcia-Hansen

    2009-12-01

    Spatiotemporal variability in the diatom and dinoflagellate community structure and chlorophyll a (chl a) concentrations in Tumaco Bay during the 1993--2005 period was related clearly to seasonal and interannual variability in environmental conditions due to the migration of the Inter-tropical Convergence Zone (ITCZ) and the influence of El Nino Southern Oscillation (ENSO) events. A total of 134 species of diatoms that belong to 57 genera, and 78 species of dinoflagellates that belong to 25 genera were identified during the survey. The diatom community was the dominant group in the waters of the bay, being the most abundant with the greatest number of species observed. The most important species was the centric diatom Skeletonema costatum (Cleve 1878). It was found that the migration of the ITCZ on the region caused a strong annual cycle. With the migration of the ITCZ to the south, Northeasterly Trade Winds dominated the area from about December to April producing oceanic and coastal upwelling. Colder sea surface temperatures (SST), the rising of the thermocline and halocline to the surface, increased nutrients and abundant rainfall were detected. This time of the year was described as the rainy season (RS)/cold phase. Opposite conditions were observed the rest of the year, defined as the dry season (DS)/warm phase. Southeasterly Trade Winds dominated at this time of the year due to the migration of the ITCZ back to the north. This seasonal cycle was affected by interannual variability due to ENSO. Five El Nino and four La Nina events were identified. In general, La Nina episodes were characterized by a shallow thermocline, cold SST, higher salinities, and the highest concentrations of nutrients. Opposite characteristics were observed during El Nino events. However, during the highest precipitations observed in every El Nino event, nutrient concentrations increased significantly. Important environmental correlates of community structure were identified using

  2. Structural Interpretation of the Qingdong Area in Bohai Bay Basin from Shipborne Gravity Data

    Directory of Open Access Journals (Sweden)

    Zhang Chunguan

    2015-09-01

    Full Text Available The Qingdong area, located in Bohai bay basin, was suspected good exploration prospects. In order to study tectonic features and find out favourable petroleum prospects in the area, the gravity data at a scale of 1:50,000 were interpreted. This paper, through data processing and synthetic interpretation of the high-precision gravity data in the area, discusses characteristics of the gravity field and their geological implications, determines the fault system, analyses features of the main strata, divides structure units and predicts favourable petroleum zones. The results showed that the faults controlled the development of the Mesozoic and Cenozoic strata and the distribution of local structures in this area. The study revealed that the Qingtuozi uplift and the Kendong uplift in the north were formed in Mesozoic, and the Qingdong depression in the middle was the rift basin in Mesozoic and Cenozoic. Thicker strata in Mesozoic and Cenozoic developed in the Dongying depression and the Qingdong depression, so there is abundant hydrocarbon in these two depressions, and then the Guangligang rise-in-sag and the Qingdong rise-in-sag developed in the center in these two depressions are also favorable places for prospecting

  3. Inner Structure of Atmospheric Inversion Layers over Haifa Bay in the Eastern Mediterranean

    Science.gov (United States)

    Haikin, N.; Galanti, E.; Reisin, T. G.; Mahrer, Y.; Alpert, P.

    2015-09-01

    Capping inversions act as barriers to the vertical diffusion of pollutants, occasionally leading to significant low-level air pollution episodes in the lower troposphere. Here, we conducted two summer campaigns where global positioning system radiosondes were operated in Haifa Bay on the eastern Mediterranean coast, a region of steep terrain with significant pollution. The campaigns provided unique high resolution measurements related to capping inversions. It was found that the classical definition of a capping inversion was insufficient for an explicit identification of a layer; hence additional criteria are required for a complete spatial analysis of inversion evolution. Based on the vertical temperature derivative, an inner fine structure of inversion layers was explored, and was then used to track inversion layers spatially and to investigate their evolution. The exploration of the inner structure of inversion layers revealed five major patterns: symmetric peak, asymmetric peak, double peak, flat peak, and the zig-zag pattern. We found that the symmetric peak is related to the strongest inversions, double peak inversions tended to break apart into two layers, and the zig-zag pattern was related to the weakest inversions. Employing this classification is suggested for assistance in following the evolution of inversion layers.

  4. Climate change impacts on vegetation in the San Francisco Bay Area: a novel approach to vulnerability analysis (Invited)

    Science.gov (United States)

    Ackerly, D.; Cornwell, W. K.; Weiss, S. B.; Branciforte, R.; Flint, L. E.; Flint, A. L.

    2010-12-01

    Climate change is expected to profoundly impact terrestrial vegetation. Understanding spatial variability of these impacts is critical to development of conservation strategies and projections of ecosystem services under future climates. We present a model of the projected impacts of climate change on the distribution of vegetation types in the San Francisco Bay Area using a novel application of multinomial logistic regression. The output of this method is a vector of the relative probability of occupancy by each of a set of vegetation types, for each pixel in the landscape. This approach models all vegetation types, in contrast to methods that model the distribution of each type or species individually. The overall vulnerability of vegetation to climate change can then be quantified as the change in modeled probabilities between the vectors modeled under present versus future climates. These changes capture the likelihood of long-term climate-driven vegetation change for each pixel, without relying on specific predictions of present and future vegetation types. This measure of vulnerability can be further decomposed as the product of two components, one reflecting the intrinsic sensitivity of the vegetation to climate and the second measuring the exposure to (i.e., magnitude of) climate change. Based on a new set of high-resolution downscaled climate projections for Coastal California, including an estimate of the annual climatic water deficit, we demonstrate that the vulnerability of vegetation distributions is almost entirely due to variation in sensitivity, and not to differences in the magnitude of climate change. Furthermore, there are weak but significant trends towards greater sensitivity on cool, north-facing slopes and in valley bottoms, as well as a bimodal distribution with greater sensitivity under the coolest and warmest summer temperature regimes in the Bay Area. These results do not support a commonly held conviction that cool environments will act

  5. Searching for order in chaos: a sediment stratigraphical study of a multiple-impacted bay of the Baltic Sea

    Science.gov (United States)

    Vaalgamaa, S.; Korhola, A.

    2004-02-01

    The lithological and geochemical properties of sediment cores collected from a heavily impacted embayment in the Gulf of Finland, Baltic Sea, were investigated. Hillonlahti Bay has been the focus of much human activity, including timber and oil industries, transportation, housing, dredging and waste discharge, thus constituting an exceptionally challenging environment for sediment studies. A total of nine cores were sampled along perpendicular transects across the elongated bay, and described lithologically in the field. Major and trace element concentrations were determined for a "master core" taken from the central area of the bay. The vertical distribution of 210Pb, 137Cs and spheroidal carbonaceous particles (SCP) was also examined in order to provide a chronological framework for the sediment. Changes in the sediment nature and differences in the distributions of soluble heavy metals (Cd, Cr, Cu, Ni, V, Zn), lithophilous (Al, Ti, K, Mg, Ca, Na), redox-sensitive (Fe, Mn), and nutrient (TP) elementary concentrations were related to temporal and spatial processes. These include the building of the Hamina port starting in the mid-1930s, establishment of the timber and oil industry in 1950-1960s, construction of railway embankments in 1950 and 1996, increasing urbanisation from 1960s, and wastewater discharge between 1950 and 1987. The use of Cr as a preservative in the wood processing industry is reflected in the marked enrichment of Cr in the sediment, while the influence of wastewater discharge can be seen in the sediment record by a rise in concentrations of P and evidently organically bound Na, Cu and Zn. The results are encouraging in demonstrating that via a rather simple repertoire of sediment-analytical methods it is possible to obtain information about the land-use history and contamination in such a strongly rampaged system.

  6. Edge impact modeling on stiffened composite structures

    OpenAIRE

    Ostré, Benjamin; Bouvet, Christophe; Minot, Clément; Aboissière, Jacky

    2015-01-01

    Finite Element Analysis of low velocity/low energy edge impact has been carried out on carbon fiber reinforced plastic structure. Edge impact experimental results were then compared to the numerical ‘‘Discrete Ply Model’’ in order to simulate the edge impact damage. This edge impact model is inspired to out-of-plan impact model on a laminate plate with addition of new friction and crushing behaviors. From a qualitative and quantitative point of view, this edge impact model reveals a relati...

  7. Assessing the impact of aquaculture farms using remote sensing: an empirical neural network algorithm for Ildırı Bay, Turkey

    OpenAIRE

    Bengil, Fethi; Bizsel, K. Can

    2014-01-01

    Abstract The potential impact of aquaculture on Ildırı Bay, Turkey, was assessed using remote sensing data collected over 37 d between September 2009 and February 2011. The dataset was improved by applying a local empirical neural network (NN) algorithm. Impact was evaluated in terms of total suspended matter (TSM) and Secchi disk depth (SDD) as effective variables showing changes in underwater light fields in each defined subarea. Subareas were farm sites with their peripheries (impact z...

  8. Soft impacts on aerospace structures

    Science.gov (United States)

    Abrate, Serge

    2016-02-01

    This article provides an overview of the literature dealing with three types of soft impacts of concern for the aerospace applications, namely impacts of rain drops, hailstones and birds against aircraft. It describes the physics of the problem as it has become better understood through experiments, analyses, and numerical simulations. Some emphasis has been placed on the material models and the numerical approaches used in modeling these three types of projectiles.

  9. Human and riverine impacts on the dynamics of biogeochemical parameters in Kwangyang Bay, South Korea revealed by time-series data and multivariate statistics.

    Science.gov (United States)

    Kim, Tae-Wook; Kim, Dongseon; Baek, Seung Ho; Kim, Young Ok

    2015-01-15

    The successful management of sustainable coastal environments that are beneficial to both humans and marine ecosystems requires knowledge about factors that are harmful to such environments. Here, we investigated seawater nutrient and carbon parameters between 2010 and 2012 in Kwangyang Bay, Korea, a coastal environment that has been exposed to intensive anthropogenic activities. The data were analyzed using cluster and factor analysis. We found that the biogeochemical cycles of nutrients and carbon were determined by river discharge into the bay and biological activity. However, the impacts of these factors varied both spatially and seasonally. During the past 10 years, nutrient loads from the river and industrial complexes to the bay have decreased. The impacts of this decrease are visible in the phosphate concentration, which has fallen to a third of its initial value. We also examined the potential role of atmospheric nitrogen deposition in nitrogen cycling in the study area. PMID:25481735

  10. Current structure and volume transport across 12 degrees N in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Murty, V.S.N.; Suryanarayana, A.; Rao, D.P.

    Geostrophic currents and the associated volume transport across 12 degrees N in the Bay of Bengal during early southwest monsoon (April), southwest monsoon (September) and early northeast monsoon (November) show flow reversal near the east coast...

  11. Bayes Clustering and Structural Support Vector Machines for Segmentation of Carotid Artery Plaques in Multicontrast MRI

    OpenAIRE

    Qiu Guan; Bin Du; Zhongzhao Teng; Jonathan Gillard; Shengyong Chen

    2012-01-01

    Accurate segmentation of carotid artery plaque in MR images is not only a key part but also an essential step for in vivo plaque analysis. Due to the indistinct MR images, it is very difficult to implement the automatic segmentation. Two kinds of classification models, that is, Bayes clustering and SSVM, are introduced in this paper to segment the internal lumen wall of carotid artery. The comparative experimental results show the segmentation performance of SSVM is better than Bayes.

  12. Social structure and underwater behavior of harbor seals in southern Monterey Bay, California

    OpenAIRE

    Nicholson, Teri Elizabeth

    2000-01-01

    To understand harbor seal social and mating strategies, I examined site fidelity, seasonal abundance and distribution, herd integrity, and underwater behavior of individual harbor seals in southern Monterey Bay. Individual harbor seals (n = 444) were identified by natural markings and represented greater than 80% of an estimated 520 seals within this community. Year to year fidelity of individual harbor seals to southern Monterey Bay coastline was 84% (n = 388), and long-term association...

  13. Polychaete assemblage of an impacted estuary, Guanabara Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Leonardo Santi

    2009-12-01

    Full Text Available Thirty-eight stations were sampled in Guanabara Bay, Rio de Janeiro, Brazil, to assess the spatio-temporal diversity and biomass of sublittoral polychaetes. Samples were collected during the dry (September 2000 and rainy season (May 2001 in shallow sublittoral sediments. The polychaete spatial composition showed a heterogeneous distribution throughout the bay. A negative gradient of diversity and biomass was observed towards the inner parts of the bay and sheltered areas. A wide azoic area was found inside the bay. Some high-biomass and low-diversity spots were found near a sewage-discharge point. In these areas, the polychaete biomass increased after the rainy season. A diversified polychaete community was identified around the bay mouth, with no dramatic changes of this pattern between the two sampling periods. Deposit-feeders were dominant in the entire study area. The relative importance of carnivores and omnivores increased towards the outer sector, at stations with coarse sediment fractions. Guanabara Bay can be divided into three main zones with respect to environmental conditions and polychaete diversity and biomass patterns: A High polychaete diversity, hydrodynamically exposed areas composed of sandy, oxidized or moderately reduced sediments with normoxic conditions in the water column. B Low diversity and high biomass of deposit and suspension-feeding polychaete species in the middle part of the bay near continental inflows, comprising stations sharing similar proportions of silt, clay and fine sands. C Azoic area or an impoverished polychaete community in hydrodynamically low-energy areas of silt and clay with extremely reduced sediments, high total organic matter content and hypoxic conditions in the water column, located essentially from the mid-bay towards the north sector. High total organic matter content and hypoxic conditions combined with slow water renewal in the inner bay seemed to play a key role in the polychaete

  14. An integrated approach to the assessment of pollutant delivery chronologies to impacted areas: Hg in the Augusta Bay (Italy).

    Science.gov (United States)

    Bellucci, Luca Giorgio; Giuliani, Silvia; Romano, Stefania; Albertazzi, Sonia; Mugnai, Cristian; Frignani, Mauro

    2012-02-21

    Assessing pollution levels and trends in heavily impacted environments is important but hardly achievable due to the difficulty of recovering suitable undisturbed sediment records. An integrated approach is here presented to solve this kind of problem. It was adopted in the Augusta Bay (Italy) for the study of Hg historical inputs and present trends. Archive information on dredging and mud disposal, together with bathymetry and high-resolution seismic profiles, were used to identify suitable sampling sites. Undisturbed sediment cores were collected in the port and bay. Sediments were analyzed for depth distributions of radiotracers ((210)Pb and (137)Cs), Hg, and main sediment parameters (magnetic susceptibility, grain size, dry bulk density, mineralogy, and organic carbon and nitrogen contents). Hexachlorobenzene (HCB) was also analyzed as an additional time tracer, since its production history in the area was well-known. Results show that peak Hg contamination (up to 575 mg·kg(-1)) was reached in the 1970s. Technological improvements and waste treatment in the following years determined a consistent decrease, but high concentrations still affect surficial sediments (0.25-92 mg·kg(-1)). Hg-HCB correlation suggests that this situation is likely the effect of resuspension and redistribution of deep sediments by dredging and naval traffic. PMID:22233219

  15. Structural and functional characteristics of avicennia germinans mangrove formation of Chengue bay (Colombian Caribbean)

    International Nuclear Information System (INIS)

    Within the framework of the CARICOMP (Caribbean coastal marine productivity) monitoring program, a study of the avicennia germinans mangrove formation of Chengue bay (Tayrona natural park, Colombia) was performed between June 1995 and July 1996, based on the evaluation of structural and functional characteristics at three monitoring plots (10 x 10 m). The structure of the studied formation is coincident with that of fringing forests of the Caribbean region in having small trees (dbh=11.3 cm, total height=6.3 m) and high densities (16.3 trunks/0.01 ha). During the monitored period there was a low mortality rate (0.7 trees/year) and there were significant increases of the circumferences at breast height (as well as of the variables derived from this measure) average tree growth rates expressed in height, dbh and basal area were 26.7 cm/year, 0.17 cm/year and 2.9 cm/year respectively. Litterfall was composed principally by leaves (66.1%) and represented a mean production rate of 43.1 g/m2/month (5.2 t/ha/year). there was a temporal pattern of litterfall production associated with the climatic seasons in the area: during rainy months the production of total litterfall, leaves and fruits was higher, while during the dry season there was a reduction of these components and an increase of flowers and wood/twigs. therefore, flowering and fruit production periods are fitted to an annual reproductive cycle. In general, the information gathered during this study is a new contribution to the knowledge of mangrove ecology in Chengue and showed that the monitored trees had the conditions to grow and develop during the evaluated period

  16. The recognition of terrestrial impact structures

    Directory of Open Access Journals (Sweden)

    Therriault A M

    2002-12-01

    Full Text Available The Earth is the most endogenically active of the terrestrial planets and, thus, has retained the poorest sample of impacts that have occurred throughout geological time. The current known sample consists of approximately 160 impact structures or crater fields. Approximately 30% of known impact structures are buried and were initially detected as geophysical anomalies and subsequently drilled to provide geologic samples. The recognition of terrestrial impact structures may, or may not, come from the discovery of an anomalous quasi-circular topographic, geologic or geophysical feature. In the geologically active terrestrial environment, anomalous quasi-circular features, however, do not automatically equate with an impact origin. Specific samples must be acquired and the occurrence of shock metamorphism, or, in the case of small craters, meteoritic fragments, must be demonstrated before an impact origin can be confirmed. Shock metamorphism is defined by a progressive destruction of the original rock and mineral structure with increasing shock pressure. Peak shock pressures and temperatures produced by an impact event may reach several hundreds of gigaPascals and several thousand degrees Kelvin, which are far outside the range of endogenic metamorphism. In addition, the application of shockwave pressures is both sudden and brief. Shock metamorphic effects result from high strain rates, well above the rates of normal tectonic processes. The well-characterized and documented shock effects in quartz are unequivocal indicators and are the most frequently used indicator for terrestrial impact structures and lithologies.

  17. Trace/heavy metal pollution monitoring in estuary and coastal area of Bay of Bengal, Bangladesh and implicated impacts.

    Science.gov (United States)

    Kibria, Golam; Hossain, Md Maruf; Mallick, Debbrota; Lau, T C; Wu, Rudolf

    2016-04-15

    Using artificial mussels (AMs), this study reports and compares time-integrated level of eleven trace metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, U, Zn) in Karnafuli River estuary and coastal area of the Bay of Bengal, Bangladesh. Through this study, "hot spots" of metal pollution were identified. The results may demonstrate that the Karnafuli Estuary, and adjacent coastal area of Chittagong, Bangladesh are highly polluted by high risk metals (cadmium, chromium, copper, mercury, nickel, lead, uranium). Agricultural, domestic and industrial wastes directly discharged into the waterways have been identified as the main causes of metal pollution in Chittagong, Bangladesh. The high level of metal pollution identified may impact on local water quality, and seafood catch, livelihoods of people and public health resulting from seafood consumption. There is a need for regular monitoring to ascertain that local water quality with respect to metal levels are within acceptable levels to safeguards both environmental health and public health. PMID:26917093

  18. Impact of Late Holocene climate variability and anthropogenic activities on Biscayne Bay (Florida, U.S.A.): evidence from diatoms

    Science.gov (United States)

    Wachnicka, Anna; Gaiser, Evelyn; Wingard, Lynn; Briceño, Henry; Harlem, Peter

    2013-01-01

    Shallow marine ecosystems are experiencing significant environmental alterations as a result of changing climate and increasing human activities along coasts. Intensive urbanization of the southeast Florida coast and intensification of climate change over the last few centuries changed the character of coastal ecosystems in the semi-enclosed Biscayne Bay, Florida. In order to develop management policies for the Bay, it is vital to obtain reliable scientific evidence of past ecological conditions. The long-term records of subfossil diatoms obtained from No Name Bank and Featherbed Bank in the Central Biscayne Bay, and from the Card Sound Bank in the neighboring Card Sound, were used to study the magnitude of the environmental change caused by climate variability and water management over the last ~ 600 yr. Analyses of these records revealed that the major shifts in the diatom assemblage structures at No Name Bank occurred in 1956, at Featherbed Bank in 1966, and at Card Sound Bank in 1957. Smaller magnitude shifts were also recorded at Featherbed Bank in 1893, 1942, 1974 and 1983. Most of these changes coincided with severe drought periods that developed during the cold phases of El Niño Southern Oscillation (ENSO), Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), or when AMO was in warm phase and PDO was in the cold phase. Only the 1983 change coincided with an unusually wet period that developed during the warm phases of ENSO and PDO. Quantitative reconstructions of salinity using the weighted averaging partial least squares (WA-PLS) diatom-based salinity model revealed a gradual increase in salinity at the three coring locations over the last ~ 600 yr, which was primarily caused by continuously rising sea level and in the last several decades also by the reduction of the amount of freshwater inflow from the mainland. Concentration of sediment total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) increased in the

  19. Characterizing exposure and potential impacts of contaminants on seabirds nesting at South San Diego Bay Unit of the San Diego National Wildlife Refuge (Salt Works, San Diego Bay)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In 2005, a two-year USFWS study (1261-1N74) was initiated to characterize contaminant exposure by seabirds that nest in colonies at the South Bay Salt Works, within...

  20. Impact loads on nuclear power plant structures

    International Nuclear Information System (INIS)

    The first step in evaluation of a NPP design for protection against impact loading, is to identify those events that may be credible for a particular site. In connection with external, man-made events IAEA Safety Series No.50-SG-S5 provides a methodology for selecting the events that need to be considered. This presentation deals with modelling of interface forces in projectile impact against unyielding structures, vibrations induced by impact, penetration, scabbing and perforation effects

  1. The impact of storms in the morphodynamic evolution of a human-impacted semi-sheltered beach (Agadir Bay, Morocco)

    Science.gov (United States)

    Aouiche, I.; Daoudi, L.; Anthony, E. J.; Sedrati, M.; Harti, A.; Ziane, E.

    2016-03-01

    This study discusses the morphological changes and evolution of Agadir Bay beach (Morocco) in response to eight storms between January 2014 and March 2014. A comparison is carried out of the evolution and variability of the beach in a sector of the bay protected by the commercial harbour of Agadir relative to a sector down drift of the harbour that is more exposed to waves, and changes affecting the beach following these storms are examined. Wave influence is evaluated using numerical simulations. The results show that despite being of relatively low intensity, the two first storm events, and especially storm 1, are responsible for major beach morphological changes. Three zones were identified as a function of the beach sediment dynamics: (i) a northern zone, representing the sector of the beach protected by Agadir harbour, with a net loss of about 21% of the total sediment, (ii) a southern zone, corresponding to the exposed sector with a net loss reaching74% of the total sediment, and (iii) a sector of residual dune that recorded no significant change during the storms.

  2. Response of masonry structure under impact load

    International Nuclear Information System (INIS)

    The paper deals with interaction of a short gaseous impact wave with a plate structure. Analyses of dynamic bending, depending on the parameters of the structure and the impact wave (i.e. the stress and displacement field produced by the resulting incident and reflected wave) have been made by FEM. The calculated data was based on the real material properties of this structure. Pressures greater than computed limit pressures result in the failure of the structure. The calculated and experimental data are compared. (author)

  3. Impact Loading of Composite and Sandwich Structures

    OpenAIRE

    Kazemahvazi, Sohrab

    2010-01-01

    Low weight is one of the most important factors in the design process of high speed naval ships, road vehicles and aircrafts. Lower structural weight enables the possibility of down-sizing the propulsion system and thus decrease manufacturing and operating costs as well as reducing the environmental impact. Two efficient ways of reducing the structural weight of a structure is by using high performance composite materials and by using geometrically efficient structures such as the sandwich co...

  4. Impact of biting midges on residential property values in Hervey Bay, Queensland, Australia.

    Science.gov (United States)

    Ratnayake, Jay; Dale, Pat E; Sipe, Neil G; Daniels, Peter

    2006-03-01

    Biting midges (Culicoides spp.) are an important environmental health issue in Hervey Bay, an area of rapid population growth in Australia. It is also the gateway to a World Heritage area (Great Sandy Strait) and a destination for tourists. The spread of housing developments into suburbs close to midge breeding habitats has led to a problem for the local government responsible for managing biting insects in its area. Suburbs with a severe biting midge problem were found to have significantly lower residential property values than less affected suburbs. The gross reduction in value in due to the midge problem was estimated to range from more than AUS dollar 25 million, based on actual sale price, to more than AUS dollar 55 million, based on the perceptions of the most severely affected residents. PMID:16646336

  5. Crustal structure of the coastal and marine San Francisco Bay region, California

    Science.gov (United States)

    Parsons, Tom, (Edited By)

    2002-01-01

    As of the time of this writing, the San Francisco Bay region is home to about 6.8 million people, ranking fifth among population centers in the United States. Most of these people live on the coastal lands along San Francisco Bay, the Sacramento River delta, and the Pacific coast. The region straddles the tectonic boundary between the Pacific and North American Plates and is crossed by several strands of the San Andreas Fault system. These faults, which are stressed by about 4 cm of relative plate motion each year, pose an obvious seismic hazard.

  6. Structure, stratigraphy, and eruption dynamics of a young tuff ring: Hanauma Bay, O'ahu, Hawai'i

    Science.gov (United States)

    Rottas, K. M.; Houghton, B. F.

    2012-09-01

    The Hanauma Bay-Koko Head complex is one of several young volcanic landforms along the Koko fissure, in southeastern O'ahu. The Hanauma Bay region of the complex comprises two nested tuff rings, inner and outer Hanauma Bay, and multiple smaller vents. The internal structure of the inner tuff ring, well exposed due to subsequent breaching by the ocean and wave erosion, indicates that it formed during a minimum of five distinct phases of deposition that produced five mappable units. Significant inward collapses generated major unconformities that separate the units exposed in the inner wall. The planes of failure are cut by narrow steep-walled, locally overhung channels and gullies, suggesting that the collapse events were each followed by short time breaks during which the deposits were eroded by rainfall runoff. Within each pyroclastic unit, there are many local slump scars and unconformities, suggesting that minor instability of the inner wall was a near-constant feature. From bedding sags and surge bed forms, it is apparent that the vent shifted at least twice during tuff ring growth. Ballistic blocks in the youngest unit indicate that the eruption overlapped in time with a separate eruption to the north, most likely to be that of the Kahauloa tuff ring 880 m away.

  7. Occurrence and distribution of antibiotics in coastal water of the Bohai Bay, China: Impacts of river discharge and aquaculture activities

    International Nuclear Information System (INIS)

    The presence of 21 antibiotics in six different groups was investigated in coastal water of the Bohai Bay. Meantime, to illuminate the potential effects caused by the river discharge and aquaculture activities, wastewater from three breeding plants and surface water from six rivers flowing into the Bohai Bay were also analyzed for the selected antibiotics. The result revealed that measured antibiotics in the North Bobai Bay were generally higher than those in the South, highlighting the remarkable effects of high density of human activities on the exposure of antibiotics in environment. The antibiotics found in the six rivers were generally higher than those in the Bohai Bay reflecting the important antibiotics source of river discharge. This study reveals that the high consumption of some antibiotics in aquaculture activities may pose high ecological risk to the bay. - Highlights: → Some antibiotics were ubiquitous with high concentration in the Bohai bay, North China. → The antibiotics were mainly from the six rivers discharge around the Bay. → Antibiotics are commonly used in aquaculture activities around the Bay. → Aquaculture was suggested to be an important antibiotics source in the Bay. - River discharge and aquaculture were suggested to be important sources for antibiotics occurred in the coastal water of the Bohai Bay, North China.

  8. Impact of Shrimp Farm Effluent on Water Quality in Coastal Areas of the World Heritage-Listed Ha Long Bay

    Directory of Open Access Journals (Sweden)

    Thuyet D. Bui

    2012-01-01

    Full Text Available Problem statement: Shrimp farming has rapidly developed in coastal areas of the World Heritage-listed Ha Long Bay since the last decade. Effluent discharged from shrimp farms with high levels of nutrient waste may cause eutrophication in receiving waterways. Therefore, assessing water quality at tidal creeks receiving shrimp farm effluent in coastal areas of Ha Long Bay supports environmental protection and decision making for sustainable development of the region. Approach: Water samples were collected at 3 different locations for spatial assessment: inside sections of creeks directly receiving farm effluent (IEC, from main creeks adjacent to points of effluent discharge outside concentrated shrimp farms (OEC and a few kilometers away from shrimp farm (ASF. Samples were taken on 3 occasions for temporal assessment. Parameters related to nutrient waste from shrimp farms, including: Total Ammonia Nitrogen (TAN, Nitrite-Nitrogen (NO2-N, Nitrate-Nitrogen (NO3-N, Total Phosphorus (TP, Dissolved Orthophosphate (PO4-P, Biochemical Oxygen Demand (BOD, Chemical Oxygen Demand (COD, Total Suspended Solid (TSS, Chlorophyll-a (Chl-a, Temperature, Salinity, pH and Dissolved Oxygen (DO were determined using standard methods. Results: There were statistically significant differences in the concentrations of TAN, NO2-N, NO3-N, TP, PO4-P, BOD, COD and Chl-a among IEC, OEC, ASF and the levels of these parameters increased after shrimp crops, especially after the main shrimp crop of the season in North Vietnam. The concentrations of TAN, NO3-N, TP, BOD, COD, Chl-a, TSS at IEC sites were higher than recommended for protecting aquatic ecosystems. Principal Component Analysis (PCA efficiently summarized patterns of co-variation in water quality parameters among locations and study times. Conclusion/Recommendations: The findings of this study indicate that greater awareness of the environmental impacts of shrimp farms is required if this industry is to be sustainable

  9. Concrete structures under impact loading rate effects

    NARCIS (Netherlands)

    Zielinski, A.J.

    1984-01-01

    Various structures may be subjected to accidental, impact loading. The behaviour of structures under that kind of extreme loading conditions is of vital importance for people's safety and environmental damage prevention. There is a need for reliable assessment methods for the local and the overal

  10. Sound speed structure in the Arabian Sea and the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Navelkar, G.S.; Murty, T.V.R.; Somayajulu, Y.K.; Murty, C.S.

    Sound speed computed from annual mean temperature and salinity data of Levitus reveals that spatial variation in the Arabian Sea is greater than that in the Bay of Bengal. Maximum spatial variation of sound speed in the Arabian Sea noticed between...

  11. EFFECTS OF DDT SEDIMENT-CONTAMINATION ON MACROFAUNAL COMMUNITY STRUCTURE AND COMPOSITION IN SAN FRANCISCO BAY

    Science.gov (United States)

    The objectives of this study were to determine the effects of sediment contamination on the benthic macrofauna and to predict macrofaunal changes following remediation at a Superfund (uncontrolled hazardous waste) site in San Francisco Bay, CA, USA. DDT and its metabolites (sumDD...

  12. Weekly Variations in Phytoplankton Structure of a Harbour in Mersin Bay (north-eastern Mediterranean)

    OpenAIRE

    EKER, Elif; KIDEYS, Ahmet Erkan

    2000-01-01

    Weekly variations in the phytoplankton composition of a harbour in Mersin Bay were studied with two methods: filtration for the assessment of >55 mm phytoplankton from July 1995 to June 1997; and sedimentation for the assessment of all phytoplankton (both>55 mm and

  13. Phenotypic impact of genomic structural variation

    DEFF Research Database (Denmark)

    Weischenfeldt, Joachim; Symmons, Orsolya; Spitz, François;

    2013-01-01

    Genomic structural variants have long been implicated in phenotypic diversity and human disease, but dissecting the mechanisms by which they exert their functional impact has proven elusive. Recently however, developments in high-throughput DNA sequencing and chromosomal engineering technology have...... delineating disease-causing elements that are affected by structural variants, and we discuss future directions for research on the functional consequences of structural variants....

  14. Active interplay between strike-slip and extensional structures in a Back-Arc environment, Bay of Plenty, New Zealand

    Science.gov (United States)

    Barnes, P. M.; Lamarche, G.; Bull, J. M.

    2003-12-01

    Active continental back-arc tectonics associated with the oblique Hikurangi subduction zone, North Island, New Zealand, is characterized by (1) extensional deformation distributed across a 40-50 km-wide zone, but presently concentrated in the east within the 20 km-wide, NE-striking Taupo Fault Belt (TFB) and Whakatane Graben (WG); (2) c. 12mm/yr extension rate at the Bay of Plenty coast; (3) 1-3 mm/yr subsidence in the WG; and (4) a seismogenic zone estimated to be 6-9 km thick. A component of the oblique convergence within the plate boundary is partitioned to the east onto the adjacent North Island Dextral Fault Belt (NIDFB), a large NNE-trending strike-slip fault system traversing the entire North Island. At the Bay of Plenty coast, the NIDFB strikes north, with an estimated strike-slip rate of at least 1 mm/yr. Both normal and strike-slip fault systems extend beneath the continental shelf in the Bay of Plenty, and because of differences in their strike, they converge and interact. Detailed mapping of faults using marine seismic reflection profiles and multibeam bathymetric data reveals the structure of the WG. Tilted basement blocks are associated with large west-dipping faults, numerous antithetic secondary faults, and domino-style fault arrays. Eastward migration of the principal extension zone during the last c. 1 Myrs has resulted in the encroachment and oblique overprinting of the NIDFB by the WG. The structure and geometry of the White Island Fault (WIF), currently the principal fault along the eastern margin of the graben, results from interaction and linkage of the two fault systems. The displacement profile of this fault reveals relatively young NE-striking sections that obliquely link more northerly-striking, inherited components of the NIDFB. Understanding of the fault structure and evolution may have implications for the interpretation of earthquake potential close to urban centres.

  15. Substrate Variations and its Relationship and Impact on the Distribution of Eelgrass Beds in Griffin Bay, Washington

    Science.gov (United States)

    Sopha, A.; Greene, H.; Wyllie-Echeverria, S.; Harmsen, F. J.

    2010-12-01

    Eelgrass is considered an important indicator species for the health of the oceans; it provides nearshore habitat to many marine organisms and also acts as a source of protection for migrating populations of juvenile salmon and other fish species including forage fish. Since the late 1980s, there has been a drastic decline in eelgrass beds within the surrounding marine areas of Washington State; specifically in the species Zostera marina. Previous studies have focused on potential impacts such as bacterial infections and loss of sunlight from docks, shoreline tree canopy overgrowth and permanently anchored boats. In specific locations, sawmill waste has prevented the regeneration of eelgrass. In this study, sediment samples, along with video transects, were collected from Griffin Bay, Washington, located within the San Juan Archipelago to determine if substrate conditions have any impact on the distribution, appearance, disappearance, and health of the eelgrass beds. Initial findings indicate that in fact, eelgrass is increasing with growth beyond the area in which their distribution was previously documented. This is in contrast to other areas where eelgrass is in decline. Final results have yet to be analyzed.

  16. Down-core changes in molluscan death assemblages at Panzano Bay, an impacted area in the northern Adriatic Sea

    Science.gov (United States)

    Haselmair, Alexandra; Gallmetzer, Ivo; Stachowitsch, Michael; Tomasovych, Adam; Zuschin, Martin

    2016-04-01

    We use a historical ecology approach to shed light on the environmental history of the northern Adriatic Sea over the last hundreds to thousands of years. We focus on down-core changes in molluscan death assemblages, which serve as proxies for ecological shifts over time. The northern Adriatic Sea is particularly suited to study ecosystem modification under human pressure because it is among the most degraded marine ecosystems worldwide. We chose a sampling station in Panzano Bay, close the Isonzo River mouth and not far from the major industrial harbours of Trieste (Italy) and Koper (Slovenia), and traced down-core changes in molluscan community structure in correlation to major anthropogenic impacts that occurred here during the last centuries. Five sediment cores (1.5 m in length and diameters of 90 and 160 mm) were taken at a water depth of 12 m. We analysed grain size composition, the concentration of heavy metals and organic pollutants, and radiometrically dated the sediment using 210Pb. Furthermore, we dated shells of the abundant bivalve species Corbula gibba using 14C calibrated amino acid-racemisation (AAR). The whole molluscan community in the cores was analysed for species composition, abundance, taxonomic similarity, evidence for ecological interactions (i.e., frequencies of drilling predation) and taphonomic conditions of shells. The granulometric analysis shows that silt and clay dominate equally throughout the cores. Radiometric sediment dating revealed an average sedimentation rate of 2.5 mm/yr during the last 120 years. Shell dating points to a comparable overall core age, with only a few shell specimens being older than 500 years in the deepest core layer. In total, 10,452 mollusc individuals were analysed and 104 species identified. The most abundant bivalve species are Kurtiella bidentata, Corbula gibba and Abra nitida. Turritella communis and Nassarius pygmaeus are the most frequent gastropod species. Down-core changes in species composition

  17. Structural response of reduced scale naval structures under impact tests

    OpenAIRE

    Calle M.A.G.; Oshiro R.E.; Mazzariol L.M.; Alves M.

    2014-01-01

    Scaled models are important in naval engineering since actual ship size makes too expensive to test prototypes. However, the analysis of ship collision events employing naval structures in reduced scale is not an ordinary ship research area. The aim of this work is to create the basis for a posterior similarity study by analysing reduced scale ship structures submitted to impact loads. Two basic naval structures, commonly found in the construction of large ships, were considered for this stud...

  18. ZOOPLANKTON COMMUNITY STRUCTURE OF THE SEA SURFACE MICROLAYER NEAR NUCLEAR POWER PLANTS AND MARINE FISH CULTURE ZONES IN DAYA BAY

    Institute of Scientific and Technical Information of China (English)

    杨宇峰; 王肇鼎; 潘明祥; 焦念志

    2002-01-01

    The authors' surveys in May-June 1999 (two cruises) at six sampling stations near nuclear power plants (NPP) and marine fish culture zones in Daya Bay, Guangdong, revealed species composition, densities and body-size of thesea surface microlayer (SM) zooplankton (>35 μm). Results showed that protozoans and copepod nauplii were the predominant components, accounting for 65.40% to95.56% of total zooplankton in abundance. The size-frequency distributions showed that the frequency of micro-zooplankton (0.02-0.2 mm) reached 0.8235. The SM zooplankton community structure revealed in the present study was quite different from that revealed by investigations in the 1980s in Daya Bay. Difference of sampling method has important influence on the obtained zooplankton community structure. SM zooplankton consisted of micro- and mesozooplankton (0.2-2.0 mm), with micro-zooplankton being predominant. Some possible cause-effect relations between the zooplankton community structure and mariculture, nuclear power plants cooling systems and sampling method are discussed.``

  19. Zooplankton community structure of the sea surface microlayer near nuclear power plants and marine fish culture zones in Daya Bay

    Science.gov (United States)

    Yang, Yu-Feng; Wang, Zhao-Ding; Pan, Ming-Xiang; Jiao, Nian-Zhi

    2002-06-01

    The authors' surveys in May June 1999 (two cruises) at six sampling stations near nuclear power plants (NPP) and marine fish culture zones in Daya Bay, Guangdong, revealed species composition, densities and body-size of the sea surface microlayer (SM) zooplankton (>35 μm). Results showed that protozoans and copepod nauplii were the predominant components, accounting for 65.40% to 95.56% of total zooplankton in abundance. The size-frequency distributions showed that the frequency of micro-zooplankton (0.02 0.2 mm) reached 0.8235. The SM zooplankton community structure revealed in the present study was quite different from that revealed by investigations in the 1980s in Daya Bay. Difference of sampling method has important influence on the obtained zooplankton community structure. SM zooplankton consisted of micro- and mesozooplankton (0.2 2.0 mm), with micro-zooplankton being predominant. Some possible cause-effect relations between the zooplankton community structure and mariculture, nuclear power plants cooling systems and sampling method are discussed.

  20. Influence of phytoplankton diversity and community structure on oyster reproduction (Arcachon Bay, France)

    OpenAIRE

    Gonzales, Arriagada; Bernard, Ismael; Maurer, Daniele; Auby, Isabelle; Gasmi, Sonia; Pouvreau, Stephane; David, Valerie

    2014-01-01

    Arcachon Bay is one of the most important spat-supplying area for the French oyster production. During the last 16 years, the local economic activity of spat production has been threatened recurrently by a high interannual variability of seed harvesting. This threatened spat production was attributed to reproductive problems highlighted by both a delay in oyster spawning and a decrease of small larvae abundances since 1995. Recent works showed that these two reproduction indice...

  1. Ecology of fishes in Upper Newport Bay, California: seasonal dynamics and community structure

    OpenAIRE

    Horn, Michael H.; Allen, Larry G.

    1981-01-01

    A total of 366 bimonthly (January 1978-January 1979) samples taken with six types of gear (otter trawl, gill net, bag seine, small seine, drop net, square enclosure - all with replication except the gill net) at four stations in upper Newport Bay, California yielded 51,816 fishes belonging to 46 species and weighing over 353 kg. Atherinops affinis (topsmelt) was the most abundant species accounting for 76% of total individuals. Seven species, all of low trophic levels, made up over 97% ...

  2. Zonation and structuring factors of meiofauna communities in a tropical seagrass bed (Gazi Bay, Kenya)

    OpenAIRE

    M. De Troch; Gurdebeke, S.; Fiers, F.; Vincx, M.

    2001-01-01

    This study deals with the relation between tropical meiofauna and environmental variables by comparing the 'benthic' (i.e. in the bare sediment adjacent to seagrass plants) and the 'epiphytic' (i.e. in samples including seagrass plants) meiofauna associated with five seagrass species from the high intertidal to the high subtidal zone in Gazi Bay (Kenya). Ordination and variance analysis revealed three distinct 'benthic' and two 'epiphytic' meiofauna assemblages. These assemblages corresponded...

  3. Diversity and structure of nematode communities across mangrove and seagrass vegetations at Gazi Bay, Kenya

    OpenAIRE

    C. Bezerra, T.N.; Mesel, I. de; Bouillon, S.; Vanreusel, A.; T. Moens

    2007-01-01

    Mangrove benthos has long been assumed to rely primarily on mangrove litter fall, but in recent years, several studies have shown that bacteria, macrobenthos and meiobenthos may preferentially utilize more labile sources such as microphytobenthos and inwelled phytoplankton and seagrass detritus from adjacent shallow waters. The relative importance of these different carbon sources for different consumer taxa, however, remains unclear. We have studied the meiofauna at Gazi Bay, Kenya, based up...

  4. Structural Health Monitoring for Impact Damage in Composite Structures.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis P.; Raymond Bond (Purdue); Doug Adams (Purdue)

    2014-08-01

    Composite structures are increasing in prevalence throughout the aerospace, wind, defense, and transportation industries, but the many advantages of these materials come with unique challenges, particularly in inspecting and repairing these structures. Because composites of- ten undergo sub-surface damage mechanisms which compromise the structure without a clear visual indication, inspection of these components is critical to safely deploying composite re- placements to traditionally metallic structures. Impact damage to composites presents one of the most signi fi cant challenges because the area which is vulnerable to impact damage is generally large and sometimes very dif fi cult to access. This work seeks to further evolve iden- ti fi cation technology by developing a system which can detect the impact load location and magnitude in real time, while giving an assessment of the con fi dence in that estimate. Fur- thermore, we identify ways by which impact damage could be more effectively identi fi ed by leveraging impact load identi fi cation information to better characterize damage. The impact load identi fi cation algorithm was applied to a commercial scale wind turbine blade, and results show the capability to detect impact magnitude and location using a single accelerometer, re- gardless of sensor location. A technique for better evaluating the uncertainty of the impact estimates was developed by quantifying how well the impact force estimate meets the assump- tions underlying the force estimation technique. This uncertainty quanti fi cation technique was found to reduce the 95% con fi dence interval by more than a factor of two for impact force estimates showing the least uncertainty, and widening the 95% con fi dence interval by a fac- tor of two for the most uncertain force estimates, avoiding the possibility of understating the uncertainty associated with these estimates. Linear vibration based damage detection tech- niques were investigated in the

  5. Intraguild predation between small pelagic fish in the Bay of Biscay: impact on anchovy (Engraulis encrasicolus L.) egg mortality

    KAUST Repository

    Bachiller, Eneko

    2015-05-12

    Small pelagic fish can play an important role in various ecosystems linking lower and upper trophic levels. Among the factor behind the observed inter-annual variations in small pelagic fish abundance, intra- and inter-specific trophic interactions could have a strong impact on the recruitment variability (e.g. anchovy). Egg cannibalism observed in anchovies has been postulated to be a mechanism that determines the upper limit of the population density and self-regulates the population abundance of the species. On the other hand, predation by other guild species is commonly considered as a regulation mechanism between competing species. This study provides empirical evidence of anchovy cannibalism and predation of the main small pelagic fish species on anchovy eggs and estimates the effect of intraguild predation on the anchovy egg mortality rate. Results show that, depending on the year (2008–2009), up to 33 % of the total anchovy egg mortality was the result of sardine predation and up to 4 % was the result of egg cannibalism together with predation by Atlantic and Atlantic Chub mackerel and sprat. Results also indicate that in the Bay of Biscay, fluctuations in the survival index of the early life stages of anchovy are likely to be attributable at least in part to egg cannibalism and especially to a high sardine predation on anchovy eggs. © 2015 Springer-Verlag Berlin Heidelberg

  6. Structural health monitoring and impact detection for primary aircraft structures

    Science.gov (United States)

    Kosters, Eric; van Els, Thomas J.

    2010-04-01

    The increasing use of thermoplastic carbon fiber-reinforced plastic (CFRP) materials in the aerospace industry for primary aircraft structures, such as wing leading-edge surfaces and fuselage sections, has led to rapid growth in the field of structural health monitoring (SHM). Impact, vibration, and load can all cause failure, such as delamination and matrix cracking, in composite materials. Moreover, the internal material damage can occur without being visible to the human eye, making inspection of and clear insight into structural integrity difficult using currently available evaluation methods. Here, we describe the detection of impact and its localization in materials and structures by high-speed interrogation of multiple-fiber Bragg grating (FBG) sensors mounted on a composite aircraft component.

  7. Subcellular partitioning profiles and metallothionein levels in indigenous clams Moerella iridescens from a metal-impacted coastal bay.

    Science.gov (United States)

    Wang, Zaosheng; Feng, Chenglian; Ye, Chun; Wang, Youshao; Yan, Changzhou; Li, Rui; Yan, Yijun; Chi, Qiaoqiao

    2016-07-01

    In this study, the effect of environmental metal exposure on the accumulation and subcellular distribution of metals in the digestive gland of clams with special emphasis on metallothioneins (MTs) was investigated. Specimens of indigenous Moerella iridescens were collected from different natural habitats in Maluan Bay (China), characterized by varying levels of metal contamination. The digestive glands were excised, homogenized and six subcellular fractions were separated by differential centrifugation procedures and analyzed for their Cu, Zn, Cd and Pb contents. MTs were quantified independently by spectrophotometric measurements of thiols. Site-specific differences were observed in total metal concentrations in the tissues, correlating well with variable environmental metal concentrations and reflecting the gradient trends in metal contamination. Concentrations of the non-essential Cd and Pb were more responsive to environmental exposure gradients than were tissue concentrations of the essential metals, Cu and Zn. Subcellular partitioning profiles for Cu, Zn and Cd were relatively similar, with the heat-stable protein (HSP) fraction as the dominant metal-binding compartment, whereas for Pb this fraction was much less important. The variations in proportions and concentrations of metals in this fraction along with the metal bioaccumulation gradients suggested that the induced MTs play an important role in metal homeostasis and detoxification for M. iridescens in the metal-contaminated bay. Nevertheless, progressive accumulation of non-essential metals (Cd, and especially Pb) resulting from "spillover" was observed in putative metal- sensitive (e.g., mitochondria and heat-denaturable protein (HDP)) or lysosome/microsome fractions, demonstrating that metal detoxification was incomplete and increased the toxicological risk to M. iridescens inhabiting the metal-impacted environments. Through multiple stepwise regression analysis, the induction of MTs was statistically

  8. Materials and structures under shock and impact

    CERN Document Server

    Bailly, Patrice

    2013-01-01

    In risk studies, engineers often have to consider the consequences of an accident leading to a shock on a construction. This can concern the impact of a ground vehicle or aircraft, or the effects of an explosion on an industrial site.This book presents a didactic approach starting with the theoretical elements of the mechanics of materials and structures, in order to develop their applications in the cases of shocks and impacts. The latter are studied on a local scale at first. They lead to stresses and strains in the form of waves propagating through the material, this movement then extending

  9. Genetic Diversity Analysis of the Natural Populations of Mediterra­nean Mussels [Mytilus galloprovincialis (Lmk.] in Agadir Bay: Assess­ment of the Molecular Polymorphism and Environmental Impact

    Directory of Open Access Journals (Sweden)

    Amal Korrida

    2010-07-01

    Full Text Available Mediterranean mussel (Mytilus galloprovincialis Lmk has a great environmental and economic importance for Morocco. This work studies the genetic structure and impact of chemical pollution on three different marine populations of Mytilus galloprovincialis that live within Agadir bay. Three collections were made at two clean sites (Cape Ghir and Cape Aglou and at an impacted site exposed to intense boating and industrial activities (Anza. A 300-bp portion of the mitochondrial DNA coding-region Cytochrome C Oxidase subunit 1 (COI was studied by polymerase chain reaction (PCR and DNA sequencing reactions to assess and evaluate amounts of polymorphism in each site. Genetic analysis using COI for 64 individuals showed no significant differentiation between the three subpopulations. AMOVA demonstrated that only 2.83% of variation exists between populations. Besides the genetic evidence presented herein, mussel’s adaptation mechanisms and strategies to marine pollution are also discussed.

  10. Watershed and Hydrodynamic Modeling for Evaluating the Impact of Land Use Change on Submerged Aquatic Vegetation and Seagrasses in Mobile Bay

    Science.gov (United States)

    Estes, Maurice G.; Al-Hamdan, Mohammed; Thom, Ron; Quattrochi, Dale; Woodruff, Dana; Judd, Chaeli; Ellism Jean; Watson, Brian; Rodriguez, Hugo; Johnson, Hoyt

    2009-01-01

    There is a continued need to understand how human activities along the northern Gulf of Mexico coast are impacting the natural ecosystems. The gulf coast is experiencing rapid population growth and associated land cover/land use change. Mobile Bay, AL is a designated pilot region of the Gulf of Mexico Alliance (GOMA) and is the focus area of many current NASA and NOAA studies, for example. This is a critical region, both ecologically and economically to the entire United States because it has the fourth largest freshwater inflow in the continental USA, is a vital nursery habitat for commercially and recreational important fisheries, and houses a working waterfront and port that is expanding. Watershed and hydrodynamic modeling has been performed for Mobile Bay to evaluate the impact of land use change in Mobile and Baldwin counties on the aquatic ecosystem. Watershed modeling using the Loading Simulation Package in C++ (LSPC) was performed for all watersheds contiguous to Mobile Bay for land use Scenarios in 1948, 1992, 2001, and 2030. The Prescott Spatial Growth Model was used to project the 2030 land use scenario based on observed trends. All land use scenarios were developed to a common land classification system developed by merging the 1992 and 2001 National Land Cover Data (NLCD). The LSPC model output provides changes in flow, temperature, sediments and general water quality for 22 discharge points into the Bay. These results were inputted in the Environmental Fluid Dynamics Computer Code (EFDC) hydrodynamic model to generate data on changes in temperature, salinity, and sediment concentrations on a grid with four vertical profiles throughout the Bay s aquatic ecosystems. The models were calibrated using in-situ data collected at sampling stations in and around Mobile bay. This phase of the project has focused on sediment modeling because of its significant influence on light attenuation which is a critical factor in the health of submerged aquatic

  11. The Nottawa-Broadback-Rupert complex: Rupert Bay biophysical study programs

    International Nuclear Information System (INIS)

    In the construction of the Nottaway-Broadback-Rupert (NBR) hydroelectric complex, the modification of the natural environment in Rupert Bay, notably of migratory bird habitats, is one of the major environmental impacts to be considered. After a description of the Rupert Bay environment, Hydro-Quebec's program of physical and biological studies to assess the environmental impact of the NBR complex is described. Rupert Bay, the natural continuation of James Bay, has a surface area of 850 km2 and contains an important estuary common to four rivers emptying into it. There are three estuarine zones, classified according to the kind of currents and the degree of salt and fresh water mixing. The phytoplankton population structure follows the salinity distribution and the nature of exchanges among the three zones. The bay is surrounded by vast marine intertidal zones which are preferred habitats for many species of fish, birds, and small aquatic mammals. Three major sources of impact were identified as having consequences on the Rupert Bay environment: the diversion and management of water flows; the creation of reservoirs; and the consequences of NBR development, such as possible erosion of downstream riverbanks. Concerns of local Cree communities on the possible effects of NBR were incorporated into the study program. Physical studies included analyzing the dynamics of the bay and developing mathematical models to predict modifications due to operation of the NBR complex. The biological studies included inventories of species found in the bay and oceanographic studies to determine the influence of fresh water on primary production

  12. Effects of a nuclear power plant thermal discharge on habitat complexity and fish community structure in Ilha Grande Bay, Brazil

    OpenAIRE

    Teixeira, Tatiana Pires; Neves, Leonardo Mitrano; Araújo, Francisco Gerson

    2009-01-01

    Abstract Fish communities and habitat structures were evaluated by underwater visual censuses a rocky location impacted by thermal discharge (I) and at two control locations, one in a Sargassum bed (C1) and the other in a rocky shore with higher structural complexity (C2). Habitat indicators and fish communities exhibited significant differences between the impacted and control locations, with the impacted one showing a significant decrease in fish species richness and diversity, a...

  13. Copper and Other Contaminants in King's Bay and Crystal River (Florida) Sediments: Implications for Impact on the West Indian Manatee

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Contaminant concentrations were measured in 25 sediment samples collected from King's Bay, the headwaters of the Crystal River, Florida. Total organic carbon...

  14. Impact of the commercial fishery on the population of bait shrimp (Penaeus spp.) in Biscayne Bay, 1986

    OpenAIRE

    Campos, W. L.; Berkeley, S.A.

    2003-01-01

    Monthly population size of bait shrimp in the Bay was estimated from December 1984 to July 1985. Growth rates for male and female P. duorarum showed that pink shrimp exhibit a mean residence time in the nursery area (Biscayne Bay) of approximately 21 weeks. Monthly mortality rates were determined for each sex of pink shrimp. It was estimated that 23% and 26% of the male and female monthly population size, respectively, was absorbed by both the fishery and ecosystem monthly. Monthly prop...

  15. The Impact of Sound Structure on Morphology

    DEFF Research Database (Denmark)

    Laaha, Sabine; Kjærbæk, Laila; Basbøll, Hans;

    2011-01-01

    This study examines the impact of sound structure on children’s acquisition of noun plural morphology, focussing on stem change. For this purpose, a threelevel classification of stem change properties according to sound structure is presented, with increasing opacity of the plural stem: no change......, weak change, strong change. General hypotheses are presented as well as predictions following from them, both general and language-specific. The relevance of stem change is tested in 140 German-speaking and 140 Danish-speaking children from the age of three to nine years, by using a plural elicitation...... task. Results show that in both languages, stem change has an impact on children’s correct production of plural stems. Language-specific differences between German and Danish both in correct responses and in overgeneralization errors are compared to our predictions and discussed in detail....

  16. Structural response of reduced scale naval structures under impact tests

    Directory of Open Access Journals (Sweden)

    Calle M.A.G.

    2014-01-01

    Full Text Available Scaled models are important in naval engineering since actual ship size makes too expensive to test prototypes. However, the analysis of ship collision events employing naval structures in reduced scale is not an ordinary ship research area. The aim of this work is to create the basis for a posterior similarity study by analysing reduced scale ship structures submitted to impact loads. Two basic naval structures, commonly found in the construction of large ships, were considered for this study: a T cross-section beam submitted to a mid-span impact test and a double plate panel with inner cross reinforcement also submitted to a central impact load. These models were made in a reduced scale of 1:100. The experimental material characterization was also carried out in this work, including the evaluation of the stress strain curve under quasi static conditions, the strain rate sensitivity and the structural failure using three criteria developed particularly for numerical modelling of ship collision by other authors.

  17. Food insecurity, chronic illness, and gentrification in the San Francisco Bay Area: An example of structural violence in United States public policy.

    Science.gov (United States)

    Whittle, Henry J; Palar, Kartika; Hufstedler, Lee Lemus; Seligman, Hilary K; Frongillo, Edward A; Weiser, Sheri D

    2015-10-01

    Food insecurity continues to be a major challenge in the United States, affecting 49 million individuals. Quantitative studies show that food insecurity has serious negative health impacts among individuals suffering from chronic illnesses, including people living with HIV/AIDS (PLHIV). Formulating effective interventions and policies to combat these health effects requires an in-depth understanding of the lived experience and structural drivers of food insecurity. Few studies, however, have elucidated these phenomena among people living with chronic illnesses in resource-rich settings, including in the United States. Here we sought to explore the experiences and structural determinants of food insecurity among a group of low-income PLHIV in the San Francisco Bay Area. Thirty-four semi-structured in-depth interviews were conducted with low-income PLHIV receiving food assistance from a local non-profit in San Francisco and Alameda County, California, between April and June 2014. Interview transcripts were coded and analysed according to content analysis methods following an inductive-deductive approach. The lived experience of food insecurity among participants included periods of insufficient quantity of food and resultant hunger, as well as long-term struggles with quality of food that led to concerns about the poor health effects of a cheap diet. Participants also reported procuring food using personally and socially unacceptable strategies, including long-term dependence on friends, family, and charity; stealing food; exchanging sex for food; and selling controlled substances. Food insecurity often arose from the need to pay high rents exacerbated by gentrification while receiving limited disability income--​a situation resulting in large part from the convergence of long-standing urban policies amenable to gentrification and an outdated disability policy that constrains financial viability. The experiences of food insecurity described by participants in this

  18. Concrete structures under impact and impulsive loading

    International Nuclear Information System (INIS)

    This book contains papers contributed to the RILEM/CEB/IABSE/IASS-Interassociation Symposium on 'Concrete Structures under Impact and Impulsive Loading'. The essential aim of this symposium is to provide an international forum for the exchange of information on existing and current research relating to impact problems as well as to identify areas to which further research activities should be directed. The subject of the symposium is far ranging. Fifty five papers were proposed and arranged in six technical sessions, a task which sometimes posed difficulties for the Organization Committee and the Advisory Group, because some of the papers touched several topics and were difficult to integrate. However, we are confident that these minor difficulties were solved to the satisfaction of everyone involved. Each session of the symposium is devoted to a major subject area and introduced by a distinguished Introductory Reporter. The large international attendance, some 21 countries are represented, and the large number of excellent papers will certainly produce a lively discussion after each session and thus help to further close the gaps in our knowledge about the behaviour of structures and materials under impact and impulsive loading. (orig./RW)

  19. Impact of river discharge on distribution of dimethyl sulfide (DMS) and its fluxes in the coastal Bay of Bengal

    Science.gov (United States)

    Rao, V. D.; Viswanadham, R.; Bharathi, M. D.; Sarma, V. V. S. S.; Kumar, M. D.

    2015-09-01

    A systematic study was conducted to examine the influence of river discharge on variations in DMS and DMSPt during peak discharge period along the coastal Bay of Bengal. The southern coastal Bay of Bengal (SCB) received a large quantity of suspended particulate matter (SPM) and nitrogen nutrients from the monsoonal estuaries and vice versa to the northern coastal Bay of Bengal (NCB) by glacial river (Ganges). The higher concentration of DMSPt was observed in the NCB compared with SCB associated with low nitrate, and low salinity suggesting that their stress on phytoplankton increased DMSPt production in the former region. The concentrations of DMS and DMSPt in the surface waters displayed a linear relation with biovolume of Bacillariophyceae and Dinophyceae suggesting significant contributions by these two groups. In contrast, the weak spatial variability in DMS was attributed to removal of DMS to the atmosphere or bacterial consumption. The mean sea-to-air flux of DMS amounted to 5.5 ± 4 μmol S m- 2 d- 1 suggesting that the coastal Bay of Bengal is a significant source to atmospheric DMS during study period. This study revealed that river discharge brought a significant modification in the chemical characteristics of the coastal Bay of Bengal leading to variable stress (salinity and nutrients) on phytoplankton resulting in a significant flux of DMS to the atmosphere.

  20. Near-Surface Structure of the Peninsula Segment of the San Andreas Fault, San Francisco Bay Area, California

    Science.gov (United States)

    Rosa, C.; Catchings, R.; Rymer, M. J.; Goldman, M.; Grove, K.; Prentice, C. S.

    2013-12-01

    The peninsula segment of the San Andreas Fault (SAF) is a section of the fault that has the potential to produce the next large earthquake in the San Francisco Bay Area, yet the slip history of the peninsula segment is relatively unknown. In most places, the surface location of the SAF has been determined primarily on the basis of geomorphic features and from mapping surface ruptures associated with the 1906 M7.9 San Francisco earthquake. To more precisely locate traces of the SAF along the San Francisco peninsula in the subsurface, we acquired a high-resolution seismic imaging survey, using both seismic refraction and reflection profiling, south of Upper Crystal Springs Reservoir near Woodside, California in June 2012. We acquired coincident P- and S-wave data using a 60-channel seismograph system connected via cable to 40-Hz vertical-component and 4-Hz horizontal-component geophones, with spacing at 1-m intervals along a 60-m-long transect across the SAF. Seismic sources (shots) were generated by hammer impacts on a steel plate or aluminum block at each geophone location. All shots were recorded on all channels. This survey design permitted simultaneous acquisition of reflection and refraction data such that both refraction tomography and reflection images were developed. Analysis of the P- and S-wave data, using refraction tomography, shows abrupt variations in the P-wave (Vp) and S-wave (Vs) velocities, including the 1,500 m/s velocity contour that outlines the top to groundwater and images of Vp/Vs and Poisson's ratios. P-wave velocities range from about 700 m/s at the surface to more than 4000 m/s at 20-m depth. S-wave velocities range from about 300 m/s at the surface to about 800 m/s at 20-m depth. The combined data indicate that the near-surface trace of the SAF dips steeply to the southwest in the upper few tens of meters. Variations in the velocity images also suggest the possibility of two additional near-surface fault traces within about 25 m of the

  1. Navidad development in the southern Bay of Biscay: Climate change and swoddy structure from remote sensing and in situ measurements

    Science.gov (United States)

    Garcia-Soto, Carlos; Pingree, Robin D.; Valdés, Luis

    2002-08-01

    The warm water extension of the Iberian Poleward Current off northern Spain (``Navidad'') was examined in the advanced very high resolution radiometer (AVHRR) satellite archive (1979-2000) and in a time series of January sea surface temperatures. Winter warming in the southern Bay of Biscay during Navidad years was correlated with low values of the North Atlantic Oscillation (NAO) Index for the preceding months (November-December). Exceptional Navidad development and winter warming were observed during January 1990, January 1996, and January 1998, and extensive measurements were gathered for these 3 years. The Eastern Boundary poleward warming was found to extend from Portugal to Norway in exceptional Navidad years. The long-term changes of SST in the Navidad region (1967-2000) were analyzed in the frame of the decadal variation for the Celtic shelf (1890-2000), which showed an increase of 1°C over the century. During January 1990 and January 1996, cloud-free images of Navidad showed a pronounced production of slope water oceanic eddies (swoddies) in the SE corner of the Bay of Biscay. The small-scale properties of one of these swoddies (F90) were analyzed during summer from measurements at sea (RRS Discovery 193 cruise; July 1990). SeaSoar sections showed the physical structure of the swoddy core. The distribution and abundance of chlorophyll a associated with the swoddy was determined. It is shown that a swoddy has a higher chlorophyll a maximum in the seasonal thermocline than associated cyclones. Simultaneous satellite observations of the sensors AVHRR, Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and altimeter (combined TOPEX/Poseidon/ERS-2 data) were used to analyze the remote sensing properties of three summer swoddy-like eddies during August 1998. The summer SeaWiFS chlorophyll a concentration at the center of the eddy near 45.5°N, 6°W (AE6) was appraised against a time series (September 1997 to April 2001) of SeaWiFS chlorophyll a concentration

  2. Hail ice impact on composite structures at glancing angles

    OpenAIRE

    Funai, Sho

    2012-01-01

    Aircraft structures are susceptible to damage due to high velocity hail ice impact. These impacts can create nonvisible damage in the structure, jeopardizing its structural integrity. Experiments were completed with simulated hail ice (SHI) impacting T800/3900-2 carbon/ epoxy tape laminates and aluminum panels at various angles. The angled impacts were similar to the normal impacts in the failure propagation of ice as well as the size and shape of the delaminations. Experimental failure thres...

  3. Geogenic metal mobility in a coastal inlet impacted by cannery discharge, Magdalena Bay, Baja California Sur, Mexico.

    Science.gov (United States)

    O'Shea, Beth; Capistrano, Christian; Lee, William

    2016-08-15

    Magdalena Bay is an important habitat for marine organisms, some of which have been the subject of metal bioaccumulation studies. Cannery waste is discharged into the bay providing a plausible source of contamination but this study finds that some metals occur geogenically. Bay sediments and rocks (n=59) were analyzed for total metals and clustered (HCA) into two distinct groups with PCA indicating concentrations of Cr, Cu, Mn, and Ni influenced samples near ophiolite outcrops, which reported some metal concentrations exceeding averages in the crust by an order of magnitude (up to 4450ppm Cr and 1269ppm Ni). Metals at the cannery are rarely elevated above crustal averages except Zn (max. 160ppm), however, acid-extracted Zn was below recommended sediment quality guidelines in contrast to 80% of ophiolitic samples reporting Ni extractability exceeding such guidelines. This study raises awareness of geogenic metals when considering sources of contamination in marine environments. PMID:27251444

  4. Concrete structures under impact loading: general aspects

    Directory of Open Access Journals (Sweden)

    Cornelia Baeră

    2016-09-01

    Full Text Available Dynamic loading conditions distress the structural integrity of a structure differently than the static ones. Such actions transfer high rate strains and instant energy waves to the structure, inducing the possibility of imminent collapse and casualties as a direct consequence. In the latest years, considering the dramatic increase of terrorist threats and global warming, the structural safety criteria imply more than ever the need to withstand this kind of loading (e.g., missiles and blast, projectiles, strong winds, tornados and earthquakes in addition to the static ones. The aim of this paper is to provide a general overview with regard to impact loading in terms of defining the phenomenon from physical and mechanical perspective, its complex local or global effect on the targeted structure, relevant material characteristics, main research approaches, namely theoretical studies and experimental procedures developed for improving the predictability of the dynamic loads and their effects. New directions in developing superior cementitious composites, with better characteristics in terms of dynamic loading performance are also emphasized.

  5. Environmental impact analysis of coastal exploitation in Dalian Bay%海岸带开发活动对大连湾环境影响分析

    Institute of Scientific and Technical Information of China (English)

    王伟伟; 王鹏; 吴英超; 马红伟

    2011-01-01

    为正确评价海岸带开发活动对大连湾海域产生的影响,本文从围填海活动和临海工业两个方面对海岸带开发活动产生的环境效应影响做了趋势性分析,并根据搜集的2005~2008年的水质监测数据对大连湾海域进行了海洋环境质量评价.研究表明,2000~2009年,大连湾海域面积减少了约900 hm2,自然岸线减少了约4 km;临海工业的污染物排放导致海水环境恶化;根据水质数据监测结果,大连湾海域超标的污染物主要为无机氮、磷酸盐和油类.%In order to the correct guidance of coastal exploitations in Dalian Bay, the trend analysis of the environmental impact of coastal exploitations was done based on the reclamation project and coastal industry. The data collected from the marine environmental monitoring in Dalian Bay 2003 ~ 2008 were used to evaluate the seawater quality. The results showed that the study area in Dalian Bay was decreased nearly 900 hectares and natural coastline decreased about 4 km due to the reclamation activities from 2000 to 2009. The pollutants discharged from industries around the coast lead to the marine environment deterioration. According to the monitoring results of water quality, the main pollutants in Dalian Bay were inorganic nitrogen, phosphorus and oil.

  6. Investigation of 3-D basin structures in the İzmit Bay area (Turkey) by single-station microtremor and gravimetric methods

    Science.gov (United States)

    Özalaybey, Serdar; Zor, Ekrem; Ergintav, Semih; Tapırdamaz, M. Cengiz

    2011-08-01

    We investigate 3-D basin structures and site resonance frequencies in the İzmit Bay area of Turkey by new geophysical surveys based on 239 single station microtremor and 405-point gravity measurements. A fundamental resonance frequency map of the İzmit Bay was produced from the main peak in the horizontal-to-vertical component spectral ratio (HVSR) of microtremors. The HVSR analysis of the microtremor data reveals single, double, broad peaked or no peak type HVSR curves varying in accordance with the surface geology and spatial extent of the three basins present in the İzmit Bay area. In the deepest sections of the İzmit, Gölcük and Derince basins of the İzmit Bay, the fundamental resonance frequencies are dominantly 0.24-0.30 Hz. These resonance frequencies should be taken into consideration along with higher mode frequencies to construct earthquake resistant structures in the İzmit Bay area. The 3-D gravimetric bedrock depth map of the İzmit basin shows that the basin has an asymmetric shape with its deepest section coinciding with the surface trace of the North Anatolian Fault. The northern shoulder of the basin has a gentle dip on the Kocaeli Peneplain side and the southern shoulder is much steeper, and it is bounded by the Samanlı Mountains. We derive a power-law relationship that correlates the fundamental site resonance frequencies with the sedimentary cover thickness obtained from the gravity and shear wave velocity data in the İzmit Bay. We use this relationship to estimate bedrock depths beneath Gölcük and Derince basins. Our estimation of maximum basin depths is 1400 m for the İzmit and is 800 m for the Gölcük and Derince basins. Finally, we have analysed a converted Sp phase from a local earthquake recording made at site CMP to calculate and verify the sediment thickness estimations obtained from our gravimetric and microtremor analyses. This calculation shows close agreement with that of the gravimetric and microtremor results. Our

  7. Load test of the 277W Building high bay roof deck and support structure

    International Nuclear Information System (INIS)

    The 277W Building high bay roof area was load tested according to the approved load-test procedure, WHC-SD-GN-TP-30015, Revision 1. The 277W Building is located in the 200 West Area of the Hanford Site and has the following characteristics: roof deck -- wood decking supported by 4 x 14 timber purlins; roof membrane -- tar and gravel; roof slope -- flat (<10 deg); and roof elevation -- maximum height of about 63 ft. The 227W Building was visited in March 1994 for a visual inspection. During this inspection, cracked areas were visible in the decking, but it was not possible to determine whether these cracks extended completely through the decking, which is 2-in. thick. The building was revisited in March 1994 for the purpose of writing this test report. Because the roof requires personnel access, a test was determined to be the best way to qualify the roof. The conclusions are that the roof has been qualified for 500-lb total roof load and that the ''No Roof Access'' signs can be changed to ''Roof Access Restricted'' signs

  8. Picoplankton and virioplankton abundance and community structure in Pearl River Estuary and Daya Bay, South China.

    Science.gov (United States)

    Ni, Zhixin; Huang, Xiaoping; Zhang, Xia

    2015-06-01

    By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer of 2012. We identified two subgroups of prokaryotes, high nucleic acid (HNA) and low nucleic acid (LNA), characterized by different nucleic acid contents. HNA abundance was significantly correlated with larger phytoplankton and Synechococcus (Syn) abundance, which suggested the important role of organic substrates released from primary producers on bacterial growth. Although LNA did not show any association with environmental variables, it was a vital component of the microbial community. In contrast to previous studies, the total virioplankton concentration had a poor relationship with nutrient availability. The positive relationship between large-sized phytoplankton abundance and the V-I population confirmed that V-I was a phytoplankton-infecting viral subgroup. Although the V-II group (bacteriophages) was dominant in the virioplankton community, it was not related with prokaryotic abundance, which indicated factors other than hosts controlling V-II abundance or the uncertainty of virus-host coupling. With respect to the picophytoplankton community, our results implied that river input exerted a strong limitation to Syn distribution in the estuary, while picoeukaryotes (Euk) were numerically less abundant and showed a quite different distribution pattern from that of Syn, and hence presented ecological properties distinct from Syn in our two studied areas. PMID:26040741

  9. Seasonality of community structure and carbon flow in Narragansett Bay sediments

    International Nuclear Information System (INIS)

    Seasonal patterns of benthic community dynamics and the pathways of detrital decomposition in Narragansett Bay were examined. Benthic meiofauna and macrofauna exhibited a pronounced seasonality, with peak abundances in the late spring and minima in the late summer. This pattern was most pronounced for surface dwelling fauna, particularly harpacticoid copepods. These results were attributed to the seasonality of detrital inputs to the sediment and the fate of these inputs. A six month study in which 14C-sodium bicarbonate was added to a large (13 m3) microcosm enabled the author to observe pathways of carbon flow. Half of the labeled organic carbon that was deposited on the sediment during the winter and spring was found in the sediment in July. At least 20 gC/m2 had accumulated since December. Within the sediment, the existence of two discrete food webs was distinguished by measurement of faunal specific activity. Surface fauna, dominated by the meiofauna, exclusively assimilate fresh (labeled) organics, while subsurface fauna (meiofauna and macrofauna) predominantly assimilated older, non-labeled organics for the duration of the study. Only the subsurface food web had access to the storage of buried detritus. While there was a surplus of detritus for both food webs during the winter and spring, the authors expect that benthic respiration rates exceed organic deposition rates during the summer. Detrital storage may be critical for the survival of the fauna through the summer

  10. Broadband Seismic Deployments for Imaging the Upper Mantle Structure in the Lützow-Holm Bay Region, East Antarctica

    Directory of Open Access Journals (Sweden)

    Masaki Kanao

    2011-01-01

    Full Text Available Broadband seismic deployments have been carried out in the Lützow-Holm Bay region (LHB, Dronning Maud Land, East Antarctica. The recorded teleseismic and local events are of sufficient quality to image the structure and dynamics of the crust and mantle of the terrain. Passive seismic studies by receiver functions and shear wave splitting suggest a heterogeneous upper mantle. Depth variations in topography for upper mantle discontinuities were derived from long period receiver function, indicating a shallow depth discontinuity at 660 km beneath the continental area of LHB. These results provide evidence of paleo upwelling of the mantle plume associated with Gondwana break-up. SKS splitting analysis anticipated a relationship between “fossil” anisotropy in lithospheric mantle and past tectonics. Moreover, active source surveys (DSSs imaged lithospheric mantle reflections involving regional tectonic stress during Pan-African and succeeding extension regime at the break-up. By combining the active and passive source studies of the mantle structure, we propose an evolution model of LHB for constructing the present mantle structure.

  11. Satellite Remote Sensing Signatures of Impact Structures

    Science.gov (United States)

    Garvin, J. B.; Grieve, R. A. F.; Schnetzler, C. C.

    1995-09-01

    On Earth the impact record is preserved in the form of ~140 landforms [1], although current cratering flux estimates [2] suggest that hundreds of structures remain undiscovered on the terrestrial continents. A primary focus of our ongoing research efforts in this area has necessarily emphasized the geologically most recent impact events, especially those which formed in the last few million years. For example, we have comprehensively examined the orbital remote sensing characteristics of the Zhamanshin impact feature of Kazakhstan, a ~ 14 km diameter complex crater which apparently formed only ~870,000 years ago in a mixed sedimentary target [3]. In this case, we have been most fortunate to have available TM, SPOT Panchromatic (i.e, 10 m spatial resolution), SRL-1 and SRL-2 multiparameter SAR, and a ~ 90 m horizontal resolution DEM, along with excellent field data. The orbital multispectral data (TM) allowed us to discriminate the larger deposits of allogenic breccias at this youthful feature from erosionally emplaced surficial units, and a subtle signature of those areas covered with lag deposits of impact-related glass (zhamanshinites) was also identified [3,4]. As part of an ongoing collaboration with SRL scientists R. Greeley and D. Blumberg, we have also observed that L-band orbital SAR data clearly reveals the subtleties of the drainage networks that developed as a consequence of the cratering event, and which are apparently controlled by crater-related structures and deposit porosities [5]. When the geomorphically subtle Zhamanshin feature is compared against the Bosumtwi crater of Ghana, which apparently formed in crystalline shield rocks at around the same time (~ 1 million years ago), it appears that target rock properties have strongly influenced the level of preservation of these craters. Indeed, SPOT XS remote sensing data for Bosumtwi reveals a relatively pristine "lunar-like" complex crater with a raised rim, a quasi-polygonal outline, and a deep

  12. Investigation on the distribution and fate of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in a sewage-impacted bay

    International Nuclear Information System (INIS)

    The distribution and fate of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) were investigated in the water and sediment of Bohai Bay, China, during 2011–2013. A total of 360 water samples and 60 sediment samples were collected from 20 locations. The median concentrations of PFOS and PFOA were 4.8 and 12.15 ng/L in the water, and 2.65 and 0.62 ng/g-dry in the sediment, respectively. Significant enrichment were observed for PFOS and PFOA in water of sea surface microlayer. The concentrations of these two compounds showed an apparent gradient from nearshore to offshore stations. The correlation analysis and the distribution tendencies indicated that freshwater inflowing to the bay was the main source of PFOS and PFOA. The salinity of seawater and the total organic carbon (TOC) content of sediment heavily affected the spatial distribution and the partitioning of PFOS and PFOA in the sediment-water system. - Highlights: • We investigated the distribution and partitioning of PFOS and PFOA in Bohai Bay. • The PFOS and PFOA concentration showed a gradient from nearshore to offshore sites. • The PFOS and PFOA enriched significantly in the sea surface microlayer of water. • Inflowing freshwater was the main source of PFOS and PFOA in Bohai Bay. • Salinity and TOC deeply affected the distribution and partitioning of PFOS and PFOA. - The spatial and temporal distribution and the partitioning of perfluorooctane sulfonate and perfluorooctanoate were determined in the seawater-sediment system of Bohai Bay

  13. Lithosphere Structure and upper mantle characteristics below the Bay of Bengal

    Science.gov (United States)

    Rao, G. Srinivasa; Radhakrishna, M.; Sreejith, K. M.; Krishna, K. S.; Bull, J. M.

    2016-04-01

    The oceanic lithosphere in the Bay of Bengal (BOB) formed 80-120 Ma following the breakup of eastern Gondwanaland. Since its formation, it has been affected by the emplacement of two long N-S trending linear aseismic ridges (85oE and Ninetyeast) and by the loading of ca. 20-km of sediments of the Bengal Fan. Here, we present the results of a combined spatial and spectral domain analysis of residual geoid, bathymetry and gravity data constrained by seismic reflection and refraction data. Self-consistent geoid and gravity modeling defined by temperature-dependent mantle densities along a N-S transect in the BOB region revealed that the depth to the Lithosphere-Asthenosphere boundary (LAB) deepens steeply from 77 km in the south to 127 km in north, with the greater thickness being anomalously thick compared to the lithosphere of similar-age beneath the Pacific Ocean. The Geoid-Topography Ratio (GTR) analysis of the 85°E and Ninetyeast ridges indicate that they are compensated at shallow depths. Effective elastic thickness (Te) estimates obtained through admittance/ coherence analysis as well as the flexural modeling along these ridges led to the conclusions: i) 85°E Ridge was emplaced in off-ridge environment (Te = 10-15 km); ii) the higher Te values of ˜25 km over the Afanasy Nikitin Seamount (ANS) reflect the secondary emplacement of the seamount peaks in off-ridge environment, iii) that the emplacement of the Ninetyeast Ridge north of 2°N occurred in an off-ridge environment as indicated by higher Te values (25-30 km). Furthermore, the admittance analysis of geoid and bathymetry revealed that the admittance signatures at wavelengths >800 km are compensated by processes related to upper mantle convection.

  14. CRED Fagatele Bay National Marine Sanctuary Bathymetric Position Index Habitat Structures 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetric Position Index (BPI) Structures are derived from derivatives of Simrad EM-3000 multibeam bathymetry (1 m and 3 m resolution). BPI structures are...

  15. Implications of the Daya Bay observation of θ13 on the leptonic flavor mixing structure and CP violation

    Institute of Scientific and Technical Information of China (English)

    XING Zhi-Zhong

    2012-01-01

    The Daya Bay collaboration has recently reported its first (-V)e → (-V)e oscillation result which points to θ13 (~-) 8.8° ±0.8° (best-fit ±1σ range) or θ13 ≠ 0° at the 5.2σ level.The fact that this smallest neutrino mixing angle is not strongly suppressed motivates us to look into the underlying structure of lepton flavor mixing and CP violation.Two phenomenological strategies are outlined:(1) the lepton flavor mixing matrix U consists of a constant leading term U0 and a small perturbation term AU; and (2) the mixing angles of U are associated with the lepton mass ratios.Some typical patterns of U0 are reexamined by constraining their respective perturbations with current experimental data.We illustrate a few possible ways to minimally correct U0 in order to fit the observed values of three mixing angles.We point out that the structure of U may exhibit an approximate μ-τ permutation symmetry in modulus,and reiterate the geometrical description of CP violation in terms of the leptonic unitarity triangles.The salient features of nine distinct parametrizations of U are summarized,and its Wolfenstein-like expansion is presented by taking U0 to be the democratic mixing pattern.

  16. Recovery of impact signatures in machine structures

    Science.gov (United States)

    McCarthy, D. J.; Lyon, R. H.

    1995-09-01

    Reciprocating machines are difficult to diagnose using traditional frequency domain techniques because they generate predominantly transient vibrations which have a broad frequency content. We have found that transient vibrations, like those generated by valve impacts in a reciprocating compressor, are best analysed in the time-domain. Unfortunately, by the time the vibrations reach the surface of the machine where we can measure them non-invasively, reverberation and dispersion have disfigured them so that they look nothing like their originating forces. In order to convert them into a useful form, where they can be characterized in terms of timing and strength on a cycle-by-cycle basis, the vibration signal can be compressed by filtering it with the inverse of the structural transfer function. This is a straightforward process if the exact transfer function is known; however, in practice we expect to have simply a 'typical' transfer function from a nominally identical machine. Additional transfer function variability results from changes in machine operating conditions such as temperature and load. The inverse-filtering process can be made robust to transfer function variability through a combination of cepstral-smoothing and minimum-phase processing. In addition, if a cepstral comb window is incorporated into the signal processing scheme, multiple impact signatures can be removed.

  17. Food habits of California Sea Lions (Zalophus californianus) and their impact on Salmonid Fisheries in Monterey Bay, California

    OpenAIRE

    Weise, Michael, J.; Harvey, James

    1999-01-01

    In the ocean commercial troll and recreational salmon fishery in Monterey Bay California, California sea lions (Zalophus califomianus) will swim near or follow fishing boats and will depredate fish once hooked. The objectives of the study were to determine the percentage of salmon taken by pinnipeds in commercial and recreational fisheries, identify relative importance of prey items seasonally consumed by sea lions, and determine the proportion of salmonids in the sea lion diet on a seasonal ...

  18. IMPACT OF NEUTRON AND GAMMA RADIATION ON THE DESIGN OF DIAGNOSTICS AND OTHER TARGET-BAY SYSTEMS

    International Nuclear Information System (INIS)

    The design of a wide range of components in and near the target bay of the National Ignition Facility (NIF) must allow for significant radiation from neutrons and gammas. Detailed 3D Monte Carlo simulations are critical to determine neutron and gamma fluxes for all target-bay components to allow optimization of location and auxiliary shielding. Demonstration of ignition poses unique challenges because of the large range (∼3 orders of magnitude) in the yield for any given attempt at ignition. Some diagnostics will provide data independent of yield, while others will provide data for lower yields and only survive high yields with little or no damage. In addition, for a given yield there is a more than 10 orders of magnitude range in neutron and gamma fluxes depending on location in the facility. For example, sensitive components in the diagnostic mezzanines and switchyards require auxiliary shielding for high-yield shots even though they are greater than 17 meters from target chamber center (TCC) and shielded by the 2 m-thick target-bay wall. In contrast, there are components 0.2 to 2 m from TCC with little or no shielding. For these components, particular attention is being made to use low-activation material because of the extremely high neutron loading levels. Many of the components closest to target center are designed to be single use to reduce worker dose from having to refurbish highly activated components. The cryogenic target positioner is an example where activation and ease of component replacement is an important part of the design. We are developing a design process for all target-bay systems that will assure reliable operation for the full range of planned yields

  19. Impact of neutron and gamma radiation on the design of NIF diagnostics and target-bay systems

    International Nuclear Information System (INIS)

    The design of a wide range of components in and near the target bay of the National Ignition Facility (NIF) must allow for significant radiation from neutrons and gammas. Detailed 3-dimensional Monte Carlo simulations are critical to determine neutron and gamma fluxes for all target-bay components to allow optimization of location and auxiliary shielding. Demonstration of ignition poses unique challenges because of the large range (about 3 orders of magnitude) in the yield for any given attempt at ignition. Some diagnostics will provide data independent of yield, while others will provide data for lower yields and only survive high yields with little or no damage. In addition, for a given yield there is a more than 10 orders of magnitude range in neutron and gamma fluxes depending on location in the facility. For example, sensitive components in the diagnostic mezzanines and switchyards require auxiliary shielding for high-yield shots even though they are greater than 17 meters from target chamber center (TCC) and shielded by the 2 m-thick target-bay wall. In contrast, there are components 0.2 to 2 m from TCC with little or no shielding. For these components, particular attention is being made to use low-activation material because of the extremely high neutron loading levels. Many of the components closest to target center are designed to be single use to reduce worker dose from having to refurbish highly activated components. The cryogenic target positioner is an example where activation and ease of component replacement is an important part of the design. We are developing a design process for all target-bay systems that will assure reliable operation for the full range of planned yields. (authors)

  20. Impact of Environmental Policies on the Adoption of Animal Waste Management Practices in the Chesapeake Bay Watershed

    OpenAIRE

    Savage, Jeff; Ribaudo, Marc

    2012-01-01

    We use data from the ERS-NASS ARMS surveys to compare the use of best management practices on poultry and livestock farms inside the watershed and outside the watershed. Animal operations within the Chesapeake Bay States were found to be adopting some important manure management practices at a greater rate than operations outside the watershed. Adoption was taking place before the implementation of the TMDL, indicating that farmers may have been acting in response to building public pressure ...

  1. Ocean currents structuring the mesozooplankton in the Gulf of Mannar and the Palk Bay, southeast coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jagadeesan, L.; Jyothibabu, R.; Anjusha, A.; Mohan, A.P.; Madhu, N.V.; Muraleedharan, K.R.; Sudheesh, K.

    -metric Multidimensional Scaling (NMDS) and Agglomerative Hierarchical Cluster Analysis (AHCA) on Bray-Curtis copepod similarity clearly estranged the Gulf of Mannar and the Palk Bay waters during the Spring Intermonsoon, and the Northeast Monsoon, attributable...

  2. A study on the structure of the convective atmosphere over the Bay of Bengal during BOBMEX-99

    Indian Academy of Sciences (India)

    U C Mohanty; N V Sam; S Das; A N V Satyanarayana

    2003-06-01

    Convective activity is one of the major processes in the atmosphere influencing the local and large scale weather in the tropics. The latent heat released by the cumulus cloud is known to drive monsoon circulation, which on the other hand supplies the moisture that maintains the cumulus clouds. An investigation is carried out on the convective structure of the atmosphere during active and suppressed periods of convection using data sets obtained from the Bay of Bengal and Monsoon Experiment (BOBMEX). The cumulus convection though being a small-scale phenomenon, still influences its embedding environment by interaction through various scales. This study shows the variation in the kinematic and convective parameters during the transition from suppressed to active periods of convection. Convergence in the lower levels and strong upward vertical velocity, significant during active convection are associated with the formation of monsoon depressions. The apparent heat source due to latent heat release and the vertical transport of the eddy heat by cumulus convection, and the apparent moisture sink due to net condensation and vertical divergence of the eddy transport of moisture, are estimated through residuals of the thermodynamic equation and examined in relation to monsoon activity during BOBMEX.

  3. Phytoplankton community structure in local water types at a coastal site in north-western Bay of Bengal.

    Science.gov (United States)

    Baliarsingh, S K; Srichandan, Suchismita; Lotliker, Aneesh A; Sahu, K C; Srinivasa Kumar, T

    2016-07-01

    A comprehensive analysis on seasonal distribution of phytoplankton community structure and their interaction with environmental variables was carried out in two local water types (type 1  30 m isobath) at a coastal site in north-western Bay of Bengal. Phytoplankton community was represented by 211 taxa (146 marine, 37 fresh, 2 brackish, 20 marine-fresh, and 6 marine-brackish-fresh) belonging to seven major groups including 45 potential bloom forming and 22 potential toxin producing species. The seasonal variability depicted enrichment of phytoplankton during pre-monsoon in both water types. Total phytoplankton abundance pattern observed with inter-annual shift during monsoon and post-monsoon period at both water types. In both water types, diatom predominance was observed in terms of species richness and abundance comprising of centric (82 sp.) and pennate (58 sp.) forms. Pennate diatoms, Thalassiothrix longissima and Skeletonema costatum preponderated in both the water types. The diatom abundance was higher in type 1 in comparison to type 2. In general, SiO4 found to fuel growth of the dominant phytoplankton group, diatom in both the water types despite comparative lower concentration of other macronutrients in type 2. PMID:27334343

  4. Phytoplankton Community Structure in the Bay of Bandar Khyran, Sea of Oman with Special Reference to Harmful Algae

    Directory of Open Access Journals (Sweden)

    Khalid Al-Hashmi

    2012-10-01

    Full Text Available The abundance and community structure of the net phytoplankton at two locations in Bandar Khyran Bay were investigated for a period of one complete year. The study region hosts diverse assemblages of net phytoplankton and a total of 248 taxa were identified during the present study. The differences in the species composition of the phytoplankton communities at two locations are not significant while a large spatial and seasonal fluctuation of phytoplankton abundance was observed. These fluctuations are apparently driven by temperature, salinity, dissolved oxygen and nutrient concentration. A minimum abundance of 96 cells/L was observed at OUT station during winter while during the same period it was 138 cells/L at IN station. The maximum counts of phytoplankton occurred in August (17 495 cells/L at OUT but the maximum was observed at IN station in October (33 230 cells/L. In general, the dinoflagellates dominated the net phytoplankton during summer when the water temperature was above 28℃ while diatoms dominated during winter when the water temperature was below 26℃. Amongst the 248 taxa, 27 species (4 diatoms, 21 dinoflagellates, 1 cyanobacteria, 1 dictyochophyte could be considered to be toxic or harmful in high concentrations. Blooms of the dinoflagellate, Noctiluca scintillans were observed during the months of January and September. The increase in optimum biological and hydrographic factors play major role in the bloom formation of Noctiluca scintillans and its spatial distribution.

  5. The impact of urban expansion and agricultural legacies on trace metal accumulation in fluvial and lacustrine sediments of the lower Chesapeake Bay basin, USA.

    Science.gov (United States)

    Coxon, T M; Odhiambo, B K; Giancarlo, L C

    2016-10-15

    The progressively declining ecological condition of the Chesapeake Bay is attributed to the influx of contaminants associated with sediment loads supplied by its largest tributaries. The continued urban expansion in the suburbs of Virginia cities, modern agricultural activities in the Shenandoah Valley, the anthropogenic and climate driven changes in fluvial system hydrodynamics and their potential associated impacts on trace metals enrichment in the bay's tributaries necessitate constant environmental monitoring of these important water bodies. Eight (210)Pb and (137)Cs dated sediment cores and seventy two sediment grab samples were used to analyze the spatial and temporal distributions of Al, Ca, Mg, Cr, Cd, As, Se, Pb, Cu, Zn, Mn, and Fe in the waterways of the Virginia portion of the Chesapeake Bay basin. The sediment cores for trace metal historical fluctuation analysis were obtained in lower fluvial-estuarine environments and reservoirs in the upper reaches of the basin. The trace metal profiles revealed high basal enrichment factors (EF) of between 0.05 and 40.24, which are interpreted to represent early nineteenth century agricultural activity and primary resource extraction. Surficial enrichment factors on both cores and surface grab samples ranged from 0.01 (Cu) to 1421 (Cd), with Pb, Cu, Zn, and Cd enrichments a plausible consequence of modern urban expansion and industrial development along major transportation corridors. Contemporary surficial enrichments of As, Se, and Cr also ranged between 0 and 137, with the higher values likely influenced by lithological and atmospheric sources. Pearson correlation analyses suggest mining and agricultural legacies, coupled with aerosol deposition, are responsible for high metal concentrations in western lakes and headwater reaches of fluvial systems, while metal accumulation in estuarine reaches of the major rivers can be attributed to urban effluence and the remobilization of legacy sediments. PMID:27310532

  6. Microbial biogeography of San Francisco Bay sediments

    Science.gov (United States)

    Lee, J. A.; Francis, C. A.

    2014-12-01

    The largest estuary on the west coast of North America, San Francisco Bay is an ecosystem of enormous biodiversity, and also enormous human impact. The benthos has experienced dredging, occupation by invasive species, and over a century of sediment input as a result of hydraulic mining. Although the Bay's great cultural and ecological importance has inspired numerous surveys of the benthic macrofauna, to date there has been almost no investigation of the microbial communities on the Bay floor. An understanding of those microbial communities would contribute significantly to our understanding of both the biogeochemical processes (which are driven by the microbiota) and the physical processes (which contribute to microbial distributions) in the Bay. Here, we present the first broad survey of bacterial and archaeal taxa in the sediments of the San Francisco Bay. We conducted 16S rRNA community sequencing of bacteria and archaea in sediment samples taken bimonthly for one year, from five sites spanning the salinity gradient between Suisun and Central Bay, in order to capture the effect of both spatial and temporal environmental variation on microbial diversity. From the same samples we also conducted deep sequencing of a nitrogen-cycling functional gene, nirS, allowing an assessment of evolutionary diversity at a much finer taxonomic scale within an important and widespread functional group of bacteria. We paired these sequencing projects with extensive geochemical metadata as well as information about macrofaunal distribution. Our data reveal a diversity of distinct biogeographical patterns among different taxa: clades ubiquitous across sites; clades that respond to measurable environmental drivers; and clades that show geographical site-specificity. These community datasets allow us to test the hypothesis that salinity is a major driver of both overall microbial community structure and community structure of the denitrifying bacteria specifically; and to assess

  7. Structuring the PA process: impact on feedback quality

    OpenAIRE

    Gielen, Mario; Dewever, Bram

    2013-01-01

    The present study examines the impact of structuring the peer assessment process in a wiki-based CSCL-environment. Three conditions are involved: a non-structured, a basic structured, and an elaborated structured peer feedback condition. The main aim of this study is to foster insight into the aspect of peer feedback quality by focusing on the impact of the level of structuring and on the implemented measures to assess peer feedback by both peers and instructor.

  8. Spatial and temporal variability of the velocity and hydrographic structure in a weakly stratified system, Broad Sound, Casco Bay, Maine

    Science.gov (United States)

    Dzwonkowski, Brian; Pettigrew, Neal R.; Knapp, Stacy R.

    2015-06-01

    The velocity and hydrographic structure across Broad Sound, a north-south orientated subsystem of Casco Bay, ME that lacks continuous coastal boundaries, were characterized using velocity observations from two moorings in late summer/fall of 2013 and velocity and density observations from a repeat-transect ship survey conducted over a tidal cycle during the same period. At tidal time scales, the system is dominated by a barotropic semidiurnal standing wave with a west to east decrease in tidal amplitude and relatively minimal phase change across the majority of the transect. The stratification (vertical differences of 0.5-1.0 kg m-3) was generally laterally uniform and stronger during the flood phase which is hypothesized to result from stronger offshore stratification. The mean circulation had strong lateral shear with inflow over the deepest point in the bathymetric cross section and eastern slope and outflow over the western slope. There was also vertical shearing of the horizontal velocities with stronger northward (or northward trending) velocities at depth. The depth-averaged subtidal fluctuations were relatively small (˜2-3 cm s-1) and uncorrelated between mooring sites suggesting the vertically uniform current response associated with remote wind forcing is of limited importance. On the other hand, the depth-dependent velocity fluctuations at the subtidal time scale were, in large part (˜36-72%), driven by wind forcing. The net flux ratio, a means of quantifying the relative importance of the vertical and lateral shear in the flow field, was typically ˜0.44 indicating the structure of the local wind response favored vertically sheared flow.

  9. The impact of the 2008-2009 economic recession on acute myocardial infarction occurrences in various socioeconomic areas of Raritan bay Region, New Jersey

    Directory of Open Access Journals (Sweden)

    Yulong Li

    2014-01-01

    Full Text Available Background: Psychosocial stress is one important risk factor for myocardial infarction. Aim: The study was to assess the impact of the 2008-2009 economic recession on myocardial infarction occurrences in different socioeconomic areas of Raritan Bay region, New Jersey. Materials and Methods: The patients, who were treated for acute myocardial infarction from January 2006 to June 2012, were grouped based on the average incomes of their residence districts in the Raritan Bay region. The Spearman Rank Correlation test was used to assess the correlation between the monthly occurrences of myocardial infarction and Dow Jones stock averages, as well as the correlation between the myocardial infarction occurrences and NJ State unemployment rates. Results: Among 1,491 cases that were identified, 990 cases resided in areas with income below the state average and 477 were from areas above the average. After the onset of the recession, the myocardial infarction occurrences trended up in the low-income area group but not in the high-income area group; and this increasing trend is correlated with the rise in NJ State unemployment rates but not with the changes in stock averages. Conclusion: Our findings suggest that unemployment contributed to an increased risk of myocardial infarction among the residents in low socioeconomic areas after the 2008-2009 economic recession.

  10. Differential metallothionein, reduced glutathione and metal levels in Perna perna mussels in two environmentally impacted tropical bays in southeastern Brazil.

    Science.gov (United States)

    Lavradas, Raquel T; Rocha, Rafael C C; Bordon, Isabella C A C; Saint'Pierre, Tatiana D; Godoy, José M; Hauser-Davis, Rachel A

    2016-07-01

    Mussel farming is an important economic activity in Brazil, and these organisms are consumed by the majority of the population in most coastal zones in the country. However, despite the increasing pollution of aquatic ecosystems in Brazil, little is known about the biochemical activity in mussels in response to metal exposure. In this context, the aim of the present study was to investigate metal and metalloid exposure effects in Perna perna mussels, by determining metal levels, the induction of metallothionein (MT) synthesis, and oxidative stress, in the form of reduced glutathione (GSH) in 3 contaminated areas from the Guanabara Bay in comparison to a reference site, Ilha Grande Bay, both in summer and winter. Metal and metalloid concentrations were also compared to Brazilian and international guidelines, to verify potential health risks to human consumers. Mussels from all sampling sites were shown to be improper for human consumption due to metal contamination, including Ilha Grande Bay, which has previously been considered a reference site. Several statistically significant correlations and seasonal differences were observed between MT, GSH and metals and metalloids in both analyzed tissues. A Discriminant Canonical Analysis indicated that the digestive gland is a better bioindicator for environmental contamination by metals and metalloids in this species and offers further proof that MT variations observed are due to metal exposure and not oxidative stress, since GSH influence for both muscle tissue and the digestive glands was non-significant in this analysis. These results show that P. perna mussels are an adequate sentinel species for metal contamination with significant effects on oxidative stress and metal exposure biomarkers. To the best of our knowledge, this is the first study to report metals, metalloids, MT and GSH levels in the muscle tissue of this species. PMID:26994306

  11. The impact of large-scale reclamation on hydro-dynamic environment-A case study of Xinghua Bay

    Science.gov (United States)

    Yu, Jing; Bao, Xianwen; Ding, Yang; Zhang, Wei; Zhou, Lingling

    2015-09-01

    A hydro-dynamic model is established on basis of MIKE21FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. Tidal elevation data was obtained at the six tide gauge stations around the Xinghua Bay, and another six current stations were established to observe the tidal current velocity and direction. Validation shows that the model-simulated tidal elevation and tidal currents agree well with observations made at different stations. Predictions are made according to the reclamation project proposed in the regional marine planning of Hanjiang Industrial Park around the port in Putian City. The variations of hydro-dynamic factors, such as tide, current velocity and direction and tidal influx are obtained, and the adverse effect of reclamation on marine environment is discussed. It is shown that the tidal level inside the Xinghua Bay during high tide decreases after the reclamation project is completed. The tidal currents during flooding tide generally decrease in the southeast of the reclamation region, with the maximum decreasing amplitude reaching 0.44 m s-1. On the other hand, the tidal currents during flooding tide increase around the southeast and southwest corners of the reclamation region. The tidal currents during ebb tide increase around the southeast and southwest corners of the reclamation region, with the maximum increasing amplitude attaining 0.18 m s-1. The results in this paper can give some guidance for the marine environment management and the effective utilization of land in Putian.

  12. Knottin cyclization: impact on structure and dynamics

    Directory of Open Access Journals (Sweden)

    Gracy Jérôme

    2008-12-01

    Full Text Available Abstract Background Present in various species, the knottins (also referred to as inhibitor cystine knots constitute a group of extremely stable miniproteins with a plethora of biological activities. Owing to their small size and their high stability, knottins are considered as excellent leads or scaffolds in drug design. Two knottin families contain macrocyclic compounds, namely the cyclotides and the squash inhibitors. The cyclotide family nearly exclusively contains head-to-tail cyclized members. On the other hand, the squash family predominantly contains linear members. Head-to-tail cyclization is intuitively expected to improve bioactivities by increasing stability and lowering flexibility as well as sensitivity to proteolytic attack. Results In this paper, we report data on solution structure, thermal stability, and flexibility as inferred from NMR experiments and molecular dynamics simulations of a linear squash inhibitor EETI-II, a circular squash inhibitor MCoTI-II, and a linear analog lin-MCoTI. Strikingly, the head-to-tail linker in cyclic MCoTI-II is by far the most flexible region of all three compounds. Moreover, we show that cyclic and linear squash inhibitors do not display large differences in structure or flexibility in standard conditions, raising the question as to why few squash inhibitors have evolved into cyclic compounds. The simulations revealed however that the cyclization increases resistance to high temperatures by limiting structure unfolding. Conclusion In this work, we show that, in contrast to what could have been intuitively expected, cyclization of squash inhibitors does not provide clear stability or flexibility modification. Overall, our results suggest that, for squash inhibitors in standard conditions, the circularization impact might come from incorporation of an additional loop sequence, that can contribute to the miniprotein specificity and affinity, rather than from an increase in conformational rigidity

  13. Impacts of historic morphology and sea level rise on tidal hydrodynamics in a microtidal estuary (Grand Bay, Mississippi)

    Science.gov (United States)

    Passeri, Davina L.; Hagen, Scott C.; Medeiros, Stephen C.; Bilskie, Matthew V.

    2015-12-01

    This study evaluates the geophysical influence of the combined effects of historic sea level rise (SLR) and morphology on tidal hydrodynamics in the Grand Bay estuary, located in the Mississippi Sound. Since 1848, the landscape of the Mississippi Sound has been significantly altered as a result of natural and anthropogenic factors including the migration of the offshore Mississippi-Alabama (MSAL) barrier islands and the construction of navigational channels. As a result, the Grand Bay estuary has undergone extensive erosion resulting in the submergence of its protective barrier island, Grand Batture. A large-domain hydrodynamic model was used to simulate present (circa 2005) and past conditions (circa 1848, 1917, and 1960) with unique sea levels, bathymetry, topography and shorelines representative of each time period. Additionally, a hypothetical scenario was performed in which Grand Batture Island exists under 2005 conditions in order to observe the influence of the island on tidal hydrodynamics within the Grand Bay estuary. Changes in tidal amplitudes from the historic conditions varied. Within the Sound, tidal amplitudes were unaltered due to the open exposed shoreline; however, in semi-enclosed embayments outside of the Sound, tidal amplitudes increased. In addition, harmonic constituent phases were slower historically. The position of the MSAL barrier island inlets influenced tidal currents within the Sound; the westward migration of Petit Bois Island allowed stronger tidal velocities to be centered on the Grand Batture Island. Maximum tidal velocities within the Grand Bay estuary were 5 cm/s faster historically, and reversed from being flood dominant in 1848 to ebb dominant in 2005. If the Grand Batture Island was reconstructed under 2005 conditions, tidal amplitudes and phases would not be altered, indicating that the offshore MSAL barrier islands and SLR have a greater influence on these tidal parameters within the estuary. However, maximum tidal

  14. Assessment of Containment Structures Against Missile Impact Threats

    Institute of Scientific and Technical Information of China (English)

    LI Q M

    2006-01-01

    In order to ensure the highest safety requirements,nuclear power plant structures (the containment structures,the fuel storages and transportation systems) should be assessed against all possible internal and external impact threats.The internal impact threats include kinetic missiles generated by the failure of high pressure vessels and pipes,the failure of high speed rotating machineries and accidental drops.The external impact threats may come from airborne missiles,aircraft impact,explosion blast and fragments.The impact effects of these threats on concrete and steel structures in a nuclear power plant are discussed.Methods and procedures for the impact assessment of nuclear power plants are introduced.Recent studies on penetration and perforation mechanics as well as progresses on dynamic properties of concrete-like materials are presented to increase the understanding of the impact effects on concrete containment structures.

  15. Fine-scale population structure of two anemones (Stichodactyla gigantea and Heteractis magnifica) in Kimbe Bay, Papua New Guinea

    KAUST Repository

    Gatins, Remy

    2014-12-01

    Anemonefish are one of the main groups that have been used over the last decade to empirically measure larval dispersal and connectivity in coral reef populations. A few species of anemones are integral to the life history of these fish, as well as other obligate symbionts, yet the biology and population structure of these anemones remains poorly understood. The aim of this study was to measure the genetic structure of these anemones within and between two reefs in order to assess their reproductive mode and dispersal potential. To do this, we sampled almost exhaustively two anemones species (Stichodactyla gigantea and Heteractis magnifica) at two small islands in Kimbe Bay (Papua New Guinea) separated by approximately 25 km. Both the host anemones and the anemonefish are heavily targeted for the aquarium trade, in addition to the populations being affected by bleaching pressures (Hill and Scott 2012; Hobbs et al. 2013; Saenz- Agudelo et al. 2011; Thomas et al. 2014), therefore understanding their biology is crucial for better management strategies. Panels of microsatellite markers were developed for each species using next generation sequencing tools. Clonality analyses confirm six pairs of identical genotypes for S. gigantea (n=350) and zero for H. magnifica (n=128), indicating presence/absence of asexual reproduction in this region. S. gigantea showed low structure between islands (FST= 0.003, p-value= 0.000), however, even if the majority of the individuals were unrelated (r~0), 81 families that shared 50% of their genetic material formed from two to four members were found. Out of these families, 45% were found with individuals only within Tuare Island, 11% only in Kimbe Island, and 44% were sharing individuals among islands. In comparison, H. magnifica showed no structure (FST= 0.002, p-value= 0.278), mean relatedness indicated the majority of individuals were unrelated, and 31 families were identified. Families again consisted from two to four members and

  16. Application of impact dampers in vibration control of flexible structures

    Science.gov (United States)

    Akl, Fred A.; Butt, Aamir S.

    1995-01-01

    Impact dampers belong to the category of passive vibration devices used to attenuate the vibration of discrete and continuous systems. An impact damper generally consists of a mass which is allowed to travel freely between two defined stops. Under the right conditions, the vibration of the structure to which the impact damper is attached will cause the mass of the impact damper to strike the structure. Previous analytical and experimental research work on the effect of impact dampers in attenuating the vibration of discrete and continuous systems have demonstrated their effectiveness. It has been shown in this study that impact dampers can increase the intrinsic damping of a lightly-damped flexible structure. The test structure consists of a slender flexible beam supported by a pin-type support at one end and supported by a linear helical flexible spring at another location. Sinusoidal excitation spanning the first three natural frequencies was applied in the horizontal plane. The orientation of the excitation and the test structure in the horizontal plane minimizes the effect of gravity on the behavior of the test structure. The excitation was applied using a linear sine sweep technique. The span of the test structure, the mass of the impact damper, the distance of travel, and the location of the impact damper along the span of the test structure were varied. The damping ratio are estimated for sixty test configurations. The results show that the impact damper significantly increases the damping ratio of the test structure. Statistical analysis of the results using the method of multiple linear regression indicates that a reasonable fit has been accomplished. It is concluded that additional experimental analysis of flexible structures in microgravity environment is needed in order to achieve a better understanding of the behavior of impact damper under conditions of microgravity. Numerical solution of the behavior of flexible structures equipped with impact

  17. Distribution and community structure of fish in Obitsu-gawa River Estuary of inner Tokyo Bay, central Japan

    Directory of Open Access Journals (Sweden)

    Joeppette J. Hermosilla

    2012-09-01

    Full Text Available The distribution and community structure of fish in Obitsu-gawa River Estuary of inner TokyoBay, central Japan was studied from May to December 2005 and March to April 2006. A total of 19,006individuals, represented by 25 species and some unidentified species under family Clupeidae, Cyprinidae,Gobiidae, Hemiramphidae, Mugilidae, Platycephidae, Pleuronectidae and Triglidae were collected. FamilyGobiidae had the most number of taxa with 13 genera and 10 species. Greatest fish abundancehappened in August and secondarily in April and May. Species richness was evident in the warmermonths particularly in May (17 taxa, August (21 taxa, September (15 taxa and October (17 taxa.Marine teleosts significantly contributed to the species richness and abundance of fish, whichcorresponded to 52.9% (10,046 individuals of the total catch while the estuarine fishes were the secondmost abundant group with 33.5% (6,372 individuals of the total catch. Species dominance was acoherent feature of this community. The proportional contribution of marine teleosts to the fishcommunity decreased with increase distance upstream while that of estuarine fishes increased withincrease distance upstream. The developmental stages of gobies range from larvae to adult but juvenilesconstitute 77.06% of the total sample. The distribution of developmental stage of estuarine gobies wasinfluenced to a greater extent by variation in monthly water temperature and station or the interaction ofboth. Adult estuarine gobies had the tendency to aggregate in the middle estuary reflecting their hightolerance to a wide range of water salinity inherent in this station but avoided the lower estuary mostlikely due to the predominance of high salinity waters.

  18. Sedimentologic evidence for structural and topographic evolution following the onset of strike slip, E San Francisco Bay area, CA

    Energy Technology Data Exchange (ETDEWEB)

    Buising, A.V. (CSUH, Hayward, CA (United States))

    1992-01-01

    Mid- to Upper Miocene continental (Orinda and Mulholland Fms.) and shallow marine (Neroly Fm.) strata in the Upper San Leandro Reservoir watershed (SLR) area east of San Francisco Bay preserve important information on structural and landscape evolution during the early phases of strike slip along the Pacific-North American plate boundary. The SLR area lies between the Hayward and Calaveras Faults, major strands of the San Andreas Fault system, and is bisected by the NW-striking Cull Creek Fault (CCF). Geologic mapping delineates five completely intercalated lithofacies in the Mulholland Fm. at SLR. The conglomerate-dominated, sandstone-dominated, and interbedded conglomerate, sandstone, and siltstone facies represent fluvial channel and floodplain deposits; the sandstone + mudstone facies represent lacustrine-deltaic and shallow lacustrine deposits; the shale facies records open lacustrine deposition. Sparse unidirectional paleocurrent indicators show southerly and easterly transport west of the CCF and both westerly and easterly transport east of the CCF. Conglomerate-rich and sand-rich facies tracts are juxtaposed along the CCF. Clast assemblages in Mulholland conglomerates include abundant chart, graywacke, blueschist, and vein quartz, suggesting derivation from a Franciscan-dominated source terrane. Clast assemblages in the gradationally underlying and interfingering Neroly Fm. suggest that it shared the same source terrane; this is atypical for the primarily andesitic (Sierra-derived) Neroly. Fluvial deposits are volumetrically dominant in the Mulholland Fm. at SLR; open-lacustrine shales occur in stratigraphically isolated lenses ranging from > 1 km to < 100 m along strike. This suggests numerous small lakes on a broad drainage plain rather than the single large lake envisioned by previous workers.

  19. Measurement of pollution levels of organochlorine and organophosphorus pesticides in water, soil, sediment, and shrimp to identify possible impacts on shrimp production at Jiquilisco Bay.

    Science.gov (United States)

    Nomen, Rosa; Sempere, Julià; Chávez, Francisco; de López, Nelly Amaya; Rovira, Ma Dolores

    2012-09-01

    This study aims to identify levels of several organochlorine and organophosphorus compounds in shrimp-raising areas of coastal El Salvador, to assess potential impacts on shrimp growth and survival that hamper the sustainability of aquaculture in the region. The paper reports the current levels of γ-HCH, 4,4'-DDT, 4,4'-DDE, 4,4'-DDD, endrin, dieldrin, heptachlor, parathion, methyl parathion, and etoprophos in soils (depth 20 cm), sediments (depth 5 cm), shrimp (Penaeus sp.), and water of three rearing ponds and also in the sediment (depth 5 cm) and water surrounding those ponds in Jiquilisco Bay. Sampling was carried out during the dry (January-March) and rainy (June-August) seasons of 2008. The presence of pesticides in the samples of water, shrimp, and sediment at shrimp ponds was not detected in either season; however, in soil samples (depth 20 cm) taken from these ponds, heptachlor, endrin, dieldrin, 4,4'-DDD, and 4,4'-DDT were identified at concentrations below the method limit of quantification (LOQ), and 4,4'-DDE was found in a concentration falling in the range from 3.85 to 19.61 ng/g. In samples of water taken at the bay water intakes to the rearing ponds, we observed dieldrin concentrations in the range between 0.085 ng/mL and 0.182 ng/mL during the dry season. In the samples of sediments taken in the surrounding areas of shrimp ponds, we found-for both seasons-that in 60 % of the samples, 4,4'-DDE was present in concentrations ranging from 3.75 ng/g to 30.97 ng/g. Additionally, in the rainy season, we observed heptachlor in sediment at concentrations below the method quantification limit. It was concluded that organochlorine compounds from pesticides are still present in Jiquilisco Bay, trapped in deep sediment, even though they have been banned since the 1980s. These were not detected in shrimp tissue, surface water, and shallow sediment in rearing ponds, and hence, we do not believe their presence has any major impact on shrimp production in sampled

  20. Distribution and structure of zooplankton communities in the austral summer in the Prydz Bay, Antarctica

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As a structure linking the ecosystem and population, community plays an important role in the marine ecology. Abundance of different species and development stages were used in our classification to the sampling stations with clustering-analysis and multi-dimension scaling, through which three geographic communities were marked out, respectively as following: the Salp community characterized by presence of Salp thompni in the northern area, the Near-shore community by Euphausia crystallorophias in the south and the main ocean community located between the above two communities. Indicator species method was then carried out between every two communities to findout which species or stages differ most. It tells that Rhincalanus gigas, adult cheatognath, late stages of Metridia gerlachei and calyptopis of Euphausiidae are indicators between Salp and neritic communities, between Krill and Salp communities are Salp thompni, adult and larvae of Cheatognath and R. gigas, and the most notable indicator between the Krill and the neritic communities are E. crystallorophias, then nauplii of Euphausiidae and Onceae conifera with less evidence.

  1. The Impact of Structural Genomics: Expectations and Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Chandonia, John-Marc; Brenner, Steven E.

    2005-12-21

    Structural Genomics (SG) projects aim to expand our structural knowledge of biological macromolecules, while lowering the average costs of structure determination. We quantitatively analyzed the novelty, cost, and impact of structures solved by SG centers, and contrast these results with traditional structural biology. The first structure from a protein family is particularly important to reveal the fold and ancient relationships to other proteins. In the last year, approximately half of such structures were solved at a SG center rather than in a traditional laboratory. Furthermore, the cost of solving a structure at the most efficient U.S. center has now dropped to one-quarter the estimated cost of solving a structure by traditional methods. However, top structural biology laboratories are much more efficient than the average, and comparable to SG centers despite working on very challenging structures. Moreover, traditional structural biology papers are cited significantly more often, suggesting greater current impact.

  2. Thermohaline structure and circulation in the upper layers of the southern Bay of Bengal during BOBMEX-Pilot (October — November 1998)

    Indian Academy of Sciences (India)

    V Ramesh Babu; V S N Murty; L V G Rao; C V Prabhu; V Tilvi

    2000-06-01

    Hydrographic data collected on board ORV Sagar Kanya in the southern Bay of Bengal during the BOBMEX-Pilot programme (October - November 1998) have been used to describe the thermohaline structure and circulation in the upper 200 m water column of the study region. The presence of seasonal Inter-Tropical Convergence Zone (ITCZ) over the study area, typically characterized with enhanced cloudiness and flanked by the respective east/northeast winds on its northern part and west/southwest winds on its southern part, has led to net surface heat loss of about 55 W/m2. The sea surface dynamic topography relative to 500 db shows that the upper layer circulation is characterised by a cyclonic gyre encompassing the study area. The eastward flowing Indian Monsoon Current (IMC) between 5° N and 7° N in the south and its northward branching along 87° E up to 13° N appear to feed the cyclonic gyre. The Vessel-Mounted Acoustic Doppler Current Profiler (VM-ADCP) measured currents confirm the presence of the cyclonic gyre in the southern Bay of Bengal during the withdrawing phase of the southwest monsoon from the northern/central parts of the Bay of Bengal.

  3. Impact of a river system on carbon sedimentation and sequestration in Cook's Bay of Lake Simcoe, Ontario

    Science.gov (United States)

    Blodau, Christian; Agethen, Svenja; Spangenberg, Ines; Broder, Tanja; Gimbel, Nicole; Strauss, Harald; Knorr, Klaus-Holger

    2016-04-01

    The influence of sedimentation rates and organic matter quality on carbon sequestration and mineralization at the land-water interface of lakes is not well understood. To study this issue we investigated shallow Cook's Bay of temperate Lake Simcoe in southern Ontario. The elongated bay provides gradients in morphometry, trophic level, and distance to a major tributary as a potential point source of nutrients and terrestrial organic carbon. At five sampling sites of increasing distance to the river outlet the water column was examined during stratification regarding physio-chemical parameters, dissolved organic matter (DOM) characteristics, sedimentation rates and mineralization of settling material and sediments. To quantify actual organic carbon burial, sedimentation rates and mineralization were determined in situ and by diffusive flux modeling. Long-term carbon burial and sedimentation rates were determined using 210Pb dated sediment cores. Organic carbon quality and origin were analyzed in water samples via fluorescence spectroscopy, solid DOM and settling particles via elemental analysis and 13C isotopic data. Results showed that actual and long-term carbon burial were highest at the central sites of the transect (52-63%) and lowest at the profundal sites (0-25%). Current organic carbon deposition was highest near the river outlet (max. 0.3 g C m-2 d-1) and there the settling material reaching the sediments and in the sediments was also most highly decomposable. Total sedimentation rates and organic carbon burial were closely related. Compared to the outer sites, the DOM quality was significantly different at the site closest to the river outlet but already strongly influenced by lacustrine carbon cycling. Permanent organic carbon burial was mainly influenced by sedimentation related to lake morphometry and dependent parameters. The relation between sedimentation and carbon burial rates underlined the importance of oxygen exposure time and burial for

  4. Sound-speed structure and propagational characteristics of a cold core eddy in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Babu, M.T.; Murty, T.V.R.

    An analysis of acoustic characteristics of a cold core eddy in the Bay of Bengal reveals that the eddy introduces in sound-speEd. by about 10 ms-1. The depth of deep sound channel axis beneath eddy remains constant whereas thickness of surface duct...

  5. Hydor-impact, fluid-structure interaction and structural response of modern racing yacht

    OpenAIRE

    Lee, June

    2009-01-01

    In recent years, faster, lighter and bigger are the key issues in a modern racing yacht for extreme performance. As a result, many yachts have experienced various structural failures caused by the hydrodynamic impact or ’hydro-impact’ phenomenon by slamming. The structural failure by hydro-impact originates from the facts that the external hydro-impact load and fluid structure interaction effect is somewhat misled and when applying the load into current structural design, t...

  6. Anthropization in Montevideo Bay during the Holocene

    International Nuclear Information System (INIS)

    This work is about the anthropogenic historic impacts in subtidal environments in Montevideo Bay. The studies carried out in the sediments enable to conclude that the increase of the industrial discharges (nutrients, heavy metals) are the cause of the chemical changes in the sediment of the Montevideo Bay

  7. THE MUTUAL IMPACT OF ORGANIZATIONAL CULTURE AND STRUCTURE

    OpenAIRE

    Janićijević Nebojša

    2013-01-01

    This paper explores the relationship between the structure and culture of an organization. The starting assumption is that organizational structure and organizational culture impact each other, and that there is a causal relationship due to which the agreement of the two components of organization leads to better performance. First, the mechanism through which organizational culture impacts the design of organizational structures and the manner in which org...

  8. Experimental validation of efficient impact simulation methodologies of sandwich structures

    OpenAIRE

    Kärger, Luise; Baaran, Jens; Teßmer, Jan

    2007-01-01

    Aircraft design calls for weight efficient shell constructions. Composite sandwich structures satisfy this demand by the combination of two thin, stiff face sheets and an intermediate lightweight core. Furthermore, the outer face sheet can act as an impact detector while the core provides damping and insulation. Thus, sandwich structures are increasingly aspired for application as fuselage and wing panels. However, impact damage in sandwich structures can provoke a significant strength and st...

  9. Impact and Penetration Simulations for Composite Wing-like Structures

    Science.gov (United States)

    Knight, Norman F.

    1998-01-01

    The goal of this research project was to develop methodologies for the analysis of wing-like structures subjected to impact loadings. Low-speed impact causing either no damage or only minimal damage and high-speed impact causing severe laminate damage and possible penetration of the structure were to be considered during this research effort. To address this goal, an assessment of current analytical tools for impact analysis was performed. Assessment of the analytical tools for impact and penetration simulations with regard to accuracy, modeling, and damage modeling was considered as well as robustness, efficient, and usage in a wing design environment. Following a qualitative assessment, selected quantitative evaluations will be performed using the leading simulation tools. Based on this assessment, future research thrusts for impact and penetration simulation of composite wing-like structures were identified.

  10. Application of seismic interferometry to an exploration of subsurface structure by using microtremors. Estimation of deep ground structures in the Wakasa bay region

    International Nuclear Information System (INIS)

    We carried out continuous measurements of microtremors to synthesize Green's function based on seismic interferometry in order to estimate deep subsurface structures of the Ohshima peninsula (OSM) and the Otomi peninsula (OTM) in the Wakasa bay region. Using more than 80 days of data, dispersive waveforms in the cross correlations were identified as a Green's function based on seismic interferometry. Rayleigh-wave phase velocities at OSM and OTM were estimated by two different method using microtremors: first, by analyzing microtremor array data, and second, by applying the f-k spectral analysis to synthesized Green's functions derived from cross-correlation with a common observation station. Relatively longer period of phase velocities were estimated by the f-k spectral analysis using the synthesized Green's functions with a common observation station. This suggests that the synthesized Green's functions from seismic interferometry can provide a valuable data for phase velocity inversion to estimate a deep subsurface structure. By identifying deep subsurface structures at OSM and OTM based on an inversion of phase velocity from both methods, the depth of S wave velocity of about 3.5 km/s, considered as a top of seismogenic layer, were determined to be 3.8 - 4.0 km at OSM and 4.4 - 4.6 km at OTM, respectively. Love- and Rayleigh-wave group velocities were estimated from the multiple filtering analysis of the synthesized Green's functions. From the comparison of observed surface wave group velocities and theoretical group velocities of OSM and OTM, we demonstrated that the observed group velocities were in good agreement with the average of theoretical group velocities calculated by identified deep subsurface structures at OSM and OTM. It is suggested that the deep subsurface structure of the shallow sea region between two peninsulas is continuous structure from OSM to OTM and that Love- and Rayleigh-wave group velocities using

  11. Biogeochemical redox cycling of arsenic in mine-impacted lake sediments and co-existing pore waters near Giant Mine, Yellowknife Bay, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, C.F. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Jamieson, H.E., E-mail: jamieson@geol.queensu.ca [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Kyser, T.K. [Queen' s University, Department of Geological Sciences and Geological Engineering, Kingston, K7L 3N6 (Canada); Praharaj, T.; Fortin, D. [University of Ottawa, Department of Earth Sciences, Ottawa, K1A 3N5 (Canada)

    2010-02-15

    Lacustrine sediments, submerged tailings, and their pore waters have been collected at several sites in Yellowknife Bay, Great Slave Lake, Canada, in order to investigate the biogeochemical controls on the remobilization of As from mining-impacted materials under different depositional conditions. Radiometric dating confirms that a mid-core enrichment of Pb, Zn, Cu and Sb corresponds to the opening of a large Au mine 60 a ago. This was evident even in a relatively remote site. Arsenic was enriched at mid-core, coincident with mining activity, but clearly exhibited post-depositional mobility, migrating upwards towards the sediment water interface (SWI) as well as down-core. Deep-water (15 m) Yellowknife Bay sediments that contain buried mine waste are suboxic, relatively organic-rich and abundant in microbes with As in pore waters and sediments reaching 585 {mu}g/L and 1310 mg/kg, respectively. Late summer pore waters show equal proportions of As(III) and As(V) (16-415 {mu}g/L) whereas late winter pore waters are dominated by As(III) (284-947 {mu}g/L). This can be explained by As(III) desorption mechanisms associated with the conversion of FeS to FeS{sub 2} and the reduction of As(V) to As(III) through the oxidation of dissolved sulfide, both microbially-mediated processes. Processes affecting As cycling involve the attenuating efficiency of the oxic zone at the SWI, sediment redox heterogeneity and the reductive dissolution of Fe(hydr)oxides by labile organic matter, temporarily and spatially variable.

  12. Effects of a nuclear power plant thermal discharge on habitat complexity and fish community structure in Ilha Grande Bay, Brazil.

    Science.gov (United States)

    Teixeira, Tatiana Pires; Neves, Leonardo Mitrano; Araújo, Francisco Gerson

    2009-10-01

    Fish communities and habitat structures were evaluated by underwater visual censuses a rocky location impacted by thermal discharge (I) and at two control locations, one in a Sargassum bed (C1) and the other in a rocky shore with higher structural complexity (C2). Habitat indicators and fish communities exhibited significant differences between the impacted and control locations, with the impacted one showing a significant decrease in fish species richness and diversity, as well as a decrease in benthic cover. At the I location, only 13 fish species were described, and the average water temperature was 32+/-0.4 degrees C, compared with 44 species at C1 (25.9+/-0.3 degrees C) and 33 species at C2 (24.6+/-0.2 degrees C). Significant differences in fish communities among locations were found by ANOSIM with Eucinostomus argenteus, Mugil sp. and Haemulon steindachneri typical of location I, while Abudefduf saxatilis, Stegastes fuscus and Malacoctenus delalandi were typical of the control locations. Our study shows that thermal pollution alters benthic cover and influences fish assemblages by altering composition and decreasing richness. PMID:19573906

  13. The two Suvasvesi impact structures, Finland: Argon isotopic evidence for a "false" impact crater doublet

    Science.gov (United States)

    Schmieder, Martin; Schwarz, Winfried H.; Trieloff, Mario; Buchner, Elmar; Hopp, Jens; Tohver, Eric; Pesonen, Lauri J.; Lehtinen, Martti; Moilanen, Jarmo; Werner, Stephanie C.; Öhman, Teemu

    2016-05-01

    The two neighboring Suvasvesi North and South impact structures in central-east Finland have been discussed as a possible impact crater doublet produced by the impact of a binary asteroid. This study presents 40Ar/39Ar geochronologic data for impact melt rocks recovered from the drilling into the center of the Suvasvesi North impact structure and melt rock from glacially transported boulders linked to Suvasvesi South. 40Ar/39Ar step-heating analysis yielded two essentially flat age spectra indicating a Late Cretaceous age of ~85 Ma for the Suvasvesi North melt rock, whereas the Suvasvesi South melt sample gave a Neoproterozoic minimum (alteration) age of ~710 Ma. Although the statistical likelihood for two independent meteorite strikes in close proximity to each other is rather low, the remarkable difference in 40Ar/39Ar ages of >600 Myr for the two Suvasvesi impact melt samples is interpreted as evidence for two temporally separate, but geographically closely spaced, impacts into the Fennoscandian Shield. The Suvasvesi North and South impact structures are, thus, interpreted as a "false" crater doublet, similar to the larger East and West Clearwater Lake impact structures in Québec, Canada, recently shown to be unrelated. Our findings have implications for the reliable recognition of impact crater doublets and the apparent rate of binary asteroid impacts on Earth and other planetary bodies in the inner solar system.

  14. Three-dimensional crustal structure influences on wave propagation and generation of strong ground motion in the greater San Francisco Bay region

    Science.gov (United States)

    Stidham, Christiane Wilson

    Recent development of three-dimensional finite-difference codes allows simulation of earthquakes using realistic three-dimensional earth models. These and other developments have shifted emphasis in seismology from earthquake prediction to estimation of location and magnitude of damage in future earthquakes. The accurate calculation of ground motions for future large earthquakes depends upon detailed knowledge of three-dimensional (3D) geologic structure and the earthquake source process, as well as sufficient computational resources. Knowledge of subsurface geologic structure in the San Francisco Bay Area is quite good relative to many areas, and this knowledge has been incorporated into a 3D velocity model of the Bay Area. With access to a 3D finite-difference code (E3D) developed by Shawn Larsen at Lawrence Livermore National Laboratory and use of super-computing resources at Livermore, we are able to complete calculations for simulations of a number of San Francisco Bay Area earthquakes. These include a small 1993 Rodgers Creek event recorded at Berkeley Seismological Laboratory, the 1989 Loma Prieta event recorded on the U.S. Geological Survey and Calif. Div. of Mines and Geology network of strong motion stations, and a number of small South Bay events (including the 8/12/98 San Juan Bautista EQ) recorded on a temporary USGS/UCB/PASSCAL Santa Clara array. In each of these cases, comparison of synthetic results (synthetic seismograms and plots of maximum horizontal ground velocity) from E3D to recorded data from the event gives an excellent opportunity to both judge the usefulness and the constraints necessary in using finite-difference modeling and the validity of the velocity model as it is now constructed. Results show that 3D finite-difference modeling produces waveforms that are often quite comparable to recorded data, and that fit the data considerably better than synthetics waveforms derived with a 1D velocity model. It is also possible to explore the

  15. Seasonal pattern and community structure of fishes in the shallow tidal creek of Obitsu-gawa River Estuary of inner Tokyo Bay, central Japan

    Directory of Open Access Journals (Sweden)

    Masato Moteki

    2012-12-01

    Full Text Available Seasonal pattern and the community structure of fishes in the shallow tidal creek of ObitsugawaRiver Estuary of inner Tokyo Bay was studied for one year. Family Gobiidae corresponded to 98%of the total catch. Dominant species were Gymnogobius uchidai, Gymnogobius macrognathos,Gymnogobius breunigii, Eutaeniichthys gilli, Pseudogobius masago and Favonigobius gymnauchen.Stepwise modelling in canonical correspondence analysis indicated that season (p=0.02 best explainedthe variation in abundance of fish in this shallow habitat. There was a difference in fish communitybetween spring and summer while only a small difference was observed between summer and autumn aswell as winter and autumn. Species dominance was an inherent property of the tidal creek fishcommunity particularly in spring because of the remarkable abundance of G. uchidai. However, the fishcommunity had the tendency to become proportionately even as the season progresses from spring towinter. The occurrence of a particular life history stage generally showed a strong association with monthand water temperature. Adults substantially contributed to the population size structure of P. masagoand G. uchidai while juvenile 2 for G. breunigii and E. gilli . Larvae significantly contributed to thepopulation size structure of F. gymnauchen while juvenile 1 and juvenile 2 for G. macrognathos. Thecurrent study indicated that natural shallow habitat within a highly urbanized metropolitan area in innerTokyo Bay can serve as a habitat for fishes and the prevalence of certain life history stages of estuarinespecies indicated the importance of the said habitat at certain part of their life history.

  16. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    Directory of Open Access Journals (Sweden)

    M. L. Kirwan

    2013-03-01

    Full Text Available The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  17. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    Directory of Open Access Journals (Sweden)

    M. L. Kirwan

    2012-10-01

    Full Text Available The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  18. Structured ion impact: Doubly differential cross sections

    International Nuclear Information System (INIS)

    The electron emission in coincidence with a projectile that has been ionized has been measured, thus making it possible to separate and identify electrons resulting from these various mechanisms. In 1985, coincidence doubly differential cross sections were measured for 400 to 750 keV/atomic mass unit (amu) He+ impact on He, Ne, Ar, Kr, and H2O. Cross sections were measured for selected angles and for electron energies ranging from 10 to 1000 eV. Because of the coincidence mode of measurement, the total electron emission was subdivided into its target emission and its projectile emission components. The most interesting findings were that target ionization does not account for the electron emission spectrum at lower electron energies. A sizable percentage of these low-energy electrons were shown to originate as a result of simultaneous projectile/target ionizations. Similar features were observed for all targets and impact energies that were studied

  19. Fatigue behaviour of impacted composite structures

    OpenAIRE

    Garnier, Christian; Pastor, Marie-Laetitia; Lorrain, Bernard; Pantalé, Olivier

    2013-01-01

    International audience The aim of this study was to compare the mechanical behavior of different impact-damaged composite materials. Three composite materials were realized using the Liquid Resin Infusion process (LRI) accord- ing to three different cycles of polymerization. Thus the temperature of the glass transition of the resin was controlled and the influence of this parameter was then determined. In accordance with the aeronautical use of composite materials, the plates were subjecte...

  20. Impact of climate change on building structures

    Czech Academy of Sciences Publication Activity Database

    Drdácký, Miloš

    Bari : EDIPUGLIA, 2010 - (Lefebre, R.; Sabbioni, C.), s. 139-153 ISBN 978-88-7228-601-2 R&D Projects: GA ČR(CZ) GA103/09/2067 Grant ostatní: evropská komise(XE) 6th FP EC CHEF -044251 Institutional research plan: CEZ:AV0Z20710524 Keywords : climate change impact * weathering * vulnerability of buildings Subject RIV: AL - Art, Architecture, Cultural Heritage

  1. Structural design for aircraft impact loading

    International Nuclear Information System (INIS)

    The distribution of military aircraft and proximity to commercial air routes requires the analysis of aircraft impact effect on nuclear power plant facilities in Europe. The 'hardened-building' approach has led to the consideration of severe shock and vibration caused by the aircraft impact and development of corresponding floor response spectra for component design. The reactor auxiliary system building allows a more defensive alternate in the form of a partially softened design. In this approach the equipment layout is arranged such that equipment performing either safety functions or having the potential for significant release of radioctivity (upon destruction) is located in the central area of the plant and is enclosed in thick concrete walls for shielding and protection purposes. The non-safety class equipment is arranged in the area peripheral to the hardened central area and enclosed in thin concrete walls. Since the kinetic energy of the impacting aircraft is absorbed by the collapsed thin walls and ceilings, the vibrational effect on the safety class equipment is drastically reduced. In order to achieve the objective of absorbing high kinetic energy and yet reduce the shock and vibration effects, the softened exterior walls require low resistance and high ductility. In order not to increase the construction cost, and yet to assure the safety of the plant, some dynamic tests of conventionally reinforced slabs have to be performed all the way to collapse. These calculations have assumptions of achieving the maximum velocity instantaneously after impact, and take into account the kinetic energy in the broken wall. Nonlinear equations of motion are also formulated and solved. The results indicate that the phantom jet would go through the first wall. The second wall would stop the jet, but would sustain some permanent deformation and damage

  2. Reproduction and structure of the population of the Chaetognath Parasagitta friderici in Guanabara Bay (Brazil) based on short term sampling

    OpenAIRE

    Fabiana Mendes; Gisela M Figueiredo; Jean L. Valentin

    2012-01-01

    The aim of this study was to describe the total density, densities of developmental stages and the reproduction period of Parasagitta friderici. Weekly samples were collected at one station in the channel of Guanabara Bay, Rio de Janeiro, during one year. Three vertical hauls were made for each sample, and P. friderici was separated, the developmental stages were identified, and body length (BL), ovary length (OL) and seminal vesicle width (SVW) were measured. Throughout the year P. friderici...

  3. Low velocity blunt impacts on composite aircraft structures

    OpenAIRE

    Whisler, Daniel A.

    2009-01-01

    As composites are increasingly used for primary structures in commercial aircrafts, it is necessary to understand damage initiation for composites subject to low velocity impacts from service conditions, maintenance, and other ground equipment mishaps. In particular, collisions with ground vehicles can present a wide area, blunt impact. Therefore, the effects of bluntness of an impactor are of interest as this is related to both the external visual detectability of an impact event, as well as...

  4. Comparative study of the hydrochemical regime in the Gelendzhik and Golubaya Bays, northeastern Black Sea

    Science.gov (United States)

    Kostyleva, A.; Chasovnikov, V.; Chjoo, V.; Menshikova, N.; Kuprikova, N.

    2009-04-01

    The goal of this work was to study the hydrochemical regime in the coastal waters of the northeastern Black Sea. The observations were performed in influenced by significant anthropogenic stress Gelendzhik Bay and at the open coast region (Golubaya Bay). A sampling program has been initiated by the Southern Branch of Shirshov Institute of Oceanology, RAS, (SB SIO RAS) on a weekly basis at the shore line area of «Chernomorets» beach (Gelendzhik Bay) and from the head of pier in the Golubaya Bay. Studies were carried out during a period from January 2001 to December 2008. List of measured parameters includes following: temperature, salinity, dissolved oxygen, biological oxygen demand (BOD), pH, alkalinity, phosphate, organic phosphorus, silicates, nitrates, nitrites, ammonia, urea, organic nitrogen, oil products. The Gelendzhik bay in its different parts is characterized with strong variability of concentrations of hydrochemical parameters. Above all, it relates to complex structure caused by wind impact. Parts of the bay filled with nearshore and sea waters are legibly differ from each other. The bay itself is rather isolated from the open sea, and its liability to man's impact leads to forming of next features of its seasonal variability of physical-chemical state: • On the base of Si/P and Si/N ratios analysis it was shown that the Gelendzhik Bay waters are significantly enriched with nitrogen and phosphorus compounds. • Unlike the Golubaya bay, phosphates are always present in the water of the Gelendzhik Bay and development of photosynthesis is not limited with nutrients. It may lead to processes of intensive eutrophication. • The oxygen saturation in the Gelendzhik Bay periodically descend lower than 80% during the summer period. That means, that even the Bay's surface layer formally corresponds to the hypoxic conditions that testify to the degradation of the ecosystem there. The conclusions obtained during our studies testify that the pollution from

  5. Impact of the structural changes on the nuclear safety

    International Nuclear Information System (INIS)

    In this presentation author deals with impact of the structural changes (privatization of the Slovenske Elektrarne, a.s.) and new Atomic law (541/2004 Coll. Laws) on the nuclear safety in the Slovak Republic.

  6. Ouarkziz Impact Structure, Algeria: Preliminary Petrographic and Geochemical Studies

    Science.gov (United States)

    Sahoui, R.; Belhai, D.

    2015-07-01

    Ouarkziz impact crater in Algeria is set in Namurian lower limestone and marls with gypsum. We present here preliminary petrographic and geochemical studies of the rocks and breccias forming the rings ans the central area of the structure.

  7. The Impact of Capital Structure on Firms’ Performance in Nigeria

    OpenAIRE

    Ogebe, Patrick; Ogebe, Joseph; Alewi, Kemi

    2013-01-01

    This study seeks to investigate the impact of capital structure on firm performance in Nigeria from 2000 to 2010. We considered the impact of some key macroeconomic variables (gross domestic product and inflation) on firm performance. The traditional theory of capital structure was employed to determine the significance of leverage and macroeconomic variables on firm’s performance. The study makes a comparative analysis of the selected firms which are classified into highly and lowly gear...

  8. Structural impact detection with vibro-haptic interfaces

    Science.gov (United States)

    Jung, Hwee-Kwon; Park, Gyuhae; Todd, Michael D.

    2016-07-01

    This paper presents a new sensing paradigm for structural impact detection using vibro-haptic interfaces. The goal of this study is to allow humans to ‘feel’ structural responses (impact, shape changes, and damage) and eventually determine health conditions of a structure. The target applications for this study are aerospace structures, in particular, airplane wings. Both hardware and software components are developed to realize the vibro-haptic-based impact detection system. First, L-shape piezoelectric sensor arrays are deployed to measure the acoustic emission data generated by impacts on a wing. Unique haptic signals are then generated by processing the measured acoustic emission data. These haptic signals are wirelessly transmitted to human arms, and with vibro-haptic interface, human pilots could identify impact location, intensity and possibility of subsequent damage initiation. With the haptic interface, the experimental results demonstrate that human could correctly identify such events, while reducing false indications on structural conditions by capitalizing on human’s classification capability. Several important aspects of this study, including development of haptic interfaces, design of optimal human training strategies, and extension of the haptic capability into structural impact detection are summarized in this paper.

  9. Study on the marine sedimentary environment evolution of the southern Laizhou Bay under the impact of port projects

    Science.gov (United States)

    Liu, Xiao; Liu, Jie; Feng, Xiuli

    2016-06-01

    The southern Laizhou Bay is mainly composed of silt-sandy coasts with diverse landforms, and its marine hydrodynamic environment is sensitive to human activities. Marine hydrodynamic and sedimentary environments of the study area have changed under the influence of large-scale port projects in recent years. In this paper, the evolution of hydrodynamic environment, deposition rate, and geochemical characteristics were studied based on sediment grain size, element analysis and 210Pb dating of two cores, in order to analyze the influence of Weifang Port on marine environmental evolution, and provide theoretical and practical basis for protecting marine environment in developing marine resources reasonably. Results showed that sediments of the two cores were relatively coarser and mainly composed of silty sand. Sediments above 230 cm in core WF1 and 218 cm in core WF2 were deposited since 1855 when the Yellow River appeared to deposit its sediments within the modern active delta, and the average deposition rate was between 0.3 and 0.5 cm a-1. Implement of Weifang Port projects in 1997 and 2007 created great influence on the sedimentary environment evolution in the surrounding waters, and the deposition rate was significantly increased. The average annual deposition rates were 5.1 cm and 3.5 cm in WF1 and WF2 respectively between 1997 and 2007. Content of heavy metals in sediments showed no obvious change in the vertical, indicating that the heavy metals were less affected by human activity and there was no significant accumulation of such metals in the study area.

  10. Governance structures impact on eHealth

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    2015-01-01

    Background National eHealth implementation efforts need to move beyond the scope of making technology the primary focus and instead consider the broader spectrum of influences that can either hinder or facilitate eHealth adoption such as governance structures and policies. In this study, Denmark...

  11. Impact of period and timescale of FDDA analysis nudging on the numerical simulation of tropical cyclones in the Bay of Bengal

    KAUST Repository

    Viswanadhapalli, Yesubabu

    2014-06-22

    In this study, the impact of four-dimensional data assimilation (FDDA) analysis nudging is examined on the prediction of tropical cyclones (TC) in the Bay of Bengal to determine the optimum period and timescale of nudging. Six TCs (SIDR: November 13–16, 2007; NARGIS: April 29–May 02, 2008; NISHA: November 25–28, 2008; AILA: May 23–26, 2009; LAILA: May 18–21, 2010; JAL: November 04–07, 2010) were simulated with a doubly nested Weather Research and Forecasting (WRF) model with a horizontal resolution of 9 km in the inner domain. In the control run for each cyclone, the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) analysis and forecasts at 0.5_ resolution are used for initial and boundary conditions. In the FDDA experiments available surface, upper air observations obtained from NCEP Atmospheric Data Project (ADP) data sets were used for assimilation after merging with the first guess through objective analysis procedure. Analysis nudging experiments with different nudging periods (6, 12, 18, and 24 h) indicated a period of 18 or 24 h of nudging during the pre-forecast stage provides maximum impact on simulations in terms of minimum track and intensity forecasts. To determine the optimum timescale of nudging, two cyclone cases (NARGIS: April 28–May 02, 2008; NISHA: November 25–28, 2008) were simulated varying the inverse timescales as 1.0e-4 to 5.0e-4 s−1 in steps of 1.0e-4 s−1. A positive impact of assimilation is found on the simulated characteristics with a nudging coefficient of either 3.0e-4 or 4.0e-4 s−1 which corresponds to a timescale of about 1 h for nudging dynamic (u,v) and thermodynamical (t,q) fields.

  12. Study of Similarity Law for Bird Impact on Structure

    Institute of Scientific and Technical Information of China (English)

    Li Yulong; Zhang Yongkang; Xue Pu

    2008-01-01

    With dimensional analysis and similarity theory, the model similarity law of aircraft structures under bird impact load is investi-gated. Numerical calculations by means of nonlinear dynamic software ANSYS/LS-DYNA are conducted on the finite element models constructed with different scaling factors. The influence of strain rate on the model similarity law is found to be dependent on the swain rate sensitivity of materials and scale factors. Specifically, materials that are not sensitive to strain rate obey the model similarity law in the bird impact process. The conclusions obtained are supposed to provide a theoretical basis for the experimental work of bird impact on aircraft structure.

  13. Theoretical study of reinforced concrete structures under missile impact loading

    International Nuclear Information System (INIS)

    A theoretical study of reinforced concrete structure behavior under missile impact loading has been performed. The study was limited to cylindrical geometry and only to nondeformable missiles with a flat front nose. The finite difference Lagrangian code, which is based on crack propagation theory, has been elaborated and verified for experiments with rigid missile impact on reinforced slabs. For the initial time interval after the impact, there is good agreement between theory and experiment, not only for local quantities but also with respect to the structural response of the whole target

  14. Application of native knowledge in EIA: Inuit, eiders and Hudson Bay oil. Les connaissances des autochtones appliquees aux etudes d'impact environnemental: Les Inuit, les eiders et le petrole de la baie d'Hudson

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, D.J.

    1990-09-01

    Environmental baseline data, essential for environmental impact assessment of petroleum development, is scarce or nonexistent for much of the Arctic. It is proposed that environmental assessment in Arctic regions can benefit substantially from Inuit environmental knowledge, in the form of a formal integration of Inuit expertise into the environmental assessment process. To assess the soundness of this proposition, environmental data from Inuit of 3 communities in southeastern Hudson Bay are examined. These data pertain to the biogeography and ecology of the Hudson Bay eider (Somateria mollissima sedentaria), a large seaduck of interest because of its extreme vulnerability to oil pollution. Information on this bird was collected by means of semi-directive interviews with Inuit hunters. This information reveals an extensive knowledge of the dramatic seasonal changes in the distribution and habitat use of the eider, and their winter mortality. The applications of this knowledge to environmental impact assessment is discussed. 16 refs., 5 figs.

  15. Hydrocarbons in the Haughton Impact Structure, Devon Island, Nunavut, Canada

    Science.gov (United States)

    Parnell, J.; Osinski, G. R.; Lee, P.; Baron, M.; Pearson, M. J.; Feely, M.

    2003-01-01

    The occurrence of organic matter in terrestrial impact craters is important to astrobiology, as it may offer insight into possible relationships between impact events and the genesis, distribution and preservation of biologically relevant materials on planets. In particular, the processing and mobilization of preexisting organic material in planetary targets is of interest for studies of pathways to chemical complexity. Observations in old (Palaeozoic, Precambrian) craters indicate that organic carbon can survive large impacts. However, limited exposure and superimposed geological events can make the detailed history of organic matter in old craters difficult to decipher. We present here the first identification of hydrocarbons in the young (23 Ma, Miocene) Haughton impact structure.

  16. Structural Behavior of SC and RC Panels under Impact Loading

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyuk-Kee; Kim, Seung-Eock [Sejong University, Seoul (Korea, Republic of)

    2015-05-15

    NPP structures have been generally constructed using reinforced concrete (RC) structures. In recent studies, however, it has been confirmed that a steel-plate concrete (SC) structures has a much better impact resistance than an RC structure. In this paper, the impact resistance of SC and RC panels is evaluated using the commercial software LS-DYNA. To verify finite element (FE) models, the analysis results for SC and half steel-plate concrete panels under impact loading are compared with the test results conducted in other research. The impact analysis according to the different steel ratios with four different concrete thicknesses is performed in order to compare the impact resistance of SC and RC panels. To compare the impact resistance of SC and RC panels, the impact analysis was performed according to the different steel ratios with four different concrete thicknesses. Based on this study, the following conclusions have been obtained: (1) The rear face steel plate of SC panel plays more important role than the rear rebar of RC panel in preventing perforation. (2) When the perforation failure occurs, RC panel is more effective than SC panel to reduce the velocity of the missile.

  17. Impact of Community Structure on Cascades

    OpenAIRE

    Moharrami, Mehrdad; Subramanian, Vijay; Liu, Mingyan; Lelarge, Marc

    2016-01-01

    The threshold model is widely used to study the propagation of opinions and technologies in social networks. In this model individuals adopt the new behavior based on how many neighbors have already chosen it. We study cascades under the threshold model on sparse random graphs with community structure to see whether the existence of communities affects the number of individuals who finally adopt the new behavior. Specifically, we consider the permanent adoption model where nodes that have ado...

  18. Suppressing grazing chaos in impacting system by structural nonlinearity

    International Nuclear Information System (INIS)

    In this note we investigate the influence of structural nonlinearity of a simple cantilever beam impacting system on its dynamic responses close to grazing incidence by a means of numerical simulation. To obtain a clear picture of this effect we considered two systems exhibiting impacting motion, where the primary stiffness is either linear (piecewise linear system) or nonlinear (piecewise nonlinear system). Two systems were studied by constructing bifurcation diagrams, basins of attractions, Lyapunov exponents and parameter plots. In our analysis we focused on the grazing transitions from no impact to impact motion. We observed that the dynamic responses of these two similar systems are qualitatively different around the grazing transitions. For the piecewise linear system, we identified on the parameter space a considerable region with chaotic behaviour, while for the piecewise nonlinear system we found just periodic attractors. We postulate that the structural nonlinearity of the cantilever impacting beam suppresses chaos near grazing

  19. Suppressing grazing chaos in impacting system by structural nonlinearity

    Energy Technology Data Exchange (ETDEWEB)

    Souza, S.L.T. de [Centre for Applied Dynamics Research, Department of Engineering, Fraser Noble Building, King' s College, University of Aberdeen AB24 3UE, Scotland (United Kingdom); Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Wiercigroch, M. [Centre for Applied Dynamics Research, Department of Engineering, Fraser Noble Building, King' s College, University of Aberdeen AB24 3UE, Scotland (United Kingdom)], E-mail: M.Wiercigroch@abdn.ac.uk; Caldas, I.L. [Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Balthazar, J.M. [Departamento de Estatistica, Matematica Aplicada e Computacional, Instituto de Geociencias e Ciencias Exatas, Universidade Estadual Paulista, C.P. 178, 13500-230 Rio Claro, SP (Brazil)

    2008-11-15

    In this note we investigate the influence of structural nonlinearity of a simple cantilever beam impacting system on its dynamic responses close to grazing incidence by a means of numerical simulation. To obtain a clear picture of this effect we considered two systems exhibiting impacting motion, where the primary stiffness is either linear (piecewise linear system) or nonlinear (piecewise nonlinear system). Two systems were studied by constructing bifurcation diagrams, basins of attractions, Lyapunov exponents and parameter plots. In our analysis we focused on the grazing transitions from no impact to impact motion. We observed that the dynamic responses of these two similar systems are qualitatively different around the grazing transitions. For the piecewise linear system, we identified on the parameter space a considerable region with chaotic behaviour, while for the piecewise nonlinear system we found just periodic attractors. We postulate that the structural nonlinearity of the cantilever impacting beam suppresses chaos near grazing.

  20. Towards a sustainable future in Hudson Bay

    International Nuclear Information System (INIS)

    To date, ca $40-50 billion has been invested in or committed to hydroelectric development on the rivers feeding Hudson Bay. In addition, billions more have been invested in land uses such as forestry and mining within the Hudson Bay drainage basin. However, there has never been a study of the possible impacts on Hudson Bay resulting from this activity. Neither has there been any federal environmental assessment on any of the economic developments that affect Hudson Bay. To fill this gap in knowledge, the Hudson Bay Program was established. The program will not conduct scientific field research but will rather scan the published literature and consult with leading experts in an effort to identify biophysical factors that are likely to be significantly affected by the cumulative influence of hydroelectric and other developments within and outside the region. An annotated bibliography on Hudson Bay has been completed and used to prepare a science overview paper, which will be circulated for comment, revised, and used as the basis for a workshop on cumulative effects in Hudson Bay. Papers will then be commissioned for a second workshop to be held in fall 1993. A unique feature of the program is its integration of traditional ecological knowledge among the Inuit and Cree communities around Hudson Bay with the scientific approach to cumulative impact assessment. One goal of the program is to help these communities bring forward their knowledge in such a way that it can be integrated into the cumulative effects assessment

  1. Evaluation /Scoping of Management plans - Data analysis for support of the impact assessment for the management plan of Bay of Biscay anchovy (COM(2009)399 final) (STECF-14-05)

    OpenAIRE

    Scientific, Technical and Economic Committee for Fisheries (STECF)

    2014-01-01

    The Expert Working Group meeting of the Scientific, Technical and Economic Committee for Fisheries EWG-14-03 on Evaluation/scoping of Management plans. Data analysis for support of the impact assessment for the management plan of Bay of Biscay anchovy (COM(2009)399 final) was held from 10-14 March 2014 in Varese, Italy. The report was reviewed and endorsed by the STECF during its plenary meeting held from 24 to 28 March 2014 in Brussels (Belgium).

  2. Scientific, Technical and Economic Committee for Fisheries (STECF) - Evaluation/scoping of Management plans - Data analysis for support of the impact assessment for the management plan of Bay of Biscay anchovy (COM(2009)399 final). (STECF-14-05)

    OpenAIRE

    2014-01-01

    The Expert Working Group meeting of the Scientific, Technical and Economic Committee for Fisheries EWG-14-03 on Evaluation/scoping of Management plans. Data analysis for support of the impact assessment for the management plan of Bay of Biscay anchovy (COM(2009)399 final) was held from 10-14 March 2014 in Varese, Italy. The report was reviewed and endorsed by the STECF during its plenary meeting held from 24 to 28 March 2014 in Brussels (Belgium).

  3. Analysis and modelization of lightweight structures subjected to impact

    OpenAIRE

    Barbero Pozuelo, Enrique; López-Puente, Jorge

    2008-01-01

    Mechanics of Advanced Materials research group (Department of Continuum Mechanics and Structural Analysis) of the University Carlos III of Madrid (Spain) offers their experience in the analysis and modelization of high and low velocity impact behaviour of composite structures. Their research focuses on both numerical analysis and non-standard experimental methodologies).

  4. Experimental Study of Hypervelocity Impact on Multi-Shock Structure

    Institute of Scientific and Technical Information of China (English)

    张庆明; 陈沿海; 黄风雷

    2004-01-01

    Hypervelocity impact tests on multi-shock shields are carried out in order to develop space structures against space debris impacts. Sheets of LY12 aluminum were used as bumpers. The total thickness of shield structure, which consists of several sheets with various thickness, is 3.0 mm or 2.0 mm. Results of the tests show that the type 0.5 mm+0.5 mm+0.5 mm+0.5 mm is a better choice of spacecraft shield structure.

  5. Community structure and coral status across reef fishing intensity gradients in Palk Bay reef, southeast coast of India.

    Digital Repository Service at National Institute of Oceanography (India)

    Manikandan, B.; Ravindran, J.; Shrinivaasu, S.; Marimuthu, N.; Paramasivam, K.

    Healthy live coral (LC/H), Live coral colonized by turf algae (LC/TA) and Live coral colonized by macro algae (LC/MA). 2.3 Reef fish survey The diversity and the quantity of commercially exploited reef fishes in the Palk bay reef was surveyed through... in MRC, comparatively higher than the sites influenced by reef fishing.. The diversity of corals present in the study sites were summarized in the Table 2. As per the results of Bray-Curtis cluster analysis under paired linkage the study sites were...

  6. Advanced simulation of damage of reinforced concrete structures under impact

    International Nuclear Information System (INIS)

    The efficiency of the discrete element method for studying the fracture of heterogeneous media has been demonstrated, but it is limited by the size of the computational model. A coupling between the discrete element and the finite element methods is proposed to handle the simulation of impacts on large structures. The structure is split into sub-domains in each of which the method of analysis is adapted to optimise the modelling of the structure behaviour under impact. The DEM takes naturally into account the discontinuities and is used to model the media in the impact zone. The remaining structure is modelled by the FEM. Proposed combined DE/FE algorithm is implemented in the Europlexus fast dynamics software and parallelized with MPI formalism. The efficiency of the Europlexus multi-domain MPI parallel version is tested. (authors)

  7. Design formula of reinforced concrete structures against rigid missile impact

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Chihiro; Shirai, Koji; Ohnuma, Hiroshi [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab.

    1995-01-01

    For the design of concrete containment structures built in nuclear power stations in Japan, internal pressure, temperature load and earthquake load have so far been considered as the major types of load that could result from accident. In some foreign countries, impact load caused by collision of missile is taken into consideration for the design of this kind of structures as well. Also in Japan, in the design of the repossessing plants which is now under construction at Shimokita area, air craft crash is taken into account. In this study, in order to establish the design method of concrete structures against impact due to collision of missile, the impact tests have been carried out using hard missile with the velocity from 4.0m/s to 250m/s. Based on these results, we proposed the design method of reinforced concrete structure against the collision of hard missile. (author).

  8. The eastern Baffin Bay. A preliminary strategic environmental impact assessment of hydrocarbon activities in the KANUMAS West area; Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Boertmann, D.; Johansen, K.; Maltha Rasmussen, L.; Schiedek, D.; Ugarte, F.; Mosbech, A.; Frederiksen, M.; Bjerrum, M.

    2009-05-15

    The environmental impacts of exploration activities will mainly be disturbance from activities creating noise such as seismic surveys and drilling. The impacts are expected to be relatively small, local and temporary, because of the intermittent nature of the exploration activities. Furthermore, the season for exploration activities is very short and limited to the few months with light ice conditions (June-October). The activities during development, production and transport are on the other hand long-lasting, and there are several activities which have the potential to cause severe environmental impacts. Careful Health, Safety and Environment (HSE) procedures, application of Best Available Technique (BAT) and Best Environmental Practice (BEP), zero-discharge policy and planning in combination with thorough background studies and application of the Precautionary Principle can mitigate most of these. The environmentally most severe accident would be a large oil spill. This has the potential to impact the marine ecosystem on all levels from primary production to the top predators. Oil spill trajectory modelling was carried out by DMI as a part of this SEIA. In most of the modelled oil spill drift scenarios oil does not reach the coasts, but stays offshore. However, three of the 24 scenarios indicate that under certain conditions, oil may reach shores up to several hundred kilometres from the spill site. (ln)

  9. Uncertainty in model predictions of Vibrio vulnificus response to climate variability and change: a Chesapeake Bay case study.

    Directory of Open Access Journals (Sweden)

    Erin A Urquhart

    Full Text Available The effect that climate change and variability will have on waterborne bacteria is a topic of increasing concern for coastal ecosystems, including the Chesapeake Bay. Surface water temperature trends in the Bay indicate a warming pattern of roughly 0.3-0.4°C per decade over the past 30 years. It is unclear what impact future warming will have on pathogens currently found in the Bay, including Vibrio spp. Using historical environmental data, combined with three different statistical models of Vibrio vulnificus probability, we explore the relationship between environmental change and predicted Vibrio vulnificus presence in the upper Chesapeake Bay. We find that the predicted response of V. vulnificus probability to high temperatures in the Bay differs systematically between models of differing structure. As existing publicly available datasets are inadequate to determine which model structure is most appropriate, the impact of climatic change on the probability of V. vulnificus presence in the Chesapeake Bay remains uncertain. This result points to the challenge of characterizing climate sensitivity of ecological systems in which data are sparse and only statistical models of ecological sensitivity exist.

  10. Uncertainty in Model Predictions of Vibrio Vulnificus Response to Climate Variability and Change: A Chesapeake Bay Case Study

    Science.gov (United States)

    Urquhart, Erin A.; Zaitchik, Benjamin F.; Waugh, Darryn W.; Guikema, Seth D.; Del Castillo, Carlos E.

    2014-01-01

    The effect that climate change and variability will have on waterborne bacteria is a topic of increasing concern for coastal ecosystems, including the Chesapeake Bay. Surface water temperature trends in the Bay indicate a warming pattern of roughly 0.3-0.4 C per decade over the past 30 years. It is unclear what impact future warming will have on pathogens currently found in the Bay, including Vibrio spp. Using historical environmental data, combined with three different statistical models of Vibrio vulnificus probability, we explore the relationship between environmental change and predicted Vibrio vulnificus presence in the upper Chesapeake Bay. We find that the predicted response of V. vulnificus probability to high temperatures in the Bay differs systematically between models of differing structure. As existing publicly available datasets are inadequate to determine which model structure is most appropriate, the impact of climatic change on the probability of V. vulnificus presence in the Chesapeake Bay remains uncertain. This result points to the challenge of characterizing climate sensitivity of ecological systems in which data are sparse and only statistical models of ecological sensitivity exist.

  11. Fluid Structure Interaction Effects on Composites Under Low Velocity Impact

    OpenAIRE

    Conner, Ryan P.

    2012-01-01

    In this study composite materials were tested in different fluid environments to determine the role of Fluid Structure Interaction with these composites under a lower velocity impact. The purpose of this research is to develop a better understanding of possible marine applications of composite materials. This was done using a low velocity impact machine and two composite types. The first composite is made from a multi-ply symmetrical plain weave 6 oz. E-glass skin. The test area of the compos...

  12. Origin of the Vredefort structure, South Africa: Impact model

    Science.gov (United States)

    Therriault, A. M.; Reid, A. M.; Reimold, W. U.

    1993-01-01

    A model is presented for the evolution of the Vredefort structure, based on reasoned constraints on the original size of the Vredefort structure from observational data and comparison with other terrestrial impact craters. The models for complex craters (ring and multi-ring basins) of Croft, Grieve, and co-workers, and Schultz and co-workers, were used to reconstruct the Vredefort impact event, using a final crater diameter of 300 km, as estimated by Therriault. The sequence of events (stages 2-5) is illustrated diagramatically. The stages are: initial penetration, excavation and compression, dynamic rebound and uplift, maximum radial growth and collapse, and final crater form.

  13. Impact of atmospheric and physical forcings on biogeochemical cycling of dissolved oxygen and nutrients in the coastal Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S; Sridevi, B.; Maneesha, K.; Sridevi, T.; Naidu, S; Prasad, V.R; Venkataramana, V.; Acharya, T.; Bharati, M; Subbaiah, C.V; Kiran, B.S.; Reddy, N.P.C.; Sarma, V.V.; Sadhuram, Y.; Murty, T.V.R.

    structure displayed inversions of 0.5 to 1.0 degrees C during winter and were weaker in summer. The water column was vertically stratified during the entire study period and was stronger during October-November 2007 and August-December 2008 compared to other...

  14. Resilience of hydraulic structures under significant impact of typhoons

    Directory of Open Access Journals (Sweden)

    Zhi-min FU

    2011-09-01

    Full Text Available Vulnerability to natural disasters falls into three categories: exposure, resistance, and resilience, where resilience mainly refers to the capability of a pressure-bearing system to recover by returning to its initial state, that is, the ability to adapt to disaster pressure. Resilience is a major subject of research on disaster prevention and mitigation. This research mainly focuses on the ability of the hydraulic structure to recover from the significant impacts of typhoons. According to the load/unload response ratio theory, the degree of instability by which nonlinear systems can be identified according to the difference between load and unload responses was analyzed. This analysis was used as a basis to study the resilience of a hydraulic structure. Taking the Yangtze River embankments under the impact of Typhoon Matsa as an example, the ability of the typical sections of different types of embankments to adapt to the significant impact of the typhoon, i.e., the resilience of the hydraulic structure, is described with the help of the load/unload response ratio (L. The results of the calculated resilience reflect the actual conditions of the structure and can be used to determine the applicability of the embankment section. The load/unload response ratio theory is one of the effective tools for calculating the resilience of hydraulic structures under the significant impacts of typhoons.

  15. Macrozooplankton predation impact on anchovy (Engraulis encrasicolus) eggs mortality at the Bay of Biscay shelf break spawning centre

    KAUST Repository

    Albaina, Aitor

    2014-11-23

    A real-time PCR based method involving a species-specific probe was applied to detect Engraulis encrasicolus eggs predation by the macrozooplankton community during the 2011 spawning season. Three locations along the shelf break presenting contrasting but high prey densities were sampled. A total of 840 individuals from 38 taxa of potential macrozooplankton predators were assayed for E. encrasicolus DNA presence and 27 presented at least one positive signal. Carnivorous copepods were responsible for the most predation events (66%) followed by euphausiids (16%), chaetognaths (5%), and myctophid fish (4%). Macrozooplankton predation on anchovy eggs followed a type-I functional response with daily mortalities <4% of available prey abundance suggesting a negligible impact on the species recruitment at the shelf break spawning centre. © 2014 International Council for the Exploration of the Sea 2014. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Bayes linear statistics, theory & methods

    CERN Document Server

    Goldstein, Michael

    2007-01-01

    Bayesian methods combine information available from data with any prior information available from expert knowledge. The Bayes linear approach follows this path, offering a quantitative structure for expressing beliefs, and systematic methods for adjusting these beliefs, given observational data. The methodology differs from the full Bayesian methodology in that it establishes simpler approaches to belief specification and analysis based around expectation judgements. Bayes Linear Statistics presents an authoritative account of this approach, explaining the foundations, theory, methodology, and practicalities of this important field. The text provides a thorough coverage of Bayes linear analysis, from the development of the basic language to the collection of algebraic results needed for efficient implementation, with detailed practical examples. The book covers:The importance of partial prior specifications for complex problems where it is difficult to supply a meaningful full prior probability specification...

  17. Discovery of Discrete Structured Bubbles within Lunar Regolith Impact Glasses

    OpenAIRE

    Marek S. Żbik; Yen-Fang Song; Chun-Chieh Wang; Ray L. Frost

    2012-01-01

    The unusual morphology and internal structure of bubbles within lunar regolith impact glasses have been studied using traditional scanning electron microscopy and the novel technique transmission X-ray microscopy (TXM), with 3D tomography reconstruction. Here, we show the previously unknown phenomenon of building a highly porous cellular structure within bubbles in glassy particles of the dust fraction of lunar regolith. Vesicles within studied lunar glasses are filled in with submicron-sized...

  18. High Velocity Impact Response of Composite Lattice Core Sandwich Structures

    Science.gov (United States)

    Wang, Bing; Zhang, Guoqi; Wang, Shixun; Ma, Li; Wu, Linzhi

    2014-04-01

    In this research, carbon fiber reinforced polymer (CFRP) composite sandwich structures with pyramidal lattice core subjected to high velocity impact ranging from 180 to 2,000 m/s have been investigated by experimental and numerical methods. Experiments using a two-stage light gas gun are conducted to investigate the impact process and to validate the finite element (FE) model. The energy absorption efficiency (EAE) in carbon fiber composite sandwich panels is compared with that of 304 stainless-steel and aluminum alloy lattice core sandwich structures. In a specific impact energy range, energy absorption efficiency in carbon fiber composite sandwich panels is higher than that of 304 stainless-steel sandwich panels and aluminum alloy sandwich panels owing to the big density of metal materials. Therefore, in addition to the multi-functional applications, carbon fiber composite sandwich panels have a potential advantage to substitute the metal sandwich panels as high velocity impact resistance structures under a specific impact energy range.

  19. The impact of terrigeneous inputs on the Bay of Ouinné (New Caledonia) phytoplankton communities: A spectrofluorometric and microscopic approach

    Science.gov (United States)

    Tenório, M. M. B.; Le Borgne, R.; Rodier, M.; Neveux, J.

    2005-08-01

    The impact of terrigeneous inputs on the phytoplankton composition was studied during a 2.5 months daily survey in the Bay of Ouinné, a deep cove on the south-eastern coast of New Caledonia. Surface waters benefited from nutrients originating from nearby land drainage and the Ouinné river outflow during periods of heavy rain. The nutrient composition mirrored the composition of the drained soils, with concentrations reaching 3-4 μM for nitrate and 0.13 μM for phosphate at the river mouth. In addition to nutrient inputs, significant quantities of particulate matter (inorganic and organic compounds) were discharged into the lagoon during heavy rain periods, resulting in transitory decreases of the photic layer depth and enrichments of the water column through remineralization processes. Changes in contributions of the main phytoplankton groups in response to terrigeneous inputs were shown by chlorophyll and phycobiliprotein spectrofluorometric analyses. While dry periods were marked by the dominance of pico- ( Prochlorococcus, and high-phycourobilin (PUB) Synechococcus) and microcyanobacteria ( Trichodesmium spp.), developments of various eukaryote populations resulted from land drainage occurring during the wet periods. This was indicated by the increase of accessory chlorophyll pigments that doubled at a depth of 15 m: chlorophyll b (chlorophytes), chlorophyll c1+ c2 (associated with diatoms and dinoflagellates), chlorophyll c3 (associated with c1 and/or c2 in prymnesiophytes, chrysophytes and/or pelagophytes). In addition, Synechococcus with a high phycoerythrobilin (PEB) content also appeared to be stimulated by river outputs. Finally, microscopic observations of the >35 μm net plankton confirmed the greater presence of diatoms and dinoflagellates during periods of rain compared to Trichodesmium, particularly in the surface layer.

  20. Hypervelocity Impact Evaluation of Metal Foam Core Sandwich Structures

    Science.gov (United States)

    Yasensky, John; Christiansen, Eric L.

    2007-01-01

    A series of hypervelocity impact (HVI) tests were conducted by the NASA Johnson Space Center (JSC) Hypervelocity Impact Technology Facility (HITF) [1], building 267 (Houston, Texas) between January 2003 and December 2005 to test the HVI performance of metal foams, as compared to the metal honeycomb panels currently in service. The HITF testing was conducted at the NASA JSC White Sands Testing Facility (WSTF) at Las Cruces, New Mexico. Eric L. Christiansen, Ph.D., and NASA Lead for Micro-Meteoroid Orbital Debris (MMOD) Protection requested these hypervelocity impact tests as part of shielding research conducted for the JSC Center Director Discretionary Fund (CDDF) project. The structure tested is a metal foam sandwich structure; a metal foam core between two metal facesheets. Aluminum and Titanium metals were tested for foam sandwich and honeycomb sandwich structures. Aluminum honeycomb core material is currently used in Orbiter Vehicle (OV) radiator panels and in other places in space structures. It has many desirable characteristics and performs well by many measures, especially when normalized by density. Aluminum honeycomb does not perform well in Hypervelocity Impact (HVI) Testing. This is a concern, as honeycomb panels are often exposed to space environments, and take on the role of Micrometeoroid / Orbital Debris (MMOD) shielding. Therefore, information on possible replacement core materials which perform adequately in all necessary functions of the material would be useful. In this report, HVI data is gathered for these two core materials in certain configurations and compared to gain understanding of the metal foam HVI performance.

  1. Calculation of forces arising from impacting projectiles upon yielding structures

    International Nuclear Information System (INIS)

    Calculations concerning the impact of airplanes upon nuclear power plant buildings usually imply that the building [QUOTE]acts' as a rigid target. This assumption is justified for considerations concerning the structural integrity of the building being hit. However, for investigating induced vibrations of components within the structure, this approach might-in general-be too conservative. It is expected, that yielding of the structure during impact reduces the peak values of the loads and changes the temporal behaviour of the load function which is obtained for a rigid target. To calculate the changes of the load function which are due to deformations of the structure, Riera's method is extended for the case of a yielding target. The calculations are performed with a one-dimensional model for the projectile. The presented model calculations seem to verify that the motion of the target does not have much influence on the impact force for projectiles similar to the model projectile, provided the displacement of the yielding target is small in comparison with the path covered by the free-flying projectile during a time which is equivalent to the total time of impact. (Auth.)

  2. Calculation of forces arising from impacting projectiles upon yielding structures

    International Nuclear Information System (INIS)

    Calculations concerning the impact of airplanes upon nuclear power plant buildings usually imply that the building 'acts' as a rigid target. This assumption is justified for considerations concerning the structural integrity of the building being hit. However, for investigating induced vibrations of components within the structure, this approach might -in general- be too conservative. It is expected, that yielding of the structure during impact reduces the peak values of the loads and changes the temporal behavior of the load function which is obtained for a rigid target. To calculate the changes of the load function which are due to deformations of the structure, Riera's method is extended for the case of a yielding target. In view of the applications of the calculations to the impact of airplanes upon buildings which are constructed to withstand loads of this kind without serious damage and without large deformations, it is possible to simplify the calculations to some extent. That is, the investigations need not take into account in detail the behavior of the target during impact. The calculations are performed with a one-dimensional model for the projectile. The direction of impact is perpendicular to the target surface; direction of impact and projectile axis coincide. The calculations were performed for several initial velocities of the projectiles simulating a fast flying military airplane. Variations of the peak values of the load functions as compared to corresponding values for a rigid target do not exceed about 10%. The overall temporal behavior of the load curves turns out to be not very sensitive to the yielding of the target, though, in some cases displacements in time of the peak positions within a single load curve do arise

  3. Meteorite impact craters and possibly impact-related structures in Estonia

    Science.gov (United States)

    Plado, Jüri

    2012-10-01

    Three structures (Neugrund, Kärdla, and Kaali) of proven impact origin make Estonia the most cratered country in the world by area. In addition, several candidate impact structures exist, waiting for future studies to determine their origin. This article is an overview of these proven and possible impact structures, including some breccia layers. It summarizes the information and descriptions of the morphology; geological characteristics; and mineralogical, chemical, and geophysical data available in the literature. The overview was prepared to make information in many earlier publications in local journals (many of which had been published in Estonian or Russian) accessible to the international community. This review summarizes the facts and observations in a historical fashion, summarizing the current state of knowledge with some additional comments, and providing the references.

  4. San Diego Bay Bibliography

    OpenAIRE

    Brueggeman, Peter

    1994-01-01

    The San Diego Bay Bibliography references the scientific & gray literature on the Bay up through 1994 and it is NOT current. Compiled from numerous resources (including Hubbs-Sea World Research Institute, Regional Water Quality Control Board, & local library catalogs), it is not comprehensive since so the Bay literature is elusive. In addition, there can be duplicate references varying in completeness. The San Diego Bay Bibliography is the outcome of discussion and networking within ...

  5. A Glance at Bohai Bay Oil Province

    Institute of Scientific and Technical Information of China (English)

    Gao Shoubai

    1995-01-01

    @@ Chinese oil industry keeps on developing in 1994. The oil production of Bohai Bay Oil Province located in East China also keeps on growing. Geologically,the total area of Bohai Bay Basin is about 200 000 km2 and the main structural units are: Liaohe Depression, Huanghua Depression,Jizhong Depression, Linqing Depression, Jiyang Depression, Changwei Depression, Bozhong Depression,Chengning Uplift and Cangjing Uplift (see figure 1). Area of the main structural units is listed in following:

  6. Reproduction and structure of the population of the Chaetognath Parasagitta friderici in Guanabara Bay (Brazil based on short term sampling

    Directory of Open Access Journals (Sweden)

    Fabiana Mendes

    2012-03-01

    Full Text Available The aim of this study was to describe the total density, densities of developmental stages and the reproduction period of Parasagitta friderici. Weekly samples were collected at one station in the channel of Guanabara Bay, Rio de Janeiro, during one year. Three vertical hauls were made for each sample, and P. friderici was separated, the developmental stages were identified, and body length (BL, ovary length (OL and seminal vesicle width (SVW were measured. Throughout the year P. friderici was the most abundant chaetognath species occurring in all four developmental stages, the densities of which varied from week to week. Higher densities of adults occurred in the spring, followed by peaks of juveniles in the summer. Although P. friderici seems to reproduce continuously in Guanabara Bay, a reproductive peak was apparent during the spring. The intensification of reproduction during the spring, with juveniles occurring in the summer, seems to be related to the period of higher food supply during the rainy season and intrusions of the South Atlantic Central Water.O objetivo deste estudo foi descrever a densidade total, densidades dos estágios de desenvolvimento e o período reprodutivo de Parasagitta friderici. As coletas foram realizadas semanalmente durante um ano em uma estação no canal da Baía de Guanabara, Rio de Janeiro. Foram realizados três arrastos verticais em cada amostragem e, P. friderici foi separada, os estágios de desenvolvimento identificados e o comprimento do corpo, comprimento dos ovários e a largura da vesícula seminal foram medidos. Ao longo do ano, P. friderici foi a espécie de Chaetognatha mais abundante, ocorrendo em todos os quatro estágios de desenvolvimento, dos quais as densidades variaram entre as semanas. As densidades mais altas de adultos ocorreram na primavera seguidas de picos de juvenis no verão. Embora, P. friderici se reproduza continuamente na baía de Guanabara, um pico reprodutivo foi aparente

  7. Guard Ring Width Impact on Impact Parameter Performances and Structure Simulations

    CERN Document Server

    Gouldwell, A; Rahman, M; Bates, R; Wemyss, M; Murphy, G; Turner, P; Biagi, S F

    2003-01-01

    The 1 mm guard ring structure of the VELO sensors has been simulated. The performance of the baseline design is considered and a design which improves the electric field characteristics proposed. Designs which would permit a reduced guard ring width, to 0.5 mm or better, are also discussed and shown to also have similarly good electric field performances. The effect of implementing these designs on the impact parameter resolution of LHCb is found to be better than 5 %. This design is currently being fabricated. Finally, a very different structure, the trench guard ring, is considered which would then allow an impact parameter resolution improvement of approximately 7 %.

  8. Structure and Dynamics of Coauthorship, Citation, and Impact within CSCW

    CERN Document Server

    Keegan, Brian; Finholt, Thomas A; Kaye, Joseph "Jofish"

    2013-01-01

    CSCW has stabilized as an interdisciplinary venue for computer, information, cognitive, and social scientists but has also undergone significant changes in its format in recent years. This paper uses methods from social network analysis and bibliometrics to re-examine the structures of CSCW a decade after its last systematic analysis. Using data from the ACM Digital Library, we analyze changes in structures of coauthorship and citation between 1986 and 2013. Statistical models reveal significant but distinct patterns between papers and authors in how brokerage and closure in these networks affects impact as measured by citations and downloads. Specifically, impact is unduly influenced by structural position, such that ideas introduced by those in the core of the CSCW community (e.g., elite researchers) are advantaged over those introduced by peripheral participants (e.g., newcomers). This finding is examined in the context of recent changes to the CSCW conference that may have the effect of upsetting the pref...

  9. Numerical and Experimental Studies on Impact Loaded Concrete Structures

    International Nuclear Information System (INIS)

    An experimental set-up has been constructed for medium scale impact tests. The main objective of this effort is to provide data for the calibration and verification of numerical models of a loading scenario where an aircraft impacts against a nuclear power plant. One goal is to develop and take in use numerical methods for predicting response of reinforced concrete structures to impacts of deformable projectiles that may contain combustible liquid ('fuel'). Loading, structural behaviour, like collapsing mechanism and the damage grade, will be predicted by simple analytical methods and using non-linear FE-method. In the so-called Riera method the behavior of the missile material is assumed to be rigid plastic or rigid visco-plastic. Using elastic plastic and elastic visco-plastic material models calculations are carried out by ABAQUS/Explicit finite element code, assuming axisymmetric deformation mode for the missile. With both methods, typically, the impact force time history, the velocity of the missile rear end and the missile shortening during the impact were recorded for comparisons. (authors)

  10. Impact of Financial Structure on the Cost of Solar Energy

    Energy Technology Data Exchange (ETDEWEB)

    Mendelsohn, M.; Kreycik, C.; Bird, L.; Schwabe, P.; Cory, K.

    2012-03-01

    To stimulate investment in renewable energy generation projects, the federal government developed a series of support structures that reduce taxes for eligible investors--the investment tax credit, the production tax credit, and accelerated depreciation. The nature of these tax incentives often requires an outside investor and a complex financial arrangement to allocate risk and reward among the parties. These financial arrangements are generally categorized as 'advanced financial structures.' Among renewable energy technologies, advanced financial structures were first widely deployed by the wind industry and are now being explored by the solar industry to support significant scale-up in project development. This report describes four of the most prevalent financial structures used by the renewable sector and evaluates the impact of financial structure on energy costs for utility-scale solar projects that use photovoltaic and concentrating solar power technologies.

  11. A full Bayes before-after study accounting for temporal and spatial effects: Evaluating the safety impact of new signal installations.

    Science.gov (United States)

    Sacchi, Emanuele; Sayed, Tarek; El-Basyouny, Karim

    2016-09-01

    Recently, important advances in road safety statistics have been brought about by methods able to address issues other than the choice of the best error structure for modeling crash data. In particular, accounting for spatial and temporal interdependence, i.e., the notion that the collision occurrence of a site or unit times depend on those of others, has become an important issue that needs further research. Overall, autoregressive models can be used for this purpose as they can specify that the output variable depends on its own previous values and on a stochastic term. Spatial effects have been investigated and applied mostly in the context of developing safety performance functions (SPFs) to relate crash occurrence to highway characteristics. Hence, there is a need for studies that attempt to estimate the effectiveness of safety countermeasures by including the spatial interdependence of road sites within the context of an observational before-after (BA) study. Moreover, the combination of temporal dynamics and spatial effects on crash frequency has not been explored in depth for SPF development. Therefore, the main goal of this research was to carry out a BA study accounting for spatial effects and temporal dynamics in evaluating the effectiveness of a road safety treatment. The countermeasure analyzed was the installation of traffic signals at unsignalized urban/suburban intersections in British Columbia (Canada). The full Bayes approach was selected as the statistical framework to develop the models. The results demonstrated that zone variation was a major component of total crash variability and that spatial effects were alleviated by clustering intersections together. Finally, the methodology used also allowed estimation of the treatment's effectiveness in the form of crash modification factors and functions with time trends. PMID:27249403

  12. The design of impact absorbing structures for additive manufacture

    International Nuclear Information System (INIS)

    Additive manufacturing (AM) is increasingly becoming a viable manufacturing process due to dramatic advantages that it facilitates in the area of design complexity. This paper investigates the potential of additively manufactured lattice structures for the application of tailored impact absorption specifically for conformal body protection. It explores lattice cell types based on foam microstructures and assesses their suitability for impact absorption. The effect of varying the cell strut edge design is also investigated. The implications of scaling these cells up for AM are discussed as well as the design issues regarding the handling of geometric complexity and the requirement for body conformity. The suitability of AM materials for this application is also discussed.

  13. The Impact of Tourism on the Sociocultural Structure of Cyprus

    OpenAIRE

    2006-01-01

    This paper is based on evaluating tourism development in Cyprus, a European nation, and its impacts on the socio-cultural structure of the island. The principal concern of this research is aid in sustaining the resource base on which the tourism development in Cyprus depends on. The paper concludes that in spite of all the negative and positive impacts of tourism on Cyprus it is not yet clear whether the benefits outweigh the costs. The reason for this uncertainty is that most of the research...

  14. Impact of the Ownership Structure on Corporate Management in Engineering

    Directory of Open Access Journals (Sweden)

    Dieieva Nataliia E.

    2014-02-01

    Full Text Available The article analyses impact of the ownership structure on corporate management in the engineering industry of Ukraine. In order to detect impact of the structure of corporate ownership on corporate management the article uses general scientific and special methods of study: method of critical analysis and generalisation of theoretical studies, comparison method and statistical method. Analysis of engineering enterprises confirmed availability of impact of the structure of corporate ownership on corporate management. The article also shows that the engineering industry of Ukraine is characterised with the concentrated ownership structure, which has the following features: restriction of rights of minority shareholders with respect to management and control in a joint stock company; availability of corporate conflicts between majority and minority shareholders; availability of intense control of owners over management, which influences efficiency of making managerial decisions; hired managers and enterprise employees have no possibility to acquire stock of a joint stock company including in the form of bonuses and incentives; the controlling owner is interested in efficient activity of the enterprise and tries to create necessary conditions for this. The conducted studies give a possibility to establish that a share of stock that belongs to a hired executive body is smaller in those joint stock companies in which concentration of ownership is higher. The article also shows that the higher ownership concentration the higher is the probability that the owner would be a part of controlling bodies.

  15. Impact induced solitary wave propagation through a woodpile structure

    Science.gov (United States)

    Kore, R.; Waychal, A.; Agarwal, S.; Yadav, P.; Uddin, Ahsan; Sahoo, N.; Shelke, A.

    2016-02-01

    In this paper, we investigate solitary wave propagation through a one-dimensional woodpile structure excited by low and high velocity impact. Woodpile structures are a sub-class of granular metamaterial, which supports propagation of nonlinear waves. Hertz contact law governs the behavior of the solitary wave propagation through the granular media. Towards an experimental study, a woodpile structure was fabricated by orthogonally stacking cylindrical rods. A shock tube facility has been developed to launch an impactor on the woodpile structure at a velocity of 30 m s-1. Embedded granular chain sensors were fabricated to study the behavior of the solitary wave. The impact induced stress wave is studied to investigate solitary wave parameters, i.e. contact force, contact time, and solitary wave velocity. With the aid of the experimental setup, numerical simulations, and a theoretical solution based on the long wavelength approximation, formation of the solitary wave in the woodpile structure is validated to a reasonable degree of accuracy. The nondispersive and compact supported solitary waves traveling at sonic wave velocity offer unique properties that could be leveraged for application in nondestructive testing and structural health monitoring.

  16. Seasonal variability in free-living marine nematode community structure in a sandy beach of the Taiping Bay of Qingdao, China

    Institute of Scientific and Technical Information of China (English)

    LIU Haibin; ZHANG Zhinan; FAN Shiliang; HUA Er; DENG Ke

    2008-01-01

    Nematode assemblage composition,trophic structure and biodiversity were followed over an annual cycle in a sandy beach of the Taiping Bay of Qingdao,China.Nematode assemblage in the sandy beach maintained a high genus diversity (75 genera).Micro-laimus and Bathylaimus were the dominant genus of the nematode assemblage,accounting for 66% of the total nematode abun-dance.The nematodes' dominant trophic structure changed seasonally as a response to the seasonal changes in food quality.Epi-growth-feeder nematodes (2A) were the dominant trophic groups in the trophic structure with the highest abundance in spring be-cause of phytoplankton bloom,while the feeding type (1B) showed higher abundance in summer that was due to the increasing of sediment detritus after spring bloom.Furthermore,species diversity and evenness calculated on nematodes identified to the genus level displayed significant temporal changes,which was also reflected by the index of trophic diversity.According to the cluster analysis,the nematode community structure of the whole year was clearly separated into two periods ( A and B).Biota-Environ-ment matching (BIOENV) results showed that seawater temperature,sediment Chl a and grain size were responsible for the nema-tode community structure variation in spring and summer period (Period A).However,seawater/interstitial water temperature,interstitial water dissolved oxygen concentration,interstitial water salinity,and sediment Ph a a were more important in construc-ting the autumn and winter period ( Period B) nematode community structure.

  17. Bayes Multiple Decision Functions

    CERN Document Server

    Wu, Wensong

    2011-01-01

    This paper deals with the problem of simultaneously making many (M) binary decisions based on one realization of a random data matrix X. M is typically large and X will usually have M rows associated with each of the M decisions to make, but for each row the data may be low dimensional. A Bayesian decision-theoretic approach for this problem is implemented with the overall loss function being a cost-weighted linear combination of Type I and Type II loss functions. The class of loss functions considered allows for the use of the false discovery rate (FDR), false nondiscovery rate (FNR), and missed discovery rate (MDR) in assessing the decision. Through this Bayesian paradigm, the Bayes multiple decision function (BMDF) is derived and an efficient algorithm to obtain the optimal Bayes action is described. In contrast to many works in the literature where the rows of the matrix X are assumed to be stochastically independent, we allow in this paper a dependent data structure with the associations obtained through...

  18. Computerized simulation of missile impacts on reinforced concrete structures

    International Nuclear Information System (INIS)

    The results are discussed of a theoretical study of the impact stress of reinforced concrete structures, with emphasis on the computerized modeling of missile impacts. Attention is paid to the following four problems in the numerical modeling: space discretization, computation instabilities, deformation rate, and projectile-target interaction. The program FINEDAN, enabling the dynamics of the continuum to be solved in the two-dimensional Cartesian as well as cylindrical geometry by using the finite elements method, was tested in an experiment where a steel bar was impacted on a circular reinforced concrete target. The results are shown in graphical form. Similar experiments performed in the FRG and the UK are briefly characterized; these experiments were also employed in testing the FINEDAN program. (Z.M.). 11 figs., 1 tab., 9 refs

  19. Structural evaluation on the impact of a radioisotope package

    International Nuclear Information System (INIS)

    A package to transport high-level radioactive materials is required to withstand normal transport and hypothetical accident conditions pursuant to the IAEA and domestic regulations. The package should maintain the structural safety not to release radioactive material in any condition. The structural safety of the package has been evaluated by test using proto-type or scaled-down models, however, the method by analysis is gradually utilized due to recent advancement of computers and computer codes. In this paper, to evaluate the structural safety of a radioisotope package of the KAERI, the three dimensional impact analyses under 9 m free drop and 1 m puncture were performed with an explicit finite-element code, the LS-DYNA3D code. The maximum stress intensity on each part was calculated and the structural safety of the package was evaluated in accordance with the regulations. (author)

  20. Transient Dynamic Response and Failure of Sandwich Composite Structures under Impact Loading with Fluid Structure Interaction

    Science.gov (United States)

    Kwon, Y. W.; Violette, M. A.; McCrillis, R. D.; Didoszak, J. M.

    2012-12-01

    The objective of this study is to examine the Fluid Structure Interaction (FSI) effect on transient dynamic response and failure of sandwich composite structures under impact loading. The primary sandwich composite used in this study consisted of a 6.35 mm balsa core and a multi-ply symmetrical plain weave 6 oz E-glass skin. Both clamped sandwich composite plates and beams were studied using a uniquely designed vertical drop-weight testing machine. There were three impact conditions on which these experiments focused. The first of these conditions was completely dry (or air surrounded) testing. The second condition was completely water submerged. The final condition was also a water submerged test with air support at the backside of the plates. The tests were conducted sequentially, progressing from a low to high drop height to determine the onset and spread of damage to the sandwich composite when impacted with the test machine. The study showed the FSI effect on sandwich composite structures is very critical such that impact force, strain response, and damage size are generally much greater with FSI under the same impact condition. As a result, damage initiates at much lower impact energy conditions with the effect of FSI. Neglecting to account for FSI effects on sandwich composite structures results in very non-conservative analysis and design. Additionally, it was observed that the damage location changed for sandwich composite beams with the effect of FSI.

  1. Impact origin of the Sudbury structure: Evolution of a theory

    Science.gov (United States)

    Lowman, Paul D., Jr.

    1992-01-01

    This paper reviews the origin, development, and present status of the widely accepted theory, proposed by Robert S. Dietz in 1962, that the Sudbury structure was formed by meteoritic or asteroidal impact. The impact theory for the origin of the Sudbury structure seems supported by a nearly conclusive body of evidence. However, even assuming an impact origin to be correct, at least three major questions require further study: (1) the original size and shape of the crater, before tectonic deformation and erosion; (2) the source of the melt now forming the Sudbury Igneous Complex; and (3) the degree, if any, to which the Ni-Cu-platinum group elements are meteoritic. The history of the impact theory illustrates several under-appreciated aspects of scientific research: (1) the importance of cross-fertilization between space research and terrestrial geology; (2) the role of the outsider in stimulating thinking by insiders; (3) the value of small science, at least in the initial stages of an investigation, Dietz's first field work having been at his own expense; and (4) the value of analogies (here, between the Sudbury Igneous Complex and the maria), which although incorrect in major aspects, may trigger research on totally new lines. Finally, the Sudbury story illustrates the totally unpredictable and, by implication, unplannable nature of basic research, in that insight to the origin of the world's then-greatest Ni deposit came from the study of tektites and the Moon.

  2. Impact of active controls technology on structural integrity

    Science.gov (United States)

    Noll, Thomas; Austin, Edward; Donley, Shawn; Graham, George; Harris, Terry

    1991-01-01

    This paper summarizes the findings of The Technical Cooperation Program to assess the impact of active controls technology on the structural integrity of aeronautical vehicles and to evaluate the present state-of-the-art for predicting the loads caused by a flight-control system modification and the resulting change in the fatigue life of the flight vehicle. The potential for active controls to adversely affect structural integrity is described, and load predictions obtained using two state-of-the-art analytical methods are given.

  3. Performance improvement of car body structure in 100 % frontal impact

    Institute of Scientific and Technical Information of China (English)

    Men Yongxin; Peng Hong; Du Lina; Chen Wei; Wang Zelong

    2012-01-01

    During the 100 % front impact, all the parts of front car will participate in the course;the crash stiffness of bodywork will also reach the peak. During the crash, rational structure of bodywork can resist the distortion, absorb more energy and get better mode of distortion and low deceleration rate, so as to meet the performance of crash safety. The paper mainly makes optimization analysis based on the problems of front side rails, subframe, firewall, and optimization cases are confirmed which can decrease the intrusion and deceleration rate of the whole car. The structure of bodywork ,after optimization can meet the performance of crash safety.

  4. The impact of structural genomics: the first quindecennial.

    Science.gov (United States)

    Grabowski, Marek; Niedzialkowska, Ewa; Zimmerman, Matthew D; Minor, Wladek

    2016-03-01

    The period 2000-2015 brought the advent of high-throughput approaches to protein structure determination. With the overall funding on the order of $2 billion (in 2010 dollars), the structural genomics (SG) consortia established worldwide have developed pipelines for target selection, protein production, sample preparation, crystallization, and structure determination by X-ray crystallography and NMR. These efforts resulted in the determination of over 13,500 protein structures, mostly from unique protein families, and increased the structural coverage of the expanding protein universe. SG programs contributed over 4400 publications to the scientific literature. The NIH-funded Protein Structure Initiatives alone have produced over 2000 scientific publications, which to date have attracted more than 93,000 citations. Software and database developments that were necessary to handle high-throughput structure determination workflows have led to structures of better quality and improved integrity of the associated data. Organized and accessible data have a positive impact on the reproducibility of scientific experiments. Most of the experimental data generated by the SG centers are freely available to the community and has been utilized by scientists in various fields of research. SG projects have created, improved, streamlined, and validated many protocols for protein production and crystallization, data collection, and functional analysis, significantly benefiting biological and biomedical research. PMID:26935210

  5. Impact of commodity index rolls on the futures term structure

    OpenAIRE

    Roslander, Risto-Matti

    2013-01-01

    OBJECTIVES OF THE STUDY: In this thesis, I study the effects of commodity index rolls on nearby commodity futures returns and futures term structure. More specifically, I examine the impact of commodity index investors' and speculators' positions on roll yields of nearby futures contracts during the "Goldman roll". In addition, I study the futures returns in the post-rolling period. Furthermore, by employing daily dollar volumes, my objective is to calculate the effect of liquidity in the...

  6. Demography of an apex predator at the edge of its range: impacts of changing sea ice on polar bears in Hudson Bay

    Science.gov (United States)

    Lunn, Nicholas J.; Servanty, Sabrina; Regehr, Eric V.; Converse, Sarah J.; Richardson, Evan S.; Stirling, Ian

    2016-01-01

    Changes in the abundance and distribution of wildlife populations are common consequences of historic and contemporary climate change. Some Arctic marine mammals, such as the polar bear (Ursus maritimus), may be particularly vulnerable to such changes due to the loss of Arctic sea ice. We evaluated the impacts of environmental variation on demographic rates for the Western Hudson Bay (WH), polar bear subpopulation from 1984 to 2011 using live-recapture and dead-recovery data in a Bayesian implementation of multistate capture–recapture models. We found that survival of female polar bears was related to the annual timing of sea ice break-up and formation. Using estimated vital rates (e.g., survival and reproduction) in matrix projection models, we calculated the growth rate of the WH subpopulation and projected population responses under different environmental scenarios while accounting for parametric uncertainty, temporal variation, and demographic stochasticity. Our analysis suggested a long-term decline in the number of bears from 1185 (95% Bayesian credible interval [BCI] = 993–1411) in 1987 to 806 (95% BCI = 653–984) in 2011. In the last 10 yr of the study, the number of bears appeared stable due to temporary stability in sea ice conditions (mean population growth rate for the period 2001–2010 = 1.02, 95% BCI = 0.98–1.06). Looking forward, we estimated long-term growth rates for the WH subpopulation of ~1.02 (95% BCI = 1.00–1.05) and 0.97 (95% BCI = 0.92–1.01) under hypothetical high and low sea ice conditions, respectively. Our findings support previous evidence for a demographic linkage between sea ice conditions and polar bear population dynamics. Furthermore, we present a robust framework for sensitivity analysis with respect to continued climate change (e.g., to inform scenario planning) and for evaluating the combined effects of climate change and management actions on the status of wildlife populations.

  7. Impacts of Watershed Characteristics and Crop Rotations on Winter Cover Crop Nitrate-Nitrogen Uptake Capacity within Agricultural Watersheds in the Chesapeake Bay Region.

    Directory of Open Access Journals (Sweden)

    Sangchul Lee

    Full Text Available The adoption rate of winter cover crops (WCCs as an effective conservation management practice to help reduce agricultural nutrient loads in the Chesapeake Bay (CB is increasing. However, the WCC potential for water quality improvement has not been fully realized at the watershed scale. This study was conducted to evaluate the long-term impact of WCCs on hydrology and NO3-N loads in two adjacent watersheds and to identify key management factors that affect the effectiveness of WCCs using the Soil and Water Assessment Tool (SWAT and statistical methods. Simulation results indicated that WCCs are effective for reducing NO3-N loads and their performance varied based on planting date, species, soil characteristics, and crop rotations. Early-planted WCCs outperformed late-planted WCCs on the reduction of NO3-N loads and early-planted rye (RE reduced NO3-N loads by ~49.3% compared to the baseline (no WCC. The WCCs were more effective in a watershed dominated by well-drained soils with increased reductions in NO3-N fluxes of ~2.5 kg N·ha-1 delivered to streams and ~10.1 kg N·ha-1 leached into groundwater compared to poorly-drained soils. Well-drained agricultural lands had higher transport of NO3-N in the soil profile and groundwater due to increased N leaching. Poorly-drained agricultural lands had lower NO3-N due to extensive drainage ditches and anaerobic soil conditions promoting denitrification. The performance of WCCs varied by crop rotations (i.e., continuous corn and corn-soybean, with increased N uptake following soybean crops due to the increased soil mineral N availability by mineralization of soybean residue compared to corn residue. The WCCs can reduce N leaching where baseline NO3-N loads are high in well-drained soils and/or when residual and mineralized N availability is high due to the cropping practices. The findings suggested that WCC implementation plans should be established in watersheds according to local edaphic and agronomic

  8. Impact of Hurricane Irene on Vibrio vulnificus and Vibrio parahaemolyticus concentrations in surface water, sediment and cultured oysters in the Chesapeake Bay, Maryland, USA

    Directory of Open Access Journals (Sweden)

    KristiSShaw

    2014-05-01

    Full Text Available To determine if a storm event (i.e., high winds, large volumes of precipitation could alter concentrations of Vibrio vulnificus and Vibrio parahaemolyticus in aquacultured oysters (Crassostrea virginica and associated surface water and sediment, this study followed a sampling timeline before and after Hurricane Irene impacted the Chesapeake Bay estuary in late August 2011. Aquacultured oysters were sampled from two levels in the water column: surface 0.3 m and near-bottom just above the sediment. Concentrations of each Vibrio spp. and associated virulence genes were measured in oysters with a combination of real-time PCR and most probable number enrichment methods, and in sediment and surface water with real-time PCR. While concentration shifts of each Vibrio species were apparent post-storm, statistical tests indicated no significant change in concentration change for either Vibrio species by location (surface or near bottom oysters or date sampled (oyster tissue, surface water and sediment concentrations. V. vulnificus in oyster tissue was correlated with total suspended solids (r=0.41, p=0.04, and V. vulnificus in sediment was correlated with secchi depth (r=-0.93, p< 0.01, salinity (r=-0.46, p=0.02, tidal height (r=-0.45, p=0.03, and surface water V. vulnificus (r=0.98, p< 0.01. V. parahaemolyticus in oyster tissue did not correlate with environmental measurements, but V. parahaemolyticus in sediment and surface water correlated with several measurements including secchi depth (r=-0.48, p=0.02[sediment]; r=-0.97 p< 0.01[surface water] and tidal height (r=-0.96. p< 0.01[sediment], r=-0.59,p< 0.01 [surface water]. The concentrations of Vibrio spp. were higher in oysters relative to other studies (average V. vulnificus 4x105 MPN g-1, V. parahaemolyticus 1x105 MPN g-1, and virulence-associated genes were detected in most oyster samples. This study provides a first estimate of storm-related Vibrio density changes in oyster tissues, sediment and

  9. Electronic structure of novel air-stable n-type organic semiconductors: A comparison of different bay-substituted perylene-bisimide dyes

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, Markus; Fiedler, Sebastian; Schoell, Achim [Universitaet Wuerzburg, Experimentelle Physik VII, Wuerzburg (Germany); Schmidt, Ruediger; Wuerthner, Frank [Universituet Wuerzburg, Institut fuer Organische Chemie (Germany); Reinert, Friedrich [Universitaet Wuerzburg, Experimentelle Physik VII, Wuerzburg (Germany); Gemeinschaftslabor fuer Nanoanalytik, Karlsruher Institut fuer Technologie, Karlsruhe (Germany)

    2011-07-01

    The development of air stable n-conducting organic semiconductors are one of the current bottle necks in organic electronic. We present a comparative analysis of the electronic structure of various bay-substituted perylene bisimide (PBI) dyes, which have already demonstrated very high mobilities in thin film devices. The occupied and unoccupied valence levels were investigated by UPS and IPES, which allows determining the transport gap. Interestingly, the transport gap does not differ substantially between the different compounds. If the contact properties to a Ag(111) metal substrate are investigated, work function measurements reveal strong interface dipoles. In case of PBIs with fluoro alkyl chains the interface dipole is about 0.7 eV, which can be related to the C{sub 4}F{sub 7}-chains oriented out of the film surface. For Films of PBIs with isopropylphenyl-groups the magnitude and the direction of the interface dipole depend strongly on the film preparation and provide a possible route for a tailoring of the interfacial electronic structure.

  10. Impact testing and analysis for structural code benchmarking

    International Nuclear Information System (INIS)

    Sandia National Laboratories, in cooperation with industry and other national laboratories, has been benchmarking computer codes used to predict the structural, thermal, criticality, and shielding behavior of radioactive materials packages. The first step in the benchmarking of the codes was to develop standard problem sets and to compare the results from several codes and users. This step for structural analysis codes has been completed as described in Structural Code Benchmarking for the Analysis of Impact Response of Nuclear Material Shipping Casks, R.E. Glass, Sandia National Laboratories, 1985. The problem set is shown in Fig. 1. This problem set exercised the ability of the codes to predict the response to end (axisymmetric) and side (plane strain) impacts with both elastic and elastic/plastic materials. The results from these problems showed that there is good agreement in predicting elastic response. Significant differences occurred in predicting strains for the elastic/plastic models. An example of the variation in predicting plastic behavior is given, which shows the hoop strain as a function of time at the impacting end of Model B. These differences in predicting plastic strains demonstrated a need for benchmark data for a cask-like problem

  11. Rare earth impact on glass structure and alteration kinetics

    International Nuclear Information System (INIS)

    This work is related to the question of the geological deep repository of high-level waste glass. These wastes include fission products and minor actinides, elements which can be simulated by rare earths. As new glass compositions could enable increased rare earth concentrations, it is crucial to know and understand rare earth impact on glass structure on the one hand, and on glass alteration kinetics or their incorporation into an altered layer. This work studied simplified borosilicate glasses in order to limit synergetic effects between rare earths and other elements. Various complementary techniques were used to characterize pristine and altered glasses (solid-high resolution NMR, Raman spectroscopy, fluorescence, SIMS, SAXS). Firstly, the structural role of a rare earth is discussed and is compared to a calcium cation. The local environment of rare earths is also probed. Secondly, rare earth (nature and concentration) impact on several alteration regimes was studied (initial rate, rate drop). Then, after alteration, rare earth elements being retained within the altered layer, the structural impact of rare earth elements (and their local environment) in this alteration layer was also investigated. (author)

  12. Residues of Polychlorinated Biphenyls (PCBs) in Sediment from CauBay River and Their Impacts on Agricultural Soil, Human Health Risk in KieuKy Area, Vietnam.

    Science.gov (United States)

    Toan, Vu Duc; Quy, Nguyen Phuong

    2015-08-01

    An evaluation of the PCB residues from CauBay River and KieuKy area, Vietnam was carried out. CauBay River has been playing an important role in irrigated water supply for agriculture activities at KieuKy area in the downstream. The PCBs concentrations of sediment, soil samples were analyzed and obtained results indicated the wide extent of contamination of PCBs in CauBay River (from 30.74 to 167.35 ng g(-1) dry weight) and KieuKy area (from 21.62 to 60.22 ng g(-1) dry weight). This clearly reflected the effect of PCB residues from CauBay River to the quality of agricultural soil of the KieuKy area. The PCBs composition analyses in the samples reflect their long-time release. The total cancer risk of PCBs in the soil of KieuKy fell into the very low range suggesting low risk. However, since PCBs were the species of POPs with more concern in this area, ecological risk assessment should be further investigated. PMID:26088763

  13. The Net Impact of Hydroelectric Reservoir Creation on Greenhouse Gas Emissions: A Study of the Eastmain-1 Reservoir in the Eastern James Bay region of Quebec, Canada

    Science.gov (United States)

    Strachan, I. B.; Lemieux, M.; Bonneville, M.; Roulet, N.; Tremblay, A.

    2009-05-01

    In order to satisfy present and future energy demands and to minimize greenhouse gas (GHG) emissions, there is a growing need to develop energy sources that are not based on combustion. In the boreal regions of Canada, there is a huge potential for hydroelectricity production. However, in most cases, large areas of the boreal ecosystem must be inundated to create hydroelectric reservoirs. Previous studies have established that reservoirs emit GHGs, but these studies have typically focused on emissions some years after reservoir creation. The critical question that has not been asked is 'what is the net change in the exchange of GHG that results directly from the creation of the reservoir?' - i.e. 'what is the net difference between the landscape scale exchange of GHGs before and after reservoir creation, and how does that net difference change over time from when the reservoir was first created to when it reaches a steady-state condition?'. The Eastmain-1 (EM-1) hydroelectric reservoir, located in the James Bay region of Quebec was created in late 2005 and provides a tremendous opportunity to study the impacts of reservoir creation on GHG emissions which are still largely unknown for this type of land conversion. The creation of the EM-1 hydroelectric reservoir required the flooding of over 600 km2 of the boreal ecosystem along the Eastmain River, of which 65% was occupied by forest, 14% by peatland, and 21% by lakes and rivers. In order to assess the impacts of the creation of the reservoir on GHG emissions, three eddy covariance (EC) tower flux sites were established in a black spruce forest, peatland and on an island in the reservoir itself to measure continuous net ecosystem exchange (NEE) of CO2. Together, these represent the dominant terrestrial pre-flooded (forest and peatland) and post-flooded (reservoir) environments. The forest and reservoir EC systems were installed and operational by the end of summer 2006 with the peatland site coming on-line summer of

  14. CRASH SAFETY OF A TYPICAL BAY TABLE IN A RAILWAY VEHICLE

    Directory of Open Access Journals (Sweden)

    Emmanuel MATSIKA

    2015-12-01

    Full Text Available Increasingly, urban and high speed trains are incorporating tables (workstations as common railway vehicle interior furniture because passengers prefer seating by bay tables. Among table design characteristics, the most challenging is meeting crashworthiness requirements. Past accident data and sled test results have shown that in the event of railway vehicle frontal impact, occupants located in the bay seating are exposed to chest and abdominal injuries upon contact with tables resulting from secondary collision. In some cases tables have tended to be structurally weak; they easily detach from the side walls and/or floor mounting. Subsequently these become unguided missiles that strike occupants, resulting in injuries. This paper presents an analysis of the crash performance of a typical bay table. The results provide some understanding of the table’s crash safety, giving an indication of its impact aggression. Table materials are characterised using quasi-static compressive tests. In addition, experimental dynamic (impact tests are conducted using a pendulum representing a body block (mass. The results provide information about the possible loading of the table on the occupant in the event of a crash. Contact forces are compared with chest and abdominal injury tolerance thresholds to infer the collision injury potential. Recommendations are then made on design of bay tables to meet the “functional-strength-and-safety balance”.

  15. Power and dignity: the social consequences of hydro-electric development for the James Bay Cree

    International Nuclear Information System (INIS)

    The social impact that large-scale hydro-electric development has on the Cree of James Bay following the construction of the La Grande Complex was discussed. Many environmental changes were brought about by dam construction. The project, which also involved the first settlement (the James Bay and Northern Quebec Agreement) directed at extinguishing aboriginal title to land and natural resources in Canada, resulted in several relocations of Cree communities. In addition to compensation, the Agreement included a formal procedure for environmental and social impact assessment for development projects. However, there was little commitment, as a matter of corporate or government policy, to monitoring any of the social impacts. This paper is a preliminary response to an appeal for attention to be focused on the social consequences of hydro-electric development for the Cree in James Bay. Data from social service files indicate that the rapid centralization of the James Bay Cree into structured communities led to social instability in the villages, reflected by high frequencies in suicide, neglect of children, vandalism and drug and alcohol abuse. The material presented here is expected to serve as a warning that in further developing the far North of Quebec the pace of social change in Cree society will have to be slowed down to avoid social destruction of the native communities. 15 refs., 2 tabs

  16. Use of Stable Carbon and Nitrogen Isotopes for Trophic Levels Evaluation and Food Webs Reconstruction: The Bay of Biscay Case Study

    International Nuclear Information System (INIS)

    The Bay of Biscay is a very large bay opened on the North-East Atlantic Ocean. The continental shelf covers over 220 000 km2. The hydrological structure is influenced by 2 main rivers plumes (Loire and Gironde) and a continental slope indented by numerous canyons. The Bay of Biscay supports both numerous important fisheries and a rich fauna including many protected species (e.g., marine mammals). The management of this ecosystem subjected to numerous anthropogenic impacts notably depends on the good understanding of its food webs' structure. Within each major group of taxa, spatial groups displayed significantly different δ13C and δ15N values (KW tests, all p 13C and δ15N values decreased from near-shore organisms to deep-sea or oceanic organisms. These results highlighted the existence of several food webs with distinct baseline signatures in the Bay of Biscay. Differences in δ15N values in particular are linked to processes occurring at the Dissolved Inorganic Nitrogen (DIN) level, and to nutrients and particulate organic matter available for primary production in general. Therefore, the contrasted hydrological landscapes from the Bay of Biscay probably impact signatures of the primary producers in the different areas of the Bay.

  17. Impacts of Size Structure on Intraguild Predation in Pond Communities

    Science.gov (United States)

    Crumrine, P. W.

    2005-05-01

    Size structure, the degree to which individuals in a population vary in size, can greatly influence the dynamics of intraguild predation (IGP) within ecological communities. I manipulated the degree of size structure within assemblages of IG predators and IG prey to examine impacts on the direction and intensity of IGP in communities of larval dragonflies and larval water beetles. In pond enclosure studies, Pachydiplax longipennis (IG prey) mortality was lower when exposed to size structured assemblages of Anax junius (IG predator) than when exposed to only large A. junius at the same density. Effects of size-structured assemblages of A. junius on shared prey, Ischnura verticalis, were similar to the effects each size class alone at the same density. Separate experiments with Dytiscid water beetle larvae as IG predators and size-structured assemblages of A. junius as IG prey suggest that IG prey size structure plays only a limited role in mediating shared prey survival. These experiments highlight the importance of size structure as a characteristic that may promote the coexistence of predators in IGP systems.

  18. Computational modeling and impact analysis of textile composite structures

    Science.gov (United States)

    Hur, Hae-Kyu

    This study is devoted to the development of an integrated numerical modeling enabling one to investigate the static and the dynamic behaviors and failures of 2-D textile composite as well as 3-D orthogonal woven composite structures weakened by cracks and subjected to static-, impact- and ballistic-type loads. As more complicated modeling about textile composite structures is introduced, some of homogenization schemes, geometrical modeling and crack propagations become more difficult problems to solve. To overcome these problems, this study presents effective mesh-generation schemes, homogenization modeling based on a repeating unit cell and sinusoidal functions, and also a cohesive element to study micro-crack shapes. This proposed research has two: (1) studying behavior of textile composites under static loads, (2) studying dynamic responses of these textile composite structures subjected to the transient/ballistic loading. In the first part, efficient homogenization schemes are suggested to show the influence of textile architectures on mechanical characteristics considering the micro modeling of repeating unit cell. Furthermore, the structures of multi-layered or multi-phase composites combined with different laminar such as a sub-laminate, are considered to find the mechanical characteristics. A simple progressive failure mechanism for the textile composites is also presented. In the second part, this study focuses on three main phenomena to solve the dynamic problems: micro-crack shapes, textile architectures and textile effective moduli. To obtain a good solutions of the dynamic problems, this research attempts to use four approaches: (I) determination of governing equations via a three-level hierarchy: micro-mechanical unit cell analysis, layer-wise analysis accounting for transverse strains and stresses, and structural analysis based on anisotropic plate layers, (II) development of an efficient computational approach enabling one to perform transient

  19. Geochemical Comparison of Four Cores from the Manson Impact Structure

    Science.gov (United States)

    Korotev, Randy L.; Rockow, Kaylynn M.; Jolliff, Bradley L.; Haskin, Larry A.; McCarville, Peter; Crossey, Laura J.

    1996-01-01

    Concentrations of 33 elements were determined in relatively unaltered, matrix-rich samples of impact breccia at approximately 3-m-depth intervals in the M-1 core from the Manson impact structure, Iowa. In addition, 46 matrix-rich samples from visibly altered regions of the M-7, M-8, and M-10 cores were studied, along with 42 small clasts from all four cores. Major element compositions were determined for a subset of impact breccias from the M-1 core, including matrix-rich impact-melt breccia. Major- and trace-element compositions were also determined for a suite of likely target rocks. In the M-1 core, different breccia units identified from lithologic examination of cores are compositionally distinct. There is a sharp compositional discontinuity at the boundary between the Keweenawan-shale-clast breccia and the underlying unit of impact-melt breccia (IMB) for most elements, suggesting minimal physical mixing between the two units during emplacement. Samples from the 40-m-thick IMB (M-1) are all similar to each other in composition, although there are slight increases in concentration with depth for those elements that have high concentrations in the underlying fragmental-matrix suevite breccia (SB) (e.g., Na, Ca, Fe, Sc), presumably as a result of greater clast proportions at the bottom margin of the unit of impact-melt breccia. The high degree of compositional similarity we observe in the impact-melt breccias supports the interpretation that the matrix of this unit represents impact melt. That our analyses show such compositional similarity results in part from our technique for sampling these breccias: for each sample we analyzed a few small fragments (total mass: approximately 200 mg) selected to be relatively free of large clasts and visible signs of alteration instead of subsamples of powders prepared from a large mass of breccia. The mean composition of the matrix-rich part of impact-melt breccia from the M-1 core can be modeled as a mixture of approximately

  20. Nature of anisotropy of impact toughness of structural steels with ferrite-pearlite structure

    Science.gov (United States)

    Goritskii, V. M.; Shneyderov, G. R.; Lushkin, M. A.

    2013-10-01

    The anisotropy of the impact toughness of low-alloy steels of various compositions and purities with a ferrite-pearlite structure has been investigated using samples of type 11 according to the Russian Standard GOST 9454-78. It has been established that the anisotropy coefficient of the impact toughness depends on the anisotropy coefficient of the work of crack propagation and is independent of the degree of striation of the ferrite-pearlite structure and the work for nucleation of the ductile crack.

  1. Nelson River and Hudson Bay

    Science.gov (United States)

    2002-01-01

    Rivers that empty into large bodies of water can have a significant impact on the thawing of nearshore winter ice. This true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from May 18, 2001, shows the Nelson River emptying spring runoff from the Manitoba province to the south into the southwestern corner of Canada's Hudson Bay. The warmer waters from more southern latitudes hasten melting of ice near the shore, though some still remained, perhaps because in shallow coastal waters, the ice could have been anchored to the bottom. High volumes of sediment in the runoff turned the inflow brown, and the rim of the retreating ice has taken on a dirty appearance even far to the east of the river's entrance into the Bay. The sediment would have further hastened the melting of the ice because its darker color would have absorbed more solar radiation than cleaner, whiter ice. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  2. Optimum structure of Whipple shield against hypervelocity impact

    International Nuclear Information System (INIS)

    Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

  3. Fully nonlinear simulation for fluid/structure impact: A review

    Science.gov (United States)

    Sun, Shili; Wu, Guoxiong

    2014-09-01

    This paper presents a review of the work on fluid/structure impact based on inviscid and imcompressible liquid and irrotational flow. The focus is on the velocity potential theory together with boundary element method (BEM). Fully nonlinear boundary conditions are imposed on the unknown free surface and the wetted surface of the moving body. The review includes (1) vertical and oblique water entry of a body at constant or a prescribed varying speed, as well as free fall motion, (2) liquid droplets or column impact as well as wave impact on a body, (3) similarity solution of an expanding body. It covers two dimensional (2D), axisymmetric and three dimensional (3D) cases. Key techniques used in the numerical simulation are outlined, including mesh generation on the multivalued free surface, the stretched coordinate system for expanding domain, the auxiliary function method for decoupling the mutual dependence of the pressure and the body motion, and treatment for the jet or the thin liquid film developed during impact.

  4. Impact-generated endolithic habitat within crystalline rocks of the Haughton impact structure, Devon Island, Canada.

    Science.gov (United States)

    Pontefract, Alexandra; Osinski, Gordon R; Cockell, Charles S; Moore, Casey A; Moores, John E; Southam, Gordon

    2014-06-01

    The colonization of rocks by endolithic communities is an advantageous trait, especially in environments such as hot or cold deserts, where large temperature ranges, low water availability, and high-intensity ultraviolet radiation pose a significant challenge to survival and growth. On Mars, similar conditions (albeit more extreme) prevail. In these environments, meteorite impact structures could provide refuge for endolithic organisms. Though initially detrimental to biology, an impact event into a rocky body can favorably change the availability and habitability of a substrate for endolithic organisms, which are then able to (re)colonize microfractures and pore spaces created during the impact. Here, we show how shocked gneisses from the Haughton impact structure, Devon Island, Canada, offer significant refuge for endolithic communities. A total of 28 gneiss samples representing a range of shock states were analyzed, collected from in situ, stable field locations. For each sample, the top centimeter of rock was examined with confocal scanning laser microscopy, scanning electron microscopy, and bright-field microscopy to investigate the relationship of biomass with shock level, which was found to correlate generally with increased shock state and particularly with increased porosity. We found that gneisses, which experienced pressures between 35 and 60 GPa, provide the most ideal habitat for endolithic organisms. PMID:24926727

  5. Fracture of reinforced concrete structural members and structures subjected to impact or explosion

    International Nuclear Information System (INIS)

    The deformation and fracture modes of reinforced concrete structural members and structures subjected to impact or impulsive loadings are of great multiplicity by mainly the application speed of these loadings. It is considered that the multiplicity, mentioned above, is attributed by the rate effects on the constitutive equations and failure criteria of concrete, reinforcement and bond action and existing stress waves, because the magnitude of the rate effects and the stress waves have different tendencies respectively with the increment of speed of loadings. This paper deals with the study on the estimation of the sorts and magnitude of the responses of the reinforced concrete structural members and structures subjected to various types of impact or explosion. (orig.)

  6. Late-summer zooplankton community structure, abundance, and distribution in the Hudson Bay system (Canada) and their relationships with environmental conditions, 2003-2006

    Science.gov (United States)

    Estrada, Rafael; Harvey, Michel; Gosselin, Michel; Starr, Michel; Galbraith, Peter S.; Straneo, Fiammetta

    2012-08-01

    Zooplankton communities were examined for the first time in three different hydrographic regions of the Hudson Bay system (HBS) in early August to early September from 2003 to 2006. Sampling was conducted at 50 stations distributed along different transects located in Hudson Bay (HB), Hudson Strait (HS), and Foxe Basin (FB). Variations in zooplankton biomass, abundance, taxonomic composition, and diversity in relation to environmental variables were studied using multivariate techniques. During all sampling years, the total zooplankton biomass was on average four times lower in HB than in HS and FB. Clustering samples by their relative species compositions revealed no interannual variation in zooplankton community but showed a marked interregional variability between the three regions. Water column stratification explained the greatest proportion (25%) of this spatial variability. According to redundancy analysis (RDA), the zooplankton taxa that contribute most to the separation of the three regions are Microcalanus spp., Oithona similis, Oncaea borealis, Aeginopsis laurentii, Sagitta elegans, Fritillaria sp., and larvae of cnidaria, chaetognatha, and pteropoda in HB; hyperiid amphipods in FB; and Pseudocalanus spp. CI-CV, Calanus glacialis CI-CVI, Calanus finmarchicus CI-CVI, Calanus hyperboreus CV-CVI, Acartia longiremis CI-CV, Metridia longa N3-N6 CI-CIII CVIf, Eukrohnia hamata, larvae of echinodermata, mollusca, cirripedia, appendicularia, and polychaeta in the northwestern and southeastern HS transects. For the HB transect, the RDA analyzed allowed us to distinguish three regions (HB west, central, and east) with different environmental gradients and zooplankton assemblages, in particular higher concentration of Pseudocalanus spp. nauplii and CI-CVI, as well as benthic macrozooplankton and meroplankton larvae in western HB. In HS, Calanoid species (mainly C. finmarchicus and C. glacialis) were mostly observed at the north shore stations associated with the

  7. Dynamic links between shape of the eddy viscosity profile and the vertical structure of tidal current amplitude in bays and estuaries

    Science.gov (United States)

    Chen, Wei; de Swart, Huib E.

    2016-03-01

    Several field studies in bays and estuaries have revealed pronounced subsurface maxima in the vertical profiles of the current amplitude of the principal tidal harmonic, or of its vertical shear, over the water column. To gain fundamental understanding about these phenomena, a semi-analytical model is designed and analysed, with focus on the sensitivity of the vertical structure of the tidal current amplitude to formulations of the vertical shape of the eddy viscosity. The new analytical solutions for the tidal current amplitude are used to explore their dependence on the degree of surface mixing, the vertical shape of eddy viscosity in the upper part of the water column and the density stratification. Sources of surface mixing are wind and whitecapping. Results show three types of current amplitude profiles of tidal harmonics, characterised by monotonically decreasing shear towards the surface, "surface jumps" (vertical shear of tidal current amplitude has a subsurface maximum) and "subsurface jets" (maximum tidal current amplitude below the surface), respectively. The "surface jumps" and "subsurface jets" both occur for low turbulence near the surface, whilst additionally the surface jumps only occur if the eddy viscosity in the upper part of the water column decreases faster than linearly to the surface. Furthermore, "surface jumps" take place for low density stratification, while and "subsurface jets" occur for high density stratification. The physics causing the presence of surface jumps and subsurface jets is also discussed.

  8. An assessment of the trophic structure of the Bay of Biscay continental shelf food web: Comparing estimates derived from an ecosystem model and isotopic data

    Science.gov (United States)

    Lassalle, G.; Chouvelon, T.; Bustamante, P.; Niquil, N.

    2014-01-01

    Comparing outputs of ecosystem models with estimates derived from experimental and observational approaches is important in creating valuable feedback for model construction, analyses and validation. Stable isotopes and mass-balanced trophic models are well-known and widely used as approximations to describe the structure of food webs, but their consistency has not been properly established as attempts to compare these methods remain scarce. Model construction is a data-consuming step, meaning independent sets for validation are rare. Trophic linkages in the French continental shelf of the Bay of Biscay food webs were recently investigated using both methodologies. Trophic levels for mono-specific compartments representing small pelagic fish and marine mammals and multi-species functional groups corresponding to demersal fish and cephalopods, derived from modelling, were compared with trophic levels calculated from independent carbon and nitrogen isotope ratios. Estimates of the trophic niche width of those species, or groups of species, were compared between these two approaches as well. A significant and close-to-one positive (rSpearman2 = 0.72 , n = 16, p trophic levels estimated by Ecopath modelling and those derived from isotopic signatures. Differences between estimates were particularly low for mono-specific compartments. No clear relationship existed between indices of trophic niche width derived from both methods. Given the wide recognition of trophic levels as a useful concept in ecosystem-based fisheries management, propositions were made to further combine these two approaches.

  9. Stability of reef framework and post settlement mortality as the structuring factor for recovery of Malakal Bay Reef, Palau, Micronesia: 25 years after a severe COTS outbreak

    Science.gov (United States)

    Victor, Steven

    2008-03-01

    Corals in Malakal Bay reefs were devastated in the 1979 Crown of Thorns Starfish (COTS) outbreak. It has been almost 30 years since the outbreak and coral cover at the study sites have not come close to the cover before the outbreak. A question is asked: what factors may contribute to the slow recovery of these reefs: recruitment or post-settlement mortality? Two habitat types within the reef systems were monitored using coral transplants to determine if corals can survive in these environments and recruitment tiles to see if there are larvae coming into the system. The study revealed that coral survivorship is high in the fore reef areas compared to the reef channel slopes and that larvae is not a limiting factor to natural recovery. Stability of the reef framework, i.e. unstable rubble substrate, and possibly high post settlement mortality, are the structuring factors that determine the recovery process in these reef systems and possibly so for similar habitats in other reef systems throughout Palau.

  10. An age-structured population model for horseshoe crabs in the Delaware Bay area to assess harvest and egg availability for shorebirds

    Science.gov (United States)

    Sweka, J.A.; Smith, D.R.; Millard, M.J.

    2007-01-01

    The objective of this simulation study was to create an age-structured population model for horseshoe crabs (Limulus polyphenols) in the Delaware Bay region using best available estimates of age-specific mortality and recent harvest levels. Density dependence was incorporated using a spatial model relating egg mortality with abundance of spawning females. Combinations of annual female harvest (0, 50, 100, and 200 thousand), timing of female harvest (before or after spawning), and three levels of density-dependent egg mortality were simulated. The probability of the population increasing was high (> 80%) with low and medium egg mortality and harvest less than 200 thousand females per year. Under the high egg mortality case, the probability of the population increasing was population growth. The number of eggs available to shorebirds was highest when egg mortality was lowest and female abundance was at its highest levels. Although harvest and egg mortality influenced population growth and food availability to shorebirds, sensitivity and elasticity analyses showed that early-life stage mortality, age 0 mortality in particular, was the most important parameter for population growth. Our modeling results indicate areas where further research is needed and suggest effective management will involve a combination of harvest management and actions to increase early juvenile survival. ?? 2007 Estuarine Research Federation.

  11. Phytoplankton size structure in the southern Bay of Bengal modified by the Summer Monsoon Current and associated eddies: Implications on the vertical biogenic flux..

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Vinayachandran, P. N.; Madhu, N.V.; Robin, R.S.; Karman, C.; Jagadeesan, L.; Anjusha, A.

    is missed out in satellite imageries (Prasannakumar et al., 2007; Jyothibabu et al., 2008a, Vinayachandran, 2009). Although the general understanding suggests contrasting effects of cyclonic and anti-cyclonic eddies on phytoplankton production in the Bay... et al., 1996; Prasannakumar et al., 2007; Vinayachandran, 2009). During the Southwest Monsoon, the hydrography of the northern Bay of Bengal is heavily influenced by the rainfall and river influx and as a result the surface salinity drops...

  12. Connectivity patterns of anchovy larvae in the Bay of Biscay from a coupled transport-bioenergetic model forced by size-structured zooplankton

    OpenAIRE

    Huret, Martin; Vandromme, Pieter; Petitgas, Pierre; Pecquerie, Laure

    2012-01-01

    Connectivity during early life stages of pelagic fish, defined here by survival probability between spawning and early juvenile habitats, depends on a combination of sufficient food availability and low predator encounter along drift trajectories. For anchovy in the Bay of Biscay, larval transport experiments throughout the spawning season suggest accumulation of early juveniles in the offshore area of the southern Bay, as well as retention over the mid-shelf at mid-latitude. However, late su...

  13. Tampa Bay: Chapter N

    Science.gov (United States)

    Handley, Larry; Spear, Kathryn; Cross, Lindsay; Baumstark, René; Moyer, Ryan; Thatcher, Cindy

    2013-01-01

    Tampa Bay is Florida’s largest open-water estuary and encompasses an area of approximately 1036 km2 (400 mi2) (Burgan and Engle, 2006; TBNEP, 2006). The Bay’s watershed drains 5,698 km2 (2,200 mi2) of land and includes freshwater from the Hillsborough River to the north east, the Alafia and Little Manatee rivers to the east, and the Manatee River to the south (Figure 1). Freshwater inflow also enters the bay from the Lake Tarpon Canal, from small tidal tributaries, and from watershed runoff. Outflow travels from the upper bay segments (Hillsborough Bay and Old Tampa Bay) into Middle and Lower Tampa Bay. Southwestern portions of the water shed flow through Boca Ciega Bay into the Intracoastal Waterway and through the Southwest Channel and Passage Key Inlet into the Gulf of Mexico. The average depth in most of Tampa Bay is only 3.4 m (11 ft); however, 129 km (80 mi) of shipping channels with a maximum depth of 13.1 m (43 ft) have been dredged over time and are regularly maintained. These channels help to support the three ports within the bay, as well as commercial and recreational boat traffic.

  14. Detection of erosion events using 10Be profiles: example of the impact of agriculture on soil erosion in the Chesapeake Bay area (U.S.A.)

    Science.gov (United States)

    Valette-Silver, J. N.; Brown, L.; Pavich, M.; Klein, J.; Middleton, R.

    1986-01-01

    10Be concentration, total carbon and grain-size were measured in cores collected in undisturbed estuarine sediments of three tributaries of the Chesapeake Bay. These cores were previously studied by Davis [1] and Brush [2,3] for pollen content, age and sedimentation rate. In this work, we compare the results obtained for these various analyses. In the cores, we observed two increases in 10Be concentration concomitant with two major changes in the pollen composition of the sediments. These two pollen changes each correspond to well-dated agricultural horizons reflecting different stages in the introduction of European farming techniques [2]. In the Chesapeake Bay area, the agricultural development, associated with forest clearing, appears to have triggered the erosion, transport, and sedimentation into the river mouths of large quantities of 10Be-rich soils. This phenomenon explains the observed rise in the sedimentation rate associated with increases in agricultural land-use. ?? 1986.

  15. Impacts of Hypersaline Conditions on the Biotransformation and Toxicity of the Pesticide Bifenthrin in Salmonid Species of the San Francisco Bay Delta

    OpenAIRE

    Riar, Navneet

    2012-01-01

    Pyrethroids are synthetic derivatives of pyrethrin insecticides whose urban usage and continuous municipal wastewater discharge results in "pseudo-persistent" levels in Northern California waterways. Climate change causes warmer global temperatures which diminishes snowfall and reduces freshwater input into the San Francisco Bay Delta (SFBD) resulting in increased salinity over time. The SFBD and its drainage serve as spawning and rearing habitat for salmonid species and is under threat by m...

  16. Grid faults' impact on wind turbine structural loads

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.D.; Cutululis, N.A.; Soerensen, P.; Larsen, T.J. [Risoe National Lab., DTU, Wind Energy Dept. (Denmark); Iov, F.

    2007-11-15

    The objective of this work is to illustrate the impact of the grid faults on the wind turbine structural loads. Grid faults are typically in detailed power system simulation tools, which by applying simplified mechanical models, are not able to provide a throughout insight on the structural loads caused by sudden disturbances on the grid. On the other hand, structural loads of the wind turbine are typically assessed in advanced aeroelastic computer codes, which by applying simplified electrical models do not provide detailed electrical insight. This paper presents a simulation strategy, where the focus is on how to access a proper combination of two complementary simulation tools, such as the advanced aeroelastic computer code HAWC2 and the detailed power system simulation tool DIgSILENT, in order to provide a whole overview of both the structural and the electrical behaviour of the wind turbine during grid faults. The effect of a grid fault on the wind turbine flexible structure is assessed for a typical fixed speed wind turbine, equipped with an induction generator. (au)

  17. Sound structure and input frequency impact on noun plural acquisition

    DEFF Research Database (Denmark)

    Kjærbæk, Laila; Christensen, René dePont; Basbøll, Hans

    2014-01-01

    This study analyses the emergence of the noun plural category in typically developing Danish-speaking children from its first appearance up to the age of 10 years, focusing on the impact of sound structure and input frequency. We use a multi-method research approach comparing different data types...... (dictionary data, naturalistic spontaneous child language input and output, semi-naturalistic/semi-experimental data, experimental data and reported data). We define cross-linguistically three degrees of stem changes (NO CHANGE, PROSODIC CHANGE, PHONEMIC CHANGE), and we also define three degrees...

  18. A Structured Approach for Evaluating Risk Impacts in IT Projects

    OpenAIRE

    Saeed, Muhammad; Ziauddin, Mehmood

    2008-01-01

    Date: 12-June-2008 Authors: Muhammad Saeed – 760721 Västerås – Sweden Mehmood Ziauddin – 830730 Västerås – Sweden Title: A Structured Approach for Evaluating Risk Impacts in IT Projects Introduction: Risk is an integral part of any project and it’s more appropriate to say for IT because it is changing with a very fast pace. Different surveys, reports and researches show astonishing statistics about the risks in IT projects. Through proper risk assessment techniques most of the uncertainties c...

  19. Optimized body structure and packaging for car ODB impact performance

    Institute of Scientific and Technical Information of China (English)

    Men Yongxin; Ma Fangwu; Wang Zhitao; Wang Zelong; Peng Hong

    2012-01-01

    Front bumper, crash box and side rail are key body structural parts in front crash. Deformation space is affected by compartment packaging. The improvement suggestions are proposed to solve the problems existed in the current vehicle struc- ture and compartment packaging based on the areas that influence performance of automobile offset deformable barrier impact, such as the side rail, mounting, storage battery packaging,etc. It is proved that dO % offset crash simulation result of one certain car is well-correlated with the physical test. Optimization cases meet the crash performance requirements. The objec- tive of the analysis is to guide structural design and improves a car' s crash safety performance.

  20. Impact of upwelling events on the sea water carbonate chemistry and dissolved oxygen concentration in the Gulf of Papagayo (Culebra Bay, Costa Rica: Implications for coral reefs

    Directory of Open Access Journals (Sweden)

    Tim Rixen

    2012-04-01

    Full Text Available The Gulf of Papagayo, Pacific coast of Costa Rica, is one of the three seasonal upwelling areas of Mesoamerica. In April 2009, a 29-hour experiment was carried out at the pier of the Marina Papagayo, Culebra Bay. We determined sea surface temperature (SST, dissolved oxygen concentration, salinity, pH, and the partial pressure of CO2 (pCO2. The aragonite saturation state (Ωa as well as the other parameters of the marine carbonate system such as the total dissolved inorganic carbon (DIC and the total alkalinity (TA were calculated based on the measured pH and the pCO2. The entrainment of subsurface waters raised the pCO2 up to 645 µatm. SSTs, dissolved oxygen concentrations decreased form 26.4 to 23.7°C and from 228 to 144 µmol l-1. Ωa dropped down to values of 2.1. Although these changes are assumed to reduce the coral growth, the main reef building coral species within the region (Pocillopora spp. and Pavona clavus reveal growth rates exceeding those measured at other sites in the eastern tropical Pacific. This implies that the negative impact of upwelling on coral growth might be overcompensated by an enhanced energy supply caused by the high density of food and nutrients and more favorable condition for coral growth during the non-upwelling season.El Golfo de Papagayo, costa Pacífica de Costa Rica, es una de las tres regiones de afloramiento estacional de Mesoamérica. Las características físicas y químicas del agua que aflora no habían sido estudiadas. Durante 29 horas en Abril 2009, se estudiaron la temperatura superficial del mar (TSM, la concentración de oxígeno disuelto, salinidad, pH y la presión parcial de CO2 (pCO2, en la Marina Papagayo, Bahía Culebra. Con base en las mediciones de pH y pCO2 se calculó el estado de saturación de la aragonita (Ω y otros parámetros del sistema de carbonatos como lo es el carbono orgánico disuelto (COD y la alcalinidad total (AT. Los resultados indican que el arrastre por convecci

  1. Community composition, structure, and interrelationships in the marine intertidal Endocladia muricata – Balanus glandula association in Monterey Bay, California

    NARCIS (Netherlands)

    Glynn, Peter W.

    1965-01-01

    Studies of the community composition, structure and species interrelationships of the Endocladia-Balanus association were carried out on the rocky shores at the Hopkins Marine Station, Pacific Grove, California, over the period 1959—1961. The organisms making up this biotic association form a horizo

  2. Impact of methionine oxidation on calmodulin structural dynamics

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, Megan R.; Thompson, Andrew R.; Nitu, Florentin [Biochemistry, Molecular Biology and Biophysics Department, University of Minnesota, Minneapolis, MN 55455 (United States); Moen, Rebecca J. [Chemistry and Geology Department, Minnesota State University, Mankato, MN 56001 (United States); Olenek, Michael J. [Biology Department, University of Wisconsin, La Crosse, WI 54601 (United States); Klein, Jennifer C., E-mail: jklein@uwlax.edu [Biology Department, University of Wisconsin, La Crosse, WI 54601 (United States); Thomas, David D., E-mail: ddt@umn.edu [Biochemistry, Molecular Biology and Biophysics Department, University of Minnesota, Minneapolis, MN 55455 (United States)

    2015-01-09

    Highlights: • We measured the distance distribution between two spin labels on calmodulin by DEER. • Two structural states, open and closed, were resolved at both low and high Ca. • Ca shifted the equilibrium toward the open state by a factor of 13. • Methionine oxidation, simulated by glutamine substitution, decreased the Ca effect. • These results have important implications for aging in muscle and other tissues. - Abstract: We have used electron paramagnetic resonance (EPR) to examine the structural impact of oxidizing specific methionine (M) side chains in calmodulin (CaM). It has been shown that oxidation of either M109 or M124 in CaM diminishes CaM regulation of the muscle calcium release channel, the ryanodine receptor (RyR), and that mutation of M to Q (glutamine) in either case produces functional effects identical to those of oxidation. Here we have used site-directed spin labeling and double electron–electron resonance (DEER), a pulsed EPR technique that measures distances between spin labels, to characterize the structural changes resulting from these mutations. Spin labels were attached to a pair of introduced cysteine residues, one in the C-lobe (T117C) and one in the N-lobe (T34C) of CaM, and DEER was used to determine the distribution of interspin distances. Ca binding induced a large increase in the mean distance, in concert with previous X-ray crystallography and NMR data, showing a closed structure in the absence of Ca and an open structure in the presence of Ca. DEER revealed additional information about CaM’s structural heterogeneity in solution: in both the presence and absence of Ca, CaM populates both structural states, one with probes separated by ∼4 nm (closed) and another at ∼6 nm (open). Ca shifts the structural equilibrium constant toward the open state by a factor of 13. DEER reveals the distribution of interprobe distances, showing that each of these states is itself partially disordered, with the width of each

  3. Oligothiophene wires: impact of torsional conformation on the electronic structure.

    Science.gov (United States)

    Kislitsyn, D A; Taber, B N; Gervasi, C F; Zhang, L; Mannsfeld, S C B; Prell, J S; Briseno, A L; Nazin, G V

    2016-02-14

    Charge transport in polymer- and oligomer-based semiconductor materials depends strongly on the structural ordering of the constituent molecules. Variations in molecular conformations influence the electronic structures of polymers and oligomers, and thus impact their charge-transport properties. In this study, we used Scanning Tunneling Microscopy and Spectroscopy (STM/STS) to investigate the electronic structures of different alkyl-substituted oligothiophenes displaying varied torsional conformations on the Au(111) surface. STM imaging showed that on Au(111), oligothiophenes self-assemble into chain-like structures, binding to each other via interdigitated alkyl ligands. The molecules adopted distinct planar conformations with alkyl ligands forming cis- or trans- mutual orientations. For each molecule, by using STS mapping, we identify a progression of particle-in-a-box-like states corresponding to the LUMO, LUMO+1 and LUMO+2 orbitals. Analysis of STS data revealed very similar unoccupied molecular orbital energies for different possible molecular conformations. By using density functional theory calculations, we show that the lack of variation in molecular orbital energies among the different oligothiophene conformers implies that the effect of the Au-oligothiophene interaction on molecular orbital energies is nearly identical for all studied torsional conformations. Our results suggest that cis-trans torsional disorder may not be a significant source of electronic disorder and charge carrier trapping in organic semiconductor devices based on oligothiophenes. PMID:26804474

  4. eBay.com

    DEFF Research Database (Denmark)

    Engholm, Ida

    2014-01-01

    Celebrated as one of the leading and most valuable brands in the world, eBay has acquired iconic status on par with century-old brands such as Coca-Cola and Disney. The eBay logo is now synonymous with the world’s leading online auction website, and its design is associated with the company...

  5. Chesapeake Bay Watershed - Protecting the Chesapeake Bay and its rivers through science, restoration, and partnership

    Science.gov (United States)

    U.S. Geological Survey

    2012-01-01

    The Chesapeake Bay, the Nation's largest estuary, has been degraded due to the impact of human-population increase, which has doubled since 1950, resulting in degraded water quality, loss of habitat, and declines in populations of biological communities. Since the mid-1980s, the Chesapeake Bay Program (CBP), a multi-agency partnership which includes the Department of Interior (DOI), has worked to restore the Bay ecosystem. The U.S. Geological Survey (USGS) has the critical role of providing unbiased scientific information that is utilized to document and understand ecosystem change to help assess the effectiveness of restoration strategies in the Bay and its watershed. The USGS revised its Chesapeake Bay science plan for 2006-2011 to address the collective needs of the CBP, DOI, and USGS with a mission to provide integrated science for improved understanding and management of the Bay ecosystem. The USGS science themes for this mission are: Causes and consequences of land-use change; Impact of climate change and associated hazards; Factors affecting water quality and quantity; Ability of habitat to support fish and bird populations; and Synthesis and forecasting to improve ecosystem assessment, conservation, and restoration.

  6. Southern Monterey Bay Littoral Cell CRSMP Proposed Receiver Site 2008

    Data.gov (United States)

    California Department of Resources — Given the location of the critical areas of erosion and the need to avoid adverse impacts to local sensitive habitat, the Southern Monterey Bay Coastal RSM Plan...

  7. Impact of diabetes on cognitive function and brain structure.

    Science.gov (United States)

    Moheet, Amir; Mangia, Silvia; Seaquist, Elizabeth R

    2015-09-01

    Both type 1 and type 2 diabetes have been associated with reduced performance on multiple domains of cognitive function and with structural abnormalities in the brain. With an aging population and a growing epidemic of diabetes, central nervous system-related complications of diabetes are expected to rise and could have challenging future public health implications. In this review, we will discuss the brain structural and functional changes that have been associated with type 1 and type 2 diabetes. Diabetes duration and glycemic control may play important roles in the development of cognitive impairment in diabetes, but the exact underlying pathophysiological mechanisms causing these changes in cognition and structure are not well understood. Future research is needed to better understand the natural history and the underlying mechanisms, as well as to identify risk factors that predict who is at greatest risk of developing cognitive impairment. This information will lead to the development of new strategies to minimize the impact of diabetes on cognitive function. PMID:26132277

  8. Seasonal and Inter-Annual Patterns of Phytoplankton Community Structure in Monterey Bay, CA Derived from AVIRIS Data During the 2013-2015 HyspIRI Airborne Campaign

    Science.gov (United States)

    Palacios, S. L.; Thompson, D. R.; Kudela, R. M.; Negrey, K.; Guild, L. S.; Gao, B. C.; Green, R. O.; Torres-Perez, J. L.

    2015-12-01

    There is a need in the ocean color community to discriminate among phytoplankton groups within the bulk chlorophyll pool to understand ocean biodiversity, to track energy flow through ecosystems, and to identify and monitor for harmful algal blooms. Imaging spectrometer measurements enable use of sophisticated spectroscopic algorithms for applications such as differentiating among coral species, evaluating iron stress of phytoplankton, and discriminating phytoplankton taxa. These advanced algorithms rely on the fine scale, subtle spectral shape of the atmospherically corrected remote sensing reflectance (Rrs) spectrum of the ocean surface. As a consequence, these algorithms are sensitive to inaccuracies in the retrieved Rrs spectrum that may be related to the presence of nearby clouds, inadequate sensor calibration, low sensor signal-to-noise ratio, glint correction, and atmospheric correction. For the HyspIRI Airborne Campaign, flight planning considered optimal weather conditions to avoid flights with significant cloud/fog cover. Although best suited for terrestrial targets, the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has enough signal for some coastal chlorophyll algorithms and meets sufficient calibration requirements for most channels. However, the coastal marine environment has special atmospheric correction needs due to error that may be introduced by aerosols and terrestrially sourced atmospheric dust and riverine sediment plumes. For this HyspIRI campaign, careful attention has been given to the correction of AVIRIS imagery of the Monterey Bay to optimize ocean Rrs retrievals for use in estimating chlorophyll (OC3 algorithm) and phytoplankton functional type (PHYDOTax algorithm) data products. This new correction method has been applied to several image collection dates during two oceanographic seasons - upwelling and the warm, stratified oceanic period for 2013 and 2014. These two periods are dominated by either diatom blooms (occasionally

  9. The use of color infrared aerial photography in determining salt marsh vegetation and delimiting man-made structures of Lynnhaven Bay, Virginia. M.S. Thesis

    Science.gov (United States)

    Holman, R. E., III

    1974-01-01

    Color infrared aerial photography was found to be superior to color aerial photography in an ecological study of Lynnhaven Bay, Virginia. The research was divided into three phases: (1) Determination of the feasibility of correlating color infrared aerial photography with saline wetland species composition and zonation patterns, (2) determination of the accuracy of the aerial interpretation and problems related to the aerial method used; and (3) comparison of developed with undeveloped areas along Lynnhaven Bay's shoreline. Wetland species composition and plant community zonation bands were compared with aerial infrared photography and resulted in a high degree of correlation. Problems existed with changing physical conditions; time of day, aircraft angle and sun angle, making it necessary to use several different characteristics in wetland species identification. The main characteristics used were known zonation patterns, textural signatures and color tones. Lynnhaven Bay's shoreline was 61.5 percent developed.

  10. Structural footprinting in protein structure comparison: the impact of structural fragments

    Directory of Open Access Journals (Sweden)

    Wilbur W John

    2007-08-01

    Full Text Available Abstract Background One approach for speeding-up protein structure comparison is the projection approach, where a protein structure is mapped to a high-dimensional vector and structural similarity is approximated by distance between the corresponding vectors. Structural footprinting methods are projection methods that employ the same general technique to produce the mapping: first select a representative set of structural fragments as models and then map a protein structure to a vector in which each dimension corresponds to a particular model and "counts" the number of times the model appears in the structure. The main difference between any two structural footprinting methods is in the set of models they use; in fact a large number of methods can be generated by varying the type of structural fragments used and the amount of detail in their representation. How do these choices affect the ability of the method to detect various types of structural similarity? Results To answer this question we benchmarked three structural footprinting methods that vary significantly in their selection of models against the CATH database. In the first set of experiments we compared the methods' ability to detect structural similarity characteristic of evolutionarily related structures, i.e., structures within the same CATH superfamily. In the second set of experiments we tested the methods' agreement with the boundaries imposed by classification groups at the Class, Architecture, and Fold levels of the CATH hierarchy. Conclusion In both experiments we found that the method which uses secondary structure information has the best performance on average, but no one method performs consistently the best across all groups at a given classification level. We also found that combining the methods' outputs significantly improves the performance. Moreover, our new techniques to measure and visualize the methods' agreement with the CATH hierarchy, including the

  11. Coastal Habitat Restoration and Hydrodynamics in Panguil Bay, Philippines

    Science.gov (United States)

    Roxas, P. G.; Gorospe, J. G.

    2007-03-01

    Hydrobiological studies indicate the deterioration of the coastal ecosystems in Panguil Bay, Philippines despite interventions that started more than a decade ago. Mangrove ecosystems that filter land run offs and act as pollutant sinks are converted to fishponds that discharge toxic materials into the bay. Monsoon winds continue to erode mangrove-dominated coastlines. Water movements, nutrient transport and influx of freshwater from rivers and saline waters from the sea are altered by proliferating fishing structures and boats that use sea lanes for navigation. The reduction of current velocities increased siltation rates that caused shallowing of the bay. Failure in interventions to restore ecosystems is partly attributed to use of methods that failed to consider the bay's hydrodynamics. But sustaining the bay is a must because it is a major source of fishery resources hence strategies to arrest its further deterioration and to rehabilitate the degraded ecosystems based on the bay's hydrodynamics are explored. Timing, selection of appropriate species, and use of encasements are considered relative to the water dynamics of the bay. Zoning and regulation of barrier structures are implemented in some parts of the bay. Bioremediating agricultural run offs and discharges from fishponds, boats, and factories that accumulate in the inner part of the bay remains a challenge.

  12. Impact of structural characteristics on starch digestibility of cooked rice.

    Science.gov (United States)

    Tamura, Masatsugu; Singh, Jaspreet; Kaur, Lovedeep; Ogawa, Yukiharu

    2016-01-15

    To examine the impact of structural characteristics of cooked rice grains on their starch digestibility, a simulated in vitro gastro-small intestinal digestion technique was applied to intact and homogenised cooked rice samples. The starch hydrolysis percentage increased during simulated small intestinal digestion, in which approximately 65% and 24% of the starch was hydrolysed within the first 5min, for homogenised and intact cooked rice, respectively. The kinetic constant of homogenised cooked rice, which was regarded as an estimated digestion rate, was ∼8 times higher than the intact cooked rice. The homogenised and intact samples were also examined for any microstructural changes occurring during the in vitro digestion process using fluorescent and scanning electron microscopy. In the intact samples, the aleurone layers of the endosperm remained as thin-film like layers during in vitro digestion and thus may be regarded as less digestible materials that influence cooked rice digestibility. PMID:26258706

  13. Bohemian circular structure, Czechoslovakia: Search for the impact evidence

    Science.gov (United States)

    Rajlich, Petr

    1992-01-01

    Test of the impact hypothesis for the origin of the circular, 260-km-diameter structure of the Bohemian Massif led to the discovery of glasses and breccias in the Upper Proterozoic sequence that can be compared to autogeneous breccias of larger craters. The black recrystallized glass contains small exsolution crystals of albite-oligoclase and biotite, regularly dispersed in the matrix recrystallized to quartz. The occurrence of these rocks is limited to a 1-sq-km area. It is directly underlain by the breccia of the pelitic and silty rocks cemented by the melted matrix, found on several tens of square kilometers. The melt has the same chemistry as rock fragments in major and in trace elements. It is slightly impoverished in water. The proportion of melted rocks to fragments varies from 1:5 to 10:1. The mineralogy of melt viens is the function of later, mostly contact metamorphism. On the contact of granitic plutons it abounds on sillimanite, cordierite, and small bullets of ilmenite. Immediately on the contact with syenodiorites it contains garnets. The metamorphism of the impact rock melt seems the most probable explanation of the mineralogy and the dry total fusion of rocks accompanied by the strong fragmentation. Other aspects of this investigation are discussed.

  14. Impact of Corrugated Paperboard Structure on Puncture Resistance

    Directory of Open Access Journals (Sweden)

    Vaidas BIVAINIS

    2015-05-01

    Full Text Available Thanks to its excellent protective properties, lightness, a reasonable price, and ecology, corrugated paperboard is one of the most popular materials used in the production of packaging for various products. During transportation or storage, packaging with goods can be exposed to the mass of other commodities, dropping from heights and transportation shock loads, which can lead to their puncture damage. Depending on the purpose and size of the packaging, the thickness, grammage, constituent paper layers, numbers of layers and type of fluting of corrugated paperboard used in its production differ. A standard triangular prism, corrugated paperboard fixation plates and a universal tension-compression machine were used to investigate the impact of corrugated paperboard structure and other parameters on the puncture resistance of the material. The investigation determines the maximum puncture load and estimates energy required to penetrate the corrugated paperboard. It was found that the greatest puncture resistance is demonstrated by paperboard with a larger number of corrugating flutings and the board produced from harder paper with a smaller amount of recycled paper. It was established that the grammage of three-layered paperboard with two different fluting profiles has the greatest impact on the level of static puncture energy.

  15. Are there general spatial patterns of mangrove structure and composition along estuarine salinity gradients in Todos os Santos Bay?

    Science.gov (United States)

    Costa, Patrícia; Dórea, Antônio; Mariano-Neto, Eduardo; Barros, Francisco

    2015-12-01

    Species distribution and structural patterns of mangrove fringe forests along three tropical estuaries were evaluated in northeast of Brazil. Interstitial water salinity, percentage of fine sediments and organic matter content were investigated as explanatory variables. In all estuaries (Jaguaripe, Paraguaçu and Subaé estuaries), it was observed similar distribution patterns of four mangrove species and these patterns were mostly related with interstitial water salinity. Rhizophora mangle and Avicennia schaueriana tended to dominate sites under greater marine influence (lower estuary), while Avicennia germinans and Laguncularia racemosa dominated areas under greater freshwater influence (upper estuary), although the latter showed a wider distribution over these tropical estuarine gradients. Organic matter best explained canopy height and mean height. At higher salinities, there was practically no correlation between organic matter and density, but at lower salinity, organic matter was related to decreases in abundances. The described patterns can be related to interspecific differences in salt tolerance and competitive abilities and they are likely to be found at other tropical Atlantic estuaries. Future studies should investigate anthropic influences and causal processes in order to further improve the design of monitoring and restoration projects.

  16. Genetic population structure of polychaeta Neanthes glandicincta (Nereididae) of the Mai Po Inner Deep Bay Ramsar Site, Hong Kong.

    Science.gov (United States)

    Shen, Ping-Ping; Gu, Ji-Dong

    2015-10-01

    Neanthes glandicincta (Nereididae, Polychaeta) is the first numerically dominant benthic infauna in the Mai Po international Ramsar site, Hong Kong and also an economically important species for food source of birds and fishes. In present study, highly conserved nuclear ribosomal DNA (SSU and LSU rDNA) and mitochondrial COI gene were employed to study the population structure of N. glandicincta in the subtropical mudflat. The specimens were collected from five localities in February 2006, February-August 2007 and preserved at -80 °C, methanol or formalin, respectively. DNA extraction efficiency was the highest in fresh materials and lowest in formalin-fixed samples. The 18S (1774 bp), 28S D1 (383 bp) and COI genes were sequenced and analyzed. Both 18S and 28S D1 rDNA were highly conserved and showed no difference among the populations, whereas COI gene exhibited relatively high-level intraspecific polymorphism (2.2 %). The population from onshore and near mangrove station was phylogenetic different from other sites, indicating restricted gene exchange between the region of river mouth and mangrove forest. The mangrove may form a barrier for the dispersal of pelagic/benthic larvae of the population, which indicates that the population genetic difference is related to different habitats. PMID:25967938

  17. Characteristic mixing triangles in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.; Sastry, J.S.

    Temperature-salinity structures in the inner part of Bay of Bengal showed complete mixing processes in the upper bay, less than about 600 m can be characterisEd. by a mixing triangle constitutEd. by three characteristic water properties. In outer...

  18. Dyke emplacement at the incipient Namibian margin - structural and anisotropy of magnetic susceptibility (AMS) studies in the Henties Bay - Outjo Dyke Swarm

    Science.gov (United States)

    Wiegand, Miriam; Trumbull, Robert; Greiling, Reinhard O.

    2010-05-01

    During the Cretaceous breakup of western Gondwana, the conjugate Namibian and South American margins were the site of flood basalts, mafic dyke swarms and subvolcanic intrusive complexes which make up the South Atlantic Large Igneous Province and the volcanic margin of northwestern Namibia. This contribution presents data on internal fabrics in mafic dykes (mostly subalkaline tholeiitic dolerites) from the major Henties Bay-Outjo dyke swarm (HOD) in coastal and inland NW Namibia, which are discussed in terms of magma emplacement. The HOD is some 100 km wide and extends at least 500 km from the continental margin. The dykes were emplaced in Neoproterozoic (Panafrican) Damara mobile belt, which is bounded by the Angola/Congo craton on the north and the Kalahari craton on the south. Field relations and radiometric dates indicate Early Cretaceous emplacement ages for the dykes. In coastal exposures north of the HOD, dolerite dykes are mainly coast-parallel (NNW-SSE) and syn-tectonic with normal faults that offset Etendeka lavas. Coast-parallel dykes are also common within the HOD, but the great majority of dykes strike NE-SW. We observed the latter dykes to crosscut coast-parallel ones. But the opposite relationship is also found locally. The dominant NE-SW strike of HOD indicates the influence of the Damara Belt structural grain at a regional scale, but locally the dykes commonly crosscut basement foliations and lithologic contacts. Depending on dyke thickness, which varies in the HOD from a few cm to about 50 m), the dykes are variably fine grained with chilled margins. Vesiculation is seldom observed. Typical textures are intersertal to subophitic, with plagioclase, clinopyroxene and olivine being the main mineral phases. Common minor minerals include opaque oxides and acicular apatite. Linear dykes are composed of segments, 10 m to some km in length, which are connected by transfer zones. Often a minor horizontal displacement can be observed between these segments

  19. Environmental and Sanitary Conditions of Guanabara Bay, Rio de Janeiro.

    Science.gov (United States)

    Fistarol, Giovana O; Coutinho, Felipe H; Moreira, Ana Paula B; Venas, Tainá; Cánovas, Alba; de Paula, Sérgio E M; Coutinho, Ricardo; de Moura, Rodrigo L; Valentin, Jean Louis; Tenenbaum, Denise R; Paranhos, Rodolfo; do Valle, Rogério de A B; Vicente, Ana Carolina P; Amado Filho, Gilberto M; Pereira, Renato Crespo; Kruger, Ricardo; Rezende, Carlos E; Thompson, Cristiane C; Salomon, Paulo S; Thompson, Fabiano L

    2015-01-01

    Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km(2). In its surroundings live circa 16 million inhabitants, out of which 6 million live in Rio de Janeiro city, one of the largest cities of the country, and the host of the 2016 Olympic Games. Anthropogenic interference in Guanabara Bay area started early in the XVI century, but environmental impacts escalated from 1930, when this region underwent an industrialization process. Herein we present an overview of the current environmental and sanitary conditions of Guanabara Bay, a consequence of all these decades of impacts. We will focus on microbial communities, how they may affect higher trophic levels of the aquatic community and also human health. The anthropogenic impacts in the bay are flagged by heavy eutrophication and by the emergence of pathogenic microorganisms that are either carried by domestic and/or hospital waste (e.g., virus, KPC-producing bacteria, and fecal coliforms), or that proliferate in such conditions (e.g., vibrios). Antibiotic resistance genes are commonly found in metagenomes of Guanabara Bay planktonic microorganisms. Furthermore, eutrophication results in recurrent algal blooms, with signs of a shift toward flagellated, mixotrophic groups, including several potentially harmful species. A recent large-scale fish kill episode, and a long trend decrease in fish stocks also reflects the bay's degraded water quality. Although pollution of Guanabara Bay is not a recent problem, the hosting of the 2016 Olympic Games propelled the government to launch a series of plans to restore the bay's water quality. If all plans are fully implemented, the restoration of Guanabara Bay and its shores may be one of the best legacies of the Olympic Games in Rio de Janeiro. PMID:26635734

  20. Car Side Structure Crashworthiness in Pole and Moving Deformable Barrier Side Impacts

    Institute of Scientific and Technical Information of China (English)

    WANG Dazhi; DONG Guang; ZHANG Jinhuan; HUANG Shilin

    2006-01-01

    To clearly understand passenger car structure's crashworthiness in typical side impacts of pole and moving deformable barrier (MDB) impact modes, which could assist the establishment of Chinese vehicle side impact safety regulations, a full midsized car finite element model, calibrated by pole side impact test, was built and the pole side impact according to European New Car Assessment Program (EuroNCAP) and the MDB side impact according to ECE R95 regulations were simulated with LS-DYNA. The accelerations and the structure deformations from simulations were compared. It can be concluded that the pole side impact focuses primarily on side structure crashworthiness as a result of large intrusions, while the MDB side impact focuses primarily on full side structure crashworthiness. Accordingly, occupant protection strategies focus on different aspects to improve side impact safety. In the pole side impact the objective is to maintain the passenger compartment and protect the passenger's head from impacting the pole, while in the MDB side impact the objective is to protect the full human body. In the design of the car side structures, at least these two tests should be considered for assessing their side impact crashworthiness. Conducting these two side impact tests as certified tests provides insights into car safety during side impacts.

  1. Structural Safety Analysis on Drop Impact of Polymer Concrete Container

    International Nuclear Information System (INIS)

    Nuclear energy demand has been on the increase lately. In accordance with the demand, radioactive waste quantities have been increased continuously too. Consequently, the development of radioactive waste container to transport safe and store for a long time is a very important problem. But, the radioactive waste containers that have been developed by this time have generally been made of steel or polyethylene materials. These materials are so expensive and have a weakness of storing for a long time. Therefore, it has been substituted a polymer concrete material by steel and polyethylene to make up for these weaknesses recently. The radioactive waste container made of steel has been studied in domestic research work. Experimental study on Polymer concrete container reinforced steel structure was carried out lately. The radioactive waste container must be designed to ensure safe under all potential accidents. Especially, in case of drop accident under transporting, the radioactive waste container must be maintained integrity. In this work, a finite element analysis is carried out to evaluate structural safety on drop impact of polymer concrete container using ABAQUS explicit code

  2. Literature Review of Unconsolidated Sediment in San Francisco Bay and Nearby Pacific Ocean Coast

    OpenAIRE

    Keller, Barry R.

    2009-01-01

    A review of the geologic literature regarding sedimentation in the San Francisco Bay estuarine system shows that the main part of the bay occupies a structural tectonic depression that developed in Pleistocene time. Eastern parts, including San Pablo Bay and Suisun Bay, have had sedimentation throughout late Mesozoic and Tertiary. Carquinez Strait and the Golden Gate may represent antecedent stream erosion. Sedimentation has included estuarine, alluvial, and eolian deposition. The ages of est...

  3. Florida Bay: A history of recent ecological changes

    Science.gov (United States)

    Fourqurean, J.W.; Robblee, M.B.

    1999-01-01

    Florida Bay is a unique subtropical estuary at the southern tip of the Florida peninsula. Recent ecological changes (seagrass die-off, algal blooms, increased turbidity) to the Florida Bay ecosystem have focused the attention of the public, commercial interests, scientists, and resource managers on the factors influencing the structure and function of Florida Bay. Restoring Florida Bay to some historic condition is the goal of resource managers, but what is not clear is what an anthropogenically-unaltered Florida Bay would look like. While there is general consensus that human activities have contributed to the changes occurring in the Florida Bay ecosystem, a high degree of natural system variability has made elucidation of the links between human activity and Florida Bay dynamics difficult. Paleoecological analyses, examination of long-term datasets, and directed measurements of aspects of the ecology of Florida Bay all contribute to our understanding of the behavior of the bay, and allow quantification of the magnitude of the recent ecological changes with respect to historical variability of the system.

  4. Bathymetry in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 4x4 meter resolution bathymetric surface for Jobos Bay, Puerto Rico (in NAD83 UTM 19 North). The depth values are in meters referenced to...

  5. Hammond Bay Biological Station

    Data.gov (United States)

    Federal Laboratory Consortium — Hammond Bay Biological Station (HBBS), located near Millersburg, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). HBBS was established by...

  6. Logy Bay Fishing Settlement

    OpenAIRE

    S H Parsons and Sons

    2003-01-01

    202 x 151 mm. Showing the small inlet with moored rowing boats and rough wooden shacks built on the cliffside. Lying about seven miles from St. John's, Logy Bay was used as a summertime fishing station.

  7. Biscayne Bay Alongshore Epifauna

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Field studies to characterize the alongshore epifauna (shrimp, crabs, echinoderms, and small fishes) along the western shore of southern Biscayne Bay were started...

  8. Humboldt Bay Orthoimages

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of 0.5-meter pixel resolution, four band orthoimages covering the Humboldt Bay area. An orthoimage is remotely sensed image data in which...

  9. Understanding the Impact of Open-Framework Conglomerates on Water-Oil Displacements: Victor Interval of the Ivishak Reservoir, Prudhoe Bay Field, Alaska

    CERN Document Server

    Gershenzon, Naum I; Ritzi, Robert W; Dominic, David F

    2014-01-01

    The Victor Unit of the Ivishak Formation in the Prudhoe Bay Oilfield is characterized by high net-to-gross fluvial sandstones and conglomerates. The highest permeability is found within sets of cross-strata of open-framework conglomerate (OFC). They are preserved within unit bar deposits and assemblages of unit bar deposits within compound (braid) bar deposits. They are thief zones limiting enhanced oil recovery. We incorporate recent research that has quantified important attributes of their sedimentary architecture within preserved deposits. We use high-resolution models to demonstrate the fundamental aspects of their control on oil production rate, water breakthrough time, and spatial and temporal distribution of residual oil saturation. We found that when the pressure gradient is oriented perpendicular to the paleoflow direction, the total oil production and the water breakthrough time are larger, and remaining oil saturation is smaller, than when it is oriented parallel to paleoflow. The pressure differe...

  10. An On-Line Wireless Impact Monitoring System for Large Scale Composite Structures

    OpenAIRE

    Mei, Hanfei; Yuan, Shenfang; Qiu, Lei; Ren, Yuanqiang

    2014-01-01

    One of the major concerns in the whole lifetime of aircraft composite structures is their susceptibility to impact damage. Aiming at the impact monitoring of large scale composite structures, this paper puts forward an on-line wireless impact monitoring system based on a kind of wireless digital impact monitor developed. Different from traditional processing methods, the new one is fulfilled in a digital way by turning the outputs of PZT sensors directly into digital queues and localizing the...

  11. Comparison of Response between RC and SC Containment Structures Subjected to Aircraft Impact

    International Nuclear Information System (INIS)

    Since the aircraft terror to the World Trade Center (WTC) on September 11, 2001, an aircraft impact problem has been increasingly interested. The possibilities of aircraft impacts against nuclear power plants are one of important category. To date, the impact load of the analysis on aircraft impacts has been applied to target structures in local areas by using the impact force-time history function of Riera. However, Riera forcing function is not recommended at the expectation of unreasonable damage or perforation to target structures. The numerical analysis of rc and sc containment structures subjected to aircraft impact is performed by using the AUTODYN-3D. It is carried out the four different types for RC and SC structures. Thus, in this study, the different behaviors of containment structures and the safety of SC structure are expected

  12. Experimental Study and Numerical Simulation of Hypervelocity Projectile Impact on Double-Wall Structure

    Institute of Scientific and Technical Information of China (English)

    陈沿海; 张庆明; 黄风雷

    2004-01-01

    Tests of hypervelocity projectile impact on double-wall structure were performed with the front wall ranging from 0.5 mm to 2.0 mm thick and different impact velocities. Smooth particle hydrodynamics (SPH) code in LS-DYNA was employed for the simulation of hypervelocity impact on the double-wall structure. By using elementary shock wave theory, the experimental results above are analyzed. The analysis can provide an explanation for the penetration mechanism of hypervelocity projectile impact on double-wall structure about the effect of front wall thickness and impact velocity.

  13. Development of Time-Reversal Method for Impact Source Identification on Plate Structures

    OpenAIRE

    Chunlin Chen; Yulong Li; Fuh-Gwo Yuan

    2013-01-01

    This paper presents a detailed study on the impact source identification of a plate structure using time-reversal (T-R) method. Prior to impact monitoring, the plate is calibrated (or characterized) by transfer functions at discrete locations on the plate surface. Both impact location and impact loading time-history are identified using T-R technique and associated signal processing algorithms. Numerical verification for finite-size isotropic plates under low velocity impacts is performed to ...

  14. Impact of ATLAS measurements on the knowledge of proton structure

    CERN Document Server

    Gwenlan, Claire; The ATLAS collaboration

    2016-01-01

    Several measurements performed by the ATLAS collaboration can be used to constrain the proton structure. Measurements of the W+c production and the inclusive W and Z differential cross sections are found to constrain the poorly known strange-quark density at low x. Similarly, the ratio of W+/W- production is found to constrain the valence quarks at low x. New results will be presented using W,Z production at 13 TeV. New precise measurements of Drell-Yan cross section measurements performed above the Z peak region have a different sensitivity to parton flavour, parton momentum fraction x and scale Q compared to measurements on the Z peak. A large impact is found on the photon content of the proton as well as high x quarks. Measurements of the inclusive jet and photon cross sections are standard candles and constrain the medium and high x gluon densities. New precise measurements of inclusive photon and jet cross sections at 8 TeV are presented and compared to various PDF predictions.

  15. Impact of Corrugated Paperboard Structure on Puncture Resistance

    Directory of Open Access Journals (Sweden)

    Vaidas Bivainis

    2015-03-01

    Full Text Available Thanks to its excellentprotective properties, lightness, a reasonable price, and ecology, corrugated paperboardis one of the most popular materials used in the production of packaging for variousproducts. During transportation or storage, packaging with goods can be exposedto the mass of other commodities, dropping from heights and transportationshock loads, which can lead to their puncture damage. Depending on the purposeand size of the packaging, the thickness, grammage, constituent paper layers,numbers of layers and type of fluting of corrugated paperboard used in itsproduction differ. A standard triangular prism, corrugated paperboard fixationplates and a universal tension-compression machine were used to investigate theimpact of corrugated paperboard structure and other parameters on the punctureresistance of the material. The investigation determines the maximum punctureload and estimates energy required to penetrate the corrugated paperboard. Itwas found that the greatest puncture resistance is demonstrated by paperboardwith a larger number of corrugating flutings and the board produced from harderpaper with a smaller amount of recycled paper. It was established that thegrammage of three-layered paperboard with two different fluting profiles has thegreatest impact on the level of static puncture energy.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5713

  16. Impact of Demographic Structure on Paddy and Forestland Management

    Institute of Scientific and Technical Information of China (English)

    LI Tiehua; XIANG Wenhua; XU Guozhen; ZENG Guangzheng

    2006-01-01

    In order to understand the impact of demographic structure on paddy and forestland management after the convening of the Third Plenary Session of the 11"1 CPC (Communist Party of China) Central Committee and the implementation of the Household Responsibility System (the government divided up land among peasants for cultivating and the peasants sell a set part of their produced goods to the government at stipulated prices by contract in the countryside of China), 147 households in 6 villages, belonging to Xiangtan County and Zhuzhou County in Hunan Province, were selected as research samples, and interview, questionnaire survey and second hand data analyzing were used as the methods. The results showed: Persons with different ages had different ideas, and young peasants would like to work in towns or cities for more income, so they used and depended on land less; In terms of sex, the male was still the main user of land, and therefore the ability, idea and activity of male played an important role in land management; Generally, the labors with better educational background grasped more knowledge and technologies, and they had more opportunity to get jobs and had better working condition and more income in town or cities, so they depended on and used land less.

  17. Interannual variability and interdecadal trends in Hudson Bay streamflow

    Science.gov (United States)

    Déry, Stephen J.; Mlynowski, Theodore J.; Hernández-Henríquez, Marco A.; Straneo, Fiammetta

    2011-12-01

    This study investigates the interannual variability and interdecadal trends in streamflow input to Hudson Bay (including James Bay) over 1964-2008. The 23 rivers chosen for this study span a maximum gauged area of 2.54 × 10 6 km 2 and collectively transport 522 km 3 of freshwater to Hudson Bay each year. Adjusting this value for the missing contributing area yields a total annual freshwater flux of 760 km 3 into Hudson Bay. The standard deviation and coefficient of variation in annual streamflow to Hudson Bay reach 48.5 km 3 and 0.09, respectively. The monotonic trend assessed with a Kendall-Theil Robust Line shows no detectable (|signal-to-noise ratio| hydroelectricity in fall and winter. The naturally-flowing rivers show a marked decline in the variability of daily streamflow input to Hudson Bay in recent years while the opposite trend is found in the regulated systems. The fall 2009 diversion of 14.5 km 3 yr - 1 or 48% of the total annual streamflow from the Rupert River northward into La Grande Rivière for enhanced power production further exacerbates the streamflow timing shifts observed in Hudson Bay. The potential impacts of flow regulation on the Hudson Bay marine environment are then discussed.

  18. Variability and trends in streamflow input to Hudson Bay, Canada

    Science.gov (United States)

    Dery, Stephen; Mlynowski, Theodore; Hernandez-Henriquez, Marco; Straneo, Fiammetta

    2010-05-01

    This presentation will explore the variability and trend in streamflow input to Hudson Bay (including James Bay), Canada, over 1964-2008. Twenty-three rivers, spanning a maximum gauged area of 2.53 × 106 km2, are chosen for this study. These rivers collectively transport 521 km3 of freshwater to Hudson Bay each year. Adjusting this value for the missing contributing area yields a total annual freshwater flux of 762 km3 into Hudson Bay. The standard deviation and coefficient of variation in annual streamflow input to Hudson Bay reach 48.9 km3 and 0.09, respectively. The monotonic trend assessed with a Kendall-Theil Robust Line shows no detectable (|signal-to-noise ratio| hydroelectricity in fall and winter. The naturally-flowing rivers show a marked decline in the variability of daily streamflow input to Hudson Bay in recent years while the opposite trend is found in the regulated systems. The recent diversion of 19 km3 yr-1 or 71% of the annual streamflow from the Rupert River northward into La Grande Rivière for enhanced power production will further exacerbate the streamflow timing shifts observed in Hudson Bay. The talk will end with a brief discussion of the potential impacts of flow regulation on the Hudson Bay marine environment.

  19. Unheard voices: James Bay II and the women of Kuujjuarapik

    International Nuclear Information System (INIS)

    The attitudes held by the aboriginal peoples of the James Bay region toward the James Bay II hydroelectric power development are described. These attitudes are communicated primarily through the comments of Innu women. Major concerns with the Great Whale project relate to its impact on country food, mercury contamination, and camps. The entire community of Kuujjuarapik was totally opposed to the Great Whale project. While direct impacts such as mercury contamination or reduced wildlife harvest are the most obvious impacts, indirect impacts relating to cultural damage, increased abuse and alcoholism, and influx of non-native construction workers will also have significant effects, and warrant further study

  20. Core Perylene Diimide Designs via Direct Bay and Ortho (Poly)trifluoromethylation: Synthesis, Isolation, X-ray Structures, Optical and Electronic Properties

    Energy Technology Data Exchange (ETDEWEB)

    Clikeman, Tyler T.; Bukovsky, Eric V.; Wang, Xue B.; Chen, Yu-Sheng; Rumbles, Garry; Strauss, Steven H.; Boltalina, Olga V.

    2015-09-22

    We developed an efficient solvent- and catalyst-free direct polytrifluoromethylation of solid perylene-3,4,9,10-tetracarboxylic dianhydride that produced a new family of (poly)perfluoroalkyl bay and ortho substituted PDIs with two different imide substituents. Direct hydrogen substitution with CN group led to the synthesis of a cyanated perfluoroalkyl PDI derivative for the first time. Absorption, steady-state and time-resolved emission, X-ray diffraction, electrochemical, and gas-phase electron affinity data allowed for systematic studies of substitution effects at bay, ortho, and imide positions in the new PDIs. Solid-state packing showed remarkable variations in the intermolecular interactions that are important for charge transport and photophysical properties. Analysis of the electrochemical data for 143 electron poor PDIs, including newly reported compounds, revealed some general trends and peculiar effects of electron withdrawing group substitution at all three positions.

  1. Core Perylene Diimide Designs via Direct Bay- and ortho-(Poly)trifluoromethylation: Synthesis, Isolation, X-Ray Structures, Optical and Electronic Properties

    Energy Technology Data Exchange (ETDEWEB)

    Clikeman, Tyler T. [Colorado State Univ., Fort Collins, CO (United States); Bukovsky, Eric V. [Colorado State Univ., Fort Collins, CO (United States); Wang, Xue-Bin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chen, Yu-Sheng [Univ. of Chicago, IL (United States); Rumbles, Garry [National Renewable Energy Lab. (NREL), Golden, CO (United States); Strauss, Steven H. [Colorado State Univ., Fort Collins, CO (United States); Boltalina, Olga V. [Colorado State Univ., Fort Collins, CO (United States)

    2015-09-22

    We developed an efficient solvent- and catalyst-free direct polytrifluoromethylation of solid perylene-3,4,9,10-tetracarboxylic dianhydride that produced a new family of (poly)perfluoroalkyl bay- and ortho-substituted PDIs with two different imide substituents. Direct hydrogen substitution with CN group led to the synthesis of a cyanated perfluoroalkyl PDI derivative for the first time. Absorption, steady-state and time-resolved emission, X-ray diffraction, electrochemical, and gas-phase electron affinity data allowed for systematic studies of substitution effects at bay, ortho, and imide positions in the new PDIs. Solid-state packing showed remarkable variations in the intermolecular interactions that are important for charge transport and photophysical properties. Moreover, analysis of the electrochemical data for 143 electron poor PDIs, including newly reported compounds, revealed some general trends and peculiar effects from substituting electron-withdrawing groups at all three positions.

  2. Impact of the Medieval Climate Anomaly, Little Ice Age, and Recent Warming on Hydrology and Carbon Accumulation in the James Bay Lowland

    Science.gov (United States)

    Holmquist, J. R.; Booth, R. K.; MacDonald, G. M.

    2013-12-01

    Reconstructing late-Holocene hydroclimatic variations can be useful to understand the sensitivity of peatland soil carbon (C) to climate change (Bunbury et al., 2012). We reconstructed water table depth (WTD), using testate amoebae, for a four-core north to south transect of the James Bay Lowland and Boreal Shield of Ontario, Canada, and compared WTD to long-term apparent rate of C accumulation (LARCA). The three southern sites indicate that WTD fluctuated relative to the mean, with a wetter Medieval Climate Anomaly (MCA) and drier Little Ice Age (LIA) (Fig. 1). However, the most northern site recorded a wet LIA and dry MCA (Fig. 1). All four cores recorded drying coincident with modern warming (Fig. 1). Increased Medieval moisture detected in the three southern sites is consistent with a geographic pattern of precipitation anomalies associated with La Niña-like conditions, which cause drought in the American southwest and central plains regions coupled with increased moisture in the Pacific Northwest and north of the Great Lakes (Feng et al., 2008; Seager et al., 2008). Despite the hydroclimatic sensitivity of the region, we observed no consistent relationship between variations in WTD and LARCA from the same cores. At these particular sites, at least, C accumulation has not been sensitive to the range of climatic variability associated with the MCA, LIA and recent warming. Bunbury, J., Finkelstein, S. A., & Bollmann, J. (2012). Holocene hydro-climatic change and effects on carbon accumulation inferred from a peat bog in the Attawapiskat River watershed, Hudson Bay Lowlands, Canada. Quaternary Research: 275-284. Feng, S., Oglesby, R. J., Rowe, C. M., Loope, D. B., & Hu, Q. (2008). Atlantic and Pacific SST influences on Medieval drought in North America simulated by the Community Atmospheric Model. Journal of Geophysical Research: Atmospheres (1984-2012), 113(D11). Seager, R., Burgman, R., Kushnir, Y., Clement, A., Cook, E., Naik, N., & Miller, J. (2008). Tropical

  3. Searching for giant, ancient impact structures on Earth: The Mesoarchaean Maniitsoq structure, West Greenland

    Science.gov (United States)

    Garde, Adam A.; McDonald, Iain; Dyck, Brendan; Keulen, Nynke

    2012-07-01

    A 100 km-scale, circular region in the Archaean North Atlantic Craton centred at 65°15'N, 51°50'W near Maniitsoq town in West Greenland comprises a set of highly unusual geological features that were created during a single event involving intense crushing and heating and are incompatible with crustal orogenic processes. The presently exposed features of the Maniitsoq structure were buried 20-25 km below the surface when this event occurred at c. 3 Ga, during waning convergent orogeny. These features include: a large aeromagnetic anomaly; a central 35×50 km2 large area of comminuted quartzo-feldspathic material; regional-scale circular deformation; widespread random fractures with featherlike textures; intense fracture cleavage; amphibolite-granite-matrix breccias unrelated to faulting or intrusions; formation and common fluidisation of microbreccias; abundant evidence of direct K-feldspar and plagioclase melting superimposed on already migmatised rocks; deformation of quartz by slip; formation of planar elements in quartz and plagioclase; and, emplacement of crustally contaminated ultramafic intrusions and regional scale hydrothermal alteration under amphibolite-facies conditions. The diagnostic tools employed to identify impacting in the upper crust are inadequate for structures preserved deep within the continental crust. Nevertheless, the inferred scale, strain rates and temperatures necessary to create the Maniitsoq structure rule out a terrestrial origin of the structure.

  4. LLL/DOR seismic conservatism of operating plants project. Interm report on Task II. 1. 3: soil-structure interaction. Deconvolution of the June 7, 1975, Ferndale Earthquake at the Humboldt Bay Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Maslenikov, O.R.; Smith, P.D.

    1978-03-28

    The Ferndale Earthquake of June 7, 1975, provided a unique opportunity to study the accuracy of seismic soil-structure interaction methods used in the nuclear industry because, other than this event, there have been no cases of significant earthquakes for which moderate motions of nuclear plants have been recorded. Future studies are planned which will evaluate the soil-structure interaction methodology further, using increasingly complex methods as required. The first step in this task was to perform deconvolution and soil-structure interaction analyses for the effects of the Ferndale earthquake at the Humboldt Bay Power Plant site. The deconvolution analyses of bedrock motions performed are compared as well as additional studies on analytical sensitivity.

  5. LLL/DOR seismic conservatism of operating plants project. Interm report on Task II.1.3: soil-structure interaction. Deconvolution of the June 7, 1975, Ferndale Earthquake at the Humboldt Bay Power Plant

    International Nuclear Information System (INIS)

    The Ferndale Earthquake of June 7, 1975, provided a unique opportunity to study the accuracy of seismic soil-structure interaction methods used in the nuclear industry because, other than this event, there have been no cases of significant earthquakes for which moderate motions of nuclear plants have been recorded. Future studies are planned which will evaluate the soil-structure interaction methodology further, using increasingly complex methods as required. The first step in this task was to perform deconvolution and soil-structure interaction analyses for the effects of the Ferndale earthquake at the Humboldt Bay Power Plant site. The deconvolution analyses of bedrock motions performed are compared as well as additional studies on analytical sensitivity

  6. Méthodes bayésiennes en génétique des populations : relations entre structure génétique des populations et environnement

    OpenAIRE

    Jay, Flora

    2011-01-01

    Nous présentons une nouvelle méthode pour étudier les relations entre la structure génétique des populations et l'environnement. Cette méthode repose sur des modèles hiérarchiques bayésiens qui utilisent conjointement des données génétiques multi-locus et des données spatiales, environnementales et/ou culturelles. Elle permet d'estimer la structure génétique des populations, d'évaluer ses liens avec des covariables non génétiques, et de projeter la structure génétique des populations en fonct...

  7. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors

    OpenAIRE

    Si, Liang; Baier, Horst

    2015-01-01

    For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. ...

  8. Impact of oil on bacterial community structure in bioturbated sediments.

    Directory of Open Access Journals (Sweden)

    Magalie Stauffert

    Full Text Available Oil spills threaten coastlines where biological processes supply essential ecosystem services. Therefore, it is crucial to understand how oil influences the microbial communities in sediments that play key roles in ecosystem functioning. Ecosystems such as sediments are characterized by intensive bioturbation due to burrowing macrofauna that may modify the microbial metabolisms. It is thus essential to consider the bioturbation when determining the impact of oil on microbial communities. In this study, an experimental laboratory device maintaining pristine collected mudflat sediments in microcosms closer to true environmental conditions--with tidal cycles and natural seawater--was used to simulate an oil spill under bioturbation conditions. Different conditions were applied to the microcosms including an addition of: standardized oil (Blend Arabian Light crude oil, 25.6 mg.g⁻¹ wet sediment, the common burrowing organism Hediste (Nereis diversicolor and both the oil and H. diversicolor. The addition of H. diversicolor and its associated bioturbation did not affect the removal of petroleum hydrocarbons. After 270 days, 60% of hydrocarbons had been removed in all microcosms irrespective of the H. diversicolor addition. However, 16S-rRNA gene and 16S-cDNA T-RFLP and RT-PCR-amplicon libraries analysis showed an effect of the condition on the bacterial community structure, composition, and dynamics, supported by PerMANOVA analysis. The 16S-cDNA libraries from microcosms where H. diversicolor was added (oiled and un-oiled showed a marked dominance of sequences related to Gammaproteobacteria. However, in the oiled-library sequences associated to Deltaproteobacteria and Bacteroidetes were also highly represented. The 16S-cDNA libraries from oiled-microcosms (with and without H. diversicolor addition revealed two distinct microbial communities characterized by different phylotypes associated to known hydrocarbonoclastic bacteria and dominated by

  9. Impact of oil on bacterial community structure in bioturbated sediments.

    Science.gov (United States)

    Stauffert, Magalie; Cravo-Laureau, Cristiana; Jézéquel, Ronan; Barantal, Sandra; Cuny, Philippe; Gilbert, Franck; Cagnon, Christine; Militon, Cécile; Amouroux, David; Mahdaoui, Fatima; Bouyssiere, Brice; Stora, Georges; Merlin, François-Xavier; Duran, Robert

    2013-01-01

    Oil spills threaten coastlines where biological processes supply essential ecosystem services. Therefore, it is crucial to understand how oil influences the microbial communities in sediments that play key roles in ecosystem functioning. Ecosystems such as sediments are characterized by intensive bioturbation due to burrowing macrofauna that may modify the microbial metabolisms. It is thus essential to consider the bioturbation when determining the impact of oil on microbial communities. In this study, an experimental laboratory device maintaining pristine collected mudflat sediments in microcosms closer to true environmental conditions--with tidal cycles and natural seawater--was used to simulate an oil spill under bioturbation conditions. Different conditions were applied to the microcosms including an addition of: standardized oil (Blend Arabian Light crude oil, 25.6 mg.g⁻¹ wet sediment), the common burrowing organism Hediste (Nereis) diversicolor and both the oil and H. diversicolor. The addition of H. diversicolor and its associated bioturbation did not affect the removal of petroleum hydrocarbons. After 270 days, 60% of hydrocarbons had been removed in all microcosms irrespective of the H. diversicolor addition. However, 16S-rRNA gene and 16S-cDNA T-RFLP and RT-PCR-amplicon libraries analysis showed an effect of the condition on the bacterial community structure, composition, and dynamics, supported by PerMANOVA analysis. The 16S-cDNA libraries from microcosms where H. diversicolor was added (oiled and un-oiled) showed a marked dominance of sequences related to Gammaproteobacteria. However, in the oiled-library sequences associated to Deltaproteobacteria and Bacteroidetes were also highly represented. The 16S-cDNA libraries from oiled-microcosms (with and without H. diversicolor addition) revealed two distinct microbial communities characterized by different phylotypes associated to known hydrocarbonoclastic bacteria and dominated by Gammaproteobacteria

  10. ENSO and anthropogenic impacts on phytoplankton diversity in tropical coastal waters

    Science.gov (United States)

    Doan-Nhu, Hai; Nguyen-Ngoc, Lam; Nguyen, Chi-Thoi

    2016-01-01

    16-year phytoplankton data were analysed to assess ENSO and anthropogenic impacts on biodiversity and community structure at 3 locations (Nha-Trang and Phan-Thiet Bays and near Phu-Qui Island) in South Centre Viet Nam to understand (1) the primary scales of change in phytoplankton community structure, and traditional and taxonomic diversity indices; (2) the significance of environmental changes and/or climate variability on phytoplankton diversity; and (3) the usefulness of these long-term data for analysing future impacts of anthropogenic and climate changes. Traditional and taxonomic diversity indices were compared and tested in linkage with environmental conditions and ENSO. Nutrient data indicated stronger environmental impacts in Phan-Thiet Bay, milder in Nha-Trang Bay and less noticeable near Phu-Qui Island. There were measurable impacts of both anthropogenic and ENSO on phytoplankton at different locations in various parameters, e.g. species number, diversity and community structures. The lowest diversity was recorded in the most anthropogenically impacted site, Phan-Thiet Bay. Although a stronger impact on phytoplankton was recorded in ENSO year in Phan Thiet Bay, quantitative separation between anthropogenic and ENSO impacts using phytoplankton biodiversity indices was impossible. In the waters with less anthropogenic impacts, ENSO effects on taxonomic diversity was better indicated by negative phytoplankton responses to the ONI index (Nha-Trang Bay) and recovery of phytoplankton after the ENSO events (near Phu-Qui Island). Among the diversity indices, the taxonomic diversity indices (e.g. Δ+ and Λ+) better described impacts of ENSO than the traditional ones.

  11. Effect of environmental impact to molecular expression of heat-shock protein (HSP70) in oyster Crassostrea gigas from Gamak bay, Korea.

    Science.gov (United States)

    Cho, Eun-Seob; Jeong, Hee-Dong

    2012-05-01

    The cDNA of Crassostrea gigas HSP70 was cloned and rapid amplification of cDNA (RACE) techniques were used. The full length of HSP70 cDNA was 2045 bp, consisting of a 5' terminal untranslated region (UTR) of 80 bp, a 3' terminal UTR 146 bp, and an open reading frame (ORF) of 1829 bp encoding deduced 620 amino acids. The HSP70 cDNA contained HSP70 family signatures, ATP-GTP binding site motif, tetrapeptide (GGMP) and conserved carboxyl terminal region (EEVD) at C-terminal of deduced amino acid sequence. BLAST analysis revealed that the HSP70 gene has an extreme similarity of 98.9% with C. gigas (AF144646). Northern blotting was used to examine the expression of HSP70 mRNA in the gill tissue of the oyster obtained from surface, middle and bottom layers. The HSP70 mRNA observed the samples taken from middle and bottom layers in September and February, but samples from the surface layer did not find a signal intensity of HSP70 mRNA transcript. Consequently, it seems that the oyster occurring middle and bottom layer have been stressed during the period of summer and winter, which is associated with the massive mortality in Gamak bay. PMID:23029911

  12. Monte Carlo Simulations of Impact Ionization Feedback in MOSFET Structures

    OpenAIRE

    Bude, Jeff D.

    1998-01-01

    Although impact ionization feedback is recognized as an important current multiplication mechanism, its importance as a carrier heating mechanism has been largely overlooked. This work emphasizes the inclusion of impact ionization feedback in Monte Carlo device simulations, and its implications for carrier heating in sub-micron CMOS and EEPROM technologies.

  13. The impact of the Journal of Homotopy and Related Structures

    Czech Academy of Sciences Publication Activity Database

    Markl, Martin

    2014-01-01

    Roč. 9, č. 1 (2014), s. 7-8. ISSN 2193-8407 Institutional support: RVO:67985840 Keywords : impact * homotopy * homology Subject RIV: BA - General Mathematics Impact factor: 0.571, year: 2014 http://link.springer.com/article/10.1007/s40062-013-0056-1

  14. Probability of Detection Study on Impact Damage to Honeycomb Composite Structure using Thermographic Inspection

    Science.gov (United States)

    Hodge, Andrew J.; Walker, James L., II

    2008-01-01

    A probability of detection study was performed for the detection of impact damage using flash heating infrared thermography on a full scale honeycomb composite structure. The honeycomb structure was an intertank structure from a previous NASA technology demonstration program. The intertank was fabricated from IM7/8552 carbon fiber/epoxy facesheets and aluminum honeycomb core. The intertank was impacted in multiple locations with a range of impact energies utilizing a spherical indenter. In a single blind study, the intertank was inspected with thermography before and after impact damage was incurred. Following thermographic inspection several impact sites were sectioned from the intertank and cross-sectioned for microscopic comparisons of NDE detection and actual damage incurred. The study concluded that thermographic inspection was a good method of detecting delamination damage incurred by impact. The 90/95 confidence level on the probability of detection was close to the impact energy that delaminations were first observed through cross-sectional analysis.

  15. The Fermi's Bayes Theorem

    CERN Document Server

    D'Agostini, G

    2005-01-01

    It is curious to learn that Enrico Fermi knew how to base probabilistic inference on Bayes theorem, and that some influential notes on statistics for physicists stem from what the author calls elsewhere, but never in these notes, {\\it the Bayes Theorem of Fermi}. The fact is curious because the large majority of living physicists, educated in the second half of last century -- a kind of middle age in the statistical reasoning -- never heard of Bayes theorem during their studies, though they have been constantly using an intuitive reasoning quite Bayesian in spirit. This paper is based on recollections and notes by Jay Orear and on Gauss' ``Theoria motus corporum coelestium'', being the {\\it Princeps mathematicorum} remembered by Orear as source of Fermi's Bayesian reasoning.

  16. Reaction-time relationship and structural design of reinforced concrete slabs and shells for aircraft impact

    International Nuclear Information System (INIS)

    This paper outlines a rational procedure by which reinforced concrete structures such as slabs and shells may be designed to retain the required structural integrity after an aircraft impact. The paper presents a new estimate of the reaction-time relationship for impacting aircraft. A new estimate of the punching shear capacity is proposed. In addition, a simple, rotational design procedure is presented. (Auth.)

  17. Cracking associated with micrometeoroid impact craters in anodized aluminum alloy clamps on LDEF

    Science.gov (United States)

    Murr, Lawrence E.; Niou, Chorng S.; Quinones, Stella; Murr, Kyle S.

    1992-01-01

    The Long Duration Exposure Facility (LDEF) is a reusable hollow-cylindrical satellite sustaining a total of 57 different experiments. The 130 sq m of spacecraft surface area included anodized 6061-T6 Al alloy bay frames and clamps for holding experiment trays in the bay areas. Attention is presently given to the micrometeoroid impact crater features observed on two tray clamps recovered from the LDEF leading-edge locations. It is found that even very subtle surface modifications in structural alloy anodizing can influence micrometeoroid impact crater cracking, notable radial cracking due to the ejecta-rim of the impact craters.

  18. Humic Substances from Manila Bay and Bolinao Bay Sediments

    OpenAIRE

    Elma Llaguno

    1997-01-01

    The C,H,N composition of sedimentary humic acids (HA) extracted from three sites in Manila Bay and six sites in Bolinao Bay yielded H/C atomic ratios of 1.1-1.4 and N/C atomic ratios of 0.09 - 0.16. The Manila Bay HA's had lower H/C and N/C ratios compared to those from Bolinao Bay. The IR spectra showed prominent aliphatic C-H and amide I and II bands. Manila Bay HA's also had less diverse molecular composition based on the GC-MS analysis of the CuO and alkaline permanganate oxidation produc...

  19. Humic substances from Manila Bay and Bolinao Bay sediments

    International Nuclear Information System (INIS)

    The C, H, N composition of sedimentary humic acids (HA) extracted from three sites in Manila Bay and six sites in Bolinao Bay yielded H/C atomic ratios of 1.1-1.4 and N/C atomic ratios of 0.09-0.16. The Manila Bay HA's had lower H/C and C/C ratios compared to those from Bolinao Bay. The IR spectra showed prominent aliphatic C-H amide I and II bands. Manila Bay HA's also had less diverse molecular composition based on the GC-MS analysis of the CuO and alkaline permanganate oxidation products of the humic acids. (Author)

  20. Monterey Bay geoid

    OpenAIRE

    Boener, Joseph H.

    1994-01-01

    A high resolution local geoid was calculated for the Monterey Bay, CA using local gravimetry data, digital elevation data and The Ohio State University OSU91A global geopotential model. The theoretical accuracy of the calculated local geoid is 3.5 cm or better over 5 km. Local gravity data came from three sources: 1,549 land observations from the Defense Mapping Agency, 179 bottom gravity observations from two Naval Postgraduate School gravity surveys of Monterey Bay and 17,098 National Geode...

  1. Impact of Sundarban mangrove biosphere on the carbon dioxide and methane mixing ratios at the NE Coast of Bay of Bengal, India

    International Nuclear Information System (INIS)

    Diurnal and seasonal variations in carbon dioxide and methane fluxes between Sundarban biosphere and atmosphere were measured using micrometeorological method during 1998-2000. Study of the diurnal variation of micrometeorological conditions in the atmosphere was found to be necessary to determine the duration of neutral stability when flux estimation was reliable. Neutral stability of the atmosphere occurred in the limited micrometeorological conditions, when friction velocity ranged between 0.360 and 0.383ms-1. The value of drag coefficient (1.62-20.6) x 103 obtained at variable wind speed could be deemed specific for this particular surface. 58.2% drop of carbon dioxide and 63.4% drop of methane in the atmosphere at 1m height were observed during day time, between dawn and early evening. Diurnal variations in methane and carbon dioxide mixing ratios showed a positive correlation with Richardson's number (Ri). This environment acted as a net source for carbon dioxide and methane. The mixing ratios of methane were found to vary between 1.42 and 2.07ppmv, and that of carbon dioxide, between 324.3 and 528.7ppmv during the study period. The biosphere-atmosphere flux of carbon dioxide ranged between -3.29 and 34.4mgm-2s-1, and that of methane, between -4.53 and 8.88μgm-2s-1. The overall annual estimate of carbon dioxide and methane fluxes from this ecosystem to atmosphere were estimated to be 694Tgyr-1 and 184Ggyr-1, respectively. Considerable variations in mixing ratios of carbon dioxide and methane at the NE coast of Bay of Bengal were observed due to the seasonal variations of their fluxes from the biosphere to the atmosphere. The composition was inferred by fitting model prediction to measurements. (Author)

  2. Nutrients, heavy metals and phthalate acid esters in solar greenhouse soils in Round-Bohai Bay-Region, China: impacts of cultivation year and biogeography.

    Science.gov (United States)

    Chen, Zhiqun; Tian, Tian; Gao, Lihong; Tian, Yongqiang

    2016-07-01

    Solar greenhouse is a common facility type used for horticultural crop production in China. However, most solar greenhouse fields have been degraded due to continuous cropping and excessive fertilizer use. Therefore, we investigated solar greenhouse soils covering a wide range of cultivation years and environmental conditions in Round-Bohai Bay-Region to test the effects of cultivation year and biogeography on nutrients, heavy metals, and phthalate acid esters (PAEs). In general, soil pH decreased while soil electrical conductivity (EC), organic matter (OM), total nitrogen (TN), NO3 (-)-N, NH4 (+)-N, mineral nitrogen (MN), Olsen-P, and NH4OAc-K contents increased as time of cultivation increased. However, this trend was influenced by sampling sites. Among sampling sites, Jiangsu showed a relatively low soil pH and high Olsen-P content, while Hebei showed a relatively high soil EC value, NO3 (-)-N, NH4 (+)-N, MN, and NH4OAc-K contents. Liaoning was characterized by relatively high soil OM and TN contents. The nutrient level indexes in evaluation of soil quality on Olsen-P and NH4OAc-K exceeded the standard seriously. The maximum values of the heavy metals Cd, Cu, and Zn were 4.87, 2.78, and 1.15 times higher than the threshold values, respectively. There was a rising trend on the heavy metal contents with the increasing cultivation years, and this trend was significantly influenced by sampling sites. Both Cu and Zn had relative high heavy metal indexes in evaluation of soil pollution. The PAEs were not detected in almost all sampling soils. Overall, the excessive fertilizer application was an important cause of nutrient accumulation and heavy metal pollution, resulting in soil degradation in solar greenhouses. PMID:26996919

  3. Rising sea level, temperature, and precipitation impact plant and ecosystem responses to elevated CO2 on a Chesapeake Bay wetland: review of a 28-year study.

    Science.gov (United States)

    Drake, Bert G

    2014-11-01

    An ongoing field study of the effects of elevated atmospheric CO2 on a brackish wetland on Chesapeake Bay, started in 1987, is unique as the longest continually running investigation of the effects of elevated CO2 on an ecosystem. Since the beginning of the study, atmospheric CO2 increased 18%, sea level rose 20 cm, and growing season temperature varied with approximately the same range as predicted for global warming in the 21st century. This review looks back at this study for clues about how the effects of rising sea level, temperature, and precipitation interact with high atmospheric CO2 to alter the physiology of C3 and C4 photosynthetic species, carbon assimilation, evapotranspiration, plant and ecosystem nitrogen, and distribution of plant communities in this brackish wetland. Rising sea level caused a shift to higher elevations in the Scirpus olneyi C3 populations on the wetland, displacing the Spartina patens C4 populations. Elevated CO2 stimulated carbon assimilation in the Scirpus C3 species measured by increased shoot and root density and biomass, net ecosystem production, dissolved organic and inorganic carbon, and methane production. But elevated CO2 also decreased biomass of the grass, S. patens C4. The elevated CO2 treatment reduced tissue nitrogen concentration in shoots, roots, and total canopy nitrogen, which was associated with reduced ecosystem respiration. Net ecosystem production was mediated by precipitation through soil salinity: high salinity reduced the CO2 effect on net ecosystem production, which was zero in years of severe drought. The elevated CO2 stimulation of shoot density in the Scirpus C3 species was sustained throughout the 28 years of the study. Results from this study suggest that rising CO2 can add substantial amounts of carbon to ecosystems through stimulation of carbon assimilation, increased root exudates to supply nitrogen fixation, reduced dark respiration, and improved water and nitrogen use efficiency. PMID:24820033

  4. Finite element analysis of the impact response of reinforced concrete structures using DYNA3D

    International Nuclear Information System (INIS)

    Reinforced concrete structures in nuclear installations are potentially subject to accidental impact from external or internally generated hazards. These include: soft impacts such as aircraft crash on containment structures; and hard impacts such as heavy dropped loads on pond floors, or plant-generated fragments on structural and protective walls. The explicit finite element code DYNA3D has been used extensively for analysis of the response of structures to dynamic loadings, and a constitutive material model for reinforced concrete has been developed within DYNA3D to represent local cracking and crushing due to impact loads, as well as treating the elastic and plastic global response modes of the structure. This model has been extensively validated against impact tests for simulated aircraft impact on containment structures, but more recent interest has concentrated on analysis of hard impacts on floors and walls. Whilst a simplified constitutive model is adequate for the response to soft impacts, in which the dominant response mode is flexural, the local damage and high rates experienced in hard impacts have required further development of the material model. This paper describes the main features of the constitutive model, and presents the results of a validation case of a heavy dropped load on a reinforced concrete floor. (author)

  5. Phytoplankton Communities in Green Bay, Lake Michigan after Invasion by Dreissenid Mussels: Increased Dominance by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Bart T. De Stasio

    2014-11-01

    Full Text Available Biological invasions of aquatic systems disrupt ecological communities, and cause major changes in diversity and ecosystem function. The Laurentian Great Lakes of North America have been dramatically altered by such invasions, especially zebra (Dreissena polymorpha and quagga (D. rostriformis bugensis mussels. Responses to mussel invasions have included increased water clarity, and decreased chlorophyll and phytoplankton abundance. Although not all systems have responded similarly, in general, mussels have changed nutrient dynamics and physical habitat conditions. Therefore examination of different impacts can help us further understand mechanisms that underlie ecosystem responses to biological invasions. To aid our understanding of ecosystem impacts, we sampled established locations along a well-studied trophic gradient in Green Bay, Lake Michigan, after the 1993 zebra mussel invasion. A strong trophic gradient remained during the period sampled after the mussel invasion (2000–2012. However, mean summer chlorophyll increased and other measures of phytoplankton biomass (microscope and electronic cell counting did not change significantly. Multivariate analyses of phytoplankton community structure demonstrate a significant community shift after the invasion. Cyanobacteria increased in dominance, with Microcystis becoming the major summer taxon in lower Green Bay. Diatom diversity and abundance also increased and Chlorophyta became rare. Phytoplankton responses along the trophic gradient of Green Bay to zebra mussel invasion highlight the importance of mussel effects on nutrient dynamics and phytoplankton diversity and function.

  6. Benthic community structure in the Gorgan Bay (Southeast of the Caspian Sea, Iran: Correlation to water physiochemical factors and heavy metal concentration of sediment

    Directory of Open Access Journals (Sweden)

    Mahmood Saghali

    2013-11-01

    Full Text Available Macrobentos frequency and biomass was investigated in the Gorgan Bay in 2011. Five sampling sites were chosen to collect benthos and sediment from the Bay using a Van Veen grab sampler. Samples were collected seasonally. Macrobenthos were indentified and their biomass was recorded. Sediment heavy metals concentration were measured using Atomic Absorption Spectroscopy. A total of 11 families belonging to three phyla of invertebrates were found. The phyla were Annelids (Nereidae, Naididae, Ampharetidae, Lumbriculidae, Tubificidae and Amphiporidae, Arthropods (Pontogammaridae, Balanidae and Chironomidae and Mollusks (Cardiidae and Scrobicularidae. Lumbriculidae (413 individuals m-2, corresponding to 18.7% and Cardiidae (55.2 g m-2, corresponding to 82.4% had the highest frequency and biomass, respectively. Annelids with an average of 1557 individuals m-2 was the most frequent groups, while, mollusks with the average of 141 g per m2 had the highest biomass. Results showed that macrobenthos frequency in summer was significantly higher than those of the other seasons, however, in the case of biomass, there was a significantly higher biomass in the spring than the other seasons. The maximum metal concentration was related to Zn and Pb, whereas, Cr and Cd had the lowest values. There was no significant difference in Zn and Cr concentrations among the sampling seasons. Pb concentration in winter was significantly lower than the other seasons, whereas, Cd concentrations in the spring and summer were significantly lower than the autumn and winter. There were some correlations between benthos frequency and water physiochemical characteristics and sediment heavy metal levels. This study indicated that benthic fauna of the Gorgan Bay and the Caspian Sea are not similar. Also, results showed that benthic fauna communities are affected by sediment heavy metal concentrations and water physiochemical characteristics, however, different benthos groups show

  7. Impact loaded reinforced concrete structures, numerical and experimental studies

    International Nuclear Information System (INIS)

    Conclusions:In order to simulate realistically dynamic behaviour of an impact loaded reinforced concrete slab, all the material behaviour should be modelled strain rate dependent. However, in a real scale case, considering a passenger aircraft crashing to a containment building, the strain rates in reinforced concrete wall are probably lower than those observed during the impact tests. Experimental research is needed to obtain relevant data for numerical analyses. Also numerical methods and models need further development

  8. Modelling Impact Damage in Sandwich Structures with Folded Composite Cores

    OpenAIRE

    Johnson, Alastair; Kilchert, Sebastian

    2010-01-01

    The paper describes FE simulation methods for novel folded structural composite cores being developed for sandwich structures with enhanced performance for use in aircraft fuselage and wing primary structures. To support these materials and structural developments, computational methods were developed in the EU project CELPACT based on micromechanics cell models of the core with multiscale FE modelling techniques for understanding progressive damage and collapse mechanisms. The paper discusse...

  9. Bayes linear variance adjustment for time series

    CERN Document Server

    Wilkinson, Darren J

    2008-01-01

    This paper exhibits quadratic products of linear combinations of observables which identify the covariance structure underlying the univariate locally linear time series dynamic linear model. The first- and second-order moments for the joint distribution over these observables are given, allowing Bayes linear learning for the underlying covariance structure for the time series model. An example is given which illustrates the methodology and highlights the practical implications of the theory.

  10. Some challenges of an 'upside down' nitrogen budget - Science and management in Greenwich Bay, RI (USA)

    International Nuclear Information System (INIS)

    Research highlights: → Nutrient budget found most nitrogen to Greenwich Bay, RI is from adjacent estuary. → Water, plants, and animals in Greenwich Bay all have similar high stable isotope values. → Flux weighted isotope budgets find 50-80% of nitrogen in clams from adjacent bay. - Abstract: When nutrients impact estuarine water quality, scientists and managers instinctively focus on quantifying and controlling land-based sources. However, in Greenwich Bay, RI, the estuary opens onto a larger and more intensively fertilized coastal water body (Narragansett Bay). Previous inventories of nitrogen (N) inputs to Greenwich Bay found that N inputs from Narragansett Bay exceeded those from the local watershed, suggesting that recent efforts to reduce local watershed N loads may have little effect on estuarine water quality. We used stable isotopes of N to characterize watershed and Narragansett Bay N sources as well as the composition of primary producers and consumers throughout Greenwich Bay. Results were consistent with previous assessments of the importance of N inputs to Greenwich Bay from Narragansett Bay. As multiple N sources contribute to estuarine water quality, effective management requires attention to individual sources commensurate with overall magnitude, regardless of the political complications that may entail.

  11. Environmental and sanitary conditions of Guanabara Bay, Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Giovana De Oliveira Fistarol

    2015-11-01

    Full Text Available Guanabara Bay is the second largest bay in the coast of Brazil, with an area of 384 km2. In its surroundings live circa 16 million inhabitants, out of which 6 million live in Rio de Janeiro city, one of the largest cities of the country, and the host of the 2016 Olympic Games. Anthropogenic interference in Guanabara Bay area started early in the XVI century, but environmental impacts escalated from 1930, when this region underwent an industrialization process. Herein we present an overview of the current environmental and sanitary conditions of Guanabara Bay, a consequence of all these decades of impacts. We will focus on microbial communities, how they may affect higher trophic levels of the aquatic community and also human health. The anthropogenic impacts in the bay are flagged by heavy eutrophication and by the emergence of pathogenic microorganisms that are either carried by domestic and/or hospital waste (e.g. virus, KPC-producing bacteria, and fecal coliforms, or that proliferate in such conditions (e.g. vibrios. Antibiotic resistance genes are commonly found in metagenomes of Guanabara Bay planktonic microorganisms. Furthermore, eutrophication results in recurrent algal blooms, with signs of a shift towards flagellated, mixotrophic groups, including several potentially harmful species. A recent large-scale fish kill episode, and a long trend decrease in fish stocks also reflects the bay’s degraded water quality. Although pollution of Guanabara Bay is not a recent problem, the hosting of the 2016 Olympic Games propelled the government to launch a series plans to restore the bay’s water quality. If all plans are fully implemented, the restoration of Guanabara Bay and its shores may be one of the best legacies of the Olympic Games in Rio de Janeiro.

  12. Jog Structures at Both Ends of the Tepetarla Segment Ruptured as the First Subevent of the 1999 Izmit Earthquakes, Turkey, Revealed by Acoustic Surveys in the Izmit Bay and the Sapanca Lake

    Science.gov (United States)

    Awata, Y.; Okamura, M.; Matsuoka, H.; Ozalp, S.; Kinjo, S.; Tokay, F.; Dogan, A.; Emre, O.; Kuscu, I.

    2002-12-01

    Size and geometry of jogs among fault segments play important roles in rupture propagation during large earthquakes. We carried out a very detail acoustic survey around the both ends of the Tepetarla (Sapanca) segment, which ruptured as the first sub-event of the 1999 Izmit earthquakes of Mw7.4, in the Izmit Bay and the Sapanca Lake, using a very high-resolution, acoustic profiling system ?Sono-prob?(SP-3W; 3-8kH) and a sidescan sonar (DF1000). Survey lines were designed at 250 m interval to capture the details of fault geometry. The Tepetarla segment on land is traceable for 19km almost straightly and continuously trending east to west with an average displacement of 2.8+-0.2 (one sigma) m. East of the segment continues in to the Sapanca Lake for about10km and makes a releasing double bends as the jog structure between Tepetarla and Arifiye segments. The double bends is 8 km-long and 2 km-wide consists of en-echelon faults with normal component of slip. East on the lake, the jog appeared on land for 2 km-long, as a 500 m-wide graben. Although South on the Arifiye segment there are several secondary faults making a hose tail structure, we couldn?t find any recent fault south of the tepetarla segment in the Sapanca Lake. West of the tepetarla segment continues into the Izmit Bay for 6 km making a releasing pull-apart structure between Golcuk and Tepetarla segments. The basin is 8 km-long, 3 km-wide and about 15 square km, surrounded by faults that have normal component. Subsidence of the large area of south coast of the Izmit Bay during the earthquake suggests that this pull-apart structure stretches at least several km deep. Those differentiations of geometry and size of jogs might strongly influence the rupture process of the 1999 Izmit earthquake.

  13. Structure of the Kasbah fold zone (Agadir bay, Morocco). Implications on the chronology of the recent tectonics of the western High Atlas and on the seismic hazard of the Agadir area

    International Nuclear Information System (INIS)

    Detailed re-interpretation of the north-eastern segment of a profile realized across the Agadir bay along a NE-SW trend and crosscutting the main structures, together with analysis of available isochron maps, allowed us to retrace the geological history of the offshore western High Atlas. Two tectonostratigraphic sequences were distinguished: Unit II, which displays a simple structure, laying un conformably on Unit I, with a more complex structure dominated by a reverse fault (F1) striking E-W with a dip to the north. Correlation to boreholes Souss-1 and AGM-1 allowed us to assign Unit I to the Triassic Palaeogene and Unit II to the Miocene Present. The NE fault block shows a ramp-flat fault plane (F2) with an overlying SW-vergent fold that can be interpreted as a fault-bend fold. Three main stages were distinguished: (1) during the Cretaceous, F1 could have been a syn depositional normal fault with the NE block moving downwards; (2) towards the beginning of the Tertiary, the displacement of plane F2 induced the development of a fault-bend fold and erosion of the forelimb and hinge of the fold; displacement along F2 was transferred to fault F1; (3) afterwards, during the Miocene, reverse motion of F1 deformed and tilted the plane F2 and accentuated the folded structure. This evolution is typical for a frontal basin above a fault-related fold. Evaluation of the thickness and bed depth differences shows that the largest growth rate was recorded in Late Miocene times. Seismic activity recorded in the Agadir bay appears to be clearly related to this fault zone, as inferred from focal mechanisms. Seismic moment evaluation suggests that earthquakes of magnitude Mw=6 are likely to occur, but could not be much larger because of the fault segmentation geometry of the High Atlas Front. (Author) 53 refs.

  14. Impact of environmental inputs on reverse-engineering approach to network structures

    OpenAIRE

    Buchanan-Wollaston Vicky; Sinfield James L; Wu Jianhua; Feng Jianfeng

    2009-01-01

    Abstract Background Uncovering complex network structures from a biological system is one of the main topic in system biology. The network structures can be inferred by the dynamical Bayesian network or Granger causality, but neither techniques have seriously taken into account the impact of environmental inputs. Results With considerations of natural rhythmic dynamics of biological data, we propose a system biology approach to reveal the impact of environmental inputs on network structures. ...

  15. Market power versus capital structure determinants: Do they impact leverage?

    Directory of Open Access Journals (Sweden)

    Agha Jahanzeb

    2015-12-01

    Full Text Available The purpose of this study is to investigate the association between market power and capital structure. This study will further provide a logical explanation towards the factors affecting capital structure. This study analysed 176 non-financial Pakistani companies listed on Karachi Stock Exchange over the period of 2003–2012. Capital structure has been tried to investigate with a different perspective by investigating its association with market power. It has been seen that there is a significant and positive relation between market power and capital structure. Size and liquidity remained significantly negative with capital structure, whereas profitability and dividend payout remained significantly positive with capital structure. To the best of authors’ knowledge, this is the first study that investigates the relationship between market power and capital structure in any developing economy by employing the data of non-financial Pakistani firms.

  16. Yaquina Bay Topobathy DEM

    Science.gov (United States)

    The U.S.EPA contracted with the U.S.ACE to obtain intertidal and subtidal bathymetric soundings of Yaquina Bay between Poole Slough and the South Beach Marina in 2002. These data were compiled with U.S.ACE subtidal soundings from 1999, 1998, 2000 and National Ocean Service soundi...

  17. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors

    Directory of Open Access Journals (Sweden)

    Liang Si

    2015-07-01

    Full Text Available For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI technique mainly consists of five functional modules, which are the signal data preprocessing (SDP, the forward model generator (FMG, the impact positioning calculator (IPC, the inverse model operator (IMO and structural state estimator (SSE. With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with “orange peel” surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments.

  18. Some challenges of an "upside down" nitrogen budget--science and management in Greenwich Bay, RI (USA).

    Science.gov (United States)

    DiMilla, Peter A; Nixon, Scott W; Oczkowski, Autumn J; Altabet, Mark A; McKinney, Richard A

    2011-04-01

    When nutrients impact estuarine water quality, scientists and managers instinctively focus on quantifying and controlling land-based sources. However, in Greenwich Bay, RI, the estuary opens onto a larger and more intensively fertilized coastal water body (Narragansett Bay). Previous inventories of nitrogen (N) inputs to Greenwich Bay found that N inputs from Narragansett Bay exceeded those from the local watershed, suggesting that recent efforts to reduce local watershed N loads may have little effect on estuarine water quality. We used stable isotopes of N to characterize watershed and Narragansett Bay N sources as well as the composition of primary producers and consumers throughout Greenwich Bay. Results were consistent with previous assessments of the importance of N inputs to Greenwich Bay from Narragansett Bay. As multiple N sources contribute to estuarine water quality, effective management requires attention to individual sources commensurate with overall magnitude, regardless of the political complications that may entail. PMID:21353254

  19. Baseline assessment of Guánica Bay, Puerto Rico in support of watershed restoration

    OpenAIRE

    Whitall, David; Bauer, Laurie J.; Sherman, Clark; Edwards, Kimberly; Mason, Andrew; Pait, Tony; Caldow, Chris

    2013-01-01

    Guánica Bay is a major estuary on the southwest coast of Puerto Rico. Significant coral reef ecosystems are present outside the bay. These valuable habitats may be impacted by transport of sediments, nutrients and contaminants from the watershed, through the bay and into the offshore waters. The National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Coastal Ocean Science (NCCOS), in consultation with local and regional experts, conducted an interdisciplinary assessment ...

  20. Expansion of the macroalga Caulerpa racemosa and changes in softbottom macrofaunal assemblages in Moni Bay, Cyprus

    OpenAIRE

    Argyrou, M.; Demetropoulos, A.; Hadjichristophorou, M

    1999-01-01

    The recent expansion of the Red Sea macroalga Caulerpa racemosa and its impact on the diversity and abundance of macrobenthos were examined and compared in the summers of 1992 and 1997, in Moni Bay, Cyprus. The phytobenthic community of the bay in 1992 was dominated by the seagrass Posidonia oceanica while, in 1997, the Lessepsian migrant C. racemosa became the most dominant, forming extensive mars. Changes in the vegetation system in Moni Bay have caused significant compositional changes in ...

  1. Structural capacity assessment of a generic pre-stressed concrete containment structure under aircraft impact

    International Nuclear Information System (INIS)

    The studied containment expressed adequate capacity to resist impact loads in the upper range of the studied diapason. The aircraft impact capacity of the containment for impact in the upper part of the cylindrical shell is about 25‐30% higher than the capacity for impact in the middle part of the cylindrical shell. The obtained fragility curves reefed to MoA can be then used for various additional calculations in the safety assessment of nuclear facilities under aircraft impact

  2. Airborne and impact sound transmission in super-light structures

    DEFF Research Database (Denmark)

    Christensen, Jacob Ellehauge; Hertz, Kristian Dahl; Brunskog, Jonas

    2011-01-01

    Super-light structures are newly invented and based on combining lightweight concrete with normal concrete for lighter structures and better structural performance. The overall principle is based on load carrying arches of a normal concrete stabilised and protected from fire by a light-aggregate ......Super-light structures are newly invented and based on combining lightweight concrete with normal concrete for lighter structures and better structural performance. The overall principle is based on load carrying arches of a normal concrete stabilised and protected from fire by a light...... contribute to lowering the critical frequency of the element. By introducing light-aggregate concrete into the element, the damping will increase as the internal damping for light-aggregate concrete is higher than for normal concrete. It is also a possibility that the connection between the two materials...

  3. Review on Empirical Studies of Local Impact Effects of Hard Missile on Concrete Structures

    OpenAIRE

    Ismail Abdul Rahman; Ahmad Mujahid Ahmad Zaidi; Qadir Bux@ Imran Latif

    2011-01-01

    Concrete is basic construction material used for any kind of structure. However, in most vital and local structures such as nuclear plants, Power plants, Weapon Industries, weapons storage places, water retaining structures like dams, and also local industries, & etc., concrete structures have to be designed as defensive structures to provide protection against any accidents or knowingly generated incidents such as dynamic loading, dynamic local impact damage and global damage generated by ki...

  4. The impact of structure dimensions on initial bacterial adhesion.

    Science.gov (United States)

    Helbig, Ralf; Günther, Denise; Friedrichs, Jens; Rößler, Florian; Lasagni, Andrés; Werner, Carsten

    2016-07-21

    Substrate topography can have profound effects on initial bacterial adhesion during biofilm formation. We applied Staphylococcus epidermidis and Escherichia coli cells onto periodically structured substrates with different structure dimensions, structure types and wetting properties. We found a strong dependence of cell retention on the structure dimensions of the applied substrates. Periodicities in the range of the cell size increased, whereas smaller periodicities decreased cell retention, independent of contact time (minutes to hours) and hydrophobicity. These novel insights on the role of surface topography on bacterial retention might facilitate the development of non-fouling surfaces in the future. PMID:27232637

  5. 湛江湾大型底栖动物的群落结构和多样性特征%Community Structure and Diversity of Macrobenthos in Zhanjiang Bay

    Institute of Scientific and Technical Information of China (English)

    周伟男; 孙省利; 李荣冠; 江锦祥; 张才学

    2013-01-01

    The situations of macrobenthos in Zhanjiang Bay have been investigated in 10 sites during May 2010, analyzing the species composition, biomass, population density and species diversity and classifying on community structure by the method of CLUSTER and MDS. A total of 112 species of 7 phyla were identified, including Annelida, Mollusca and Arthropoda, which were the dominant phyla in Zhanjiang Bay. Biomass ranged from 0.93 to 98.20 g/m2, with the highest average biomass of Mollusca. Population density ranged for 6.11 to 24.80 ind/m2, and population density of Annelida (24.08 ind/m2) was the highest, followed by Sipuncula (22.22 ind/m2). The community species of the macrobenthos in the area is relatively abundant while the diversity is poor. According to the analysis of clustering and multidimensional scaling ordination, macrobenthic animals in Zhanjiang Bay could be divided into 4 communities. Through the abundance/biomass curve analysis, macrobenthic organisms in Zhanjiang Bay was affected so seriously by environmental pollution or disturbance that the community structure was unstable. Compared with the other marine sites,the number of species, biomass and abundance of the Zhanjiang Bay were lower.%  2010年5月,在湛江湾海域设立10个站点对大型底栖生物进行调查,分析湛江湾大型底栖生物的种类组成、生物量、栖息密度和生物多样性特征,并通过聚类(CLUSTER)和MDS排序对大型底栖生物群落进行划分.结果表明,调查海域共有底栖生物共7门112种,环节动物门、软体动物门和节肢动物门为湛江湾大型底栖生物的主要类群.生物量分布范围为0.93~98.20 g·m-2,其中软体动物门的平均生物量最高值.栖息密度分布范围为6.11~24.80 ind·m-2,其中以环节动物门(24.08 ind·m-2)和星虫动物门(22.22 ind·m-2)最高.该海域大型底栖生物群落物种较为丰富,但多样性差.根据Bray-Curtis相似性系数聚类分析和多维尺度排序分析结

  6. Impacts of Hazardous Air Pollutants Emitted from Phosphate Fertilizer Production Plants on their Ambient Concentration Levels in the Tampa Bay Area

    Science.gov (United States)

    The concentrations and distribution of Hazardous Air Pollutants (HAPs) metals emitted from four phosphate fertilizer plants in Central Florida, as well as their environmental and health impacts, were assessed. The dominant HAP metals emitted from the stacks of these plants were M...

  7. Droplet impact on superheated micro-structured surfaces

    NARCIS (Netherlands)

    Tran, A.T.; Staat, H.J.J.; Susarrey-Arce, A.; Foertsch, T.C.; Houselt, van A.; Gardeniers, J.G.E.; Prosperetti, A.; Lohse, D.; Sun, C.

    2013-01-01

    When a droplet impacts upon a surface heated above the liquid's boiling point, the droplet either comes into contact with the surface and boils immediately (contact boiling), or is supported by a developing vapor layer and bounces back (film boiling, or Leidenfrost state). We study the transition be

  8. Impact of Seed Structure Modification on the Rate

    Czech Academy of Sciences Publication Activity Database

    Rochová, Kristina; Sovová, Helena; Sobolík, Václav; Allaf, K.

    2008-01-01

    Roč. 44, č. 2 (2008), s. 211-218. ISSN 0896-8446 R&D Projects: GA AV ČR(CZ) GA104/06/1174 Institutional research plan: CEZ:AV0Z40720504 Keywords : dic process * supercritical extraction * porosity Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.428, year: 2008

  9. ANALYSIS ON IMPACT RESPONSES OF UNRESTRAINED PLANAR FRAME STRUCTURE(Ⅰ)-FORMULA DERIVATION

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; ZHENG Hai-tao; XUE Song-tao; TANG He-sheng

    2005-01-01

    The generalized Fourier-series method was used to derive the impact responses formula of an unrestrained planar frame structure when subjected to an impact of a moving rigid-body. By using these formula, the analytic solutions of dynamic responses of the contact-impact system can be obtained. During the derivation, the momentum sum of elastic responses of the contact-impact system is demonstrated to be zero. From the derivation, it is seen that the modal method can also be used to solve this kind of impact problem.

  10. Plastic buckling·behaviour of a thin-plate structure by lateral impact loading

    International Nuclear Information System (INIS)

    The objective of this research is to evaluate the plastic buckling behaviour of the thin plate grid structure. To perform this objective, two kinds of approaches are taken in this work. First, in order to obtain the test data on the dynamic failure behaviour of the grid, an impact test is performed with a 8 x 8 cell size partial grid specimen, which is made of Zircaloy-4 thin plate. Second, a finite element (FE) analysis method for predicting the buckling behaviour on the spacer grid structure is established by a commercial FE code ABAQUS/explicit. In this FE analysis method, appropriate boundary conditions and impact loading conditions are applied to simulate the actual test conditions. The dynamic impact analysis is performed to evaluate the plastic buckling behaviour of a grid structure under the lateral impact load. The FE model is produced using pre-processor I-DEAS, and solved using nonlinear commercial solver ABAQUS/explicit. In this work, a FE model is created using the multi-point constraint (MPC) conditions. Applied boundary conditions for dynamic impact analysis were almost the same as the actual boundary conditions for the impact test. This FE model will be compared with test results. The plastic buckling behaviour of a thin-plate structure is dependent on the external impact velocity of the hammer. In addition, the dynamic buckling behaviour of a thin-plate structure is gradually continued due to the internal impact energy absorption. (author)

  11. Optical and structural characterization of the pure and doped BaY2F8 with rare earths for application in radiation detectors and scintillators

    International Nuclear Information System (INIS)

    In this work Barium Yttrium Fluoride (BaY2F8 -BaYF) doped with different concentrations of ions Tb3+, Er3+, Tm3+ e Nd3+ were characterized, aiming the application in radiation detection devices that use the scintillating properties. Two types of samples were produced in the CLA-IPEN-SP, polycrystalline samples, obtained via solid state reaction of BaF2 and YF3 under HF atmosphere, and single crystals, obtained via the zone melting method also in a HF atmosphere. The samples were characterized using the following experimental techniques: X-ray powder diffraction, Radioluminescence (RL), Optical Absorption and Dispersive X-ray Absorption Spectroscopy (DXAS). The X-ray diffraction pattern showed the presence of the phase BaY2F8 and a small amount of the phase Ba4Y3F17 in the polycrystalline pure and Tb3+doped samples. The other samples showed only the desired BaY2F8 phase. The radioluminescence measurements of the doped BaYF, when irradiated with X-rays, showed emission peaks in energies that are characteristics of the 4f-4f transitions of rare earths. The RL of the samples with 2 mol por cent and 3 mold of Tb3+showed quite intense peaks with a maximum emission peak at 545 nm. The Tm3+doped BYF showed that the scintillation efficiency is not directly proportional to the doping level, and the highest RL emission were obtained for the polycrystalline samples doped with 1 mol por cent, showing a maximum peak intensity at 456 nm (the blue region of the visible spectrum). All samples showed a phosphorescent decay time of the order of seconds. Single crystals of BaYF doped with 2 mol por cent of Er3+, in addition to one of the highest phosphorescence time, presents a quite strong Rl in the green region of the spectra. The radiation damage was evaluated by the optical absorption techniques and the results showed that the formation of the absorption bands can be connected to colors centers generated by radiation in the matrix. Measurements of DXAS, done at the LNLS DXAS

  12. Improvement of the impact analysis model of the grid structure considering multi constraints condition

    International Nuclear Information System (INIS)

    The dynamic impact analysis is performed for predicting the buckling behavior of a grid structure under the lateral impact load by finite element method. The grid structure is composed of several thin plates which were inserted each other and then each contact places were welded by laser welding. The finite element model is produced using preprocessor I-DEAS, and solved using nonlinear commercial solver ABAQUS/explicit. In this work, two models are proposed for FE analysis. One is the simplified model and the other is multi constrained one. Applied boundary conditions for dynamic impact analysis were nearly the same with actual boundary conditions for impact test. The dynamic impact parameters of a grid structure such as critical impact acceleration, impact force and buckling mode and so on, are over-estimated with test results. Based on these results, the FE analysis model of the grid structure is need to modify the stiffness of a grid cell structure. According to these results, the FE model is modified for estimating the buckling behavior of grid structure. This modified FE model will be compared with test and analysis results using the simplified model

  13. Hydrogeological impacts of road salt from Canada's busiest highway on a Lake Ontario watershed (Frenchman's Bay) and lagoon, City of Pickering.

    Science.gov (United States)

    Meriano, Mandana; Eyles, Nick; Howard, Ken W F

    2009-06-26

    The quantity of deicing salt applied to paved surfaces in urban watersheds in cold regions has had a significant and cumulative effect on groundwater quality. Whereas road deicing salt is known in general to impact groundwater and surface water quality, quantitative information on the impact of large transport routes is lacking. In this study, we provide a chloride mass balance for an urban stream crossed by a large transport route in south-central Ontario, Canada and quantify likely long-term impacts of salt loading on surface and groundwater resources. The chloride mass balance, supported by hydrochemical analysis, reveals that approximately 50% of the total road salt applied to Pine Creek (1700 tonnes per winter) is removed annually via overland flow with the remainder accumulating in the shallow subsurface resulting in severe degradation of groundwater quality. Moreover, results show that road salt migration is the primary reason for enhanced mineral weathering in the shallow aquifer. During the 2004-05 salting season, runoff and baseflow transport of road salts were responsible for chloride concentrations in the stream of up to 2000 mg L(-1), and delivered approximately 850 tonnes of chloride (about 1400 tonnes of salt) to a shallow (watershed is estimated at 3700 tonnes each year with up to 48% of the total load delivered by baseflow, the remainder from surface water runoff. Present day groundwater chloride concentrations are estimated to be about 80% of long-term concentrations when the system reaches steady state. PMID:19464750

  14. A reevaluation of the late quaternary sedimentation in todos os Santos Bay (BA, Brazil

    Directory of Open Access Journals (Sweden)

    GUILHERME C. LESSA

    2000-12-01

    Full Text Available Todos os Santos Bay is a large ( 1000 km², structurally controlled tidal bay in northeast Brazil. Three main drainage basins debouch into the bay, providing a mean freshwater discharge of 200 m³/s (prior to 1985, or less than 1% of the spring tidal discharge through the bay mouth. Based on the result of several sedimentological studies performed in the 1970's, five surface sedimentary facies were identified inside the bay, namely i transgressive siliciclastic marine sand facies; ii transgressive bay sand-mud facies; iii a transgressive carbonate marine sand facies; iv regressive bay-mud facies, and v regressive fluvial sand facies. The spatial distribution of these facies would follow, somewhat closely, the hydrodynamic-energy distribution inside the bay. Seismic profiles along the bay bottom indicate the existence of several paleochannels, 5-10 m deep, blanketed at least by three different sedimentary units. The topmost sedimentary unit, 5-20 m thick, appears to be associated with the regressive bay-mud facies, and assuming that it was laid down within the last 5000 years, sedimentation rates for the central and northeastern part of the bay would average at 2,4 mm/y.

  15. Impact of oil on bacterial community structure in bioturbated sediments

    OpenAIRE

    Stauffert, Magali; Cravo-Laureau, Cristiana; Jezequel, Ronan; Barantal, Sandra; Cuny, Philippe; Gilbert, Franck; Cagnon, Christine; Militon, Cécile; Amouroux, David; Mahdaoui, Fatima; Bouyssiere, Brice; Stora, Georges; Merlin, François-Xavier; Duran, Robert

    2013-01-01

    Oil spills threaten coastlines where biological processes supply essential ecosystem services. Therefore, it is crucial to understand how oil influences the microbial communities in sediments that play key roles in ecosystem functioning. Ecosystems such as sediments are characterized by intensive bioturbation due to burrowing macrofauna that may modify the microbial metabolisms. It is thus essential to consider the bioturbation when determining the impact of oil on microbial communities. In t...

  16. The Cantarell Breccia System, Southern Gulf Of Mexico: Structural Evolution And Support For An Origin Relarted To The Chixculub Meteorite Impact

    Science.gov (United States)

    Ricoy, V.

    2003-04-01

    The Upper Cretaceous within the Campeche Basin, southern Gulf of Mexico hosts a world class petroleum system. Cantarell is the most important reservoir that consists of a complex brecciated carbonate reservoir deposited at or around the Cretaceous-Tertiary boundary. Previous sedimentological studies suggests that the Upper Cretaceous Carbonate breccias found in the Cantarell oilfield system and through the Bay of Campeche, were the result of a catastrophic shelf collapse event triggered by the Chixculub meteorite impact. This work presents new evidence from structural and stratigraphic interpretation of 3D seismic and 2D lines which gives light to features that support the platform collapse model. The reservoir consists of thick (up to 300 m), heterogeneous, monomyctic and polymictic breccias developed at the K-T boundary, and widely distributed throughout the Campeche Basin. The timing, internal architecture, widespread deposition and distance to the platform margin source (over 30 kms) of the breccia unit, combined with a contorted irregular seismic reflector near the base of the Cretaceous carbonate platform, suggests that the geological processes accountable for the emplacement of the breccias relates to the massive catastrophic collapse of the Cretaceous platform as a result of the Chixculub meteorite impact. Structural interpretation of the 3D seismic data, together with well stratigraphic markers unraveled a complex Oligocene-Miocene structural deformation history of the Cantarell field, which resulted in several discrete reservoir blocks partitioned by a complex array of thrusts, normal and reverse faults. It is proposed that the structural deformation of the area controlled to a large extent the distribution of the reservoir properties found in the Cantarell area. This idea is tested using the structural model matched against the well log porosity data.

  17. Impact of Temperature on Cooling Structural Variation of Forging Dies

    Science.gov (United States)

    Piesova, Marianna; Czan, Andrej

    2014-12-01

    The article is focused on the issue of die forging in the automotive industry. The cooling effect of temperature on the structure of forged die are under review. In the article, there is elaborated the analysis of theoretical knowledge in the field, focusing on die forging and experimentally proven effect of the cooling rate on the final structure of forged dies made of hypoeutectic carbon steel C56E2.

  18. Bayes linear covariance matrix adjustment

    CERN Document Server

    Wilkinson, Darren J

    1995-01-01

    In this thesis, a Bayes linear methodology for the adjustment of covariance matrices is presented and discussed. A geometric framework for quantifying uncertainties about covariance matrices is set up, and an inner-product for spaces of random matrices is motivated and constructed. The inner-product on this space captures aspects of our beliefs about the relationship between covariance matrices of interest to us, providing a structure rich enough for us to adjust beliefs about unknown matrices in the light of data such as sample covariance matrices, exploiting second-order exchangeability and related specifications to obtain representations allowing analysis. Adjustment is associated with orthogonal projection, and illustrated with examples of adjustments for some common problems. The problem of adjusting the covariance matrices underlying exchangeable random vectors is tackled and discussed. Learning about the covariance matrices associated with multivariate time series dynamic linear models is shown to be a...

  19. Thermal Metamorphic Signature in Melt-Bearing Polymict Breccias from the Steen River Impact Structure, Canada

    Science.gov (United States)

    Walton, E. L.; Dence, M. R.; Herd, C. D. K.

    2015-07-01

    Melt-bearing polymict breccias within drillcore from the Steen River impact structure are described which contain a matrix of clinopyroxene + feldspar + titanite + garnet + oxides formed by recyrstallization of a superheated clastic dust.

  20. Reinforced concrete structures under impact and impulsive loading: recent development, problems and trends

    International Nuclear Information System (INIS)

    Nuclear plant facilities and other reinforced concrete structures have to be regarded as to their safety in design and construction with respect to impact and impulsive loading in order to avoid serious damage to mankind and environment. The paper gives a survey on theoretical and experimental developments currently in progress, in particular regarding airplane crash. Some new results arising out of several research programs relevant to particular problems of impact loading have been reviewed and are presented. Experimental investigation for determination of material properties of plain concrete, reinforcing steel as well as steel-concrete bond under high strain-rates are treated in this paper including theoretical approaches for the respective material laws. An outline of soft missile impact tests performed on structural members, e.g. beams and plates, to determine the load deformation or fracture behaviour is given. Furthermore, numerical models and calculations to analyse structural components and structures under impact loading were discussed. (Author)

  1. Intracrater Evaporite Deposits of the Lake St. Martin Impact Structure: Implications for Mars

    Science.gov (United States)

    Stromberg, J.; Berard, G.; Mann, P.; Cloutis, E.

    2011-03-01

    The gypsum-rich intracrater evaporate deposits of the Lake St. Martin impact structure and its spectrally detectable endolithic microbial communities make it a relevant analogue for similar deposits on Mars.

  2. Vulnerability Assessment for a Complex Structure Using Vibration Response Induced by Impact Load

    International Nuclear Information System (INIS)

    This work presents a vulnerability assessment procedure for a complex structure using vibration characteristics. The structural behavior of a three-dimensional framed structure subjected to impact forces was predicted using the spectral element method. The Timoshenko beam function was applied to simulate the impact wave propagations induced by a high-velocity projectile at relatively high frequencies. The interactions at the joints were analyzed for both flexural and longitudinal wave propagations. Simulations of the impact energy transfer through the entire structure were performed using the transient displacement and acceleration responses obtained from the frequency analysis. The kill probabilities of the crucial components for an operating system were calculated as a function of the predicted acceleration amplitudes according to the acceptable vibration levels. Following the proposed vulnerability assessment procedure, the vulnerable positions of a three-dimensional combat vehicle with high possibilities of damage generation of components by impact loading were identified from the estimated vibration responses

  3. The Transfinite High-rise Structure Design of Number 43 Floor in Zhongrong Xinghai Bay%中融星海湾43号楼超限高层结构设计

    Institute of Scientific and Technical Information of China (English)

    邹朝阳

    2013-01-01

    The number 43 floor project in Zhongrong Xinghai Bay is shear wal structure, the structure is 132.40 m high, whi-ch is a transfinite high-rise building. This article introduces the general situation of the project, seismic design objectives, etc., analyzes the structure under the different seismic force, and takes strengthening measures in the weak parts of structure to ensure the seismic safety of the structure.%  中融星海湾43号楼工程为剪力墙结构,结构高132.40 m,为超限高层建筑。本文介绍了该工程的概况、抗震设计目标等,对不同地震力作用下的结构进行了分析,对结构中存在的薄弱部位应采取加强措施,确保结构的抗震安全性。

  4. Understanding the Impact of Trauma Exposure on Posttraumatic Stress Symptomatology: A Structural Equation Modeling Approach

    Science.gov (United States)

    Chen, Wei; Wang, Long; Zhang, Xing-Li; Shi, Jian-Nong

    2012-01-01

    The objective of this study was to investigate the impact of trauma exposure on the posttraumatic stress symptomatology (PTSS) of children who resided near the epicenter of the 2008 Wenchuan earthquake. The mechanisms of this impact were explored via structural equation models with self-esteem and coping strategies included as mediators. The…

  5. Chemistry of Tertiary sediments in the surroundings of the Ries impact structure and moldavite formation revisited

    Czech Academy of Sciences Publication Activity Database

    Žák, Karel; Skála, Roman; Řanda, Zdeněk; Mizera, Jiří; Heissig, K.; Ackerman, Lukáš; Ďurišová, Jana; Jonášová, Šárka; Kameník, Jan; Magna, T.

    2016-01-01

    Roč. 179, 15 April (2016), s. 287-311. ISSN 0016-7037 R&D Projects: GA ČR GA13-22351S; GA MŠk(CZ) LM2011019 Institutional support: RVO:67985831 ; RVO:61389005 Keywords : sediments * tertiary * tektites * moldavites * Ries impact structure Subject RIV: DB - Geology ; Mineralogy Impact factor: 4.331, year: 2014

  6. Impact of Point and Non-point Source Pollution on Coral Reef Ecosystems In Mamala Bay, Oahu, Hawaii based on Water Quality Measurements and Benthic Surveys in 1993-1994 (NODC Accession 0001172)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The effects of both point and non-point sources of pollution on coral reef ecosystems in Mamala Bay were studied at three levels of biological organization; the...

  7. Modeling Competitive Marketing Strategies: The Impact of Marketing-Mix Relationships and Industry Structure

    OpenAIRE

    Gregory S. Carpenter

    1987-01-01

    This paper empirically analyzes the formulation of competitive marketing strategies consisting of product quality levels, promotional expenditures and prices. Using a simultaneous-equation model, we examine the use of prices and promotional spending as signals or indications of product quality, the impact of promotional spending on prices, and the impact of industry structure on the formulation of the complete marketing mix. The structural equations are developed using a theoretical model of ...

  8. Structural Intervention Time Series Analysis of Crime Rates: The Impact of Sentence Reform in Virginia

    OpenAIRE

    S. Vujic; Commandeur, J J F; Koopman, S.J.

    2012-01-01

    We adopt a structural time series analysis to investigate the impact of parole abolition and sentence reform in Virginia on reported crime rates. The Commonwealth of Virginia abolished parole and reformed sentencing for all felony offences committed on or after January 1, 1995. To examine the impact of Virginia's change in legislation on reported crime rates from 1995 onwards, we perform an intervention time series analysis based on structural time series models. We empirically find that the ...

  9. IMPACT OF AN AMENDMENT FOR SOIL STRUCTURE IMPROVING ON SOIL AT SPRINKLING

    OpenAIRE

    Nozadze L. R.; Slabunov V. V.

    2015-01-01

    The article presents the research results of the impact of amendment improving soil structure on soil upon sprinkler irrigation of agricultural lands. It is proposed to use artificial aggregation of soil for water erosion control via composition of structure-forming materials. The developed composition includes slagheap rock, bentonitic clay, claydite screenings, and shell limestone. Adjusted analytical relations of the impact of the amendment on runoff coefficient depending on the intensity ...

  10. The impact of Broadband quality standards on Internet services market structure in Colombia

    OpenAIRE

    Hidalgo, Julian; Oviedo, Juan D.

    2014-01-01

    This paper develops a structural model which allows estimating the impact of regulatory decisions looking for the setting of download-speed standards on market structure and performance. We characterize a setting under which quality standards improve both service quality and availability. As to quality, we evaluate the impact of quality standards on the performance of local demand from a detailed database of broadband internet subscribers, discriminated by the main attributes of an internet s...

  11. Factors that impact a virtual commander in a concurrent command structure.

    OpenAIRE

    Waugh, Alexander J.

    1997-01-01

    This thesis analyzes factors that impact a Virtual Commander. In- depth interviews with personnel at the Naval Postgraduate School and the George C. Marshall Center for European Studies informed the development of a case study documenting the implementation and maintenance of a virtual command structure. Qualitative and archival data are analyzed to inform the professional officer corps about factors that impact a virtual command structure. Based in a systems approach, seven factors frame the...

  12. The Impact of Personal and Corporate Taxation on Capital Structure Choices

    OpenAIRE

    Voeller, Dennis; Overesch, Michael

    2008-01-01

    This paper empirically analyses whether both personal and corporate taxation have an impact on companies' capital structure decisions. We investigate the effect of the difference in taxation of debt and equity financing on capital structures. Our empirical results, based on a comprehensive panel of European firm-level data, suggest that a higher tax benefit of debt has the expected significant positive impact on a company's financial leverage. Particularly, we find evidence that the capital s...

  13. Impact of Acoustic Standing Waves on Structural Responses

    Science.gov (United States)

    Kolaini, Ali R.

    2014-01-01

    For several decades large reverberant chambers and most recently direct field acoustic testing have been used in the aerospace industry to test larger structures with low surface densities such as solar arrays and reflectors to qualify them and to detect faults in the design and fabrication. It has been reported that in reverberant chamber and direct acoustic testing, standing acoustic modes may strongly couple with the fundamental structural modes of the test hardware (Reference 1). In this paper results from a recent reverberant chamber acoustic test of a composite reflector are discussed. These results provide further convincing evidence of the acoustic standing wave and structural modes coupling phenomenon. The purpose of this paper is to alert test organizations to this phenomenon so that they can account for the potential increase in structural responses and ensure that flight hardware undergoes safe testing. An understanding of the coupling phenomenon may also help minimize the over and/or under testing that could pose un-anticipated structural and flight qualification issues.

  14. The impact of structured teaching methods on the quality of education

    OpenAIRE

    Leme, Maria Carolina da Silva; Louzano, Paula; Ponczek, Vladimir Pinheiro; Souza, André Portela

    2012-01-01

    This paper estimates the impact of the use of structured methods on the quality of education of the students in primary public school in Brazil. Structure methods encompass a range of pedagogical and managerial instruments applied to the education system. In recent years, several municipalities in the State of São Paulo have contracted out private educational providers to implement these structured methods in their schooling system. Their pedagogical proposal involves structuring curriculum c...

  15. Quantification of the impact of PSI:Biology according to the annotations of the determined structures

    OpenAIRE

    DePietro, Paul J; Julfayev, Elchin S.; McLaughlin, William A.

    2013-01-01

    Background Protein Structure Initiative:Biology (PSI:Biology) is the third phase of PSI where protein structures are determined in high-throughput to characterize their biological functions. The transition to the third phase entailed the formation of PSI:Biology Partnerships which are composed of structural genomics centers and biomedical science laboratories. We present a method to examine the impact of protein structures determined under the auspices of PSI:Biology by measuring their rates ...

  16. A compilation of structural property data for computer impact calculation (5/5)

    International Nuclear Information System (INIS)

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 5 involve structural property data of wood. (author)

  17. A compilation of structural property data for computer impact calculation (4/5)

    International Nuclear Information System (INIS)

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 4 involve structural property data of lead. (author)

  18. Support for EU fundraising in the field of Environment & Energy - BayFOR

    Science.gov (United States)

    Ammerl, Thomas; Baumann, Cornelia; Reiter, Andrea; Blume, Andreas; Just, Jana; Franke, Jan

    2013-04-01

    The Bavarian Research Alliance (BayFOR, http://www.bayfor.org) is a private company for the support of Bavaria (Free State in the South East of Germany) as a centre for science and innovation within the European Research Area. It was set up on the initiative of the Bavarian universities to strengthen their networking at regional, national and international level while helping them to prepare to meet the requirements for European research funding. The focus is directed at the current EU Framework Programme (FP7) and the forthcoming Framework Programme for Research and Innovation "Horizon 2020", but also comprises the wide range of European programmes (e.g. FP7, LIFE+, Interreg, COST, EUREKA, ERA-Nets, IEE (CIP), LLP, Calls for tender). BayFOR is also a partner institution in the Bavarian "Haus der Forschung" (www.hausderforschung.bayern.de/en). BayFORs overall aim is to strengthen and permanently anchor the science and innovation location of Bavaria in the European Research Area through: a) Initiation of national and in particular European innovation and science partnerships from academia and business b) Improvement of innovation potential of Bavarian universities and SME c) Support in acquisition, management and dissemination of results of European and international projects in the field of research and technological development The service portfolio of the EU Funding Advisory Service reaches from the first project idea to project implementation. The minimum condition for BayFOR support is at least one partner from Bavaria (Germany) must be part of the applying consortium: a) Recommendation of funding programmes/instruments (incl. integration of relevant EU policies & directives) b) Partner search c) Project development and proposal elaboration (Online platform, Creation of consortium, Attendance at meetings, Preparation of documents, Proposal structure elaboration, Provision of templates, Editorial support: Gantt, PERT, Impact, EU added value) d) Support in the

  19. Modeling of fracture of protective concrete structures under impact loads

    Science.gov (United States)

    Radchenko, P. A.; Batuev, S. P.; Radchenko, A. V.; Plevkov, V. S.

    2015-10-01

    This paper presents results of numerical simulation of interaction between a Boeing 747-400 aircraft and the protective shell of a nuclear power plant. The shell is presented as a complex multilayered cellular structure consisting of layers of concrete and fiber concrete bonded with steel trusses. Numerical simulation was performed three-dimensionally using the original algorithm and software taking into account algorithms for building grids of complex geometric objects and parallel computations. Dynamics of the stress-strain state and fracture of the structure were studied. Destruction is described using a two-stage model that allows taking into account anisotropy of elastic and strength properties of concrete and fiber concrete. It is shown that wave processes initiate destruction of the cellular shell structure; cells start to destruct in an unloading wave originating after the compression wave arrival at free cell surfaces.

  20. Impact of structural reforms on planning systems and policies

    DEFF Research Database (Denmark)

    Galland, Daniel; Enemark, Stig

    2013-01-01

    spatial development processes. The reasoning behind this argument stems from the case of Denmark, where a structural reform that changed the country’s geographies of inter-governmental arrangements significantly transformed the configuration and functioning of the national spatial planning system. Once...... designed to pursue ‘equal development’ as a result of a structural reform of a different nature implemented during the 1970s, Danish planning as a whole and national and regional planning policies, in particular, currently seem to have become less ‘spatial’ in the sense that the latter only tend to exhibit...... limited strategic reasoning and geographical thinking in addressing the potential physical structure of and functional relationships within the national territory. At the same time, the planning system seems to display narrower measures of spatial coherence in terms of horizontal and vertical coordination...

  1. Modeling of fracture of protective concrete structures under impact loads

    International Nuclear Information System (INIS)

    This paper presents results of numerical simulation of interaction between a Boeing 747-400 aircraft and the protective shell of a nuclear power plant. The shell is presented as a complex multilayered cellular structure consisting of layers of concrete and fiber concrete bonded with steel trusses. Numerical simulation was performed three-dimensionally using the original algorithm and software taking into account algorithms for building grids of complex geometric objects and parallel computations. Dynamics of the stress-strain state and fracture of the structure were studied. Destruction is described using a two-stage model that allows taking into account anisotropy of elastic and strength properties of concrete and fiber concrete. It is shown that wave processes initiate destruction of the cellular shell structure; cells start to destruct in an unloading wave originating after the compression wave arrival at free cell surfaces

  2. Modeling of fracture of protective concrete structures under impact loads

    Energy Technology Data Exchange (ETDEWEB)

    Radchenko, P. A., E-mail: radchenko@live.ru; Batuev, S. P.; Radchenko, A. V.; Plevkov, V. S. [Tomsk State University of Architecture and Building, Tomsk, 634003 (Russian Federation)

    2015-10-27

    This paper presents results of numerical simulation of interaction between a Boeing 747-400 aircraft and the protective shell of a nuclear power plant. The shell is presented as a complex multilayered cellular structure consisting of layers of concrete and fiber concrete bonded with steel trusses. Numerical simulation was performed three-dimensionally using the original algorithm and software taking into account algorithms for building grids of complex geometric objects and parallel computations. Dynamics of the stress-strain state and fracture of the structure were studied. Destruction is described using a two-stage model that allows taking into account anisotropy of elastic and strength properties of concrete and fiber concrete. It is shown that wave processes initiate destruction of the cellular shell structure; cells start to destruct in an unloading wave originating after the compression wave arrival at free cell surfaces.

  3. Impact of oils and coatings on adhesion of structural adhesives

    OpenAIRE

    Hagström, Marcus

    2015-01-01

    This is a master thesis project conducted for Scania CV AB in collaboration with Swerea Kimab. The purpose is to examine how oils and coatings on the surface affect the adhesion of adhesives. Earlier work done by Scania indicate that the amount of oil applied may have an impact on the adhesion. Substrates tested are hot dipped galvanised steel, electro galvanised. AlSi and ZnMg. Oils used are Anticorit RP 3802 that is an anti-corrosive oil and Renoform 3802 that is a drawing oil. The two adhes...

  4. National customer satisfaction indices: The impact of market structure

    DEFF Research Database (Denmark)

    Eskildsen, Jacob Kjær; Kristensen, Kai

    a total of 14540 customers have evaluated their preferred supplier with respect to banking, property insurance, supermarkets and mobile telecom. The analysis shows that market structure has a profound effect on customer satisfaction measurements and that this effect differs from industry to industry......The popularity of customer satisfaction measurements has grown considerably over the last few years but we know very little about how the structure of the individual markets with respect to the transparency of products and services as well as consumer preferences affects customer satisfaction. Here....... The paper concludes with an evaluation of the implications of the findings in relation to the use of results from customer satisfaction studies....

  5. The Impact of Capital Structure on Stock Returns: International Evidence

    Directory of Open Access Journals (Sweden)

    Reza TAHMOORESPOUR

    2015-03-01

    Full Text Available This study examines the relationship between capital structure and stock returns of firms in the following eight countries in the Asia Pacific regionfor a period of 22 years from 1990 to 2012. The methodology is Panel Regression. The results indicate that the effect of capital structure depends on the nature of industry as well as market. In Australia, China, and Korea, return of companies in the Basic Material industry have negative relationship with debt to common equity. Long term debt to common equity positively affects the return of firms in Australia and Korea in the Basic Material industry.

  6. A Meramod® model approach for the Environmental Impact Assessment (EIA of the off–shore aquaculture improvement in the Alghero Bay (North western Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    M. Saroglia

    2010-04-01

    Full Text Available Marine fish farming generates particulate wastes which are dispersed in the sea environment. To deal with this problem, particulate waste dispersion models have been developed to predict the effects of fish cage culture. In this study, we evaluated the seabed deposition of a fish farming facility located in the central western Mediterranean by using the Meramod® model. The objectives where first to assess the actual scenario, and second to forecast the possible impact due to the forthcoming enlargement of the farming area with the addition of new fish cages. By computing the hydrodynamic measurements and the daily amount of feed recorded between July and December 2006, the impact seabed surfaces forecasted by the model increased from 5.6ha in the actual scenario, up to 7.3ha in the future. The model estimated a maximum level of total solid flux deposition of 3,800g/m2bed/year and a maximum level of total carbon flux deposition of 1,350g/m2bed/year for both scenarios. Furthermore, the model predicted that the installation of 4 new fish cages (with an hypothetical mean daily amount of feed of 50kg/cage will produce a total solid and carbon flux deposition levels ranging 0-400 and 0-150g/m2bed/year respectively, under the new fish cages location.

  7. Upper Newport Bay Restoration Plan

    OpenAIRE

    Halsch, Chris; Wessling, Jaenna; Lister, Anne; Beck, Emily; Zembel, Richard; Yurko, Matt; Kimball, Sarah

    2016-01-01

    The overall goal of this restoration plan is to assist stakeholders in matching restoration projects with funding opportunities in order to increase the overall health of the Upper Newport Bay. Specifically, this document aims to assess current health and quality of native habitats in and around the bay, and to identify areas needing restoration. We have compiled data on the ecology of the bay, including extent of non-native plant invasion, restoration history and progress, site accessibility...

  8. The Impact of Capital Structure and Ownership Structure on Firm Performance:A Case Study of Iranian Companies

    Directory of Open Access Journals (Sweden)

    Hossein Nabiei Boroujeni

    2013-12-01

    Full Text Available This study examines the effect of capital structure and ownership structure on Firm’s performance using sample of 123 companies listed on Tehran Stock Exchange (TSE during eight-year period, 2001-2008. We adopt rate of return on assets as a measure of firm’s performance. The research results show that capital structure and ownership structure have a positive impact on the performance of companies listed on TSE. This study indicates consistency with prior empirical researches and also all research subsidiary hypotheses are consistent with the theoretical assumptions and all of them have been approved.

  9. Grid faults' impact on wind turbine structural loads

    DEFF Research Database (Denmark)

    Hansen, Anca D.; Cutululis, A. Nicolaos; Sørensen, Poul; Iov, Florin; Larsen, Torben J.

    2007-01-01

    strategy, where the focus is on how to access a proper combination of two complimentary simulations tools, such as the advanced aeroelastic computer code HAWC2 and the detailed power system simulation tool DIgSILENT, in order to provide a whole overview of both the structural and the electrical behaviour...

  10. 75 FR 11837 - Chesapeake Bay Watershed Initiative

    Science.gov (United States)

    2010-03-12

    ... Commodity Credit Corporation Chesapeake Bay Watershed Initiative AGENCY: Commodity Credit Corporation and... program funds for the Chesapeake Bay Watershed Initiative. SUMMARY: The Commodity Credit Corporation (CCC... Watershed Initiative for agricultural producers in the Chesapeake Bay watershed in the States of...

  11. The impact of acquiescence on the evaluation of personality structure.

    Science.gov (United States)

    Rammstedt, Beatrice; Farmer, Richard F

    2013-12-01

    Acquiescence, or the tendency to respond to descriptions of conceptually distinct personality attributes with agreement/affirmation (acceptance acquiescence) or disagreement/opposition (counter-acquiescence), has been widely recognized as a source of bias that can substantially alter interitem correlations within scales. Acquiescence is also known to operate differently among some groups of persons; it is, for example, more pronounced among individuals with less formal education. Consequently, the biasing effects of acquiescence are of particular concern when the dimensionality underlying the item set of a measure is examined with representative samples comprised of persons with varying levels of educational attainment and evaluated with correlation-based statistical methods such as factor analysis. In the present study, we extended our earlier research by investigating the biasing effect of acquiescence on personality factor structures derived from the full-scale version of the Big Five Inventory (BFI) when administered to a large sample (N = 1,427) selected to be representative of Germany's adult population. Consistent with previous findings based on a short-scale version of the BFI, factor analyses of the unadjusted BFI item set failed to replicate the expected Big Five-factor structure in the low/medium and high educational groups, with distortions in factor structure more pronounced in the former group. Once acquiescence was controlled in the item responses for both groups, however, the obtained factor structures were consistent with the Big Five framework. The implications of acquiescence on the evaluation of the factor structure of personality inventories and for the validity of personality assessments are discussed. PMID:23815112

  12. BCDC Bay Trail Alignment 2009

    Data.gov (United States)

    California Department of Resources — The Bay Trail provides easily accessible recreational opportunities for outdoor enthusiasts, including hikers, joggers, bicyclists and skaters. It also offers a...

  13. CHARACTERISTICS OF STRUCTURE OF IMPACT COPOLYMERS OF POLYPROPYLENE WITH LOW ETHYLENE CONTENTS

    Institute of Scientific and Technical Information of China (English)

    MA Dezhu; LI Xiqiang; ZHANG Ruiyun; HONG Kunlun; LUO Xiaolie

    1994-01-01

    In the present work, the structure and impact properties of copolymers of polypropylene with low ethylene contents have been investigated. Based on the results of 13C-NMR, FTIR,WAXD, DSC, PLM and SEM, the relationship between impact properties and morphology of the copolymers has been discussed. The high impact properties of copolymer ICP2 may attribute to the relatively higher ethylene content and homogeneous ethylene unit distribution. The size and its distribution of spherulite in the copolymers and cycloid cavities dispersed in polypropylene continue phase may also be two important factors which affect the impact properties of these materials.

  14. Impact velocity vs. target hardness relationships for equivalent response of cask structures

    International Nuclear Information System (INIS)

    In this paper, impact velocity vs. target hardness relationships for cask structures are reviewed. The relationships are based on equivalent cask responses in terms of equal deceleration or similar cask damages. By examining several past cask or container tests as well as some analytical results, some conclusions can be drawn about the relationship between target hardness and equivalent impact velocities. This relationship clearly shows that the cask response to impact is cask-dependent and that the rigid sphere impact model results in an unconservative estimate of equivalent velocity

  15. Gravitationally induced particle production and its impact on structure formation

    CERN Document Server

    Nunes, Rafael C

    2016-01-01

    In this paper we investigate the influence of a continuous particles creation processes on the linear and nonlinear matter clustering, and its consequences on the weak lensing effect induced by structure formation. We study the line of sight behavior of the contribution to the bispectrum signal at a given angular multipole $l$, showing that the scale where the nonlinear growth overcomes the linear effect depends strongly of particles creation rate.

  16. The Impact of Structural Prescriptions on Joint Venture Survival

    OpenAIRE

    Jeffrey Kaufmann; Hugh M. OÕNeill; ANNE S. YORK

    2006-01-01

    Prior research on joint ventures using both legal and strategic perspectives provides several transaction cost-based prescriptions for structuring joint ventures to minimize the threat of opportunistic behavior by venture partners. However, the effects of these prescriptions on the subsequent survival of the alliance are largely untested. Using survey data from senior managers responsible for alliance participation to explore these relationships, results show that many of the prescriptions th...

  17. IMPACT OF ALTERNATIVE GRID PRICING STRUCTURES ON CATTLE MARKETING DECISIONS

    OpenAIRE

    Greer, Heather C.; Trapp, James N.

    2000-01-01

    Quality grade, yield grade, and other feedlot performance factors explain much of the variation in profit under grid pricing. Thus, feedlot owners can change profits by adjusting time on feed to influence these performance factors. This research uses growth models, logistic regression, and an optimization process to determine how the optimal number of days on feed changes under different grid pricing structures. It was found that large quality or small yield discounts increases the optimal nu...

  18. Analytical studies on local damage to reinforced concrete structures under impact loading by discrete element method

    International Nuclear Information System (INIS)

    This paper proposes a new analytical approach for assessing local damage to reinforced concrete structures subjected to impact load, by applying the discrete element method (DEM). It first outlines the basis concept and analytical formulation of the DEM. Next, it discusses the results of simulation analyses of concrete material tests, uni-axial compression tests and tensile splitting tests conducted to determine appropriate analytical parameters such as material constants, failure criteria and strength increase factors depending on strain rate. Finally, the adaptability of the DEM to local damage to reinforced concrete structures impacted by rigid and deformable missiles is verified through simulation analyses of various types of impact tests. Furthermore, the various impact response characteristics and failure mechanisms, such as impact forces, penetration behavior, reduction in missile velocity and energy transfer process, which are difficult to obtain experimentally, are analytically evaluated by the DEM. (orig.)

  19. An FBG-Based Impact Event Detection System for Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    C. S. Shin

    2010-01-01

    Full Text Available Some structures are vulnerable to localized internal damages incurred by impact of small objects. An impact monitoring system using fiber Bragg grating (FBG sensors has been established. Its ability to detect very low to medium energy impacts has been demonstrated on an aluminum plate and a 22 m long wind turbine blade. Previous analysis of this technique showed that the accuracy by which an impact position can be located is limited by equipment noises and angular insensitivity of the FBG. By employing two intensity demodulation schemes with different demodulation sensitivities and ranges, we try to differentiate the relative importance of the above limiting effects. Based on the results, directions for further improvement on impact source locating accuracy will be discussed and the implication of applying such systems on large-scale structures will be examined.

  20. ANALYSIS ON IMPACT RESPONSES OF UNRESTRAINED PLANAR FRAME STRUCTURE(Ⅱ)-NUMERICAL EXAMPLE ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    CHEN Rong; ZHENG Hai-tao; XUE Song-tao; TANG He-sheng

    2005-01-01

    By using the formula derived in Part (Ⅰ), the instant response of an unrestrained planar frame structure subjected to the impact of a moving rigid-body are evaluated and analysed.The impact force-time history between the structure and the moving rigid-body, shear force and bending moment distribution along the beams, axial force distribution along the bars were calculated. The wave propagation phenomena of the longitudinal wave in the bars, the flexural and shear waves in the beams were also analysed. The numerical results show that the time duration of impact force is controlled by the flexural wave and the longitudinal wave; the shear effect in beams should not be neglected in the impact response analysis of structures.

  1. Designing, implementing and monitoring social impact mitigation strategies: Lessons from Forest Industry Structural Adjustment Packages

    International Nuclear Information System (INIS)

    Social impact mitigation strategies are implemented by the proponents of policies and projects with the intent of reducing the negative, and increasing the positive social impacts of their activities, and facilitating the achievement of policy/project goals. Evaluation of mitigation strategies is critical to improving their future success and cost-effectiveness. This paper evaluates two Forest Industry Structural Adjustment Packages (FISAP) implemented in Australia in the 1990s to 2000s as part of broader policy changes that reduced access to timber from publicly owned native forests. It assesses the effectiveness of the structure, design, implementation and monitoring of the FISAPs, and highlights the interactions between these four elements and their influence on social impacts. The two FISAPs were found to be effective in terms of reducing negative impacts, encouraging positive impacts and contributing towards policy goals, although they did not mitigate negative impacts in all cases, and sometimes interacted with external factors and additional policy changes to contribute to significant short and long term negative impacts. -- Highlights: ► Mitigation strategies aim to reduce negative and enhance positive social impacts ► Mitigation strategy design, implementation, and monitoring are critical to success ► Effective mitigation enhanced the capacity of recipients to respond to change ► Mitigation strategies influenced multiple interacting positive and negative impacts ► Success required good communication, transparency, support, resources and timing

  2. Experiencing the Impact of Organizational Structure on Planning and Visioning Tasks

    Science.gov (United States)

    Pennisi, Lisa

    2012-01-01

    The various ways natural resource agencies and programs are structured and how that impacts leadership style and products is an important concept for students to understand. Leadership style and organizational structure determine visions, missions, goals and objectives that set the tone for organizations. This exercise demonstrates organizational…

  3. The Impact of Structured Teaching Methods on the Quality of Education in Brazil

    Science.gov (United States)

    Leme, Maria Carolina; Louzano, Paula; Ponczek, Vladimir; Souza, Andre Portela

    2012-01-01

    This paper estimates the impact of the use of structured methods on the quality of education for students in primary public school in Brazil. Structured methods encompass a range of pedagogical and managerial instruments applied in the educational system. In recent years, several municipalities in the state of Sao Paulo have contracted out private…

  4. Review on Empirical Studies of Local Impact Effects of Hard Missile on Concrete Structures

    Directory of Open Access Journals (Sweden)

    Ismail Abdul Rahman

    2011-05-01

    Full Text Available Concrete is basic construction material used for any kind of structure. However, in most vital and local structures such as nuclear plants, Power plants, Weapon Industries, weapons storage places, water retaining structures like dams, and also local industries, & etc., concrete structures have to be designed as defensive structures to provide protection against any accidents or knowingly generated incidents such as dynamic loading, dynamic local impact damage and global damage generated by kinetic missiles (steel rods, steel pipes, turbine blades, etc.. The impacting missile (projectile can be classified as ‘Hard’ and ‘Soft’ in nature, depending upon the implication of its deformation with respect to the deformation of target. ‘Hard’ missile impact can generate both local impact damage and also overall dynamic global damage of concrete structure. This paper only provides the review of previous empirical studies related to our study and can be used for making design recommendation and design procedures for determining the dynamic response of the target to prevent local and impact damage.

  5. Humic Substances from Manila Bay and Bolinao Bay Sediments

    Directory of Open Access Journals (Sweden)

    Elma Llaguno

    1997-12-01

    Full Text Available The C,H,N composition of sedimentary humic acids (HA extracted from three sites in Manila Bay and six sites in Bolinao Bay yielded H/C atomic ratios of 1.1-1.4 and N/C atomic ratios of 0.09 - 0.16. The Manila Bay HA's had lower H/C and N/C ratios compared to those from Bolinao Bay. The IR spectra showed prominent aliphatic C-H and amide I and II bands. Manila Bay HA's also had less diverse molecular composition based on the GC-MS analysis of the CuO and alkaline permanganate oxidation products of the humic acids.

  6. The Impact of Embedded Story Structures versus Sequential Story Structures on Critical Thinking of Iranian Intermediate EFL Learners

    Directory of Open Access Journals (Sweden)

    Sara Samadi

    2016-09-01

    Full Text Available Confirming the constructive effects of reading comprehension on critical thinking, this paper attempted to investigate the impact of story structures on critical thinking of Iranian EFL learners. In doing so, the researcher utilized a quasi–experimental design with 60 intermediate students who were divided into two embedded story structures and sequential story structures groups (experimental groups. After taking PET, a critical thinking questionnaire was employed as a pre-test. The two groups received 16 sessions of treatment. All participants received similar amount of instruction but one group was given embedded short stories and the other group sequential short stories. To compare the two groups, they were received the parallel critical thinking questionnaire as a post-test. The two null hypotheses in this study were rejected due to different performance of the two groups. Statistical results did not support the superiority of neither structures. Therefore, the researcher was not able to suggest which structure caused a better or higher impact on critical thinking. However, the findings reveal that teaching story structures in EFL context can develop critical thinking of intermediate EFL learners. The study have some implications for test-designers, teachers, and students.Keywords: Critical thinking, Embedded story structure, Sequential story structure, Reading comprehension

  7. Impact of pion dynamics on nuclear shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Litvinova, Elena, E-mail: elena.litvinova@wmich.edu [Department of Physics, Western Michigan University, Kalamazoo, MI 49008-5252 (United States); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States)

    2015-10-15

    Spin-isospin response in exotic nuclear systems is investigated. It is found that in some nuclei excitations with pionic quantum numbers (0{sup −}, 1{sup +}, 2{sup −}, …) appear at very low energies with large transition probabilities, which is an indication of the vicinity of the onset of pion condensation. As an example, 2{sup −} components of the spin-dipole resonance in {sup 78}Ni and {sup 132}Sn are considered. The existence of such modes points out to the necessity of taking into account their coupling to other elementary modes of excitation, e.g. single-quasiparticle ones. This coupling is introduced in the theory for the first time. Thereby, both rho-meson and pion-exchange contributions to the nucleon-nucleon interaction are included in the relativistic framework beyond the Hartree-Fock approximation. Namely, classes of Feynman diagrams are selected according to their significance for nuclear spectroscopic characteristics, such as single-particle energies and strength functions, and included into the nucleonic self-energy in all orders of meson-exchange. As an illustration, the impact of these new contributions on the single-particle energies of {sup 100}Sn is discussed.

  8. Impact of metal pollution on fungal diversity and community structures.

    Science.gov (United States)

    Op De Beeck, Michiel; Lievens, Bart; Busschaert, Pieter; Rineau, Francois; Smits, Mark; Vangronsveld, Jaco; Colpaert, Jan V

    2015-06-01

    The impact of metal pollution on plant communities has been studied extensively in the past, but little is known about the effects of metal pollution on fungal communities that occur in metal-polluted soils. Metal-tolerant ecotypes of the ectomycorrhizal fungus Suillus luteus are frequently found in pioneer pine forests in the Campine region in Belgium on metal-polluted soils. We hypothesized that metal pollution would play an important role in shaping below-ground fungal communities that occur in these soils and that Suillus luteus would be a dominant player. To test these hypotheses, the fungal communities in a young pine plantation in soil polluted with zinc, and cadmium were studied using 454 amplicon pyrosequencing. Results show that zinc, cadmium and soil organic matter content were strongly correlated with the fungal community composition, but no effects on fungal diversity were observed. As hypothesized, S. luteus was found to be a dominant member of the studied fungal communities. However, other dominant fungal species, such as Sistotrema sp., Wilcoxina mikolae and Cadophora finlandica were found as well. Their presence in metal-polluted sites is discussed. PMID:24947496

  9. Impact of pion dynamics on nuclear shell structure

    International Nuclear Information System (INIS)

    Spin-isospin response in exotic nuclear systems is investigated. It is found that in some nuclei excitations with pionic quantum numbers (0−, 1+, 2−, …) appear at very low energies with large transition probabilities, which is an indication of the vicinity of the onset of pion condensation. As an example, 2− components of the spin-dipole resonance in 78Ni and 132Sn are considered. The existence of such modes points out to the necessity of taking into account their coupling to other elementary modes of excitation, e.g. single-quasiparticle ones. This coupling is introduced in the theory for the first time. Thereby, both rho-meson and pion-exchange contributions to the nucleon-nucleon interaction are included in the relativistic framework beyond the Hartree-Fock approximation. Namely, classes of Feynman diagrams are selected according to their significance for nuclear spectroscopic characteristics, such as single-particle energies and strength functions, and included into the nucleonic self-energy in all orders of meson-exchange. As an illustration, the impact of these new contributions on the single-particle energies of 100Sn is discussed

  10. Impact of fatty acids on brain circulation, structure and function.

    Science.gov (United States)

    Haast, Roy A M; Kiliaan, Amanda J

    2015-01-01

    The use of dietary intervention has evolved into a promising approach to prevent the onset and progression of brain diseases. The positive relationship between intake of omega-3 long chain polyunsaturated fatty acids (ω3-LCPUFAs) and decreased onset of disease- and aging-related deterioration of brain health is increasingly endorsed across epidemiological and diet-interventional studies. Promising results are found regarding to the protection of proper brain circulation, structure and functionality in healthy and diseased humans and animal models. These include enhanced cerebral blood flow (CBF), white and gray matter integrity, and improved cognitive functioning, and are possibly mediated through increased neurovascular coupling, neuroprotection and neuronal plasticity, respectively. Contrary, studies investigating diets high in saturated fats provide opposite results, which may eventually lead to irreversible damage. Studies like these are of great importance given the high incidence of obesity caused by the increased and decreased consumption of respectively saturated fats and ω3-LCPUFAs in the Western civilization. This paper will review in vivo research conducted on the effects of ω3-LCPUFAs and saturated fatty acids on integrity (circulation, structure and function) of the young, aging and diseased brain. PMID:24485516

  11. Chemical precipitation structures formed by drops impacting on a deep pool

    Science.gov (United States)

    Kaminker, V.; Maselko, J.; Pantaleone, J.

    2012-11-01

    The experiments described here are at the intersection of two dynamical systems with long pedigrees for forming interesting patterns: liquid droplet impacts and precipitation membranes. Drops of calcium chloride solution have been allowed to impact on a deep pool of sodium silicate solution. The precipitation structures produced by this method, and how these structures subsequently evolve, have been observed. Many interesting patterns can be formed from this process. It is observed that the precipitation patterns produced are sensitive to the shape of the drop when it impacts the pool's surface. Also, at large drop heights, we determine two critical Weber numbers: one for forming a skirt around the structures and the other for breakup of the structures. On longer time scales, open tubes grow from the closed precipitation shell produced at lower drop heights. These tubes can appear in large numbers with nearly identical sizes and diameters as small as 50 μm.

  12. Long-term threats to Canada's James Bay from hydroelectric development

    International Nuclear Information System (INIS)

    The steep gradients on the Quebec side of James Bay make the area attractive for hydroelectric development. Most of the major rivers in this area will eventually be affected by the development plans of Hydro-Quebec. Environmental studies maintain that changes to the bay from exising hydroelectric developments have been fewer than expected and that many physical parameters in the bay are insensitive to river flows. However, future cumulative impacts may be more negative. The Canadian environmental review process for James Bay hydro developments has not considered either cumulative impacts or alternatives to the projects, including the alternative of not building them at all. The weakness of the environmental review process has serious implications for James Bay. Projects receiving federal funding or on federal land are subject to review, but these conditions do not apply to Hydro-Quebec's projects. Nevertheless, the National Energy Board (NEB) has jurisdiction over electrical exports, and has historically considered environmental impacts of generating plants and transmission lines related to electrical exports when approvals for such exports are sought. Public pressure from environmental organizations has been mounting to reevaluate James Bay plans in light of possible cumulative impacts. In addition, there are possibilities of using US legislation on electricity imports to press for environmental review of the impact of electricity exports from James Bay. 10 refs

  13. Relationship between structural parameters and the Neel temperature in Sr1-xCaxMnO3 (0≤xle1) and Sr1-yBayMnO3 (y≤0.2)

    International Nuclear Information System (INIS)

    The crystal and magnetic structures of newly synthesized Sr1-xCaxMnO3 (0≤x le 1) and Sr1-yBayMnO3 (y≤0.2) perovskite materials (of the ABO3 type) were investigated using neutron and synchrotron x-ray powder diffraction at temperatures between 10 and 530 K. Upon decreasing the size of the A-site ion (or the unit-cell size) a series of structural transitions appears at room temperature from cubic Pmbar 3m to tetragonal I4/mcm (at x∼0.3) to orthorhombic Pbnm at x∼0.4. In agreement with neutron-diffraction data, resistive and magnetic measurements show that the samples are antiferromagnetic with Neel temperatures TN, varying from 233 to ∼125 K and from 233 to 212 K by increasing the Ca and Ba contents, respectively. The observed variation of TN cannot be solely explained by the changes of the unit-cell size or the average Mn-O-Mn bond angle θ. The behavior of TN can be satisfactorily described as a function of 2 θ> related to the superexchange interaction integral, and σ2, the A-site ionic size variance [L. M. Rodriguez-Martinez and J. P. Attfield, Phys. Rev. B 54, R15 622 (1996)] regardless of the structural symmetry of the perovskite material

  14. Effect of block copolymer nano-reinforcements on the low velocity impact response of sandwich structures

    OpenAIRE

    RAMAKRISHNAN, Karthik Ram; GUERARD, Sandra; Viot, Philippe; SHANKAR, Krishna

    2014-01-01

    Sandwich composites with fibre reinforced plastic (FRP) facesheets have emerged as a major class of lightweight structural materials in a wide range of engineering fields including aerospace, automotive and marine structures. This is due to attractive mechanical properties such as high specific stiffness and high strength. However, sandwich structures are susceptible to damage caused by impact. The objective of this paper is to evaluate the dynamic response of sandwich composites based on Kev...

  15. THE IMPACT OF COMPENSATION PAYMENTS ON EMPLOYMENT, IN REGIONAL STRUCTURES

    Directory of Open Access Journals (Sweden)

    Nicoleta JULA

    2015-07-01

    Full Text Available Compensation payments are considered active labour market policies designed to increase efficiency, to mitigate unemployment and to sustaining employment. We tested this hypothesis for the period 1993-2013, in territorial structures (42 counties through a dynamic panel model (confirmed by Granger causality tests – Toda-Yamamoto version, and by means of error correction model. We found that the dynamics of regional employment are positively related to expenditure incurred for active policies and there are negatively correlated with the ratio between the unemployment average indemnity (and support allowance and the average net nominal monthly salary earnings. But, the connexion between employment and compensation payments converges extremely slowly for a long-term stable relationship.

  16. Impact of Aerodynamics and Structures Technology on Heavy Lift Tiltrotors

    Science.gov (United States)

    Acree, C. W., Jr.

    2006-01-01

    Rotor performance and aeroelastic stability are presented for a 124,000-lb Large Civil Tilt Rotor (LCTR) design. It was designed to carry 120 passengers for 1200 nm, with performance of 350 knots at 30,000 ft altitude. Design features include a low-mounted wing and hingeless rotors, with a very low cruise tip speed of 350 ft/sec. The rotor and wing design processes are described, including rotor optimization methods and wing/rotor aeroelastic stability analyses. New rotor airfoils were designed specifically for the LCTR; the resulting performance improvements are compared to current technology airfoils. Twist, taper and precone optimization are presented, along with the effects of blade flexibility on performance. A new wing airfoil was designed and a composite structure was developed to meet the wing load requirements for certification. Predictions of aeroelastic stability are presented for the optimized rotor and wing, along with summaries of the effects of rotor design parameters on stability.

  17. Impact of bacterial endotoxin on the structure of DMPC membranes.

    Science.gov (United States)

    Nagel, Michael; Brauckmann, Stephan; Moegle-Hofacker, Franzeska; Effenberger-Neidnicht, Katharina; Hartmann, Matthias; de Groot, Herbert; Mayer, Christian

    2015-10-01

    Bacterial lipopolysaccharides are believed to have a toxic effect on human cell membranes. In this study, the influence of a lipopolysaccharide (LPS) from Escherichia coli on the structure, the dynamics and the mechanical strength of phospholipid membranes are monitored by nuclear magnetic resonance spectroscopy (NMR) and by atomic force microscopy (AFM). Model membranes are formed from 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and are either prepared as multilamellar bulk samples or multilamellar vesicles. Field gradient NMR data directly prove the rapid integration of LPS into DMPC membranes. Solid state NMR experiments primarily detect decreasing molecular order parameters with increasing LPS content. This is accompanied by a mechanical softening of the membrane bilayers as is shown by AFM indentation measurements. Altogether, the data prove that lipopolysaccharide molecules quickly insert into phospholipid bilayers, increase membrane fluctuation amplitudes and significantly weaken their mechanical stiffness. PMID:26071197

  18. Synthesis and Structure Control of A New Kind of Inelastomer Impact Modifier with Core-shell Structure and Impact Modification to PVC/CPE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new kind of inelastomer impact modifier with a core-shell structure was synthesized by employing a multi-step composite emulsion polymerization technique, the size and morphology structure of the core-shell particles could be controlled by the multi-step composite emulsion polymerization technique. The study of the impact strength and the elongation at break of the PVC/CPE blend with different contents of core-shell particles(C-S) indicated that the mechanical properties of PVC/CPE/C-S composite were the best when the concentration of the particle was 2.5%(mass fraction) which showed the different regularities and characteristics of elastomer toughening plastic.

  19. Evaluation of the Impact of the EU Structural Support on the Competitiveness of Lithuanian Economics

    Directory of Open Access Journals (Sweden)

    Rita Remeikiene

    2016-06-01

    Full Text Available Increasing amounts of the EU structural support in Lithuania require theoretical and practical research to disclose the determinants that have a significant impact on the competitiveness of Lithuanian economics. The purpose of this article is to evaluate the impact of the EU structural support on the competitiveness of Lithuanian economics. The methods of the research include systematic and comparative analysis of the scientific literature, expert evaluation and linear regression. The research disclosed the main determinants of country’s competitiveness. The results have revealed that EU structural support has the most significant impact on Lithuanian engineering and technological infrastructure. The impact of the support on country’s macroeconomic, scientific and social environment can also be considered as significant. The EU structural support has medium strong impact on education and business environment conditions in Lithuania. It has been established that, in the field of business advancement, Lithuanian should be rated as medium competitive. Hence, the increase in country’s competitiveness by employing EU structural funds should be treated as one of priority aims. In addition, responsible authorities should perform with higher efficiency seeking for higher competitiveness of the country.

  20. Local Impact Simulation of SC Wall Structures using Aircraft Engine Projectile

    International Nuclear Information System (INIS)

    SC wall structure developed for nuclear power plant buildings consists of plain concrete and two steel plates on both surface of the concrete, while RC structure consists of re bar and concrete. SC structure has higher scabbing resistance than RC structure due to the action of steel plate on the rear side of impact. Therefore SC structure is known as more effective structure from the viewpoint of aircraft crash than RC structure. However, most of the recent researches and experiments about local impact damage deal with RC structures, and the effect of re bar and steel plate is not considered reasonably. Although Walter et al. and Make-work et al. suggested a formula for evaluating perforation depth of steel plate covered RC walls, most of the previous researches about SC structure are focused on perforation and scabbing due to the impact of hard projectile, rather than soft projectile such as an aircraft. In this research a soft projectile, i. e. aircraft engine, is utilized for impact simulation of RC and SC walls. To evaluate local damage of SC wall structures, parametric study with the variables of wall thickness and steel ratio of the cover plate is performed, and the results are compared with those of RC structures. Since scabbing was prevented by the steel plates, penetration mode of damage was observed in SC walls while scabbing damage was occurred in RC walls. It is confirmed that the rear steel plate not only contains concrete debris, but also reduces the internal damage of the concrete walls. Penetration depth of SC walls did not largely vary due to the increasing steel ratio, and similar results to RC walls were observed when the wall thickness is larger than a certain value since the impact resistance of SC wall is mainly governed by the thickness of concrete part. Therefore, it is expected that similar level of impact resistance to RC structure can be produced with the minimum thickness of steel plates of SC structure. According to these results, SC

  1. Workplace experience of radiographers: impact of structural and interpersonal interventions

    Energy Technology Data Exchange (ETDEWEB)

    Kubik-Huch, R.A.; Roempler, M.; Weber, A. [Kantonsspital Baden, Institute of Radiology, Baden (Switzerland); Klaghofer, R.; Buddeberg-Fischer, B. [Zurich University Hospital, Department of Psychosocial Medicine, Zurich (Switzerland)

    2010-02-15

    Within the framework of organisational development, an assessment of the workplace experience of radiographers (RGs) was conducted. The aims of this study were to develop structural and interpersonal interventions and to prove their effectiveness and feasibility. A questionnaire consisting of work-related factors, e.g. time management and communication, and two validated instruments (Workplace Analysis Questionnaire, Effort-Reward Imbalance Scale) was distributed to all RGs (n = 33) at baseline (T1). Interventions were implemented and a follow-up survey (T2) was performed 18 months after the initial assessment. At T1, areas with highest dissatisfaction were communication and time management for ambulant patients (bad/very bad, 57% each). The interventions addressed adaptation of work plans, coaching in developing interpersonal and team leadership skills, and regular team meetings. The follow-up survey (T2) showed significantly improved communication and cooperation within the team and improved qualification opportunities, whereas no significant changes could be identified in time management and in the workplace-related scales 'effort' expended at work and 'reward' received in return for the effort. Motivating workplace experience is important for high-level service quality and for attracting well-qualified radiographers to work at a place and to stay in the team for a longer period. (orig.)

  2. Workplace experience of radiographers: impact of structural and interpersonal interventions

    International Nuclear Information System (INIS)

    Within the framework of organisational development, an assessment of the workplace experience of radiographers (RGs) was conducted. The aims of this study were to develop structural and interpersonal interventions and to prove their effectiveness and feasibility. A questionnaire consisting of work-related factors, e.g. time management and communication, and two validated instruments (Workplace Analysis Questionnaire, Effort-Reward Imbalance Scale) was distributed to all RGs (n = 33) at baseline (T1). Interventions were implemented and a follow-up survey (T2) was performed 18 months after the initial assessment. At T1, areas with highest dissatisfaction were communication and time management for ambulant patients (bad/very bad, 57% each). The interventions addressed adaptation of work plans, coaching in developing interpersonal and team leadership skills, and regular team meetings. The follow-up survey (T2) showed significantly improved communication and cooperation within the team and improved qualification opportunities, whereas no significant changes could be identified in time management and in the workplace-related scales 'effort' expended at work and 'reward' received in return for the effort. Motivating workplace experience is important for high-level service quality and for attracting well-qualified radiographers to work at a place and to stay in the team for a longer period. (orig.)

  3. Nonindigenous marine species in Kaneohe Bay, Oahu, Hawaii in 1999 - 2000 (NODC Accession 0001053)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The presence and impact of nonindigenous (introduced) marine organisms in Kaneohe Bay, Oahu, Hawaiian Islands are evaluated using a combination of historical...

  4. 77 FR 45991 - Regulated Navigation Area; Buzzard's Bay, MA; Navigable Waterways Within the First Coast Guard...

    Science.gov (United States)

    2012-08-02

    ...The Coast Guard announces the availability of a draft Environmental Assessment (EA) considering the reasonably foreseeable environmental impacts and socioeconomic effects of implementing a Regulated Navigation Area in Buzzard's Bay, MA. We request your comments on the draft...

  5. Impact Response of Aluminum Foam Sandwiches for Light-Weight Ship Structures

    Directory of Open Access Journals (Sweden)

    Eugenio Guglielmino

    2011-12-01

    Full Text Available The structures realized using sandwich technologies combine low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry where the “lightweight design” philosophy and the safety of vehicles are very important aspects. While sandwich structures with polymeric foams have been applied for many years, currently there is a considerable and growing interest in the use of sandwiches with aluminum foam core. The aim of this paper was the analysis of low-velocity impact response of AFS (aluminum foam sandwiches panels and the investigation of their collapse modes. Low velocity impact tests were carried out by a drop test machine and a theoretical approach, based on the energy balance model, has been applied to investigate their impact behavior. The failure mode and the internal damage of the impacted AFS have also been investigated by a Computed Tomography (CT system.

  6. On a digital wireless impact-monitoring network for large-scale composite structures

    International Nuclear Information System (INIS)

    Impact, which may occur during manufacture, service or maintenance, is one of the major concerns to be monitored throughout the lifetime of aircraft composite structures. Aiming at monitoring impacts online while minimizing the weight added to the aircraft to meet the strict limitations of aerospace engineering, this paper puts forward a new digital wireless network based on miniaturized wireless digital impact-monitoring nodes developed for large-scale composite structures. In addition to investigations on the design methods of the network architecture, time synchronization and implementation method, a conflict resolution method based on the feature parameters of digital sequences is first presented to address impact localization conflicts when several nodes are arranged close together. To verify the feasibility and stability of the wireless network, experiments are performed on a complex aircraft composite wing box and an unmanned aerial vehicle (UAV) composite wing. Experimental results show the successful design of the presented network. (paper)

  7. [Impact of energy related pollutants on chromosome structure]: Progress report

    International Nuclear Information System (INIS)

    Studies of the structure of nucleosome cores using chymotrypsin as a probe of hydrophobic residues showed that only leu-20 of H3 was readily accessible. Primary sites of cleavage of H2a, H2b, and H4 were identified. Chymotrypsin removal of specific histone termini showed that removal of the amino-terminal plus the carboxy-terminal 13 residues of H2a caused little unfolding. Using carbon-13 NMR spectroscopic, about 10% of histone amino acid residues were found to be in termini that are highly mobile. The major mobile segments were amino terminal regions of H3 and H2a, plus a carboxy-terminal region of H2a. The histone variants and developmental changes during embryogenesis of sea urchin were characterized. The early histone gene organization in L. variegatus was characterized, a genomic library was cloned in lambda phage, and several histone gene clones were selected. The nucleosome core length DNA forms crystalline phases at physiological concentrations. Microscopic and NMR spectroscopic methods were used to identify crystalline phases and to establish phase diagrams for transitions between phases as functions of DNA concentration and temperature. The sequence specificities of binding of several polycyclic aromatic chemicals to early H3 and H2a genes were examined. Chemicals studied were the bis-(o-phenanthroline) Cu(I) complex, AAAF, benzopyrene dihydrodiol epoxide, methylene blue, and acridine orange A preliminary map of binding sites of CuOP, AAAF and BPDE in and near the H3 gene showed that several sequence regions were bound preferentially by two or more of these chemicals. CuOP appeared to exhibit the most specificity. 80 refs., 4 figs

  8. Radioecological status of terrestrial and aquatic systems in Andreev Bay

    International Nuclear Information System (INIS)

    Paper describes radioecological situation at the naval shore unit located at the Andreev Bay. One discusses the results of analysis of both the potential and the real danger sources and the measures to prevent adverse impact on the environment and on the personnel in the course of remediation efforts

  9. BENTHIC MACROFAUNA AND HABITAT RELATIONSHIPS IN TILLAMOOK BAY

    Science.gov (United States)

    Tillamook Bay is subject to natural and man-made stressors, such as increased nutrients and sediments, which can alter its habitats and, thereby, impact its productivity and ecological resources. The benthic macrofauna are small, sediment-dwelling invertebrates which have strong...

  10. Modelling of low energy/low velocity impact on Nomex honeycomb sandwich structures with metallic skins

    OpenAIRE

    Castanié, Bruno; Bouvet, Christophe; Aminanda, Yulfian; Barrau, Jean-Jacques; Thévenet, Pascal

    2008-01-01

    In the aircraft industry, manufacturers have to decide quickly whether an impacted sandwich needs repairing or not. Certain computation tools exist at present but they are very time-consuming and they also fail to perfectly model the physical phenomena involved in an impact. In a previous publication, the authors demonstrated the possibility of representing the NomexTM honeycomb core by a grid of nonlinear springs and have pointed out both the structural behaviour of the honeycomb and the ...

  11. Fe mineralogy of rocks from the Vredefort impact structure investigated with Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    The Vredefort impact structure in South Africa is the largest and oldest remnant impact structure on Earth. Observations from above the crater reveal lower than average magnetic field intensities, but the rocks in the crater have been shown to possess much higher magnetic intensities than the regional average that varies on a centimeter scale. Various mechanisms, including the presence of single domain magnetite structures, have been proposed for this anomaly. Moessbauer spectroscopy has been applied to study the Fe-mineralogy of samples from near the centre of the Vredefort crater. Transmission Moessbauer measurements on bulk and microtomics sections of samples showed that the magnetic minerals were magnetite and hematite, and we suggest that oxidation of olivine during the impact is responsible for the magnetic properties of the rocks.

  12. Energy Analysis for TMD-Structure Systems Subjected to Impact Loading

    Institute of Scientific and Technical Information of China (English)

    王树青; 李华军; 嵇春艳; 焦桂英

    2002-01-01

    This paper investigates the characteristics of reduction of the lateral vibration by use of a Tuned Mass Damper(TMD) for offshore jacket platforms under impact loading. Unlike traditional analysis, the present analysis focnses on theenergy concept of TMD/structure systems. In this study, a time domain is taken. The platform is modeled as a simplifiedsingle-degree-of-freedom (SDOF) system by extraction of the first vibration mode of the structure and the excited force isassumed to be impact loading. The energy dissipation and energy transmission of the structure-TMD system are studied.Finally, an optimized TMD design for the modeled platform is demonstrated based on a new type of cost function - maxi-mum dissipated energy by TMD. Results indicate that TMD control is effective in reducing the standard deviation of thedeck motion but less effective in reducing the maximum response under impact loading.

  13. Shatter cones at the Keurusselkä impact structure and their relation to local jointing

    Science.gov (United States)

    Hasch, Maximilian; Reimold, Wolf Uwe; Raschke, Ulli; Zaag, Patrice Tristan

    2016-08-01

    Shatter cones are the only distinct meso- to macroscopic recognition criterion for impact structures, yet not all is known about their formation. The Keurusselkä impact structure, Finland, is interesting in that it presents a multitude of well-exposed shatter cones in medium- to coarse-grained granitoids. The allegedly 27 km wide Keurusselkä impact structure was formed about 1150 Ma ago in rocks of the Central Finland Granitoid Complex. Special attention was paid in this work to possible relationships between shatter cones and local, as well as regionally occurring, fracture or joint systems. A possible shatter cone find outside the previously suggested edge of the structure could mean that the Keurusselkä impact structure is larger than previously thought. The spacing between joints/fractures from regional joint systems was influenced by the impact, but impact-induced fractures strongly follow the regional joint orientation trends. There is a distinct relationship between shatter cones and joints: shatter cones occur on and against joint surfaces of varied orientations and belonging to the regional orientation trends. Planar fractures (PF) and planar deformation features (PDF) were found in three shatter cone samples from the central-most part of the impact structure, whereas other country rock samples from the same level of exposure but further from the assumed center lack shock deformation features. PDF occurrence is enhanced within 5 mm of shatter cone surfaces, which is interpreted to suggest that shock wave reverberation at preimpact joints could be responsible for this local enhancement of shock deformation. Some shatter cone surfaces are coated with a quasi-opaque material which is also found in conspicuous veinlets that branch off from shatter cone surfaces and resemble pseudotachylitic breccia veins. The vein-filling is composed of two mineral phases, one of which could be identified as a montmorillonitic phyllosilicate. The second phase could not be

  14. A Creek to Bay Biological Assessment in Oakland, California

    Science.gov (United States)

    Ahumada, E.; Ramirez, N.; Lopez, A.; Avila, M.; Ramirez, J.; Arroyo, D.; Bracho, H.; Casanova, A.; Pierson, E.

    2011-12-01

    In 2007, the Surface Water Ambient Monitoring Program (SWAMP) assessed the impact of trash on water quality in the Peralta Creek which is located in the Fruitvale district of Oakland, CA. This 2011 follow-up study will take further steps in evaluating the physical and biological impacts of pollution and human development on Peralta Creek and in the San Leandro Bay, where the Creek empties into the larger San Francisco Bay estuary. This study will utilize two forms of biological assessment in order to determine the level of water quality and ecosystem health of Peralta Creek and San Leandro Bay in Oakland, California. A Rapid Bioassesment Protocal (RBP) will be used as the method of biological assessment for Peralta Creek. RBP uses a biotic index of benthic macroinvertebrates to provide a measure of a water body's health. Larval trematodes found in two mud snails (Ilynassa obsoleta and Cerithidea californica) will be used to evaluate the health of the San Leandro Bay. Due to the complex life cycle of trematodes, the measure of trematode diversity and richness in host species serves as an indicator of estuarine health (Huspeni 2005). We have completed the assessment of one section of Peralta Creek, located at 2465 34th Avenue, Oakland, CA 94601. Abundance results indicate a moderately healthy creek because there were high levels of pollution tolerant benthic macroinvertebrates. The tolerant group of benthic macroinvertebrates includes such organisms as flatworms, leeches, and scuds. This is possibly due to this section of the creek being pumped up to the surface from culverts impacting the macroinvertebrate's life cycle. Another contributing factor to creek health is the amount of organic debris found in the creek, which inhibits the flow and oxygenation of the water, allowing for more pollution tolerant aquatic insects to persist. Further investigation is being conducted to fully assess the Peralta Creek watershed; from the preliminary results one can surmise that

  15. Microbial colonization in impact-generated hydrothermal sulphate deposits, Haughton impact structure, and implications for sulphates on Mars

    Science.gov (United States)

    Parnell, J.; Lee, P.; Cockell, C. S.; Osinski, G. R.

    2004-07-01

    Hydrothermal gypsum deposits in the Haughton impact structure, Devon Island, Canada, contain microbial communities in an endolithic habitat within individual gypsum crystals. Cyanobacterial colonies occur as masses along cleavage planes, up to 5 cm from crystal margins. The crystals are transparent, so allow transmission of light for photosynthesis, while affording protection from dehydration and wind. The colonies appear to have modified their mineral host to provide additional space as they expanded. The colonies are black due to UV-screening pigments. The relative ease with which microbial colonization may be detected and identified in impact-generated sulphate deposits at Haughton suggests that analogous settings on other planets might merit future searches for biosignatures. The proven occurrence of sulphates on the Martian surface suggests that sulphate minerals should be a priority target in the search for life on Mars.

  16. Low-Cost Impact Detection and Location for Automated Inspections of 3D Metallic Based Structures

    Directory of Open Access Journals (Sweden)

    Carlos Morón

    2015-05-01

    Full Text Available This paper describes a new low-cost means to detect and locate mechanical impacts (collisions on a 3D metal-based structure. We employ the simple and reasonably hypothesis that the use of a homogeneous material will allow certain details of the impact to be automatically determined by measuring the time delays of acoustic wave propagation throughout the 3D structure. The location of strategic piezoelectric sensors on the structure and an electronic-computerized system has allowed us to determine the instant and position at which the impact is produced. The proposed automatic system allows us to fully integrate impact point detection and the task of inspecting the point or zone at which this impact occurs. What is more, the proposed method can be easily integrated into a robot-based inspection system capable of moving over 3D metallic structures, thus avoiding (or minimizing the need for direct human intervention. Experimental results are provided to show the effectiveness of the proposed approach.

  17. A compilation of structural property data for computer impact calculation (3/5)

    International Nuclear Information System (INIS)

    The paper describes structural property data for computer impact calculations of nuclear fuel shipping casks. Four kinds of material data, mild steel, stainless steel, lead and wood are compiled. These materials are main structural elements of shipping casks. Structural data such as, the coefficient of thermal expansion, the modulus of longitudinal elasticity, the modulus of transverse elasticity, the Poisson's ratio and stress and strain relationships, have been tabulated against temperature or strain rate. This volume 3 involve structural property data of stainless steel. (author)

  18. Impact of structure geometry on scattering in partially-ordered media

    International Nuclear Information System (INIS)

    Scattering in random structure is a typical problem for different media: colloids, clouds, liquids in coagulation stage, etc. In these structures, the group formation leads to interference effects in the scattered phase function due to the significant static structure factor. This work includes a computational study of the group formation impact on the radiation transfer in such media, when a point isotropic source is used. Rigorous calculations of a group scattering phase function for structures with different particle's size are made. A Monte-Carlo approach is applied to solve the radiative transfer equation in these media. To avoid singularities in the direct Monte-Carlo solution, appeared due to the radiation detection in a single point, the double-local Monte-Carlo estimation was used. The impact of group scattering phase function and a structure factor on the calculated scattered field radiance are discussed in this work. It is shown that for the point isotropic source the inhomogeneity of the group scattering phase function appears in the radiative transfer effects. - Highlights: • Multiple scattering in structured medium was modeled via Monte Carlo simulation. • Group formation impact on multiply scattered radiance was observed. • Static structure factor influence on scattered radiance was obtained. • Scattered radiance changes nonlinearly via number and size of particles in groups

  19. Water quality assessment in the Nha Trang Bay (Vietnam) by using in-situ and remotely sensed data

    OpenAIRE

    Phan Minh Thu, T; Schaepman, M. E.; Leemans, R.; Nguyen Tac An, A.; Tong Phuoc Hoang Son, S; Ngo Manh Tien, T; Phan Thanh Bac, B.

    2008-01-01

    The Nha Trang Bay (Vietnam) is an international marine protected area with significant economic, natural and recreational values. Considerable economic development is expected in particularly for tourism, navigation and aquaculture. However, in recent years the environmental quality of the Bay has been degraded by human activities and impacts. Even though the conditions of the Bay are monitored with in-situ measurements in a marine station, the environmental data, measured only in half-yearly...

  20. Review: Impact of underground structures on the flow of urban groundwater

    Science.gov (United States)

    Attard, Guillaume; Winiarski, Thierry; Rossier, Yvan; Eisenlohr, Laurent

    2016-02-01

    Property economics favours the vertical development of cities but flow of groundwater can be affected by the use of underground space in them. This review article presents the state of the art regarding the impact of disturbances caused by underground structures (tunnels, basements of buildings, deep foundations, etc.) on the groundwater flow in urban aquifers. The structures built in the underground levels of urban areas are presented and organised in terms of their impact on flow: obstacle to the flow or disturbance of the groundwater budget of the flow system. These two types of disturbance are described in relation to the structure area and the urban area. The work reviewed shows, on one hand, the individual impacts of different urban underground structures, and on the other, their cumulative impacts on flow, using real case studies. Lastly, the works are placed in perspective regarding the integration of underground structures with the aim of operational management of an urban aquifer. The literature presents deterministic numerical modelling as a tool capable of contributing to this aim, in that it helps to quantify the effect of an underground infrastructure project on groundwater flow, which is crucial for decision-making processes. It can also be an operational decision-aid tool for choosing construction techniques or for formulating strategies to manage the water resource.