WorldWideScience

Sample records for submarine fan deposits

  1. Process sedimentology of submarine fan deposits - new perspectives

    Science.gov (United States)

    Postma, George

    2017-04-01

    To link submarine fan process sedimentology with sand distribution, sand body architecture, texture and fabric, the field geologist studies sedimentary facies, facies associations (fan elements) and stratigraphy. Facies analysis resides on factual knowledge of modern fan morphodynamics and physical modelling of en-masse sediment transport. Where do we stand after 55 years of submarine research, i.e. the date when the first submarine fan model was launched by Arnold Bouma in 1962? Since that date students of submarine fans have worked on a number of important, recurring questions concerned with facies analysis of submarine successions in outcrop and core: 1. What type of sediment transport produced the beds? 2. What facies can be related to initial flow conditions? 3. What is the significance of grain size jumps and bounding surface hierarchy in beds consisting of crude and spaced stratification (traction carpets)? Do these point to multi flow events or to flow pulsations by one and the same event? 4. What facies associations relate to the basic elements of submarine fans? 5. What are the autogenic and allogenic signatures in submarine fans? Particularly in the last decade, the enormous technical advancement helped to obtain high-quality data from observations of density flows in modern canyons, deep basins and deep-water delta slopes (refs 1,2,3). In combination with both physical (refs 4,5) and numerical modelling (ref 6) these studies broke new ground into our understanding of density flow processes in various submarine environments and have led to new concepts of submarine fan building by super- and subcritical high-density flow (ref 7). Do these new concepts provide better answers to our recurrent questions related to the morphodynamics of submarine fans and prediction of sand body architecture? In discussing this open question, I shall 1. apply the new concepts to a modern and ancient example of a channel-lobe-transition-zone (ref 8); 2. raise the problem of

  2. Miocene Current-Modified Submarine Fans

    Science.gov (United States)

    Arce Perez, L. E.; Snedden, J.; Fisher, W. L.

    2016-12-01

    In the southwestern Gulf of Mexico, new and newly reprocessed seismic data has revealed a series of large bedforms, with set thicknesses of 130 to 250 meters. These exhibit hummocky, oblique and shingled to parallel seismic clinoform reflections. This seismic package has a paleowater depth of 450 meters. Those shingled seismic reflections in offshore east Mexico are interpreted as contourite drift deposits. These Miocene-age contourites may be related to strong ocean bottom currents that modified submarine fans and transported sediment to the north. Those contourites were identified on older seismic data, but are better imaged and interpreted on this new data. Plans are to map out and investigate the origin and extent of fans and contourites that extends over a large area of the Gulf of Mexico. In the Early Miocene several submarine fans systems were formed by the sediment input related to orogenic activity in Mexico. Submarine fan development persisted into the Middle Miocene due to continued uplift and erosion of the Mexican landmass. Initial, contourites are small and close proximity to the deep-water fan. In the Late Miocene time, contourite drift field reached its maximum extent in the Mexican deepwater area, anchored on its southern end by a submarine mound. This mounded submarine fan is located in the offshore northeast Veracruz and can be linked to increased uplift and erosion of the Trans-Mexican volcanic belt. In the Miocene-Pliocene, the large contourite drift begins to diminish in size and scale and is moribund by the Pliocene, with establishment of oceanic circulation similar to the present day. This research is important to understand more about the Gulf of Mexico and also for the Miocene timeframe that is a key phase in the earth's history. The role of the change in bottom water flow during progressive closure of the equatorial seaway separating North and South America will also be investigated.

  3. Submarine fans: A critical retrospective (1950–2015

    Directory of Open Access Journals (Sweden)

    G. Shanmugam

    2016-04-01

    Full Text Available When we look back the contributions on submarine fans during the past 65 years (1950–2015, the empirical data on 21 modern submarine fans and 10 ancient deep-water systems, published by the results of the First COMFAN (Committee on FANs Meeting (Bouma et al., 1985a, have remained the single most significant compilation of data on submarine fans. The 1970s were the “heyday” of submarine fan models. In the 21st century, the general focus has shifted from submarine fans to submarine mass movements, internal waves and tides, and contourites. The purpose of this review is to illustrate the complexity of issues surrounding the origin and classification of submarine fans. The principal elements of submarine fans, composed of canyons, channels, and lobes, are discussed using nine modern case studies from the Mediterranean Sea, the Equatorial Atlantic, the Gulf of Mexico, the North Pacific, the NE Indian Ocean (Bay of Bengal, and the East Sea (Korea. The Annot Sandstone (Eocene–Oligocene, exposed at Peira-Cava area, SE France, which served as the type locality for the “Bouma Sequence”, was reexamined. The field details are documented in questioning the validity of the model, which was the basis for the turbidite-fan link. The 29 fan-related models that are of conceptual significance, developed during the period 1970–2015, are discussed using modern and ancient systems. They are: (1 the classic submarine fan model with attached lobes, (2 the detached-lobe model, (3 the channel-levee complex without lobes, (4 the delta-fed ramp model, (5 the gully-lobe model, (6 the suprafan lobe model, (7 the depositional lobe model, (8 the fan lobe model, (9 the ponded lobe model, (10 the nine models based on grain size and sediment source, (11 the four fan models based on tectonic settings, (12 the Jackfork debrite model, (13 the basin-floor fan model, (14 supercritical and subcritical fans, and (15 the three types of fan reservoirs. Each model is unique

  4. Calciclastic submarine fans: An integrated overview

    Science.gov (United States)

    Payros, Aitor; Pujalte, Victoriano

    2008-01-01

    Calciclastic submarine fans are rare in the stratigraphic record and no bona fide present-day analogue has been described to date. Possibly because of that, and although calciclastic submarine fans have long intrigued deep-water carbonate sedimentologists, they have largely been overlooked by the academic and industrial communities. To fill this gap we have compiled and critically reviewed the existing sedimentological literature on calciclastic submarine fans, thus offering an updated view of this type of carbonate slope sedimentary system. Calciclastic submarine fans range in length from just a few to more than 100 km. Three different types can be distinguished: (1) Coarse-grained, small-sized (depression associated with tectonic structures, an inherited topography, or large-scale mass failures.

  5. A submarine fan in the Mesa Central, Mexico

    Science.gov (United States)

    Silva-Romo, G.; Arellano-Gil, J.; Mendoza-Rosales, C.; Nieto-Obregón, J.

    2000-10-01

    The contact between the Guerrero and Sierra Madre tectonostratigraphic terranes has been proposed to lie in the Mesa Central, east of the city of Zacatecas. Marine Triassic units have been assigned to the Guerrero Terrane. It is here proposed that this contact occurs to the west of the city of Zacatecas and the Triassic marine sequence assigned to the Sierra Madre Terrane. We analyzed the stratigraphic record and structural features of pre-Late Jurassic sequences at four localities in the Mesa Central. They contain a marine turbiditic Triassic unit, which includes La Bellena, Taray, and Zacatecas Formations, and a continental unit of probable Middle Jurassic age. Triassic sandstones were derived from a cratonic area, without the influence of arc volcanism. The sequences were affected by two phases of deformation. The Triassic formations are unconformably overlain by a continental volcano-sedimentary sequence that contains fragments of sandstones derived from the underlying unit. Sedimentologic characteristics of the Triassic unit fit a submarine fan model. The submarine fan developed at the continental margin of Pangaea during Triassic times. Turbidite associations in the San Rafael Area indicate a middle fan depositional environment, while in the Real de Catorce Area, they correspond to the distal part (basin plain facies). At La Ballena and Zacatecas the turbidite associations occur in the middle part and perhaps the external part of the fan.

  6. Rapid shut-off and burial of slope channel-levee systems: new imaging and analysis of the Rio Grande submarine fan

    Science.gov (United States)

    Swartz, J. M.; Mohrig, D. C.; Gulick, S. P. S.; Stockli, D. F.; Daniller-Varghese, M. S.; Fernandez, R.

    2016-12-01

    The continental slope of the western Gulf of Mexico is host to a major depositional system, the Rio Grande Fan. Unlike many submarine fans, the surface of the Rio Grande Fan lacks large submarine channels and associated levees. Prior analysis of continental shelf stratigraphy has identified the presence of past extensive shelf-edge delta systems, when the Rio Grande River system flowed across the modern shelf and delivered high volumes of sediment to the shelf/slope break. A major gap in understanding this system is how large volumes of sediment, particularly sands, are transported from the shelf edge systems down the slope and onto the basin-floor fan without constructional channel-levee systems. Over 500km of new high-resolution 2D multichannel seismic (MCS) and CHIRP echosounder data were collected over the shelf edge and upper slope of the Rio Grande fan. These new data provide unprecedented imaging of the shelf-edge delta systems and associated slope deposits. Our preliminary observations indicate that while the modern seafloor morphology of the fan is dominated by mass-transport deposits, slumps and minor inactive channels, buried below thick mud deposits are very large aggradational channels-levee systems. These systems have channel belts almost 1km wide, with confining levees that approach 10km in width. The main body of the fan is built from these channel complexes, which appear to have then rapidly buried in mud. We document the evolution, from initial channelization to burial, of these massive slope systems. Regional correlation suggests that this most recent episode of channel-levee growth and shutoff occurred very rapidly, and could indicate drastically higher sediment flux through the paleo-Rio Grande River than that of the modern. Our results highlight an example of a slope-channel system that is subject to significant variations in sediment supply. Such systems can apparently build large late Pleistocene submarine fan deposits that can be difficult

  7. Late Cretaceous Sub-Marine Fan System in Batain Mélange Zone, the Fayah Formation in Northeastern Oman

    Directory of Open Access Journals (Sweden)

    Iftikhar Ahmed Abbasi

    2014-06-01

    , possibly as olistostrome formed due to submarine slumping and sliding. The turbidite lithofacies association is comprised of monotonous grayish-green to brown coloured clays tens of meters thick interbedded with thin, clean, well-sorted sandstone. The Interbedded sandstone and shale lithofacies association is comprised of a half to one meter thick cross-bedded, burrowed arkosic sandstone and plane laminated shale. The sandstone constitutes about 25% of the association with ripple lamination in the upper part of the unit indicating a fining-upward trend. Dewatering structures are common. This association constitutes the upper 100m of the formation. These sediments were deposited in shallow water conditions by channelized flows. Based on the lithofacies associations described above, especially the dominance of debris-flow units and turbidites, the greater part of the Fayah Formation are interpreted as having been deposited under a sub-marine fan setting. Only the upper part of the formation was deposited in a shallow water setting before the onset of overlying carbonate deposits. The sub-marine fan system was active during the last stages of the Tethys Ocean closure at the time of onset of the Batain nappe.

  8. Mozambique upper fan: origin of depositional units

    Energy Technology Data Exchange (ETDEWEB)

    Droz, L.; Mougenot, D.

    1987-11-01

    The upper Mozambique Fan includes a stable down-stream region, with a north-south channel flanked by thick (1.5 sec two-way traveltime) asymmetric levees, and a migrating upstream region where at least two main feeding paths have been successively dominant. From the Oligocene to early Miocene, the north-south Serpa Pinto Valley acted as the main conduit for the north Mozambique terrigenous sediments. From the middle Miocene, the west-east Zambezi Valley became the dominant path and supplied the fan with sediments transported by the Zambezi River from the central part of Mozanbique. The transfer from one sediment-feeding system to the other is related to the abandonment of the Serpa Pinto Valley because of graben formation along the Davie Ridge, which trapped the sediments, and the increase of the Zambezi River sediment supply because of the creation and erosion of the East African Rift. 13 figures.

  9. Autogenic influence on the morphology of submarine fans: an approach from 3D physical modelling of turbidity currents

    Directory of Open Access Journals (Sweden)

    Cristiano Fick

    Full Text Available ABSTRACT: Autogenic controls have significant influence on deep-water fans and depositional lobes morphology. In this work, we aim to investigate autogenic controls on the topography and geometry of deep-water fans. The influence of the sediment concentration of turbidity currents on deep-water fans morphology was also investigated. From the repeatability of 3D physical modeling of turbidity currents, two series of ten experiments were made, one of high-density turbidity currents (HDTC and another of low-density turbidity currents (LDTC. All other input parameters (discharge, sediment volumetric concentration and grain size median were kept constant. Each deposit was analyzed from qualitative and quantitative approaches and statistical analysis. In each experimental series, the variability of the morphological parameters (length, width, L/W ratio, centroid, area, topography of the simulated deep-water fans was observed. Depositional evolution of the HDTC fans was more complex, showing four evolutionary steps and characterized by the self-channelizing of the turbidity current, while LDTC fans neither present self-channelizing, nor evolutionary steps. High disparities on the geometrical parameters of the fans, as characterized by the elevated relative standard deviation, suggest that autogenic controls induced a stochastic morphological behaviour on the simulated fans of the two experimental series.

  10. Submarine pyroclastic deposits in Tertiary basins, NE Slovenia

    Directory of Open Access Journals (Sweden)

    Polona Kralj

    2013-12-01

    Full Text Available In Tertiary basins of NE Slovenia, Upper Oligocene volcanic activity occurred in a submarine environment that experienced contemporaneous clastic sedimentation. Pyroclastic deposits are essentially related to gas- and watersupported eruption-fed density currents. At Trobni Dol, the Lako Basin, an over 100 m thick deposit formed by a sigle sustained volcanic explosion that fed gas-supported pyroclastic flow. Diagnostic features are large matrixshard content, normal grading of pumice lapilli, collapsed pumice lapilli and the presence of charcoal. In the Smrekovec Volcanic Complex, several but only up to 5 m thick deposits related to eruption-fed gassupported pyroclastic flows occur. Deposits settled from water-supported eruption-fed density currents form fining- and thinning-upward sedimentary units which resemble the units of volcaniclastic turbidites. Pyroclastic deposits related to gas- and water-supported density currents occur in an up to 1000 m thick succession composed of coherent volcanics, autoclastic, pyroclastic, reworked volcaniclastic and mixed volcaniclastic-siliciclastic deposits that indicate a complex explosive and depositional history of the Smrekovec Volcanic Complex.

  11. Carbonate cements and grains in submarine fan sandstones—the Cergowa Beds (Oligocene, Carpathians of Poland) recorded by cathodoluminescence

    Science.gov (United States)

    Pszonka, Joanna; Wendorff, Marek

    2017-01-01

    The cathodoluminescence (CL) observations with cold cathode, supplemented by reconnaissance scanning electron microscope analyses, bring new data on petrology, provenance and diagenesis of the Oligocene-age Cergowa sandstones from the Outer Carpathians (SE Poland). The sandstones represent a variety of mass gravity flow sediments deposited on a submarine fan, which now forms a lenticular lithosome—a part of the Menilite Beds-Krosno Beds suite important for the hydrocarbons industry. The most common components of the Cergowa sandstones observed under the CL are carbonates—cement and grains that are mainly represented by lithoclasts. Carbonate cement is represented by five generations: brown (Cb), orange (Co), yellow (Cy), zoned (Cz) and black (Ck). Pore-filling Cb and Co calcite cements are interpreted as genetically related to eo- and mesodiagenetic phases. The mesodiagenetic phase is characterised by randomly distributed relatively large monocrystalline-zoned rhombs of dolomite cement (Cz) and ankerite/ferroan dolomite (Ck). The telodiagenetic phase is represented by pore-filling yellow calcite (Cy) that crystallised under the influence of suboxic meteoric waters. Lithoclasts represent six microfacies of carbonate rocks eroded in the source area, i.e. microbreccia, tectonised immature calcarenite/wacke, microsparite, sparite, biomicrosparite/packstone and dolostone. Pronounced indentations of terrigenous sand grains into intraclasts of packstone/biomicrosparite, coupled with commonly present similar packstone-type matrix, suggest that a significant part of matrix resulted from compaction of soft biomicrosparite grains. Terrigenous grains bound by calcite cement are commonly corroded by acidic diagenetic fluids, and partial or even complete replacement of silicates by calcite and clay minerals is illustrated here by feldspar grains. Substantial carbonate cementation has resulted in both the significant hardness and abrasion resistance of the Cergowa sandstones

  12. Research on the architecture of submarine-fan lobes in the Niger Delta Basin, offshore West Africa

    Directory of Open Access Journals (Sweden)

    Jia-Jia Zhang

    2016-07-01

    Results show that (1 A lobe complex was composed of multiple individual lobes as the compensational stacking pattern. According to the stacked relationship among individual lobes, four types of compensational stacking pattern were classified as the inordered type, the lateral migration type, the retrograding type and the prograding type. Influenced by the laterally confined degree of palaeotopography, the basin floor fan lobe complex was easily superimposed as inordered type, showing relatively large lateral width but relatively small thickness; the slope fan lobe complex was easily superimposed as lateral migration, retrograding and prograding types, showing relatively small lateral width but relatively large thickness. (2 Influenced by the laterally confined degree of palaeotopography, the basin floor fan individual lobes showed relatively large planar distribution area but relatively small thickness, while the slope fan individual lobes showed relatively small planar distribution area but relatively large thickness. An individual lobe was composed of multiple lobe stories by the way of aggradation–progradation pattern. From proximal to middle and distal part of individual lobes, the bottom mass-transport-deposits and the top branch channels disappeared gradually, and the amalgamated degree of the middle tabular sandbodies weakened as well with gradually developing of muddy interlayers. The formation of an individual lobe generally includes three stages as “rapid accumulation–progradation–aggradation”.

  13. Improved recovery from Gulf of Mexico reservoirs. Volume I (of 4): Task 1, conduct research on mud-rich submarine fans. Final report, February 14, 1995--October 13, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Kimbrell, W.C.; Bassiouni, Z.A.; Bourgoyne, A.T.

    1997-01-13

    The objective for this portion of the research involved conducting field studies and laboratory investigations to develop and refine models for mud-rich submarine fan architectures used by seismic analysis and reservoir engineers. These research aspects have been presented in two papers as follows: (1) Bouma, A.H., {open_quotes}Review of Fine-Grained Submarine Fans and Turbidite Systems{close_quotes}; (2) Kirkova, J.T. and Lorenzo, J.M., {open_quotes}Synthetic Seismic Modeling of Measured Submarine Fans Sections, Case Study of the Tanqua Complex, Karoo, South Africa{close_quotes} The {open_quotes}Review of Fine-Grained Submarine Fans and Turbidite Systems{close_quotes} by Arnold Bouma discusses research targeted toward stimulating an increase in oil and gas recovery by developing new and improved geological understanding. The {open_quotes}Synthetic Seismic Modeling of Measured Submarine Fan Sections, Case Study of the Tanqua Complex, Karoo, South Africa{close_quotes} by J.T. Kirkova and J.M. Lorenso discusses the limitations of verticle resolution and how this affects the interpretation and characterization of submarine fan complexes.

  14. Estimation of submarine mass failure probability from a sequence of deposits with age dates

    Science.gov (United States)

    Geist, Eric L.; Chaytor, Jason D.; Parsons, Thomas E.; ten Brink, Uri S.

    2013-01-01

    The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from renewal process theory and Monte Carlo methods. The estimated mean return time from these methods, unlike estimates from a simple arithmetic mean of the center age dates and standard likelihood methods, includes the effects of age-dating uncertainty and of open time intervals before the first and after the last event. The likelihood techniques are evaluated using Akaike’s Information Criterion (AIC) and Akaike’s Bayesian Information Criterion (ABIC) to select the optimal model. The techniques are applied to mass transport deposits recorded in two Integrated Ocean Drilling Program (IODP) drill sites located in the Ursa Basin, northern Gulf of Mexico. Dates of the deposits were constrained by regional bio- and magnetostratigraphy from a previous study. Results of the analysis indicate that submarine mass failures in this location occur primarily according to a Poisson process in which failures are independent and return times follow an exponential distribution. However, some of the model results suggest that submarine mass failures may occur quasiperiodically at one of the sites (U1324). The suite of techniques described in this study provides quantitative probability estimates of submarine mass failure occurrence, for any number of deposits and age uncertainty distributions.

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

    Science.gov (United States)

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

    2007-11-22

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

  16. Depositional processes of alluvial fans along the Hilina Pali fault scarp, Island of Hawaii

    Science.gov (United States)

    Morgan, Alexander M.; Craddock, Robert A.

    2017-11-01

    A series of previously unstudied alluvial fans are actively forming along the Hilina Pali escarpment on the south flank of Kīlauea volcano on the Island of Hawaii. These fans are characterized by their steep slopes, coarse grain sizes, and lobate surface morphology. Fans are fed by bedrock channels that drain from the Ka'ū Desert, but sediment is mostly sourced from deeply eroded alcoves carved into the Hilina Pali. Examination of recent deposits indicates that the fans are dominantly constructed from gravel and larger sized sediment. Flow discharges calculated using field measurements of channel geometries and the Manning equation indicate that events inducing sediment transport are of high magnitude and occur during high intensity precipitation events, including Kona storms. The fans along the Hilina Pali appear to be a rare example of fans formed predominately from sieve lobe deposition owing to the area's high slopes, high discharge, coarse bedload, and limited supply of fine-grained sediment. Given such conditions, sieve lobe deposition can form large lobes consisting of boulder-sized material, which may have implications for the identification of depositional processes when interpreting the stratigraphic record.

  17. ESR dating of submarine hydrothermal activities using barite in sulfide deposition

    Science.gov (United States)

    Toyoda, S.; Fujiwara, T.; Ishibashi, J.; Isono, Y.; Uchida, A.; Takamasa, A.; Nakai, S.

    2012-12-01

    The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation (Urabe, 1995) and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). Determining the ages of the hydrothermal deposit will provide essential information on such studies. Dating methods using disequilibrium between radioisotopes such as U-Th method (e.g. You and Bickle, 1998), 226}Ra-{210Pb and 228}Ra-{228Th method (e.g. Noguchi et al., 2011) have been applied to date submarine hydrothermal deposits. ESR (electron spin resonance) dating method is commonly applied to fossil teeth, shells, and quartz of Quaternay period where the natural accumulated dose is obtained from the intensities of the ESR signals which are created by natural radiation. The natural dose is divided by the dose rate to the mineral/sample to deduce the age. Okumura et al., (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite (BaSO4) to obtain preliminary ages, where Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. Knowing that ESR dating of barite is promising, in this paper, we will present how we have investigated each factor that contributes ESR dating of barite in submarine hydrothermal sulfide deposition. (1) The best ESR condition for measuring the SO3- signal in barite is with the microwave power of 1mW and modulation amplitude of 0.1mT. (2) As results of heating experiments, the signal was found to be stable for the dating age range of several thousands. (3) 226Ra replacing Ba in barite is the source of the radiation. The amount of radioactive elements in sulfide mineral surrounding barite is negligible. (4) The external radiation from the sea water is negligible even in the submarine hydrothermal area where the radiation level is much

  18. Calculations of turbidite deposits and tsunamis from submarine landslides

    Energy Technology Data Exchange (ETDEWEB)

    Gisler, Galen R [Los Alamos National Laboratory; Weaver, Robert P [Los Alamos National Laboratory; Gittings, Michael L [Los Alamos National Laboratory

    2009-01-01

    Great underwater landslides like Storegga off the Norwegian coast leave massive deposits on the seafloor and must produce enormous tsunamis. Such events have occurred on continental slopes worldwide, and continue to do so. Triggers for such slides include earthquakes, gas hydrate releases, and underwater volcanos. We have petformed a numerical study of such landslides using the multi-material compressible hydrocode Sage in order to understand the relationship between the rheology of the slide material, the configuration of the resulting deposits on the seafloor, and the tsunami that is produced. Instabilities in the fluid-fluid mixing between slide material and seawater produce vortices and swirls with sizes that depend on the rheology of the slide material. These dynamical features of the flow may be preserved as ridges when the sliding material finally stops. Thus studying the configuration of the ridges in prehistoric slides may give us measures of the circumstances under which the slide was initiated. As part of this study, we have also done a convergence test showing that the slide velocity is sensitive to the resolution adopted in the simulation, but that extrapolation to infinite resolution is possible, and can yield good velocities. We will present two-dimensional simulations of schematic underwater slides for our study of rheology, and a three-dimensional simulation in bathymetric conditions that resemble the pre-Storegga Norwegian margin.

  19. Depositional architecture of fan deposits and preserved bedforms on the southwest margin of Mt. Sharp from HiRISE imagery

    Science.gov (United States)

    Ewing, R. C.; Milliken, R.; Fischer, W. W.; Hurowitz, J.; Team, M.

    2013-12-01

    A well-preserved fan complex flanks the southeastern side of the prominent ridge on the southwest side of Mt. Sharp and provides a key opportunity to examine the geomorphology and stratigraphy of a water-lain deposit on Mt. Sharp and expand the basin-scale, geological context for Curiosity rover. We used HiRISE imagery to map relationships between the complex and adjacent strata, which sit at a slope break at the base of Mt. Sharp and contain linear dune-scale bedforms. Detailed mapping of the five by one kilometer complex reveals three inverted trunk channels that feed three to five fans composed of inverted distributary channels, which, as a complex, appear deflected toward the southwest. Two depositional facies define the proximal to distal transition of the complex onto the adjacent plain. The braided distributary channels display low sinuosity ranging from 1.1 to 1.4 and, based upon mapping of well-exposed channel walls, are composed of alternating light and dark toned bedding with internal, inclined stratification. The distributary channels sit above and terminate abruptly at an unchanneled, thinly-bedded, highly-fractured unit, which extends to the distal reaches of the fan complex and overlies a field of preserved, lithified, dune-scale bedforms that floors the adjacent plains. The straight-crested bedforms are regularly spaced around fifty meters, show bifurcations typical of defect interactions occurring with bedform migration, and terminate abruptly at the contact with the overlying fractured unit. The fans record fluvial incision of the Lower formation of Mt. Sharp and are distinct from the underlying bedforms, which we interpret to be aeolian in origin. Deflection of the fan complex to the southwest may relate to deposition onto a local southwest dipping slope of the plain and the proximal-to-distal transition in facies likely reflects a grain-size transition associated with waning energy across the system. Inclined stratification within the

  20. Submarine Slope Failure Primed and Triggered by Bottom Water Warming in Oceanic Hydrate-Bearing Deposits

    Directory of Open Access Journals (Sweden)

    Tae-Hyuk Kwon

    2012-08-01

    Full Text Available Many submarine slope failures in hydrate-bearing sedimentary deposits might be directly triggered, or at least primed, by gas hydrate dissociation. It has been reported that during the past 55 years (1955–2010 the 0–2000 m layer of oceans worldwide has been warmed by 0.09 °C because of global warming. This raises the following scientific concern: if warming of the bottom water of deep oceans continues, it would dissociate natural gas hydrates and could eventually trigger massive slope failures. The present study explored the submarine slope instability of oceanic gas hydrate-bearing deposits subjected to bottom water warming. One-dimensional coupled thermal-hydraulic-mechanical (T-H-M finite difference analyses were performed to capture the underlying physical processes initiated by bottom water warming, which includes thermal conduction through sediments, thermal dissociation of gas hydrates, excess pore pressure generation, pressure diffusion, and hydrate dissociation against depressurization. The temperature rise at the seafloor due to bottom water warming is found to create an excess pore pressure that is sufficiently large to reduce the stability of a slope in some cases. Parametric study results suggest that a slope becomes more susceptible to failure with increases in thermal diffusivity and hydrate saturation and decreases in pressure diffusivity, gas saturation, and water depth. Bottom water warming can be further explored to gain a better understanding of the past methane hydrate destabilization events on Earth, assuming that more reliable geological data is available.

  1. Depositional environment of a fan delta in a Vistulian proglacial lake (Skaliska Basin, north-eastern Poland

    Directory of Open Access Journals (Sweden)

    Woronko Barbara

    2013-06-01

    Full Text Available The study reconstructed the environment of a fan delta filling the vast end depression of the Skaliska Basin, and its overlying aeolian deposits. The formation of the large fan delta is associated with the presence of an ice-dammed lake functioning during the retreat of the Vistulian Glaciation (MIS 2. The examined material was collected from five boreholes. Sediments were analysed for their granulometric composition and subjected to analyses of frosting and rounding of quartz grains. Grain size analysis showed that the fan delta deposits are built of sand sediments of very low lateral and vertical variability. The fan delta was supplied with fluvioglacial sediments. Accumulation of sediments occurred in shallow water with a very low-gradient slope. The exposed fan delta became a site conducive to aeolian processes after the lake waters fell and the Skaliska Basin depression dried. Dune deposits overlying the fan were affected by short-distance transport so they did not acquire features typical for aeolian deposits.

  2. Development of the Astoria Canyon-Fan physiography and comparison with similar systems

    Science.gov (United States)

    Nelson, C.H.; Carlson, P.R.; Byrne, J.V.; Alpha, T.R.

    1970-01-01

    A detailed bathymetric study of Astoria Canyon and Astoria Fan provides a model for typical submarine canyon-fan systems. The present canyon head is 9 miles (17 km) west of the Columbia River mouth but buried Pleistocene channels appear to have connected the two features in the past. The canyon, which is distinguished by its relief, V-shaped profiles, and numerous tributaries, winds sinuously and is coincident with apparent structural trends across the continental shelf and slope. At the fan apex, the canyon mouth merges smoothly into Astoria Channel, which is characterized by its U-shaped profiles, lower walls of even height, and levee development. Astoria Channel and the fan valley at the base of the continental slope are the most recently active of a series of main fan valleys that appear to have: (1) progressively "hooked left"; (2) migrated from north to south across the fan during its formation; and (3) been partly responsible for the asymmetrical shape of the fan. The deep, narrow upper fan valleys that characterize the steep (> 1:100, or 0??35???) and rough (10-30 fathoms, or 18-55 m) upper fan surface break into distributaries on the middle fan, where there is the sharpest change in gradient. The main valleys become broader and shallower down the fan, while the generally concave fan surface grades to nearly a flat seafloor (to gradients Similarity of Astoria Canyon-Fan system with other deep-sea fan and alluvial fan systems, suggests the hypothesis that size of drainage basin, sediment size, and sediment load control the size, gradient, and valley development of any fan system. Data from bathymetry, seismic refraction stations, and sediment load of the Columbia River indicate that the cutting of Astoria Canyon and the deposition of the unconsolidated sediment layer forming Astoria Fan could have been accomplished during the Pleistocene. A similar history can be suggested for other major submarine canyon-fan systems. ?? 1970.

  3. Glacial-interglacial climate changes recorded by debris flow fan deposits, Owens Valley, California

    Science.gov (United States)

    D'Arcy, Mitch; Roda-Boluda, Duna C.; Whittaker, Alexander C.

    2017-08-01

    It is hotly debated whether and how climate changes are recorded by terrestrial stratigraphy. Basin sediments produced by catchment-alluvial fan systems may record past climate over a variety of timescales, and could offer unique information about how climate controls sedimentation. Unfortunately, there are fundamental uncertainties about how climatic variables such as rainfall and temperature translate into sedimentological signals. Here, we examine 35 debris flow fan surfaces in Owens Valley, California, that record deposition throughout the past 125,000 years, during which climate has varied significantly. We show that the last full glacial-interglacial cycle is recorded with high fidelity by the grain size distributions of the debris flow deposits. These flows transported finer sediment during the cooler glacial climate, and became systematically coarser-grained as the climate warmed and dried. We explore the physical mechanisms that might explain this signal, and rule out changes in sediment supply through time. Instead, we propose that grain size records past changes in storm intensity, which is responsible for debris flow initiation in this area and is decoupled from average rainfall rates. This is supported by an exponential Clausius-Clapeyron-style scaling between grain size and temperature, and also reconciles with climate dynamics and the initiation of debris flows. The fact that these alluvial fans exhibit a strong, sustained sensitivity to orbital climate changes sheds new light on how eroding landscapes and their sedimentary products respond to climatic forcing. Finally, our findings highlight the importance of threshold-controlled events, such as storms and debris flows, in driving erosion and sedimentation at the Earth's surface in response to climate change.

  4. Successive, large mass-transport deposits in the south Kermadec fore-arc basin, New Zealand: The Matakaoa Submarine Instability Complex

    National Research Council Canada - National Science Library

    Geoffroy Lamarche; Cathy Joanne; Jean-Yves Collot

    2008-01-01

    Four >100 km3 mass-transport deposits (MTDs) identified from their morphology and seismic facies across the Matakaoa Margin and Raukumara fore-arc basin, NE New Zealand, constitute the Matakaoa Submarine Instability Complex (MSIC...

  5. Sedimentological evidence for a deltaic origin of the western fan deposit in Jezero crater, Mars and implications for future exploration

    Science.gov (United States)

    Goudge, Timothy A.; Milliken, Ralph E.; Head, James W.; Mustard, John F.; Fassett, Caleb I.

    2017-01-01

    We examine the stratigraphic architecture and mineralogy of the western fan deposit in the Jezero crater paleolake on Mars to reassess whether this fan formed as a delta in a standing body of water, as opposed to by alluvial or debris flow processes. Analysis of topography and images reveals that the stratigraphically lowest layers within the fan have shallow dips (confidently distinguish between alluvial fans and deltas. Our results indicate that Jezero crater contains exceptionally well-preserved fluvio-deltaic stratigraphy, including strata interpreted as fine-grained deltaic bottomsets that would have had a high potential to concentrate and preserve organic matter. Future exploration of this site is both geologically and astrobiologically compelling, and in situ analyses would be complementary to the ongoing in situ characterization of fluvio-lacustrine sediment in the Gale crater paleolake basin by the Curiosity rover.

  6. Lacustrine fan delta deposition alongside intrabasinal structural highs in rift basins: an example from the Early Cretaceous Jiuquan Basin, Northwestern China

    Science.gov (United States)

    Zhang, Chengcheng; Muirhead, James D.; Wang, Hua; Chen, Si; Liao, Yuantao; Lu, Zongsheng; Wei, Jun

    2018-01-01

    Development of fan deltas alongside intrabasinal structural highs has been overlooked compared to those forming on basin margins. However, these fan deltas may provide important clues regarding the tectonic and climatic controls on deposition during rift development. This paper documents fan delta deposition alongside an intrabasinal structural high within the Early Cretaceous Xiagou Formation of the Jiuquan Basin, China, using subsurface geological and geophysical data. Deposits observed in drill core support fan delta deposition occurring almost exclusively through subaerial and subaqueous gravity flows. Subsurface mapping reveals a consistent decrease in the areal extent of fan deltas from lowstand to highstand system tracts, suggesting that deposition alongside the structural high is sensitive to lake-level changes. The temporal and spatial distribution of the fan deltas display retrogradational stacking patterns, where fan deltas exhibit a decreasing lateral extent up-sequence until fan delta deposition terminated and was replaced by deposition of fine-grained lacustrine deposits. The retrogradational stacking patterns observed alongside the intrabasinal structural high are not observed in fan deltas along the basin margin in the lower parts of the Xiagou Formation. Subsidence profiles also show differential subsidence across the basin during the earliest stages of this formation, likely resulting from border fault movements. These data suggest that non-uniform stacking patterns in the lower parts of the Xiagou Formation reflect basin-scale tectonic movements as the dominant control on synrift deposition patterns. However, later stages of Xiagou Formation deposition were characterized by uniform subsidence across the basin, and uniform retrogradational stacking patterns for fan deltas alongside the intrabasinal structural high and border fault. These observations suggest that basin-scale tectonic movements played a relatively limited role in controlling

  7. Shale tectonics and structural deformation on the Amazon submarine fan: preliminaries results; Processo de argilocinese e estruturacao do pacote sedimentar da regiao do leque submarino do Amazonas: resultados preliminares

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Valterlene de; Silva, Cleverson Guizan [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Geociencias. Lab. de Geologia Marinha (LAGEMAR); Reis, Antonio Tadeu dos [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Dept. de Oceanografia

    2004-07-01

    The Amazon Submarine Fan, part of the Amazon Mouth Basin, is strongly affected by shale tectonics. Preliminary analysis of about 9.000 Km of multichannel seismic lines allowed us to map three main structural domains: a proximal extensive province largely dominated by seaward-dipping listric normal faults soling into a decollement level (mobile shale, Neomiocene in age) and associated rollovers; an intermediate rigid gliding province, and a lowermost compressive front, dominated by thrust faults. An important point about gravity tectonics in this area is that the morphology of the base of the mobile level seems to have influenced the development of the structural styles. For instance, listric faults lying at the upslope limit of the extensional province are arranged along a step-like morphology of the decollement level. As well as that, we observed that the gradient of the decollement level is more important on the northwestern portion of the fan, where the distance between the extensive and the compressive province is larger (of about 40 Km) than on the southeastern portion of the fan (about 25 Km large). Then, on the basis of the basal level gradient and the structures disposition we can segment the fan area into two structural compartments: a northwest and a southeast compartment. (author)

  8. Gravitational, erosional and depositional processes on volcanic ocean islands: Insights from the submarine morphology of Madeira Archipelago

    Science.gov (United States)

    Quartau, Rui; Ramalho, Ricardo S.; Madeira, José; Santos, Rúben; Rodrigues, Aurora; Roque, Cristina; Carrara, Gabriela; Brum da Silveira, António

    2018-01-01

    The submarine flanks of volcanic ocean islands are shaped by a variety of physical processes. Whilst volcanic constructional processes are relatively well understood, the gravitational, erosional and depositional processes that lead to the establishment of large submarine tributary systems are still poorly comprehended. Until recently, few studies have offered a comprehensive source-to-sink approach, linking subaerial morphology with near-shore shelf, slope and far-field abyssal features. In particular, few studies have addressed how different aspects of the subaerial part of the system (island height, climate, volcanic activity, wave regime, etc.) may influence submarine flank morphologies. We use multibeam bathymetric and backscatter mosaics of an entire archipelago - Madeira - to investigate the development of their submarine flanks. Crucially, this dataset extends from the nearshore to the deep sea, allowing a solid correlation between submarine morphologies with the physical and geological setting of the islands. In this study we also established a comparison with other island settings, which allowed us to further explore the wider implications of the observations. The submarine flanks of the Madeira Archipelago are deeply dissected by large landslides, most of which also affected the subaerial edifices. Below the shelf break, landslide chutes extend downslope forming poorly defined depositional lobes. Around the islands, a large tributary system composed of gullies and channels has formed where no significant rocky/ridge outcrops are present. In Madeira Island these were likely generated by turbidity currents that originated as hyperpycnal flows, whilst on Porto Santo and Desertas their origin is attributed to storm-induced offshore sediment transport. At the lower part of the flanks (-3000 to -4300 m), where seafloor gradients decrease to 0.5°-3°, several scour and sediment wave fields are present, with the former normally occurring upslope of the latter

  9. Depositional Architecture of Late Pleistocene-Holocene Coastal Alluvial-fan System in the Coastal Range, Taiwan

    Science.gov (United States)

    Chen, S. T.; Chen, W. S.

    2016-12-01

    Since late Pleistocene, the Coastal Range (Philippine Sea plate) collided and overridden on the Central Range (Eurasian Plate) along the Longitudinal Valley Fault. Therefore, the Coastal Range is exposed widely the late Pleistocene-Holocene marine and fluvial terraces caused by the tectonic uplift. Based on the estimation of paleosea-level elevations (Δh), depositional paleodepth, altitude distribution of Holocene deposits (D), altitude of outcrops (H), and 14C dating of marine deposits (t), the uplift rate (=(Δh+H +d-D)/t) is about 5-10 mm/yr in the southern Coastal Range. In this study, we suggest through field logging that the deposits can be divided into alluvial, foreshore (intertidal), shoreface, and offshore environments. In Dulan area in the southern Coastal Range, the uplift rate was 6-7 mm/yr during 16,380-10,000 cal yr BP and 3-4 mm/yr after 7,000 cal yr BP. Results from the Dulan Coastal alluvial-fan system can be divided into five depositional stages: (1) 16,380-14,300 cal yr BP: The rate of global sea level rise (SLR) has averaged about 6-7 mm/yr, similar to the tectonic uplift rate. In this stage, the bedrock was eroded and formed a wide wave-cut platform. (2) 14,300-10,000 cal yr BP: SLR of about 14 mm/yr that was faster than tectonic uplift rate of 6-7 mm/yr. As a result of transgression, the beach-lagoon deposits about 5 m thick were unconformably overlain on the wave-cut platform. (3) 10,000-8,200 cal yr BP: The ongoing sea level rise (SLR: 11 mm/yr), the lagoon deposits were overlain by an offshore slump deposits representing a gradual deepening of the depositional environment. (4) 8,200-7,930 cal yr BP (SLR: 6-7 mm/yr): The tectonic uplift rate may occur at similar SLR. The alluvial-fan deposits have prograded over the shallow marine deposits. (5) After 7,000 cal yr BP (SLR: 1-0 mm/yr): SLR was much slower than tectonic uplift rate of 3-4 mm/yr. Thus, Holocene marine terraces are extensively developed in the coastal region, showing that the

  10. Multi-proxy geochemical analyses of Indus Submarine Fan sediments sampled by IODP Expedition 355: implications for sediment provenance and palaeoclimate reconstructions

    Science.gov (United States)

    Bratenkov, Sophia; George, Simon C.; Bendle, James; Liddy, Hannah; Clift, Peter D.; Pandey, Dhananjai K.; Kulhanek, Denise K.; Andò, Sergio; Tiwari, Manish; Khim, Boo-Keun; Griffith, Elizabeth; Steinke, Stephan; Suzuki, Kenta; Lee, Jongmin; Newton, Kate; Tripathi, Shubham; Expedition 355 Scientific Party

    2016-04-01

    The interplay between the development of the Asian summer monsoon and the growth of mountains in South and Central Asia is perhaps the most compelling example of the relationship between climate and the solid Earth. Understanding this relationship is crucial in the context of understanding past changes and for predicting future impacts in the Monsoon region. Both rapid and gradual mountain uplift influence the surrounding environments and regional climate. The sedimentary record of the Indus Fan offers a unique opportunity to study the climatic changes that occurred in South Asia and their link to the intensity of the erosion during the late Cenozoic. Although some paleoclimate reconstructions in the region can be partly addressed by studies onshore, the dominance of erosional processes in such a mountainous region ensures such records are fragmentary and limited in coverage. Thus ocean drilling is the best way to recover long sequences and to test the possible relations among mountain uplift, erosion, sediment deposition and climate (including carbon burial, chemical weathering and CO2 drawdown). The sediments and sedimentary rocks from the Indian continental margin, adjoining the Arabian Sea, were drilled during the International Ocean Discovery Program (IODP) Expedition 355. Drilling operations at Site U1456 penetrated through 1109.4 m of sediment and sedimentary rocks. The oldest sediment recovered at this site is dated to 13.5-17.7 Ma, with about 390 m of mass transport deposit. This study provides a multiproxy approach for palaeoenvironmental reconstructions in the Arabian Sea area. We use a wide variety of organic geochemical data coupled with inorganic chemistry, mineralogy, and isotopic analyses. For direct comparison among various data sets, we divided whole round residue from the interstitial water samples among different laboratories, with each receiving 50-300 g (dry mass). The preliminary results include initial sediment provenance data based on bulk

  11. Estimating gas escape through taliks in relict submarine permafrost and methane hydrate deposits under natural climate variation

    Science.gov (United States)

    Frederick, J. M.; Buffett, B. A.

    2013-12-01

    Permafrost-associated methane hydrate deposits exist at shallow depths within the sediments of the Arctic continental shelves. This icy carbon reservoir is thought to be a relict of cold glacial periods, when sea levels are much lower, and shelf sediments are exposed to freezing air temperatures. During interglacials, rising sea levels flood the shelf, bringing dramatic warming to the permafrost and gas hydrate bearing sediments. Degradation of this shallow-water reservoir has the potential to release large quantities of methane gas directly to the atmosphere. Although relict permafrost-associated gas hydrate deposits likely make up only a small fraction of the global hydrate inventory, they have received a disproportionate amount of attention recently because of their susceptibility to climate change. This study is motivated by several recent field studies which report elevated methane levels in Arctic coastal waters. While these observations are consistent with methane release as a result of decomposing submarine permafrost and gas hydrates, the source of gas cannot easily be distinguished from other possibilities, including the escape of deep thermogenic gas through permeable pathways such as faults, or microbial activity on thawing organic matter within the shelf sediments. In this study, we investigate the response of relict Arctic submarine permafrost and permafrost-associated gas hydrate deposits to warming with a two-dimensional, finite-volume model for two-phase flow of pore fluid and methane gas within Arctic shelf sediments. We track the evolution of temperature, salinity, and pressure fields with prescribed boundary conditions, and account for latent heat of water ice and methane hydrate formation during growth/decay of permafrost or methane hydrate. The permeability structure of the sediments is coupled to changes in permafrost. We assess the role of taliks (unfrozen portions of continuous permafrost) as a pathway for methane gas escape and make

  12. The modern Kaoping transient fan offshore SW Taiwan: Morphotectonics and development

    Science.gov (United States)

    Hsiung, Kan-Hsi; Yu, Ho-Shing; Chiang, Cheng-Shing

    2018-01-01

    Using bathymetry and seismic reflection profiles, this study examined and determined the transient nature of the Kaoping Fan located in the topographically complex slope offshore southwest Taiwan. Kaoping Fan is located west of the lower reach of the Kaoping Canyon at the lower Kaoping Slope, ranging from 2,200 to 3,000 m water depth, and has a relatively small areal extent restricted in the topographic lows confined by structural highs due to mud diapiric uplifting and thrust faulting. Kaoping Fan shows an asymmetrical triangular fan-shaped bathymetric feature elongated in an NW-SE direction but with a strong skew toward the east. The fan deposits consist of three main seismic facies: layered high-amplitude reflections in the upper section and stratified, parallel to sub-parallel low-amplitude reflections with variable continuity and channel fill facies in the lower section. In the absence of ground-truthing from core data, the seismic patterns suggest that the Kaoping Fan recorded the onset of channelized and over-bank deposits in the lower part and layered turbidite facies in the upper part subsequently. The development of the Kaoping Fan can be divided into three stages in terms of canyon activities and fan-feeding processes. Initially, Kaoping Fan was mainly fed by a point sediment source at the apex of the fan. Secondly, Kaoping Fan was maintained as a slope fan, mainly fed laterally by over-spilled sediments from the canyon. Finally, the Kaoping Canyon completely passes through the Kaoping Fan and supplies over-spilled sediments laterally, forming a transient fan with canyon incision and sediment by-passing. The accumulation of sediments and the growth of Kaoping Fan are primarily controlled by inherited complex paleo-topography and the evolution of Kaoping Canyon. The sediment delivery system of Kaoping Fan is characterized by lateral supply of over-spilling sediment flows and sediments bypassing to and beyond the base of slope. The Kaoping Fan together

  13. Paleomagnetic dating of tectonically influenced Plio-Quaternary fan-system deposits from the Apennines (Italy

    Directory of Open Access Journals (Sweden)

    Michele Saroli

    2015-03-01

    Full Text Available The Roveto Valley is a narrow, elongated, NW-trending depression filled with continental Plio-Quaternary deposits that outcrop at different topographic elevations. A morpho-lithostratigraphic succession of the continental deposits has been defined in order to reconstruct the geological Quaternary evolution of the area. These deposits do not contain materials suitable for biostratigraphic dating; therefore, in order to determine their chronology, three different units were sampled for magnetostratigraphic investigations. Paleomagnetic results demonstrated that standard demagnetization techniques are effective in removing secondary remanence components and in isolating the characteristic remanent magnetization, allowing us to determine, for each cycle, whether it was deposited before or after the Brunhes-Matuyama geomagnetic reversal at 781 ka. Preliminary rock magnetic analyses indicated that magnetite is the main magnetic carrier and that hematite, which gives the pink colour to the matrix, is in the superparamagnetic grain-size range and thus does not retain any paleomagnetic remanence.

  14. 3D architecture of cyclic-step and antidune deposits in glacigenic subaqueous fan and delta settings: Integrating outcrop and ground-penetrating radar data

    Science.gov (United States)

    Lang, Jörg; Sievers, Julian; Loewer, Markus; Igel, Jan; Winsemann, Jutta

    2017-12-01

    Bedforms related to supercritical flows are increasingly recognised as important constituents of many depositional environments, but outcrop studies are commonly hampered by long bedform wavelengths and complex three-dimensional geometries. We combined outcrop-based facies analysis with ground-penetrating radar (GPR) surveys to analyse the 3D facies architecture of subaqueous ice-contact fan and glacifluvial delta deposits. The studied sedimentary systems were deposited at the margins of the Middle Pleistocene Scandinavian ice sheets in Northern Germany. Glacifluvial Gilbert-type deltas are characterised by steeply dipping foreset beds, comprising cyclic-step deposits, which alternate with antidune deposits. Deposits of cyclic steps consist of lenticular scours infilled by backset cross-stratified pebbly sand and gravel. The GPR sections show that the scour fills form trains along the delta foresets, which can locally be traced for up to 15 m. Perpendicular and oblique to palaeoflow direction, these deposits appear as troughs with concentric or low-angle cross-stratified infills. Downflow transitions from scour fills into sheet-like low-angle cross-stratified or sinusoidally stratified pebbly sand, deposited by antidunes, are common. Cyclic steps and antidunes were deposited by sustained and surge-type supercritical density flows, which were related to hyperpycnal flows, triggered by major meltwater discharge or slope-failure events. Subaqueous ice-contact fan deposits include deposits of progradational scour fills, isolated hydraulic jumps, antidunes and (humpback) dunes. The gravel-rich fan succession consists of vertical stacks of laterally amalgamated pseudo-sheets, indicating deposition by pulses of waning supercritical flows under high aggradation rates. The GPR sections reveal the large-scale architecture of the sand-rich fan succession, which is characterised by lobe elements with basal erosional surfaces associated with scours filled with backsets related

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

    Science.gov (United States)

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

    2017-08-01

    Deep-sea fans are well known depot centers for organic carbon that should promote sulfate reduction. At the same time, the high rates of deposition of unconsolidated metal oxides from terrigenous origin may also promote metal-reducing microbial activity. To investigate the eventual coupling between the iron and sulfur cycles in these environments, shallow sediment cores (sulfur biogeochemical cycling in this environment is unique and much more similar to a coastal ecosystem than a deep-sea environment.

  16. Submarine landslides in Arctic sedimentation: Canada Basin

    Science.gov (United States)

    Mosher, David C.; Shimeld, John; Hutchinson, Deborah R.; Lebedova-Ivanova, N; Chapman, C.

    2016-01-01

    Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of development, Canada Basin is geomorphologically confined with stable oceanographic structure, resulting in restricted depositional/reworking processes. The sedimentary record, therefore, underscores the significance of mass-transport processes in providing sediments to oceanic abyssal plains as few other basins are able to do.

  17. Evolution Of Quaternary Stream Fan Deposits At The Confluences Of Turung Khola And Bembung Khola Of Middle Teesta Basin In Sikkim-Darjeeling Himalaya,India: A Tectonic - Climate Response

    Science.gov (United States)

    Lukram, I. M.

    2007-12-01

    Tributary fan deposits are well preserved on either side of the Teesta river in the non-glaciated middle part of the Himalayan valley lying in a tectonic region bounded by the MCT and MBT. The lithofacies characteristics and assemblage patterns of these deposits bear testimony to the effects of tectonic and climatic activities on the sedimentation process in the basin. Two tributary streams, with small catchments namely Turung Khola and Bembung Khola are important in this context. Three major fan lobes (F2, F1, and F0) are preserved at Turung Khola. In contrast, two fan lobes (F1,F0) are preserved at the confluence of the Bembung Khola. Terraces, floodplains, channel bars, chute bars are associated geomorphic features in this part of the Teesta basin. Landslides cover an area of 7% and 15% in the catchment of Turung Khola and Bembung Khola, respectively. Dense forest covers 24% and 12%; open forest covers 30% and 29 %; and scrubby vegetation covers 39% and 49% of the Turung Khola and Bembung Khola, respectively. The landslides mainly occur along the margins of the dense forest where they are active in every rainy season. Tributary longitudinal profiles and Hack profiles indicate a relationship between the knick points and high SL-Index values, where fault /thrust intersections are present. Active landslides and scarps are close to the major fault/thrust planes. Sediment characteristics of these fan deposits suggest that four types of depositional flows viz. debris flows, hyperconcentrated flows, sheet flows and channel flows laid down these sequences. The channel flow deposits are dominant (32%-54 %) in the fan sequence of the Turung Khola followed by sheet flow deposits (28.5%), hyperconcentrated flow deposits (26%) and debris flow deposits (12%), respectively. Hyperconcentrated flow deposits are dominant (44%) in the F1 sequence, whereas the active channel fanlobe is dominant (80%) in the channel flow deposits. The rest of the active channel sequence is composed

  18. Seabed morphology and sedimentary processes on high-gradient trough mouth fans offshore Troms, northern Norway

    Science.gov (United States)

    Rydningen, Tom Arne; Laberg, Jan Sverre; Kolstad, Vidar

    2015-10-01

    Trough mouth fans (TMF) situated at the mouths of formerly glaciated cross-shelf troughs are important paleoclimatic archives. Whereas the sedimentary processes of large, low-gradient TMFs have received considerable interest, little attention has been paid to the other end member of this landform class, i.e. TMFs with higher slope gradients. Detailed swath-bathymetric data and seismic profiles from the continental margin offshore Troms, northern Norway cover three high-gradient TMFs (the Andfjorden, Malangsdjupet and Rebbenesdjupet TMFs; slope gradients generally between 1° and 15°), as well as inter-fan areas, which include two submarine canyons (the Andøya and Senja Canyon) and the Malangsgrunnen inter-fan slope. The present-day morphologies of the Andfjorden and Malangsdjupet TMFs have evolved from sediment transport and distribution through gully-channel complexes. The Andfjorden TMF has later been affected by a large submarine landslide that remobilized much of these complexes. The Rebbenesdjupet TMF is dominated by a number of small and relatively shallow slide scars, which are inferred to be related to small-scale sediment failure of glaciomarine and/or contouritic sediments. The canyons cut into the adjacent TMFs, and turbidity currents originating on the fans widened and deepened the canyons during downslope flow. The Malangsgrunnen shelf break and inter-fan slope acted as a funnel for turbidity currents originating on the upper slope, forming a dendritic pattern of gullies. A conceptual model for the high-gradient TMFs on the Troms margin has been compiled. The main sediment input onto the TMFs has occurred during peak glacials when the Fennoscandian Ice Sheet reached the shelf edge. The overall convex fan form and progradational seismic facies show that these glacigenic deposits were repeatedly distributed onto the fan. On the Andfjorden and Malangsdjupet TMFs, gully-channel complexes occur within such deposits. It is thus inferred that the steep

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

    Science.gov (United States)

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

    2017-12-01

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

  20. Submarine hydrodynamics

    CERN Document Server

    Renilson, Martin

    2015-01-01

    This book adopts a practical approach and presents recent research together with applications in real submarine design and operation. Topics covered include hydrostatics, manoeuvring, resistance and propulsion of submarines. The author briefly reviews basic concepts in ship hydrodynamics and goes on to show how they are applied to submarines, including a look at the use of physical model experiments. The issues associated with manoeuvring in both the horizontal and vertical planes are explained, and readers will discover suggested criteria for stability, along with rudder and hydroplane effectiveness. The book includes a section on appendage design which includes information on sail design, different arrangements of bow planes and alternative stern configurations. Other themes explored in this book include hydro-acoustic performance, the components of resistance and the effect of hull shape. Readers will value the author’s applied experience as well as the empirical expressions that are presented for use a...

  1. Submarine glaciated landscapes of central and northern British Columbia, Canada

    Science.gov (United States)

    Shaw, John; Lintern, Gwyn

    2015-04-01

    Recent systematic multibeam sonar mapping and ground-truthing surveys in the fjords and coastal waters of central and northern British Columbia, Canada, provide information on glacial processes associated with the Cordilleran Ice Sheet, and also on postglacial processes that have strongly modified the glacial terrain. During the last glacial maximum, ice covered the Coast Range, except for nunataks. Convergent streamlined glacial landforms in the Strait of Georgia testify to a strong flow of ice towards the southeast, between Vancouver Island and the mainland. During ice retreat, thick deposits of acoustically stratified glaciomarine mud were deposited in glacially over deepened basins. Retreat through the Douglas Channel fjord system was punctuated by still stands, resulting in a series of submarine moraines. Postglacial processes have created a suite of landforms that mask the primary glacial terrain: 1) Fjord floors host thick deposits of acoustically transparent postglacial mud with highly variable distribution: banks up to 80-m thick are commonly adjacent to erosional zones with glaciomarine mud exposed at the seafloor; 2) In this region of high precipitation and snowpack melt, numerous cone-shaped Holocene fan deltas developed on the fjord sidewalls transport coarse sediment to the fjord floors. Larger deltas are developed at fjord heads, notably at Kitimat and Kildala; 3) Submarine slope failures in this tectonically active area have resulted in a suite of mass transport deposits on sidewalls and fjord floors. The very large submarine slope failures at Camano Sound and KitKat Inlet occurred on the steep, rear facets of large transverse moraines, and involved the failure of glaciomarine sediment that moved into deeper basins, perhaps as a retrogressive failure. The ages of these events are unknown, although the presence of postglacial mud in the slide scar at Caamano suggests that the event at that location occurred in the late glacial or early Holocene. Also

  2. Resedimented salt deposits

    Energy Technology Data Exchange (ETDEWEB)

    Slaczka, A.; Kolasa, K. (Jagiellonian Univ., Krakow (Poland))

    1988-08-01

    Carparthian foredeep's Wieliczka salt mine, unique gravity deposits were lately distinguished. They are mainly built of salt particles and blocks with a small admixture of fragments of Miocene marls and Carpathian rocks, deposited on precipitated salt. The pattern of sediment distribution is similar to a submarine fan. Gravels are dominant in the upper part and sands in lower levels, creating a series of lobes. Coarse-grained deposits are represented by disorganized, self-supported conglomerates passing into matrix-supported ones, locally with gradation, and pebbly sandstones consisting of salt grains and scattered boulder-size clasts. The latter may show in the upper part of a single bed as indistinct cross-bedding and parallel lamination. These sediments are interpreted as debris-flow and high-density turbidity current deposits. Salt sandstones (saltstones) which build a lower part of the fan often show Bouma sequences and are interpreted as turbidity-current deposits. The fan deposits are covered by a thick series of debrites (olistostromes) which consist of clay matrix with salt grains and boulders. The latter as represented by huge (up to 100,000 m{sup 3}) salt blocks, fragments of Miocene marls and Carpathian rocks. These salt debrites represent slumps and debris-flow deposits. The material for resedimented deposits was derived from the southern part of the salt basin and from the adjacent, advancing Carpathian orogen. The authors believe the distinct coarsening-upward sequence of the series is the result of progressive intensification of tectonic movements with paroxysm during the sedimentation of salt debrites (about 15 Ma).

  3. Deposition of fan-shaped ZnMoO{sub 4} on ZnCo{sub 2}O{sub 4} nanowire arrays for high electrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zihao; Zhang, Xiaojun [Anhui Normal University, Key Laboratory for Functional Molecular Solids of the Education Ministry of China, Center for Nano Science and Technology, College of Chemistry and Materials Science, Wuhu (China)

    2017-04-15

    In this research, fan-shaped ZnMoO{sub 4} is deposited on flower-like ZnCo{sub 2}O{sub 4} nanowire arrays by two-step hydrothermal method. ZnCo{sub 2}O{sub 4} nanowire is synthesized first and used as the backbone to support ZnMoO{sub 4}. The flower-like ZnCo{sub 2}O{sub 4} nanowire arrays are fully overspread by ZnMoO{sub 4}. And this unique structure shows a high capacitance of 1506 F g{sup -1} when used as electrode for supercapacitor at a current density of 1 A g{sup -1} and a good cycling ability (5000 cycles). (orig.)

  4. Soft-sediment deformation related to syntectonic intraformational unconformity in the early Palaeocene alluvial-fan deposits of Kuşcular Formation in the Elazığ sector of Tauride foreland, eastern Turkey

    Science.gov (United States)

    Koç Taşgın, Calibe

    2017-10-01

    The Kuşçular Formation was deposited in the early Palaeocene in a tectonically-controlled foreland basin in front of the southwards-advancing nappes of the Tauride orogen in eastern Turkey. This lithostratigraphic unit consists of alluvial-fan deposits, including distal mudflat-playa facies association. The proximal to middle fan deposits are composed of clastic sediments, whereas the distal deposits represent both clastic and evaporitic sedimentation. Compressional synsedimentary deformation caused development of an intraformational unconformity in the distal fan deposits of the Kuşçular Formation. Slump features and overturned beds were formed as a result of the oversteepening and recumbent folding of deposits due to the orogen thrust-wedge movement. Load casts, flame structures, intrusion features, sand dykes, interpenetrative cusps and synsedimentary faults were formed as a result of sediment liquefaction and remobilization. It is suggested that such levels of soft-sediment deformation in foreland terrestrial molasse deposits should be carefully studied as they may be related to 'hidden' unconformities and represent an important record of syndepositional tectonic and seismic activity in the basin.

  5. Depth profiles of resistivity and spectral IP for active modern submarine hydrothermal deposits: a case study from the Iheya North Knoll and the Iheya Minor Ridge in Okinawa Trough, Japan

    Science.gov (United States)

    Komori, Shogo; Masaki, Yuka; Tanikawa, Wataru; Torimoto, Junji; Ohta, Yusuke; Makio, Masato; Maeda, Lena; Ishibashi, Jun-ichiro; Nozaki, Tatsuo; Tadai, Osamu; Kumagai, Hidenori

    2017-08-01

    Submarine hydrothermal deposits are one of the promising seafloor mineral resources, because they can store a large amount of metallic minerals as sulfides. The present study focuses on the electrical properties of active modern submarine hydrothermal deposits, in order to provide constraints on the interpretation of electrical structures obtained from marine electromagnetic surveys. Measurements of resistivity and spectral induced polarization (IP) were made using drillcore samples taken from the Iheya North Knoll and the Iheya Minor Ridge in Okinawa Trough, Japan. These hydrothermal sediments are dominantly composed of disseminated sulfides, with minor amounts of massive sulfide rocks. The depth profiles of resistivity and spectral IP properties were successfully revealed to correspond well to layer-by-layer lithological features. Comparison with other physical properties and occurrence of constituent minerals showed that resistivity is essentially sensitive to the connectivity of interstitial fluids, rather than by sulfide and clay content. This suggests that, in active modern submarine hydrothermal systems, not only typical massive sulfide rocks but also high-temperature hydrothermal fluids could be imaged as low-resistivity anomalies in seabed surveys. The spectral IP signature was shown to be sensitive to the presence or absence of sulfide minerals, and total chargeability is positively correlated with sulfide mineral abundance. In addition, the massive sulfide rock exhibits the distinctive IP feature that the phase steadily increases with a decrease of frequency. These results show the effective usage of IP for developing and improving marine IP exploration techniques.[Figure not available: see fulltext.

  6. Deposition and deformation of stratified rocks in the northern Nia Mensa region of Valles Marineris, Mars

    Science.gov (United States)

    Okubo, C. H.

    2016-12-01

    Large-scale structural and geologic mapping based on HiRISE (High Resolution Imaging Science Experiment) digital elevation models reveals new details of the depositional environment for the stratified rocks in the northern Nia Mensa region of eastern Candor Chasma, Valles Marineris, Mars. The map area encompasses the contact between massive sedimentary rocks that comprise most of Nia Mensa and the stratified sedimentary and mass-wasting deposits exposed between Nia Mensa and the north wall of eastern Candor Chasma. The area contains a stratified fan-like deposit on the lower slopes of Nia Mensa. The strata within this deposit dip outward at < 10°, away from its morphologic apex, consistent with an origin as a depositional fan (rather than being carved into a fan shape by erosion). Whether this fan has a subaerial or submarine origin has not yet been determined. Additionally, the fan and surrounding stratified rocks exhibit evidence of soft-sediment deformation in the form of clastic dikes and contorted bedding, indicating that these deposits were water-saturated at the time of deformation. Finally, the northern section of the map area encompasses part of a fractured rise, and deposits interpreted as mud flows mantle the top of this rise. Inferred flow directions suggest that the mud erupted out of these fractures. These findings place constraints on the depositional environment of the local stratified bedrock. The presence of the fan deposit indicates that lateral transport was a component in the depositional history of these sediments. Therefore the sediments did not form entirely as a mantling deposit, such as air fall ash or sediments settled out of a water column. The soft-sediment deformation and subsurface mobilized sediments indicate that groundwater was present in the area after emplacement of the stratified deposits, but before its lithification. These findings point to a wet-playa to lacustrine depositional environment.

  7. The timing of sediment transport down Monterey Submarine Canyon, offshore California

    Science.gov (United States)

    Stevens, Thomas; Paull, Charles K.; Ussler, William III; McGann, Mary; Buylaert, Jan-Pieter; Lundsten, Eve M.

    2013-01-01

    While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages measured on benthic foraminifera to examine the timing of sediment transport through the axial channel of Monterey Submarine Canyon and Fan, offshore California. The OSL ages date the timing of sediment entry into the canyon head while the 14C ages of benthic foraminifera record the deposition of hemipelagic sediments that bound the sand horizons. We use both single-grain and small (∼2 mm area) single-aliquot regeneration approaches on vibracore samples from fining-upward sequences at various water depths to demonstrate relatively rapid, decadal-scale sand transport to at least 1.1 km depth and more variable decadal- to millennial-scale transport to a least 3.5 km depth on the fan. Significant differences between the time sand was last exposed at the canyon head (OSL age) and the timing of deposition of the sand (from 14C ages of benthic foraminifera in bracketing hemipelagic sediments) are interpreted as indicating that the sand does not pass through the entire canyon instantly in large individual events, but rather moves multiple times before emerging onto the fan. The increased spread in single-grain OSL dates with water depth provides evidence of mixing and temporary storage of sediment as it moves through the canyon system. The ages also indicate that the frequency of sediment transport events decreases with distance down the canyon channel system. The amalgamated sands near the canyon head yield OSL ages that are consistent with a sub-decadal recurrence frequency while the fining-upward sand sequences on the fan indicate that the channel is still experiencing events with a 150

  8. Displaced/re-worked rhodolith deposits infilling parts of a complex Miocene multistorey submarine channel: A case history from the Sassari area (Sardinia, Italy)

    Science.gov (United States)

    Murru, Marco; Bassi, Davide; Simone, Lucia

    2015-08-01

    In the Sassari area (north-western Sardinia, Italy), the Miocene Porto Torres sub-basin sequences represent the complex multistorey mixed carbonate-siliciclastic submarine feature called the Sassari Channel. During the late Burdigalian-early Serravallian, repeated terrigenous supplies from uplifted Paleozoic crystalline substrata fed the Sassari Channel system by means of turbidity and locally hyper-concentrated turbidity flows. Shelfal areas were the source of terrigenous clasts, but open shelf rhodalgal/foramol carbonate areas were very productive and largely also contributed to the channel infilling. Re-worked sands and skeletal debris were discontinuously re-sedimented offshore as pure terrigenous, mixed and/or carbonate deposits. Major sediment supply was introduced between the latest Burdigalian and the start of the middle Langhian, during which a large amount of carbonate, mixed and siliciclastic sediments reached the Porto Torres Basin (Sassari Channel I). Contributions from shallow proximal source areas typify the lower intervals (Unit A) in marginal sectors of the channel. Upward, these evolve into autochthonous rhodolith deposits, winnowed by strong currents in relatively shallow well lit settings within a complex network of narrow tidally-controlled channels (Unit D) locally bearing coral assemblages. Conversely, re-sedimented rhodoliths from the Units B and C accumulated under conditions of higher turbidity. In deeper parts of the channel taxonomically diversified rhodoliths point to the mixing of re-deposited skeletal components from different relatively deep bathmetric settings. In the latest early Langhian, major re-sedimentation episodes, resulting in large prograding bodies (Unit D), triggered by repeated regression pulses in a frame of persistent still stand. During these episodes photophile assemblages dwelled in the elevated margin sectors of the channel. A significant latest early Langhian drop in relative sea-level resulted in impressive mass

  9. Highly dynamic sediment deposition in modern times on the submarine Amazon Delta - First results from the AMADEUS project (Cruise MSM 20/3, February/March 2012)

    Science.gov (United States)

    Schwenk, T.; Mulitza, S.; Chiessi, C.; Haberkern, J.; Wiers, S.

    2012-12-01

    The submarine Amazon Delta is the major sink for the enormous sediment load of the Amazon River during modern times. Supported by its large drainage area (7 M km2) and the huge total run-off of 6300 km3/yr, which is 20% of the global run-off into the oceans, the Amazon River discharges the worldwide highest total sediment load to the oceans, namely 1200 Mt/yr. Characterized by sedimentation rates of decimeters per year, the submarine Amazon Delta can act as an ultra-high resolution archive of the Anthropocene climatic history of the Amazon basin. However, it has to be kept in mind that the accumulation on the delta is controlled by an interaction of sediment supply and the shelf current pattern including strong tides. To study in general the response of Amazon sedimentation to deforestation, land use and climate variability, the Project AMADEUS has been established in cooperation between the MARUM, Bremen, Germany and the University of Sao Paulo, Brazil. Within this project a first cruise was carried out with the RV Maria S. Merian in February/March 2012 in order to collect high-resolution seismic data (Mini GI Gun, 50 m analogue streamer), sediment echosounder data (Parasound; 4 kHz, 18 kHz, 40 kHz), swath-sounder data (bathymetry and backscatter), sediment samples and water column samples in front of the Amazon River mouth. The presentation will focus mainly on the seismo-acoustic data sets. As a first step, the data were analyzed to understand the internal architecture of the recent clinoform build-up in time and space. The main emphasis were set on the foreset and bottomset, where most of the accretion occur, to allow volume and sediment budget calculations in relation to the denudation history of the Amazon basin. Especially the Parasound data reveal significant changes of the clinoform along the delta front in terms of thickness, slope angle, shape (oblique-sigmoidal-convex) and internal architecture (especially depths and character of erosional

  10. Effective transport of event sediments from shelf to deep-sea through submarine canyon: Examples from the Japan and Ryukyu trench forearc

    Science.gov (United States)

    Ikehara, K.; Kanamatsu, T.; Usami, K.

    2016-02-01

    Large earthquakes and their related tsunamis resuspend and remobilize unconsolidated shallow marine sediments. Some of the resuspended grains form the dense water masses, and move downslope-ward gravitationally. Confined bathymetry of submarine canyon may play an important role on maintaining their density, and protecting dispersion and dilution of their bodies, and further leading the long-distance transport of the sediment grains from shelf to deep-sea. The 2011 Tohoku-oki earthquake and tsunami made erosion and resuspension of shelf sediments at the wide areas along the Tohoku coast. Although generation of tsunami-induced turbidity currents was reported, there are only a few examples of the shelf sediment transport to deep-sea. Weak development of submarine canyons at the upper slope may explain this phenomena. On the other hand, many turbidites were observed in the sediment cores collected from a submarine fan at a forearc basin along the southern Ryukyu Trench. A lot of bioclastic (carbonate) coarse grains of shallow marine origin composed the turbidites. Deep incision of submarine canyons along the upper forearc slope may contribute the effective transport of coarse bioclasts from shelf to deep-sea in this area. No or few submarine canyon connecting the shelf with the trench floor makes the different source of the trench fill deposits at both trenchs.

  11. Sulfur, carbon, and oxygen isotope variations in submarine hydrothermal deposits of Guaymas Basin, Gulf of California, USA

    Science.gov (United States)

    Peter, J.M.; Shanks, Wayne C.

    1992-01-01

    Sulfur, carbon, and oxygen isotope values were measured in sulfide, sulfate, and carbonate from hydrothermal chimney, spire, and mound samples in the southern trough of Guaymas Basin, Gulf of California, USA. ??34S values of sulfides range from -3.7 to 4.5%. and indicate that sulfur originated from several sources: 1. (1) dissolution of 0??? sulfide contained within basaltic rocks, 2. (2) thermal reduction of seawater sulfate during sediment alteration reactions in feeder zones to give sulfide with positive ??34S, and 3. (3) entrainment or leaching of isotopically light (negative-??34S) bacteriogenic sulfide from sediments underlying the deposits. ??34S of barite and anhydrite indicate sulfur derivation mainly from unfractionated seawater sulfate, although some samples show evidence of sulfate reduction and sulfide oxidation reactions during mixing within chimneys. Oxygen isotope temperatures calculated for chimney calcites are in reasonable agreement with measured vent fluid temperatures and fluid inclusion trapping temperatures. Hydrothermal fluids that formed calcite-rich chimneys in the southern trough of Guaymas Basin were enriched in 18O with respect to seawater by about 2.4??? due to isotopic exchange with sedimentary and/or basaltic rocks. Carbon isotope values of calcite range from -9.6 to -14.0??? ??34CpDB, indicating that carbon was derived in approximately equal quantities from the dissolution of marine carbonate minerals and the oxidation of organic matter during migration of hydrothermal fluid through the underlying sediment column. Statistically significant positive, linear correlations of ??34S, ??34C, and ??18O of sulfides and calcites with geographic location within the southern trough of Guaymas Basin are best explained by variations in water/rock ( w r) ratios or sediment reactivity within subsurface alteration zones. Low w r ratios and the leaching of detrital carbonates and bacteriogenic sulfides at the southern vent sites result in relatively

  12. Submarine Medicine Team

    Data.gov (United States)

    Federal Laboratory Consortium — The Submarine Medicine Team conducts basic and applied research on biomedical aspects of submarine and diving environments. It focuses on ways to optimize the health...

  13. Sloping fan travertine, Belen, New Mexico, USA

    Science.gov (United States)

    Cook, Megan; Chafetz, Henry S.

    2017-05-01

    Pliocene to Quaternary age travertines are very well-exposed in quarries near Belen, New Mexico, U.S.A., on the western edge of the Rio Grande Rift system. A series of hillside springs produced travertine tongues tens of meters thick and hundreds of meters long. The accumulations represent deposits from individual springs as well as the amalgamation of deposits. The overall architecture is predominantly composed of sloping fans with a smaller component of terrace mounds. The sloping fan deposits commonly have a dip of rock, sheets and rafts, and finely crystalline crusts that occur throughout the sloping fan and terrace mound accumulations. Sheets and rafts formed as precipitates in pools on the surfaces of the fans and terraces as well as spelean deposits on the water surfaces of pools within cavities in the overall accumulation. Thus, the spelean rafts provide valuable indicators of original horizontality in the sloping fan strata. In addition, intraformational breccias, composed of locally torn-up travertine intraclastic boulders and deposited in with other travertine, and extraformational breccias, composed of torn-up travertine intraclasts mixed with siliciclastic fines and sand and Paleozoic limestone clasts transported downslope from higher on the hillside, are a common constituent in the sloping fan accumulation. The Belen travertines provide a very well-exposed example of sloping fan travertines and may provide relevant data with regard to the subsurface Aptian Pre-Salt deposits, offshore Brazil.

  14. Experimental Analysis on Flow Expansion Over Fan

    Science.gov (United States)

    Sittoni, L.; Paola, C.

    2005-12-01

    We present experimental evidence on the occurrence of large angles of flow expansion with no flow separation over depositional fans. The evolution of a number of self-formed experimental fans was analyzed using overhead images and detailed topographic surveys. Angles of flow expansion up to 45 degrees were found in association with a characteristic bed curvature. Although precise measurements indicate that transverse curvature appeared to slightly decrease downstream over the fans, an approximately constant value of curvature of about 0.1 (r/W = 0.1, where r is the dimensional curvature and W is the maximum width of the fan) fits well all fan sections analyzed. In addition, we found that bed curvature shows a weak proportional dependence with fan expansion angles (alpha around 20 degrees, where alpha is the local plan angle). The curvature appears sufficient to explain the common occurrence of unchannelized, simple fans with opening angles, and hence rates of bedload divergence, much larger than would be predicted from jet theory. We have also analyzed fan development. In our experiments, an instability phenomenon causes a sudden increase in channel width, in association with the formation of a scour. A common development pattern was observed: the upstream-migrating scour initiates flow expansion, inducing in turn the formation of a transient concave heart-shaped fan shape that then slowly develops into a final, steady cone-shaped deposit. Most of the deposition appears to occur during the initial expansion phase. During final steady conditions, fans were also observed to reach values of L/0.5W (L is the final fan length and W is the fan width) approximately constant and in the range 2-4.

  15. Analysis of Submarine Landslides and Canyons along the U.S. Atlantic Margin Using Extended Continental Shelf Mapping Data

    Science.gov (United States)

    Chaytor, J. D.; Brothers, D. S.; Ten Brink, U. S.; Hoy, S. K.; Baxter, C.; Andrews, B.

    2013-12-01

    U.S. Geological Survey (USGS) studies of the U.S. Atlantic continental slope and rise aim to understand the: 1) the role of submarine landslides in tsunami generation, and 2) the linkages between margin morphology and sedimentary processes, particularly in and around submarine canyon systems. Data from U.S. Extended Continental Shelf (ECS) and numerous subsequent mapping surveys have facilitated the identification and characterization of submarine landslides and related features in fine detail over an unprecedented spatial extent. Ongoing analysis of USGS collected piston cores, sub-bottom and multichannel seismic (MCS) reflection profiles, and an extensive suite of legacy MCS data from two landslides, the Southern New England landslide zone and the Currituck Landslide, suggest that the most recent major landslide events are pre-Holocene, but that failures were complex and most likely multi-phase, at times resulting in extensive overlapping debris deposits. Piston core records plus visual observations of the seafloor from recent TowCam deployments and NOAA Ship Okeanos Explorer ROV dives reveal ongoing development of colluvial wedge-style debris aprons at the base of scarps within these landslides, showing that these regions continue to evolve long after the initial failure events. Multibeam bathymetry data and MCS profiles along the upper slope reveal evidence for vertical fluid migration and possible seabed gas expulsion. These observations underscore the need to reevaluate the sources of pore fluid overpressure in slope sediments and their role in landslide generation. ECS and more recent multibeam mapping have provided the opportunity to investigate the full extent of submarine canyon morphology and evolution from Cape Hatteras up to the US-Canadian EEZ, which has led to better understanding of the important role of antecedent margin physiography on their development. Six submarine canyon systems along the margin (Veatch, Hydrographer, Hudson, Wilmington

  16. Understanding Himalayan erosion and the significance of the Nicobar Fan

    Science.gov (United States)

    McNeill, Lisa C.; Dugan, Brandon; Backman, Jan; Pickering, Kevin T.; Pouderoux, Hugo F. A.; Henstock, Timothy J.; Petronotis, Katerina E.; Carter, Andrew; Chemale, Farid; Milliken, Kitty L.; Kutterolf, Steffen; Mukoyoshi, Hideki; Chen, Wenhuang; Kachovich, Sarah; Mitchison, Freya L.; Bourlange, Sylvain; Colson, Tobias A.; Frederik, Marina C. G.; Guèrin, Gilles; Hamahashi, Mari; House, Brian M.; Hüpers, Andre; Jeppson, Tamara N.; Kenigsberg, Abby R.; Kuranaga, Mebae; Nair, Nisha; Owari, Satoko; Shan, Yehua; Song, Insun; Torres, Marta E.; Vannucchi, Paola; Vrolijk, Peter J.; Yang, Tao; Zhao, Xixi; Thomas, Ellen

    2017-10-01

    A holistic view of the Bengal-Nicobar Fan system requires sampling the full sedimentary section of the Nicobar Fan, which was achieved for the first time by International Ocean Discovery Program (IODP) Expedition 362 west of North Sumatra. We identified a distinct rise in sediment accumulation rate (SAR) beginning ∼9.5 Ma and reaching 250-350 m/Myr in the 9.5-2 Ma interval, which equal or far exceed rates on the Bengal Fan at similar latitudes. This marked rise in SAR and a constant Himalayan-derived provenance necessitates a major restructuring of sediment routing in the Bengal-Nicobar submarine fan. This coincides with the inversion of the Eastern Himalayan Shillong Plateau and encroachment of the west-propagating Indo-Burmese wedge, which reduced continental accommodation space and increased sediment supply directly to the fan. Our results challenge a commonly held view that changes in sediment flux seen in the Bengal-Nicobar submarine fan were caused by discrete tectonic or climatic events acting on the Himalayan-Tibetan Plateau. Instead, an interplay of tectonic and climatic processes caused the fan system to develop by punctuated changes rather than gradual progradation.

  17. Submarine landslides: processes, triggers and hazard prediction.

    Science.gov (United States)

    Masson, D G; Harbitz, C B; Wynn, R B; Pedersen, G; Løvholt, F

    2006-08-15

    Huge landslides, mobilizing hundreds to thousands of km(3) of sediment and rock are ubiquitous in submarine settings ranging from the steepest volcanic island slopes to the gentlest muddy slopes of submarine deltas. Here, we summarize current knowledge of such landslides and the problems of assessing their hazard potential. The major hazards related to submarine landslides include destruction of seabed infrastructure, collapse of coastal areas into the sea and landslide-generated tsunamis. Most submarine slopes are inherently stable. Elevated pore pressures (leading to decreased frictional resistance to sliding) and specific weak layers within stratified sequences appear to be the key factors influencing landslide occurrence. Elevated pore pressures can result from normal depositional processes or from transient processes such as earthquake shaking; historical evidence suggests that the majority of large submarine landslides are triggered by earthquakes. Because of their tsunamigenic potential, ocean-island flank collapses and rockslides in fjords have been identified as the most dangerous of all landslide related hazards. Published models of ocean-island landslides mainly examine 'worst-case scenarios' that have a low probability of occurrence. Areas prone to submarine landsliding are relatively easy to identify, but we are still some way from being able to forecast individual events with precision. Monitoring of critical areas where landslides might be imminent and modelling landslide consequences so that appropriate mitigation strategies can be developed would appear to be areas where advances on current practice are possible.

  18. Submarine landslides: advances and challenges

    Science.gov (United States)

    Locat, Jacques; Lee, Homa J.

    2002-01-01

    Due to the recent development of well-integrated surveying techniques of the sea floor, significant improvements were achieved in mapping and describing the morphology and architecture of submarine mass movements. Except for the occurrence of turbidity currents, the aquatic environment (marine and fresh water) experiences the same type of mass failure as that found on land. Submarine mass movements, however, can have run-out distances in excess of 100 km, so their impact on any offshore activity needs to be integrated over a wide area. This great mobility of submarinemass movements is still not very well understood, particularly for cases like the far-reaching debris flows mapped on the Mississippi Fan and the large submarine rock avalanches found around many volcanic islands. A major challenge ahead is the integration of mass movement mechanics in an appropriate evaluation of the hazard so that proper risk assessment methodologies can be developed and implemented for various human activities offshore, including the development of natural resources and the establishment of reliable communication corridors. Key words : submarine slides, hazards, risk assessment, morphology, mobility, tsunami. Le dveloppement rcent de techniques de levs hydrograhiques pour les fonds marins nous a permis d'atteindre une qualit ingale dans la cartographie et la description des glissements sous marins. l'exception des courants de turbidit, on retrouve dans le domaine aquatique les mmes types de mouvements de terrain que sur terre. Par contre, les glissements sous-marins peuvent atteindre des distances excdant 100 km de telle sorte que leur impact sur les activits offshore doit tre pris en compte sur degrandes tendues. La grande mobilit des glissements sous-marins n'est pas encore bien comprise, comme pour le cas des coules dedbris cartographies sur le cne du Mississippi ainsi que pour les grandes avalanches rocheuses sous-marines retrouves au pourtour des les volcaniques. Un dfi majeur

  19. Sea-level-induced seismicity and submarine landslide occurrence

    Science.gov (United States)

    Brothers, Daniel S.; Luttrell, Karen M.; Chaytor, Jason D.

    2013-01-01

    The temporal coincidence between rapid late Pleistocene sea-level rise and large-scale slope failures is widely documented. Nevertheless, the physical mechanisms that link these phenomena are poorly understood, particularly along nonglaciated margins. Here we investigate the causal relationships between rapid sea-level rise, flexural stress loading, and increased seismicity rates along passive margins. We find that Coulomb failure stress across fault systems of passive continental margins may have increased more than 1 MPa during rapid late Pleistocene–early Holocene sea-level rise, an amount sufficient to trigger fault reactivation and rupture. These results suggest that sea-level–modulated seismicity may have contributed to a number of poorly understood but widely observed phenomena, including (1) increased frequency of large-scale submarine landslides during rapid, late Pleistocene sea-level rise; (2) emplacement of coarse-grained mass transport deposits on deep-sea fans during the early stages of marine transgression; and (3) the unroofing and release of methane gas sequestered in continental slope sediments.

  20. Experimental Study of Alluvial Fan Formation

    Science.gov (United States)

    Delorme, P.; Devauchelle, O.; Barrier, L.; Métivier, F.

    2015-12-01

    At the outlet of mountain ranges, rivers flow onto flatter lowlands. The associated change of slope causes sediment deposition. As the river is free to move laterally, it builds conical sedimentary structures called alluvial fans. Their location at the interface between erosional and depositional areas makes them valuable sedimentary archives. To decipher these sedimentary records, we need to understand the dynamics of their growth. Most natural fans are built by braided streams. However, to avoid the complexity of braided rivers, we develop a small-scale experiment in which an alluvial fan is formed by a single channel. We use a mixture of water and glycerol to produce a laminar river. The fluid is mixed with corindon sand (~ 300 μm) in a tilted channel and left free to form a fan around its outlet. The sediment and water discharges are constant during an experimental run. We record the fan progradation and the channel morphology with top-view pictures. We also generate an elevation map with an optical method based on the deformation of a moiré pattern. We observe that, to leading order, the fan remains self-affine as it grows, with a constant slope. We compare two recent studies about the formation of one-dimensionnal fan [Guerit et al. 2014] and threshold rivers [Seizilles et al. 2013] to our experimental findings. In particular, we propose a theory witch relates the fan morphology to the control parameters ( fluid and sediment discharges, grain size). Our observation accord with the predictions, suggesting that the fan is built near the threshold of sediment motion. Finally, we intend to expand our interpretation to alluvial fans build by single-thread channels ( Okavango, Bostwana; Taquari and Paraguay, Brasil; Pastaza, Peru).

  1. Depositional conditions on an alluvial fan at the turn of the Weichselian to the Holocene – a case study in the Żmigród Basin, southwest Poland

    Directory of Open Access Journals (Sweden)

    Zieliński Paweł

    2016-06-01

    Full Text Available Presented are the results of research into the fluvio-aeolian sedimentary succession at the site of Postolin in the Żmigród Basin, southwest Poland. Based on lithofacies analysis, textural analysis, Thermoluminescence and Infrared-Optical Stimulated Luminescence dating and GIS analysis, three lithofacies units were recognised and their stratigraphic succession identified: 1 the lower unit was deposited during the Pleni-Weichselian within a sand-bed braided river functioning under permafrost conditions within the central part of the alluvial fan; 2 the middle unit is the result of aeolian deposition and fluvial redeposition on the surface of the fan during long-term permafrost and progressive decrease of humidity of the climate at the turn of the Pleni- to the Late Weichselian; 3 the upper unit accumulated following the development of longitudinal dunes at the turn of the Late Weichselian to the Holocene; the development of dunes was interrupted twice by the form being stabilised by vegetation and soil development.

  2. Low cost submarine robot

    OpenAIRE

    Ponlachart Chotikarn; Werapong Koedsin; Boonlua Phongdara; Pattara Aiyarak

    2010-01-01

    A submarine robot is a semi-autonomous submarine robot used mainly for marine environmental research. We aim todevelop a low cost, semi-autonomous submarine robot which is able to travel underwater. The robot’s structure was designedand patented using a novel idea of the diving system employing a volume adjustment mechanism to vary the robot’s density.A light weight, flexibility and small structure provided by PVC can be used to construct the torpedo-liked shape robot.Hydraulic seal and O-rin...

  3. Low cost submarine robot

    Directory of Open Access Journals (Sweden)

    Ponlachart Chotikarn

    2010-10-01

    Full Text Available A submarine robot is a semi-autonomous submarine robot used mainly for marine environmental research. We aim todevelop a low cost, semi-autonomous submarine robot which is able to travel underwater. The robot’s structure was designedand patented using a novel idea of the diving system employing a volume adjustment mechanism to vary the robot’s density.A light weight, flexibility and small structure provided by PVC can be used to construct the torpedo-liked shape robot.Hydraulic seal and O-ring rubbers are used to prevent water leaking. This robot is controlled by a wired communicationsystem.

  4. The Late Cambrian Takaka Terrane, NW Nelson, New Zealand: Accretionary-prism development and arc collision followed by extension and fan-delta deposition at the SE margin of Gondwana

    Science.gov (United States)

    Pound, K. S.

    2013-12-01

    Re-evaluation of field and lab data indicates that the Cambrian portion of the Takaka Terrane in the Cobb Valley area of NW Nelson, New Zealand preserves the remnants of an accretionary prism complex, across which the Lockett Conglomerate fan-delta was deposited as a consequence of extension. Previous work has recognized that the structurally disrupted lower Takaka Terrane rocks present an amalgam of sedimentary and igneous rocks generated prior to convergence (Junction Formation) or during convergence (Devil River Volcanics Group, Haupiri Group), including arc-related and MORB components. Portions of the sequence have in the past been loosely described as an accretionary prism. Reevaluation of the detailed mapping, sedimentological and provenance studies shows that remnants of a stratigraphic sequence (Junction Formation, Devil River Volcanics Group, Haupiri Group) can be traced through 10 fault-bounded slices, which include a mélange-dominated slice (Balloon Mélange). These slices are the remnants of the accretionary prism; the stratigraphy within each slice generally youngs to the east, and the overall pattern of aging (based on relative age from provenance studies, sparse fossils, stratigraphic relations, and limited isotopic data) indicates that the older rocks generally dominate fault slices to the east, and younger rocks dominate fault slices to the west, delineating imbricate slices within an eastward-dipping subduction zone, in which the faults record a complex history of multi-phase reactivation. The Lockett Conglomerate is a ~500-m thick fan-delta conglomerate that is the preserved within one of the fault slices, where it is stratigraphically and structurally highest unit in the lower Takaka Terrane; it is also present as blocks within the Balloon Melange. The Lockett Conglomerate is marine at its base and transitions upwards to fluvial facies. The Lockett Conglomerate has previously been interpreted to result from erosion consequent on continued

  5. A model for sediment capacity of turbidity currents considering sediment-fluid interactions with application to longitudinal equilibrium profile of submarine channels

    Science.gov (United States)

    Naruse, H.

    2016-12-01

    Leveed submarine channels are one of the characteristic architectural elements of submarine fans. Comparing to alluvial rivers, leveed submarine channels are stable and thus turbidity currents inside channels can be supposed to flow at quasi-equilibrium condition. Here, this study proposes a model of sediment concentration of turbidity currents in equilibrium condition (i.e. sediment capacity). The model considers turbulence-suppression effect by density stratification of suspended sediments and concentration-related processes such as hindered settling. The model predicts that turbidity currents can have two different values of sediment capacity: high-concentration and low-concentration capacity. High concentration capacity is attained by positive feedback effect of hindered settling, in which settling velocity of sediment decreases as concentration increases. On the other hand, when density stratification effect becomes dominant, turbidity currents have only low-concentration capacity because the effect has negative feedback effect (sediment entrainment decreases as concentration increases). The initial condition of turbidity currents is a critical factor to determine which condition the flows finally reach. We applied our capacity model to predict the equilibrium profile of submarine channels. The equilibrium profile is here defined as profiles where turbidity currents bypass or deposit uniformly. Grain-size distribution is approximated to two size classes: channel-forming sands and levee-forming muddy sediments. The model can predict shape and length of leveed channels in the equilibrium condition. As a result, it was revealed that the profile varies depending on four variables: aggradation rates, sand/mud ratio in suspended load, total sediment discharge and flow discharge. Sand-prone flows produce short and highly inclined channels whereas mud-prone flows produce long and low-inclination channels. Also, the model implies that long-lived channels are difficult

  6. Provenance of alluvial fan deposits to constrain the mid-term offsets along a strike-slip active fault: the Elsinore fault in the Coyote Mountains, Imperial Valley, California.

    Science.gov (United States)

    Masana, Eulalia; Stepancikova, Petra; Rockwell, Thomas

    2013-04-01

    The lateral variation in rates along a fault and its constancy along time is a matter of discussion. To give light to this discussion, short, mid and long term offset distribution along a fault is needed. Many studies analyze the short-term offset distribution along a strike-slip fault that can be obtained by the analysis of offset features imprinted in the morphology of the near-fault area. We present an example on how to obtain the mid- to long-term offset values based on the composition of alluvial fans that are offset by the fault. The study area is on the southern tip of the Elsinore fault, which controls the mountain front of the Coyote Mountains (California). The Elsinore-Laguna Salada fault is part of the San Andreas fault (SAF) system, extending 250 km from the Los Angeles Basin southeastward into the Gulf of California, in Mexico. The slip-rate on the southern Elsinore fault is believed to be moderate based on recent InSAR observations, although a recent study near Fossil Canyon (southern Coyote Mountains) suggests a rate in the range of 1-2 mm/yr. For this study we processed the airborne LiDAR dataset (EarthScope Southern & Eastern California, SoCal) to map short to mid-term alluvial offsets. We reprocessed the point clouds to produce DEMs with 0.5m and 0.25m grids and we varied the insolation angles to illuminate the various fault strands and the offset features. We identified numerous offset features, such as rills, channel bars, channel walls, alluvial fans, beheaded channels and small erosional basins that varied in displacement from 1 to 350 m. For the mid- to long-term offsets of the alluvial fans we benefited from the diverse petrological composition of their sources. Moreover, we recognized that older alluvium, which is offset by greater amounts, is in some cases buried beneath younger alluvial fan deposits and separated by buried soils. To determine the source canyon of various alluvial elements, we quantified the clast assemblage of each source

  7. Submarine landslide and tsunami hazards offshore southern Alaska: Seismic strengthening versus rapid sedimentation

    Science.gov (United States)

    Sawyer, Derek E.; Reece, Robert S.; Gulick, Sean P. S.; Lenz, Brandi L.

    2017-08-01

    The southern Alaskan offshore margin is prone to submarine landslides and tsunami hazards due to seismically active plate boundaries and extreme sedimentation rates from glacially enhanced mountain erosion. We examine the submarine landslide potential with new shear strength measurements acquired by Integrated Ocean Drilling Program Expedition 341 on the continental slope and Surveyor Fan. These data reveal lower than expected sediment strength. Contrary to other active margins where seismic strengthening enhances slope stability, the high-sedimentation margin offshore southern Alaska behaves like a passive margin from a shear strength perspective. We interpret that seismic strengthening occurs but is offset by high sedimentation rates and overpressure. This conclusion is supported by shear strength outside of the fan that follow an active margin trend. More broadly, seismically active margins with wet-based glaciers are susceptible to submarine landslide hazards because of the combination of high sedimentation rates and earthquake shaking.

  8. Implications from deepwater depositional elements in the fold-and-thrust belt of the remnant ocean basin offshore SW Taiwan

    Science.gov (United States)

    Lin, Liang-Fu; Liu, Char-Shine; Chang, Jih-Hshin

    2017-04-01

    The northeastern South China Sea Basin is being closed due to the oblique collision between the Luzon Volcano Arc and the Chinese Continental Margin. The orogen of Taiwan Island situated in the tropical/subtropical zone with a high uplifting rate provides voluminous sediments to the nearby basins. As a remnant ocean basin, the closing basin in offshore southwestern Taiwan has accommodated a large amount of synorogenic sediments. Through multi-channel seismic profiles, several depositional elements in the deepwater fold-and-thrust belt of the lower Gaoping slope have been identified. These sedimentary layers were deposited before deformation and later incorporated into the orogenic wedge. The N-S trend leveed channels developed along the strike of the orogenic wedge and occupied the most area of the lower Gaoping Slope. This channel-levee complex presents the ancient fan which should relate to the Penghu submarine canyon, named "Penghu Turbidite System". In contrast, at the mouth of the middle section of the Gaoping Submarine Canyon, the buried channels trend SW-NE are characterized by massive high amplitude reflection packets (HARPs) which may represent the coarse grain infills. This facies turns to channelized lobes outward that interfinger with the Penghu Turbidite System. Two different characteristics of submarine fans reflect the different natures of Penghu and Gaoping submarine canyons. Since the tectonic convergence approaching, these two canyons rejuvenated and started to erode the aforementioned deposits. The channels become erosional in the fold-and-thrust belt that most of the sediments bypass through the fold-and-thrust belt or spill into the piggyback accommodations. The newly discovered sedimentary records in this study imply how these two sediment dispersal systems work before and after structuring, which is a puzzle for better understanding the sedimentary history of the remnant ocean basin offshore southwestern Taiwan.

  9. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  10. Experimental alluvial fans: Advances in understanding of fan dynamics and processes

    Science.gov (United States)

    Clarke, Lucy E.

    2015-09-01

    Alluvial fans are depositional systems that develop because of a disparity between the upstream and downstream sediment transport capacity of a system, usually at the base of mountain fronts as rivers emerge from the constrained mountain area onto the plain. They are dynamic landforms that are prone to abrupt changes on a geomorphological (decades to centuries) time scale, while also being long-term deposition features that preserve sedimentary strata and are sensitive indictors of environmental change. The complexity of interactions between catchment characteristics, climate, tectonics, internal system feedbacks, and environmental processes on field alluvial fans means that it is difficult to isolate individual variables in a field setting; therefore, the controlled conditions afforded by experimental models has provided a novel technique to overcome some of these complexities. The use of experimental models of alluvial fans has a long history and these have been implemented over a range of different research areas utilising various experimental designs. Using this technique, important advances have been made in determining the primary factors influencing fan slope, understanding of avulsion dynamics, identifying autogenic processes driving change on fan systems independent of any change in external conditions, and the mechanics of flow and flood risk on alluvial fans, to name a few. However, experiments cannot be carried out in isolation. Thus, combining the findings from experimental alluvial fans with field research and numerical modelling is important and, likewise, using these techniques to inform experimental design. If this can be achieved, there is potential for future experimental developments to explore key alluvial fan issues such as stratigraphic preservation potential and simulating extra terrestrial fan systems.

  11. Distal turbidite fan/lobe succession of the Late Oligocene Zuberec Fm. - architecture and hierarchy (Central Western Carpathians, Orava-Podhale basin)

    Science.gov (United States)

    Starek, Dušan; Fuksi, Tomáš

    2017-08-01

    A part of the Upper Oligocene sand-rich turbidite systems of the Central Carpathian Basin is represented by the Zuberec Formation. Sand/mud-mixed deposits of this formation are well exposed in the northern part of the basin, allowing us to interpret the turbidite succession as terminal lobe deposits of a submarine fan. This interpretation is based on the discrimination of three facies associations that are comparable to different components of distributive lobe deposits in deep-water fan systems. They correspond to the lobe off-axis, lobe fringe and lobe distal fringe depositional subenvironments, respectively. The inferences about the depositional paleoenvironment based on sedimentological observations are verified by statistical analyses. The bed-thickness frequency distributions and vertical organization of the facies associations show cyclic trends at different hierarchical levels that enable us to reconstruct architectural elements of a turbidite fan. First, small-scale trends correspond with shift in the lobe element centroid between successive elements. Differences in the distribution and frequency of sandstone bed thicknesses as well as differences in the shape of bed-thickness frequency distributions between individual facies associations reflect a gradual fining and thinning in a down-dip direction. Second, meso-scale trends are identified within lobes and they generally correspond to the significant periodicity identified by the time series analysis of the bed thicknesses. The meso-scale trends demonstrate shifts in the position of the lobe centroid within the lobe system. Both types of trends have a character of a compensational stacking pattern and could be linked to autogenic processes. Third, a largescale trend documented by generally thickening-upward stacking pattern of beds, accompanied by a general increase of the sandstones/mudstones ratio and by a gradual change of percentage of individual facies, could be comparable to lobe-system scale. This

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

    Science.gov (United States)

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

    2017-08-01

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

  13. Experimental modeling of gravity underflow in submarine channels

    Science.gov (United States)

    Islam, Mohammad Ashraful

    Active and relic meandering channels are common on the seafloor adjacent to continental margins. These channels and their associated submarine fan deposits are products of the density-driven gravity flows known as turbidity currents. Unlike natural rivers, few attempts have been made to explore the process of channel meandering in the submarine environment. This research focuses on resolving the flow field of submarine channels by conducting experiments in a large laboratory basin. Saline and particulate density flows were studied in a straight channel, a single bend sinuous channel with vertical sidewalls and a multiple-bend sinuous channel with sloping sidewalls. Instantaneous velocities in steady developed currents were measured using 3-component acoustic Doppler velocity probes. Excess fractional density was measured at selected locations by collecting water sample using a siphon rake. Turbulent kinetic energy and Reynolds stress components are derived from the instantaneous velocity data of the straight channel experiments. Structure functions for mean velocity, Reynolds stress and turbulent kinetic energy profiles are derived by fitting normalized data. The normalized Reynolds-averaged velocity shows excellent similarity collapse while the Reynolds-stress and the turbulent kinetic energy profiles display reasonable similarity. Vertical profiles of the turbulent kinetic energy display two peaks separated by a zone of low turbulence; the ratio of the maximum to the depth-averaged turbulent kinetic energy is approximately 1.5. Theoretical profile of turbulent kinetic energy is derived. Comparisons of experimentally and theoretically derived turbulent kinetic energy profiles show reasonable agreement except at the position of velocity maximum where the theoretical profile displays a very small value. Velocity profiles derived from the measurements with confined flow in the single bend channel reveal that channel curvature drives two helical flow cells, one

  14. The ASTARTE Paleotsunami and Mass Transport Deposits data bases - web-based references for tsunami and submarine landslide research around Europe

    Science.gov (United States)

    De Martini, Paolo Marco; Patera, Antonio; Orefice, Simone; Paris, Raphael; Völker, David; Lastras, Galderic; Terrinha, Pedro; Noiva, João; Smedile, Alessandra; Pantosti, Daniela; Hunt, James; Gutscher, Marc-Andre; Migeon, Sébastien; Papadopoulos, Gerassimos; Triantafyllou, Ioanna; Yalciner, Ahmet C.

    2017-04-01

    EU project ASTARTE aims at developing a higher level of tsunami hazard assessment in the North East Atlantic, Mediterranean and Connected seas (NEAM) region by a combination of field work, experimental work, numerical modeling and technical development. The project is a cooperative work of 26 institutes from 16 countries and links together the description of past tsunamigenic events, the identification and characterization of tsunami sources, the calculation of the impact of such events, and the development of adequate resilience and risks mitigation strategies (www.astarte.eu). Within ASTARTE two web-based data bases on Paleotsunami and Mass Transport Deposits in the NEAM areas were created with the purpose to be the future information repositories for tsunami research in Europe.The aim is to integrate every existing official scientific reports and peer reviewed papers on these topics and update on new entries every 6-12 months, hosting information and detailed data, that are crucial e.g for tsunami modeling. A relational database managed by ArcGIS for Desktop 10.x software has been implemented. One of the final goals of the project is the public sharing of the archived datasets through a web-based map service that will allow visualizing, querying, analyzing, and interpreting all datasets. The interactive map service will be hosted by ArcGIS Online and will deploy the cloud capabilities of the portal. Any interested users will be able to access the online GIS resources through any Internet browser or specific apps that run on desktop machines, smartphones, or tablets and will be able to use the analytical tools, key tasks, and workflows of the service.We will present the data bases structure and topics as well as their ArcGIS Online version. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for

  15. Cenomanian to Eocene Stratigraphy of the Jeanne d'Arc Basin Offshore Newfoundland, Canada, with Detailed Examination of Depositional Architecture of the South Mara Member

    Science.gov (United States)

    Karlzen, Kyle

    The South Mara Member in the Jeanne d'Arc Basin offshore Newfoundland, Canada forms significant sand deposits within the post-rift Early Eocene basin. This thesis present through examination of seismic and well data the Cenomanian to Eocene stratigraphy and depositional environments with a detailed examination of transport conduits and depositional architecture of the South Mara Member. South Mara submarine fan deposits are found in the northern basin and deltaic deposits are found in the southern basin. This study proposes north-eastward prograding deltas and mounded pro-delta turbidites were transported through the Cormorant Canyon system onto the peneplain surface on the uplifted Morgiana Anticlinorium. The Cormorant canyons cut into top seals of Lower Cretaceous reservoir units and pose a risk to hydrocarbon exploration of older strata; however, they create hydrocarbon migration pathways between Lower Cretaceous to Eocene reservoir zones.

  16. Online Fan Practices and CALL

    Science.gov (United States)

    Sauro, Shannon

    2017-01-01

    This article provides a narrative overview of research on online fan practices for language and literacy learning, use, and identity work. I begin with an introduction to online fan communities and common fan practices found in these online affinity spaces, the best known of which is fan fiction, fictional writing that reinterprets and remixes the…

  17. The Lower Cretaceous Way Group of northern Chile: An alluvial fan-fan delta complex

    Science.gov (United States)

    Flint, S.; Clemmey, H.; Turner, P.

    1986-01-01

    Alluvial fan sediments of the Lower Cretaceous Coloso Basin in northern Chile were deposited in a half-graben and derived from andesitic volcanics of a former island arc. Transport directions were towards the east, away from the present-day Peru-Chile trench. Grain flow, density modified grain flow and sheetflow processes were responsible for most of the sediment deposition with cohesive debris flows playing only a minor part. An early phase of conglomerate deposition (Coloso Formation) into a restricted basin records the transition from proximal fan facies with abundant grain flows and remobilized screes to mid-fan facies dominated by sheetflows. Stratiform copper mineralization near the top of the lower conglomerates is related to the unroofing of the Jurassic island arc. This mineralization comprises copper sulphide-cemented sands and gravels and formed by the reaction of mineralized detritus with diagenetic and hydrothermal solutions. A later phase of deposition (Lombriz Formation) includes sandstones, siltstones and conglomerates with a source area different from the Coloso Formation. This change in source may be related to strike-slip tectonics as the basin extended. The Lombriz conglomerates pass distally (eastwards) into red sandstones and purple siltstones with thin limestones deposited under marine conditions. This sequence is interpreted as a major fan delta complex. It passes conformably into marine carbonates of the Tableado Formation signifying the complete drowning of the basin in lower Cretaceous times.

  18. Variation of depositional environment during the evolution of deepwater fold-and-thrust belt in the Frontal Ridge area offshore SW Taiwan

    Science.gov (United States)

    Lin, L. F.; Liu, C. S.; Lin, C. C.; Hsu, H. H.; Chang, J. H.; Chen, S. C.; Wang, Y.; Chung, S. H.

    2014-12-01

    The area offshore SW Taiwan is an active margin where the accretionary prism of the Luzon arc-trench system has obliquely overridden the continental margin of the South China Sea (SCS). Located by the Penghu Submarine Canyon, the Frontal Ridge is the westernmost structural relief of the orogenic wedge which is separated from the SCS continental margin by a deformation front. The Penghu submarine canyon, which starts from the China continental shelf and cuts across the fold-and-thrust belt, may plays an important role for transporting orogenic sediments from on shore Taiwan to the deep sea South China Sea basin. In this study, high-resolution seismic data collected in the Frontal Ridge area have been analyzed, a significant variation of stratigraphic architectures with time were identified by detailed analyzing both structural and depositional characteristics. Seismic facies analysis shows that the older parallel strata were eroded and superimposed by a series of lobe-channel-levee complex, interpreted as the fan deposits of the paleo Penghu Submarine Canyon. These deposits were later deformed by a multi-stage frontal thrusting. We propose a model to show how tectonic processes change the depositional environment. During the evolution of fold-and-thrust belt, the slope gradient and sedimentation rate changed. The Frontal Ridge area was at the abyssal plain, and then changed to the continental rise environment. Finally, convergent tectonics changed this area to be part of the orogenic wedge, and frontal fold developed.

  19. Submarine Tailings Disposal (STD—A Review

    Directory of Open Access Journals (Sweden)

    Bernhard Dold

    2014-07-01

    Full Text Available The mining industry is a fundamental industry involved in the development of modern society, but is also the world’s largest waste producer. This role will be enhanced in the future, because ore grades are generally decreasing, thus leading to increases in the waste/metal production ratio. Mine wastes deposited on-land in so-called tailings dams, impoundments or waste-dumps have several associated environmental issues that need to be addressed (e.g., acid mine drainage formation due to sulphide oxidation, geotechnical stability, among others, and social concerns due to land use during mining. The mining industry recognizes these concerns and is searching for waste management alternatives for the future. One option used in the past was the marine shore or shallow submarine deposition of this waste material in some parts of the world. After the occurrence of some severe environmental pollution, today the deposition in the deep sea (under constant reducing conditions is seen as a new, more secure option, due to the general thought that sulphide minerals are geochemically stable under the reduced conditions prevailing in the deep marine environment. This review highlights the mineralogical and geochemical issues (e.g., solubility of sulphides in seawater; reductive dissolution of oxide minerals under reducing conditions, which have to be considered when evaluating whether submarine tailings disposal is a suitable alternative for mine waste.

  20. Experimental alluvial fans: Advances in understanding of fan dynamics and processes

    OpenAIRE

    Clarke, Lucy E

    2015-01-01

    Alluvial fans are depositional systems that develop because of a disparity between the upstream and downstream sediment transport capacity of a system, usually at the base of mountain fronts as rivers emerge from the constrained mountain area onto the plain. They are dynamic landforms that are prone to abrupt changes on a geomorphological (decades to centuries) time scale, while also being long-term deposition features that preserve sedimentary strata and are sensitive indictors of environmen...

  1. Dynamic and Implications of Football Fans' Club and Fans ...

    African Journals Online (AJOL)

    DrNneka

    /afrrev.v10i4.12. Dynamic and Implications of Football Fans' Club and Fans'. Fanaticism for School Violence Among Tertiary Students in. Lagos, Nigeria. Ayorinde, Samuel Agbonna. Department of Educational Foundations and Administration.

  2. Submarine channel evolution linked to rising salt domes, Gulf of Mexico, USA

    Science.gov (United States)

    Carter, Rachel C.; Gani, M. Royhan; Roesler, Toby; Sarwar, Abu K. M.

    2016-08-01

    An examination of halokinetics and channel evolution together in a deepwater system provides an opportunity to investigate how submarine channel morphology is locally affected by rising salt domes. The study area is located in the northern Gulf of Mexico (GOM), directly off the Louisiana continental slope in a prominent salt dome region. The influence of salt growth on submarine channel evolution is relatively understudied, particularly in the GOM. Utilizing high-resolution 3D seismic and well data and seismic geomorphology techniques, a long-lived (~ 3 Myr) Plio-Pleistocene submarine channel system has been investigated to show a relationship between variable phases of salt motion and planform morphology of preserved submarine channels. Our data suggest that local salt motion acts as a driver for submarine channel evolution. During the late Pliocene, when salt moved upward at a relatively fast rate, channels show distinct entrenchment with narrow channel belts and overall less sinuosity. When salt motion slowed down at the beginning of the Pleistocene, channels aggraded rapidly with preserved levees, and moved toward an equilibrium state with the expansion of channel belt widths. As our results indicate, the rate of salt diapirism exerted a first-order control on channel location and morphology and distribution of reservoir-prone units. This study cautions against readily invoking allogenic factors (e.g., sea level and climate) in explaining changes in submarine channel behavior and associated fan sedimentation, particularly in regions with salt tectonics.

  3. Morphogenesis and Morphometry of Alluvial Fans in the High Atlas Morocco: A Geomorphological Model of the Fans of the Wadi Beni Mhammed, Souss Valley

    Directory of Open Access Journals (Sweden)

    Lahoucine Chakir

    2014-09-01

    Full Text Available Morphosedimentary study of alluvial fans formed by the Wadi Beni Mhammed, on the southern piedmont of the western High-Atlas, has indicated three main generations of deposits. Their ages range from ancient (Plio-Pleistocene to Holocene and recent formations. The first generation, comprising small boundary fans, was deposited prior to lateral migration and subsequent entrenchment of the drainage pattern (the combination of the Wadis Aït Mekhlouf and Ida Ou Merouane. The confluence of these powerful streams gave birth to the principal fan that extends to the Souss valley. The third generation of fans was constructed after the incision of the principal fan, by the re-activation of a high secondary fan that was formed from downstream progradation. The morphological characteristics of the fans, such as their area, shape and gradient, are determined from catchment data and, in particular, from the lithology of their provenance areas, which defines the nature of gravel material, sedimentation processes and, finally, the distribtion of constituent materials. Fan shape also depends on the available accommodation space on the piedmont. The Wadi Beni Mhammed fans are elongated, because they are constrained by the mega fans of Wadis Irguitene and Aoukourta. DOI: http://dx.doi.org/10.3126/ije.v3i3.11090 International Journal of Environment Vol.3(3 2014: 293-311

  4. Fans af Bruce

    DEFF Research Database (Denmark)

    Vaaben, Nana Katrine

    2007-01-01

    Analysen viser, hvordan det samme ritual under en koncert forener og opdeler de fans, der orienterer sig mod Bruce Springsteen. På den ene side forener ritualet hele publikum i en stor fælles "Intimitet for mange" og på den anden side splitter det dem, fordi det bliver tydeligt, hvem der er de ri...

  5. ENERGY STAR Certified Ceiling Fans

    Science.gov (United States)

    Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Ceiling Fans that are effective as of April 1, 2012. A detailed listing of key efficiency criteria are available at http://www.energystar.gov/index.cfm?c=ceiling_fans.pr_crit_ceiling_fans

  6. Quantitative reconstruction of late Holocene surface evolution on an alpine debris-flow fan

    Science.gov (United States)

    Schürch, Peter; Densmore, Alexander L.; Ivy-Ochs, Susan; Rosser, Nick J.; Kober, Florian; Schlunegger, Fritz; McArdell, Brian; Alfimov, Vasili

    2016-12-01

    Debris-flow fans form a ubiquitous record of past debris-flow activity in mountainous areas, and may be useful for inferring past flow characteristics and consequent future hazard. Extracting information on past debris flows from fan records, however, requires an understanding of debris-flow deposition and fan surface evolution; field-scale studies of these processes have been very limited. In this paper, we document the patterns and timing of debris-flow deposition on the surface of the large and exceptionally active Illgraben fan in southwestern Switzerland. We use terrain analysis, radiocarbon dating of sediment fill in the Illgraben catchment, and cosmogenic 10Be and 36Cl exposure dating of debris-flow deposits on the fan to constrain the temporal evolution of the sediment routing system in the catchment and on the fan during the past 3200 years. We show that the fan surface preserves a set of debris-flow lobes that were predominantly deposited after the occurrence of a large rock avalanche near the fan apex at about 3200 years ago. This rock avalanche shifted the apex of the fan and impounded sediment within the Illgraben catchment. Subsequent evolution of the fan surface has been governed by both lateral and radial shifts in the active depositional lobe, revealed by the cosmogenic radionuclide dates and by cross-cutting geometrical relationships on the fan surface. This pattern of frequent avulsion and fan surface occupation provides field-scale evidence of the type of large-scale compensatory behavior observed in experimental sediment routing systems.

  7. Submarine landslides on the north continental slope of the South China Sea

    Science.gov (United States)

    Wang, Weiwei; Wang, Dawei; Wu, Shiguo; Völker, David; Zeng, Hongliu; Cai, Guanqiang; Li, Qingping

    2018-02-01

    Recent and paleo-submarine landslides are widely distributed within strata in deep-water areas along continental slopes, uplifts, and carbonate platforms on the north continental margin of the South China Sea (SCS). In this paper, high-resolution 3D seismic data and multibeam data based on seismic sedimentology and geomorphology are employed to assist in identifying submarine landslides. In addition, deposition models are proposed that are based on specific geological structures and features, and which illustrate the local stress field over entire submarine landslides in deep-water areas of the SCS. The SCS is one of the largest fluvial sediment sinks in enclosed or semi-enclosed marginal seas worldwide. It therefore provides a set of preconditions for the formation of submarine landslides, including rapid sediment accumulation, formation of gas hydrates, and fluid overpressure. A new concept involving temporal and spatial analyses is tested to construct a relationship between submarine landslides and different time scale trigger mechanisms, and three mechanisms are discussed in the context of spatial scale and temporal frequency: evolution of slope gradient and overpressure, global environmental changes, and tectonic events. Submarine landslides that are triggered by tectonic events are the largest but occur less frequently, while submarine landslides triggered by the combination of slope gradient and over-pressure evolution are the smallest but most frequently occurring events. In summary, analysis shows that the formation of submarine landslides is a complex process involving the operation of different factors on various time scales.

  8. Centrifugal fans: Similarity, scaling laws, and fan performance

    Science.gov (United States)

    Sardar, Asad Mohammad

    Centrifugal fans are rotodynamic machines used for moving air continuously against moderate pressures through ventilation and air conditioning systems. There are five major topics presented in this thesis: (1) analysis of the fan scaling laws and consequences of dynamic similarity on modelling; (2) detailed flow visualization studies (in water) covering the flow path starting at the fan blade exit to the evaporator core of an actual HVAC fan scroll-diffuser module; (3) mean velocity and turbulence intensity measurements (flow field studies) at the inlet and outlet of large scale blower; (4) fan installation effects on overall fan performance and evaluation of fan testing methods; (5) two point coherence and spectral measurements conducted on an actual HVAC fan module for flow structure identification of possible aeroacoustic noise sources. A major objective of the study was to identity flow structures within the HVAC module that are responsible for noise and in particular "rumble noise" generation. Possible mechanisms for the generation of flow induced noise in the automotive HVAC fan module are also investigated. It is demonstrated that different modes of HVAC operation represent very different internal flow characteristics. This has implications on both fan HVAC airflow performance and noise characteristics. It is demonstrated from principles of complete dynamic similarity that fan scaling laws require that Reynolds, number matching is a necessary condition for developing scale model fans or fan test facilities. The physical basis for the fan scaling laws derived was established from both pure dimensional analysis and also from the fundamental equations of fluid motion. Fan performance was measured in a three times scale model (large scale blower) in air of an actual forward curved automotive HVAC blower. Different fan testing methods (based on AMCA fan test codes) were compared on the basis of static pressure measurements. Also, the flow through an actual HVAC

  9. Development and maintenance of a telescoping debris flow fan in response to human-induced fan surface channelization, Chalk Creek Valley Natural Debris Flow Laboratory, Colorado, USA

    Science.gov (United States)

    Wasklewicz, T.; Scheinert, C.

    2016-01-01

    Channel change has been a constant theme throughout William L. Graf's research career. Graf's work has examined channel changes in the context of natural environmental fluctuations, but more often has focused on quantifying channel change in the context of anthropogenic modifications. Here, we consider how channelization of a debris flows along a bajada has perpetuated and sustained the development of 'telescoping' alluvial fan. Two-dimensional debris-flow modeling shows the importance of the deeply entrenched channelized flow in the development of a telescoping alluvial fan. GIS analyses of repeat (five different debris flows), high-resolution (5 cm) digital elevation models (DEMs) generated from repeat terrestrial laser scanning (TLS) data elucidate sediment and topographic dynamics of the new telescoping portion of the alluvial fan (the embryonic fan). Flow constriction from channelization helps to perpetuate debris-flow runout and to maintain the embryonic fan and telescoping nature of the alluvial fan complex. Embryonic fan development, in response to five debris flows, proceeds with a major portion of the flows depositing on the southern portion of the embryonic fan. The third through the fifth debris flows also begin to shift some deposition to the northern portion of the embryonic. The transfer of sediment from a higher portion of the embryonic fan to a lower portion continues currently on the embryonic fan. While channelized flow has been shown to be critical to the maintenance of the telescoping fan, the flow constriction has led to higher than background levels of sediment deposition in Chalk Creek, a tributary of the Arkansas River. A majority of the sediment from each debris flow is incorporated into Chalk Creek as opposed to being stored on the embryonic fan.

  10. SCICEX: Submarine Arctic Science Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  11. The Submarine, 1776-1918

    National Research Council Canada - National Science Library

    Uhlig, Frank

    2004-01-01

    When, on 11 April 1900, the U.S. Navy thought the Holland, named for its designer, that little submarine joined a fleet consisting of two armored cruisers, six monitors, seven first and second-class battleships, and seventeen each...

  12. Football - Feminisation - Fans

    DEFF Research Database (Denmark)

    Mintert, Svenja-Maria

    Football has long time been considered as a genuine masculine domain. However, in the current football culture, the dualism of masculinity and femaleness is in progress. More and more women consume football which is in many countries considered the most popular sport, not only in Scandinavia where...... the number of female fans in football has grown over the past years. A national sense of community, emotion and passion for the game is in particular reached during the international tournaments at live football spectacles and many female fans cheer and sing for ‘their’ team with the utmost conviction. Yet......, the combination ‘women and football’ is still adhered to certain scepticism. Objective The overall objective of this Ph.D. thesis is to contribute to the body of knowledge associated with the distinct aspects of women’s football, female fandom and gender identities in European football drawing upon various...

  13. Football fan loyalty and the fan conversion experience

    OpenAIRE

    Richardson, Brendan

    2011-01-01

    Paper delivered at Norwich Business School, University of East Anglia, as part of NBS Seminar Series The phenomenon of football fan loyalty has been of conceptual interest to scholars for a considerable period of time. However, the question of how fan loyalty emerges in the first place still eludes us. Also of interest is the complex manner in which this loyalty manifests itself. Fan loyalty to a team does not always extend itself to loyalty towards a team's owners, or express itself throu...

  14. Submarine Information Organization and Prioritization and Submarine Officer of the Deck Experience

    Science.gov (United States)

    2004-07-12

    The Submarine Review, 58-64. Shobe, K. (2002, May). Information organization and modeling of the submarine officer of the deck and sonar operator...Technical Report 01Oct00 - 31Sep02 SUBMARINE INFORMATION ORGANIZATION AND PRIORITIZATION AND SUBMARINE OFFICER OF THE DECK EXPERIENCE 51001 1) Katharine K

  15. Observational Analysis of Coronal Fans

    Science.gov (United States)

    Talpeanu, D.-C.; Rachmeler, L; Mierla, Marilena

    2017-01-01

    Coronal fans (see Figure 1) are bright observational structures that extend to large distances above the solar surface and can easily be seen in EUV (174 angstrom) above the limb. They have a very long lifetime and can live up to several Carrington rotations (CR), remaining relatively stationary for many months. Note that they are not off-limb manifestation of similarly-named active region fans. The solar conditions required to create coronal fans are not well understood. The goal of this research was to find as many associations as possible of coronal fans with other solar features and to gain a better understanding of these structures. Therefore, we analyzed many fans and created an overview of their properties. We present the results of this statistical analysis and also a case study on the longest living fan.

  16. Enhancing Submarine Operational Relevance: A Leadership Challenge

    National Research Council Canada - National Science Library

    Daigle, Jr, Michael J

    2008-01-01

    .... This vision of submarine operations must change. As the military continues to shift to operations focused on joint capabilities, the submarine force must break from the closed, protective, and risk averse culture of its past and push forward...

  17. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    The occurrence of submarine silicic volcanics is rare at the mid-oceanic ridges, abyssal depths, seamounts and fracture zones. Hydrothermal processes are active in submarine silicic environments and are associated with host ores of Cu, Au, Ag, Pb...

  18. Autogenic dynamics of alluvial fans in endorheic basins: Outcrop examples and stratigraphic significance

    NARCIS (Netherlands)

    Ventra, D.|info:eu-repo/dai/nl/304823708; Nichols, G.J.

    2014-01-01

    Alluvial fans are relatively simple depositional systems, due to the direct coupling of sediment sources and adjacent accumulation areas. Nonetheless, general models of alluvial-fan evolution and stratigraphy remain elusive, due to the great sensitivity of such systems to allogenic controls and

  19. 75 FR 79952 - Airworthiness Directives; DASSAULT AVIATION Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN...

    Science.gov (United States)

    2010-12-21

    ... Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN JET FALCON SERIES C, D, E, F, and G Airplanes...) DASSAULT AVIATION Model Falcon 10 airplanes, Model FAN JET FALCON, FAN JET FALCON SERIES C, D, E, F, and G..., FAN JET FALCON SERIES 21-31-10, dated October 2008..... Dassault Fan Jet Falcon C, D, E, F, and G...

  20. Distal turbidite fan/lobe succession of the Late Oligocene Zuberec Fm. – architecture and hierarchy (Central Western Carpathians, Orava–Podhale basin

    Directory of Open Access Journals (Sweden)

    Starek Dušan

    2017-08-01

    Full Text Available A part of the Upper Oligocene sand-rich turbidite systems of the Central Carpathian Basin is represented by the Zuberec Formation. Sand/mud-mixed deposits of this formation are well exposed in the northern part of the basin, allowing us to interpret the turbidite succession as terminal lobe deposits of a submarine fan. This interpretation is based on the discrimination of three facies associations that are comparable to different components of distributive lobe deposits in deep-water fan systems. They correspond to the lobe off-axis, lobe fringe and lobe distal fringe depositional subenvironments, respectively. The inferences about the depositional paleoenvironment based on sedimentological observations are verified by statistical analyses. The bed-thickness frequency distributions and vertical organization of the facies associations show cyclic trends at different hierarchical levels that enable us to reconstruct architectural elements of a turbidite fan. First, small-scale trends correspond with shift in the lobe element centroid between successive elements. Differences in the distribution and frequency of sandstone bed thicknesses as well as differences in the shape of bed-thickness frequency distributions between individual facies associations reflect a gradual fining and thinning in a down-dip direction. Second, meso-scale trends are identified within lobes and they generally correspond to the significant periodicity identified by the time series analysis of the bed thicknesses. The meso-scale trends demonstrate shifts in the position of the lobe centroid within the lobe system. Both types of trends have a character of a compensational stacking pattern and could be linked to autogenic processes. Third, a largescale trend documented by generally thickening-upward stacking pattern of beds, accompanied by a general increase of the sandstones/mudstones ratio and by a gradual change of percentage of individual facies, could be comparable to lobe

  1. North American Submarine Cable Association (NASCA) Submarine Cables

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data show the locations of in-service and out-of-service submarine cables that are owned by members of NASCA and located in U.S. territorial waters. More...

  2. Effects of weathering and lithology on the quality of aggregates in the alluvial fans of Northeast Rivand, Sabzevar, Iran

    Science.gov (United States)

    Bahrami, Shahram; Fatemi Aghda, Seyed Mahmoud; Bahrami, Kazem; Motamedi Rad, Mohammad; Poorhashemi, Sima

    2015-07-01

    Alluvial fans as depositional landforms can be considered as potential sources of aggregates. As the age of alluvial fans increases, their constituent sediments are exposed to longer periods of weathering and increased mineral alteration, resulting in a decrease in aggregate quality. In this study, physical properties and point load tests were used to assess the aggregate quality on three alluvial fan surfaces (relict, old and young) in the northeastern part of Rivand village in west of Sabzevar, Northeast Iran. Differentiating young from old and relict fans was carried out based on geomorphic criteria such as weathering features, fan surface morphology and drainage pattern. The young alluvial fan is characterized by sub-rounded and unvarnished clasts, distributary drainage patterns and a relatively flat surface, whereas old and relict fans are characterized by incised and rough surfaces, tributary drainage pattern and highly weathered and varnished clasts due to their long-term exposure to weathering. Due to a range of rock types occurring across each fan surface, lithological studies were performed to eliminate the effect of lithology on aggregate quality. A total of 18 rock types comprising comparable lithologies were sampled from each of the three alluvial fans. Results show that, in almost all 18 rock types, the point load test values increases from relict to young fans whereas porosity and percentage of water absorption decrease, implying that aggregate quality decreases with time as a function of duration of exposure to weathering. Also, the strength of aggregates in all three fans decreases from the fan apex to the fan toe. Data show that micaceous, intrusive igneous rocks, tuffs with high porosity and fine-grained extrusive igneous rocks with some porosity are more sensitive to physical weathering, and therefore have lower strength, particularly on the relict and old fans. Overall, variations in aggregate strength on these fans can be attributed to the

  3. Fan Cart: The Next Generation

    Science.gov (United States)

    Lamore, Brian

    2016-01-01

    For years the fan cart has provided physics students with an excellent resource for exploring fundamental mechanics concepts such as acceleration, Newton's laws, impulse, momentum, work-energy, and energy conversions. "The Physics Teacher" has even seen some excellent do-it-yourself (DIY) fan carts and activities. If you are interested…

  4. Submarine geothermal resources

    Science.gov (United States)

    Williams, D.L.

    1976-01-01

    Approximately 20% of the earth's heat loss (or 2 ?? 1012 cal/s) is released through 1% of the earth's surface area and takes the form of hydrothermal discharge from young (Pleistocene or younger) rocks adjacent to active seafloor-spreading centers and submarine volcanic areas. This amount is roughly equivalent to man's present gross energy consumption rate. A sub-seafloor geothermal reservoir, to be exploitable under future economic conditions, will have to be hot, porous, permeable, large, shallow, and near an energy-deficient, populated land mass. Furthermore, the energy must be recoverable using technology achievable at a competitive cost and numerous environmental, legal and institutional problems will have to be overcome. The highest-temperature reservoirs should be found adjacent to the zones of the seafloor extension or volcanism that are subject to high sedimentation rates. The relatively impermeable sediments reduce hydrothermal-discharge flow rates, forcing the heat to be either conducted away or released by high-temperature fluids, both of which lead to reservoir temperatures that can exceed 300??C. There is evidence that the oceanic crust is quite permeable and porous and that it was amenable to deep (3-5 km) penetration by seawater at least some time in the early stages of its evolution. Most of the heat escapes far from land, but there are notable exceptions. For example, in parts of the Gulf of California, thermal gradients in the bottom sediments exceed 1??C/m. In the coastal areas of the Gulf of California, where electricity and fresh water are at a premium, this potential resource lies in shallow water (< 200 m) and within sight of land. Other interesting areas include the Sea of Japan, the Sea of Okhotsk and the Andaman Sea along the margins of the western Pacific, the Tyrrhenian Sea west of Italy, and the southern California borderland and west flank of the Juan de Fuca Ridge off the west coast of the United States. Many questions remain to be

  5. Combined velocity and depth mapping on developing laboratory alluvial fans

    Science.gov (United States)

    Hamilton, P.; Strom, K. B.; Hoyal, D. C.

    2011-12-01

    Large-scale particle image velocimetry (LSPIV) is a nonintrusive method for measuring free-surface velocities using tracer patterns in a sequence of images. This method has been applied in both natural rivers and large-scale hydraulic models (Muste et al., 2008). Here the method is used to map channel and sheet flow velocity during the development of laboratory-scale alluvial fans. Measuring the time and space varying hydraulics on laboratory fans by traditional methods is not practical since flows are quite shallow (~1 cm). Additionally, the highly dynamic environment makes positioning of traditional probe-type instruments difficult and their physical presence could alter autogenic fan evolution. These difficulties can be overcome by using particle image velocimetry techniques. Furthermore, images collected in the LSPIV method can be used to extract flow depth using a calibrated dye-intensity method (Gran and Paola, 2001). This allows for simultaneous measurement of flow velocity and depth everywhere over the fan at any point in time. To validate the method, a set of controlled small-scale experiments were run for depths ranging from 0.2-1.5 cm and velocities from 10-100 cm/sec. Comparison of the LSPIV and dye-intensity method measurements to the known values indicated that the methodology was able to accurately capture simultaneous flow velocity and depth in this range of conditions, i.e., those encountered during the development of laboratory-scale alluvial fans and streams. The method is then used to map the hydraulics associated with various fan processes during development as demonstrated in figure 1. The ability to measure hydraulic properties during fan development is important since physical models provide an arena for observing the time evolution and morphodynamic feedback in depositional systems such as alluvial fans.

  6. Submarine canyons off Madras Coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Submarine canyons off the coast of Madras, Tamil Nadu, India were studied during cruise of @iINS Kistna@@ as part of the IIOE programme They consist of hill-like projections and V-shaped valleys Their other features are also reported...

  7. Early to Late Pleistocene history of debris-flow fan evolution in western Death Valley (California) using cosmogenic 10Be and 26Al

    Science.gov (United States)

    Dühnforth, Miriam; Densmore, Alexander L.; Ivy-Ochs, Susan; Allen, Philip; Kubik, Peter W.

    2017-03-01

    Debris-flow fans with depositional records over several 105 years may be useful archives for the understanding of fan construction by debris flows and post-depositional surface modification over long timescales. Reading these archives, however, requires that we establish the temporal and spatial pattern of debris-flow activity over time. We used a combination of geomorphic mapping of fan surface characteristics, digital topographic analysis, and cosmogenic radionuclide dating using 10Be and 26Al to study the evolution of the Warm Springs fan on the west side of southern Death Valley, California. The 10Be concentrations yield dates that vary from 989 ± 43 to 595 ± 17 ka on the proximal fan and between 369 ± 13 and 125 ± 5 ka on distal fan surfaces. The interpretation of these results as true depositional ages though is complicated by high inheritance with a minimum of 65 ka measured at the catchment outlet and of at least 125 ka at the distal fan. Results from the 26Al measurements suggest that most sample locations on the fan surfaces underwent simple exposure and were not affected by complex histories of burial and re-exposure. This implies that Warm Springs fan is a relatively stable landform that underwent several 105 years of fan aggradation before fan head incision caused abandonment of the proximal and central fan surfaces and deposition continued on a younger unit at the distal fan. We show that the primary depositional debris-flow morphology is eliminated over a time scale of less than 105 years, which prevents the delineation of individual debris flows as well as the precise reconstruction of lateral shifts in deposition as we find it on younger debris-flow fans. Secondary post-depositional processes control subsequent evolution of surface morphology with the dissection of planar surfaces while smoothing of convex-up interfluves between incised channels continues through time.

  8. ENERGY STAR Certified Ceiling Fans

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Ceiling Fans that are effective as of April 1,...

  9. Stranger than fiction: Fan identity in cosplay

    Directory of Open Access Journals (Sweden)

    Nicolle Lamerichs

    2011-09-01

    Full Text Available Academic accounts of fan cultures usually focus on creative practices such as fan fiction, fan videos, and fan art. Through these practices, fans, as an active audience, closely interpret existing texts and rework them with texts of their own. A practice scarcely examined is cosplay ("costume play", in which fans produce their own costumes inspired by fictional characters. Cosplay is a form of appropriation that transforms and actualizes an existing story in close connection to the fan community and the fan's own identity. I provide analytical insights into this fan practice, focusing on how it influences the subject. Cosplay is understood as a performative activity and analyzed through Judith Butler's concept of performativity. I specifically focus on boundaries between the body and dress, and on those between reality and fiction. I aim to show that cosplay emphasizes the personal enactment of a narrative, thereby offering new perspectives on fan identity.

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

    Science.gov (United States)

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

    2017-04-01

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

  11. SCICEX: Submarine Arctic Science Program, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Submarine Arctic Science Program, SCICEX, is a federal interagency collaboration among the operational Navy, research agencies, and the marine research community...

  12. Fan beam intensity modulated proton therapy

    Science.gov (United States)

    Hill, Patrick M.

    A fan beam proton therapy is developed which delivers intensity modulated proton therapy using distal edge tracking. The system may be retrofit onto existing proton therapy gantries without alterations to infrastructure in order to improve treatments through intensity modulation. A novel range and intensity modulation system is designed using acrylic leaves that are inserted or retracted from subsections of the fan beam. Leaf thicknesses are chosen in a base-2 system and motivated in a binary manner. Dose spots from individual beam channels range between 1 and 5 cm. Integrated collimators attempting to limit crosstalk among beam channels are investigated, but found to be inferior to uncollimated beam channel modulators. A treatment planning system performing data manipulation in MATLAB and dose calculation in MCNPX is developed. Beamlet dose is calculated on patient CT data and a fan beam source is manually defined to produce accurate results. An energy deposition tally follows the CT grid, allowing straightforward registration of dose and image data. Simulations of beam channels assume that a beam channel either delivers dose to a distal edge spot or is intensity modulated. A final calculation is performed separately to determine the deliverable dose accounting for all sources of scatter. Treatment plans investigate the effects that varying system parameters have on dose distributions. Beam channel apertures may be as large as 20 mm because the sharp distal falloff characteristic of proton dose provides sufficient intensity modulation to meet dose objectives, even in the presence of coarse lateral resolution. Dose conformity suffers only when treatments are delivered from less than 10 angles. Jaw widths of 1--2 cm produce comparable dose distributions, but a jaw width of 4 cm produces unacceptable target coverage when maintaining critical structure avoidance. Treatment time for a prostate delivery is estimated to be on the order of 10 minutes. Neutron production

  13. Frontal and Lateral Submarine Lobe Fringes: Comparing Sedimentary Facies, Architecture and Flow Processes

    NARCIS (Netherlands)

    Spychala, Yvonne T.; Hodgson, David M.; Prélat, Amandine; Kane, Ian A.; Flint, Stephen S.; Mountney, Nigel P.

    2017-01-01

    Submarine lobe-fringe deposits form heterolithic successions that may include a high proportion of hybrid beds. The identification of lobe-fringe successions aids interpretation of paleogeographic setting and the degree of basin confinement. Here, for the first time, the sedimentological and

  14. Submarines, spacecraft and exhaled breath.

    Science.gov (United States)

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another

  15. Tsunami Generated by a Two-Phase Submarine Debris Flow

    Science.gov (United States)

    Pudasaini, S. P.

    2012-04-01

    The general two-phase debris flow model proposed by Pudasaini (2011) is employed to study subaerial and submarine debris flows, and the tsunami generated by the debris impact at lakes and oceans. The model includes several essential physical aspects, including Mohr-Coulomb plasticity for the solid stress, while the fluid stress is modelled as a solid volume fraction gradient enhanced non-Newtonian viscous stress. The generalized interfacial momentum transfer includes the viscous drag, buoyancy, and the virtual mass. The generalized drag covers both the solid-like and fluid-like contributions, and can be applied to linear to quadratic drags. Strong couplings exist between the solid and the fluid momentum transfer. The advantage of the real two-phase debris flow model over classical single-phase or quasi-two-phase models is that by considering the solid (and/or the fluid) volume fraction appropriately, the initial mass can be divided into several (even mutually disjoint) parts; a dry (landslide or rock slide), a fluid (water or muddy water; e.g., dams, rivers), and a general debris mixture material as needed in real flow simulations. This offers a unique and innovative opportunity within a single framework to simultaneously simulate (a) the sliding debris (or landslide), (b) the water lake or ocean, (c) the debris impact at the lake or ocean, (d) tsunami generation and propagation, (e) mixing and separation between the solid and the fluid phases, and (f) sediment transport and deposition process in the bathymetric surface. The new model is applied to two-phase subaerial and submarine debris flows. Benchmark numerical simulations reveal that the dynamics of the debris impact induced tsunamis are fundamentally different than the tsunami generated by pure rock avalanche and landslides. Special attention is paid to study the basic features of the debris impact to the mountain lakes or oceans. This includes the generation, amplification and propagation of the multiple

  16. Eocene slope and basin depositional systems in the Santos Basin, SP, Brazil; Sistemas deposicionais de talude e de bacia no Eoceno da Bacia de Santos

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Jobel Lourenco Pinheiro [PETROBRAS, Santos, SP (Brazil). Unidade de Negocio de Exploracao. Polo Norte]. E-mail: jobel@petrobras.com.br; Carminatti, Mario

    2004-05-01

    The study of deposits originated by sedimentary gravity flows in continental margin basins has systematically underrated the local stratigraphic context. In consequence, some types of terrigenous depositional systems, from both shallow and deep waters, are improperly described as turbidity deposits. In the same way, sand/shale maps have been elaborated for sedimentary gravity flow deposits without considering their depositional environment. This fact provides incorrect information about reservoir behaviour and seal rock distribution, with possible prejudice to geological interpretation for petroleum exploration and production. Sedimentary gravity flows form the main deposits in the slope-basin of the lower-middle Eocene depositional sequences to the N of the Santos Basin. The objective of this study is the stratigraphic characterization of the the main elements of the depositional systems that occur in the Eocene section of the study area on the basis of sequence stratigraphy. As a result, two distinct systems of terrigenous deposits formed by sedimentary gravity flows on a single 3 rd order depositional sequence are defined: A Sandy System and a Muddy System. The Sandy System, deposited during periods of sea level fall, was formed by autochthonous sediments of gravity flows originated by fluvial floods. It is characterized by the following depositional elements: fluvial channels, canyons, submarine channels and basin sandy fans. These sandstone reservoirs have generally high porosity and permeability. A Muddy System, deposited under high-stand sea level conditions, and formed by gravity flows caused by autochthonous sediment slides, can be recognized by the following depositional elements: shelf-margin delta, steep erosional surfaces, accretion wedges and chaotic matrix-supported conglomerate beds. Such conglomerate beds have low permeability and form poor quality reservoirs. The hemi pelagic sediments of the late transgressive sea level phase, when preserved from

  17. Morphometric Characterization and Classification of Alluvial Fans in Eastern Oman

    Science.gov (United States)

    Leuschner, Annette; Mattern, Frank; van Gasselt, Stephan

    2015-04-01

    Morphologic characteristics of alluvial fans are a product of fluvial erosion, transportation and deposition. Consequently, fans have been described and defined on the basis of their shape, their composition, conditions and processes under which they from, their so-called "controlling factors", and their geomorphic and tectonic settings. The aim of our study is to reconstruct the morphologic evolution and to relate it to past and present climate conditions. In order to achieve this, we first characterize alluvial fans based on their climatic settings and conditions and classify them accordingly using satellite image data and digital elevation models. For mapping of different alluvial fan bodies multispectral images of the Landsat Enhanced Thematic Mapper (ETM+) with a scale of 15-30 m/px were utilized. For the detection of morphometric parameters as input data for subsequent hydrological studies digital terrain model data of the Shuttle Radar Topography Mission (SRTM) and the ASTER GDEM with a scale of 90 m/px and 30m, respectively, were used. Using these datasets morphological characteristics, such as sizes of drainage basins, transport areas and areas of deposition derived from spatial semi-automatic analysis, have been computed. The area of Muscat at the Oman Mountains has been selected as a study area because of its size, accessibility and climate conditions and it is considered well-suited for studying the development of alluvial fans and their controlling factors. The Oman Mountains are well-known for the world's largest intact and best exposed obducted ophiolite complex, the Semail Ophiolite. They are today subjected to a mild desert climate (Bwh), influenced by the Indian Ocean but they have experienced extensive pluvial periods in the geologic past. Formation of alluvial fans was, therefore, likely triggered by the interplay of increased sediment production caused by high rainfalls with enhanced erosion of hillslopes and transport rates during pluvial

  18. Football – Feminisation – Fans

    DEFF Research Database (Denmark)

    Mintert, Svenja-Maria

    Football has long time been considered as a genuine masculine domain. However, in the current football culture, the dualism of masculinity and femaleness is in progress. More and more women consume football which is in many countries considered the most popular sport, not only in Scandinavia where...... the number of female fans in football has grown over the past years. A national sense of community, emotion and passion for the game is in particular reached during the international tournaments at live football spectacles and many female fans cheer and sing for ‘their’ team with the utmost conviction. Yet...... and interpretation of the sport. Research question The overarching research question centres upon how and to what extent the role of gender in football and fan cultures is manifested with a particular focus on gender-specific patterns of crosscultural communication and identification. Methods and Approach...

  19. Boulder emplacement and remobilisation by cyclone and submarine landslide tsunami waves near Suva City, Fiji

    Science.gov (United States)

    Lau, A. Y. Annie; Terry, James P.; Ziegler, Alan; Pratap, Arti; Harris, Daniel

    2018-02-01

    The characteristics of a reef-top boulder field created by a local submarine landslide tsunami are presented for the first time. Our examination of large reef-derived boulders deposited by the 1953 tsunami near Suva City, Fiji, revealed that shorter-than-normal-period tsunami waves generated by submarine landslides can create a boulder field resembling a storm boulder field due to relatively short boulder transport distances. The boulder-inferred 1953 tsunami flow velocity is estimated at over 9 m s- 1 at the reef edge. Subsequent events, for example Cyclone Kina (1993), appear to have remobilised some large boulders. While prior research has demonstrated headward retreat of Suva Canyon in response to the repeated occurrence of earthquakes over the past few millennia, our results highlight the lingering vulnerability of the Fijian coastlines to high-energy waves generated both in the presence (tsunami) and absence (storm) of submarine failures and/or earthquakes. To explain the age discrepancies of U-Th dated coral comprising the deposited boulders, we introduce a conceptual model showing the role of repeated episodes of tsunamigenic submarine landslides in removing reef front sections through collapse. Subsequent high-energy wave events transport boulders from exposed older sections of the reef front onto the reef where they are deposited as 'new' boulders, alongside freshly detached sections of the living reef. In similar situations where anachronistic deposits complicate the deposition signal, age-dating of the coral boulders should not be used as a proxy for determining the timing of the submarine landslides or the tsunamis that generated them.

  20. Oceanographic studies supporting the assessment of deep-sea disposal of defueled decommissioned nuclear submarines

    Science.gov (United States)

    Ross Heath, G.; Rea, David K.; Ness, Gordon; Dale Pillsbury, R.; Beasley, Thomas M.; Lopez, Carlos; Talbert, Daniel M.

    1984-12-01

    Based on criteria developed by the international Atomic Energy Agency (IAEA), potential disposal sites for defueled, decommissioned nuclear submarines appear to exist in deep water south of the Mendocino Fracture Zone within 200 nautical miles of the United States Oceanographic measurements in the water column and at the sea floor in a study area (W-N) at 39 5°N, 127 5°W will allow the operational and radiological consequences of deep-sea disposal to be compared with land burial of old submarines. The W-N studies also are yielding new data that will provide insights to the deposition and early diagenesis of distal hemipelagic sediments

  1. Vacuum Cleaner Fan Being Improved

    Science.gov (United States)

    Tweedt, Daniel L.

    1997-01-01

    As part of the technology utilization program at the NASA Lewis Research Center, efforts are underway to transfer aerospace technologies to new areas of practical application. One such effort involves using advanced computational fluid dynamics (CFD) codes for turbomachinery to analyze the internal fluid dynamics of low-speed fans and blowers. This year, the Kirby Company in Cleveland, Ohio, approached NASA with a request for technologies that could help them improve their vacuum cleaners. Of particular interest to Kirby is the high-frequency blade-passing noise generation of their vacuum cleaner fan at low airflow rates.

  2. Submarine landslides of the Southern California Borderland

    Science.gov (United States)

    Lee, H.J.; Greene, H. Gary; Edwards, B.D.; Fisher, M.A.; Normark, W.R.

    2009-01-01

    Conventional bathymetry, sidescan-sonar and seismic-reflection data, and recent, multibeam surveys of large parts of the Southern California Borderland disclose the presence of numerous submarine landslides. Most of these features are fairly small, with lateral dimensions less than ??2 km. In areas where multibeam surveys are available, only two large landslide complexes were identified on the mainland slope- Goleta slide in Santa Barbara Channel and Palos Verdes debris avalanche on the San Pedro Escarpment south of Palos Verdes Peninsula. Both of these complexes indicate repeated recurrences of catastrophic slope failure. Recurrence intervals are not well constrained but appear to be in the range of 7500 years for the Goleta slide. The most recent major activity of the Palos Verdes debris avalanche occurred roughly 7500 years ago. A small failure deposit in Santa Barbara Channel, the Gaviota mudflow, was perhaps caused by an 1812 earthquake. Most landslides in this region are probably triggered by earthquakes, although the larger failures were likely conditioned by other factors, such as oversteepening, development of shelf-edge deltas, and high fluid pressures. If a subsequent future landslide were to occur in the area of these large landslide complexes, a tsunami would probably result. Runup distances of 10 m over a 30-km-long stretch of the Santa Barbara coastline are predicted for a recurrence of the Goleta slide, and a runup of 3 m over a comparable stretch of the Los Angeles coastline is modeled for the Palos Verdes debris avalanche. ?? 2009 The Geological Society of America.

  3. Dynamic and Implications of Football Fans' Club and Fans ...

    African Journals Online (AJOL)

    DrNneka

    Sports administrators, players and fans are expected to promote peace and spirit of goodwill and not fanaticism in sporting activities. This idea of 'game for peace and not .... what Henri Tajfel, a social Psychologist, referred to as In –group Bias. .... significantly vary among tertiary students in Lagos on the basis of gender.

  4. Reconstruction of the sediment transport conditions in the Urumqi alluvial fan (northeastern Tian Shan, China)

    OpenAIRE

    Guerit, Laure; BARRIER, Laurie; Métivier, F; Liu, Youcun; Narteau, Clement; Lajeunesse, Eric; Gayer, Eric; Meunier, Patrick; Baisheng, Ye

    2011-01-01

    International audience; Alluvial fans must contain information about the physical parameters of palaeo-rivers that built them. In particular, their grain-size evolution is partly related to water discharge and granulometry of the sediment supply. However, the temporal framework of deposits could also influence this grain size evolution. In order to discriminate the respective influence of the short-and long-term sedimentation dynamics on the grain-size organization of alluvial fans, we used a...

  5. Early diagenesis in the Congo deep-sea fan sediments dominated by massive terrigenous deposits: Part I - Oxygen consumption and organic carbon mineralization using a micro-electrode approach

    Science.gov (United States)

    Pozzato, Lara; Cathalot, Cécile; Berrached, Chabha; Toussaint, Flora; Stetten, Elsa; Caprais, Jean-Claude; Pastor, Lucie; Olu, Karine; Rabouille, Christophe

    2017-08-01

    Organic matter (OM) transfer from the continent to the ocean occurs across margins which constitute a major area of OM recycling and burial. The lobe complex of the Congo deep-sea fan is connected to the river mouth by a canyon and alimented by recurrent turbidity currents, containing a large proportion of labile terrigenous OM and producing high sedimentation rates. These inputs support the development of ecosystems harboring rich assemblages of vesicomyid bivalves and bacterial mats, called Habitats. Here, we present O2 microprofiles and diffusive oxygen uptake rates (DOUs) obtained during the CONGOLOBE project at six sites of this active lobe complex by in situ and on-board methods based on micro-electrode profiling. The dataset is used to determine remineralization rates and study the biogeochemical dynamics of different ecosystems of the lobe area, in order to compare levee and background sediments to the Habitats developed on the flanks of the main turbiditic channel. Levee and background sediments are characterized by significantly higher DOUs than abyssal sediments at 5000 m meters depth (2-5 mmol O2 m-2 d-1versus 1.5-2.5 mmol O2 m-2 d-1) and the Habitats are hotspots of OM remineralization with DOU values ranging between 8 and 40 mmol O2 m-2 d-1. By comparing sites near the active channel to a site located 50 km away, we show that the lobe connection to the main turbiditic channel is vital to the dense benthic communities.

  6. Advance Noise Control Fan II: Test Rig Fan Risk Management Study

    Science.gov (United States)

    Lucero, John

    2013-01-01

    Since 1995 the Advanced Noise Control Fan (ANCF) has significantly contributed to the advancement of the understanding of the physics of fan tonal noise generation. The 9'x15' WT has successfully tested multiple high speed fan designs over the last several decades. This advanced several tone noise reduction concepts to higher TRL and the validation of fan tone noise prediction codes.

  7. ROV Tiburon Investigation of Hawaiian Submarine Canyons

    Science.gov (United States)

    Paull, C. K.; Greene, H. G.; Caress, D. W.; Clague, D. A.; Ussler, W.; Maher, N. M.

    2001-12-01

    MBARI conducted ROV dives around the Hawaiian Islands during an expedition of the R/V Western Flyer and Tiburon in the spring of 2001. Eight ROV dives were made to investigate five major submarine canyons offshore of Oahu, Molokai, and Hawaii in up to 3,434 m water depths. Four of these canyons are located off the windward (northern) side of these islands where onshore canyons are also well developed. Those canyons located offshore of Molokai and Oahu incise the head scars of the giant Nuuanu and Wailai submarine landslides. ROV observations and sediment and rock outcrop sampling were made in these canyons to determine their origin and present-day activity. The fifth canyon investigated is located on the leeward (southern) side of Molokai. The canyons along the windward side expose extensive stratigraphic sections that reveal the history of the islands' formation. In composite, these sections contain marine pillow basalt overlain by a substantial sequence of alternating subaerial lava flows, rounded boulder conglomerates, shallow water carbonates, and hyaloclastites that indicate coastal and marine deposition. These sequences illustrate the accretion and subsequent subsidence of the islands' flanks. These canyons also have morphologically distinct upper and lower sections. The upper reaches of the canyons are incised into the shallow water marine facies and contain broad axial channels through which active sediment transport is occurring. In contrast, the morphology of the lower canyons are strongly influenced by the giant landslides that massively altered the northern flanks of the Hawaiian chain. The lower canyons contain plunge pools and steep headwall scarps that are generally comprised of mechanically competent subaerial lava flows. The presence of multiple plunge pools with differentially eroded head scarps suggests retrogressive erosion (bottom-up process) with headward advancement of the various heads. Undercutting of the headwalls also produce periodic

  8. Deep-water turbidity systems: a review of their elements, sedimentary processes and depositional models. Their characteristics on the Iberian margins; Sistemas turbiditicos de aguas profundas: revision de sus elementos, procesos sedimentarios y modelos deposicionales. Sus caracteristicas en los margenes Ibericos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, M.; Ercilla, G.; Alonso, B.; Estrada, F.; Jane, G.; Mena, A.; Alves, T.; Juan, C.

    2015-07-01

    Turbidity systems or submarine fans are considered the most important clastic accumulations in the deep sea and represent the sediment-transfer system between the hinterland source area and the deep-sea depositional sink. Their deposits contain information about global factors and local factors. Different scales and varying observational methods have contributed to the lack of a unifying terminology. In order to solve this problem several authors have proposed an elemental approach. The main architectural elements defining a turbidity sys- tem are: large-scale erosive features (mass-movements and canyons), channels and channel-fill deposits, over- bank deposits and lobes. The sediment making up these elements is principally from gravity flow deposits, the most widely recognised being the turbidity, and other submarine mass movements. The genesis and character of these elements, as well as the overall geometry of the systems, indicate they are formed by a complex inter- action between global and local factors. Various turbidity-system classifications are found in the literature, the most widely-used being based on grain size and feeder systems. Besides the scientific importance of turbiditic systems, they are predominantly studied because of the economic interest in them, as turbidite sandstones con- stitute important gas and oil reservoirs. Turbidite systems shape the sea floor of the Iberian continental margins and contribute in a large part to their outbuilding and basin in filling. They are hugely variable in size, location within the physiographic domains, style and overall geometry of the architectural elements, as well as sediment composition. The most studied Iberian turbidity fans are in the Mediterranean Sea whereas those of the Atlantic Ocean remain poorly known. (Author)

  9. School Athletics and Fan Aggression

    Science.gov (United States)

    Bryan, Clifford; Horton, Robert

    1976-01-01

    Several hypotheses are developed regarding fans and their behavior based upon a review of the literature. An exploratory study is then described, in which participant observers at a university sports arena observed cases of aggressive behavior among the spectators. Based upon the literature review and the findings of the study, four…

  10. Online Fan Fiction and Critical Media Literacy

    Science.gov (United States)

    Black, Rebecca W.

    2010-01-01

    This article explores English-language-learning (ELL) youths' engagement with popular media through composing and publicly posting stories in an online fan fiction writing space. Fan fiction is a genre that lends itself to critical engagement with media texts as fans repurpose popular media to design their own narratives. Analyses describe how…

  11. Similarities between rivers and submarine channels

    Science.gov (United States)

    Balcerak, Ernie

    2013-02-01

    Scientists have long known that the width and depth of rivers follows a power law relationship with discharge. They have also noticed that submarine channels appear to be similar to terrestrial rivers, but there have not been many systematic comparisons of the relationships between submarine channel morphology and discharge. Konsoer et al. compared the width, depth, and slope of 177 submarine channels to those of 231 river cross sections. They found that submarine channels are up to an order of magnitude wider and deeper than the largest terrestrial rivers, but they exhibit a similar power law relationship between width and depth. For submarine channels that were similar in size to rivers, the authors found that submarine channels tend to be 1 to 2 orders of magnitude steeper than rivers. The authors also inferred values for sediment concentration in the turbidity currents in the channels and combined this with estimated mean flow velocities to look for a relationship between discharge and morphology in the channels. They found that like rivers, the width and depth of the submarine channels follow a power law scaling with discharge. (Journal of Geophysical Research-Earth Surface, doi:10.1029/2012JF002422, 2013)

  12. Scientific Ocean Drilling to Assess Submarine Geohazards along European Margins

    Science.gov (United States)

    Ask, M. V.; Camerlenghi, A.; Kopf, A.; Morgan, J. K.; Ocean DrillingSeismic Hazard, P. E.

    2008-12-01

    Integrated Ocean Drilling Program (IODP) provides technologically top-level drilling vessels and platforms that can be used by scientists to address global scientific problems, including the causes and processes responsible for submarine geohazards. Both IODP and ECORD (the European Consortium for Ocean Research Drilling in collaboration with the European Science Foundation) support scientific initiatives towards submarine geohazards, because the geological record of geohazards can be read and interpreted only through ocean drilling, combined with a broad array of geophysical, geotechnical, and laboratory studies, to identify structures and deposits associated with hazardous phenomena.

  13. Koroška Bela alluvial fan – The result of the catastrophic slope events; (Karavanke Mountains, NW Slovenia

    Directory of Open Access Journals (Sweden)

    Jernej Jež

    2008-12-01

    Full Text Available The Koroška Bela alluvial fan deposits were investigated to determine the genesis of the fan and the source area of sediments. The alluvial fan is composed of a sequence of diamicton layers, and related subaeric sediments that were deposited by multiple mass flow events, in some cases certainly by debris flows. The predominant sources ofsediments are tectonically deformed clastic and partly carbonate Carbonifferous and Permian rocks. In diamictons also pebbles of other rocks from the hinterland are present. These were eroded from the channel of Bela during the mass flow events. We estimate the future debris flow hazard along Bela stream as high.

  14. Heavy mineral sorting as a tool to distinguish depositional characteristics of “in situ” sands from their related injected sands in a Palaeogene submarine Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Moatari Kazerouni, Afsoon; Friis, Henrik; Svendsen, Johan. B

    Postdepositional remoblization and injection of sand are important processes in deep-water clastic systems. Subsurface mobilisation and injection of sand has been recently recognised as a significant control of deep-water sandstone geometry. Kilometre-scale injection complexes have been interpreted...... in the Paleocene Siri Canyon near the Danish Central Graben of the North Sea hydrocarbon province from borehole data. The emplacement of large-scale injection complexes has been commonly attributed in the geological literature to seismic activity and consequent sand liquefaction. However, due to very small...... differences in textural and compositional properties, and the lack of depositional structures of reservoir sands in the Siri Canyon, the distinction between "in situ" and injected or remobilised sands is difficult. Large scale heavy mineral sorting (in 10 m thick units) is observed in several reservoir units...

  15. Self-similar growth of an alluvial fan fed with bimodal sediment

    Science.gov (United States)

    Delorme, Pauline; Voller, Vaughan; Paola, Chris; Devauchelle, Olivier; Lajeunesse, Eric; Barrier, Laurie; Métivier, François

    2016-04-01

    At the outlet of mountain ranges, rivers flow onto flatter lowlands. The associated change of slope causes sediment deposition. As the river is free to move laterally, it builds conical sedimentary structures called alluvial fans. Their location at the interface between erosional and depositional areas makes them valuable sedimentary archives. To decipher these sedimentary records, we need to understand the dynamics of their growth. We carried out a series of experiments to investigate the growth of alluvial fans fed with mixed sediments. The density difference between silica and coal sediments mimics a bimodal grain-size distribution in nature. The sediment and water discharges are constant during an experiment. During the run, we track the evolution of the surface pattern by digital imaging. At the end of each run, we acquire the fan topography using a scanning laser. Finally, we cut a radial cross section to visualize the sedimentary deposit. We observe there is a distinct slope break at the transition that dominates the overall curvature of the fan surface. Based on mass conservation and observations, we propose that this alluvial fan grows in a self-similar way, thus causing the transition between silica and coal deposits to be a straight line. The shape of the experimental transition accords with this prediction.

  16. Aspects of Propeller Developements for a Submarine

    DEFF Research Database (Denmark)

    Andersen, Poul; kappel, Jens Julius; Spangenberg, Eugen

    2009-01-01

    Design and development of propellers for submarines are in some ways different from propellers for surface vessels. The most important demand is low acoustic signature that has priority over propeller efficiency, and the submarine propeller must be optimized with respect to acoustics rather than...... efficiency. Moreover the operating conditions of a submarine propeller are quite different. These aspects are discussed as well as the weighing of the various propeller parameters against the design objectives. The noise generated by the propeller can be characterized as thrust noise due to the inhomogeneous...... wake field of the submarine, trailing-edge noise and noise caused by turbulence in the inflow. The items discussed are demonstrated in a case study where a propeller of the Kappel type was developed. Three stages of the development are presented, including a design of an 8-bladed propeller where...

  17. Russia's Submarine Force: Determinants and Prospects

    National Research Council Canada - National Science Library

    Tully, John

    2001-01-01

    ... the determinants of these events, The Russian Federation inherited a huge submarine fleet from the Soviet Union, Due to the changing conditions in the world and in Russia, its future status is in doubt...

  18. Low Noise Research Fan Stage Design

    Science.gov (United States)

    Hobbs, David E.; Neubert, Robert J.; Malmborg, Eric W.; Philbrick, Daniel H.; Spear, David A.

    1995-01-01

    This report describes the design of a Low Noise ADP Research Fan stage. The fan is a variable pitch design which is designed at the cruise pitch condition. Relative to the cruise setting, the blade is closed at takeoff and opened for reverse thrust operation. The fan stage is a split flow design with fan exit guide vanes and core stators. This fan stage design was combined with a nacelle and engine core duct to form a powered fan/nacelle, subscale model. This model is intended for use in aerodynamic performance, acoustic and structural testing in a wind tunnel. The model has a 22-inch outer fan diameter and a hub-to-top ratio of 0.426 which permits the use of existing NASA fan and cowl force balance designs and rig drive system. The design parameters were selected to permit valid acoustic and aerodynamic comparisons with the PW 17-inch rig previously tested under NASA contract. The fan stage design is described in detail. The results of the design axisymmetric analysis at aerodynamic design condition are included. The structural analysis of the fan rotor and attachment is described including the material selections and stress analysis. The blade and attachment are predicted to have adequate low cycle fatigue life, and an acceptable operating range without resonant stress or flutter. The stage was acoustically designed with airfoil counts in the fan exit guide vane and core stator to minimize noise. A fan-FEGV tone analysis developed separately under NASA contract was used to determine these airfoil counts. The fan stage design was matched to a nacelle design to form a fan/nacelle model for wind tunnel testing. The nacelle design was developed under a separate NASA contract. The nacelle was designed with an axisymmetric inlet, cowl and nozzle for convenience in testing and fabrication. Aerodynamic analysis of the nacelle confirmed the required performance at various aircraft operating conditions.

  19. SSN 774 Virginia Class Submarine (SSN 774)

    Science.gov (United States)

    2015-12-01

    Report: The VIRGINIA Class Submarine Program continues to deliver submarines within cost, ahead of schedule , with improved quality and with...baseline schedule threshold set ten years earlier, in 1994. June 20, 2006: USS TEXAS, which was essentially the second lead ship of the class , is the first...factored for the VIRGINIA Class based on weight. Public and private shipyard data was used, as well as the maintenance schedule provided in the CARD, Rev E

  20. WHO ARE FANS OF FACEBOOK FAN PAGES? AN ELECTRONIC WORD-OF-MOUTH COMMUNICATION PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Xiao Hu

    2014-12-01

    Full Text Available Given its great business value and popularity, Facebook fan pages have attracted more and more attention in both industry and academia. Fans of Facebook fan pages play an important role in electronic word-of-mouth (eWOM communication. This study focused on the population of fans on Facebook fan pages and examined the differences between fans and non-fans in terms of demographics, social network sites (SNS use, Internet use, and online shopping behaviors. The results indicated that fans used SNS more frequently than non-fans. Additionally, from the eWOM perspective, the researchers moderated product types in the model of people’s word-of-mouth (WOM preferences and found that people had different preferences for eWOM and traditional WOM for different products. Traditional WOM is still the most important source of information for people when shopping online.

  1. Characterisation of the surface morphology of an alpine alluvial fan using airborne LiDAR

    Directory of Open Access Journals (Sweden)

    M. Cavalli

    2008-04-01

    Full Text Available Alluvial fans of alpine torrents are both natural deposition areas for sediment discharged by floods and debris flows, and preferred sites for agriculture and settlements. Hazard assessment on alluvial fans depends on proper identification of flow processes and their potential intensity. This study used LiDAR data to examine the morphology of the alluvial fan of a small alpine stream (Moscardo Torrent, Eastern Italian Alps. A high-resolution DTM from LiDAR data was used to calculate a shaded relief map, plan curvature and an index of topographic roughness based on the standard deviation of elevation within a moving window. The surface complexity of the alluvial fan, also influenced by human activities, clearly arose from the analysis. The surface roughness, defined here as the local topography variability, is compared with a previous classification of the fan surface based on field surveys. The results demonstrate that topographic analysis of ground based LiDAR DTM can be a useful tool to objectively investigate fan morphology and hence alluvial fan hazard assessment.

  2. Football – Feminisation – Fans

    DEFF Research Database (Denmark)

    Mintert, Svenja-Maria

    Football has long time been considered as a genuine masculine domain. However, in the current football culture, the dualism of masculinity and femaleness is in progress. More and more women consume football which is in many countries considered the most popular sport, not only in Scandinavia where...... the number of female fans in football has grown over the past years. A national sense of community, emotion and passion for the game is in particular reached during the international tournaments at live football spectacles and many female fans cheer and sing for ‘their’ team with the utmost conviction. Yet......, the combination ‘women and football’ is still adhered to certain scepticism. Objective The overall objective of this Ph.D. thesis is to contribute to the body of knowledge associated with the distinct aspects of women’s football, female fandom and gender identities in European football drawing upon various...

  3. Blues fans and suicide acceptability.

    Science.gov (United States)

    Stack, S

    2000-01-01

    Research has neglected the possible impact of the blues music subculture on suicide acceptability (SA). The sad themes in the blues may attract suicidal persons and reinforce their suicidal moods and attitudes. The present study performs the first test of the thesis that associates SA with being a blues fan. It uses data on a national sample of 961 adults drawn from the General Social Survey of 1993. The results of a multivariate logistic regression analysis found that blues fans were no more accepting of suicide than nonfans. However, blues fanship was found to have substantial indirect effects on SA through its influence on such factors as lowered religiosity levels, the most important predictor of SA. Race-specific analyses found more support for the model for whites than for African Americans.

  4. Sub-decadal turbidite frequency during the early Holocene: Eel Fan, offshore northern California

    Science.gov (United States)

    Paull, Charles K.; McGann, Mary L.; Sumner, Esther J; Barnes, Philip M; Lundsten, Eve M.; Anderson, Krystle; Gwiazda, Roberto; Edwards, Brian D.; Caress, David W

    2014-01-01

    Remotely operated and autonomous underwater vehicle technologies were used to image and sample exceptional deep sea outcrops where an ∼100-m-thick section of turbidite beds is exposed on the headwalls of two giant submarine scours on Eel submarine fan, offshore northern California (USA). These outcrops provide a rare opportunity to connect young deep-sea turbidites with their feeder system. 14C measurements reveal that from 12.8 ka to 7.9 ka, one turbidite was being emplaced on average every 7 yr. This emplacement rate is two to three orders of magnitude higher than observed for turbidites elsewhere along the Pacific margin of North America. The turbidites contain abundant wood and shallow-dwelling foraminifera, demonstrating an efficient connection between the Eel River source and the Eel Fan sink. Turbidite recurrence intervals diminish fivefold to ∼36 yr from 7.9 ka onward, reflecting sea-level rise and re-routing of Eel River sediments.

  5. Field investigations of the interaction between debris flows and forest vegetation in two Alpine fans

    Science.gov (United States)

    Michelini, Tamara; Bettella, Francesco; D'Agostino, Vincenzo

    2017-02-01

    A key objective in debris-flow hazard mitigation is the reduction of the potential depositional area in the fan. From this point of view, forested areas are able to provide a protective function hindering the flow motion and promoting the surge deposition. Despite extensive research on Alpine forests and their protective functions, relatively few studies in the literature have quantitatively focused on the relationship between debris-flow depositional features and vegetation. In light of the above, our research investigates how vegetation characteristics in the fan area interact with debris-flow deposition. Field investigations were carried out in two Alpine fans where debris-flow events occurred in the summer of 2012. By recording the characteristics of 1567 involved trees and the associated deposit thicknesses, this paper provides a data set that contributes to the improvement of the knowledge of these interaction processes. The integration of literature findings and the analysis of the collected dataset adds insights into the relationships between tree characteristics and the dynamics of debris flow during the runout path. The main results prove the capacity of the forest of uniformly promoting flow-energy dissipation, presence of high species diversity in debris-flow deposits when comparing disturbed and undisturbed forest stands, tree mortality largely affecting small diameters management of protection forests in alluvial fans are suggested.

  6. Acoustic Power Transmission Through a Ducted Fan

    Science.gov (United States)

    Envia, Ed

    2016-01-01

    For high-speed ducted fans, when the rotor flowfield is shock-free, the main contribution to the inlet radiated acoustic power comes from the portion of the rotor stator interaction sound field that is transmitted upstream through the rotor. As such, inclusion of the acoustic transmission is an essential ingredient in the prediction of the fan inlet noise when the fan tip relative speed is subsonic. This paper describes a linearized Euler based approach to computing the acoustic transmission of fan tones through the rotor. The approach is embodied in a code called LINFLUX was applied to a candidate subsonic fan called the Advanced Ducted Propulsor (ADP). The results from this study suggest that it is possible to make such prediction with sufficient fidelity to provide an indication of the acoustic transmission trends with the fan tip speed.

  7. Geomorphology and sediment processes on the continental shelf and the submarine Akhziv canyon offshore north Galilee, eastern Mediterranean.

    Science.gov (United States)

    Ashqar, Lana; Bookman, Revital; Almogi-Labin, Ahuva; Ben-Avraham, Zvi

    2013-04-01

    The northern continental shelf of Israel is relatively steep and incised by submarine canyons. The Akhziv canyon is the largest and most developed and the southernmost in a series of canyons that formed off-shore Lebanon up to Beirut. The canyon is incised into the continental shelf 3 km from the northwestern Galilee coast to a depth of 1200 m. This study aims to understand processes responsible for the canyon morphology and the nature of sediment transport and accumulation mechanisms in the continental shelf and down the canyon to the deep sea. Moreover, the geological section in which the canyon is incised to, and the connection to the western Galilee fault system that transverse the continental shelf is explored for the regional perspective. Akhziv canyon consists of two main channels incised in cross-section V-shape at the upper part of the canyon that connect at 700m depth to produce a U-shaped main channel. The canyon's channels orientation implies a possible connection with the region's fault system. The high-resolution bathymetric map (the National Bathymetry Project) was used for the geomorphologic and morphometric analysis to define the connection between the canyon and the north- western Galilee streams that flow in a main east-west direction, parallel to the terrestrial fault system. Gaps in the submarine aeolian calcarenite ridge on the shallow shelf represent the continuation of terrestrial streams westward during low glacial sea level. Alluvial fans, mapped at 40m water depth, testify for sediment transport from land to the continental shelf toward the canyon head. Shallow high-resolution seismic lines (Sparker) were carried out along the continental shelf and canyon head to reveal the sub-surface structure. The seismic interpretation indicates the presence of channel incisions at depths of 10-15 m under the seafloor, with infill of young sediments which represents phases of deposition and erosion along the continental shelf. In addition, Piston

  8. The timing of sediment transport down Monterey Submarine Canyon, offshore California

    DEFF Research Database (Denmark)

    Stevens, Thomas; Paull, C.K.; Ussler, W., III

    2014-01-01

    to demonstrate relatively rapid, decadal-scale sand transport to at least 1.1 km depth and more variable decadal- to millennial-scale transport to a least 3.5 km depth on the fan. Significant differences between the time sand was last exposed at the canyon head (OSL age) and the timing of deposition of the sand...

  9. The Challenges of Teaching Fan Studies

    DEFF Research Database (Denmark)

    Stephan, Matthias

    , has only gained in popularity. Yet, the nature of the course in question, an interdisciplinary open elective, has meant a class with a variety of backgrounds, preparation, and expectations from fan studies and its critical apparatus. In addition, due to the course being taught in English, it attracts...... a conversation about the best methods for teaching fan studies, and help to open up fan studies to be integrated into other courses and programs....

  10. Newly recognized submarine slide complexes in the southern California Bight

    Science.gov (United States)

    Conrad, J. E.; Lee, H. J.; Edwards, B. D.; McGann, M.; Sliter, R. W.

    2012-12-01

    New high-resolution bathymetric and seismic-reflection surveys have imaged large (7) individual overlapping slides along the western margin of Santa Cruz Basin (SCB slide); 2) a series of slumps and slide scars on the slope south of San Pedro shelf (SPS slide); and 3) a slope failure along the shelf edge in northern San Diego County, termed the Del Mar slide. The SCB slide complex extends for 30 km along the western slope of Santa Cruz Basin, with debris lobes extending 5-8 km into the basin. Head scarps of some of these slides are 50-75 m high. The SPS slide complex also appears to consist of multiple slides, which roughly parallel the Palos Verdes Fault and the San Gabriel Canyon submarine channel on the shelf edge and slope south of San Pedro shelf. Slide deposits associated with this complex are only partially mapped due to limited high-resolution bathymetric coverage, but extend to the south in the area SW of Lasuen Knoll. Seismic-reflection profiles show that some of these deposits are up to 20 m thick. The Del Mar slide is located about 10 km north of La Jolla Canyon and extends about 6 km along the shelf edge. The head scarp lies along the trend of a branch of the Rose Canyon Fault Zone. Radiocarbon ages of sediment overlying this slide indicate the Del Mar slide is approximately 12-16 ka. These large slide complexes have several characteristics in common. Nearly all occur in areas of tectonic uplift. All of the complexes show evidence of recurrent slide activity, exhibiting multiple headwall scarps and debris lobes, and where available, high-resolution seismic-reflection profiles of these slide areas provide evidence of older, buried mass transport deposits. Assuming typical sedimentation rates, the recurrence interval of major slide events appears to be on the order of tens of thousands of years. Most of the slide complexes do not appear to be located in areas of high sediment input. The SCB and Del Mar slides are in areas receiving relatively small

  11. The creation of football slash fan fiction

    OpenAIRE

    Abby Waysdorf

    2015-01-01

    Although sports fandom and fan fiction are often thought of as different worlds, in the contemporary media environment, this is not the case. Sport is a popular source text for fan fiction, and high-level European football, one of the world's most watched sports, has long had an online fan fiction presence. In a study of the LiveJournal community Footballslash over the 2011–12 European football season, I investigate what makes football a suitable source text for fan fiction, especially slash ...

  12. 75 FR 43878 - Airworthiness Directives; DASSAULT AVIATION Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN...

    Science.gov (United States)

    2010-07-27

    ... Model Falcon 10 Airplanes; Model FAN JET FALCON, FAN JET FALCON SERIES C, D, E, F, and G Airplanes.... Since that NPRM was issued, we have determined that Model FAN JET FALCON SERIES C, D, E, F, and G... FALCON, FAN JET FALCON SERIES C, D, E, F, and G airplanes, and Model MYSTERE-FALCON 20-C5, 20-D5, 20-E5...

  13. Fan Fuel Casting Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Imhoff, Seth D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-28

    LANL was approached to provide material and design guidance for a fan-shaped fuel element. A total of at least three castings were planned. The first casting is a simple billet mold to be made from high carbon DU-10Mo charge material. The second and third castings are for optimization of the actual fuel plate mold. The experimental scope for optimization is only broad enough for a second iteration of the mold design. It is important to note that partway through FY17, this project was cancelled by the sponsor. This report is being written in order to capture the knowledge gained should this project resume at a later date.

  14. Sediment community responses to marine vs. terrigenous organic matter in a submarine canyon

    OpenAIRE

    Hunter, W. R.; Jamieson, A; Huvenne, V. A. I.; Witte, U

    2013-01-01

    The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM) transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days) responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii) and ni...

  15. Deformation microstructures and timing of a large submarine landslide drilled offshore Martinique (IODP Exp. 340)

    Science.gov (United States)

    Guyard, H.; Le Friant, A.; Brunet, M.; Boudon, G.; Emmanuel, L.; Caron, B.; Villemant, B.; Feuillet, N.

    2015-12-01

    Flank-instabilities constitute a recurrent process in the long-term evolution of many volcanoes. A very large submarine landslide deposit (~2100 km2, ~300 km3) drilled southwest Martinique island during the IODP Exp. 340 in 2012 is likely associated with one (or more) major volcanic flank collapse of Mount Pelée during the Late Pleistocene. A recent study revealed that this D1/D2 deposit is emergent in its central part, frontally confined, and mainly comprises remobilized seafloor sediments rather than debris avalanche material from the volcanic edifice (Brunet et al., subm). Here, we investigate the sedimentary microstructures and timing of deformation from the central (Hole 1400B, ~37 km from the coastline) and distal (Hole 1399A, ~70 km from the coastline) units of the D1/D2 deposit, in order to better understand the emplacement dynamics of such potentially tsunamigenic submarine landslides. High resolution CT-Scan analyses were continuously performed on more than 300 m of sediment cores, in order to characterize and distinguish the internal architecture and the complex deformation features of the sediments at each drilling site. The establishment of the stratigraphy, based on δ18O measurements and AMS 14C dating, is still in progress and may confirm the possible link between the submarine landslide deposits and the flank collapse scars observed on the subaerial part of Martinique. These new insights into the timing and emplacement processes of this large submarine landslide will have important implications for tsunami hazards. ReferenceBrunet, M., Le Friant, A., Boudon, G., Lafuerza, S., Talling, P., Hornbach, M., Lebas, E., Guyard, H., and IODP Expedition 340 science party, submitted. Composition, geometry and emplacement dynamics of a large volcanic island landslide offshore Martinique: from volcano flank-collapse to seafloor sediment failure? Geochemistry, Geophysics, Geosystems.

  16. Impact of Submarine Geohazards on Organic Carbon Burial Offshore Southwestern Taiwan

    Science.gov (United States)

    Su, C. C.; Tsai, P. H.; Liu, J. T.; Hsu, S. K.; Chiu, S. D.

    2015-12-01

    The tectonically active setting and climatic conditions give Taiwan a high exposure to severe natural hazards. After the Pingtung Earthquake and Morakot Typhoon which occurred in 2006 and 2009, the turbidity currents caused a series of submarine cable breaks along the Gaoping and Fangliao Submarine Canyons off SW Taiwan. Large amounts of terrestrial sediments were fast transported bypass the narrow continental shelf and rapidly moved southward through submarine canyons to the deep sea. Two piston cores which were taken from the Tsangyao Ridge and its adjacent area (OR5-1302-2-MT7 and MT6) might shed light on understanding the export of terrestrial organic carbon to the abyss by submarine geo-hazards. The 210Pb profile of MT7 in conjunction with the grain size data indicates the existence of the Pingtung Earthquake and Morakot Typhoon related deposits. The sedimentation rate of these two cores which derived from 210Pb is approximately 0.05 cm/yr. The cores collected from the Gaoping Submarine Canyon, Gaoping Slope and Fangliao Submarine Canyon are used for analyzing TOC, organic C/N and δ13C ratios. The concentrations of total organic carbon are ~0.5%, and C/N rations almost remain between 4 and 8. The high TOC (~1%) and C/N ratio (>10) are observed in the samples with plant debris. The fluctuation of TOC and C/N ratios in near-shore samples is higher than deep sea. In terms of δ13C-values, it progressively decreases with distances from coastal zone to the deep sea. Due to the larger proportions of land-derived organic carbon, the δ13C-values in the surface sediment of upper Gaoping Submarine Canyon, Gaoping Slope, and the turbidite layers at the head of Fangliao Submarine Canyon are lighter. Furthermore, we use the TOC concentrations and δ13C-values to estimate the fractional contributions of terrestrial organic carbon by a simple two component mixing model, and integrate with the 210Pb-derived sediment accumulation rates to evaluate the organic carbon burial

  17. Erosion dynamics in a coupled catchment- fan system under constant external forcing

    Science.gov (United States)

    Pepin, E.; Carretier, S.; Herail, G.

    2009-04-01

    Changes in external forcing like climate or tectonic uplift are known to control the geomorphological evolution of mountain catchments and associated alluvial fans. For this reason, geomorphologic studies often use landscape morphologies like entrenchment as a marker of past climate or tectonic changes. However, recent studies have shown that the evolution of a catchment-fan system could also depend strongly on autogenic mechanisms and feedbacks between mountains and fans. These feedbacks can be strong because on one hand, the elevation of alluvial fans determines the base level of mountain catchments, and on the other hand, fluxes exiting on mountain catchments feed the piedmont fans. Thus, any change in one of the sub-system affects the other one. Recent theoretical studies showed that deep fan entrenchment could occur without any changes of influxes. We evaluate the conditions for such a behavior in a coupled catchment-fan system using a landscape evolution model (CIDRE). The mountain corresponds to an uplifting block and fans form over an initial horizontal surface. We confirm that deep entrenchment at fan apex can occur, pending to two necessary conditions: 1- transport threshold (critical shear stress) is significant and 2- the downstream boundary condition corresponds to a transversal river able to carry all incoming sediments. The entrenchment occurs always when sediments reach this boundary condition and then, it remains stable. It occurs whatever the evolution state of the mountain (transient or equilibrium). This could be explained by a depositional slope close to the critical transport slope during fan progradation, and then by a fan slope increase which allows the transport threshold to be overpassed. Fan entrenchment drives a strong erosion in the mountain, with an intensity and a response time similar to those observed for the initial mountain uplift. These results indicate that determining the part of natural erosion by autogenic mechanisms is

  18. Autogenic dynamics of debris-flow fans

    Science.gov (United States)

    van den Berg, Wilco; de Haas, Tjalling; Braat, Lisanne; Kleinhans, Maarten

    2015-04-01

    Alluvial fans develop their semi-conical shape by cyclic avulsion of their geomorphologically active sector from a fixed fan apex. These cyclic avulsions have been attributed to both allogenic and autogenic forcings and processes. Autogenic dynamics have been extensively studied on fluvial fans through physical scale experiments, and are governed by cyclic alternations of aggradation by unconfined sheet flow, fanhead incision leading to channelized flow, channel backfilling and avulsion. On debris-flow fans, however, autogenic dynamics have not yet been directly observed. We experimentally created debris-flow fans under constant extrinsic forcings, and show that autogenic dynamics are a fundamental intrinsic process on debris-flow fans. We found that autogenic cycles on debris-flow fans are driven by sequences of backfilling, avulsion and channelization, similar to the cycles on fluvial fans. However, the processes that govern these sequences are unique for debris-flow fans, and differ fundamentally from the processes that govern autogenic dynamics on fluvial fans. We experimentally observed that backfilling commenced after the debris flows reached their maximum possible extent. The next debris flows then progressively became shorter, driven by feedbacks on fan morphology and flow-dynamics. The progressively decreasing debris-flow length caused in-channel sedimentation, which led to increasing channel overflow and wider debris flows. This reduced the impulse of the liquefied flow body to the flow front, which then further reduced flow velocity and runout length, and induced further in-channel sedimentation. This commenced a positive feedback wherein debris flows became increasingly short and wide, until the channel was completely filled and the apex cross-profile was plano-convex. At this point, there was no preferential transport direction by channelization, and the debris flows progressively avulsed towards the steepest, preferential, flow path. Simultaneously

  19. Possible climate preconditioning on submarine landslides along a convergent margin, Nankai Trough (NE Pacific)

    Science.gov (United States)

    Kremer, Katrina; Usman, Muhammed O.; Satoguchi, Yasufumi; Nagahashi, Yoshitaka; Vadakkepuliyambatta, Sunil; Panieri, Giuliana; Strasser, Michael

    2017-12-01

    Submarine landslides are major agents of sediment mass transfer from the shallow to deep sea. Due to their rapid emplacement and tsunamigenic potential, such landslides are significant geohazards for society and off- and on-shore infrastructure. The relationship between climate change and the occurrence of submarine landslides is widely debated. However, there is a lack of continuous long-term submarine landslide records with which to comprehensively understand the relationship between climate-driven forces and submarine landslide occurrence. Here, using oxygen isotope stratigraphy in combination with tephrochronology, we date a 1 Myr continuous record of six landslide deposits (at 13.0-14.2, 323-339, 372-384, 394-413, 508-521, and 857-867 ka) recorded in a slope basin of the Nankai Trough subduction zone, off-shore Japan, which represents the major outcome of this study. The ages of the six landslides coincide mostly with interglacial periods. Thus, we propose that climate forcing might act as a preconditioning factor for slope instability in this active tectonic region.[Figure not available: see fulltext.

  20. Geomorphic process fingerprints in submarine canyons

    Science.gov (United States)

    Brothers, Daniel S.; ten Brink, Uri S.; Andrews, Brian D.; Chaytor, Jason D.; Twichell, David C.

    2013-01-01

    Submarine canyons are common features of continental margins worldwide. They are conduits that funnel vast quantities of sediment from the continents to the deep sea. Though it is known that submarine canyons form primarily from erosion induced by submarine sediment flows, we currently lack quantitative, empirically based expressions that describe the morphology of submarine canyon networks. Multibeam bathymetry data along the entire passive US Atlantic margin (USAM) and along the active central California margin near Monterey Bay provide an opportunity to examine the fine-scale morphology of 171 slope-sourced canyons. Log–log regression analyses of canyon thalweg gradient (S) versus up-canyon catchment area (A) are used to examine linkages between morphological domains and the generation and evolution of submarine sediment flows. For example, canyon reaches of the upper continental slope are characterized by steep, linear and/or convex longitudinal profiles, whereas reaches farther down canyon have distinctly concave longitudinal profiles. The transition between these geomorphic domains is inferred to represent the downslope transformation of debris flows into erosive, canyon-flushing turbidity flows. Over geologic timescales this process appears to leave behind a predictable geomorphic fingerprint that is dependent on the catchment area of the canyon head. Catchment area, in turn, may be a proxy for the volume of sediment released during geomorphically significant failures along the upper continental slope. Focused studies of slope-sourced submarine canyons may provide new insights into the relationships between fine-scale canyon morphology and down-canyon changes in sediment flow dynamics.

  1. Supercritical flows and their control on the architecture and facies of small-radius sand-rich fan lobes

    Science.gov (United States)

    Postma, George; Kleverlaan, Kick

    2018-02-01

    New insights into flow characteristics of supercritical, high-density turbidity currents initiated renewed interest in a sand-rich lobe complex near the hamlet of Mizala in the Sorbas Basin (Tortonian, SE Spain). The field study was done using drone-made images taken along bed strike in combination with physical tracing of bounding surfaces and section logging. The studied lobe systems show a consistent built-up of lobe elements of 1.5-2.0 m thick, which form the building 'blocks' of the lobe system. The stacking of lobe elements shows lateral shift and compensational relief infill. The new model outlined in this paper highlights three stages of fan lobe development: I. an early aggradational stage with lobe elements characterized by antidune and traction-carpet bedforms and burrowed mud intervals (here called 'distal fan' deposits); II. a progradational stage, where the distal fan deposits are truncated by lobe elements of amalgamated sandy to gravelly units characterized by cyclic step bedform facies (designated as 'supra fan' deposits). The supra fan is much more channelized and scoured and of higher flow energy than the distal-fan. Aggradation of the supra-fan is terminated by a 'pappy' pebbly sandstone and by substrate liquefaction, 'pappy' referring to a typical, porridge-like texture indicating rapid deposition under conditions of little-to-no shear. The facies-bounded termination of the supra-fan is here related to its maximum elevation, causing the lobe-feeding supercritical flow to choke and to expand upwards by a strong hydraulic jump at the channel outlet; III. a backfilling stage, characterized by backfilling of the remaining relief with progressively thinning and fining of turbidite beds and eventually with mud. The three-stage development for fan-lobe building is deducted from reoccurring architectural and facies characteristics in three successive fan-lobes. The validity of using experimental, supercritical-flow fan studies for understanding the

  2. Controls of the water and sediment fluxes on alluvial fans morphology: theory and experiments

    Science.gov (United States)

    Guerit, Laure; Delorme, Pauline; Métivier, François; Lajeunesse, Eric; Devauchelle, Olivier; Barrier, Laurie

    2015-04-01

    Alluvial fans are major sedimentary bodies that make the transition between the reliefs in erosion and the sedimentary basins, where deposition occurs. Understanding their dynamics of formation and evolution is a great problem of sediment transport, which leads to a better understanding of the control exerted by the water and sediment fluxes on the fan morphology. At the cost of several simplifications, we propose a totally predictive model for one-dimensional fans composed by one grain size and built under laminar flow. In this simplified context, it is possible to propose a unique relationship between the water flux, the sediment flux, the grain size and the slope of the fan. The theory is validated by one-dimension experiments, performed with glass beads and glycerine: the fan grows quasi-statically and maintains its slope just above the threshold for sediment transport. In addition, at leading order, the sediment discharge only controls the velocity at which the fan grows. These main predictions are then successfully tested in two-dimensional experiments.

  3. The Right to Be a Fan

    Science.gov (United States)

    Gutierrez, Peter

    2011-01-01

    Reading experts have consistently cited the importance of independent reading, reading for pleasure, and fostering "a love of reading." Unfortunately, fanning the fire of fan readership is not so easy in the service of our clear-cut and standards-aligned curricula, except perhaps in small, carefully channeled doses. Moreover, the impetus for such…

  4. The creation of football slash fan fiction

    Directory of Open Access Journals (Sweden)

    Abby Waysdorf

    2015-06-01

    Full Text Available Although sports fandom and fan fiction are often thought of as different worlds, in the contemporary media environment, this is not the case. Sport is a popular source text for fan fiction, and high-level European football, one of the world's most watched sports, has long had an online fan fiction presence. In a study of the LiveJournal community Footballslash over the 2011–12 European football season, I investigate what makes football a suitable source text for fan fiction, especially slash fan fiction; what fan fiction authors are doing with football; and what this suggests about how football and fan fiction are used in the present day. I present a new understanding of football as a media text to be transformed as well as provide an in-depth look into how this type of real person slash is developed and thought of by its practitioners. In doing so, I show what happens when fandoms and fan practices converge in the 21st century.

  5. Quantifying Channelized Submarine Depositional Systems From Bed to Basin Scale

    Science.gov (United States)

    2004-09-01

    topography. Sample locations are indicated by circles and labeled with alpha- numeric identifiers. See Table 5.1 for sample characteristics...e.g. Dietrich et al. (2003)). Steady state or equilibrium topography therefore requires a regenerative source/sink term in the form of rock uplift or...been dated directly using recovered assemblages of mi- crofossils from multiple wellbores in the basin. The basin-wide mapping of regional surfaces

  6. Hawaiian submarine manganese-iron oxide crusts - A dating tool?

    Science.gov (United States)

    Moore, J.G.; Clague, D.A.

    2004-01-01

    Black manganese-iron oxide crusts form on most exposed rock on the ocean floor. Such crusts are well developed on the steep lava slopes of the Hawaiian Ridge and have been sampled during dredging and submersible dives. The crusts also occur on fragments detached from bedrock by mass wasting, on submerged coral reefs, and on poorly lithified sedimentary rocks. The thickness of the crusts was measured on samples collected since 1965 on the Hawaiian Ridge from 140 dive or dredge localities. Fifty-nine (42%) of the sites were collected in 2001 by remotely operated vehicles (ROVs). The thinner crusts on many samples apparently result from post-depositional breakage, landsliding, and intermittent burial of outcrops by sediment. The maximum crust thickness was selected from each dredge or dive site to best represent crusts on the original rock surface at that site. The measurements show an irregular progressive thickening of the crusts toward the northwest-i.e., progressive thickening toward the older volcanic features with increasing distance from the Hawaiian hotspot. Comparison of the maximum crust thickness with radiometric ages of related subaerial features supports previous studies that indicate a crust-growth rate of about 2.5 mm/m.y. The thickness information not only allows a comparison of the relative exposure ages of two or more features offshore from different volcanoes, but also provides specific age estimates of volcanic and landslide deposits. The data indicate that some of the landslide blocks within the south Kona landslide are the oldest exposed rock on Mauna Loa, Kilauea, or Loihi volcanoes. Crusts on the floors of submarine canyons off Kohala and East Molokai volcanoes indicate that these canyons are no longer serving as channelways for downslope, sediment-laden currents. Mahukona volcano was approximately synchronous with Hilo Ridge, both being younger than Hana Ridge. The Nuuanu landslide is considerably older than the Wailau landslide. The Waianae

  7. Blade Vibration Measurement System for Unducted Fans

    Science.gov (United States)

    Marscher, William

    2014-01-01

    With propulsion research programs focused on new levels of efficiency and noise reduction, two avenues for advanced gas turbine technology are emerging: the geared turbofan and ultrahigh bypass ratio fan engines. Both of these candidates are being pursued as collaborative research projects between NASA and the engine manufacturers. The high bypass concept from GE Aviation is an unducted fan that features a bypass ratio of over 30 along with the accompanying benefits in fuel efficiency. This project improved the test and measurement capabilities of the unducted fan blade dynamic response. In the course of this project, Mechanical Solutions, Inc. (MSI) collaborated with GE Aviation to (1) define the requirements for fan blade measurements; (2) leverage MSI's radar-based system for compressor and turbine blade monitoring; and (3) develop, validate, and deliver a noncontacting blade vibration measurement system for unducted fans.

  8. Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps

    Science.gov (United States)

    Marchi, L.; Cavalli, M.; D'Agostino, V.

    2010-03-01

    Alluvial fans are often present at the outlet of small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and debris flows. Alluvial fans are preferred sites for human settlements and are frequently crossed by transport routes. In order to reduce the risk for economic activities located on or near the fan and prevent loss of lives due to floods and debris flows, torrent control works have been extensively carried out on many alpine alluvial fans. Hazard management on alluvial fans in alpine regions is dependent upon reliable procedures to evaluate variations in the frequency and severity of hydrogeomorphic processes and the long-term performance of the torrent training works. An integrated approach to the analysis of hydrogeomorphic processes and their interactions with torrent control works has been applied to a large alluvial fan in the southern Carnic Alps (northeastern Italy). Study methods encompass field observations, interpretation of aerial photographs, analysis of historical documents, and numerical modelling of debris flows. The overall performance of control works implemented in the early decades of 20th century was satisfactory, and a reduction of hazardous events was recognised from features observed in the field and in aerial photographs, as well as from the analysis of historical records. The 2-D simulation of debris flows confirms these findings, indicating that debris flow deposition would not affect urban areas or main roads, even in the case of a high-magnitude event. Present issues in the management of the studied alluvial fan are representative of situations frequently found in the European Alps and deal with the need for maintenance of the control structures and the pressures for land use changes aimed at the economic exploitation of the fan surface.

  9. Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps

    Directory of Open Access Journals (Sweden)

    L. Marchi

    2010-03-01

    Full Text Available Alluvial fans are often present at the outlet of small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and debris flows. Alluvial fans are preferred sites for human settlements and are frequently crossed by transport routes. In order to reduce the risk for economic activities located on or near the fan and prevent loss of lives due to floods and debris flows, torrent control works have been extensively carried out on many alpine alluvial fans. Hazard management on alluvial fans in alpine regions is dependent upon reliable procedures to evaluate variations in the frequency and severity of hydrogeomorphic processes and the long-term performance of the torrent training works. An integrated approach to the analysis of hydrogeomorphic processes and their interactions with torrent control works has been applied to a large alluvial fan in the southern Carnic Alps (northeastern Italy. Study methods encompass field observations, interpretation of aerial photographs, analysis of historical documents, and numerical modelling of debris flows. The overall performance of control works implemented in the early decades of 20th century was satisfactory, and a reduction of hazardous events was recognised from features observed in the field and in aerial photographs, as well as from the analysis of historical records. The 2-D simulation of debris flows confirms these findings, indicating that debris flow deposition would not affect urban areas or main roads, even in the case of a high-magnitude event. Present issues in the management of the studied alluvial fan are representative of situations frequently found in the European Alps and deal with the need for maintenance of the control structures and the pressures for land use changes aimed at the economic exploitation of the fan surface.

  10. Quaternary alluvial fans of Ciudad Juárez, Chihuahua, northern México: OSL ages and implications for climatic history of the region

    Science.gov (United States)

    Zúñiga de León, David; Kershaw, Stephen; Mahan, Shannon

    2016-01-01

    Alluvial fans formed from sediments derived from erosion of the Juárez Mountains in northernmost México have a significant flood impact on the Ciudad Juárez, which is built on the fan system. The northern part of Ciudad Juárez is the most active; further south, older parts of the fan, upon which the rest of the city is built, were largely eroded by natural processes prior to human habitation and subsequently modified only recently by human construction. Three aeolian sand samples, collected from the uppermost (youngest) parts of the fan system in the city area, in places where human intervention has not disturbed the sediment, and constrain the latest dates of fan building. Depositional ages of the Quaternary alluvial fans were measured using Optically Stimulated Luminescence (OSL) on aeolian sands that have inter-fingered with alluvial fan material. These dates are: a) sample P1, 31 ka; b) sample P2, 41 ka; c) sample P3, 74 ka, between Oxygen Isotope Stages (OIS) 3 to 5. They demonstrate that fan development, in the area now occupied by the city, terminated in the Late Pleistocene, immediately after what we interpret to have been an extended period of erosion without further deposition, lasting from the Late Pleistocene to Holocene. The three dates broadly correspond to global glacial periods, implying that the cool, dry periods may reflect periods of aeolian transport in northern México in between phases that were wetter to form the alluvial fans. Alluvial fan margins inter-finger with fluvial terrace sediments derived from the Río Bravo, indicating an additional component of fan dissection by Río Bravo lateral erosion, presumed to be active during earlier times than our OSL ages, but these are not yet dated. Further dating is required to ascertain the controls on the fan and fluvial system.

  11. Football – Feminisation – Fans

    DEFF Research Database (Denmark)

    Mintert, Svenja-Maria

    The researcher reviewed relevant primary and secondary literature relating to women’s football, female football consumption and identity dynamics in a European perspective. Between March and August 2013, 31 semi-structured interviews with Danish women aged between 24 and 60 years were conducted following......Football has long time been considered as a genuine masculine domain. However, in the current football culture, the dualism of masculinity and femaleness is in progress. More and more women consume football which is in many countries considered the most popular sport, not only in Scandinavia where...... and interpretation of the sport. Research question The overarching research question centres upon how and to what extent the role of gender in football and fan cultures is manifested with a particular focus on gender-specific patterns of crosscultural communication and identification. Methods and Approach...

  12. Debris-flow dominance of alluvial fans masked by runoff reworking and weathering

    Science.gov (United States)

    de Haas, Tjalling; Ventra, Dario; Carbonneau, Patrice E.; Kleinhans, Maarten G.

    2014-07-01

    deposits and accumulate fine sediment in low-gradient distal channels, forming a well-developed drainage pattern that would suggest a runoff origin from aerial images. Nevertheless, reworking is very superficial and barely preserved in the stratigraphic record. This implies that fans on Earth and Mars that formed dominantly by sporadic mass flows may be masked by a surface morphology related to other processes.

  13. Addressing submarine geohazards through scientific drilling

    Science.gov (United States)

    Camerlenghi, A.

    2009-04-01

    Natural submarine geohazards (earthquakes, volcanic eruptions, landslides, volcanic island flank collapses) are geological phenomena originating at or below the seafloor leading to a situation of risk for off-shore and on-shore structures and the coastal population. Addressing submarine geohazards means understanding their spatial and temporal variability, the pre-conditioning factors, their triggers, and the physical processes that control their evolution. Such scientific endeavour is nowadays considered by a large sector of the international scientific community as an obligation in order to contribute to the mitigation of the potentially destructive societal effects of submarine geohazards. The study of submarine geohazards requires a multi-disciplinary scientific approach: geohazards must be studied through their geological record; active processes must be monitored; geohazard evolution must be modelled. Ultimately, the information must be used for the assessment of vulnerability, risk analysis, and development of mitigation strategies. In contrast with the terrestrial environment, the oceanic environment is rather hostile to widespread and fast application of high-resolution remote sensing techniques, accessibility for visual inspection, sampling and installation of monitoring stations. Scientific Drilling through the IODP (including the related pre site-survey investigations, sampling, logging and in situ measurements capability, and as a platform for deployment of long term observatories at the surface and down-hole) can be viewed as the centre of gravity of an international, coordinated, multi-disciplinary scientific approach to address submarine geohazards. The IODP Initial Science Plan expiring in 2013 does not address openly geohazards among the program scientific objectives. Hazards are referred to mainly in relation to earthquakes and initiatives towards the understanding of seismogenesis. Notably, the only drilling initiative presently under way is the

  14. MVAC Submarine cable, impedance measurements and analysis

    DEFF Research Database (Denmark)

    Arentsen, Martin Trolle; Pedersen, Morten Virklund; Expethit, Adrian

    2017-01-01

    Due to environmental concerns an increase in off-shore windfarms has been observed in recent years, leading to an increased demand for three-core-wire-armoured submarine cables. However, the IEC Standard 60287 used to calculate the ampacity of these cables is widely recognized as being not accurate...

  15. German Submarine Offensives and South African Countermeasures

    African Journals Online (AJOL)

    Evert

    'Good Hunting': German Submarine Offensives and South African. Countermeasures off the South African Coast during the Second World. War, 1942-1945. Evert Kleynhans. •. Abstract .... wolf packs south, Dönitz had hoped to cause a diversionary effect whereby the Allies would be forced to split their defensive forces ...

  16. Submarine Telecommunication Cables in Disputed Maritime Areas

    NARCIS (Netherlands)

    van Logchem, Youri

    2014-01-01

    There are a considerable number of maritime areas where no boundary exists, or where a boundary is delimited only in part. This article deals with the issue of submarine telecommunication cables, which are sometimes placed on the seabed or buried in the subsoil of areas that are claimed by multiple

  17. Monitoring of the nuclear submarine Komsomolets

    Energy Technology Data Exchange (ETDEWEB)

    Heldal, Hilde E.; Flo, Janita K.; Liebig, Penny L. [Institute of Marine Research, P. O. Box 1870 Nordnes, N-5817 Bergen (Norway); Gaefvert, Torbjoern; Rudjord, Anne Liv [Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Oesteraas (Norway); Gwynn, Justin P. [Norwegian Radiation Protection Authority, The Fram Centre, N-9296 Tromsoe (Norway)

    2014-07-01

    The Soviet nuclear submarine Komsomolets sank on the 7 April 1989, 180 km southwest of Bear Island in the Norwegian Sea to a depth of about 1655 m. The submarine contains one nuclear reactor containing long-lived radionuclides such as cesium-137 ({sup 137}Cs) along with other fission and activation products, in addition to 2 mixed uranium/plutonium nuclear warheads containing weapons grade plutonium. Although several model studies have shown that a radioactive leakage from Komsomolets will have insignificant impact on fish and other marine organisms, there are still public concerns about the condition of the submarine and the potential for radioactive leakage. In order to document the contamination levels and to meet public concerns, monitoring of radioactive contamination in the area adjacent to the submarine has been ongoing since 1993. Samples of bottom seawater and sediments have been collected annually by the Institute of Marine Research (IMR) and have been analysed for {sup 137}Cs and plutonium-239,240 ({sup 239,240}Pu). So far, activity concentrations in the samples have been comparable to levels found in other samples from the Norwegian and Barents Seas. During sampling from R/V 'G. O. Sars' in April 2013, an area of about 1 km{sup 2} of the seabed around Komsomolets was mapped to precisely locate the submarine using a Kongsberg EM302 multibeam echo sounder, a Simrad EK60 single beam echo sounder and an Olex 3D bottom-mapping system. For sediment sampling, a Simrad MST342 mini-transponder was attached to a Smoegen box corer to allow for precise positioning of the corer. With the aid of the Kongsberg HiPAP (High Precision Acoustic Positioning) system, 4 box cores were collected around the submarine at a distance of 10 to 20 m. In addition, one box core was collected from a reference station about 100 m upstream of the submarine. Surface sediments and sediment cores were collected from the box cores taken at each sampling location. Sediment cores

  18. Chemical environments of submarine hydrothermal systems

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine hydrothermal systems were involved in the origin of life has caused many investigators to focus on the eye-catching hydrothermal vents. In much the same way that tourists rush to watch the spectacular eruptions of Old Faithful geyser with little regard for the hydrology of the Yellowstone basin, attention is focused on the spectacular, high-temperature hydrothermal vents to the near exclusion of the enormous underlying hydrothermal systems. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine hydrothermal systems. However, in the submarine systems the scale can be considerably more vast. Like Old Faithful, submarine hydrothermal vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic systems operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of hydrothermal processes in the origin of life should include the full spectrum of probable environments. The goals of this chapter are to synthesize diverse information about the inorganic geochemistry of submarine hydrothermal systems, assemble a description of the fundamental physical and chemical attributes of these systems, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine hydrothermal systems comes from many directions. Measurements made directly on venting fluids provide useful, but remarkably limited, clues about processes operating at depth. The oceanic crust has been drilled to approximately 2.0 km depth providing many other pieces of information, but drilling technology has not allowed the bore holes and core samples to reach the maximum depths to which aqueous fluids circulate in oceanic crust. Such

  19. Phase 1 Final Report: Titan Submarine

    Science.gov (United States)

    Oleson, Steven R.; Lorenz, Ralph D.; Paul, Michael V.

    2015-01-01

    The conceptual design of a submarine for Saturn's moon Titan was a funded NASA Innovative Advanced Concepts (NIAC) Phase 1 for 2014. The proposal stated the desire to investigate what science a submarine for Titan's liquid hydrocarbon seas might accomplish and what that submarine might look like. Focusing on a flagship class science system (100 kg), it was found that a submersible platform can accomplish extensive science both above and below the surface of the Kraken Mare. Submerged science includes mapping using side-looking sonar, imaging and spectroscopy of the lake, as well as sampling of the lake's bottom and shallow shoreline. While surfaced, the submarine will not only sense weather conditions (including the interaction between the liquid and atmosphere) but also image the shoreline, as much as 2 km inland. This imaging requirement pushed the landing date to Titan's next summer period (2047) to allow for lighted conditions, as well as direct-to-Earth communication, avoiding the need for a separate relay orbiter spacecraft. Submerged and surfaced investigation are key to understanding both the hydrological cycle of Titan as well as gather hints to how life may have begun on Earth using liquid, sediment, and chemical interactions. An estimated 25 Mb of data per day would be generated by the various science packages. Most of the science packages (electronics at least) can be safely kept inside the submarine pressure vessel and warmed by the isotope power system.The baseline 90-day mission would be to sail submerged and surfaced around and through Kraken Mare investigating the shoreline and inlets to evaluate the sedimentary interaction both on the surface and then below. Depths of Kraken have yet to be sensed (Ligeia to the north is thought to be 200 m (656 ft) deep), but a maximum depth of 1,000 m (3,281 ft) for Kraken Mare was assumed for the design). The sub would spend 20 d at the interface between Kraken Mare and Ligeia Mare for clues to the drainage of

  20. Small fan-in is beautiful

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.; Makaruk, H.E.

    1997-09-01

    The starting points of this paper are two size-optimal solutions: (1) one for implementing arbitrary Boolean functions; and (2) another one for implementing certain subclasses of Boolean functions. Because VLSI implementations do not cope well with highly interconnected nets -- the area of a chip grows with the cube of the fan-in -- this paper will analyze the influence of limited fan-in on the size optimality for the two solutions mentioned. First, the authors will extend a result from Horne and Hush valid for fan-in {Delta} = 2 to arbitrary fan-in. Second, they will prove that size-optimal solutions are obtained for small constant fan-ins for both constructions, while relative minimum size solutions can be obtained for fan-ins strictly lower that linear. These results are in agreement with similar ones proving that for small constant fan-ins ({Delta} = 6...9) there exist VLSI-optimal (i.e., minimizing AT{sup 2}) solutions, while there are similar small constants relating to the capacity of processing information.

  1. Pliocene-Pleistocene climate change, sea level and uplift history recorded by the Horingbaai fan-delta, NW Namibia

    Science.gov (United States)

    Stollhofen, Harald; Stanistreet, Ian G.; von Hagke, Christoph; Nguno, Anna

    2014-07-01

    Its location on a tectonically relatively stable passive margin and its degree of interaction with the sea make the Horingbaai fan-delta, NW Namibia, an exceptional record of coastal activity, providing insights into the response of ephemeral fluvial systems to changes in climate, sea level and continent-scale uplift. The fan comprises upper, middle and lower segments. The upper fan and middle fan are dominated by a braided river system; only in the upper fan are fluvial sediments interleaved with hyperconcentrated flow deposits. Plio-Pleistocene sea level highstands have left marine terraces on the fan surface which enable correlation with the offshore marine record and provide timelines to constrain fan growth. The bulk of fan-delta progradation took place at ∼ 2.7-2.4 Ma, between the formation of a widespread erosional surface incising the middle Pliocene Karpfenkliff and Kamberg Formations, but prior to the emplacement of the warm-water fauna-bearing late Pliocene "Oyster Terrace" (∼ 2.4-2.2 Ma), an equivalent of the + 30 mP (marine terrace package) in coastal southwestern Africa. Major fan progradation is contemporaneous with widespread regional uplift (~ 12 ± 5 m/Ma) and climate change in southwestern Africa, the latter associated with intensification of northern hemisphere glaciations. Younger fan growth phases are weaker and constrained by < 10 m asl marine terrace bodies that yield mostly cold-water fauna, corresponding to the onset of strong glacial/interglacial climatic fluctuations superimposed on a general aridification trend and the introduction of colder sea-surface temperatures after 2.2 Ma.

  2. Sherlock (Holmes in Japanese (fan works [symposium

    Directory of Open Access Journals (Sweden)

    Lori Morimoto

    2017-03-01

    Full Text Available I explore the history of Japanese writing centered on Sherlock Holmes as a means of interrogating the 2014 BBC Sherlock pastiche John and Sherlock Casebook 1: Jon, zenchi renmei e iku (The stark naked league, written by Japanese Sherlockian Kitahara Naohiko for mainstream publication by the publishing house Hayakawa shobō. I argue that exploration of the Japanese (fan cultural contexts of Kitahara's book begins to reveal the limits of the Anglo-American-centered framework through which fan studies scholars explore fan/producer relationships.

  3. The practice of fans; Pratique des ventilateurs

    Energy Technology Data Exchange (ETDEWEB)

    Lexis, J.

    2001-07-01

    This book treats of fans and of their role in ventilation and air conditioning systems. All types of equipment are presented with their conditions of utilisation and installation. The book details also the techniques of tuning and regulation and proposes several practical examples of calculations: impact on the fan of modifications made on the air-conditioning network, in-series and in-parallel operation of several fans, duct fittings and pressure drops, acoustic treatment and anti-vibrational insulation, etc.. (J.S.)

  4. Attitudes of football fans in lower league

    OpenAIRE

    Černý, Miroslav

    2012-01-01

    Attitudes of football fans in lower league Objectives: The aim of the work is to find out the attitudes and motives of people to active visitation of football matches in lower league. Then I would like to introdukce a gained knowledges to the head of the clubs in order to reach a higher level of satisfaction of fans. Methods: Questionnaire, interview Results: It will find out the attitudes of fans in lower leagues thanks to mentioned methods of research. The work will present the view of indi...

  5. Activation of high-elevation alluvial fans in the Transantarctic Mountains - a proxy for warmth along East Antarctic ice margins

    Science.gov (United States)

    Zamora, F. J.; Lewis, A.; Lepper, K. E.

    2012-12-01

    We examined alluvial fans in the McMurdo Dry Valleys region of the Transantarctic Mountains as a proxy for melt-water production along terrestrial margins of the East Antarctic Ice Sheet. Although melting of ice and snow below about 500 m produces large fans, those with catchments above 1000 m are small and show no evidence for recent surface water flow. Well-developed polygonal patterned ground crosscuts relict channels on fan surfaces indicating that inactivity extends back decades to centuries. This suggests that high-elevation fans record only rare sedimentation events resulting from climatic warmth. A record of melt-water production from these alluvial fans combined with regional climate models will help identify temperature and insolation thresholds needed to produce zones of surface melting on the adjacent ice sheet. This is of critical importance because the IPCC identifies ice surface melting along Antarctic margins as the most poorly understood input in models of future sea-level rise. To create a record of melting events we analyzed six alluvial fans; all with catchments above 1000 m. We focused on internal stratigraphy to identify discreet melt events and on fan catchment area, elevation profile and aspect using GIS analysis. We sampled individual beds to determine depositional ages using optically stimulated luminescence (OSL) dating. The six studied fans consist primarily of well-sorted, cross-bedded gravelly sand with less common interbeds of poorly bedded cobbles in a sandy matrix; total sediment thickness ranged from 0.3 to 1.4 m. Sedimentary textures show that fan-building processes are predominantly fluvial sheet flows and dilute debris flows. Beneath each fan are buried desert pavements comprised of ventifacted clasts. These buried surfaces always separate fan sediments from underlying Miocene-age tills. No ventifacted surfaces were observed within fans suggesting that each of the six sampled fans date to discreet periods of sedimentation

  6. Late Quaternary alluvial fans of Emli Valley in the Ecemiş Fault Zone, south central Turkey: Insights from cosmogenic nuclides

    Science.gov (United States)

    Akif Sarıkaya, M.; Yıldırım, Cengiz; Çiner, Attila

    2015-01-01

    Alluvial fans within the paraglacial Ecemiş River drainages on the Aladağlar Mountains in south central Turkey were studied using geomorphological, sedimentological, and chlorine-36 terrestrial cosmogenic nuclide (TCN) surface exposure dating methods to examine the timing of alluvial fan abandonment/incision, and to understand the role of climatic and tectonic processes in the region. These alluvial fan complexes are among the best-preserved succession of alluvial fans in Turkey and they were offset by the major strike-slip Ecemiş Fault of the Central Anatolian Fault Zone. The alluvial fans are mostly composed of well-lithified limestone cobbles (5 to 25 cm in size), and comprise crudely stratified thick beds with a total thickness reaching up to about 80 m. TCN surface exposure dating indicates that the oldest alluvial fan surface (Yalak Fan) was likely formed and subsequently abandoned latest by 136.0 ± 23.4 ka ago, largely on the transition of the Penultimate Glaciation (Marine Isotope Stage 6, MIS 6) to the Last Interglacial (MIS 5) (i.e. Termination II). The second set of alluvial fan (Emli Fan) was possibly developed during the Last Interglacial (MIS 5), and incised twice by between roughly 97.0 ± 13.8 and 81.2 ± 13.2 ka ago. A younger alluvial fan deposit placed on relatively older erosional terraces of the Emli Fan suggests that it may have been produced during the Last Glacial Cycle (MIS 2). These events are similar to findings from other fluvial and lacustrine deposits throughout central Anatolia. The incision times of the Ecemiş alluvial fan surfaces largely coincide with major climatic shifts from the cooler glacial periods to warmer interglacial/interstadial conditions. This indicates that alluvial fans were produced by outwash sediments of paleoglaciers during cooler conditions, and, later, when glaciers started to retreat due to a major warming event, the excess water released from the glaciers incised the pre-existing fan surfaces. An

  7. PICNIC - FANS, ULTRAS AND HOOLIGANS - INTERNAL DIFFERENTIATE OF SUBCULTURE GROUP FOOTBALL FANS IN POLAND

    Directory of Open Access Journals (Sweden)

    Maciej Solinski

    2006-01-01

    Full Text Available This article is a main part of "Internal differentiate of subculture group of football fans in Poland" project. Author has tried to show how the subculture of football fans can be differentiate. Author ha presented three different subgroups of Polish fans. It is very important to divide this subculture, because each subgroup has different mentality and style. That is why I have paid the most attention on this element.

  8. Basement and climate controls on proximal depositional systems in continental settings

    NARCIS (Netherlands)

    Ventra, D.

    2011-01-01

    This doctoral dissertation discusses the sedimentology and dynamics of selected, modern and ancient clastic depositional systems (alluvial fans and colluvial aprons) at continental basin margins. The focus on single depositional systems gave the opportunity to devote particular attention to

  9. Tectonic Uplift and Fan Delta Incision along the Conway Coast, NZ

    Science.gov (United States)

    Burtt, D. G.; Bassett, K. N.

    2015-12-01

    The Conway Coast features a unique confluence of fan deltas, terrace uplift, and transpressional faulting. Thrust faults have caused the uplift of the Hawkeswood Range which provides sediment sources for local Gilbert-type fan deltas uplifting to form terraces. Sediments are characterized by steeply dipping foreset beds, horizontal topset beds and tangential bottomset beds. These fan deltas tend to form on steep basin margins often associated with extensional faulting. However, the Conway coast is dominated by thrust faulting. The Rafa terrace, dated between 52.4±4.5 and 79.0±3.5 ka with Optically Stimulated Luminescence, is exposed in cliff faces on the beach. Local creek channels deposited the fan deltas and later incised older deposits to reveal a three-dimensional perspective of the fan delta. This perspective is vital to the recreation of the fan delta position and channel avulsion, leading to a better understanding of the role of uplift superimposed by sea level change in the formation of the terraces. Forty-three photographs were stitched together to form an extensive photomosaic. The types of sediments, significant structures and relationships between adjacent beds were noted and analyzed. Correlations between the sedimentary architecture and sea level change were made using a sea level curve of the South Pacific over the last 140 ka. The incision of mud by gravel producing large flame structures suggests that there was a drop in sea level and a subsequent progradation of the fan delta. Based on the sea level curve, this drop occurred between ~66-79 ka. Higher in the fan delta, a fining-upward sequence points to a rise in sea level. This correlates with a rise on the sea level curve between ~52-63 ka. Upsection there is another coarsening-upward sequence of 5-10 m thick beds suggesting a fall in sea level before the uplift and incision of the terrace and the subsequent formation of the Ngaroma terrace. Due to their lateral extent, the gravels seem to

  10. Magnetic anomalies in Central Bengal fan

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, T.C.S.; Lakshminarayana, S.; Sarma, K.V.L.N.S.

    Total magnetic field anomalies recorded over the Central Bengal Fan are analysed and the depths to the magnetic basement are computed using the analytical signal and the Werner deconvolution methods. To the west and east of 85 degrees E...

  11. Synchronous and Cogged Fan Belt Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, D.; Dean, J.; Acosta, J.

    2014-02-01

    The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

  12. Mexican Fan Palm - Orange Co. [ds350

    Data.gov (United States)

    California Department of Resources — This dataset provides the known distribution of Mexican fan palm (Washingtonia robusta) in southern Orange County. The surveys were conducted from May to June, 2007...

  13. Quiet, High-Efficiency Vaneaxial Fans Project

    Data.gov (United States)

    National Aeronautics and Space Administration — During this Phase I effort, CRG proposes to demonstrate the ability to significantly reduce the acoustic signature of vaneaxial fans by establishing quiet...

  14. NASA ISS Portable Fan Assembly Acoustics

    Science.gov (United States)

    Boone, Andrew; Allen, Christopher S.; Hess, Linda F.

    2018-01-01

    The Portable Fan Assembly (PFA) is a variable speed fan that can be used to provide additional ventilation inside International Space Station (ISS) modules as needed for crew comfort or for enhanced mixing of the ISS atmosphere. This fan can also be configured with a Shuttle era lithium hydroxide (LiOH) canister for CO2 removal in confined areas partially of fully isolated from the primary Environmental Control and Life Support System (ECLSS) on ISS which is responsible for CO2 removal. This report documents noise emission levels of the PFA at various speed settings and configurations. It also documents the acoustic attenuation effects realized when circulating air through the PFA inlet and outlet mufflers and when operating in its CO2 removal configuration (CRK) with a LiOH canister (sorbent bed) installed over the fan outlet.

  15. How to do things with fan subs: Media engagement as subcultural capital in anime fan subbing

    Directory of Open Access Journals (Sweden)

    Douglas Schules

    2014-09-01

    Full Text Available Anime fandom has been a fairly constant subject in fan scholarship, although only recently have conversations about fan subbing begun to circulate. As useful as those conversations are, none have directly dealt either with the mechanisms of fan subbing, particularly the use of linear notes, as a practice or with how these subs intersect with the flows of subcultural capital. Fan subbing, both as a productive and a consumptive practice, plays a small but influential part in subcultural capital. Engagement with media is a compositional element of such capital in this community.

  16. Active Vibration Reduction of Titanium Alloy Fan Blades (FAN1) Using Piezoelectric Materials

    Science.gov (United States)

    Choi, Benjamin; Kauffman, Jeffrey; Duffy, Kirsten; Provenza, Andrew; Morrison, Carlos

    2010-01-01

    The NASA Glenn Research Center is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this paper, a digital resonant control technique emulating passive shunt circuits is used to demonstrate vibration reduction of FAN1 Ti real fan blade at the several target modes. Single-mode control and multi-mode control using one piezoelectric material are demonstrated. Also a conceptual study of how to implement this digital control system into the rotating fan blade is discussed.

  17. Experiencing Fan Activism: Understanding the Power of Fan Activist Organizations through Members' Narratives

    National Research Council Canada - National Science Library

    Kligler-Vilenchik, Neta; McVeigh-Schultz, Joshua; Weitbrecht, Christine; Tokuhama, Chris

    2012-01-01

    .... Building on 40 interviews with members of two organizations representing different configurations of fan activism, this article discusses three emerging elements that are key to the experience...

  18. Being of service: "X-Files" fans and social engagement

    Directory of Open Access Journals (Sweden)

    Bethan Jones

    2012-06-01

    Full Text Available I explore the ways in which celebrity charity and fan activism can lead to civic engagement and social change. Fan studies has moved away from the traditional view of fans as psychologically deficient and has begun to examine resistance within the cultural productions of fandom—fan fiction, for example, addressing gender imbalances in popular TV shows. However, scholarship on celebrity-focused fans still retains much of the stigmatizing language that mars early writing about fans. I examine the relationship between celebrity and fan; examine the role celebrity plays in framing fan charity; assess how fan investment affects celebrity charity work; and argue that fans are active participants in encouraging social awareness and charitable giving.

  19. Erosion and deposition by supercritical density flows during channel avulsion and backfilling: Field examples from coarse-grained deepwater channel-levée complexes (Sandino Forearc Basin, southern Central America)

    Science.gov (United States)

    Lang, Jörg; Brandes, Christian; Winsemann, Jutta

    2017-03-01

    Erosion and deposition by supercritical density flows can strongly impact the facies distribution and architecture of submarine fans. Field examples from coarse-grained channel-levée complexes from the Sandino Forearc Basin (southern Central America) show that cyclic-step and antidune deposits represent common sedimentary facies of these depositional systems and relate to the different stages of avulsion, bypass, levée construction and channel backfilling. During channel avulsion, large-scale scour-fill complexes (18 to 29 m deep, 18 to 25 m wide, 60 to > 120 m long) were incised by supercritical density flows. The multi-storey infill of the large-scale scour-fill complexes comprises amalgamated massive, normally coarse-tail graded or widely spaced subhorizontally stratified conglomerates and pebbly sandstones, interpreted as deposits of the hydraulic-jump zone of cyclic steps. The large-scale scour-fill complexes can be distinguished from small-scale channel fills based on the preservation of a steep upper margin and a coarse-grained infill comprising mainly amalgamated hydraulic-jump zone deposits. Channel fills include repeated successions deposited by cyclic steps with superimposed antidunes. The deposits of the hydraulic-jump zone of cyclic steps comprise regularly spaced scours (0.2 to 2.6 m deep, 0.8 to 23 m long) infilled by intraclast-rich conglomerates or pebbly sandstones, displaying normal coarse-tail grading or backsets. These deposits are laterally and vertically associated with subhorizontally stratified, low-angle cross-stratified or sinusoidally stratified sandstones and pebbly sandstones, which were deposited by antidunes on the stoss side of the cyclic steps during flow re-acceleration. The field examples indicate that so-called spaced stratified deposits may commonly represent antidune deposits with varying stratification styles controlled by the aggradation rate, grain-size distribution and amalgamation. The deposits of small-scale cyclic

  20. Wordplay, mindplay: Fan fiction and postclassical narratology

    Directory of Open Access Journals (Sweden)

    Veerle Van Steenhuyse

    2014-09-01

    Full Text Available Recent narrative theories on story worlds, or the worlds evoked by narratives, call attention to the process of fan reading and the role which the canon plays in that process. This paper posits that such theories can help us understand literary techniques that make a difference on the level of the reading experience that is implied by fan fiction texts. This is illustrated with a close reading of Naguabo's "The Mother of All Marriage Proposals," a Jane Austen fic.

  1. Aerodynamic modelling and optimization of axial fans

    Energy Technology Data Exchange (ETDEWEB)

    Noertoft Soerensen, Dan

    1998-01-01

    A numerically efficient mathematical model for the aerodynamics of low speed axial fans of the arbitrary vortex flow type has been developed. The model is based on a blade-element principle, whereby the rotor is divided into a number of annular stream tubes. For each of these stream tubes relations for velocity, pressure and radial position are derived from the conservation laws for mass, tangential momentum and energy. The equations are solved using the Newton-Raphson methods, and solutions converged to machine accuracy are found at small computing costs. The model has been validated against published measurements on various fan configurations, comprising two rotor-only fan stages, a counter-rotating fan unit and a stator-rotor stator stage. Comparisons of local and integrated properties show that the computed results agree well with the measurements. Optimizations have been performed to maximize the mean value of fan efficiency in a design interval of flow rates, thus designing a fan which operates well over a range of different flow conditions. The optimization scheme was used to investigate the dependence of maximum efficiency on 1: the number of blades, 2: the width of the design interval and 3: the hub radius. The degree of freedom in the choice of design variable and constraints, combined with the design interval concept, provides a valuable design-tool for axial fans. To further investigate the use of design optimization, a model for the vortex shedding noise from the trailing edge of the blades has been incorporated into the optimization scheme. The noise emission from the blades was minimized in a flow rate design point. Optimizations were performed to investigate the dependence of the noise on 1: the number of blades, 2: a constraint imposed on efficiency and 3: the hub radius. The investigations showed, that a significant reduction of noise could be achieved, at the expense of a small reduction in fan efficiency. (EG) 66 refs.

  2. Australian Queer Science Fiction Fans.

    Science.gov (United States)

    Kerry, Stephen Craig

    2017-10-23

    Science fiction (sf) does more than provide a fleeting moment of entertainment; it has many personal and social functions. In addition to offering audiences "romantic escapism" (Gerrold, 1996, pp. 5-6), sf also enables the "postulation of an alternative reality from which to contemplate this one" (Gerrold, 1996, pp. 5-6); as such, it is especially important "for groups which have had limited stakes in the status quo" (Jenkins, 1995, p. 242). To date, no research has been undertaken on the relationship between Australian queers and sf fandom. This article reports the findings of an online survey and explores the psycho-social features of Australian queer sf fans and why they like the genre. While the characteristics of this sample mirror those of Australian queers generally, they also have slightly higher rates of mental illness and are far more likely to state they have "no religion." Furthermore, while enjoying the "sciency" (P10, bisexual woman) aspects of sf, Australian queers also like the "poignant metaphors for our own civilization" (P45, asexual man).

  3. Decoding sediment transport dynamics on alluvial fans from spatial changes in grain size, Death Valley, California

    Science.gov (United States)

    Brooke, Sam; Whittaker, Alexander; Watkins, Stephen; Armitage, John

    2017-04-01

    How fluvial sediment transport processes are transmitted to the sedimentary record remains a complex problem for the interpretation of fluvial stratigraphy. Alluvial fans represent the condensed sedimentary archive of upstream fluvial processes, controlled by the interplay between tectonics and climate over time, infused with the complex signal of internal autogenic processes. With high sedimentation rates and near complete preservation, alluvial fans present a unique opportunity to tackle the problem of landscape sensitivity to external boundary conditions such as climate. For three coupled catchments-fan systems in the tectonically well-constrained northern Death Valley, we measure grain size trends across well-preserved Holocene and Late-Pleistocene deposits, which we have mapped in detail. Our results show that fan surfaces from the Late-Pleistocene are, on average, 50% coarser than counterpart active or Holocene fan surfaces, with clear variations in input grain sizes observed between surfaces of differing age. Furthermore, the change in ratio between mean grain size and standard deviation is stable downstream for all surfaces, satisfying the statistical definition of self-similarity. Applying a self-similarity model of selective deposition, we derive a relative mobility function directly from our grain size distributions, and we evaluate for each fan surface the grain size for which the ratio of the probability of transport to deposition is 1. We show that the "equally mobile" grain size lies in the range of 20 to 35 mm, varies over time, and is clearly lower in the Holocene than in the Pleistocene. Our results indicate that coarser grain sizes on alluvial fans are much less mobile than in river systems where such an analysis has been previously applied. These results support recent findings that alluvial fan sediment characteristics can be used as an archive of past environmental change and that landscapes are sensitive to environmental change over a glacial

  4. Psychological Implications for Submarine Display Design

    Science.gov (United States)

    2005-08-01

    This paper addresses a number of psychological issues pertaining to display design . We review the literature comparing 3-D and 2-D displays and...perceptual, cognitive and ecological factors that are relevant to display design for submarine environments. The Generative Transformational approach...to visual perception is outlined and the relevance of transformational theory to display design is discussed. The paper also discusses a number of

  5. Elemental mercury at submarine hydrothermal vents in the Bay of Plenty, Taupo volcanic zone, New Zealand

    Science.gov (United States)

    Stoffers, P.; Hannington, M.; Wright, I.; Herzig, P.; de Ronde, C.; Scientific Party, Shipboard

    1999-10-01

    Hot springs in active geothermal areas such as Yellowstone National Park, the Geysers geothermal field in California, and the Taupo volcanic zone in New Zealand are notably enriched in the trace metals Au, Ag, As, Sb, and Hg. Such near-surface hot springs have formed many of the world's important deposits of gold and silver and some of the largest deposits of mercury. The majority of these are associated with continental geothermal systems in subaerial environments. Here we report the discovery of active mercury-depositing hot springs in a submarine setting, at nearly 200 m water depth, within the offshore extension of the Taupo volcanic zone of New Zealand. These vents contain the first documented occurrence of elemental mercury on the sea floor and provide an important link between offshore hydrothermal activity and mercury-depositing geothermal systems on land. The discovery has implications for mercury transport in sea-floor hydrothermal systems and underscores the importance of submarine volcanic and geothermal activity as a source of mercury in the oceans.

  6. Topology Model of the Flow around a Submarine Hull Form

    Science.gov (United States)

    2015-12-01

    resistance and flow noise arising from flow-structure interaction, it is necessary to test the shape of the submarine , which includes the length-to...UNCLASSIFIED Topology Model of the Flow around a Submarine Hull Form S.-K. Lee Maritime Division Defence Science and Technology Group DST-Group–TR...3177 ABSTRACT A topology model constructed from surface-streamer visualisation describes the flow around a generic conventional submarine hull form at

  7. A Lanchester model of submarine attack on a carrier battlegroup

    OpenAIRE

    Eagle, James N.

    1987-01-01

    A Lanchester model is developed for a battlegroup ASW engagement. Two variations are included. In the first, long-range missile firing submarines, short-range missile or torpedo firing submarines, and submarines firing only torpedoes distribute their attack uniformly over battlegroup escort ships and carriers. In the second variation, the attack is concentrated on the carriers. supported by the Naval War College http://archive.org/details/lanchestermodelo00eagl NA

  8. Cyclic steps and superimposed antidune deposits: important elements of coarse-grained deepwater channel-levée complexes

    Science.gov (United States)

    Lang, Joerg; Brandes, Christian; Winsemann, Jutta

    2017-04-01

    The facies distribution and architecture of submarine fans can be strongly impacted by erosion and deposition by supercritical density flows. We present field examples from the Sandino Forearc Basin (southern Central America), where cyclic-step and antidune deposits represent important sedimentary facies of coarse-grained channel-levée complexes. These bedforms occur in all sub-environments of the depositional systems and relate to the different stages of avulsion, bypass, levée construction and channel backfilling. Large-scale scours (18 to 29 m deep, 18 to 25 m wide, 60 to >120 m long) with an amalgamated infill, comprising massive, normally coarse-tail graded or spaced subhorizontally stratified conglomerates and pebbly sandstones, are interpreted as deposits of the hydraulic-jump zone of cyclic steps. These cyclic steps probably formed during avulsion, when high-density flows were routed into the evolving channel. The large-scale scour fills can be distinguished from small-scale channel fills based on the preservation of a steep upper margin and a coarse-grained infill comprising mainly amalgamated hydraulic-jump deposits. Channel fills include repetitive successions deposited by cyclic steps with superimposed antidunes. The hydraulic-jump zone of cyclic-step deposits comprises regularly spaced scours (0.2 to 2.6 m deep, 0.8 to 23 m wide), which are infilled by intraclast-rich conglomerates or pebbly sandstones and display normal coarse-tail grading or backsets. Laterally and vertically these deposits are associated with subhorizontally stratified, low-angle cross-stratified or sinusoidal stratified pebbly sandstones and sandstones (wavelength 0.5 to 18 m), interpreted as representing antidune deposits formed on the stoss-side of the cyclic steps during flow re-acceleration. The field examples indicate that so-called crudely or spaced stratified deposits may commonly represent antidune deposits with varying stratification styles controlled by the aggradation

  9. Fan relationship management in football - going beyond traditional product offerings to win the hearts of fans

    DEFF Research Database (Denmark)

    Cortsen, Kenneth

    2015-01-01

    The management and control of fan relations should go beyond a football club’s traditional product and service offerings and touch the important experiential side of the football economy. This will create a stronger platform to optimize ROI, ROE and ROO relating to different fan segments....

  10. Meta-Analysis of Data from the Submarine Ventilation Doctrine Test Program

    National Research Council Canada - National Science Library

    Hoover, J

    1998-01-01

    .... The Submarine Ventilation Doctrine Test Program was developed to address submarine-specific issues regarding the use of ventilation systems to control smoke and heat movement, maintain habitability...

  11. Palynofacies reveal fresh terrestrial organic matter inputs in the terminal lobes of the Congo deep-sea fan

    Science.gov (United States)

    Schnyder, Johann; Stetten, Elsa; Baudin, François; Pruski, Audrey M.; Martinez, Philippe

    2017-08-01

    The Congo deep-sea fan is directly connected to the Congo River by a unique submarine canyon. The Congo River delivers up to 2×1012gPOC/yr, a part of which is funnelled by the submarine canyon and feeds the deep-sea environments. The more distal part of the Congo deep-sea fan, the terminal lobe area, has a surface of 2500 km2 and is situated up to 800 km offshore at depths of 4750-5000 m. It is a remarkable place to study the fate and distribution of the organic matter transferred from the continent to the deep ocean via turbidity currents. Forty-two samples were analyzed from the terminal lobes, including sites from the active channel, one of its levees and an abandoned distal channel. Samples were collected using multitube cores and push-cores using a Victor 6000 ROV, which surveyed the dense chemosynthetic habitats that locally characterize the terminal lobes. Palynofacies reveal a remarkably well-preserved, dominantly terrestrial particulate organic matter assemblage, that has been transferred from the continent into the deep-sea by turbidity currents. Delicate plant structures, cuticle fragments and plant cellular material is often preserved, highlighting the efficiency of turbidity currents to transfer terrestrial organic matter to the sea-floor, where it is preserved. Moreover, the palynofacies data reveal a general sorting by density or buoyancy of the organic particles, as the turbulent currents escaped the active channel, feeding the levees and the more distal, abandoned channel area. Finally, in addition to aforementioned hydrodynamic factors controlling the organic matter accumulation, a secondary influence of chemosynthetic habitats on organic matter preservation is also apparent. Palynofacies is therefore a useful tool to record the distribution of organic matter in recent and ancient deep-sea fan environments, an important topic for both academic and petroleum studies.

  12. Introduction of a Cooling-Fan Efficiency Index

    DEFF Research Database (Denmark)

    Schiavon, S.; Melikov, Arsen Krikor

    2009-01-01

    , while cooling capacity and efficiency of energy use are unknown. To address this knowledge gap, this paper introduces the cooling-fan efficiency (CFE) index, defined as the ratio between the cooling effect (measured with a thermal manikin) generated by the device and its power consumption. The index...... cooling effect and an index for determining fan efficiency, such as the CFE index proposed in this study, need to be developed. The cooling fans generate a nonuniform velocity field around occupants, which cannot be described with a single air-velociry value. Therefore, it is not clear how to apply...... was determined for a ceiling fan, a desk fan, standing fan, and a tower fan in a real office at three room air temperatures and at different fan speed levels. The results reveal that the index is sensitive enough to identify differences in the performance of the cooling devices. A standard method for testing fan...

  13. A new model for turbidity current behavior based on integration of flow monitoring and precision coring in a submarine canyon

    Science.gov (United States)

    Symons, William O.; Sumner, Esther J.; Paull, Charles K.; Cartigny, Matthieu J.B.; Xu, Jingping; Maier, Katherine L.; Lorenson, Thomas; Talling, Peter J.

    2017-01-01

    Submarine turbidity currents create some of the largest sediment accumulations on Earth, yet there are few direct measurements of these flows. Instead, most of our understanding of turbidity currents results from analyzing their deposits in the sedimentary record. However, the lack of direct flow measurements means that there is considerable debate regarding how to interpret flow properties from ancient deposits. This novel study combines detailed flow monitoring with unusually precisely located cores at different heights, and multiple locations, within the Monterey submarine canyon, offshore California, USA. Dating demonstrates that the cores include the time interval that flows were monitored in the canyon, albeit individual layers cannot be tied to specific flows. There is good correlation between grain sizes collected by traps within the flow and grain sizes measured in cores from similar heights on the canyon walls. Synthesis of flow and deposit data suggests that turbidity currents sourced from the upper reaches of Monterey Canyon comprise three flow phases. Initially, a thin (38–50 m) powerful flow in the upper canyon can transport, tilt, and break the most proximal moorings and deposit chaotic sands and gravel on the canyon floor. The initially thin flow front then thickens and deposits interbedded sands and silty muds on the canyon walls as much as 62 m above the canyon floor. Finally, the flow thickens along its length, thus lofting silty mud and depositing it at greater altitudes than the previous deposits and in excess of 70 m altitude.

  14. Sedimentology of latero-frontal moraines and fans on the west coast of South Island, New Zealand

    Science.gov (United States)

    Evans, David J. A.; Shulmeister, James; Hyatt, Olivia

    2010-12-01

    Exposures through the LGM latero-frontal moraine loops at sites along the west coast of South Island, New Zealand reveal a depositional environment that was dominated by the progradation of steep fronted, debris flow-fed fans, manifest in crudely stratified to massive diamictons, arranged in sub-horizontal to steeply dipping clinoforms and containing discontinuous bodies of variably sorted, stratified sediment (LFA 1). The fans were constructed by debris-covered glaciers advancing over outwash plains, as recorded by well stratified and horizontally bedded gravels, sands and diamicts (LFA 0). The ice-contact slopes of the fans are offlapped by retreat phase deposits in the form of glacilacustrine depo-centres (LFA 2), which record the existence of moraine-dammed lakes. Interdigitation of lake rhythmites and subaerial to subaqueous sediment gravity flow deposits documents intense debris-flow activity on unstable moraine/fan surfaces. Glacier readvances in all catchments are documented by glacitectonic disturbance and localized hydrofracturing of LFA 2, followed by the emplacement of schist-dominated debris flow-fed fans (LFA 3) inside and over the top of the earlier latero-frontal moraine/fan loops. Contorted and disturbed bedding in LFA 3 reflects its partial deposition in supraglacial positions. Clast lithologies in LFAs 1 and 3 reveal that two distinct transport pathways operated during moraine construction, with an early period of latero-frontal fan construction involving mixed lithologies and a later period of ice-contact/supraglacial fan construction dominated by schist lithologies from the mountains. These two periods of deposition were separated by a period of moraine abandonment and paraglacial reworking of ice-contact slopes to produce LFA 2. The occurrence of LFA 3 at all sites indicates that the glacier readvance phase responsible for its deposition was not localized or glacier-specific, and involved the transfer of large volumes of schist, possibly due

  15. Australia’s Submarine Design Capabilities and Capacities: Challenges and Options for the Future Submarine

    Science.gov (United States)

    2011-01-01

    General Dynamics Electric Boat Corporation EMC electromagnetic compatibility EMF electromagnetic field EMI electromagnetic interference EPCM engineering...to-diagnose flow-induced radiated noise Own-sensor performance degradation Note: Risks can be reduced for given designs using scale models...Acoustic analysis Addresses the total radiated noise signature of submarine designs Radiated noise that an enemy might detect Self-noise that that

  16. Quantifying sediment dynamics on alluvial fans, Iglesia basin, south Central Argentine Andes

    Science.gov (United States)

    Harries, Rebekah; Kirstein, Linda; Whittaker, Alex; Attal, Mikael; Peralta, Silvio

    2017-04-01

    Qualitative interpretations of environmental change drawn from alluvial fan stratigraphy typically tie the deposition of greater volumes of coarser sediment to wetter climatic periods. For example, step changes in sediment flux and discharge associated with glacial-interglacial cycles are often linked to the progradation and back stepping of a fan's toe (Harvey et al, 2002). Indeed, more recent quantitative stratigraphic models demonstrate changes in the volume and calibre of sediment fluxed from an uplifted catchment can produce predictable shifts in the rate at which fluvial deposits fine downstream (Duller et al. 2010, Armitage et al. 2011). These interpretations, however, make three important assumptions: 1) the volume and calibre of the sediment transferred from an eroding mountain belt to a depositional basin is directly related to climate through some value of time-averaged discharge or catchment wetness; 2) lateral sources of sediment, such as tributaries, do not significantly influence the pattern of deposition in a basin and, similarly, 3) the reworking of older fan surfaces is minimal and does not impact the depositional pattern of younger deposits. Here we demonstrate each of these assumptions underestimates the importance of variance in transportable grain sizes in influencing the local and basin-wide deposited grain size trends. Using the Iglesia basin in the Argentine south Central Andes as a natural laboratory, we compare three large, adjacent, alluvial fan systems whose catchments experience the same background tectonic and climatic forcing. We find regional climate forcing is not expressed uniformly in the downstream grain size fining rates of their modern systems. Furthermore, we observe the variance in transportable grain sizes supplied from each primary catchment and the variance of material introduced by tributaries and fan surfaces downstream can act as first order controls on the rate of downstream fining. We also raise the importance of

  17. Optimism Bias in Fans and Sports Reporters

    Science.gov (United States)

    Love, Bradley C.

    2015-01-01

    People are optimistic about their prospects relative to others. However, existing studies can be difficult to interpret because outcomes are not zero-sum. For example, one person avoiding cancer does not necessitate that another person develops cancer. Ideally, optimism bias would be evaluated within a closed formal system to establish with certainty the extent of the bias and the associated environmental factors, such that optimism bias is demonstrated when a population is internally inconsistent. Accordingly, we asked NFL fans to predict how many games teams they liked and disliked would win in the 2015 season. Fans, like ESPN reporters assigned to cover a team, were overly optimistic about their team’s prospects. The opposite pattern was found for teams that fans disliked. Optimism may flourish because year-to-year team results are marked by auto-correlation and regression to the group mean (i.e., good teams stay good, but bad teams improve). PMID:26352146

  18. MOTIVATION FOR INDIVIDUALS’ INVOLVEMENT WITH FAN PAGES

    Directory of Open Access Journals (Sweden)

    Willy Abdillah

    2016-05-01

    Full Text Available This research examines the empirical model of individuals’ involvement with fan pages. The research model was developed based on the social influence factors and the brand post popularity model. The research employed an online survey questionnaire. 300 samples were collected by using a purposive sampling technique, and analyzed using the Partial Least Square (PLS method. The results showed that identification, interactivity, informational content and valence of comment were the motivating factors for the intent to become involved with fan pages. It was indicated that the brand popularity model was not the only relevant model to explain the social computing phenomenon in the context of fan pages, but social influence factors also play a part. The implications for stakeholders and further research are discussed.

  19. SWITCHING POWER FAN CONTROL OF COMPUTER

    Directory of Open Access Journals (Sweden)

    Oleksandr I. Popovskyi

    2010-10-01

    Full Text Available Relevance of material presented in the article, due to extensive use of high-performance computers to create modern information systems, including the NAPS of Ukraine. Most computers in NAPS of Ukraine work on Intel Pentium processors at speeds from 600 MHz to 3 GHz and release a lot of heat, which requires the installation of the system unit 2-3 additional fans. The fan is always works on full power, that leads to rapid deterioration and high level (up to 50 dB noise. In order to meet ergonomic requirements it is proposed to іnstall a computer system unit and an additional control unit ventilators, allowing independent control of each fan. The solution is applied at creation of information systems planning research in the National Academy of Pedagogical Sciences of Ukraine on Internet basis.

  20. North Sea submarine cable disruptions and fishing activity

    NARCIS (Netherlands)

    Hintzen, N.T.; Machiels, M.A.M.

    2014-01-01

    At the North Sea seafloor, numerous submarine cables are positioned that connect telecommunication networks between countries. Worldwide, human activities cause most of the cable disruptions with fisheries accounting for nearly half of all reported faults. Due to a recent increase of submarine cable

  1. Delineation of alluvial fans from Digital Elevation Models with a GIS algorithm for the geomorphological mapping of the Earth and Mars

    Science.gov (United States)

    Norini, Gianluca; Zuluaga, Maria Clara; Ortiz, Iris Jill; Aquino, Dakila T.; Lagmay, Alfredo Mahar F.

    2016-11-01

    Alluvial fans are prominent depositional geomorphic features present in nearly all global climates on Earth, and also found on Mars. In this study, we present a Geographic Information System (GIS) algorithm designed for the semi-automated detection of alluvial fans that are connected to their contributing upstream drainage network, from the analysis of Digital Elevation Models (DEMs). Through a combination of spatial analysis procedures, the GIS algorithm generates maps of alluvial fans and their upstream source drainage and watersheds. Tests of the algorithm in areas with well-known alluvial fans indicate that this new GIS procedure is capable of high-accuracy mapping of the fan apexes and correct delineation of fan deposits, in both arid and humid climates. Possible future applications of the GIS algorithm presented in this study include the systematic survey of alluvial fans at the local, regional and planetary scales, important for geologic hazard assessment, studies on the evolution of climate, analysis of continental sedimentary environments, understanding of the interplay between the endogenous dynamics and exogenous processes, and the evaluation of natural resources.

  2. Homophobia, heteronormativity, and slash fan fiction

    Directory of Open Access Journals (Sweden)

    April S. Callis

    2016-09-01

    Full Text Available I analyze the relationship between homophobia/heteronormativity and slash fan fiction. Through reading and coding almost 6,000 pages of Kirk/Spock fan fiction written from 1978 to 2014, I illuminate shifts in how normative gender and sexuality are portrayed by K/S authors. Writers of K/S, while ostensibly writing about the 23rd century, consciously or unconsciously include cultural norms from the 20th and 21st centuries. Thus, slash becomes a lens through which readers can view a decrease in both homophobia and heteronormativity in US culture over the past several decades.

  3. Aerodynamic Modelling and Optimization of Axial Fans

    DEFF Research Database (Denmark)

    Sørensen, Dan Nørtoft

    A numerically efficient mathematical model for the aerodynamics oflow speed axial fans of the arbitrary vortex flow type has been developed.The model is based on a blade-element principle, whereby therotor is divided into a number of annular streamtubes.For each of these streamtubes relations...... and integrated propertiesshow that the computed results agree well with the measurements.Integrating a rotor-only version of the aerodynamic modelwith an algorithm for numerical designoptimization, enables the finding of an optimum fan rotor.The angular velocity of the rotor, the hub radius and the spanwise...

  4. The 1929 Grand Banks submarine landslide revisited

    Science.gov (United States)

    Schulten, Irena; Mosher, David C.; Krastel, Sebastian; Piper, David J. W.; Kienast, Markus

    2017-04-01

    On November 18th, 1929 a large submarine landslide occurred along the St. Pierre Slope of the southwestern Grand Banks of Newfoundland, as a result of a Mw 7.2 earthquake. This submarine landslide led to the first recognition of naturally-occurring submarine turbidity currents and is one of the few landslides known to have generated a tsunami. The event caused 28 causalities in Newfoundland and severe infrastructural damage. Earlier investigations of the area identified widely distributed shallow mass failures (15 - 20 m high escarpments), but no evidence of a larger headscarp. It is difficult to conceive, therefore, how this distributed shallow failure that rapidly evolved into a turbidity current would have generated a tsunami. It is hypothesised in this study that a deeper rooted sediment failure ( 500 m), involving faulting and mass-rotation, was involved in the sediment failure and this displacement generated the tsunami. In order to test this hypothesis, the volume and kinematics of the 1929 slope failure are analysed by means of recently acquired high resolution seismic reflection and multibeam swath bathymetry data, in addition to a significant volume of legacy data. The data allow determination of: 1) the dimension of the failure area, 2) the thickness and volume of failed sediment on St. Pierre Slope, 3) fault patterns and displacements, and 4) styles of sediment failure involved. Shallow (20 m high) sinuous escarpments and a number of faults are observed along the upper St. Pierre Slope (500 - 2 500 m water depth). The uppermost and largest of these escarpments shows association with a fault system. Preliminary results, therefore, indicate a complex sediment failure pattern along the St. Pierre Slope, possibly involving a deep-seated decollement and mobilization of a large volume of surficial sediment through retrogressive failure. Causes for the tsunami are yet to be determined.

  5. Multivariable Control System Design for a Submarine,

    Science.gov (United States)

    1984-05-01

    perturbations applied to the nominal point were identical in all cases (see table 2.3). The comparisons show excellent correlation between the...Open Loop Singular Values for the 5 and 1S Knot Linear Modelo *~~* b % % V’ , * % ~ .%~ C 9 ~ V. --.- V. V.-.--.--46..- S. 77’ Model S20R5 20- 10- -0...without imparting a pitch angle to the submarine and provides an excellent example of both the usefulness of w(t) as a state variable and the

  6. Hydrogen isotope systematics of submarine basalts

    Science.gov (United States)

    Kyser, T.K.; O'Neil, J.R.

    1984-01-01

    The D/H ratios and water contents in fresh submarine basalts from the Mid-Atlantic Ridge, the East Pacific Rise, and Hawaii indicate that the primary D/H ratios of many submarine lavas have been altered by processes including (1) outgassing, (2) addition of seawater at magmatic temperature, and (3) low-temperature hydration of glass. Decreases in ??D and H2O+ from exteriors to interiors of pillows are explained by outgassing of water whereas inverse relations between ??D and H2O+ in basalts from the Galapagos Rise and the FAMOUS Area are attributed to outgassing of CH4 and H2. A good correlation between ??D values and H2O is observed in a suite of submarine tholeiites dredged from the Kilauea East Rift Zone where seawater (added directly to the magma), affected only the isotopic compositions of hydrogen and argon. Analyses of some glassy rims indicate that the outer millimeter of the glass can undergo lowtemperature hydration by hydroxyl groups having ??D values as low as -100. ??D values vary with H2O contents of subaerial transitional basalts from Molokai, Hawaii, and subaerial alkali basalts from the Society Islands, indicating that the primary ??D values were similar to those of submarine lavas. Extrapolations to possible unaltered ??D values and H2O contents indicate that the primary ??D values of most thoteiite and alkali basalts are near -80 ?? 5: the weight percentages of water are variable, 0.15-0.35 for MOR tholeiites, about 0.25 for Hawaiian tholeiites, and up to 1.1 for alkali basalts. The primary ??D values of -80 for most basalts are comparable to those measured for deep-seated phlogopites. These results indicate that hydrogen, in marked contrast to other elements such as Sr, Nd, Pb, and O, has a uniform isotopic composition in the mantle. This uniformity is best explained by the presence of a homogeneous reservoir of hydrogen that has existed in the mantle since the very early history of the Earth. ?? 1984.

  7. Fan fiction metadata creation and utilization within fan fiction archives: Three primary models

    Directory of Open Access Journals (Sweden)

    Shannon Fay Johnson

    2014-09-01

    Full Text Available Issues related to searchability and ease of access have plagued fan fiction since its inception. This paper discusses the predominate forms of fan-mediated indexing and descriptive metadata, commonly referred to as folksonomy or tagging, and compares the benefits and disadvantages of each model. These models fall into three broad categories: free tagging, controlled vocabulary, and hybrid folksonomy. Each model has distinct advantages and shortcomings related to findability, results filtering, and creative empowerment. Examples for each are provided. Possible ramifications to fan fiction from improved metadata and access are also discussed.

  8. Experiencing fan activism: Understanding the power of fan activist organizations through members' narratives

    Directory of Open Access Journals (Sweden)

    Neta Kligler-Vilenchik

    2012-06-01

    Full Text Available Fan activism, forms of civic engagement and political participation growing out of experiences of fandom, is a powerful mode of mobilization, particularly for young people. Building on 40 interviews with members of two organizations representing different configurations of fan activism, this article discusses three emerging elements that are key to the experience of membership in such groups. We suggest that the strength of fan activist groups builds on successfully combining these elements: two that are common to fandom, shared media experiences and a sense of community, and one that is traditionally ascribed to volunteerism and activism, the wish to help.

  9. Design and Test of Fan/Nacelle Models Quiet High-Speed Fan

    Science.gov (United States)

    Miller, Christopher J. (Technical Monitor); Weir, Donald

    2003-01-01

    The Quiet High-Speed Fan program is a cooperative effort between Honeywell Engines & Systems (formerly AlliedSignal Engines & Systems) and the NASA Glenn Research Center. Engines & Systems has designed an advanced high-speed fan that will be tested on the Ultra High Bypass Propulsion Simulator in the NASA Glenn 9 x 15 foot wind tunnel, currently scheduled for the second quarter of 2000. An Engines & Systems modern fan design will be used as a baseline. A nacelle model is provided that is characteristic of a typical, modern regional aircraft nacelle and meets all of the program test objectives.

  10. Quiet High Speed Fan II (QHSF II): Final Report

    Science.gov (United States)

    Kontos, Karen; Weir, Don; Ross, Dave

    2012-01-01

    This report details the aerodynamic, mechanical, structural design and fabrication of a Honey Engines Quiet High Speed Fan II (lower hub/tip ratio and higher specific flow than the Baseline I fan). This fan/nacelle system incorporates features such as advanced forward sweep and an advanced integrated fan/fan exit guide vane design that provides for the following characteristics: (1) Reduced noise at supersonic tip speeds, in comparison to current state-of-the-art fan technology; (2) Improved aeroelastic stability within the anticipated operating envelope; and (3) Aerodynamic performance consistent with current state-of-the-art fan technology. This fan was fabricated by Honeywell and tested in the NASA Glenn 9- by 15-Ft Low Speed Wind Tunnel for aerodynamic, aeromechanical, and acoustic performance.

  11. Improving Fan System Performance: A Sourcebook for Industry

    Energy Technology Data Exchange (ETDEWEB)

    2003-04-01

    This is one of a series of sourcebooks on motor-driven equipment produced by the Industrial Technologies Program. It provides a reference for industrial fan systems users, outlining opportunities to improve fan system performance.

  12. Alluvial fan sensitivity to glacial-interglacial climate change: case studies from Death Valley.

    Science.gov (United States)

    Whittaker, Alexander; D'Arcy, Mitch; Roda-Boluda, Duna; Brooke, Sam

    2016-04-01

    The effects of climate change on eroding landscapes and the sedimentary record remain poorly understood. The measurement of regional grain size trends in stream-flow deposits provides one way to address this issue because, in principle, these trends embed important information on the dynamics of sediment routing systems and their sensitivity to external forcings. In many cases, downstream stratigraphic fining is primarily driven by selective deposition of sediment. The relative efficiency of this process is determined by the physical characteristics of the input sediment supply and the spatial distribution of subsidence rate, which generates the accommodation necessary for mass extraction. Here, we measure grain size fining rates from apex to toe for alluvial fan systems in Death Valley, California, which have well-exposed modern and late Pleistocene deposits, where the long-term tectonic boundary conditions are known and where climatic variation over this time period is well-constrained. Our field data demonstrate that input grain sizes and input fining rates do vary noticeably over the late Pleistocene-Holocene period in this study area, although there is little evidence for significant changes in rates of faulting in the last 200 ky. For two catchments in the Grapevine Mountains for which we have excellent stratigraphic constraints on modern and 70 ka fan deposits, we use a self-similarity based grain size fining model to understand changes in sediment flux to the fans over this time period. When calibrated with cosmogenically-derived catchment erosion rates, our results show that a 30 % decrease in average precipitation rate over this time-frame led to a 20 % decrease in sediment flux to the fans, and a clear increase in the down-fan rate of fining. This supports existing landscape evolution models that relate a decrease in precipitation rate to a decrease in sediment flux, but implies that the relationship between sediment flux and precipitation rate may be

  13. Fan action and political participation on "The Colbert Report"

    Directory of Open Access Journals (Sweden)

    Marcus Schulzke

    2012-06-01

    Full Text Available The Colbert Report merges the increasingly popular political satire genre with fan activism. The result is that the fan community helps to construct Colbert's malleable character and demonstrates symbolic power through its willingness to act. The fans are usually a nonpartisan force, acting to produce entertainment rather than substantive political change. However, this can be politically meaningful, as the fans' projects promote collective action, parallel political activities like voting and protesting, and encourage critical thinking about political information.

  14. Patterns of alcohol and drugs consumption in young soccer fans

    OpenAIRE

    Rodrigues, Anelise Lopes; Sarriera, Jorge Castellá

    2016-01-01

    Alcohol and drug consumption among young soccer fans have been associated with violence in soccer context. This study aims to determine patterns of alcohol, marijuana and cocaine consumption in a sample of 1,130 soccer fans residents in the Rio Grande do Sul State, as well as to verify if there are differences regarding gender, age and if the participant is member of organized fan soccer or not. From a questionnaire available through Internet, soccer fan answered the frequency they generally ...

  15. Characterizing Fan Behavior to Study Para Social Breakups

    OpenAIRE

    Garimella, Kiran; Cohen, Jonathan; Weber, Ingmar

    2017-01-01

    Celebrity and fandom have been studied extensively in real life. However, with more and more celebrities using social media, the dynamics of interaction between celebrities and fans has changed. Using data from a set of 57,000 fans for the top followed celebrities on Twitter, we define a wide range of features based on their Twitter activity. Using factor analysis we find the most important factors that underlie fan behavior. Using these factors, we conduct analysis on (i) understanding fan b...

  16. Flow dynamics around downwelling submarine canyons

    Directory of Open Access Journals (Sweden)

    J. M. Spurgin

    2014-10-01

    Full Text Available Flow dynamics around a downwelling submarine canyon were analysed with the Massachusetts Institute of Technology general circulation model. Blanes Canyon (northwestern Mediterranean was used for topographic and initial forcing conditions. Fourteen scenarios were modelled with varying forcing conditions. Rossby and Burger numbers were used to determine the significance of Coriolis acceleration and stratification (respectively and their impacts on flow dynamics. A new non-dimensional parameter (χ was introduced to determine the significance of vertical variations in stratification. Some simulations do see brief periods of upwards displacement of water during the 10-day model period; however, the presence of the submarine canyon is found to enhance downwards advection of density in all model scenarios. High Burger numbers lead to negative vorticity and a trapped anticyclonic eddy within the canyon, as well as an increased density anomaly. Low Burger numbers lead to positive vorticity, cyclonic circulation, and weaker density anomalies. Vertical variations in stratification affect zonal jet placement. Under the same forcing conditions, the zonal jet is pushed offshore in more uniformly stratified domains. The offshore jet location generates upwards density advection away from the canyon, while onshore jets generate downwards density advection everywhere within the model domain. Increasing Rossby values across the canyon axis, as well as decreasing Burger values, increase negative vertical flux at shelf break depth (150 m. Increasing Rossby numbers lead to stronger downwards advection of a passive tracer (nitrate, as well as stronger vorticity within the canyon. Results from previous studies are explained within this new dynamic framework.

  17. Submarine melt rates under Greenland's ice tongues

    Science.gov (United States)

    Wilson, Nat; Straneo, Fiametta; Heimbach, Patrick; Cenedese, Claudia

    2017-04-01

    The few remaining ice tongues (ice-shelf like extensions) of Greenland's glaciers are undergoing rapid changes with potential implications for the stability of the ice sheet. Submarine melting is recognized as a major contributor to mass loss, yet the magnitude and spatial distribution of melt are poorly known or understood. Here, we use high resolution satellite imagery to infer the magnitude and spatial variability of melt rates under Greenland's largest remaining ice tongues: Ryder Glacier, Petermann Glacier and Nioghalvfjerdsbræ (79 North Glacier). We find that submarine plus aerial melt approximately balance the ice flux from the grounded ice sheet for the first two while at Nioghalvfjerdsbræ the total melt flux exceeds the inflow of ice indicating thinning of the ice tongue. We also show that melt rates under the ice tongues vary considerably, exceeding 60 m yr-1 near the grounding zone and decaying rapidly downstream. Channels, likely originating from upstream subglacial channels, give rise to large melt variations across the ice tongues. Using derived melt rates, we test simplified melt parameterizations appropriate for ice sheet models and find the best agreement with those that incorporate ice tongue geometry in the form of depth and slope.

  18. Fan Affinity Laws from a Collision Model

    Science.gov (United States)

    Bhattacharjee, Shayak

    2012-01-01

    The performance of a fan is usually estimated using hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this paper we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour…

  19. Dead links, vaporcuts, and creativity in fan edit replication

    Directory of Open Access Journals (Sweden)

    Joshua Wille

    2015-09-01

    Full Text Available In my examination of a Star Wars prequel trilogy fan edit reportedly made by Topher Grace, I introduce the term vaporcut to describe fan edits with reputations that may generate critical discourse but that are not publicly released. I explore the ways some fan editors attempt to recreate intangible projects but inevitably produce variant works that reflect their own creative perspectives.

  20. Alcohol-Related Fan Behavior on College Football Game Day

    Science.gov (United States)

    Glassman, Tavis; Werch, Chudley E.; Jobli, Edessa; Bian, Hui

    2007-01-01

    High-risk drinking on game day represents a unique public health challenge. Objective: The authors examined the drinking behavior of college football fans and assessed the support for related interventions. Participants: The authors randomly selected 762 football fans, including college students, alumni, and other college football fans, to…

  1. Motivational variables that influence fan attendance in domestic ...

    African Journals Online (AJOL)

    The motivational measures revealed in the study may be used by sport marketers to develop marketing communication strategies in various aspects of fan attendance. From a management perspective the results suggests that greater gains in fan attraction and attendance can be achieved by segmenting the sport fan ...

  2. Environmental assessment of submarine power cables

    Energy Technology Data Exchange (ETDEWEB)

    Isus, Daniel; Martinez, Juan D. [Grupo General Cable Sistemas, S.A., 08560-Manlleu, Barcelona (Spain); Arteche, Amaya; Del Rio, Carmen; Madina, Virginia [Tecnalia Research and Innovation, 20009 San Sebastian (Spain)

    2011-03-15

    Extensive analyses conducted by the European Community revealed that offshore wind energy have relatively benign effects on the marine environment by comparison to other forms of electric power generation [1]. However, the materials employed in offshore wind power farms suffer major changes to be confined to the marine environment at extreme conditions: saline medium, hydrostatic pressure... which can produce an important corrosion effect. This phenomenon can affect on the one hand, to the material from the structural viewpoint and on the other hand, to the marine environment. In this sense, to better understand the environmental impacts of generating electricity from offshore wind energy, this study evaluated the life cycle assessment for some new designs of submarine power cables developed by General Cable. To achieve this goal, three approaches have been carried out: leaching tests, eco-toxicity tests and Life Cycle Assessment (LCA) methodologies. All of them are aimed to obtaining quantitative data for environmental assessment of selected submarine cables. LCA is a method used to assess environmental aspects and potential impacts of a product or activity. LCA does not include financial and social factors, which means that the results of an LCA cannot exclusively form the basis for assessment of a product's sustainability. Leaching tests results allowed to conclude that pH of seawater did not significantly changed by the presence of submarine three-core cables. Although, it was slightly higher in case of broken cable, pH values were nearly equals. Concerning to the heavy metals which could migrate to the aquatic medium, there were significant differences in both scenarios. The leaching of zinc is the major environmental concern during undersea operation of undamaged cables whereas the fully sectioned three-core cable produced the migration of significant quantities of copper and iron apart from the zinc migrated from the galvanized steel. Thus, the tar

  3. What threat do turbidity currents and submarine landslides pose to submarine telecommunications cable infrastructure?

    Science.gov (United States)

    Clare, Michael; Pope, Edward; Talling, Peter; Hunt, James; Carter, Lionel

    2016-04-01

    The global economy relies on uninterrupted usage of a network of telecommunication cables on the seafloor. These submarine cables carry ~99% of all trans-oceanic digital data and voice communications traffic worldwide, as they have far greater bandwidth than satellites. Over 9 million SWIFT banks transfers alone were made using these cables in 2004, totalling 7.4 trillion of transactions per day between 208 countries, which grew to 15 million SWIFT bank transactions last year. We outline the challenge of why, how often, and where seafloor cables are broken by natural causes; primarily subsea landslides and sediment flows (turbidity currents and also debris flows and hyperpycnal flows). These slides and flows can be very destructive. As an example, a sediment flow in 1929 travelled up to 19 m/s and broke 11 cables in the NE Atlantic, running out for ~800 km to the abyssal ocean. The 2006 Pingtung earthquake triggered a sediment flow that broke 22 cables offshore Taiwan over a distance of 450 km. Here, we present initial results from the first statistical analysis of a global database of cable breaks and causes. We first investigate the controls on frequency of submarine cable breaks in different environmental and geological settings worldwide. We assess which types of earthquake pose a significant threat to submarine cable networks. Meteorological events, such as hurricanes and typhoons, pose a significant threat to submarine cable networks, so we also discuss the potential impacts of future climate change on the frequency of such hazards. We then go on to ask what are the physical impacts of submarine sediment flows on submerged cables? A striking observation from past cable breaks is sometimes cables remain unbroken, whilst adjacent cables are severed (and record powerful flows travelling at up to 6 m/s). Why are some cables broken, but neighbouring cables remain intact? We provide some explanations for this question, and outline the need for future in

  4. Novel Crosstalk Measurement Method for Multi-Core Fiber Fan-In/Fan-Out Devices

    DEFF Research Database (Denmark)

    Ye, Feihong; Ono, Hirotaka; Abe, Yoshiteru

    2016-01-01

    We propose a new crosstalk measurement method for multi-core fiber fan-in/fan-out devices utilizing the Fresnel reflection. Compared with the traditional method using core-to-core coupling between a multi-core fiber and a single-mode fiber, the proposed method has the advantages of high reliability...... and much shorter measurement time. Statistical properties of the measured crosstalk by the new method are found to be very similar to the ones by the traditional coupling method....

  5. Drivers for the development of an alluvial fan in a high-altitude glaciated catchment

    Science.gov (United States)

    Steiner, Jakob; Miles, Evan; Ragettli, Silvan

    2016-04-01

    Alluvial fans have channelization and deposition dynamics that are not entirely understood but can have considerable impact on the local hydrological regime. Especially in high-altitude and glaciated catchments they are rather rarely investigated. During glaciological field work between 2012 and 2015 in the Langtang catchment in the Nepalese Himalaya, such an alluvial fan of ca. 0.35 km2 (4000 m a.s.l.) at the end of a very small glaciated subcatchment (~9km2) was observed. The subcatchment is the site of one of the presumed largest landslides in earth's history, that likely happened 40 000 years ago with a volume of approximately 10^10 m3 and land surface erosion is well visible. During the recent Gorkha earthquake in April 2015 (M=7.8), additional sediments were mobilized along the steep valley slopes. From 6 sets of concurrent high-resolution satellite images and DEMs between 2006 and 2015 and an additional image from 1974 we derive the evolution in space and volume of this fan and identify main sources of sediment supply. Precipitation data from a nearby Automatic Weather Station provides insight into strong rainfall events. We can compare the growth of the fan in the period without significant earthquakes until April 2014 to the change after the seismic event (image from May 2015) and after the following Monsoon season (image from October 2015) and determine dominant drivers of erosion.

  6. Psychoacoustic study on contribution of fan noise to engine noise

    Science.gov (United States)

    Zhang, Junhong; Liu, Hai; Bi, Fengrong; Ni, Guangjian; Zhang, Guichang; Lin, Jiewei; Yu, Hanzhengnan

    2012-07-01

    There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure, and a lot of research achievements have been obtained. However, researches on the effect of fan noise to engine noise quality are lacking. The influences of the effects of fan structure optimization on the engine noise quality are unclear. Thus, there will be a decline in fan noise level, but the deterioration of engine noise quality. Aiming at the above problems, in consideration of fan structure design and engine noise quality, an innovative method to analyze the contribution of fan noise to engine noise quality using psychoacoustic theory is proposed. The noises of diesel engine installing different cooling fans are measured by using the acoustic pressure method. The experiment results are regarded as analysis samples. The model of sensory pleasantness is used to analyze the sound quality of a diesel engine with different cooling fans. Results show that after installing 10-blade fan in medium diameter the sensory pleasantness at each test point is increased, and the increase is 13.53% on average, which indicate the improvement of the engine noise quality. In order to verify the psychoacoustical analysis, the subjective assessment is carried out. The test result shows the noise quality of engine installed 10-blade fan in medium diameter is most superior. 1/3 octave frequency spectrum analysis is used to study the reason of the improvement of engine noise quality. It is found that after installing proper cooling fan the sound pressure level below 400 Hz are obviously increased, the frequency assignment and spectral envelope are more reasonable and a proper cooling fan can optimize the spectrum structure of the engine noise. The psychoacoustic study is applied in the contribution of fan noise to engine noise, and the idea of engine sound quality improvement through the structure optimization is proposed.

  7. Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress

    Science.gov (United States)

    2015-12-17

    propulsion technology first occurred many years ago: To help jumpstart the UK’s nuclear - powered submarine program, the United States transferred to the UK a... nuclear - powered attack submarines (SSNs), nuclear - powered cruise missile submarines (SSGNs), and nuclear - powered ballistic missile submarines (SSBNs). 2...2 In the designations SSN, SSGN, SSBN, and SSBN(X), the SS stands for submarine, N stands for nuclear - powered (meaning the ship is

  8. Constraints on Martian Fluvial Activity from Embedded-Crater Density in Alluvial Fans

    Science.gov (United States)

    Sneed, J.; Kite, E.; Mayer, D. P.

    2016-12-01

    Mars is one of only three bodies in the solar system known to have experienced surface reworking by fluvial action. This activity has been recorded in alluvial fan deposits as recently as the late Hesperian and early Amazonian, 3.0 Ga [1]. However, erosional products may be produced either by episodic wet periods or by a single (brief or sustained) climate regime. The intermittency of Mars' liquid water history is poorly constrained, with major implications for the planet's habitability and climate evolution. Here, we estimate the accumulation rate of crater-hosted alluvial fans, following the method of [2]. Embedded craters are local impact sites interbedded with fluvial deposits, recording the mutual interaction of water flow with crater morphology. Density of embedded craters is inversely proportional to the rate of sedimentary deposition; a single, brief wet period of rapid accumulation would be expected to produce only a small number of such craters. Conversely, episodic wet periods or a single long-lived wet climate would produce embedded craters at a relatively high density. We manually investigate the library of alluvial fan sites provided by [3]. Using 6m-per-pixel resolution enabled by the MRO's CTX camera, we obtain a comprehensive inventory of embedded craters in these features. Boundaries of each alluvial fan are determined by visual inspection, permitting an overall density estimate of embedded craters. We present the results of this analysis and discuss implications for models of the ancient Martian climate. [1] Grant & Wilson, 2011, Geophysical Research Letters, vol. 38 [2] Kite et. al., 2013, Icarus, vol. 225 [3] Wilson et. al., 2013, 44th Lunar and Planetary Science Conference

  9. Submarine landside in the Bussol Graben: Structural and formation features

    Science.gov (United States)

    Baranov, B. V.; Lobkovsky, L. I.; Dozorova, K. A.; Rukavishnikova, D. D.

    2017-05-01

    Analysis of geophysical data obtained during a study of the insular slope in the central Kuril‒Kamchatka Trench during projects Kuriles-2005 and Kuriles-2006 promoted by the Presidium of the Russian Academy of Sciences revealed a large submarine landslide in this area. The landslide, located at the bottom of the transverse valley confined to the Bussol l Graben, resulted from the failure of the northeastern wall of a graben composed of sedimentary material. It exceeds 35 km3 in size, representing one of the large submarine landslides discovered to date on the slope of the Kuril‒Kamchatka Trench in submarine canyonfan environments.

  10. Management of demand based inventory aboard submarine tenders servicing attack (SSN) submarines

    OpenAIRE

    Ross, Timothy Joseph

    1990-01-01

    Approved for public release; distribution is unlimited. This thesis examines the computation of inventory levels based on demand history aboard Submarine Tenders that use the Shipboard Automated Data Processing System (SUADPS) for inventory control. The focus of the thesis was the workload and supply effectiveness issues associated with the processing of the SUADPS levels setting program. The objective of the thesis was to determine the effect on supply effectiveness and stock churn if the...

  11. Numerical Study of Aeroacoustic Sound on Performance of Bladeless Fan

    Science.gov (United States)

    Jafari, Mohammad; Sojoudi, Atta; Hafezisefat, Parinaz

    2017-03-01

    Aeroacoustic performance of fans is essential due to their widespread application. Therefore, the original aim of this paper is to evaluate the generated noise owing to different geometric parameters. In current study, effect of five geometric parameters was investigated on well performance of a Bladeless fan. Airflow through this fan was analyzed simulating a Bladeless fan within a 2 m×2 m×4 m room. Analysis of the flow field inside the fan and evaluating its performance were obtained by solving conservations of mass and momentum equations for aerodynamic investigations and FW-H noise equations for aeroacoustic analysis. In order to design Bladeless fan Eppler 473 airfoil profile was used as the cross section of this fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter and aspect ratio for circular and quadratic cross sections were considered. Validating acoustic code results, we compared numerical solution of FW-H noise equations for NACA0012 with experimental results. FW-H model was selected to predict the noise generated by the Bladeless fan as the numerical results indicated a good agreement with experimental ones for NACA0012. To validate 3-D numerical results, the experimental results of a round jet showed good agreement with those simulation data. In order to indicate the effect of each mentioned parameter on the fan performance, SPL and OASPL diagrams were illustrated.

  12. Submarine thermal springs on the Galapagos Rift

    Science.gov (United States)

    Corliss, J.B.; Dymond, J.; Gordon, L.I.; Edmond, J.M.; Von Herzen, R. P.; Ballard, Richard D.; Green, K.; Williams, D.; Bainbridge, A.; Crane, K.; Van Andel, T. H.

    1979-01-01

    The submarine hydrothermal activity on and near the Galápagos Rift has been explored with the aid of the deep submersible Alvin. Analyses of water samples from hydrothermal vents reveal that hydrothermal activity provides significant or dominant sources and sinks for several components of seawater; studies of conductive and convective heat transfer suggest that two-thirds of the heat lost from new oceanic lithosphere at the Galápagos Rift in the first million years may be vented from thermal springs, predominantly along the axial ridge within the rift valley. The vent areas are populated by animal communities. They appear to utilize chemosynthesis by sulfur-oxidizing bacteria to derive their entire energy supply from reactions between the seawater and the rocks at high temperatures, rather than photosynthesis

  13. Improved OTEC System for a Submarine Robot

    Science.gov (United States)

    Chao, Yi; Jones, Jack; Valdez, Thomas

    2010-01-01

    An ocean thermal energy conversion (OTEC), now undergoing development, is a less-massive, more-efficient means of exploiting the same basic principle as that of the proposed system described in "Alternative OTEC Scheme for a Submarine Robot" (NPO-43500), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 50. The proposed system as described previously would be based on the thawing-expansion/freezing-contraction behavior of a wax or perhaps another suitable phase-change material (PCM). The power generated by the system would be used to recharge the batteries in a battery- powered unmanned underwater vehicle [UUV (essentially, a small exploratory submarine robot)] of a type that has been deployed in large numbers in research pertaining to global warming. A UUV of this type travels between the ocean surface and depths, measuring temperature and salinity. At one phase of its operational cycle, the previously proposed system would utilize the surface ocean temperature (which lies between 15 and 30 C over most of the Earth) to melt a PCM that has a melting/freezing temperature of about 10 C. At the opposite phase of its operational cycle, the system would utilize the lower ocean temperature at depth (e.g., between 4 and 7 C at a depth of 300 m) to freeze the PCM. The melting or freezing would cause the PCM to expand or contract, respectively, by about 9 volume percent. The PCM would be contained in tubes that would be capable of expanding and contracting with the PCM. The PCM-containing tubes would be immersed in a hydraulic fluid. The expansion and contraction would drive a flow of the hydraulic fluid against a piston that, in turn, would push a rack-and-pinion gear system to spin a generator to charge a battery.

  14. A numerical analysis of flat fan aerial crop spray

    Science.gov (United States)

    Malik Fesal, Siti Natasha; Fawzi, Mas; Omar, Zamri

    2017-09-01

    Spray drift mitigation, in the agriculture aerial spraying literature, and spray quality in the application of plant protection products, still continues as two critical components in evaluating shareholder value. A study on off-target drift and ground deposit onto a 250 m strip were simulated through series of Computational Fluid Dynamic (CFD) simulations. The drift patterns for evaporating droplets were released from a constant aircraft velocity at 30 m/s (60 mph) carrying 20 m swath width spray boom with 12 fan-type nozzles at released height from the ground ranging from 3.7 m to 4.7 m. Droplet trajectories are calculated from the given airspeed with a Lagrangian model for particle dispersion excluding any wind effect perturbation. The proposed CFD’s model predictions agreed well with cited literatures for a wide range of atmospheric stability values. The results revealed that there is considerable increased in spray drift and droplets trajectories with the increased in spray released height. It suggested that a combination of low aircraft spray released height with low airspeed is essential to improve spray quality and maximizing uniform deposition on the target area are significant in minimizing spray drift risks.

  15. Debris flow recurrence periods and multi-temporal observations of colluvial fan evolution in central Spitsbergen (Svalbard)

    Science.gov (United States)

    Bernhardt, H.; Reiss, D.; Hiesinger, H.; Hauber, E.; Johnsson, A.

    2017-11-01

    Fan-shaped accumulations of debris flow deposits are common landforms in polar regions such as Svalbard. Although depositional processes in these environments are of high interest to climate as well as Mars-analog research, several parameters, e.g., debris flow recurrence periods, remain poorly constrained. Here, we present an investigation based on remote sensing as well as in situ data of a 0.4 km2 large colluvial fan in Hanaskogdalen, central Spitsbergen. We analyzed high resolution satellite and aerial images covering five decades from 1961 to 2014 and correlated them with lichenometric dating as well as meteorological data. Image analyses and lichenometry deliver consistent results and show that the recurrence period of large debris flows (≥ 400 m3) is about 5 to 10 years, with smaller flows averaging at two per year in the period from 2008 to 2013. While this is up to two orders of magnitude shorter than previous estimates for Svalbard (80 to 500 years), we found the average volume of 220 m3 per individual flow to be similar to previous estimates for the region. Image data also reveal that an avulsion took place between 1961 and 1976, when the active part of the fan moved from its eastern to its western portion. A case study of the effects of a light rain event ( 5 mm/day) in the rainy summer of 2013, which triggered a large debris flow, further shows that even light precipitation can trigger major flows. This is made possible by multiple light rain events or gradual snow melt pre-saturating the permafrost ground and has to be taken into account when predicting the likelihood of potentially hazardous mass wasting in polar regions. Furthermore, our findings imply a current net deposition rate on the colluvial fan of 480 m3/year, which is slightly less than the integrated net deposition rate of 576 to 720 m3/year resulting from the current fan volume divided by the 12,500 to 10,000 years since the onset of fan build-up after the area's deglaciation. However

  16. Submarine landslide triggered by eruption recorded by in-situ hydrophone at NW Rota-1 submarine volcano, Mariana Arc (Invited)

    Science.gov (United States)

    Chadwick, B.; Dziak, R. P.; Embley, R. W.; Tunnicliffe, V.; Sherrin, J.; Cashman, K. V.; Deardorff, N.

    2010-12-01

    An expedition to NW Rota-1, Mariana Arc, in March 2010 with R/V Kilo Moana and ROV Jason found that the submarine volcano (summit depth 520 m) was still erupting more or less continuously as has been observed since 2004, In addition, the expedition also discovered that a major landslide had occurred since the last visit in April 2009, demonstrating the dynamic processes of eruption, collapse, and regrowth in the submarine arc environment. The dive observations reveal the responses of the volcano’s magmatic and hydrothermal systems to such a collapse, as well as how the resident chemosynthetic biological community has responded to the event. The morphologic changes from the landslide can be quantified by comparing multibeam bathymetric surveys between 2009 and 2010. The headwall of the slide is now ~100 m north of the former summit ridge where depth changes up to -90 m occurred between surveys. The slide excavated material from the upper southern slope of the volcano to a distance of 3.5 km downslope, and deposited material between 2-8 km from the summit down to at least 2800 m on the volcano flank. The area and volume of slide deposits (positive depth changes) are 7.1 x 106 m2 and 5.3 x 107 m3, respectively, and the maximum thickness is +42 m. The area and volume of material removed by the slide (negative depth changes) are 2.2 x 106 m2 and -4.1 x 107 m3, respectively. We have found no evidence for a local tsunami generated by this event. The changes in morphology near the summit show that the landslide primarily removed loose volcaniclastic deposits that had accumulated near the active eruptive vent, exposing an underlying stock-like core of resistant intrusive rocks and massive lavas at the summit. During March 2010, there were at least 5 active eruptive vents, located along a line 200-m long, that changed between active and inactive day-to-day and even hour-to-hour, suggesting that the near-surface magmatic plumbing system was still reorganizing after the

  17. 'Bataille's boys': postmodernity, Fascists and football fans.

    Science.gov (United States)

    Smith, T

    2000-09-01

    In his analysis of football hooliganism, Anthony King claims to reveal the historical, conceptual scheme young, male supporters draw upon. This 'masculine vision', he states, is similar to that held by the Freikorps. Both groups are said to adhere to modernist notions of masculinity, sexuality and nationhood, reinforced by rituals which maintain boundaries between these 'proper' males and deviant 'others'. Occasionally, football hooligans breach these boundaries in acts of postmodern transgression. King also claims that fans link sex and violence in their imaginations. In this response I examine King's critique of his fellow theorists; challenge his 'Freikorps-Fans' analogy; demonstrate the problem he has in establishing the sex-violence link and question the relevance of his concept of postmodernity.

  18. Performance Study of a Ducted Fan System

    Science.gov (United States)

    Abrego, Anita I.; Bulaga, Robert W.; Rutkowski, Michael (Technical Monitor)

    2002-01-01

    An experimental investigation was completed in the NASA Ames 7- by 10-Foot Wind Tunnel with the objective of determining the performance characteristics of a ducted fan. The model was an annular duct with a 38-in diameter, 10-in chord, and a 5-bladed fixed-pitch fan. Model variations included duct angle of attack, exit vane flap length, flap deflection angle, and duct chord length. Duct performance data were obtained for axial and forward flight test conditions. Axial flow test data showed figure of merit decreases with increasing advance ratio. Forward flight data showed an increasing propulsive force with decreasing duct angle of attack. Exit vane flap deflection angle and flap chord length were shown to be an effective way of providing side force. Extending the duct chord did not effect the duct performance.

  19. A model for tidewater glacier undercutting by submarine melting

    Science.gov (United States)

    Slater, D. A.; Nienow, P. W.; Goldberg, D. N.; Cowton, T. R.; Sole, A. J.

    2017-03-01

    Dynamic change at the marine-terminating margins of the Greenland Ice Sheet may be initiated by the ocean, particularly where subglacial runoff drives vigorous ice-marginal plumes and rapid submarine melting. Here we model submarine melt-driven undercutting of tidewater glacier termini, simulating a process which is key to understanding ice-ocean coupling. Where runoff emerges from broad subglacial channels we find that undercutting has only a weak impact on local submarine melt rate but increases total ablation by submarine melting due to the larger submerged ice surface area. Thus, the impact of melting is determined not only by the melt rate magnitude but also by the slope of the ice-ocean interface. We suggest that the most severe undercutting occurs at the maximum height in the fjord reached by the plume, likely promoting calving of ice above. It remains unclear, however, whether undercutting proceeds sufficiently rapidly to influence calving at Greenland's fastest-flowing glaciers.

  20. Submarine Upward Looking Sonar Ice Draft Profile Data and Statistics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of upward looking sonar draft data collected by submarines in the Arctic Ocean. It includes data from both U.S. Navy and Royal Navy...

  1. Virtual Reality Training System for a Submarine Command Center

    National Research Council Canada - National Science Library

    Maxwell, Douglas B

    2008-01-01

    The invention as disclosed is a system that uses a combined real and virtual display interaction methodology to generate the visual appearance of submarine combat control rooms and allow interaction...

  2. Mementoes: Raul Seixas’ fans and their collections

    Directory of Open Access Journals (Sweden)

    Juliana Abonizio

    2015-05-01

    Full Text Available Raul Seixas’ fans are collectors of several objects. In order to unveil the relationship of the collectors with the idol, with others, and with themselves, I reviewed the letters sent to Raul Rock Club and analyzed his collection. The articulations among the various forms of relating with objects of the singer, or that refer to him, show that the collectible objects, more than vehicles of social reproduction, can function as poetic devices.

  3. Gigapixel Images Connect Sports Teams with Fans

    Science.gov (United States)

    2013-01-01

    Technology developed at Ames Research Center to take high-resolution imagery on Mars is now being used in baseball stadiums across the country. New York City-based Major League Baseball Advanced Media LP customized the platform to accommodate in-game shots that capture nearly the whole stadium. Fans navigate the photos online and tag themselves and their friends using social media tools.

  4. Depositional environments of the south-eastern Volga-Ural anteclise in the Early-Middle Devonian.

    Science.gov (United States)

    Selezeneva, Natalia

    2017-04-01

    Nowadays, in the Orenburg region of Russia hydrocarbon potential has been determined down to a depth of 5 km. Therefore, discovery of deep fields is becoming a pressing issue there. Seismic profiles on the south-eastern part of Volga-Ural anteclise indicate two uplifts at the depth of 6-7 km composed of Emsian-Givetian deposits which likely represent large carbonate buildups. Then facies analysis of this territory (based on data of about 100 boreholes) was made and it confirmed the presence of bioherm massifs and showed sedimentary environments. Analysis of the composition and the structure of deposits revealed that in the Emsian stage a shallow-water shelf basin existed, which deepened toward the Ural and North Caspian basins and was characterized by the transgressive evolution. The early stage of transgression was dominated by the terrigenous sedimentation. This region likely had a prodelta with three (proximal, intermediate, and distal) zones. Then the basin was deepened, the amount of terrigenous material decreased and carbonate massifs started to form. At that time following environments occurred: shallow-water coastal zone, intrabasin uplift, shallow-water distal zone, relatively deep-water zone and riftogenic carbonate buildups. Facies analysis of Eifelian sediments showed that there were two shallow-water zones, where carbonates were deposed with formation of small separate organic structures, surrounded by relatively deep-water zone. Continued submergence caused development of bioherm massifs. Givetian deposits differed from the Eifelian by abundant input of the terrigenous material. The growth of the bioherm massifs stopped during this time. Due to facies analyses such paleogeographic zones as shallow-water coastal zone, deep-water shelf zone, submarine fan zone were defined. As a result, two buried reefs were discovered, which could be perspective for finding out oil and gas. These bioherms are covered by the Tournaisian depression sediments that could

  5. Harmonic Balance Computations of Fan Aeroelastic Stability

    Science.gov (United States)

    Bakhle, Milind A.; Reddy, T. S. R.

    2010-01-01

    A harmonic balance (HB) aeroelastic analysis, which has been recently developed, was used to determine the aeroelastic stability (flutter) characteristics of an experimental fan. To assess the numerical accuracy of this HB aeroelastic analysis, a time-domain aeroelastic analysis was also used to determine the aeroelastic stability characteristics of the same fan. Both of these three-dimensional analysis codes model the unsteady flowfield due to blade vibrations using the Reynolds-averaged Navier-Stokes (RANS) equations. In the HB analysis, the unsteady flow equations are converted to a HB form and solved using a pseudo-time marching method. In the time-domain analysis, the unsteady flow equations are solved using an implicit time-marching approach. Steady and unsteady computations for two vibration modes were carried out at two rotational speeds: 100 percent (design) and 70 percent (part-speed). The steady and unsteady results obtained from the two analysis methods compare well, thus verifying the recently developed HB aeroelastic analysis. Based on the results, the experimental fan was found to have no aeroelastic instability (flutter) at the conditions examined in this study.

  6. Studies on submarine control for periscope depth operations

    OpenAIRE

    Tolliver, John V.

    1996-01-01

    Approved for public release; distribution in unlimited. Requirements for submarine periscope depth operations have been increased by integration with carrier battle groups, littoral operations, and contributions to joint surveillance. Improved periscope depth performance is therefore imperative. Submarine control personnel rely on a large number of analog gauges and indications. An integrated digital display system could enhance the ergonomics of the human control interface and display add...

  7. Exercise Aboard Attack Submarines: Rationale and New Options

    Science.gov (United States)

    2004-08-18

    experience loss of physical fitness while underway. Bennett and co-workers (2) noted a 7% reduction of maximal oxygen consumption in non-exercising...Inc. designed and built a comprehensive resistance exercise device to help counteract muscle deconditioning during long term space flights (the SX... Physical activity aboard nuclear submarines as measured by pedometry. Groton: Naval Submarine Medical Research Laboratory, Report 1053, 1985, p. 12

  8. Are tilt measurements useful in detecting tsunamigenic submarine landslides?

    OpenAIRE

    Sascha Brune; Andrey Babeyko; Stephan V. Sobolev

    2009-01-01

    Large submarine landslides can generate dangerous tsunamis. Because of their long-period signal, detection of landslides by common seismological methods is difficult. Here we suggest a method of detecting submarine landslides by using an array of land-based tiltmeters. The displacement of a large volume of sediments during landsliding produces a detectable elastic response of the lithosphere. We propose a technique to calculate this response and to invert for tsunami relevant parameters like ...

  9. FUTURE STUDIES AT PENA BLANCA: RADIONUCLIDE MIGRATION IN THE VADOSE ZONE OF AN ALLUVIAL FAN

    Energy Technology Data Exchange (ETDEWEB)

    P. Goodell; J. Walton; P.J. Rodriguez

    2005-07-11

    The pathway to the accessible environment at Yucca Mountain contains volcanic rocks and alluvial fill. Transport properties in alluvial fill, specifically retardation and dispersivity, may be significant in determining the overall performance of the repository. Prior relevant studies, with the exception of the Nye County Tracer Test, are almost entirely in bedrock material. The proposed study will provide field data on radionuclide migration in alluvial material. High grade uranium ore was mined at the Nopal I deposit. This mined ore (60,000 tons) was moved in 1994 to its present site as open piles on an alluvial fan in the Boquilla Colorada Microbasin. Precipitation is approximately 20 cm/year, and has caused migration of radionuclides into the subsurface. We propose partial removal of an ore pile, excavation into the alluvial fan, sampling, and determination of radionuclide mobilities from the uranium decay chain. The proposed research would be taking advantage of a unique opportunity with a known time frame for migration.

  10. The development of permafrost bacterial communities under submarine conditions

    Science.gov (United States)

    Mitzscherling, Julia; Winkel, Matthias; Winterfeld, Maria; Horn, Fabian; Yang, Sizhong; Grigoriev, Mikhail N.; Wagner, Dirk; Overduin, Pier P.; Liebner, Susanne

    2017-07-01

    Submarine permafrost is more vulnerable to thawing than permafrost on land. Besides increased heat transfer from the ocean water, the penetration of salt lowers the freezing temperature and accelerates permafrost degradation. Microbial communities in thawing permafrost are expected to be stimulated by warming, but how they develop under submarine conditions is completely unknown. We used the unique records of two submarine permafrost cores from the Laptev Sea on the East Siberian Arctic Shelf, inundated about 540 and 2500 years ago, to trace how bacterial communities develop depending on duration of the marine influence and pore water chemistry. Combined with geochemical analysis, we quantified total cell numbers and bacterial gene copies and determined the community structure of bacteria using deep sequencing of the bacterial 16S rRNA gene. We show that submarine permafrost is an extreme habitat for microbial life deep below the seafloor with changing thermal and chemical conditions. Pore water chemistry revealed different pore water units reflecting the degree of marine influence and stages of permafrost thaw. Millennia after inundation by seawater, bacteria stratify into communities in permafrost, marine-affected permafrost, and seabed sediments. In contrast to pore water chemistry, the development of bacterial community structure, diversity, and abundance in submarine permafrost appears site specific, showing that both sedimentation and permafrost thaw histories strongly affect bacteria. Finally, highest microbial abundance was observed in the ice-bonded seawater unaffected but warmed permafrost of the longer inundated core, suggesting that permafrost bacterial communities exposed to submarine conditions start to proliferate millennia after warming.

  11. Cardiometabolic Health in Submariners Returning from a 3-Month Patrol

    Directory of Open Access Journals (Sweden)

    Heath G. Gasier

    2016-02-01

    Full Text Available Confined space, limited exercise equipment, rotating shift work and reduced sleep may affect cardiometabolic health in submariners. To test this hypothesis, 53 male U.S. Submariners (20–39 years were studied before and after a 3-month routine submarine patrol. Measures included anthropometrics, dietary and physical activity, biomarkers of cardiometabolic health, energy and appetite regulation, and inflammation. Before deployment, 62% of submariners had a body fat % (BF% ≥ 25% (obesity, and of this group, 30% met the criteria for metabolic syndrome. In obese volunteers, insulin, the homeostatic model assessment of insulin resistance (HOMA-IR, leptin, the leptin/adiponectin ratio, and pro-inflammatory chemokines growth-related oncogene and macrophage-derived chemokine were significantly higher compared to non-obese submariners. Following the patrol, a significant mean reduction in body mass (5% and fat-mass (11% occurred in the obese group as a result of reduced energy intake (~2000 kJ during the patrol; and, independent of group, modest improvements in serum lipids and a mean reduction in interferon γ-induced protein 10 and monocyte chemotactic protein 1 were observed. Since 43% of the submariners remained obese, and 18% continued to meet the criteria for metabolic syndrome following the patrol, the magnitude of weight loss was insufficient to completely abolish metabolic dysfunction. Submergence up to 3-months, however, does not appear to be the cause of obesity, which is similar to that of the general population.

  12. Solution of Supplee's submarine paradox through special and general relativity

    CERN Document Server

    Vieira, R S

    2016-01-01

    In 1989 Supplee described an apparent relativistic paradox on which a submarine seems to sink in a given frame while floating in another one. If the submarine density is adjusted to be the same as the water density (when both of them are at rest) and then it is put to move, the density of the submarine will become higher than that of the water, thanks to Lorentz contraction, and hence it sinks. However, in the submarine proper frame, is the water that becomes denser, so the submarine supposedly should float and we get a paradox situation. In this paper we analyze the submarine paradox in both a flat and a curved spacetime. In the case of a flat spacetime, we first show that any relativistic force field in special relativity can be written in the Lorentz form, so that it can always be decomposed into a static (electric-like) and a dynamic (magnetic-like) part. Taking into account the gravitomagnetic effects between the Earth and the water, a relativistic formulation of Archimedes principle can be established, ...

  13. Fan edits and the legacy of The Phantom Edit

    Directory of Open Access Journals (Sweden)

    Joshua Wille

    2014-09-01

    Full Text Available A fan edit can generally be defined as an alternative version of a film or television text created by a fan. It offers a different viewing experience, much as a song remix offers a different listening experience. The contemporary wave of fan edits has emerged during the remix zeitgeist of digital media and at a time when digital video editing technology has become more affordable and popular. The increasing number of alternative versions of films and the works of revisionist Hollywood filmmakers such as George Lucas have contributed to a greater public understanding of cinema as a fluid medium instead of one that exists in a fixed form. The Phantom Edit (2000, a seminal fan edit based on Lucas's Star Wars Episode I: The Phantom Menace (1999, inspired new ranks of fan editors. However, critics have misunderstood fan edits as merely the work of disgruntled fans. In order to provide a critical and historical basis for studies in fan editing as a creative practice, I examine previous interpretations of fan edits in the context of relevant contemporary works, and I use an annotated chronology of The Phantom Edit to trace its influence on subsequent fan editing communities and uncover their relationship with intellectual property disputes.

  14. "Emotions-Only" versus "Special People": Genre in fan discourse

    Directory of Open Access Journals (Sweden)

    Louisa Ellen Stein

    2008-09-01

    Full Text Available This essay looks at genre as a complex set of discursive threads running unevenly through production, TV text, and fan reception. Through a case study of the reception of fan favorite Roswell, this essay interrogates the role of genre in spectatorship. In its mixing of teen and science fiction elements, Roswell trod upon contested generic spaces, eliciting strong reaction from its viewers. Connections between genre and gender came to the fore, as producer commentary linked science fiction with male audiences and teen romance with female audiences. Fans responded with analyses that greatly complicated and at times overtly rejected industrial suppositions regarding the gendered work of genre. Through these fan conversations, we can witness the complexity of genre as discursive thread moving through not only TV texts but also multivariant fan responses. I intend this essay to work at two levels. My analysis of fan responses to Roswell models the possibilities of a close study of genre discourse. At the same time, my case study probes the nature of genre in fan engagement, as genre discourses intersect with other fan concerns such as character identification, perceptions of textual quality, and questions of gender representation. While we cannot necessarily look to fan accounts for proof of how viewers engage with genre, they do tell us how fans frame their engagement with genre, how they incorporate genre into their performance of fannishness, and how they perform and thus enact genre itself as a shared cultural process.

  15. Advanced Low-Noise Research Fan Stage Design

    Science.gov (United States)

    Neubert, Robert; Bock, Larry; Malmborg, Eric; Owen-Peer, William

    1997-01-01

    This report describes the design of the Advanced Low-Noise Research Fan stage. The fan is a variable pitch design, which is designed at the cruise pitch condition. Relative to the cruise setting, the blade is closed at takeoff and opened for reverse thrust operation. The fan stage is a split flow design with fan exit guide vanes (FEGVs) and core stators. The fan stage design is combined with a nacelle and engine core duct to form a powered fan/nacelle subscale model. This model is intended for use in combined aerodynamic, acoustic, and structural testing in a wind tunnel. The fan has an outer diameter of 22 in. and a hub-to-tip of 0.426 in., which allows the use of existing NASA fan and cowl force balance and rig drive systems. The design parameters were selected to permit valid acoustic and aerodynamic comparisons with the Pratt & Whitney (P&W) 17- and 22-in. rigs previously tested under NASA contract. The fan stage design is described in detail. The results of the design axisymmetric and Navier-Stokes aerodynamic analysis are presented at the critical design conditions. The structural analysis of the fan rotor and attachment is included. The blade and attachment are predicted to have adequate low-cycle fatigue life and an acceptable operating range without resonant stress or flutter. The stage was acoustically designed with airfoil counts in the FEGV and core stator to minimize noise. A fan/FEGV tone analysis developed separately under NASA contract was used to determine the optimum airfoil counts. The fan stage was matched to the existing nacelle, designed under the previous P&W low-noise contract, to form a fan/nacelle model for wind tunnel testing. It is an axisymmetric nacelle for convenience in testing and analysis. Previous testing confirmed that the nacelle performed as required at various aircraft operating conditions.

  16. Electrical Resistivity Tomography and Induced Polarization for Mapping the Subsurface of Alluvial Fans: A Case Study in Punata (Bolivia

    Directory of Open Access Journals (Sweden)

    Andres Gonzales Amaya

    2016-11-01

    Full Text Available Conceptual models of aquifer systems can be refined and complemented with geophysical data, and they can assist in understanding hydrogeological properties such as groundwater storage capacity. This research attempts to use geoelectrical methods, Electrical Resistivity Tomography and Induced Polarization parameters, for mapping the subsurface in alluvial fans and to demonstrate its applicability; the Punata alluvial fan was used as a case study. The resistivity measurements proved to be a good tool for mapping the subsurface in the fan, especially when used in combination with Induced Polarization parameters (i.e., Normalized Chargeability. The Punata alluvial fan characterization indicated that the top part of the subsurface is composed of boulders in a matrix of finer particles and that the grain size decreases with depth; the electrical resistivity of these deposits ranged from 200 to 1000 Ωm, while the values of normalized chargeability were lower than 0.05 mS/m. The bottom of the aquifer system consisted of a layer with high clay content, and the resistivity ranged from 10 to 100 Ωm, while the normalized chargeability is higher than 0.07 mS/m. With the integration of these results and lithological information, a refined conceptual model is proposed; this model gives a more detailed description of the local aquifer system. It can be concluded that geoelectrical methods are useful for mapping aquifer systems in alluvial fans.

  17. Grain size trends reveal alluvial fan sensitivity to late Pleistocene climate change

    Science.gov (United States)

    Whittaker, A. C.; D'Arcy, M. K.; Roda Boluda, D. C.

    2015-12-01

    The effects of climate change on eroding landscapes and the sedimentary record remain poorly understood. The measurement of grain size fining rates in stream-flow dominated deposits provides one way to address this issue because, in principle, these trends embed important information about the dynamics of sediment routing systems and their sensitivities to external forcing. At a fundamental level, downstream fining is often driven by selective deposition of sediment. The relative efficiency of this process is determined by the physical characteristics of the input sediment supply and the spatial distribution of subsidence rate, which generates the accommodation necessary for mass extraction. Here, we measure grain size fining rates from apex to toe on two alluvial fan systems in northern Death Valley, California, which have well-exposed modern and 70 ka surfaces, where the long-term tectonic boundary conditions are known and where climatic variation over this time period is well-constrained. We integrate a self-similar gravel fraction fining model, based on selective sediment extraction, with cosmogenically-derived catchment erosion rates and gravel fining data, to estimate the change in sediment flux that occurred between 70 ka and the present day. Our results show that a 30 % decrease in average precipitation rate led to a 20 % decrease in sediment flux and a clear increase in the down-fan rate of fining. This supports existing landscape evolution models that relate a decrease in precipitation rate to a decrease in sediment flux, but implies that this relationship may be sub-linear. This study offers a new approach to applying grain size fining models to mountain catchments and their alluvial fan systems, and shows fan stratigraphy can be highly sensitive to climate changes over <105 years. However we also observe that this sensitivity is lost when sediment is remobilised and recycled over a time period longer than the duration of the climatic perturbation.

  18. Anatomy of La Jolla submarine canyon system; offshore southern California

    Science.gov (United States)

    Paull, C.K.; Caress, D.W.; Lundsten, E.; Gwiazda, R.; Anderson, K.; McGann, M.; Conrad, J.; Edwards, B.; Sumner, E.J.

    2013-01-01

    An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall geometry of the La Jolla Canyon especially with respect to the pre-canyon host sediments. The floor of the axial channel is covered with unconsolidated sand similar to the sand on the shelf near the canyon head, lacks outcrops of the pre-canyon host strata, has an almost constant slope of 1.0° and is covered with trains of crescent shaped bedforms. The presence of modern plant material entombed within these sands confirms that the axial channel is presently active. The sand on the canyon floor liquefied during vibracore collection and flowed downslope, illustrating that the sediment filling the channel can easily fail even on this gentle slope. Data from the canyon walls help constrain the age of the canyon and extent of incision. Horizontal beds of moderately cohesive fine-grained sediments exposed on the steep canyon walls are consistently less than 1.232 million years old. The lateral continuity of seismic reflectors in minisparker profiles indicate that pre-canyon host strata extend uninterrupted from outside the canyon underneath some terraces within the canyon. Evidence of abandoned channels and point bar-like deposits are noticeably absent on the inside bend of channel meanders and in the subsurface of the terraces. While vibracores from the surface of terraces contain thin (< 10 cm) turbidites, they are inferred to be part of a veneer of recent sediment covering pre-canyon host sediments that underpin the terraces. The combined use of state of the art seafloor mapping and exploration tools provides a uniquely detailed view of the morphology within an active submarine canyon.

  19. The Congolobe project, a multidisciplinary study of Congo deep-sea fan lobe complex: Overview of methods, strategies, observations and sampling

    Science.gov (United States)

    Rabouille, C.; Olu, K.; Baudin, F.; Khripounoff, A.; Dennielou, B.; Arnaud-Haond, S.; Babonneau, N.; Bayle, C.; Beckler, J.; Bessette, S.; Bombled, B.; Bourgeois, S.; Brandily, C.; Caprais, J. C.; Cathalot, C.; Charlier, K.; Corvaisier, R.; Croguennec, C.; Cruaud, P.; Decker, C.; Droz, L.; Gayet, N.; Godfroy, A.; Hourdez, S.; Le Bruchec, J.; Saout, J.; Le Saout, M.; Lesongeur, F.; Martinez, P.; Mejanelle, L.; Michalopoulos, P.; Mouchel, O.; Noel, P.; Pastor, L.; Picot, M.; Pignet, P.; Pozzato, L.; Pruski, A. M.; Rabiller, M.; Raimonet, M.; Ragueneau, O.; Reyss, J. L.; Rodier, P.; Ruesch, B.; Ruffine, L.; Savignac, F.; Senyarich, C.; Schnyder, J.; Sen, A.; Stetten, E.; Sun, Ming Yi; Taillefert, M.; Teixeira, S.; Tisnerat-Laborde, N.; Toffin, L.; Tourolle, J.; Toussaint, F.; Vétion, G.; Jouanneau, J. M.; Bez, M.; Congolobe group:

    2017-08-01

    The presently active region of the Congo deep-sea fan (around 330,000 km2), called the terminal lobes or lobe complex, covers an area of 2500 km2 at 4700-5100 m water depth and 750-800 km offshore. It is a unique sedimentary area in the world ocean fed by a submarine canyon and a channel-levee system which presently deliver large amounts of organic carbon originating from the Congo River by turbidity currents. This particularity is due to the deep incision of the shelf by the Congo canyon, up to 30 km into the estuary, which funnels the Congo River sediments into the deep-sea. The connection between the river and the canyon is unique for major world rivers. In 2011, two cruises (WACS leg 2 and Congolobe) were conducted to simultaneously investigate the geology, organic and inorganic geochemistry, and micro- and macro-biology of the terminal lobes of the Congo deep-sea fan. Using this multidisciplinary approach, the morpho-sedimentary features of the lobes were characterized along with the origin and reactivity of organic matter, the recycling and burial of biogenic compounds, the diversity and function of bacterial and archaeal communities within the sediment, and the biodiversity and functioning of the faunal assemblages on the seafloor. Six different sites were selected for this study: Four distributed along the active channel from the lobe complex entrance to the outer rim of the sediment deposition zone, and two positioned cross-axis and at increasing distance from the active channel, thus providing a gradient in turbidite particle delivery and sediment age. This paper aims to provide the general context of this multidisciplinary study. It describes the general features of the site and the overall sampling strategy and provides the initial habitat observations to guide the other in-depth investigations presented in this special issue. Detailed bathymetry of each sampling site using 0.1-1 m resolution multibeam obtained with a remotely operated vehicle (ROV

  20. Submarine Landslides at Santa Catalina Island, California

    Science.gov (United States)

    Legg, M. R.; Francis, R. D.

    2011-12-01

    Santa Catalina Island is an active tectonic block of volcanic and metamorphic rocks originally exposed during middle Miocene transtension along the evolving Pacific-North America transform plate boundary. Post-Miocene transpression created the existing large pop-up structure along the major strike-slip restraining bend of the Catalina fault that forms the southwest flank of the uplift. Prominent submerged marine terraces apparent in high-resolution bathymetric maps interrupt the steep submarine slopes in the upper ~400 meters subsea depths. Steep subaerial slopes of the island are covered by Quaternary landslides, especially at the sea cliffs and in the blueschist metamorphic rocks. The submarine slopes also show numerous landslides that range in area from a few hectares to more than three sq-km (300 hectares). Three or more landslides of recent origin exist between the nearshore and first submerged terrace along the north-facing shelf of the island's West End. One of these slides occurred during September 2005 when divers observed a remarkable change in the seafloor configuration after previous dives in the area. Near a sunken yacht at about 45-ft depth where the bottom had sloped gently into deeper water, a "sinkhole" had formed that dropped steeply to 100-ft or greater depths. Some bubbling sand was observed in the shallow water areas that may be related to the landslide process. High-resolution multibeam bathymetry acquired in 2008 by CSU Monterey Bay show this "fresh" slide and at least two other slides of varying age along the West End. The slides are each roughly 2 hectares in area and their debris aprons are spread across the first terrace at about 85-m water depth that is likely associated with the Last Glacial Maximum sealevel lowstand. Larger submarine slides exist along the steep Catalina and Catalina Ridge escarpments along the southwest flank of the island platform. A prominent slide block, exceeding 3 sq-km in area, appears to have slipped more than

  1. Chronostratigraphy and geomorphology of washover fans in the Exmouth Gulf (NW Australia) - A record of tropical cyclone activity during the late Holocene

    Science.gov (United States)

    May, Simon Matthias; Brill, Dominik; Leopold, Matthias; Callow, John Nikolaus; Engel, Max; Scheffers, Anja; Opitz, Stephan; Norpoth, Maike; Brückner, Helmut

    2017-08-01

    Washover fans typically form due to barrier overwash or breaching and coastal inundation and generally represent geomorphological and depositional evidence of intense storms. Few studies have investigated the chronostratigraphy of washover fans in order to infer magnitude/frequency patterns of extreme-wave events over longer time scales. Here we present new data on the chronostratigraphy of late Holocene washover fans in the Exmouth Gulf (Western Australia) by using ground penetrating radar and unmanned aerial vehicle (UAV) survey techniques, as well as geomorphological, sedimentological and chronological investigations. This study aims to (i) provide a detailed characterization of the washover fans' geomorphology and stratigraphical architecture; (ii) document depositional processes involved in their formation; (iii) establish a chronostratigraphy based on optically stimulated luminescence (OSL); and (iv) understand the significance of the washover fans for recording past tropical cyclone (TC) activity. The fans consist of multiple sequences of sand, shell debris and coral rubble comprising depositional units related to TC-induced inundation. The units are separated by palaeosurfaces with incipient soil formation, formed during periods of reduced depositional activity. In combination with the interpretation of a UAV-based high-resolution digital surface model, multiple phases of reactivation are inferred. OSL results allow the establishment of a local long-term TC record and suggest storm-induced deposition at ∼170, ∼360, ∼850 and ∼1300 years ago. Further units were dated to ∼1950, ∼2300, and ∼2850 years ago. The chronology of TC events is consistent with other work relating TC activity with El Niño Southern Oscillation (ENSO) and sea surface temperature (SST) patterns, corroborating the regional palaeotempestological relevance of this unique geomorphological record.

  2. Relationship between work stress and health in submariners

    Directory of Open Access Journals (Sweden)

    Nan-nan JIANG

    2013-09-01

    Full Text Available Objective To explore the relationship between work stress and health in submariners. Methods In April 2008, 272 submariners trained in a navy base were selected as study subjects by random group sampling method, and tested by primary personal information questionnaire, self-rated health measurement scale (SRHMS, self-developed submariners' work stressors questionnaire, and work stress self-rated scale. Physical health, mental health and social health of submariners were analyzed, and scores were compared with the norm of reference scores. Correlations were analyzed respectively between 10 items of submariners' general information (including age, length of military service, education degree, years at the present post, times of receiving awards, on-duty hours, off-duty hours, hours of sleep, lost days of leave, positive attitude to work and their physical health score, mental health score, social health score, total health score, as well as between 15 submariners' work stressors (including workrelated risks, diet problems, high temperature, humidity and noise in workplace, shortage of clean clothes, illness, losing contact with outside, lack of information about the task, lacking supports from family members, relationship problems, lack of involvement in task decisions, boring and dull work, on duty, heavy work, high quality of work, coping with unexpected threat and their physical health score, mental health score, social health score and total health score. Results No significant difference was found between submariners' SRHMS total score and the normal referenced score (t=0.56, P>0.05, but the physical health score and mental health score were significantly lower than normal referenced scores respectively (t=–2.172, P<0.05; t=–3.299, P<0.01, and the social health score was significantly higher than normal referenced score (t=9.331, P<0.001. The age, length of military service, years at present post of submariners were related

  3. Selective transport of palynomorphs in marine turbiditic deposits: An example from the Ascension-Monterey Canyon system offshore central California

    Science.gov (United States)

    McGann, Mary

    2017-01-01

    The pollen assemblage of a deep-sea core (15G) collected at lower bathyal depths (3491 m) on a levee of Monterey Canyon off central California was investigated to gain insights into the delivery processes of terrigenous material to submarine fans and the effect this transport has on the palynological record. Thirty-two samples were obtained down the length of the core, 19 from hemipelagic and mixed mud deposits considered to be the background record, and 13 others from displaced flow deposits. The pollen record obtained from the background samples documents variations in the terrestrial flora as it adapted to changing climatic conditions over the last 19,000 cal yrs BP. A Q-mode cluster analysis defined three pollen zones: a Glacial Pollen Zone (ca. 20,000–17,000 cal yr BP), an overlying Transitional Pollen Zone (ca. 17,000–11,500 cal yr BP), and an Interglacial Pollen Zone (ca. 11,500 cal yr BP to present). Another Q-mode cluster analysis, of both the background mud and flow deposits, also defined these three pollen zones, but four of the 13 turbiditic deposits were assigned to pollen zones older than expected by their stratigraphic position. This was due to these samples containing statistically significant fewer palynomorphs than the background muds as well as being enriched (∼10–35% in some cases) in hydraulically-efficient Pinus pollen. A selective bias in the pollen assemblage, such as demonstrated here, may result in incorrect interpretations (e.g., climatic shifts or environmental perturbations) based on the floral record, indicating turbiditic deposits should be avoided in marine palynological studies. Particularly in the case of fine-grained flow deposits that may not be visually distinct, granulometry and grain size frequency distribution curves may not be enough to identify these biased deposits. Determining the relative abundance and source of displaced shallow-water benthic foraminifera entrained in these sediments serves as an excellent

  4. The Mechanical Impact of Aerodynamic Stall on Tunnel Ventilation Fans

    Directory of Open Access Journals (Sweden)

    A. G. Sheard

    2012-01-01

    Full Text Available This paper describes work aimed at establishing the ability of a tunnel ventilation fan to operate without risk of mechanical failure in the event of aerodynamic stall. The research establishes the aerodynamic characteristics of a typical tunnel ventilation fan when operated in both stable and stalled aerodynamic conditions, with and without an anti-stall stabilisation ring, with and without a “nonstalling” blade angle and at full, half, and one quarter design speed. It also measures the fan’s peak stress, thus facilitating an analysis of the implications of the experimental results for mechanical design methodology. The paper concludes by presenting three different strategies for tunnel ventilation fan selection in applications where the selected fan will most likely stall. The first strategy selects a fan with a low-blade angle that is nonstalling. The second strategy selects a fan with a high-pressure developing capability. The third strategy selects a fan with a fitted stabilisation ring. Tunnel ventilation system designers each have their favoured fan selection strategy. However, all three strategies can produce system designs within which a tunnel ventilation fan performs reliably in-service. The paper considers the advantages and disadvantages of each selection strategy and considered the strengths and weaknesses of each.

  5. K-pop Reception and Participatory Fan Culture in Austria

    Directory of Open Access Journals (Sweden)

    Sang-Yeon Sung

    2013-12-01

    Full Text Available K-pop’s popularity and its participatory fan culture have expanded beyond Asia and become significant in Europe in the past few years. After South Korean pop singer Psy’s “Gangnam Style” music video topped the Austrian chart in October 2012, the number and size of K-pop events in Austria sharply increased, with fans organizing various participatory events, including K-pop auditions, dance festivals, club meetings, quiz competitions, dance workshops, and smaller fan-culture gatherings. In the private sector, longtime fans have transitioned from participants to providers, and in the public sector, from observers to sponsors. Through in-depth interviews with event organizers, sponsors, and fans, this article offers an ethnographic study of the reception of K-pop in Europe that takes into consideration local interactions between fans and Korean sponsors, perspectives on the genre, patterns of social integration, and histories. As a case study, this research stresses the local situatedness of K-pop fan culture by arguing that local private and public sponsors and fans make the reception of K-pop different in each locality. By exploring local scenes of K-pop reception and fan culture, the article demonstrates the rapidly growing consumption of K-pop among Europeans and stresses multidirectional understandings of globalization.

  6. On limited fan-in optimal neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.; Makaruk, H.E. [Los Alamos National Lab., NM (United States); Draghici, S. [Wayne State Univ., Detroit, MI (United States). Vision and Neural Networks Lab.

    1998-03-01

    Because VLSI implementations do not cope well with highly interconnected nets the area of a chip growing as the cube of the fan-in--this paper analyses the influence of limited fan in on the size and VLSI optimality of such nets. Two different approaches will show that VLSI- and size-optimal discrete neural networks can be obtained for small (i.e. lower than linear) fan-in values. They have applications to hardware implementations of neural networks. The first approach is based on implementing a certain sub class of Boolean functions, IF{sub n,m} functions. The authors will show that this class of functions can be implemented in VLSI optimal (i.e., minimizing AT{sup 2}) neural networks of small constant fan ins. The second approach is based on implementing Boolean functions for which the classical Shannon`s decomposition can be used. Such a solution has already been used to prove bounds on neural networks with fan-ins limited to 2. They generalize the result presented there to arbitrary fan-in, and prove that the size is minimized by small fan in values, while relative minimum size solutions can be obtained for fan-ins strictly lower than linear. Finally, a size-optimal neural network having small constant fan-ins will be suggested for IF{sub n,m} functions.

  7. CFD Models of a Serpentine Inlet, Fan, and Nozzle

    Science.gov (United States)

    Chima, R. V.; Arend, D. J.; Castner, R. S.; Slater, J. W.; Truax, P. P.

    2010-01-01

    Several computational fluid dynamics (CFD) codes were used to analyze the Versatile Integrated Inlet Propulsion Aerodynamics Rig (VIIPAR) located at NASA Glenn Research Center. The rig consists of a serpentine inlet, a rake assembly, inlet guide vanes, a 12-in. diameter tip-turbine driven fan stage, exit rakes or probes, and an exhaust nozzle with a translating centerbody. The analyses were done to develop computational capabilities for modeling inlet/fan interaction and to help interpret experimental data. Three-dimensional Reynolds averaged Navier-Stokes (RANS) calculations of the fan stage were used to predict the operating line of the stage, the effects of leakage from the turbine stream, and the effects of inlet guide vane (IGV) setting angle. Coupled axisymmetric calculations of a bellmouth, fan, and nozzle were used to develop techniques for coupling codes together and to investigate possible effects of the nozzle on the fan. RANS calculations of the serpentine inlet were coupled to Euler calculations of the fan to investigate the complete inlet/fan system. Computed wall static pressures along the inlet centerline agreed reasonably well with experimental data but computed total pressures at the aerodynamic interface plane (AIP) showed significant differences from the data. Inlet distortion was shown to reduce the fan corrected flow and pressure ratio, and was not completely eliminated by passage through the fan

  8. "The florals": Female fans over 50 in the Sherlock fandom

    OpenAIRE

    Line Nybro Petersen

    2017-01-01

    This article uses e-mail interviews with nine female fans to explore what it means to be a fan over the age of 50 of the popular BBC drama Sherlock (2010–). The research aims to better understand the role of fandom in later life, in particular how the participants in this study negotiate their perceptions of their subjective age in relation to being a fan in this part of their life course. This study combines theory on cultural gerontology with fan studies and mediatization theory in order to...

  9. Gender constructions and negotiations of female football fans

    DEFF Research Database (Denmark)

    Lenneis, Verena; Pfister, Gertrud Ursula

    2015-01-01

    While both the media and the academic literature focus primarily on male fans, in particular on violence and the prevention of hooliganism, little is known about female football supporters. This is also true of Denmark, a country that is known for its high degree of gender equality. This article...... by the female fans themselves. Female fans have to comply with specific rules of conduct in the stadium, where "masculine" behaviour for both male and female supporters is regarded as ideal fan behaviour. However, there is also space for gender negotiations as long as female supporters display neither...

  10. A measuring stand for a ducted fan aircraft propulsion unit

    Directory of Open Access Journals (Sweden)

    Hlaváček David

    2014-03-01

    Full Text Available The UL-39 ultra-light aircraft which is being developed by the Department of Aerospace Engineering, Faculty of Mechanical Engineering, Czech Technical University in Prague, is equipped with an unconventional ducted fan propulsion unit. The unit consists of an axial fan driven by a piston engine and placed inside a duct ended with a nozzle. This article describes the arrangement of a modernised measuring stand for this highly specific propulsion unit which will be able to measure the fan pressure ratio and velocity field in front of and behind the fan and its characteristic curve.

  11. Perancangan Interior Manchester United Fans Club Di Surabaya

    OpenAIRE

    Adinata, Rama

    2015-01-01

    Currently football has become the most popular sport in the world, it is directly proportional to the number of the fan club. Each fan club definitely needs a good place to gather it to share information, chat and even to watch the match together. Manchester United is the English football club that has the highest number of fan club in Indonesia. Therefore, in this thesis project a basecamp to accommodate the needs of the fan club Manchester United. The basecamp has several facilities such as...

  12. From submarine to lacustrine groundwater discharge

    Science.gov (United States)

    Lewandowski, Jörg; Meinikmann, Karin; Pöschke, Franziska; Nützmann, Gunnar; Rosenberry, Donald O.

    2017-01-01

    Submarine groundwater discharge (SGD) and its role in marine nutrient cycling are well known since the last decade. The freshwater equivalent, lacustrine groundwater discharge (LGD), is often still disregarded, although first reports of LGD are more than 50 years old. We identify nine different reasons why groundwater has long been disregarded in both freshwater and marine environments such as invisibility of groundwater discharge, the size of the interface and its difficult accessibility. Although there are some fundamental differences in the hydrology of SGD and LGD, caused primarily by seawater recirculation that occurs only in cases of SGD, there are also a lot of similarities such as a focusing of discharge to near-shore areas. Nutrient concentrations in groundwater near the groundwater–surface water interface might be anthropogenically enriched. Due to spatial heterogeneity of aquifer characteristics and biogeochemical processes, the quantification of groundwater-borne nutrient loads is challenging. Both nitrogen and phosphorus might be mobile in near-shore aquifers and in a lot of case studies large groundwater-borne nutrient loads have been reported.

  13. Design and analysis of submarine radome

    Science.gov (United States)

    Sandeep, C. Satya; Prasad, U. Shiva; Suresh, R.; Rathan, A.; Sravanthi, G.; Govardhan, D.

    2017-07-01

    Radomes are the electromagnetic windows that protect microwave sub-systems from the environmental effects. The major requirement of radome is its transparency to microwaves and for most of the cases mechanical properties are also equally important. Radome for underwater applications has to withstand high water pressure of the order of 45 bars. Composite materials owing to their high strength to weight ratio, high stiffness and better corrosion resistance are potential source for under water applications. The concept of 'tailoring' the material properties to suit the radome is obtained by selecting proper reinforcement, resin matrix and their compositions. The mechanical properties of composite material, evaluated by testing specimens as per ASTM standards, are utilized in designing the radome. The modulus properties calculated using classical theories of composite materials and compared with test results. ANSYS a Finite Element software package used to analyse the problem. As the cross sectional thickness of radome varies, the complexity in fabrication is overcome by adopting matched die techniques. The radome design and finite element analysis validation concluded by conducting the pressure test on radome. On the design a modal analysis is also carried to check for the natural frequency, So that resonance does not occur if the natural frequency of the radome coincides with the excitation frequency of the submarine Clinical information system (CIS) for UNRWA is a computerized distributed application that used in clinics which follows the United Nations Relief and Works Agency (UNRWA) to manage the clinical requirements and services.

  14. Seismic reflections associated with submarine gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Andreassen, K.

    1995-12-31

    Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom simulating reflection (BSR). To investigate the nature of BSR, this work uses seismic studies of hydrate-related BSRs at two different locations, one where gas hydrates are accepted to exist and interpreted to be very extensive (in the Beaufort Sea), the other with good velocity data and downhole logs available (offshore Oregon). To ascertain the presence of free gas under the BSR, prestack offset data must supplement near-vertical incidence seismic data. A tentative model for physical properties of sediments partially saturated with gas hydrate and free gas is presented. This model, together with drilling information and seismic data containing the BSR beneath the Oregon margin and the Beaufort Sea, made it possible to better understand when to apply the amplitude-versus-offset (AVO) method to constrain BSR gas hydrate and gas models. Distribution of natural gas hydrates offshore Norway and Svalbard is discussed and interpreted as reflections from the base of gas hydrate-bearing sediments, overlying sediments containing free gas. Gas hydrates inferred to exist at the Norwegian-Svalbard continental margin correlate well with Cenozoic depocenters, and the associated gas is assumed to be mainly biogenic. Parts of that margin have a high potential for natural gas hydrates of both biogenic and thermogenic origin. 235 refs., 86 figs., 4 tabs.

  15. Prodigious submarine landslides during the inception and early growth of volcanic islands.

    Science.gov (United States)

    Hunt, James E; Jarvis, Ian

    2017-12-12

    Volcanic island inception applies large stresses as the ocean crust domes in response to magma ascension and is loaded by eruption of lavas. There is currently limited information on when volcanic islands are initiated on the seafloor, and no information regarding the seafloor instabilities island inception may cause. The deep sea Madeira Abyssal Plain contains a 43 million year history of turbidites among which many originate from mass movements in the Canary Islands. Here, we investigate the composition and timing of a distinctive group of turbidites that we suggest represent a new unique record of large-volume submarine landslides triggered during the inception, submarine shield growth, and final subaerial emergence of the Canary Islands. These slides are predominantly multi-stage and yet represent among the largest mass movements on the Earth's surface up to three or more-times larger than subaerial Canary Islands flank collapses. Thus whilst these deposits provide invaluable information on ocean island geodynamics they also represent a significant, and as yet unaccounted, marine geohazard.

  16. Gas Hydrate Formation Amid Submarine Canyon Incision: Investigations From New Zealand's Hikurangi Subduction Margin

    Science.gov (United States)

    Crutchley, G. J.; Kroeger, K. F.; Pecher, I. A.; Mountjoy, J. J.; Gorman, A. R.

    2017-12-01

    We investigate gas hydrate system dynamics beneath a submarine canyon on New Zealand's Hikurangi subduction margin using seismic reflection data and petroleum systems modeling. High seismic velocities just above the base of gas hydrate stability (BGHS) indicate that concentrated gas hydrates exist beneath the canyon. Two-dimensional gas hydrate formation modeling shows how the process of canyon incision at this location alters the distribution and concentration of gas hydrate. The key modeling result is that free gas is trapped beneath the gas hydrate layer and then "captured" into a concentrated gas hydrate deposit as a result of a downward-shift in the BGHS driven by canyon incision. Our study thus provides new insight into the functioning of this process. From our data, we also conceptualize two other models to describe how canyons could significantly change gas hydrate distribution and concentration. One scenario is related to deflection of fluid flow pathways from over-pressured regions at the BGHS toward the canyon, and the other is based on relationships between simultaneous seafloor uplift and canyon incision. The relationships and processes described are of global relevance because of considerations of gas hydrate as an energy resource and the influence of both submarine canyons and gas hydrate systems on seafloor biodiversity.

  17. Submarine geology of South Kona landslide complex: investigation using ROV Kaiko

    Science.gov (United States)

    Yokose, H.; Yoshida, S.

    2002-12-01

    KR01-12 cruise of Japan Marine Science and Technology Center using ROV KAIKO and its mother ship R/V KAIREI were carried out around Hawaii islands in the early fall of 2001. During this cruise, two dives of ROV KAIKO were made on western submarine flank of the island of Hawaii: South Kona landslide complex (K210:proximal part of the south Kona landslide, K211: distal block of the landslide). One single channel seismic reflection line was collected from vicinity of the above dive sites. These areas have never been systematically studied using submersible due to the bad sea state and /or the depth of outcrops. Valuable information about the submarine geology and in situ rock samples from western franks of the island of Hawaii were obtained. K211 site is one of the distal landslide block and can be divided into 3 geological units from bottom to top: picritic sheet lava and hyaloclastite, volcaniclastic deposit with picritic breccia, muddy breccia with highly vesiculated ol basalt. On the other hand, rocks recovered from K210 are composed mainly of aa clinker and aa lava which are highly vesiculated and reddish in color. The rocks from K210 is similar to the upper part of K211 in their bulk rock chemistry. Based on the geological and bulk rock chemistry, rocks recovered from both sites should be erupted subaerially. It suggests that these landslide blocks were composed subaerial portion of the paleo-Mauna Loa volcano.

  18. Submarine Channel Association with Seamount Chain Alignment on the Ontong Java Plateau

    Science.gov (United States)

    Meyers, H. G., IV; Sautter, L.

    2016-02-01

    The Ontong Java Plateau (OJP), north of the Solomon Islands, Indonesia, is a submerged seafloor platform, larger than Alaska and full of intricate systems of channels, atolls and seamounts. This area has remained relatively unstudied because of both the area's remote location and low number of ships carrying advanced sonar systems. The OJP is believed to have been formed by one of the largest volcanic eruptions in Earth's history. This study uses EM302 multibeam sonar data collected on the R/V Falkor in 2014 by the University of Tasmania's Institute for Marine and Antarctic Studies to better understand relationships between the seafloor geomorphology and tectonic processes that formed numerous unexplored seamounts. The area surveyed is situated along the OJP's central northeast margin, and includes a small chain of six seamounts that range from 300 to 700 m in vertical relief. These seamounts are situated within the axis of a major 14 km wide submarine channel that was likely formed by a sequence of turbidity currents. Using CARIS HIPS and SIPS 9.0 post-processing software, seamount and channel morphology were characterized with 2 dimensional profiles and 3 dimensional images. Backscatter intensity was used to identify relative substrate hardness of the seamounts and surrounding seafloor areas. Scour and depositional features from the turbidity flows are evident at the base of several seamounts, indicating that the submarine channel bifurcated when turbidity flows encountered the seamount chain.

  19. Drive elements for fans; Antriebselemente fuer Ventilatoren

    Energy Technology Data Exchange (ETDEWEB)

    Lexis, J. [Gebhardt Ventilatoren, Feucht bei Nuernberg (Germany)

    1999-09-01

    The belt drive is one of the most important drive elements in ventilation and air-conditioning engineering, respectively in fan technology. The article deals in detail with the advantages and disadvantages of the V-belt, respectively flat belt, as well as complete computation of a V-belt drive. (orig.) [German] In der Lueftungs- und Klimatechnik bzw. Ventilatortechnik ist der Riemenantrieb eines der wichtigsten Antriebselemente. Es wird auf die Vor- und Nachteile von Keil- bzw. Flachriemen sowie auf die komplette Berechnung eines Keilriemenantriebes naeher eingegangen. (orig.)

  20. Characteristics and features of the submarine landslides in passive and active margin southwestern offshore Taiwan

    Science.gov (United States)

    Yeh, Y. C.

    2016-12-01

    deposits (MTDs) were identified in deeper stratigraphic section below BSR. This indicated several big former submarine landslide events occurred. In summary, the passive margin often show typical submarine landslide features than active margin, which driven by gravity force.

  1. NSMRL: A Small Command with A Huge Presence for the Submarine Force

    National Research Council Canada - National Science Library

    Daniel, J. C; Lamb, Jerry

    2005-01-01

    "To protect the health and enhance the performance of our warfighters through focused submarine, diving and surface research solutions" is the mission of the Naval Submarine Medical Research Laboratory (NSMRL...

  2. Identifying the "Foot of the Continental Slope" of high-latitude continental margins influenced by trough mouth fans

    Science.gov (United States)

    Sverre Laberg, Jan

    2017-04-01

    The continental slope of high-latitude margins often include trough mouth fans, which are sediment fans situated in front of large troughs crossing the continental shelf. The troughs acted as corridors for paleo-ice streams, sectors of fast-flowing ice within the large ice sheets of the last glacial maximum as well as previous glacials. The paleo-ice streams were highly efficient erosional agents, eroding and transporting large volumes of sediments to the continental shelf edge. Here, these sediments were released to move downslope as large debris flows, the "building blocks" of these fans. Due to the very large sediment volume included within these fans, they represent prominent depocenters forming low-gradient sectors (axial gradient often being as low as 1 degree or less) with no clear morphological distinction of the continental slope including its lower limit. Under the UN Convention on the Law of the Sea, the criteria provided in Article 76 includes the lower limit or "foot" of the continental slope as one important parameter in the extended Continental Shelf delineation (i.e. beyond the 200 M exclusive economic zone). Because of this, the Norwegian submission regarding the outer limits of the continental shelf in the Norwegian Sea and the Arctic Ocean argued that the origin of the sub-sea floor sediments on the slope needed to be considered when identifying the location of the foot of the continental slope. This was done by mapping the outer limits of the large debris flow deposits of the trough mouth fans, deposits that without doubt have their origin from the continental shelf. Thus, in these cases, the foot of the continental slope coincide with the downslope termination of the large debris flow deposits and the outer limit of the continental shelf lies 60 M beyond this point. The data used for mapping includes swath bathymetry, sub-bottom profiles and short sediment samples (< 10 m), and we present and discuss examples from the Bear Island Trough Mouth

  3. Submarine flow discharge changes as a way to explain incission-overspilling and other cycles in submarine channel sequences

    Science.gov (United States)

    Milana, J. P.; Kneller, B.; Dykstra, M.

    2009-04-01

    -stratification. The second bedform recognized is related to described macrodunes, and is comparable to large-scale antidunes, and produce tabular bodies with very subtle undulating structure. The third and perhaps more important is described as "gravel sheets" although they could be also low-relief gravel dunes developed during low-flow events, on top of the large-scale bedforms or directly over a flat gravelly bed. It is well known that bedforms produce the effect of delay averaged sediment velocity with respect to flow velocity, and thus we propose that this delay has an important geological effect as it creates a lag time between the onset of discharge increase and the time the channel bed reaches an equilibrium with the dominant flows. The effect of changes in the transport efficiency of submarine slope systems in the resulting depositional architecture is already known. However, we introduce here the concept of lagging the coarsest-grained fractions, delayed by the fact they involve in bedform building which move at lower velocities of the flows and hence allow the system to pass along a stage in which flows are big and fast, but the bed is not in equilibrium with them and as a result, canyoning may occur. These changes in external conditions (flow discharge) is likely to occur as a result of changes of turbid water near the slope by fluvial action and hence it would be t result of the interplay of river discharge and eustacy.

  4. Experimental study of a single channel alluvial fan

    Science.gov (United States)

    Delorme, Pauline; Devauchelle, Olivier; Barrier, Laurie; Métivier, François

    2016-04-01

    At the outlet of mountain ranges, rivers reach a flat plain and start to depose their sediment load into a conical sedimentary structure called alluvial fan. To decipher these sedimentary records, we need to understand the dynamics of their growth. Most natural fans are built by braided streams. However, to avoid the complexity of braided rivers, we develop a small-scale experiment in which an alluvial fan is formed by a single channel. We use a mixture of water and glycerol to produce a laminar river. The fluid is mixed with corindon sand (~ 300 μm) in a tilted channel and left free to form a fan around its outlet. The sediment and water discharges are constant during an experimental run. We record the fan progradation and the channel morphology with top-view pictures. We also generate an elevation map with an optical method based on the deformation of a moiré pattern. We observe that, to leading order, the fan remains self-affine as it grows, with a constant slope. We compare two recent studies about the formation of one-dimensionnal fan [Guerit et al. 2014] and threshold rivers [Seizilles et al. 2013] to our experimental findings. In particular, we propose a theory witch relates the fan morphology to the control parameters (fluid and sediment discharges, grain size). Our observations accord with the predictions, suggesting that the fan is built near the threshold of sediment motion. At the first order, the fan profile is linear and control by the water discharge. The downstream decrease in sediment discharge add a curvature to this profile. Finally, we intend to expand our interpretation to alluvial fans build by single-thread channels ( Okavango, Bostwana; Taquari and Paraguay, Brasil).

  5. Multiple Episodes of Recent Gully Activity Indicated by Gully Fan Stratigraphy in Eastern Promethei Terra, Mars.

    Science.gov (United States)

    Schon, S.; Head, J.; Fassett, C.

    2008-09-01

    Introduction Gullies are considered among the youngest geomorphic features on Mars based upon their stratigraphic relationships, superposition on steep slopes and distinctive morphology in unconsolidated sediment. Multiple formation hypotheses have been proposed, which can be divided into three broad classes: entirely dry mechanisms (e.g., [1,2]), wet mechanisms invoking groundwater or ground ice (e.g., [3,4]) and wet mechanisms invoking surficial meltwater (e.g., [5,6,7,8]). It has been difficult to differentiate between these hypotheses based upon past observations and it remains possible that gullies are polygenetic landforms. This study presents stratigraphic relationships in the depositional fan of a crater wall gully system that suggest: (1) multiple episodes of alluvial fan-style deposition, (2) very recent depositional activity that is younger than a newly recognized rayed crater, and (3) surficial snowmelt as the most likely source of these multiple episodes of recent gully activity. Gully-Fan Stratigraphy In Eastern Promethei Terra an ~5 km-diameter crater is observed with a well-developed gully system (Fig. 1) and several smaller gullies in its northnortheast wall. The large gully system (composed of a small western gully and larger eastern gully) shows evidence for incision into the crater wall country rock and has multiple contributory sub-alcoves and channels. The depositional fan associated with this gully system is bounded on its western side by a small arcuate ridge swell that is not observed on the eastern side of the fan. This ridge is interpreted as a moraine-like structure that may have bounded a glacially-formed depression into which the fan is deposited [8]. Similar depressions with bounding ridges are commonly observed in this latitude band (~30-50°S) in association with deeply incised gully alcoves [9,10,11]. This gully fan is composed of multiple lobes with distinct lobe contacts, incised channels, and cut-andfill deposits - all features

  6. Conduct and Support of Amphibious Operations from United States Submarines in World War II

    Science.gov (United States)

    2010-11-01

    twelfth war patrol of the Gato class submarine (See photos 1 and 2). They made history as the only Americans to conduct an offensive landing on a...Naval History Vol. 2, no. 1 (April 1, 2003), 1. 4 This monograph features five Gato class submarines, and three V-class submarines, but also addresses...1993), 67. 6 Photo 2: USS Barb (SS 220), representing the five Gato class submarines that participated in Operation Torch. Barb’s crew also

  7. Index of Submarine Medical Officer’s Qualification Theses 1944-1974

    Science.gov (United States)

    1976-04-01

    DEAD SPACE MEASUREMENTS BEFCRE AND 1968-3009 -- ESP IRATORY DEAD SPACE VARIAION TUDINVL---t b-0 9 INJURIES ON+ A SYLLABUS DEALING WITH THE MANAGEMENT OF...SUBARIkNE MEDICINEO A SYLLABUS OF.- SUBMARINE MEDICAL QUALIFICATION THESES U. S. NAVAL SJBMARINE MEDICAL CENTER SUBMARIN BASE, NEW LCNOOjN, GROTON...CARBON DIOXIDE ABSORBENT EVALUATION AND CANNISTER DESIGN *= SUBMARINE MDCLUALIFICATICN THESES U. -S.NAVAL SUBMARE MEDICAL CENTER SUBMARINE BASE, NEW LCNDON

  8. Featured Image: Waves in a Coronal Fan

    Science.gov (United States)

    Kohler, Susanna

    2017-09-01

    The inset in this Solar Dynamics Observatory image shows a close-up view of a stunning coronal fan extending above the Suns atmosphere. These sweeping loops were observed on 7 March 2012 by a number of observatories, revealing the first known evidence of standing slow magnetoacoustic waves in cool coronal fan loops. The oscillations of the loops, studied in a recent article led by Vaibhav Pant (Indian Institute of Astrophysics), were triggered by blast waves that were generated by X-class flares from the distant active region AR 11429 (marked withthe yellow box at left). The overplotted X-ray curve in the top right corner of the image (click for the full view) shows the evolution of the flares that perturbed the footpoints of the loops. You can check out the video of the action below, and follow the link to the original article to read more about what these oscillations tell us about the Suns activity. CitationV. Pant et al 2017 ApJL 847 L5. doi:10.3847/2041-8213/aa880f

  9. Acidic Shell Proteins of the Mediterranean Fan Mussel Pinna nobilis.

    Science.gov (United States)

    Marin, Frédéric; Narayanappa, Prabakaran; Motreuil, Sébastien

    2011-01-01

    In molluscs, the shell secretion process is controlled by a set of extracellular macromolecules collectively called the shell matrix. The shell matrix, which is produced by the mantle epithelial cells during mineralization, is predominantly composed of proteins, glycoproteins, acidic polysaccharides, and chitin that precisely regulate the deposition of calcium carbonate outside the mantle cells. In the present paper, we focus on the shell of Pinna nobilis, the giant Mediterranean fan mussel, usually considered as a model for studying molluscan biomineralization processes. P. nobilis exhibits indeed a nacro-prismatic shell, the outer layer of which is constituted of the so-called "regular simple calcitic prisms," according to Carter and Clark (1985). We review here the microstructural characteristics of the prisms and nacre and the biochemical properties of their associated matrices. In particular, the calcitic prisms of P. nobilis are characterized by a cortege of unusually acidic intraprismatic proteins, while the ones of the nacreous layer seem less acidic. A brief description of the molecular characterization of three acidic proteins, caspartin, calprismin and mucoperlin, is given. In particular, we show that extremely acidic intracrystalline proteins such as caspartin interact with calcium carbonate at different scales, from micrometric to crystal lattice levels.

  10. Quaternary fans and terraces in the Khumbu Himal south of Mount Everest: their characteristics, age and formation

    Science.gov (United States)

    Barnard, P.L.; Owen, L.A.; Finkel, R.C.

    2006-01-01

    Large fans and terraces are frequent in the Khumbu Himal within the high Himalayan valleys south of Mt. Everest. These features are composed of massive matrix- and clast-supported diamicts that were formed from both hyperconcentrated flows and coarse-grained debris flows. Cosmogenic radionuclide (CRN) exposure ages for boulders on fans and terraces indicate that periods of fan and terrace formation occurred at c. 16, c. 12, c. 8, c. 4 and c. 1.5 ka, and are broadly coincident with the timing of glaciation in the region. The dating precision is insufficient to resolve whether the surfaces formed before, during or after the correlated glacial advance. However, the sedimentology, and morphostratigraphic and geomorphological relationships suggest that fan and terrace sedimentation in this part of the Himalaya primarily occurs during glacier retreat and is thus paraglacial in origin. Furthermore, modern glacial-lake outburst floods and their associated deposits are common in the Khumbu Himal as the result of glacial retreat during historical times. We therefore suggest that Late Quaternary and Holocene fan and terrace formation and sediment transfer are probably linked to temporal changes in discharge and sediment load caused by glacier oscillations responding to climate change. The timing of major sedimentation events in this region can be correlated with fans and terraces in other parts of the Himalaya, suggesting that major sedimentation throughout the Himalaya is synchronous and tied to regional climatic oscillations. Bedrock incision rates calculated from strath terrace ages average c. 3.9 mm a−1, suggesting that the overall rate of incision is set by regional uplift.

  11. Linking the morphology of fluvial fan systems to aquifer stratigraphy in the Sutlej-Yamuna plain of northwest India

    Science.gov (United States)

    van Dijk, W. M.; Densmore, A. L.; Singh, A.; Gupta, S.; Sinha, R.; Mason, P. J.; Joshi, S. K.; Nayak, N.; Kumar, M.; Shekhar, S.; Kumar, D.; Rai, S. P.

    2016-02-01

    The Indo-Gangetic foreland basin has some of the highest rates of groundwater extraction in the world, focused in the states of Punjab and Haryana in northwest India. Any assessment of the effects of extraction on groundwater variation requires understanding of the geometry and sedimentary architecture of the alluvial aquifers, which in turn are set by their geomorphic and depositional setting. To assess the overall architecture of the aquifer system, we used satellite imagery and digital elevation models to map the geomorphology of the Sutlej and Yamuna fan systems, while aquifer geometry was assessed using 243 wells that extend to ˜200 m depth. Aquifers formed by sandy channel bodies in the subsurface of the Sutlej and Yamuna fans have a median thickness of 7 and 6 m, respectively, and follow heavy-tailed thickness distributions. These distributions, along with evidence of persistence in aquifer fractions as determined from compensation analysis, indicate persistent reoccupation of channel positions and suggest that the major aquifers consist of stacked, multistoried channel bodies. The percentage of aquifer material in individual boreholes decreases down fan, although the exponent on the aquifer body thickness distribution remains similar, indicating that the total number of aquifer bodies decreases down fan but that individual bodies do not thin appreciably, particularly on the Yamuna fan. The interfan area and the fan marginal zone have thinner aquifers and a lower proportion of aquifer material, even in proximal locations. We conclude that geomorphic setting provides a first-order control on the thickness, geometry, and stacking pattern of aquifer bodies across this critical region.

  12. Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress

    Science.gov (United States)

    2016-04-05

    Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine Program: Background and Issues for Congress Ronald O’Rourke Specialist in Naval...Affairs April 5, 2016 Congressional Research Service 7-5700 www.crs.gov R41129 Navy Ohio Replacement (SSBN[X]) Ballistic Missile Submarine...Replacement (SSBN[X]) Ballistic Missile Submarine Program Congressional Research Service Contents Introduction

  13. Using Fan Fiction to Teach Critical Reading and Writing Skills

    Science.gov (United States)

    Kell, Tracey

    2009-01-01

    In this article, the author talks about fan fiction, which is defined by Jenkins (2008) as "original stories and novels which are set in the fictional universe of favorite television series, films, comics, games or other media properties." Fan fiction generally involves writing stories with a combination of established characters and established…

  14. Acoustic Measurements of an Uninstalled Spacecraft Cabin Ventilation Fan Prototype

    Science.gov (United States)

    Koch, L. Danielle; Brown, Clifford A.; Shook, Tony D.; Winkel, James; Kolacz, John S.; Podboy, Devin M.; Loew, Raymond A.; Mirecki, Julius H.

    2012-01-01

    Sound pressure measurements were recorded for a prototype of a spacecraft cabin ventilation fan in a test in the NASA Glenn Acoustical Testing Laboratory. The axial fan is approximately 0.089 m (3.50 in.) in diameter and 0.223 m (9.00 in.) long and has nine rotor blades and eleven stator vanes. At design point of 12,000 rpm, the fan was predicted to produce a flow rate of 0.709 cu m/s (150 cfm) and a total pressure rise of 925 Pa (3.72 in. of water) at 12,000 rpm. While the fan was designed to be part of a ducted atmospheric revitalization system, no attempt was made to throttle the flow or simulate the installed configuration during this test. The fan was operated at six speeds from 6,000 to 13,500 rpm. A 13-microphone traversing array was used to collect sound pressure measurements along two horizontal planes parallel to the flow direction, two vertical planes upstream of the fan inlet and two vertical planes downstream of the fan exhaust. Measurements indicate that sound at blade passing frequency harmonics contribute significantly to the overall audible noise produced by the fan at free delivery conditions.

  15. Sediment Fan Evolution and Hydrologic Activity in Mojave Crater, Mars

    Science.gov (United States)

    Goddard, K.; Gupta, S.; Densmore, A. L.; Kim, J.-R.; Warner, N. H.; Carbonneau, P.; Muller, J.-P.

    2011-03-01

    Catchment-fans with channel networks have been observed in Mojave Crater, Mars. We used a ~1m resolution HiRISE DTM to look at fan formation processes and past water activity. We have observed geomorphology suggesting episodic water availability.

  16. Construction of an automated temperature sensing electric fan ...

    African Journals Online (AJOL)

    The achieved results and its features when compared with available electric fan indicate that there will be a great demand for the product if it is introduced to the market since everybody cannot afford an air-conditioner due to its high cost. Key words: Temperature, Fan Regulator, C++ programming, Analogue-to-Digital ...

  17. Dimensions of attachment among fans within the South African ...

    African Journals Online (AJOL)

    ... reflecting both its practical application and statistical reliability which can be used to measure and understand fans' attachment and identification within the soccer fraternity. Limitations and implications for further research are outlined. Key words: Soccer fans, attachment, identification, loyalty, social identity theory.

  18. Amateur mythographies: Fan fiction and the myth of myth

    Directory of Open Access Journals (Sweden)

    Ika Willis

    2016-03-01

    Full Text Available This paper draws on classical scholarship on myth in order to critically examine three ways in which scholars and fans have articulated a relationship between fan fiction and myth. These are (1 the notion of fan fiction as a form of folk culture, reclaiming popular story from corporate ownership; (2 the notion of myth as counterhegemonic, often feminist, discourse; (3 the notion of myth as a commons of story and a universal story world. I argue that the first notion depends on an implicit primitivizing of fan fiction and myth, which draws ultimately on the work of Gottfried von Herder in the 18th century and limits our ability to produce historically and politically nuanced understandings of fan fiction. The second notion, which is visible in the work of Henry Jenkins and Constance Penley, is more helpful because of its attention to the politics of narration. However, it is the third model of myth, as a universal story world, where we find the richest crossover between fan fiction's creative power and contemporary classical scholarship on myth, especially in relation to Sarah Iles Johnston's analysis of hyperserial narrative. I demonstrate this through some close readings of fan fiction from the Greek and Roman Mythology fandom on Archive of Our Own. I conclude the paper by extending Johnston's arguments to show that fan-fictional hyperseriality, specifically, can be seen as mythic because it intervenes not only in the narrative worlds of its source materials but also in the social world of its telling.

  19. Wikipedia and participatory culture: Why fans edit [symposium

    Directory of Open Access Journals (Sweden)

    Paul Thomas

    2016-09-01

    Full Text Available Online, fans of popular culture media partake in participatory culture in various ways, such as writing fan fiction and scrutinizing media on message boards. Another way they do so is by editing relevant articles in the online encyclopedia Wikipedia. In fact, research has shown that Wikipedia articles skew heavily toward pop culture, suggesting that fans of pop culture are among the most enthusiastic of Wikipedia's editors. Of course, the question emerges: Why are pop culture fans in particular so interested in editing Wikipedia? Building on previous research, I argue that fans want to take part in the production of the media that they enjoy, that Wikipedia allows editors to create their own paratext (i.e., the Wikipedia article in relation to a main text (e.g., a movie, a television show, a book series, and that this paratext may be heavily used by the general public. Such usage is a form of implicit approval that affirms the editors' knowledge and encourages them to make more edits. Thus, Wikipedia validates the fan editor's work in a way that other outlets for participatory culture (e.g., fan fiction, fan art, songwriting cannot.

  20. 30 CFR 75.302 - Main mine fans.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Main mine fans. 75.302 Section 75.302 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.302 Main mine fans. Each coal mine shall be...

  1. Dimensions of attachment among fans within the South African ...

    African Journals Online (AJOL)

    In the last decade there has been growing interest in the study of fans to better understand sport consumption behaviours, motives, attachment, loyalty and satisfaction. This study was aimed at ascertaining the various dimensions of attachment of fans within the South African Premier Soccer League (PSL). The secondary ...

  2. Precision forging of front fan blades, abridged version

    Science.gov (United States)

    Voigtlaender, O.; Degenhardt, H.

    1983-10-01

    The manufacturing of titanium alloy front fan blades with ready-for-assembly contact surfaces on conventional counterblow hammers is reported. Thermal contraction and elastic die-deformation were determined and the tooling was fabricated by computerized design. Forging trials give fan blades which dimensionally and metallurgically meet the requirements.

  3. High- and low-latitude forcing of the Nile River regime during the Holocene inferred from laminated sediments of the Nile deep-sea fan

    NARCIS (Netherlands)

    Blanchet, C.; Tjallingii, R.; Frank, M.; Lorenzen, J.; Reitz, A.; Brown, K.; Feseker, T.; Brückmann, W.

    2013-01-01

    Sediments deposited on deep-sea fans are an excellent geological archive to reconstruct past changes in fluvial discharge. Here we present a reconstruction of changes in the regime of the Nile River during the Holocene obtained using bulk elemental composition, grain-size analyses and radiogenic

  4. Case study of French and Spanish fan reception of Game of Thrones

    Directory of Open Access Journals (Sweden)

    Mélanie Bourdaa

    2015-06-01

    Full Text Available The reception of the American TV show Game of Thrones (2011– by French and Spanish fans and nonfans is addressed via a qualitative methodology, the goal of which is to understand how European viewers perceive themselves as fans and what it means for them to be fans. Analysis of characteristics of a specifically European reception helps us learn what fan studies tell us about fans and what fans really think about fandoms.

  5. Hydrodynamic modeling of magmatic-hydrothermal activity at submarine arc volcanoes, with implications for ore formation

    Science.gov (United States)

    Gruen, Gillian; Weis, Philipp; Driesner, Thomas; Heinrich, Christoph A.; de Ronde, Cornel E. J.

    2014-10-01

    Subduction-related magmas have higher volatile contents than mid-ocean ridge basalts, which affects the dynamics of associated submarine hydrothermal systems. Interaction of saline magmatic fluids with convecting seawater may enhance ore metal deposition near the seafloor, making active submarine arcs a preferred modern analogue for understanding ancient massive sulfide deposits. We have constructed a quantitative hydrological model for sub-seafloor fluid flow based on observations at Brothers volcano, southern Kermadec arc, New Zealand. Numerical simulations of multi-phase hydrosaline fluid flow were performed on a two-dimensional cross-section cutting through the NW Caldera and the Upper Cone sites, two regions of active venting at the Brothers volcanic edifice, with the former hosting sulfide mineralization. Our aim is to explore the flow paths of saline magmatic fluids released from a crystallizing magma body at depth and their interaction with seawater circulating through the crust. The model includes a 3 × 2km2 sized magma chamber emplaced at ∼ 2.5 km beneath the seafloor connected to the permeable cone via a ∼ 200 m wide feeder dike. During the simulation, a magmatic fluid was temporarily injected from the top of the cooling magma chamber into the overlying convection system, assuming hydrostatic conditions and a static permeability distribution. The simulations predict a succession of hydrologic regimes in the subsurface of Brothers volcano, which can explain some of the present-day hydrothermal observations. We find that sub-seafloor phase separation, inferred from observed vent fluid salinities, and the temperatures of venting at Brothers volcano can only be achieved by input of a saline magmatic fluid at depth, consistent with chemical and isotopic data. In general, our simulations show that the transport of heat, water, and salt from magmatic and seawater sources is partly decoupled. Expulsion of magmatic heat and volatiles occurs within the first

  6. Characteristics of an anechoic chamber for fan noise testing

    Science.gov (United States)

    Wazyniak, J. A.; Shaw, L. M.; Essary, J. D.

    1977-01-01

    Acoustical and mechanical design features of NASA Lewis Research Center's engine fan noise facility are described. Acoustic evaluation of the 1420-m (50,000-ft) chamber, which is lined with an array of stepped wedges, is described. Results from the evaluation in terms of cut-off frequency and non-anechoic areas near the walls are detailed. Fan models with 0.51-m (20-in) diameters are electrically driven to 20,600 rpm in either the inlet mode (drawing air from the chamber) or exhaust mode (discharging air into the chamber) to facilitate study of both fore and aft fan noise. Inlet noise characteristics of the first fan tested, the JT8D Refan, are discussed and compared to full-scale levels. Turbulence properties of the inlet flow and acoustic results are compared with and without a turbulence reducing screen over the fan inlet.

  7. Sports Fans, Alcohol Use, and Violent Behavior: A Sociological Review.

    Science.gov (United States)

    Ostrowsky, Michael K

    2016-08-31

    This review makes four contributions to the sociological study of sports fans, alcohol use, and violent behavior. First, this article focuses explicitly on the relationship between alcohol use and violent behavior among sports fans. This is a worldwide social problem, yet it is quite understudied. Second, this article synthesizes the fragmented literature on alcohol use and violent behavior among sports fans. Third, this article identifies four broad sets of risk factors-sociocultural, event/venue, police, and crowd-that appear to be closely related to violent behavior among sports fans. Finally, to help explain the possible correlation between alcohol and violence among sports fans, this article draws upon the key understandings from the literature on alcohol and violence in wider society. The article concludes with suggestions for future research. © The Author(s) 2016.

  8. Costs and benefits of energy efficiency improvements in ceiling fans

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Nihar; Sathaye, Nakul; Phadke, Amol; Letschert, Virginie [Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technology Division

    2013-10-15

    Ceiling fans contribute significantly to residential electricity consumption, especially in developing countries with warm climates. The paper provides analysis of costs and benefits of several options to improve the efficiency of ceiling fans to assess the global potential for electricity savings and green house gas (GHG) emission reductions. Ceiling fan efficiency can be cost-effectively improved by at least 50% using commercially available technology. If these efficiency improvements are implemented in all ceiling fans sold by 2020, 70 terawatt hours per year could be saved and 25 million metric tons of carbon dioxide equivalent (CO2-e) emissions per year could be avoided, globally. We assess how policies and programs such as standards, labels, and financial incentives can be used to accelerate the adoption of efficient ceiling fans in order to realize potential savings.

  9. Low Frequency Noise Contamination in Fan Model Testing

    Science.gov (United States)

    Brown, Clifford A.; Schifer, Nicholas A.

    2008-01-01

    Aircraft engine noise research and development depends on the ability to study and predict the noise created by each engine component in isolation. The presence of a downstream pylon for a model fan test, however, may result in noise contamination through pylon interactions with the free stream and model exhaust airflows. Additionally, there is the problem of separating the fan and jet noise components generated by the model fan. A methodology was therefore developed to improve the data quality for the 9 15 Low Speed Wind Tunnel (LSWT) at the NASA Glenn Research Center that identifies three noise sources: fan noise, jet noise, and rig noise. The jet noise and rig noise were then measured by mounting a scale model of the 9 15 LSWT model fan installation in a jet rig to simulate everything except the rotating machinery and in duct components of fan noise. The data showed that the spectra measured in the LSWT has a strong rig noise component at frequencies as high as 3 kHz depending on the fan and airflow fan exit velocity. The jet noise was determined to be significantly lower than the rig noise (i.e., noise generated by flow interaction with the downstream support pylon). A mathematical model for the rig noise was then developed using a multi-dimensional least squares fit to the rig noise data. This allows the rig noise to be subtracted or removed, depending on the amplitude of the rig noise relative to the fan noise, at any given frequency, observer angle, or nozzle pressure ratio. The impact of isolating the fan noise with this method on spectra, overall power level (OAPWL), and Effective Perceived Noise Level (EPNL) is studied.

  10. Life, death and revival of debris-flow fans on Earth and Mars : fan dynamics and climatic inferences

    NARCIS (Netherlands)

    de Haas, T.|info:eu-repo/dai/nl/374023190

    2016-01-01

    Alluvial fans are ubiquitous landforms in high-relief regions on Earth and Mars. They have a semi-conical shape and are located at the transition between highlands and adjacent basins. Alluvial fans can form by a range of processes including debris flows, which are water-laden masses of soil and

  11. Updated size distribution of submarine landslides along the U.S. Atlantic margin

    Science.gov (United States)

    Ten Brink, U. S.; Chaytor, J. D.; Andrews, B. D.; Brothers, D. S.; Geist, E. L.

    2012-12-01

    The volume of failed material in submarine landslides is one of the primary factors controlling tsunami amplitude, hence the cumulative volume distribution of submarine landslides on the U.S. Atlantic continental slope and rise provides information important for the evaluation of tsunami hazard potential for U.S. the East Coast. Landslide size distributions also help constrain the initiation mechanisms of submarine landslides in siliciclastic and carbonate environments [1,2], and thus improve our understanding of the pre-conditioning and propagation of landslides. Previous compilations of landslide distributions along the Atlantic continental margin used regional side-scan sonar data, seismic reflection profiles and multibeam bathymetry data that lacked coverage of large portions of the upper continental slope [3, 4]. We updated this regional database by compiling and merging multibeam echosounder data from 36 surveys conducted by various federal agencies and academia between Georges Banks and Cape Hatteras from 1990-2012. The result is a continuous 594,000 km2 digital bathymetric surface with a spatial resolution of 100 m spanning water depths between 55-6150 m. The new grid allows better identification and delineation of the areas and heights of the headwall scarps, and more precise volume estimates of the evacuated slide regions. Acoustic backscatter derived from the multibeam data and an updated compilation of sub-bottom seismic profiles and core logs improve the identification of the extent of mass transport deposits. The updated analysis includes uncertainties in the determination of the landslide areas. The cumulative area and volume distributions of the landslides excavations, their area/volume ratio, the water depth of the head wall, and the fraction of slope and rise areas covered by headwall scarps and landslide deposits, are quantified and discussed. Combining landslide size distribution with the overall rate of occurrence of landslides derived from age

  12. Method of fan sound mode structure determination

    Science.gov (United States)

    Pickett, G. F.; Sofrin, T. G.; Wells, R. W.

    1977-01-01

    A method for the determination of fan sound mode structure in the Inlet of turbofan engines using in-duct acoustic pressure measurements is presented. The method is based on the simultaneous solution of a set of equations whose unknowns are modal amplitude and phase. A computer program for the solution of the equation set was developed. An additional computer program was developed which calculates microphone locations the use of which results in an equation set that does not give rise to numerical instabilities. In addition to the development of a method for determination of coherent modal structure, experimental and analytical approaches are developed for the determination of the amplitude frequency spectrum of randomly generated sound models for use in narrow annulus ducts. Two approaches are defined: one based on the use of cross-spectral techniques and the other based on the use of an array of microphones.

  13. Variations in spatial patterns of soil-vegetation properties and the emergence of multiple resilience thresholds within different debris flow fan positions

    Science.gov (United States)

    Mohseni, Neda; Hosseinzadeh, Seyed Reza; Sepehr, Adel; Golzarian, Mahmood Reza; Shabani, Farzin

    2017-08-01

    Debris flow fans are non-equilibrium landforms resulting from the spatial variations of debris flows deposited on them. This geomorphic disturbance involving the asymmetric redistribution of water and sediment may create spatially heterogeneous patterns of soil-vegetation along landforms. In this research, founded on field-based observations, we characterized the spatial patterns of some soil (e.g., particle size distribution including fine and coarse covers, and infiltration capacity) and vegetation (e.g., plant distance, vegetation density, patch size, and average number of patches) properties within different debris flow fan positions (Upper, Middle, and Lower fan) located at the base of the Binaloud Mountain hillslope in northeastern Iran. Thereafter, using a mathematical model of dry land vegetation dynamics, we calculated response trends of the different positions to the same environmental harshness gradient. Field measurements of soil-vegetation properties and infiltration rates showed that the asymmetric redistribution of debris flow depositions can cause statistically significant differences (P fan plots. Conversely, an increase in infiltration rate was observed. The simulation results on the aerial images taken from different positions, illustrated that positions with a heterogeneous distribution of vegetation patterns were not desertified to the same degree of aridity. Thus, the Middle and Lower positions could survive under harsher aridity conditions, due to the emergence of more varied spatial vegetation patterns than at the Upper fan position. The findings, based on a combined field and modeling approach, highlighted that debris flow as a geomorphic process with the asymmetric distribution of depositions on the gentle slope of an alluvial fan, can incur multiple resilience thresholds with different degrees of self-organization under stressful conditions over the spatial heterogeneities of soil-dependent vegetation structures.

  14. Environmental magnetic studies on some Quaternary sediments of varied depositional settings in the Indian sub-continent

    Digital Repository Service at National Institute of Oceanography (India)

    Sangode, S.J.; Sinha, R.; Phartiyal, B.; Chauhan, O.S.; Mazari, R.K.; Bagati, T.N.; Suresh, N.; Mishra, S.; Kumar, R.; Bhattacharjee, P.

    fan region. The MMAs for the lacustrine and fluviolacustrine deposits in the Himalayan foothills as well as the Higher Himalaya indicate detrital variations governed by the fluvial dynamics in the region. This demands a more detail catchment to sink...

  15. New types of submarine groundwater discharge from a saliferous clay formation - the case of the Dead Sea

    Science.gov (United States)

    Siebert, Christian; Broder, Merkel; Thomas, Pohl; Yossi, Yechieli; Eldat, Hazan; Danny, Ionescu; Ulf, Mallast

    2017-04-01

    Along the coastline of the hyper-saline and dramatically dropping Dead Sea, fresh to highly saline groundwaters discharge abundantly from dry falling lakebed. During its history, the level and hence salinity of the lake strongly fluctuated, resulting in the deposition of an alternating sequence of clayey and chemical sediments (mainly halite, carbonates and sulfates), intercalated by thick beds of halite and of coarse clastics around wadi outlets, respectively. Due to the asymmetrical shape of the lake's basin, these strata are deposited unequally along the eastern and western flank, why only groundwaters coming from the west have to pass thick layers of these sediments on their way into the lake. On the base of trace elements (REE), element ratios, stable and radioisotopes and microbiological findings, the observed onshore and offshore springs revealed, freshwaters discharge from both Cretaceous limestone aquifers and efficiently dissolve the easily soluble halite and flush the interstitial brines from the saliferous clay formation, immediately after entering the sedimentary strata. Abundant microbial activity result in the widespread production of sulfuric acid, accelerating erosion of carbonates and sulfates. These processes result in a fast and striking karstification of the strata, enabling groundwaters to transcendent the fresh/saltwater interface trough open pipes. As results, submarine groundwater discharge (SGD) occurs randomly and in addition to terrestrial, submarine sinkholes develop very quickly too. Due to the variable maturity of the flow paths, salinity and chemical composition of SGD shows an extremely wide range, from potable water to TDS of >250 g/l. Submarine emerging groundwaters with salinities even higher then that of the Dead Sea and distinctly different chemical and isotopic composition form outlets, which are not known elsewhere and represent a novel and unique type of SGD, only observed in the Dead Sea yet.

  16. Characterizing subsurface hydraulic heterogeneity of alluvial fan using riverstage fluctuations

    Science.gov (United States)

    Wang, Yu-Li; Yeh, Tian-Chyi Jim; Wen, Jet-Chau; Huang, Shao-Yang; Zha, Yuanyuan; Tsai, Jui-Pin; Hao, Yonghong; Liang, Yue

    2017-04-01

    The objective of this study is to demonstrate the ability of riverstage tomography to estimate 2-D spatial distribution of hydraulic diffusivity (D) of Zhuoshui River alluvial fan, Taiwan, using groundwater level data from 65 wells and stream stage data from 5 gauging stations. In order to accomplish this objective, wavelet analysis is first conducted to investigate the temporal characteristics of groundwater level, precipitation, and stream stage. The results of the analysis show that variations of groundwater level and stream stage are highly correlated over seasonal and annual periods while that between precipitation is less significant. Subsequently, spatial cross-correlation between seasonal variations of groundwater level and riverstage data is analyzed. It is found that the correlation contour map reflects the pattern of sediment distribution of the fan. This finding is further substantiated by the cross-correlation analysis using both noisy and noise-free groundwater and riverstage data of a synthetic aquifer, where aquifer heterogeneity is known exactly. The ability of riverstage tomography is then tested with these synthetic data sets to estimate D distribution. Finally, the riverstage tomography is applied to the alluvial fan. The results of the application reveal that the apex and southeast of the alluvial fan are regions with relatively high D and the D values gradually decrease toward the shoreline of the fan. In addition, D at northern alluvial fan is slightly larger than that at southern. These findings are consistent with the geologic evolution of this alluvial fan.

  17. Fans of Columbine shooters Eric Harris and Dylan Klebold

    Directory of Open Access Journals (Sweden)

    Andrew Ryan Rico

    2015-09-01

    Full Text Available On April 20, 1999, Eric Harris and Dylan Klebold murdered 12 students and one teacher at Columbine High School in Littleton, Colorado, in what was then the deadliest school shooting in American history. Despite causing a national panic and serving as a flash point for larger narratives on bullying, gun control, and media violence, both boys have gained active online fans. These fandoms dedicated to the Columbine shooters are widely referred to as dark examples of Internet communities, while the fans are also frequently denigrated as unstable and violent outcasts. Such dark online fandoms are yet to permeate mainstream culture or to challenge the preexisting perception of these communities as breeding grounds for the next wave of school shooters. While studies have covered the types of fans and their myriad interests, the field remains focused on more conventional examples of fan communities. In an effort to challenge and expand the object of focus when we study fandom, this qualitative study examines Columbine fans and their activity in order to understand the dominant motives they appear to have for engaging with and around such controversial figures and then concludes by exploring how this community might help us reflect more broadly on our concept of fandom. Redeeming these fans as part of diverse and complex communities of social relevance can demonstrate how even a dark fandom such as that of these Columbine shooters provides valuable cultural insights and benefits the field of fan studies.

  18. Reactive control of subsonic axial fan noise in a duct.

    Science.gov (United States)

    Liu, Y; Choy, Y S; Huang, L; Cheng, L

    2014-10-01

    Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical.

  19. A submarine volcanic eruption leads to a novel microbial habitat.

    Science.gov (United States)

    Danovaro, Roberto; Canals, Miquel; Tangherlini, Michael; Dell'Anno, Antonio; Gambi, Cristina; Lastras, Galderic; Amblas, David; Sanchez-Vidal, Anna; Frigola, Jaime; Calafat, Antoni M; Pedrosa-Pàmies, Rut; Rivera, Jesus; Rayo, Xavier; Corinaldesi, Cinzia

    2017-04-24

    Submarine volcanic eruptions are major catastrophic events that allow investigation of the colonization mechanisms of newly formed seabed. We explored the seafloor after the eruption of the Tagoro submarine volcano off El Hierro Island, Canary Archipelago. Near the summit of the volcanic cone, at about 130 m depth, we found massive mats of long, white filaments that we named Venus's hair. Microscopic and molecular analyses revealed that these filaments are made of bacterial trichomes enveloped within a sheath and colonized by epibiotic bacteria. Metagenomic analyses of the filaments identified a new genus and species of the order Thiotrichales, Thiolava veneris. Venus's hair shows an unprecedented array of metabolic pathways, spanning from the exploitation of organic and inorganic carbon released by volcanic degassing to the uptake of sulfur and nitrogen compounds. This unique metabolic plasticity provides key competitive advantages for the colonization of the new habitat created by the submarine eruption. A specialized and highly diverse food web thrives on the complex three-dimensional habitat formed by these microorganisms, providing evidence that Venus's hair can drive the restart of biological systems after submarine volcanic eruptions.

  20. Does calving matter? Evidence for significant submarine melt

    Science.gov (United States)

    Bartholomaus, Timothy C.; Larsen, Christopher F.; O’Neel, Shad

    2013-01-01

    During the summer in the northeast Pacific Ocean, the Alaska Coastal Current sweeps water with temperatures in excess of 12 °C past the mouths of glacierized fjords and bays. The extent to which these warm waters affect the mass balance of Alaskan tidewater glaciers is uncertain. Here we report hydrographic measurements made within Icy Bay, Alaska, and calculate rates of submarine melt at Yahtse Glacier, a tidewater glacier terminating in Icy Bay. We find strongly stratified water properties consistent with estuarine circulation and evidence that warm Gulf of Alaska water reaches the head of 40 km-long Icy Bay, largely unaltered. A 10–20 m layer of cold, fresh, glacially-modified water overlies warm, saline water. The saline water is observed to reach up to 10.4 °C within 1.5 km of the terminus of Yahtse Glacier. By quantifying the heat and salt deficit within the glacially-modified water, we place bounds on the rate of submarine melt. The submarine melt rate is estimated at >9 m d−1, at least half the rate at which ice flows into the terminus region, and can plausibly account for all of the submarine terminus mass loss. Our measurements suggest that summer and fall subaerial calving is a direct response to thermal undercutting of the terminus, further demonstrating the critical role of the ocean in modulating tidewater glacier dynamics.

  1. Submarine Construction in Germany (U-Bootbau in Deutschland),

    Science.gov (United States)

    1983-04-25

    the IKL sister firm, Maschinenbau Gabler GmbH, also founded by Prof. Gabler, which, unlike IKL (involved solely in development), is a hardware...snorkels, radar masts, as well as wharf and dockside connections, for IKL and various submarine yards. Moreover, Maschinenbau Gabler is engaged in

  2. Dissolved Nutrients from Submarine Groundwater in Flic en Flac ...

    African Journals Online (AJOL)

    Abstract—The aim of this study was to investigate dissolved nutrients in a submarine groundwater discharge (SGD) in Flic en Flac lagoon on the west coast of the volcanic island of Mauritius. The SGD enters Flic en Flac lagoon through a thin blanket of unconsolidated sediment through a fracture system and is concentrated ...

  3. Dissolved Nutrients from Submarine Groundwater in Flic en Flac ...

    African Journals Online (AJOL)

    The aim of this study was to investigate dissolved nutrients in a submarine groundwater discharge (SGD) in Flic en Flac lagoon on the west coast of the volcanic island of Mauritius. The SGD enters Flic en Flac lagoon through a thin blanket of unconsolidated sediment through a fracture system and is concentrated along the ...

  4. Simulation of Wave-Plus-Current Scour beneath Submarine Pipelines

    DEFF Research Database (Denmark)

    Eltard-Larsen, Bjarke; Fuhrman, David R.; Sumer, B. Mutlu

    2016-01-01

    A fully coupled hydrodynamic and morphologic numerical model was utilized for the simulation of wave-plus-current scour beneath submarine pipelines. The model was based on incompressible Reynolds-averaged Navier–Stokes equations, coupled with k-ω turbulence closure, with additional bed and suspen...

  5. Sedimentary characteristics of samples collected from some submarine canyons

    NARCIS (Netherlands)

    Bouma, Arnold H.

    Oriented rectangular cores of 20.3 × 30.5 cm and 45.7 cm high have been collected in a number of submarine canyons off southern California (U.S.A.) and off the southern tip of Baja California (Mexico) for a detailed study of their sedimentary structures. By applying several methods, mainly X-ray

  6. 'Good Hunting': German submarine offensives and South African ...

    African Journals Online (AJOL)

    The first German submarine offensive in South African waters during 1942, Operation Eisbär, was aimed at striking a devastating blow to shipping off the South African coast. By the end of December 1942, an estimated 310 864 tons of shipping had been sunk through Operation Eisbär and the first U-cruiser operation alone.

  7. Cost Estimation Lessons Learned for Future Submarine Acquisition Programs

    Science.gov (United States)

    2010-02-17

    North Carolina and New Mexico 30 General Dynamics Electric Boat “U.S. Navy Awards General Dynamics $14 Billion Contract for Eight Virginia- Class...NAVSEA Program Executive officer, Submarines PMO 450, June 1995. “New SSN Program Life Cycle Cost Estimate.” Naval Center for Cost Analysis: GE-1300

  8. Tectonic Tilting and Reorganization of an Aluvial Fan to a Dendritic, Erosional River Network: the Example of the Ogallala Gravels

    Science.gov (United States)

    Willett, S.; McCoy, S. W.; Beeson, H. W.

    2016-12-01

    Deposition of the Mio-Pliocene Ogallala gravels in the foreland of the Rocky Mountains represents a great natural experiment in landscape evolution. Starting about 20 million years ago the flux of sediment shed off the Rocky Mountains increased, likely in response to dynamic uplift of the Rockies and tilting of the High Plains. This event shifted the high plains from a state of erosion to deposition. The flux of sediment formed huge alluvial megafans, burying the pre-existing river network and effectively "repaving" the western High Plains. Today we are witnessing the re-establishment of a new river network that is dissecting, capturing and eroding these sediment fans. By mapping the modern drainage basins and noting the channel gradient with respect to the normalized length parameter, χ, we identify two types of basins in the high plains. The remnants of the alluvial megafans are drained by long narrow basins with low normalized steepness and nearly no concavity, reflecting little incision since formation. In contrast, the fan remnants are surrounded by basins with a dendritic structure and efficient water and sediment routing, resulting in low values of chi and correspondingly low elevation. The boundary between these two basin types is commonly an erosional escarpment, demonstrating that the trellis basins are consuming the fan deposits by lateral divide migration and successive river capture. We present scaling arguments that show that lateral escarpment advance is nearly an order of magnitude faster than the upstream (knickpoint) propagation of channel entrenchment. This process of landscape evolution has important implications for water in the high plains. Deprived of an efficient channel network, fan surfaces remain uneroded, preserving the Ogallala sediments, and the poorly-drained, poorly integrated surface retains ephemeral water for wetland habitat and aquifer recharge, illustrating how the surface hydrology reflects landscape evolution on million year

  9. An ongoing large submarine landslide at the Japan trench

    Science.gov (United States)

    Nitta, S.; Kasaya, T.; Miura, S.; Kawamura, K.

    2013-12-01

    This paper deals with an active submarine landslide on a landward trench slope in the Japan trench. Studied area is located on the upper terrace ranging from 400 to 1200 m in water depth, off Sendai, northeast Japan. We have surveyed in detail the seabed topography using a multi narrow beam (hereafter MBES) and a subbottom profiler (hereafter SBP) during the cruise MR12-E02 of R/V Mirai. The survey lines were 12 lines in N-S, and 3 lines in E-W, and situated in the region from 141°45'E, 37°40'N to 142°33'E, 38°32'N. Moreover, we used multi-channel seismic profile by the cruise KR04-10 of R/V Kairei in the interpretation of the SBP results. In general, horseshoe-shaped depressions of about 100 km wide along the trench slope are arrayed along the Japan trench. It has thought that they were formed by large submarine landslides, but we could not understand critically the relationship between the depressions and the submarine landslides. Based on the survey results, we found signals of an active submarine landslide in the depression as follows. 1) We observed arcuate-shaped lineaments, which are sub-parallel to a horseshoe-shaped depression. The lineaments concentrate in the south region from 38°N at about 20 km wide. These lineaments are formed by deformation structures as anticlines, synclines and normal fault sense displacements. 2) Most of the synclines and anticlines are not buried to form the lineaments. 3) Normal faults cutting about 1 km deep are observed in a multi-channel seismic profile. The normal faults are located just below the arcuate-shaped lineaments, and are tilted eastward being the downslope direction. It indicates a large submarine landslide. We concluded that the arcuate-shaped lineaments were generated by surface sediment movement with the submarine landsliding. We think that the submarine landslide of about 20 km wide and about 1 km thick move continuously down the landward trench slope. This would be the formation process of the horseshoe

  10. Tectonic activity and the evolution of submarine canyons: The Cook Strait Canyon system, New Zealand

    Science.gov (United States)

    Micallef, Aaron; Mountjoy, Joshu; Barnes, Philip; Canals, Miquel; Lastras, Galderic

    2016-04-01

    Submarine canyons are Earth's most dramatic erosional features, comprising steep-walled valleys that originate in the continental shelf and slope. They play a key role in the evolution of continental margins by transferring sediments into deep water settings and are considered important biodiversity hotspots, pathways for nutrients and pollutants, and analogues of hydrocarbon reservoirs. Although comprising only one third of continental margins worldwide, active margins host more than half of global submarine canyons. We still lack of thorough understanding of the coupling between active tectonics and submarine canyon processes, which is necessary to improve the modelling of canyon evolution in active margins and derive tectonic information from canyon morphology. The objectives of this study are to: (i) understand how tectonic activity influences submarine canyon morphology, processes, and evolution in an active margin, and (2) formulate a generalised model of canyon development in response to tectonic forcing based on morphometric parameters. We fulfil these objectives by analysing high resolution geophysical data and imagery from Cook Strait Canyon system, offshore New Zealand. Using these data, we demonstrate that tectonic activity, in the form of major faults and structurally-generated tectonic ridges, leaves a clear topographic signature on submarine canyon location and morphology, in particular their dendritic and sinuous planform shapes, steep and linear longitudinal profiles, and cross-sectional asymmetry and width. We also report breaks/changes in canyon longitudinal slope gradient, relief and slope-area regression models at the intersection with faults. Tectonic activity gives rise to two types of knickpoints in the Cook Strait Canyon. The first type consists of low slope gradient, rounded and diffusive knickpoints forming as a result of short wavelength folds or fault break outs and being restored to an equilibrium profile by upstream erosion and

  11. Turbine Engine with Differential Gear Driven Fan and Compressor

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Pagluica, Gino J. (Inventor); Duong, Loc Quang (Inventor); Portlock, Lawrence E. (Inventor)

    2013-01-01

    A gas turbine engine provides a differential gear system coupling the turbine to the bypass fan and the compressor. In this manner, the power/speed split between the bypass fan and the compressor can be optimized under all conditions. In the example shown, the turbine drives a sun gear, which drives a planet carrier and a ring gear in a differential manner. One of the planet carrier and the ring gear is coupled to the bypass fan, while the other is coupled to the compressor.

  12. The Star Wars franchise, fan edits, and Lucasfilm [symposium

    Directory of Open Access Journals (Sweden)

    Forrest Phillips

    2012-03-01

    Full Text Available Fan edits assert that fan authority is on par with that of a work's original creator; this authority is generated not only through the argument, but through the structure of the text itself. Fan edits adhere to classical filmmaking techniques, creating coherent plots and editing for continuity. These recut texts are emblematic of current ownership debates; they are the read/write culture brought to fandom. The Star Wars series of films are among the most frequently recut texts and are my focus here.

  13. Performance Study and CFD Predictions of a Ducted Fan System

    Science.gov (United States)

    Abrego, Anita I.; Chang, I-Chung; Bulaga, Robert W.; Rutkowski, Michael (Technical Monitor)

    2002-01-01

    An experimental investigation was completed in the NASA Ames 7 by 10-Foot Wind Tunnel to study the performance characteristics of a ducted fan. The goal of this effort is to study the effect of ducted fan geometry and utilize Computational Fluid Dynamics (CFD) analysis to provide a baseline for correlation. A 38-inch diameter, 10-inch chord duct with a five-bladed fixed-pitch fan was tested. Duct performance data were obtained in hover, vertical climb, and forward flight test conditions. This paper will present a description of the test, duct performance results and correlation with CFD predictions.

  14. K-pop Reception and Participatory Fan Culture in Austria

    OpenAIRE

    Sang-Yeon Sung

    2013-01-01

    K-pop’s popularity and its participatory fan culture have expanded beyond Asia and become significant in Europe in the past few years. After South Korean pop singer Psy’s “Gangnam Style” music video topped the Austrian chart in October 2012, the number and size of K-pop events in Austria sharply increased, with fans organizing various participatory events, including K-pop auditions, dance festivals, club meetings, quiz competitions, dance workshops, and smaller fan-culture gatherings. In the ...

  15. Exploring the submarine Graham Bank in the Sicily Channel

    Directory of Open Access Journals (Sweden)

    Mauro Coltelli

    2016-05-01

    Full Text Available In the Sicily Channel, volcanic activity has been concentrated mainly on the Pantelleria and Linosa islands, while minor submarine volcanism took place in the Adventure, Graham and Nameless banks. The volcanic activity spanned mostly during Plio-Pleistocene, however, historical submarine eruptions occurred in 1831 on the Graham Bank and in 1891 offshore Pantelleria Island. On the Graham Bank, 25 miles SW of Sciacca, the 1831 eruption formed the short-lived Ferdinandea Island that represents the only Italian volcano active in historical times currently almost completely unknown and not yet monitored. Moreover, most of the Sicily Channel seismicity is concentrated along a broad NS belt extending from the Graham Bank to Lampedusa Island. In 2012, the Istituto Nazionale di Geofisica e Vulcanologia (INGV carried out a multidisciplinary oceanographic cruise, named “Ferdinandea 2012”, the preliminary results of which represent the aim of this paper. The cruise goal was the mapping of the morpho-structural features of some submarine volcanic centres located in the northwestern side of the Sicily Channel and the temporary recording of their seismic and degassing activity. During the cruise, three OBS/Hs (ocean bottom seismometer with hydrophone were deployed near the Graham, Nerita and Terribile submarine banks. During the following 9 months they have recorded several seismo-acoustic signals produced by both tectonic and volcanic sources. A high-resolution bathymetric survey was achieved on the Graham Bank and on the surrounding submarine volcanic centres. A widespread and voluminous gas bubbles emission was observed by both multibeam sonar echoes and a ROV (remotely operated vehicle along the NW side of the Graham Bank, where gas and seafloor samples were also collected.

  16. Shelf erosion and submarine river canyons: implications for deep-sea oxygenation and ocean productivity during glaciation

    Directory of Open Access Journals (Sweden)

    I. Tsandev

    2010-06-01

    Full Text Available The areal exposure of continental shelves during glacial sea level lowering enhanced the transfer of erodible reactive organic matter to the open ocean. Sea level fall also activated submarine canyons thereby allowing large rivers to deposit their particulate load, via gravity flows, directly in the deep-sea. Here, we analyze the effects of shelf erosion and particulate matter re-routing to the open ocean during interglacial to glacial transitions, using a coupled model of the marine phosphorus, organic carbon and oxygen cycles. The results indicate that shelf erosion and submarine canyon formation may significantly lower deep-sea oxygen levels, by up to 25%, during sea level low stands, mainly due to the supply of new material from the shelves, and to a lesser extent due to particulate organic matter bypassing the coastal zone. Our simulations imply that deep-sea oxygen levels can drop significantly if eroded shelf material is deposited to the seafloor. Thus the glacial ocean's oxygen content could have been significantly lower than during interglacial stages. Primary production, organic carbon burial and dissolved phosphorus inventories are all affected by the erosion and rerouting mechanisms. However, re-routing of the continental and eroded shelf material to the deep-sea has the effect of decoupling deep-sea oxygen demand from primary productivity in the open ocean. P burial is also not affected showing a disconnection between the biogeochemical cycles in the water column and the P burial record.

  17. Large-scale internal structure in volcanogenic breakout flood deposits: Extensive GPR survey on volcaniclastic deposits

    Science.gov (United States)

    Kataoka, K.; Gomez, C. A.

    2012-12-01

    Large-scale outburst floods from volcanic lakes such as caldera lakes or volcanically dammed river-valleys tend to be voluminous with total discharge of > 1-10s km3 and peak discharge of >10000s to 100000s m3 s-1. Such a large flood can travel long distance and leave sediments and bedforms/landforms extensively with large-scale internal structures, which are difficult to assess from single local sites. Moreover, the sediments and bedforms/landforms are sometimes untraceable, and outcrop information obtained by classical geological and geomorphological field surveys is limited to the dissected/terraced parts of fan body, road cuts and/or large quarries. Therefore, GPR (Ground Penetrating Radar), using the properties of electromagnetic waves' propagation through media, seems best adapted for the appraisal of large-scale subsurface structures. Recently, studies on GPR applications to volcanic deposits have successfully captured images of lava flows and volcaniclastic deposits and proved the usefulness of this method even onto the volcanic areas which often encompass complicated stratigraphy and structures with variable material, grainsize, and ferromagnetic content. Using GPR, the present study aims to understand the large-scale internal structures of volcanogenic flood deposits. The survey was carried out over two volcanogenic flood fan (or apron) sediments in northeast Japan, at Numazawa and Towada volcanoes. The 5 ka Numazawa flood deposits in the Tadami river catchment that has been emplaced by a breakout flood from ignimbrite-dammed valley leaving pumiceous gravelly sediments with meter-sized boulders in the flow path. At Towada volcano, a comparable flood event originating from a breach in the caldera rim emplaced the 13-15 ka Sanbongi fan deposits in the Oirase river valley, which is characterized by a bouldery fan deposits. The GPR data was collected following 200 to 500 m long lateral and longitudinal transects, which were captured using a GPR Pulse

  18. New Mapping of Mariana Submarine Volcanoes with Sidescan and Multibeam Sonars

    Science.gov (United States)

    Embley, R. W.; Chadwick, W. W.; Baker, E. T.; Johnson, P. D.; Merle, S. G.; Ristau, S.

    2003-12-01

    aprons of the islands and larger submarine volcanoes, sediment waves with wavelengths of up to 1.0 km and amplitudes up to 50 m commonly occur. Their crests are almost always oriented parallel to regional contours, indicating a formation mechanism related to down slope flow. In some places clear transitions occur between mass flows on the volcanoes' steeper flanks and the sediment waves on the gentler slopes of the apron. A preliminary interpretation is the sediment waves form during the transition from channelized to unconstrained flows. Sediment waves of similar scale are commonly observed on the levees of deep-sea channels and on deep-sea fans. The location and shape of the arc volcanoes are often controlled or influenced by tectonic control. Within the southern part of the Central Island Province, from about 15\\deg 50' N to 18\\deg 00' N, volcanoes often line up and/or are elongated in an E-W or an E-NE direction. There are several cross-chains of volcanoes in this region that penetrate 10's of kms into the back-arc basin. Along the northern part of the arc (the Northern Seamount Province), where the convergence direction is roughly parallel to the arc front, the structure is more complex. Several active volcanoes occur at the intersection of two or more structural lineaments northwest of Farallon de Pajaros Island. There are several volcanoes in the northern area that are narrow ridges striking in a S-SW trend 9 (arc-orthogonal).

  19. COOLING FAN AND SYSTEM PERFORMANCE AND EFFICIENCY IMPROVEMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Ronald Dupree

    2005-07-31

    Upcoming emissions regulations (Tiers 3, 4a and 4b) are imposing significantly higher heat loads on the cooling system than lesser regulated machines. This work was a suite of tasks aimed at reducing the parasitic losses of the cooling system, or improving the design process through six distinct tasks: 1. Develop an axial fan that will provide more airflow, with less input power and less noise. The initial plan was to use Genetic Algorithms to do an automated fan design, incorporating forward sweep for low noise. First and second generation concepts could not meet either performance or sound goals. An experienced turbomachinery designer, using a specialized CFD analysis program has taken over the design and has been able to demonstrate a 5% flow improvement (vs 10% goal) and 10% efficiency improvement (vs 10% goal) using blade twist only. 2. Fan shroud developments, using an 'aeroshroud' concept developed at Michigan State University. Performance testing at Michigan State University showed the design is capable of meeting the goal of a 10% increase in flow, but over a very narrow operating range of fan performance. The goal of 10% increase in fan efficiency was not met. Fan noise was reduced from 0 to 2dB, vs. a goal of 5dB at constant airflow. The narrow range of fan operating conditions affected by the aeroshroud makes this concept unattractive for further development at this time 3. Improved axial fan system modeling is needed to accommodate the numbers of cooling systems to be redesigned to meet lower emissions requirements. A CFD fan system modeling guide has been completed and transferred to design engineers. Current, uncontrolled modeling practices produce flow estimates in some cases within 5% of measured values, and in some cases within 25% of measured values. The techniques in the modeling guide reduced variability to the goal of + 5% for the case under study. 4. Demonstrate the performance and design versatility of a high performance fan. A

  20. Representation of American versus non-American fans in Baillie Walsh's Springsteen & I

    NARCIS (Netherlands)

    Wilkinson, M.C.

    2015-01-01

    This article explores the representation of American versus non-American fans in Baillie Walsh's 2013 crowd/fan-sourced documentary Springsteen & I. The film—as much as it was fed by a wide and international range of fan-produced material—ultimately produced and presented one particular type of fan

  1. 14 CFR 33.27 - Turbine, compressor, fan, and turbosupercharger rotors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine, compressor, fan, and... Turbine, compressor, fan, and turbosupercharger rotors. (a) Turbine, compressor, fan, and... affect turbine, compressor, fan, and turbosupercharger rotor structural integrity will not be exceeded in...

  2. Life, death and revival of debris-flow fans on Earth and Mars : fan dynamics and climatic inferences

    OpenAIRE

    de Haas, T.

    2016-01-01

    Alluvial fans are ubiquitous landforms in high-relief regions on Earth and Mars. They have a semi-conical shape and are located at the transition between highlands and adjacent basins. Alluvial fans can form by a range of processes including debris flows, which are water-laden masses of soil and rock with volumetric sediment concentrations exceeding 40%. In this thesis, I aim to (1) unravel the formative dynamics of debris-flow fans and, building on these insights, to (2) reconstruct hydrolog...

  3. Versions of Homer: Translation, fan fiction, and other transformative rewriting

    Directory of Open Access Journals (Sweden)

    Shannon K. Farley

    2016-03-01

    Full Text Available This article posits a paradigm of transformative work that includes translation, adaptation, and fan fiction using the Homeric epics as a case study. A chronological discussion of translations, other literary rewritings, and fan fiction distinguishes each as belonging to its respective cultural system while participating in a common form of transformative rewriting. Such a close look at the distinctive ways that Homer has been rewritten throughout history helps us to make a scholarly distinction between the work of fan writers and the work of rewriters like Vergil and Alexander Pope. At the same time, discussing the ways in which the forms of their rewritings are similar gives a scholarly basis for arguing that fan fiction participates in the discourse of serious interpretive literature.

  4. Pathological effects of cyanobacteria on sea fans in southeast Florida.

    Science.gov (United States)

    Kiryu, Y; Landsberg, J H; Peters, E C; Tichenor, E; Burleson, C; Perry, N

    2015-07-01

    In early August 2008, observations by divers indicated that sea fans, particularly Gorgonia ventalina, Gorgonia flabellum, and Iciligorgia schrammi, were being covered by benthic filamentous cyanobacteria. From August 2008 through January 2009 and again in April 2009, tissue samples from a targeted G. ventalina colony affected by cyanobacteria and from a nearby, apparently healthy (without cyanobacteria) control colony, were collected monthly for histopathological examination. The primary cellular response of the sea fan to overgrowth by cyanobacteria was an increase in the number of acidophilic amoebocytes (with their granular contents dispersed) that were scattered throughout the coenenchyme tissue. Necrosis of scleroblasts and zooxanthellae and infiltration of degranulated amoebocytes were observed in the sea fan surface tissues at sites overgrown with cyanobacteria. Fungal hyphae in the axial skeleton were qualitatively more prominent in cyanobacteria-affected sea fans than in controls. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Low Cost/Low Noise Variable Pitch Ducted Fan Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ACI proposes a design for a Propulsor (Low Cost/Low Noise Variable Pitch Ducted Fan) that has wide application in all sectors of Aviation. Propulsor hardware of this...

  6. Foil Gas Bearing Supported Quiet Fan for Spacecraft Ventilation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Developing a quiet fan for Environmental Control and Life Support systems to enhance the livable environment within the spacecraft has been a challenge. A Foil Gas...

  7. Autonomous Composite Fan Containment Integrity Monitoring (AUTOCONFIRM) System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New engine fan blade containment structures are being manufactured with advanced composite structures such that they can withstand blade-out events. The use of...

  8. Neural bases of ingroup altruistic motivation in soccer fans

    National Research Council Canada - National Science Library

    Tiago Bortolini; Patrícia Bado; Sebastian Hoefle; Annerose Engel; Roland Zahn; Ricardo de Oliveira Souza; Jean-Claude Dreher; Jorge Moll

    2017-01-01

    .... Here, we used soccer fandom as an ecological framing of group membership to investigate the neural mechanisms underlying ingroup altruistic behaviour in male fans using event-related functional magnetic resonance...

  9. "The florals": Female fans over 50 in the Sherlock fandom

    National Research Council Canada - National Science Library

    Line Nybro Petersen

    2017-01-01

    ...–). The research aims to better understand the role of fandom in later life, in particular how the participants in this study negotiate their perceptions of their subjective age in relation to being a fan...

  10. New Directions in Music Fan Studies Editorial Introduction

    NARCIS (Netherlands)

    dr. Koos Zwaan

    Introduction to a special issue of the IASPM journal. This special issue on fan studies aims to build a bridge with the study of popular music in order to inspire further investigation of music fandom.

  11. The Female Vikings, a women's fan group in Denmark

    DEFF Research Database (Denmark)

    Mintert, Svenja-Maria; Pfister, Gertrud Ursula

    2014-01-01

    Traditionally, football and fandom have been male domains and celebrations of masculinity. So far there has been some sociological and historical research on women's football; however, little is known about women's fandom, in particular about its formation and development. This article focuses...... on the historical development of a Danish women-only fan group called 'The Female Vikings', which support a professional football club, Lyngby Boldklub (BK), in a city north of Copenhagen. The article explores the backgrounds and motivations of female fans, as well as their ways of staging femininity in a man......'s world. Drawing on available information about football and fans in Denmark, we have reconstructed the developments of both Lyngby BK and its supporters. Special focus was placed on the histories and cultures as well as the experiences of female fans in this club. Insights into the foundation...

  12. Construction of violence in football: psychologization of the fan

    National Research Council Canada - National Science Library

    Juan Carlos Arboleda-Ariza; Margarita Maria Velez Maya

    2016-01-01

    .... We found that the press places the "fan" as a central axis when referring to the phenomenon of football violence, appealing to the psychologization and criminalization of this to explain the violence...

  13. Cycling on rollers: Kreitler fan resistance at submaximal levels of effort.

    Science.gov (United States)

    Reiser, R F; Hart, C R

    2008-03-01

    The goal of this investigation was to characterize the commercially available fan unit for the KreitlerAlloy rollers at submaximal levels of effort (cyclist rode six times at each of three fan inlet settings (closed, half, and full open) and five fan speeds (900, 1800, 2700, 3600, and 4500 rpm). Fan power requirements were isolated by subtracting roller resistance from separate trials. Power requirements relative to fan inlet and fan speed possessed a significant interaction with the main effects for each also significant (all p or = 0.997). Fan resistance was virtually non existent at 900 rpm. Fan resistance then significantly increased with increasing fan speed and inlet opening. At 4500 rpm power requirements of the fan reached 269 +/- 6, 352 +/- 7, and 406 +/- 9 W with the inlet closed, half, and fully open, respectively (p training and testing environments.

  14. Space-for-time substitution and the evolution of submarine canyons in a passive, progradational margin.

    Science.gov (United States)

    Micallef, Aaron; Ribó, Marta; Canals, Miquel; Puig, Pere; Lastras, Galderic; Tubau, Xavier

    2013-04-01

    40% of submarine canyons worldwide are located in passive margins, where they constitute preferential conduits of sediment and biodiversity hotspots. Recent studies have presented evidence that submarine canyons incising passive, progradational margins can co-evolve with the adjacent continental slope during long-term margin construction. The stages of submarine canyon initiation and their development into a mature canyon-channel system are still poorly constrained, however, which is problematic when attempting to reconstruct the development of passive continental margins. In this study we analyse multibeam echosounder and seismic reflection data from the southern Ebro margin (western Mediterranean Sea) to document the stages through which a first-order gully develops into a mature, shelf-breaching canyon and, finally, into a canyon-channel system. This morphological evolution allows the application of a space-for-time substitution approach. Initial gully growth on the continental slope takes place via incision and downslope elongation, with limited upslope head retreat. Gravity flows are the main driver of canyon evolution, whereas slope failures are the main agent of erosion; they control the extent of valley widening, promote tributary development, and their influence becomes more significant with time. Breaching of the continental shelf by a canyon results in higher water/sediment loads that enhance canyon development, particularly in the upper reaches. Connection of the canyon head with a paleo-river changes evolution dynamics significantly, promoting development of a channel and formation of depositional landforms. Morphometric analyses demonstrate that canyons develop into geometrically self-similar systems that approach steady-state and higher drainage efficiency. Canyon activity in the southern Ebro margin is pulsating and enhanced during sea level lowstands. Rapid sedimentation by extension of the palaeo-Millars River into the outermost shelf and upper

  15. Internal tides affect benthic community structure in an energetic submarine canyon off SW Taiwan

    Science.gov (United States)

    Liao, Jian-Xiang; Chen, Guan-Ming; Chiou, Ming-Da; Jan, Sen; Wei, Chih-Lin

    2017-07-01

    Submarine canyons are major conduits of terrestrial and shelf organic matter, potentially benefiting the seafloor communities in the food-deprived deep sea; however, strong bottom currents driven by internal tides and the potentially frequent turbidity currents triggered by storm surges, river flooding, and earthquakes may negatively impact the benthos. In this study, we investigated the upper Gaoping Submarine Canyon (GPSC), a high-sediment-yield canyon connected to a small mountain river (SMR) off southwest (SW) Taiwan. By contrasting the benthic meiofaunal and macrofaunal communities within and outside the GPSC, we examined how food supplies and disturbance influenced the benthic community assemblages. The benthic communities in the upper GPSC were mainly a nested subset of the adjacent slope assemblages. Several meiofaunal (e.g. ostracods) and macrofaunal taxa (e.g. peracarid crustaceans and mollusks) that typically occurred on the slope were lost from the canyon. The polychaete families switched from diverse feeding guilds on the slope to motile subsurface deposit feeders dominant in the canyon. The diminishing of epibenthic peracarids and proliferation of deep burrowing polychaetes in the GPSC resulted in macrofauna occurring largely within deeper sediment horizons in the canyon than on the slope. The densities and numbers of taxa were depressed with distinct and more variable composition in the canyon than on the adjacent slope. Both the densities and numbers of taxa were negatively influenced by internal tide flushing and positively influenced by food availability; however, the internal tides also negatively influenced the food supplies. While the meiofauna and macrofauna densities were both depressed by the extreme physical conditions in the GPSC, only the macrofaunal densities increased with depth in the canyon, presumably related to increased frequency and intensity of disturbance toward the canyon head. The population densities of meiofauna, on the

  16. On the Optimal Selection of Electrical Machines Fans

    Directory of Open Access Journals (Sweden)

    Mădălin Costin

    2014-09-01

    Full Text Available In this paper an analytic relationship for electrical machine fan design has been developed. In the particularly case of salient poles synchronous machine (with salient poles – for electromagnetic field excitation or surface mounded permanent magnet, this approach allowed to express the fan power as a function of machine middle axe air gap. This analytic foundation developed may leads to different optimization criteria as specific active materials or costs. Numerical simulations confirm our approach.

  17. Potential Global Benefits of Improved Ceiling Fan Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Sathaye, Nakul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Letschert, Virginie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-10-31

    Ceiling fans contribute significantly to residential electricity consumption, both in an absolute sense and as a proportion of household consumption in many locations, especially in developing countries in warm climates. However, there has been little detailed assessment of the costs and benefits of efficiency improvement options for ceiling fans and the potential resulting electricity consumption and greenhouse gas (GHG) emissions reductions. We analyze the costs and benefits of several options to improve the efficiency of ceiling fans and assess the global potential for electricity savings and GHG emission reductions with more detailed assessments for India, China, and the U.S. We find that ceiling fan efficiency can be cost-effectively improved by at least 50% using commercially available technology. If these efficiency improvements are implemented in all ceiling fans sold by 2020, 70 terrawatt hours per year (TWh/year) could be saved and 25 million metric tons of carbon dioxide (CO2) emissions per year could be avoided, globally. We assess how policies and programs such as standards, labels, and financial incentives can be used to accelerate the adoption of efficient ceiling fans in order to realize this savings potential.

  18. Subsurface temperature distribution in a tropical alluvial fan

    Science.gov (United States)

    Chen, Wenfu; Chang, Minhsiang; Chen, Juier; Lu, Wanchung; Huang, Chihc; Wang, Yunshuen

    2017-04-01

    As a groundwater intensive use country, Taiwan's 1/3 water supplies are derived from groundwater. The major aquifers consist of sand and gravel formed in alluvial fans which border the fronts of central mountains. Thanks to high density of monitoring wells which provide a window to see the details of the subsurface temperature distribution and the thermal regime in an alluvial fan system. Our study area, the Choshui Alluvial Fan, is the largest groundwater basin in Taiwan and, located within an area of 2,000 km2, has a population of over 1.5 million. For this work, we investigated temperature-depth profiles using 70 groundwater monitoring wells during 2000 to 2015. Our results show that the distribution of subsurface temperature is influenced by various factors such as groundwater recharge, groundwater flow field, air temperature and land use. The groundwater recharge zone, hills to the upper fan, contains disturbed and smaller geothermal gradients. The lack of clay layers within the upper fan aquifers and fractures that developed in the hills should cause the convection and mixing of cooler recharge water to groundwater, resulting in smaller geothermal gradients. The groundwater temperatures at a depth to 300 m within the upper fan and hill were approximately only 23-24 °C while the current mean ground surface temperature is approximately 26 °C.

  19. "The florals": Female fans over 50 in the Sherlock fandom

    Directory of Open Access Journals (Sweden)

    Line Nybro Petersen

    2017-03-01

    Full Text Available This article uses e-mail interviews with nine female fans to explore what it means to be a fan over the age of 50 of the popular BBC drama Sherlock (2010–. The research aims to better understand the role of fandom in later life, in particular how the participants in this study negotiate their perceptions of their subjective age in relation to being a fan in this part of their life course. This study combines theory on cultural gerontology with fan studies and mediatization theory in order to understand the dynamics and processes that guide fans' negotiations of subjective age as well as the role of fan practices and the affordances of social media in these processes. I argue that fandom, as a manifestation of a mediatized culture, augments the relevance of subjective age and informs the way in which participants in middle and later life perceive and negotiate their own subjective age specifically in relation to fandom as youth culture, women's passion, and creativity.

  20. Fan activism, cybervigilantism, and Othering mechanisms in K-pop fandom

    OpenAIRE

    Sun Jung

    2012-01-01

    Korean popular music (K-pop) fandom may serve as a case study to identify both cynical and utopian views of fans' participatory Net activism by addressing three key aspects: fan activism, cybervigilantism, and Othering mechanisms. Fancom (fan company) in the K-pop scene refers to the way fans systematically manage their own stars. These notions of assertive fancom practices address how fans actively participate in sociocultural events such as fund raising, donating to charity, and volunteerin...

  1. Erosion dynamics modelling in a coupled catchment-fan system with constant external forcing

    OpenAIRE

    Pepin, E.; Carretier, Sébastien; Hérail, Gérard

    2010-01-01

    Recent alluvial fan models have suggested that deep alluvial fan entrenchment could occur without any change in sediment and water influx. Moreover, other studies have shown that the evolution of a fan could strongly depend on feedback between the fan and the mountain catchment. We evaluate if natural entrenchment still occurs in a coupled catchment-fan system, and we evaluate its possible impact on the evolution of mountain erosion. We use a landscape evolution model where the mountain corre...

  2. Review: Bettina Fritzsche (2003. Pop-Fans. Studie einer Mädchenkultur [Pop-Fans: Study of a Girl Culture

    Directory of Open Access Journals (Sweden)

    Lothar Mikos

    2006-05-01

    Full Text Available This study focuses on the "girl culture" created by fans of boy groups and girl groups. The central case study is used to examine fan practices as cultural practices using reconstructive and documentary methodologies, and to assess the normative demands placed on young people. The study centers on the question of gender socialization by mediated symbolic resources, and shows that fan culture is a self-determined space in which girls can negotiate normative demands and engage with questions of gender, sexuality and the body, testing conformity and obstinacy. Fan activities are presented as part of the self-empowerment of girls. The study makes an important contribution to the research of a specific girl culture. It shows in a brilliant way how media representations are used as symbolic material in everyday cultural practices. URN: urn:nbn:de:0114-fqs0603187

  3. Submarine landslides in contourite drifts along the Pianosa Ridge (Northern Tyrrhenian Sea): A geotechnical approach.

    Science.gov (United States)

    Miramontes Garcia, Elda; Sultan, Nabil; Garziglia, Sebastien; Jouet, Gwenael; Cauquil, Eric; Cattaneo, Antonio

    2016-04-01

    The Pianosa Ridge is a tectonic structure in the Northern Tyrrhenian Sea that forms the eastern flank of the Corsica trough (between Corsica and the Tuscan shelf). It is characterised by the presence of submarine landslides within the Pianosa Contourite Depositional System. Multibeam bathymetry, High-Resolution-72 channel (50-250 Hz) and CHIRP (3200-5200 Hz) seismic reflection profiles, collected during cruises PRISME2 and PRISME3 in 2013, revealed that bottom currents created a heterogeneous sedimentation pattern, resulting in zones of preferential deposition (drifts) and zones of erosion and/or non-deposition (moat and abraded surfaces). The sector where the largest submarine landslides took place is characterised by the presence of a plastered drift, a sediment body with a maximum thickness in the mid-low continental slope and a moat at the toe of the slope. Calypso piston cores and piezocone CPTu data acquired during the PRISME3 cruise in 2013 also provide valuable information about the lithology, geomechanical properties and stress history of contourite drifts and of the shallowest submarine landslide, named Pianosa Slump. Contourites in this area are mostly muddy, with coarser layers deposited during sea level falls. During sea level low-stands sedimentation rates (up to 115 cm•kyr-1 in the plastered drift) are higher than during sea level high-stands (20 cm•kyr-1 in the plastered drift). The plastered drift is underconsolidated with Overconsolidation Ratios (OCR) that range between 0.5 and 0.8. The Pianosa Slump formed in the plastered drift at 43-50 kyr BP has a volume of 2.62 km3, and it is covered by 17-20 m of sediment. The basal shear surface of the Pianosa Slump, at 30-56 m below the present-day seafloor, is correlated with a sediment layer characterised by the presence of zeolite minerals (up to 4% of sediment volume), high water content, low density, high compressibility, high permeability, high undrained shear strength and a post-peak strain

  4. Authigenic Carbonate Fans from Lower Jurassic Marine Shales (Alberta, Canada)

    Science.gov (United States)

    Martindale, R. C.; Them, T. R., II; Gill, B. C.; Knoll, A. H.

    2016-12-01

    Authigenic aragonite seafloor fans are a common occurrence in Archean and Paleoproterozoic carbonates, as well as Neoproterozoic cap carbonates. Similar carbonate fans are rare in Phanerozoic strata, with the exception of two mass extinction events; during the Permo-Triassic and Triassic-Jurassic boundaries, carbonate fans formed at the sediment-water interface and within the sediment, respectively. These crystal fans have been linked to carbon cycle perturbations at the end of the Permian and Triassic periods driven by rapid flood volcanism. The Early Jurassic Toarcian Ocean Anoxic Event (T-OAE) is also correlated with the emplacement of a large igneous province, but biological consequences were more modest. We have identified broadly comparable fibrous calcite layers (2-10 cm thick) in Pliensbachian-Toarcian cores from Alberta, Canada. This work focuses on the geochemical and petrographic description of these fans and surrounding sediment in the context of the T-OAE. At the macroscale, carbonates exhibit a fan-like (occasionally cone-in-cone) structure and displace the sediment around them as they grew. At the microscale, the carbonate crystals (pseudomorphs of aragonite) often initiate on condensed horizons or shells. Although they grow in multiple directions (growth within the sediment), the predominant crystal growth direction is towards the sediment-water interface. Resedimentation of broken fans is evidence that crystal growth was penecontemporaneous with sedimentation. The carbon isotope composition of the fans (transects up bladed crystals) and elemental abundances within the layers support shallow subsurface, microbially mediated growth. The resemblance of these Early Jurassic fibrous calcite layers to those found at the end-Triassic and their paucity in the Phanerozoic record suggest that analogous processes occurred at both events. Nevertheless, the Pliensbachian-Toarcian carbonate fans occur at multiple horizons and while some are within the T

  5. Genes2FANs: connecting genes through functional association networks

    Directory of Open Access Journals (Sweden)

    Dannenfelser Ruth

    2012-07-01

    Full Text Available Abstract Background Protein-protein, cell signaling, metabolic, and transcriptional interaction networks are useful for identifying connections between lists of experimentally identified genes/proteins. However, besides physical or co-expression interactions there are many ways in which pairs of genes, or their protein products, can be associated. By systematically incorporating knowledge on shared properties of genes from diverse sources to build functional association networks (FANs, researchers may be able to identify additional functional interactions between groups of genes that are not readily apparent. Results Genes2FANs is a web based tool and a database that utilizes 14 carefully constructed FANs and a large-scale protein-protein interaction (PPI network to build subnetworks that connect lists of human and mouse genes. The FANs are created from mammalian gene set libraries where mouse genes are converted to their human orthologs. The tool takes as input a list of human or mouse Entrez gene symbols to produce a subnetwork and a ranked list of intermediate genes that are used to connect the query input list. In addition, users can enter any PubMed search term and then the system automatically converts the returned results to gene lists using GeneRIF. This gene list is then used as input to generate a subnetwork from the user’s PubMed query. As a case study, we applied Genes2FANs to connect disease genes from 90 well-studied disorders. We find an inverse correlation between the counts of links connecting disease genes through PPI and links connecting diseases genes through FANs, separating diseases into two categories. Conclusions Genes2FANs is a useful tool for interpreting the relationships between gene/protein lists in the context of their various functions and networks. Combining functional association interactions with physical PPIs can be useful for revealing new biology and help form hypotheses for further experimentation. Our

  6. [Medical-physiological characteristics of combat training of nuclear-power submarine crews].

    Science.gov (United States)

    Dovgusha, V V; Myznikov, I L; Shalabodov, S A; Bumaĭ, O K

    2009-10-01

    The article presents an observe of general questions of peculiarities of military-professional activity of submarine staff These questions are defining value in ideology of medical supply of submarine troops of NAVY in now-days conditions. The article also presents the statistics of morbidity in long termed sails for last forty years, it's dynamics by different categories of sail staff, on different stages of combat training activity in dependence of perioditation of work cycle of submarine staff The authors have examined modern condition of medical supply of submarines; have presented statistics of quality indexes of health of submarine staff The authors have formed main problems of medical supply of submarines and have proposed ways of their solving on modern stage.

  7. Size Constraints on Late Miocene to Pliocene Submarine Slope Failures along the Colombian Caribbean Subduction Margin as a Basis for Assessing Circum-Caribbean Impact of Future Tsunami Events

    Science.gov (United States)

    Leslie, S.; Mann, P.

    2015-12-01

    The Colombian Caribbean margin provides an ideal setting for the formation of large mass transport deposits (MTDs): 1) the Caribbean Plate is slowly subducting at rates of 20 mm/yr with infrequent large thrust earthquakes and a complete lack of subduction events in the 400-year-long historical record; 2) the margin is a broad zone of active faults including a ~50 km-wide accretionary prism and strike-slip faults landward of the prism; 3) the active margin is draped by the Magdalena delta and submarine fan fed by the Magdalena River, the 26th largest in the world; and 4) the margin is over-steepened to slopes of up to 7° from the combination of tectonic activity and rapid rates of deltaic progradation. Using seismic data we have identified three late Miocene-Pliocene MTDs, the largest of which is between 4500 and 6000 km3, comparable in size to the well-studied Storegga slide of Norway. The tsunamigenic potential of future, analog MTD events are modeled using GeoWave tsunami modeling software. The largest and youngest of these MTDs, the Santa Marta slide, is used as an analog to infer the location and input parameters for the tsunami model. The event is modeled as a translational slide ~46 km long and ~37 km wide with the center of the slide located ~57 km W/NW from the mouth of the present day Magdalena River in water depths of 1500 m. The volume for the initial failure is conservatively estimated at ~680 km3 of material. The resulting tsunami wave from such an event has an initial maximum trough amplitude of -65.8 m and a peak amplitude of 19.2 m. The impact of such a tsunami would include: 1) Kingston, Jamaica (population 938K), tsunami height 7.5 m, peak arrival at 60 min.; 2) Santo Domingo, Dominican Republic (population 965K, height 6 m, peak arrival at 80 min.); and 3) Cartagena, Colombia (population 845K, height 21 m, peak arrival at 34 min.). A number of parameters to the model are varied to analyze sensitivity of modeling results to changes in slide depth

  8. Losses in armoured three-phase submarine cables

    DEFF Research Database (Denmark)

    Ebdrup, Thomas; Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2014-01-01

    increases the losses in armoured cables compared to unarmoured cables. In this paper a thorough state of the art analysis is conducted on armour losses in three-phase armoured submarine power cables. The analysis shows that the IEC 60287-1-1 standard overestimates the armour losses which lead...... to the installation of cables with excessive phase conductor cross section. This paper also presents an example of the potential economic benefits of having a better knowledge of the losses introduced by the armour.......The number of offshore wind farms will keep increasing in the future as a part of the shift towards a CO2 free energy production. The energy harvested from the wind farm must be brought to shore, which is often done by using a three-phase armoured submarine power cable. The use of an armour...

  9. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.

    1984-01-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, to obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular the dynamic pore pressure and the combined static and dynamic effective stresses are presented. 10 references, 11 figures.

  10. Stresses in a submarine topography under ocean waves

    Energy Technology Data Exchange (ETDEWEB)

    Mei, C.C.; McTigue, D.F.

    1984-09-01

    The problem of submarine slope stability is of interest to both offshore engineering and geology. In an uneven topography, the weight above a horizontal plane induces two-dimensional variation in the static stress field. The action of wave pressure, which changes with depth, further introduces excess pore pressure and dynamic stresses in the sea bottom. In the present paper, we combine a simple analytical theory for the static stress by the present authors, and the recent solution by Mei and Foda for wave-induced stresses in a plane poro-elastic sea bed to account for mild bottom slope and wave shoaling, and obtain the effective stress field in a submarine topography under sea waves. Sample results are given for a ridge and a canyon. In particular, the dynamic pore pressure and the combined static and dynamic effective stresses are presented.

  11. Sediment community responses to marine vs. terrigenous organic matter in a submarine canyon

    Directory of Open Access Journals (Sweden)

    W. R. Hunter

    2013-01-01

    Full Text Available The Whittard Canyon is a branching submarine canyon on the Celtic continental margin, which may act as a conduit for sediment and organic matter (OM transport from the European continental slope to the abyssal sea floor. In situ stable-isotope labelling experiments were conducted in the eastern and western branches of the Whittard Canyon, testing short-term (3–7 days responses of sediment communities to deposition of nitrogen-rich marine (Thalassiosira weissflogii and nitrogen-poor terrigenous (Triticum aestivum phytodetritus. 13C and 15N labels were traced into faunal biomass and bulk sediments, and the 13C label traced into bacterial polar lipid fatty acids (PLFAs. Isotopic labels penetrated to 5 cm sediment depth, with no differences between stations or experimental treatments (substrate or time. Macrofaunal assemblage structure differed between the eastern and western canyon branches. Following deposition of marine phytodetritus, no changes in macrofaunal feeding activity were observed between the eastern and western branches, with little change between 3 and 7 days. Macrofaunal C and N uptake was substantially lower following deposition of terrigenous phytodetritus with feeding activity governed by a strong N demand. Bacterial C uptake was greatest in the western branch of the Whittard Canyon, but feeding activity decreased between 3 and 7 days. Bacterial processing of marine and terrigenous OM were similar to the macrofauna in surficial (0–1 cm sediments. However, in deeper sediments bacteria utilised greater proportions of terrigenous OM. Bacterial biomass decreased following phytodetritus deposition and was negatively correlated to macrofaunal feeding activity. Consequently, this study suggests that macrofaunal–bacterial interactions influence benthic C cycling in the Whittard Canyon, resulting in differential fates for marine and terrigenous OM.

  12. Submarine landslide identified in DLW3102 core of the northern continental slope, South China Sea

    Science.gov (United States)

    Xu, Yuanqin; Liu, Lejun; Zhou, Hang; Huang, Baoqi; Li, Ping; Ma, Xiudong; Dong, Feiyin

    2018-02-01

    In this paper, we take DLW3101 core obtained at the top of the canyon (no landslide area) and DLW3102 core obtained at the bottom of the canyon (landslide area) on the northern continental slope of the South China Sea as research objects. The chronostratigraphic framework of the DLW3101 core and elemental strata of the DLW3101 core and the DLW3102 core since MIS5 are established by analyzing oxygen isotope, calcium carbonate content, and X-Ray Fluorescence (XRF) scanning elements. On the basis of the information obtained by analyzing the sedimentary structure and chemical elements in the landslide deposition, we found that the DLW3102 core shows four layers of submarine landslides, and each landslide layer is characterized by high Si, K, Ti, and Fe contents, thereby indicating terrigenous clastic sources. L1 (2.15-2.44 m) occurred in MIS2, which is a slump sedimentary layer with a small sliding distance and scale. L2 (15.48-16.00 m) occurred in MIS5 and is a debris flow-deposited layer with a scale and sliding distance that are greater than those of L1. L3 (19.00-20.90 m) occurred in MIS5; its upper part (19.00-20.00 m) is a debris flow-deposited layer, and its lower part (20.00-20.90 m) is a sliding deposition layer. The landslide scale of L3 is large. L4 (22.93-24.27 m) occurred in MIS5; its upper part (22.93-23.50 m) is a turbid sedimentary layer, and its lower part (23.50-24.27 m) is a slump sedimentary layer. The landslide scale of L4 is large.

  13. Franciscan olistoliths in Upper Cretaceous conglomerate deposits, Western Transverse Ranges, California: Implications for basin morphology and tectonic history

    Energy Technology Data Exchange (ETDEWEB)

    Reed, W.E.; Campbell, M.D. (Univ. of California, Los Angeles, CA (United States). Dept. of Earth and Space Sciences)

    1993-04-01

    Compositional analyses reveal that Upper Cretaceous sediments exposed in the Western Transverse Ranges of CA were deposited in submarine fan systems in a forearc basin. Point count data suggest a magmatic arc/recycled orogen as the dominant provenance for these sediments. Paleocurrent measurements from conglomerates in these sediments yield a northerly transport direction. Removal of ca. 90[degree] of clockwise rotation and 70 km of right-lateral slip restore this section to a position west of the San Diego area. The forearc basin would have had a N-S orientation, with the bulk of sediments supplied by the Peninsular Ranges to the east. Evidence of the erosion of the accretionary wedge is provided by the presence of large, internally stratified olistoliths of Franciscan material interbedded with and surrounded by upper Cretaceous conglomerate. Petrographic, quantitative SEM, and microprobe analyses indicate the presence of diagnostic Franciscan mineralogy, including glaucophane, riebeckite, lawsonite, and serpentine. Olistoclasts of chert, jadeitic graywacke, serpentine, and blueschist are found intermixed with the conglomerates in close association with the olistoliths. This association provides strong field evidence that recirculation of melange material within the subduction zone was active and well-established by late Cretaceous time. Inferences regarding the forearc system morphology can be drawn from these observations. The occurrence of coarse, easterly-derived conglomerates surrounded by large, stratified, but sheared, westerly-derived Franciscan debris, suggests a narrow, relatively steep-sided basin. Paleocurrent measurements gave no indication of axial transport within the basin. This morphology suggests that, in late Cretaceous time, the forearc basin was youthful, with a narrow arc-trench gap. Thus, relative convergence rates between the North American and Pacific plates were possibly slower than Tertiary convergence rates.

  14. Temporal variations of groundwater tables and implications for submarine groundwater discharge: a 3-decade case study in central Japan

    Directory of Open Access Journals (Sweden)

    B. Zhang

    2017-07-01

    Full Text Available Fresh submarine groundwater discharge (SGD is the key pathway of flux and nutrients for the groundwater from land to the ocean. SGD flux is a current issue of discussion and a means to clarify the coastal marine system under climate change. SGD flux accounts for about one-quarter of the river runoff in the Katakai alluvial fan in Uozu, Toyama, Japan, which is an ideal area to study SGD flux considering the need for a rapid response to climate change and the prior research on SGD there. In this paper, the monthly groundwater table's condition over 30 years is analyzed using monthly rainfall, snowfall, and the climate change index. Rainfall has been on an upward trend, but the snowfall has decreased over 40 years. Furthermore, the groundwater table at monitoring wells in the coastal area increased, as a result of the increased rainfall. However, the relationship between snowfall and groundwater is negative. As expected by Darcy's law, SGD flux was controlled by the hydraulic gradient of the coastal groundwater. The estimated historic SGD flux by groundwater table variation shows an upward trend of SGD. Considering the increase in precipitation and the groundwater table, SGD flux may increase under climate change.

  15. Improving Situational Awareness on Submarines Using Augmented Reality

    Science.gov (United States)

    2008-09-01

    COSO ) are several pages of guidance for the evolution available to the watch officer for reference. There are also Operating Procedures that the watch...officer must follow to ensure the safe ascent to PD. The COSOs are specific to the each CO. The OPs are specific to a class of submarine. The...evolution in the framework described above can provide valuable insight to the capabilities of the proposed system. This of course is a hypothetical

  16. Analysis of SSN 688 Class Submarine Maintenance Delays

    Science.gov (United States)

    2017-06-01

    errors an in-depth analysis into the job-level maintenance is required which is outside the scope of this analysis. 25 2. New Work Causes Late...attempting to determine the cause of this trend. Finally, this thesis proposes a solution to the systematic underestimation of availability durations by...illustrating the inherent error in the current equation and providing a notional equation to remove that error . 14. SUBJECT TERMS Submarine

  17. Submarine Pressure Hull Collapse Considering Corrosion and Penetrations

    Science.gov (United States)

    2010-11-01

    corrosion. Des valeurs de la pression d’écrasement sont calculées pour les diverses dimensions de la zone de corrosion, et ce, dans les cas de présence ou...Research & Development Canada DRDIM Director Research and Development Knowledge and Information Management OOC Out-of-circularity R&D Research...Support SLA (Mr. John Porter) 1 Project Manager , Submarine Scientific Support SLA (LCdr Wade Temple) 9 TOTAL LIST PART I LIST PART II: External

  18. Europe’s Grand Canyon: Nazaré submarine canyon

    OpenAIRE

    Tyler, P.; Amaro, T.; Arzola, R.; Cunha; Stigter, H. de; Gooday, A.; Huvenne, V.; Ingels, J; Kiriakoulakis, K; Lastras, G.; Masson, D.; Oliveira, A.; Pattenden, A.; Vanreusel, A.; van Weering, T.

    2009-01-01

    The Nazare submarine canyon extends similar to 210 km westward from the coast of Portugal, down to a water depth of > 4300 m. The considerable habitat heterogeneity found throughout the canyon is affected by strong currents and high turbidity, especially in the upper parts of the canyon. The canyon morphology comprises steep slopes, scarps, terraces, and overhangs, and a deeply incised thalweg is found in the lower part of the canyon. The seabed within the canyon is composed of varying propor...

  19. Submarine and Autonomous Vessel Proliferation: Implications for Future Strategic Stability at Sea

    Science.gov (United States)

    2012-12-01

    replace the Ohio- class SSBN and Virginia -class SSN to replace the Los Angeles class attack submarine. Although more sophisticated than their...predecessors and with some modifications to demands of the post-Cold War era and (in the Virginia class) an emphasis on littoral conflict, these purchases...Congressional Research Service analyst Amy Woolf observes: “With few submarines in the fleet, the Navy would have to reduce the number of submarines on

  20. The future of the ballistic missile submarine force in the Russian nuclear triad

    OpenAIRE

    Lesiw, Richard T.

    2008-01-01

    Approved for public release; distribution is unlimited This thesis analyzes the current status of the Russian Federation's ballistic missile submarine force. It reviews the history of the ballistic missile submarine force, its current status, and the implementation of plans currently in progress and as well as the advantages and disadvantages of maintaining a ballistic missile submarine force. This thesis also assesses the other two legs of the nuclear triad - the intercontinental balli...

  1. Gender Integration on U.S. Navy Submarines: Views of the First Wave

    Science.gov (United States)

    2015-06-01

    submarines is to perform seek-and-destroy missions on enemy ships and submarines, conduct surveillance and reconnaissance, provide covert troop insertion...not only the missile payload they were designed to carry but also extended periods at sea without resupply. In terms of berthing and sanitary ...officer berthing and sanitary 28 facilities on board Ohio class submarines, however, no significant modifications would be necessary in order to

  2. Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress

    Science.gov (United States)

    2016-02-12

    reactors or non- nuclear power sources such as diesel engines or fuel cells. All U.S. Navy submarines are nuclear - powered. A submarine’s use of...the Navy’s plan to design and procure a next - generation ballistic missile submarine called the Ohio Replacement Program or SSBN(X). 26...the next several years require these submarines to use up their nuclear fuel cores more quickly than the Navy now projects, then the amounts of time

  3. Introduction to the special issue on submarine geohazard records and potential seafloor instability

    Directory of Open Access Journals (Sweden)

    Song-Chuen Chen Jia-Jyun Dong

    2018-01-01

    Full Text Available Submarine landslides frequently occur in passive continental margins or active margins (Hampton et al. 1996; Wynn et al. 2000; Mienert et al. 2002; Korup et al. 2007; Twichell et al. 2009; Cukur et al. 2016. Submarine landslides have been studied extensively not only for scientific research but also for submarine geohazards. Submarine landslides could jeopardize marine infrastructures, such as offshore drilling platforms or submarine telecommunication cables, and could even trigger disastrous tsunamis (Bondevik et al. 2005; Harbitz et al. 2006; Hornbach et al. 2007, 2008; Hsu et al. 2008; Su et al. 2012; Tappin et al. 2014; Li et al. 2015. For instance, one disastrous tsunami hitting the coastal area of southwestern Taiwan in 1781 or 1782 was reported (Chen 1830; Hsu 1983; the tsunami event was probably generated by submarine landslides in the offshore area of southwestern Taiwan (Li et al. 2015. Moreover, several submarine landslides triggered by the 2006 Pingtung earthquake have induced turbidity currents off southwest Taiwan and destroyed about 14 submarine telecommunication cables off SW Taiwan (Hsu et al. 2008. The area of southwest Taiwan currently has a dense population (more than 3 million people in total, one deep-water Kaohsiung Port, several tanks of liquefied natural gas and a nuclear power plant on the coast (Fig. 1. Numerous submarine telecommunication cables exist off SW Taiwan. If a considerable tsunami event would hit again the costal area of SW Taiwan, the damage could very serious. Likewise, there are two nuclear power plants on the coast of northern Taiwan (Fig. 2, and the population in northern Taiwan has more than 10 million people. Submarine telecommunication cables also exist off northern Taiwan. In any case, it is important to understand the status of seafloor stability in the offshore areas of SW and NE Taiwan. For that, this special issue of submarine geohazard records and potential seafloor instability is aimed to

  4. Navy Virginia (SSN 774) Class Attack Submarine Procurement: Background and Issues for Congress

    Science.gov (United States)

    2016-10-25

    powered attack submarines (SSNs). The SSNs are general -purpose submarines that can (when appropriately equipped and armed) perform a variety of...signs of tampering. The defective elbow pipe, used to funnel steam from the reactor to the sub’s propulsion turbines and generators , showed evidence of...Congressional Research Service Summary The Navy has been procuring Virginia (SSN-774) class nuclear- powered attack submarines since FY1998. The two Virginia

  5. Fuel-cell-propelled submarine-tanker-system study

    Energy Technology Data Exchange (ETDEWEB)

    Court, K E; Kumm, W H; O' Callaghan, J E

    1982-06-01

    This report provides a systems analysis of a commercial Arctic Ocean submarine tanker system to carry fossil energy to markets. The submarine is to be propelled by a modular Phosphoric Acid Fuel Cell system. The power level is 20 Megawatts. The DOE developed electric utility type fuel cell will be fueled with methanol. Oxidant will be provided from a liquid oxygen tank carried onboard. The twin screw submarine tanker design is sized at 165,000 deadweight tons and the study includes costs and an economic analysis of the transport system of 6 ships. The route will be under the polar icecap from a loading terminal located off Prudhoe Bay, Alaska to a transshipment facility postulated to be in a Norwegian fjord. The system throughput of the gas-fed methanol cargo will be 450,000 barrels per day. The total delivered cost of the methanol including well head purchase price of natural gas, methanol production, and shipping would be $25/bbl from Alaska to the US East Coast. Of this, the shipping cost is $6.80/bbl. All costs in 1981 dollars.

  6. Estimating the empirical probability of submarine landslide occurrence

    Science.gov (United States)

    Geist, Eric L.; Parsons, Thomas E.; Mosher, David C.; Shipp, Craig; Moscardelli, Lorena; Chaytor, Jason D.; Baxter, Christopher D. P.; Lee, Homa J.; Urgeles, Roger

    2010-01-01

    The empirical probability for the occurrence of submarine landslides at a given location can be estimated from age dates of past landslides. In this study, tools developed to estimate earthquake probability from paleoseismic horizons are adapted to estimate submarine landslide probability. In both types of estimates, one has to account for the uncertainty associated with age-dating individual events as well as the open time intervals before and after the observed sequence of landslides. For observed sequences of submarine landslides, we typically only have the age date of the youngest event and possibly of a seismic horizon that lies below the oldest event in a landslide sequence. We use an empirical Bayes analysis based on the Poisson-Gamma conjugate prior model specifically applied to the landslide probability problem. This model assumes that landslide events as imaged in geophysical data are independent and occur in time according to a Poisson distribution characterized by a rate parameter λ. With this method, we are able to estimate the most likely value of λ and, importantly, the range of uncertainty in this estimate. Examples considered include landslide sequences observed in the Santa Barbara Channel, California, and in Port Valdez, Alaska. We confirm that given the uncertainties of age dating that landslide complexes can be treated as single events by performing statistical test of age dates representing the main failure episode of the Holocene Storegga landslide complex.

  7. Pockmark morphology and turbulent buoyant plumes at a submarine spring

    Science.gov (United States)

    Buongiorno Nardelli, B.; Budillon, F.; Watteaux, R.; Ciccone, F.; Conforti, A.; De Falco, G.; Di Martino, G.; Innangi, S.; Tonielli, R.; Iudicone, D.

    2017-09-01

    The input flow of groundwater from the seabed to the coastal ocean, known as Submarine Groundwater Discharge (SGD), has been only recently recognized as an important component of continental margin systems. It potentially impacts physical, chemical and biological marine dynamics. Independently of its specific nature (seepage, submarine springs, etc.) or fluid chemical composition, a SGD is generally characterized by low flow rates, hence making its detection and quantification very difficult, and explaining why it has been somewhat neglected by the scientific community for a long time. Along with the growing interest for SGDs emerged the need for in-situ observations in order to characterize in details how these SGDs behave. In this work, we describe the morphology of a pockmark field, detected in the Southern Tyrrhenian Sea (Mediterranean Sea), and provide observational evidences of the presence of active submarine springs over the coastal shelf area. We describe the effect of the fluid seeps on the water column stratification close to the main plumes and in the neighbouring areas, providing quantitative estimates of the intensity of the turbulent mixing and discussing their potential impact on the seabed morphology and pockmark formation in the context of turbulent buoyant plumes analytical modelling.

  8. Long-term eruptive activity at a submarine arc volcano.

    Science.gov (United States)

    Embley, Robert W; Chadwick, William W; Baker, Edward T; Butterfield, David A; Resing, Joseph A; de Ronde, Cornel E J; Tunnicliffe, Verena; Lupton, John E; Juniper, S Kim; Rubin, Kenneth H; Stern, Robert J; Lebon, Geoffrey T; Nakamura, Ko-ichi; Merle, Susan G; Hein, James R; Wiens, Douglas A; Tamura, Yoshihiko

    2006-05-25

    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes.

  9. Alongshore Distribution of Washover Deposits: Hurrcane Ike and the Texas Coast, 2008

    Science.gov (United States)

    Aylward, D.; Swartz, J. M.; Goudge, T. A.; Mohrig, D. C.

    2016-12-01

    Using aerial photos and airborne lidar collected from before and after Hurricane Ike, September 2008, we have mapped, measured, and examined the washover fans the storm produced from High Island to nearly Corpus Christi, TX. Specific attention was payed to defining the spatial change in the number, morphology and volume of the fans from where Ike made landfall, the northern end of Galveston Island, to the last observed washover fan, on the southern end of Matagorda Island. This stretch of 240km of coast corresponds with the drop in maximum storm surge height from 5m to 1m, elevations we compared to the local height of the back beach dune crest. Following Donnelly et al. 2006 we divide washover deposits into three morphological classes based on their later continuity: sheetwash, washover terraces, and washover fans. Sheetwash is laterally unconfined and is the result of complete berm remobilization by the storm surge. Washover fans are discrete deposits that result from the beach dunes being breached at a single location, while washover terraces form when several fans overlap. The storm and lidar data show that sheetwash deposition was limited to shoreline positions where the ratio of storm-surge to dune-crest height exceeded 0.6 and washover terraces were seldom observed at locations with ratio values less than 0.5. The analysis presented here allows us to refine the criteria used to identify factors allowing overwash to happen in some places but not others.

  10. Apparent resistivity and spectral induced polarization in the submarine environment

    Directory of Open Access Journals (Sweden)

    HERCULES DE SOUZA

    2001-09-01

    Full Text Available Relatively few investigations have employed electrical methods in the submarine environment, which may be promising for mineral deposits or threatened by environmental problems. We have measured the electric field using both disk and bar electrodes in the sea water at three different levels: sea surface, seven meters deep, and sea bottom at a depth of ten meters, employing a 2 m spacing dipole-dipole array with 7 array spacings of investigation, and 13 values of frequencies at steps of (2N hertz, N = -2, -1, 0, 1, 2,.....10. The measurement allowed the analysis of the electric field as a function of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fit with previous drilling data. Analysis of the spectrum of the complex apparent resistivity and the comparison with equivalent circuits, provided information about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of the present research show the feasibility of measuring the variation of seawater resistivity in situ, as well as the resistivity of sea bottom sediments.Relativamente poucas investigações têm empregado métodos elétricos no ambiente submarino, o qual pode ser promissor para depósitos minerais ou ameaçado por problemas ambientais. Nós medimos o campo elétrico usando eletrodos em forma de disco e de barra na água do mar, em três níveis distintos: superfície, sete metros de profundidade, e fundo do mar a dez metros de profundidade, empregando um dispositivo dipolo-dipolo com 2m de afastamento, 7 níveis de investigação e 13 valores de freqüência a intervalos de (2N hertz, N = -2, -1, 0, 1, 2, ... 10. A medida permitiu a análise do campo elétrico como uma função de freqüência e afastamento, e da polarização induzida espectral. A modelagem e a interpretação da resistividade aparente se ajustaram bem

  11. Developing a Luminescence Chronology for Fan-terrace Sediments, Los Cabos, Baja California, Mexico

    Science.gov (United States)

    Rhodes, E. J.; Brown, N. D.; Antinao, J.; Huenupi, E. C.; Baker, S. E.; McDonald, E.

    2012-12-01

    Extensive depositional units forming large terrace units within alluvial fans close to the southern tip of Baja California, Mexico, record sedimentation under a very different climatic regime from the present. Dating these sediments presents significant challenges; they contain very sparse organic material suitable for radiocarbon dating; their upper surfaces are heavily bioturbated, in some places eroded and in other locations show signs of continued deposition even after incision and base level fall, rendering them difficult to date using TCN (terrestrial cosmogenic nuclide) methods. Locations that have experienced significant regional tectonic influences associated with rapid erosion (e.g. Transverse Ranges, California, Southern Alps, New Zealand, Himalaya and Tibet) are typically not well-suited for quartz OSL (optically stimulated luminescence) application owing to low signal sensitivity. For this reason, our efforts to develop a chronology for the sandy sediments that characterize these contexts have focussed on IRSL dating of K-feldspar, using newly developed post-infrared IRSL (infra-red stimulated luminescence) approaches. We explore the relative advantages of different techniques, and methods to assess both the degree of incomplete zeroing and signal fading. In particular, we explore how novel single grain IRSL measurements of K-feldspar can be applied to these and similar high energy deposits on timescales ranging from the last 100,000 years to a few decades. Based on our chronology coupled with detailed sedimentological and soil stratigraphy investigations, we are able to exploit these deposits as valuable archives of past environmental and climatic change.

  12. Potential tsunamigenic hazard associated to submarine mass movement along the Ionian continental margin (Mediterranean Sea).

    Science.gov (United States)

    Ceramicola, S.; Tinti, S.; Praeg, D.; Zaniboni, F.; Planinsek, P.

    2012-04-01

    Submarine mass movements are natural geomorphic processes that transport marine sediment down continental slopes into deep-marine environments. Type of mass wasting include creep, slides, slump, debris flows, each with its own features and taking place over timescale from seconds to years. Submarine landslides can be triggered by a number of different causes, either internal (such as changes in physical chemical sediment properties) or external (e.g. earthquakes, volcanic activity, salt movements, sea level changes etc.). Landslides may mobilize sediments in such a way as to form an impulsive vertical displacement of a body of water, originating a wave or series of waves with long wavelengths and long periods called tsunamis ('harbor waves'). Over 600 km of continental margin has been investigated by OGS in the Ionian sea using geophysical data - morpho-bathymetry (Reson 8111, 8150) and sub-bottom profiles (7-10 KHz) - collected aboard the research vessel OGS Explora in the framework of the MAGIC Project (Marine Geohazard along the Italian Coasts), funded by the Italian Civil Protection. The objective of this project is the definition of elements that may constitute geological risk for coastal areas. Geophysical data allowed the recognition of four main types of mass wasting phenomena along the slopes of the ICM: 1) mass transport complexes (MTCs) within intra-slope basins. Seabed imagery show the slopes of all the seabed ridges to be marked by headwall scarps recording widespread failure, multiple debris flows in several basins indicate one or more past episodes of failure that may be linked to activity on the faults bounding the structural highs. 2) submarine landslide - a multiple failure event have been identified (Assi landslide) at about 6 km away from the coastline nearby Riace Marina. Headwall scars up to 50 m high across water depths of 700 to 1400 m, while sub-bottom profiles indicate stacked slide deposits at and near seabed. 4) canyon headwalls - in the

  13. SUBMARINE VOLCANO CHARACTERISTICS IN SABANG WATERS

    Directory of Open Access Journals (Sweden)

    Hananto Kurnio

    2017-07-01

    Full Text Available The aim of the study is to understand the characteristics of a volcano occurred in marine environment, as Weh Island where Sabang City located is still demonstrated its volcanic cone morphology either through satellite imagery or bathymetric map. Methods used were marine geology, marine geophysics and oceanography. Results show that surface volcanism (sea depth less than 50 m take place as fumaroles, solfataras, hot ground, hot spring, hot mud pool and alteration in the vicinities of seafloor and coastal area vents. Seismic records also showed acoustic turbidity in the sea water column due to gas bubblings produced by seafloor fumaroles. Geochemical analyses show that seafloor samples in the vicinities of active and non-active fumarole vent are abundances with rare earth elements (REE. These were interpreted that the fumarole bring along REE through its gases and deposited on the surrounding seafloor surface. Co-existence between active fault of Sumatra and current volcanism produce hydrothermal mineralization in fault zone as observed in Serui and Pria Laot-middle of Weh Island which both are controlled by normal faults and graben.

  14. Numerical Study of Transition of an Annular Lift Fan Aircraft

    Directory of Open Access Journals (Sweden)

    Yun Jiang

    2016-09-01

    Full Text Available The present study aimed at studying the transition of annular lift fan aircraft through computational fluid dynamics (CFD simulations. The oscillations of lift and drag, the optimization for the figure of merit, and the characteristics of drag, yawing, rolling and pitching moments in transition are studied. The results show that a two-stage upper and lower fan lift system can generate oscillations of lift and drag in transition, while a single-stage inner and outer fan lift system can eliminate the oscillations. The characteristics of momentum drag of the single-stage fans in transition are similar to that of the two-stage fans, but with the peak of drag lowered from 0.63 to 0.4 of the aircraft weight. The strategy to start transition from a negative angle of attack −21° further reduces the peak of drag to 0.29 of the weight. The strategy also reduces the peak of pitching torque, which needs upward extra thrusts of 0.39 of the weight to eliminate. The peak of rolling moment in transition needs differential upward thrusts of 0.04 of the weight to eliminate. The requirements for extra thrusts in transition lead to a total thrust–weight ratio of 0.7, which makes the aircraft more efficient for high speed cruise flight (higher than 0.7 Ma.

  15. An intelligent FFR with a self-adjustable ventilation fan.

    Science.gov (United States)

    Zhou, Song; Li, Hui; Shen, Shengnan; Li, Siyu; Wang, Wei; Zhang, Xiaotie; Yang, James

    2017-11-01

    This article presents an intelligent Filtering Facepiece Respirator (FFR) with a self-adjustable ventilation fan for improved comfort. The ventilation fan with an intelligent control aims to reduce temperature, relative humidity, and CO2 concentrations inside the facepiece. Compared with a previous version of the FFR, the advantage of this new FFR is the intelligent control of the fan's rotation speed based on the change in temperature and relative humidity in the FFR dead space. The design of the control system utilizes an 8-bit, ultra-low power STC15W404AS microcontroller (HongJin technology, Shenzhen, China), and adopts a high-precision AM2320 device (AoSong electronic, Guangzhou, China) as temperature and relative humidity sensor so that control of temperature and relative humidity is realized in real time within the FFR dead space. The ventilation fan is intelligently driven and runs on a rechargeable lithium battery with a power-save mode that provides a correspondingly longer operational time. Meanwhile, the design is simplistic. Two experiments were performed to determine the best location to place the fan.

  16. Evolution of submarine eruptive activity during the 2011-2012 El Hierro event as documented by hydroacoustic images and remotely operated vehicle observations

    Science.gov (United States)

    Somoza, L.; González, F. J.; Barker, S. J.; Madureira, P.; Medialdea, T.; de Ignacio, C.; Lourenço, N.; León, R.; Vázquez, J. T.; Palomino, D.

    2017-08-01

    Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011 to 2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As a result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash, vesicular lapilli and formed high-density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.Plain Language SummaryToday and through most of geological history, the greatest number and volume of volcanic eruptions on Earth have occurred underwater. However, in comparison to subaerial eruption, little is known about submarine eruptive processes as they are dangerous to cruise it over

  17. "I'm Buffy, and you're history": Putting fan studies into history [editorial

    Directory of Open Access Journals (Sweden)

    Nancy Reagin

    2011-03-01

    Full Text Available This essay kicks off the special historical issue of Transformative Works and Cultures by offering an overview of the ways in which fan communities have been studied by academic historians, and how fan studies has written the history of fan communities. The essay discusses historical work done by amateur fan historians throughout the 20th century; what academic historians can offer fan communities; why academic historians could benefit from studying fandoms as part of the history of popular culture; and what fan studies as a discipline might gain from a broader historical analysis of fandoms.

  18. Can submarine groundwater discharge be a major source of mercury input to north Gulf of Mexico?

    Science.gov (United States)

    Du, X.; Das, R.; Odom, L.

    2009-12-01

    Atmosphere deposition is generally regarded to be the primary source of mercury in the open ocean. Bone et al., 2007 measured an order of magnitude higher mercury concentration (0.47-1.9 nM of Hg m-2 day-1) in the submarine ground water discharge to the Waquoit Bay (Massachusetts), than the atmospheric deposition rate for the northeastern U.S and far greater than the dissolved Hg introduced through riverine input. This is a report initial findings of an investigation begun in April, 2009 to study what role submarine groundwater discharge along the northern Gulf of Mexico coast (Florida) might have in supplying dissolved mercury and methylmercury to gulf waters. Initial efforts have concentrated on part of a pristine and previously studied (Santos et al., 2008) subterranean estuary. The subterranean estuary is the zone in which encroaching seawater mixes with groundwater from land-based recharge. We collected water samples from five permanent PVC wells over small spatial scales (~ 10 m), sampling the subterranean estuary water at 4 m depth. Fresh groundwater and sea water were collected as well. Within the narrow subterranean estuary zone of the study area, both total dissolved mercury and methylmercury filtered samples reach concentrations nearly two orders of magnitude higher than that in either of the presumed end members (groundwater and seawater). Peak concentrations are approximately in the center of the zone (total mercury = 99.7 pM; methylmercury=16.9 pM). By comparison, Sunderland et al. (2009) found methylmercury concentration in North Pacific Ocean water to be 0.33pM. Isotopic measurements of mercury across the subterranean estuary zone reveal a mass-dependent fractionation pattern of heavy isotope enrichment increasing from δ202Hg = 0.1 (landward) to 1.1 (seaward). { δ202Hg = [(202Hg/200Hg)water/(202Hg/200Hg)NIST3133] -1x1000} Because of the low concentrations, isotopic measurements of seawater and groundwater are not presently available. While no

  19. Antidunes: new insights on processes and deposits

    Science.gov (United States)

    Leclair, Suzanne

    2014-05-01

    This talk presents :1) a brief review of the development of our understanding of antidune processes and deposits; 2) results from the author's current collaborative studies, and; 3) points out key issues to be addressed in future research on upper-regime bedforms and sedimentary structures. Antidunes deposits may be overlooked or incorrectly interpretated in the sedimentary record. In alongstream direction, their preserved sedimentary structures resemble dune trough-cross stratification while accros-stream sections show mostly planar beds. Antidune strata can be structureless, and hence similar to some chute-and-pool, or hydraulic-jumps deposits. Moreover, recognition of antidune stratification in nature may also be hampered by the spatial limitation of exposures compared to the scale of the formative bedforms. However, antidune signature presents internal distinctive stratal and textural features that were revealed by experimental investigation and observation in modern fluvial deposits. The main results come from the comparative image analysis of video records and photographs of sediment samples (sediment peels) from flume experiments with upper-stage, open-flow conditions. These results brough new insights on antidune migration processes and deposition /erosion sequences, allowing to revise the traditional model typically presented in texbooks. Differences do occur between deposition/erosion patterns of 'progresive' antidunes (not all antidunes break) and breaking antidunes, resulting in the (potential) preservation of spatially-limited strata with boundaries that define a sort of polygone within the overall deposits, and that can show 'clusters' of gravel (antidune signature may then be more apparent in sand-and-gravel sediment than in well-sorted sand). This specific sedimentary feature was obverved in modern deposits from a dryland river (where antidune can occur during flash floods). Otherwise, limited experimental data on submarine, super-critical , high

  20. Effect of Number of Blades on Performance of Ceiling Fans

    Directory of Open Access Journals (Sweden)

    Adeeb Ehsan

    2015-01-01

    Full Text Available In this paper, the effect of number of blades on ceiling fan performance is discussed. This approach helps to satisfy tradeoff between high air flow (performance and power consumption (energy efficiency. Specifically, variation from two to six blades is considered with nonlinear forward sweep profile. Reynolds Averaged Navier-Stokes (RANS technique is used to model the flow field induced by the ceiling fan inside a generic room. The performance is gauged through response parameters namely volumetric flow rate, mass flow rate, torque and energy efficiency. The results indicate that mass and volumetric flow rates are maximized for six blade configuration and energy efficiency is maximized for two blade configuration. The study indicates the importance of tradeoff between high air flow through ceiling fan and associated energy efficiency.

  1. Public Policies for footabll athletes and fans: arguments for disidents

    Directory of Open Access Journals (Sweden)

    Heloisa Helena Baldy dos Reis

    2014-06-01

    Full Text Available In this paper, we analyze to what extent and how the main laws and documents that support the Brazilian public policies for football athletes and fans establish and sustain relations of domination. For this, we rely on the literature available on the subject. In order to access to this literature, we made a review of the literature in several databases, where we used keywords that varied according to the mode of the databases organization and local terminology. Among other things, we conclude that these public policies maintain the domination of clubs and entrepreneurs over the athletes and the domination of the State over fans – especially, over the organized groups of fans.

  2. Procedure for Balancing an Air Distribution System with Decentralised Fans

    DEFF Research Database (Denmark)

    Gunner, Amalie; Hultmark, Göran; Vorre, Anders

    2015-01-01

    This paper presents results from an on-going project concerning new design procedures for mechanical ventilation systems with low energy use. Conventional constant air volume (CAV) systems are usually balanced using flat plate dampers. The purpose of using balancing dampers is to intentionally...... introduce pressure drops in the duct system thus nominal airflows are achieved throughout the ductwork within specified tolerances. However, introduction of pressure drops will increase energy requirement for the ventilation system and in addition, balancing a duct system is a time consuming task and often...... flawed. This paper presents a new procedure for balancing of CAV systems in combination with decentralised fans. The new system was based on replacing the balancing dampers with decentralised fans. By replacing the balancing dampers with decentralised fans, airflows can be balanced by adjusting the speed...

  3. Using Mobile Marketing to Engage NASCAR Fans and Increase Sales

    Directory of Open Access Journals (Sweden)

    MARK DODDS

    2011-01-01

    Full Text Available Mobile marketing displays engage the consumer. This sponsorship activation tactic is highly visible at NASCAR races. Some common elements include show cars, interactive race simulators, video games and race suit/equipment displays. The authors of this study argue that by using mobile marketing effectively as a sponsorship activation tactic, the race fans derive more enjoyment from the race experience. This increased enjoyment links to higher product sales for the sponsor. The implications of this study show that sponsors in other sports should use mobile marketing to increase the fan satisfaction of the game experience in order to increase their product sales. Additionally, event mangers should support mobile marketing as a sponsorship activation tactic with the intention of increasing fan enjoyment and improving attendance.

  4. Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian Ocean

    Directory of Open Access Journals (Sweden)

    J. M. Schwab

    2012-08-01

    Full Text Available 2-D seismic data from the top and the western slope of Mergui Ridge in water depths between 300 and 2200 m off the Thai west coast have been investigated in order to identify mass transport deposits (MTDs and evaluate the tsunamigenic potential of submarine landslides in this outer shelf area. Based on our newly collected data, 17 mass transport deposits have been identified. Minimum volumes of individual MTDs range between 0.3 km3 and 14 km3. Landslide deposits have been identified in three different settings: (i stacked MTDs within disturbed and faulted basin sediments at the transition of the East Andaman Basin to the Mergui Ridge; (ii MTDs within a pile of drift sediments at the basin-ridge transition; and (iii MTDs near the edge of/on top of Mergui Ridge in relatively shallow water depths (< 1000 m. Our data indicate that the Mergui Ridge slope area seems to have been generally unstable with repeated occurrence of slide events. We find that the most likely causes for slope instabilities may be the presence of unstable drift sediments, excess pore pressure, and active tectonics. Most MTDs are located in large water depths (> 1000 m and/or comprise small volumes suggesting a small tsunami potential. Moreover, the recurrence rates of failure events seem to be low. Some MTDs with tsunami potential, however, have been identified on top of Mergui Ridge. Mass-wasting events that may occur in the future at similar locations may trigger tsunamis if they comprise sufficient volumes. Landslide tsunamis, emerging from slope failures in the working area and affecting western Thailand coastal areas therefore cannot be excluded, though the probability is very small compared to the probability of earthquake-triggered tsunamis, arising from the Sunda Trench.

  5. Noise and vibration analysis for automotive radiator cooling fan

    Science.gov (United States)

    Razak, N. F. D.; Sani, M. S. M.; Azmi, W. H.; Zhang, B.

    2017-10-01

    This paper aims to analyse the noise and vibration of the automotive radiator specifically focused on its cooling fan for different fan conditions and different coolants used namely Ethylene Glycol (EG) water-based and Titanium Oxide (TiO2) nanofluid. Noise source identification is carried out by utilizing the sound intensity mapping method while an accelerometer is used to measure the vibration results. Both of these experiments are conducted when the fan was both in static and working conditions. The maximum cooling fan speed for the working fan detected by a tachometer for EG water-based is 1990 rpm while TiO2 nanofluid is 2030 rpm. The difference in speed is due to the different physical properties such viscosity of each coolant has where TiO2 nanofluid has lower viscosity than EG water-based. The maximum sound power level produced by EG water-based is 53.73 dB while TiO2 nanofluid is 101.94 dB. Meanwhile, the vibration frequencies of EG water-based are higher than TiO2 nanofluid. The noise level increases with the cooling fan speed but decreases with the vibration frequency. Apart from studying the noise and vibration of the automotive radiator, this research also analysed the potential application using nanofluid due to its great properties according to its major use in the heat transfer enhancement. As a conclusion, nanofluid as a radiator coolant could improve heat transfer rate, and could also reduce the presence of vibration in the automotive cooling system.

  6. Automatic Lamp and Fan Control Based on Microcontroller

    Science.gov (United States)

    Widyaningrum, V. T.; Pramudita, Y. D.

    2018-01-01

    In general, automation can be described as a process following pre-determined sequential steps with a little or without any human exertion. Automation is provided with the use of various sensors suitable to observe the production processes, actuators and different techniques and devices. In this research, the automation system developed is an automatic lamp and an automatic fan on the smart home. Both of these systems will be processed using an Arduino Mega 2560 microcontroller. A microcontroller is used to obtain values of physical conditions through sensors connected to it. In the automatic lamp system required sensors to detect the light of the LDR (Light Dependent Resistor) sensor. While the automatic fan system required sensors to detect the temperature of the DHT11 sensor. In tests that have been done lamps and fans can work properly. The lamp can turn on automatically when the light begins to darken, and the lamp can also turn off automatically when the light begins to bright again. In addition, it can concluded also that the readings of LDR sensors are placed outside the room is different from the readings of LDR sensors placed in the room. This is because the light intensity received by the existing LDR sensor in the room is blocked by the wall of the house or by other objects. Then for the fan, it can also turn on automatically when the temperature is greater than 25°C, and the fan speed can also be adjusted. The fan may also turn off automatically when the temperature is less than equal to 25°C.

  7. Geomorphic evolution and sediment partitioning in the Tista Fan and Barind Tract areas, NW Bangladesh, during the Late Quaternary

    Science.gov (United States)

    Grimaud, J. L.; Grall, C.; Paola, C.; Goodbred, S. L., Jr.; Hossain, S.; Sincavage, R.; Pickering, J.; Steckler, M. S.; Seeber, L.; Cojan, I.; Franke, C.

    2016-12-01

    Characterizing surface dynamics at the input of deltas is key for understanding the behavior of rivers as well as the large scale partitioning of their sediments which has implications on stratigraphic architectures and delta-surface evolution. Indeed, the ability of a river system to either efficiently migrate laterally or to persist at a single location through time has repercussions downstream. At the front of mountain ranges, underlying surface deformation and transverse sediment delivery from large alluvial fans (megafans) can steer rivers thus affecting their behavior. In this study, we are interested in the area of NW Bangladesh that is bounded by the Brahmaputra and Ganges rivers (Barind Tract and Tista Fan). We use field reconnaissance as well as a survey of 70 boreholes to characterize surface geomorphology and subsurface deposits. Bulk sediment Sr measurements have enabled us to identify provenance and map the evolution of the Tista Fan boundaries through the Holocene. We find that these boundaries are overall stable despite some changes through time to the east. The distribution of soils and paleosols shows distinctive patterns between the Tista Fan area and the Barind Tract: while the former shows the alternations of soils with various degrees of weathering and fine to coarse sand bodies, the latter forms a more consistently weathered sand accumulation capped by outcropping paleosols. Borehole samples show different types of paleosols between the East Barind Tract and the West Barind Tract, which forms a relative topographic high incised by both the Ganges and Tista rivers. We then analyze both sediment partitioning and geomorphic evolution with emphasis on the geometry of deep-structures. We combine gravity analysis and 2D flexural models that account for differential loading associated to both the tectonics (of the Himalaya Front mainly) and the sedimentation (of the Tista Fan and the Brahmaputra valley). We show that the Barind Tract is under

  8. Giant landslide deposits in northwest Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Fauque, L.; Strecker, M.R.; Bloom, A.L.

    1985-01-01

    Giant Quaternary landslide deposits occur along mountain fronts in the structural transition zone between the high-angle reverse-fault-bounded Sierras Pampeanas and the low-angle thrust belt of the Sierras Subandinas. There are two modes of occurrence: (1) chaotic masses without distinct geometry, and (2) masses with distinct lobate geometry similar to glacial moraines. Type (1) deposits occur where the moving rock mass followed a narrow valley and blocked the drainage. Many of these caused subsequent formation of lakes and changed the sedimentation processes on pediments at the mountain fronts. In type (2) deposits, lateral and frontal ridges are up to 10 m higher than the interior parts; in some places pressure ridges within the lobes are well preserved. Type (2) deposits show reverse grading and were deposited on relatively smooth pediments or alluvial fans. The lobate geometry strongly suggests that type (2) deposits are a product of flowage and are debris stream or sturzstrom deposits (sense of Heim, 1932 and Hsu, 1975). All investigated deposits occur in areas of demonstrated Quaternary faulting and are interpreted as the result of tectonic movements, although structural inhomogeneities in the source area may have been a significant factor for some of the landslides. No datable materials have yet been found associated with the deposits.

  9. The Gyra washover fan in the Lefkada Lagoon, NW Greece—possible evidence of the 365 AD Crete earthquake and tsunami

    Science.gov (United States)

    May, Simon Matthias; Vött, Andreas; Brückner, Helmut; Smedile, Alessandra

    2012-10-01

    Coastal geomorphological and geological archives store valuable information about the geodynamic evolution of coastal areas and the contributing geomorphodynamic processes. The coastal geomorphology of the Lefkada- Preveza coastal zone, NW Greece, holds evidence for the influence of both gradual, low-energy and episodic, high-energy coastal processes. Situated close to the Hellenic Arc and the Cefalonia transform fault, the area belongs to one of the seismically most active regions in the Mediterranean. Thus, tsunami events are assumed to have contributed to the coastal evolution in the study area according to tsunami catalogues and field evidence from previous investigations. The northern part of the Lefkada Lagoon, separated from the Ionian Sea by an extensive barrier beach system, is characterized by a number of fan-like washover structures, formed by different washover generations. In this paper, we present detailed geomorphological, sedimentological, geochemical and foraminiferal investigations on the most prominent fan structure, the Gyra fan, based on terrestrial and lagoonal sediment cores. The Gyra fan consists of a coarse-grained sequence of fully marine origin on top of lagoonal mud and a palaeosol, respectively. The sequence shows numerous characteristics of extreme wave deposits. Due to the dimension and morphology of the fan, the existence of up to four consistent and correlative stratigraphic subunits, their landward thinning and their comparable sedimentary characteristics, we argue that a tsunami event induced the formation of the Gyra fan, comprising at least four major inundation impulses. According to radiocarbon dates, this geomorphological structure was most likely formed by teletsunami effects triggered by the 365 AD earthquake off western Crete.

  10. Foundation analyzing of centrifugal ID fans in cement pla

    Directory of Open Access Journals (Sweden)

    Hamid Eskandari

    2016-06-01

    Full Text Available This research was based on a finite-element model (FEM of large foundations such as induced draft (ID fans. Three-dimensional (3D linear analyses were performed under arbitrary static and dynamic loads for various modulus of elasticity of concrete (Ec (20, 25, 28 and 30 GPa and reinforcement (Es (200, 250, 300 GPa. FEM results were compared with the existing ID fan foundations (laboratory-based evidence to assess the accuracy of simulations made by the FEM. This study validated what constitutes a major departure from current thinking regarding material properties modeling of concrete under various loads to increase foundation for lifetime.

  11. Foundation analyzing of centrifugal ID fans in cement plants

    OpenAIRE

    Eskandari, Hamid; Nik, Morteza; Pakzad, Amir

    2017-01-01

    This research was based on a finite-element model (FEM) of large foundations such as induced draft (ID) fans. Three-dimensional (3D) linear analyses were performed under arbitrary static and dynamic loads for various modulus of elasticity of concrete (Ec) (20, 25, 28 and 30 GPa) and reinforcement (Es) (200, 250, 300 GPa). FEM results were compared with the existing ID fan foundations (laboratory-based evidence) to assess the accuracy of simulations made by the FEM. This study validated what c...

  12. Test of a Dual-Rotation Axial Flow Fan

    Science.gov (United States)

    1942-12-01

    METRO~ OF T~STiaG Pruc~din~ thu actual testA of tho fan, tho torque out~ut of oac~ motor was calib~atod with R Prony brako again~t wattm3t~r and...2 1 I .z .3 fit (c/) ,f’Qn ’FFiciencl•~· F&un 7.- Concllld«<. ~ 1-¥" / r\\ .~ If ~ - 31 .,; .6 - I --. i ~ ~, -~ 1-. \\ ~ ..5fJ"\\. 40...calibrated with Prony brake against «attceter and voltr.eter readings. Fan was tested with various combinations of front and rear blade angles and

  13. Fan Flutter Computations Using the Harmonic Balance Method

    Science.gov (United States)

    Bakhle, Milind A.; Thomas, Jeffrey P.; Reddy, T.S.R.

    2009-01-01

    An experimental forward-swept fan encountered flutter at part-speed conditions during wind tunnel testing. A new propulsion aeroelasticity code, based on a computational fluid dynamics (CFD) approach, was used to model the aeroelastic behavior of this fan. This threedimensional code models the unsteady flowfield due to blade vibrations using a harmonic balance method to solve the Navier-Stokes equations. This paper describes the flutter calculations and compares the results to experimental measurements and previous results from a time-accurate propulsion aeroelasticity code.

  14. "Cultural acupuncture": Fan activism and the Harry Potter Alliance

    Directory of Open Access Journals (Sweden)

    Henry Jenkins

    2012-06-01

    Full Text Available Fan activists have struggled to defend series from cancellation, defend themselves from cease and desist orders, promote alternative representations, and raise money for charity. Building on this background, this article examines how the Harry Potter Alliance encourages young people to speak out as fans on a broad range of human rights and social justice issues through what the group's leader, Andrew Slack, calls "cultural acupuncture." The group's practice of mapping the fictional content world onto real-world concerns helps empower young people to become civicly engaged and politically active.

  15. Refining the Bengal Fan stratigraphy - A first correlation of IODP Expedition 354 results and seismic data from the Bay of Bengal

    Science.gov (United States)

    Schwenk, Tilmann; Spiess, Volkhard; Bergmann, Fenna; France-Lanord, Christian; Klaus, Adam

    2016-04-01

    The Bengal Fan covers the floor of the entire Bay of Bengal from the continental margins of India and Bangladesh to the sediment-filled Sunda Trench off Myanmar and the Andaman Islands, and along the west side of the Ninetyeast Ridge. The deposition and progradation of the Bengal Fan started in the Eocene after the collision of India with Asia resulting in the build-up of the Himalaya and the formation of a large proto-Bay of Bengal. Continued convergence of the Indian and Australian plates with the Southeast Asian plate reduced the size of the bay and focused the source of turbidites finally into the present Bengal Basin, Bangladesh shelf, and the shelf canyon "Swatch of no Ground". Today, the Bengal Fan is mainly fed by the sediment load of the Ganges and Brahmaputra rivers, which drain the Himalayas at its southern and northern slope, respectively, and deliver their load to the delta in the Bengal Basin, to the Bengal Shelf and to the deep sea fan. Thus the Bengal Fan is a suitable recorder to study interactions among the growth of the Himalaya and Tibet, the development of the Asian monsoon, and processes affecting the carbon cycle and global climate. Because sedimentation in the Bengal Fan responds to both, climate and tectonic processes, its terrigenous sediment records the past evolution of both the Himalaya and regional climate. This evolution is also expressed in the stratigraphy of the fan in terms of unconformities and key horizons, average sedimentation rates as a function of distance from the basement ridges at 85°E and 90°E and the presence or absence of channel-levee systems. The histories of the Himalaya/Tibetan system and the Asian monsoon require sampling different periods of time with different levels of precision. Therefore IODP Expedition 354 drilled in February-March 2015 a seven site, 320 km-long transect across the Bengal Fan at 8°N. This strategy has been chosen because sediment transport took place by turbidity currents following

  16. Volcanic ash ingestion by a large gas turbine aeroengine: fan-particle interaction

    Science.gov (United States)

    Vogel, Andreas; Clarkson, Rory; Durant, Adam; Cassiani, Massimo; Stohl, Andreas

    2016-04-01

    Airborne particles from explosive volcanic eruptions are a major safety threat for aviation operations. The fine fraction of the emitted particles (aircraft encounters with drifting volcanic ash clouds. Particles ingested into the engine cause erosion of upstream surfaces of compressor fan blades and rotor-path components, and can also cause contamination or blockage of electrical systems and the fuel system such as fuel nozzles and air bleed filters. Ash particles that enter the hot-section of the engine (combustor and turbine stages; temperature between 1400-1800°C) are rapidly heated above the glass transition temperature (about 650-1000°C) and become soft (or form a melt) and can stick as re-solidified deposits on nozzle guide vanes. The glass deposits change the internal aerodynamic airflow in the engine and can affect the cooling capability of the different components by clogging the cooling inlets/outlets, which can lead to a loss of power or flame-out. The nature of volcanic ash ingestion is primarily influenced by the fan at the front of the engine which produces the thrust that drives the aircraft. The ingested air is split between the core (compressor/combustor/turbine) and bypass (thrust) at a ratio of typically between, 1:5-10 on modern engines. Consequently, the ash particles are fractionated between the core and bypass by the geometry and dynamics of the fan blades. This study uses computational fluid dynamics (CFD) simulations of particle-laden airflows into a turbofan engine under different atmospheric and engine operation conditions. The main aim was to investigate the possible centrifugal effect of the fan blades as a function of particle size, and to relate this to the core intake concentration. We generated a generic 3D axial high-bypass turbofan engine using realistic dimensions of the turbofan, engine intake and other aerodynamically relevant parts. The CFD experiments include three scenarios of aircraft performance (climb, cruise and

  17. Experimental studies of supercritical bedforms applied to coarse-grained turbidite deposits of the Tabernas Basin (SE Spain, late Miocene)

    Science.gov (United States)

    Cartigny, Matthieu; Postma, George; Kleverlaan, Kick

    2014-05-01

    Modern submarine canyon floors are often covered with bedform patterns linked to supercritical turbidity currents, while recognition of sedimentary structures associated with such bedforms in outcrops are rare. On the basis of experimental work on bed morphodynamics and flow structure of high-density turbidity currents, a 3-dimensional bedform stability diagram and related sedimentary facies diagram have been constructed. To allow scaling of this diagram to natural flows, four non-dimensional parameters are used: 1) densimetric Froude number, 2) modified mobility parameter, 3) dimensionless grain size and 4) basal sediment concentration. Each bedform and basal sediment concentration is then linked to a characteristic facies type. Numerical and theoretical models from the literature and observations from modern turbidite depositional systems are used to estimate characteristic sizes of the bedforms for different flow types. The model is applied to the turbidite fan systems of the Tabernas Basin (SE Spain, late Miocene) and discussed along existing classical models of high density turbidity current deposits. It is concluded that the vertical sequence of supercritical bedforms have been described in these models, yet to date have never been recognized as bedforms in outcrop, presumably because of their large size that easily exceeds the dimensions of commonly available outcrop. On the basis both experimental work and outcrop studies in the Tabernas Basin (SE Spain) a conceptual three-dimensional bedform diagram for recognition of cyclic steps in outcrop is constructed. Experimental data indicates that depositional processes on the stoss-side of a cyclic step are controlled by hydraulic jump, which temporarily stalls the flow and by subsequent waxing of the flow up to supercritical again. The hydraulic jump produces large scours with soft sediment deformation (flames) preserved in Bouma Ta, while near horizontal, massive to stratified top-cut-out turbidite beds are

  18. The Impact of the General Board of the Navy on Interwar Submarine Design

    Science.gov (United States)

    2009-06-12

    Navy had developed the Gato class submarine, which was successful independently operating in the vast Pacific Ocean in support of War Plan Orange. The...development of the Gato class submarine, which was successful independently operating in the vast Pacific Ocean in support of War Plan Orange. The...

  19. Procurements by the Non-Acoustic Anti-Submarine Warfare Program Through the Environmental Technologies Laboratory

    Science.gov (United States)

    1994-06-14

    General, DoD, on contract offloading, including Report No. 93-068, " Procurement of Services for the Non-Acoustic Anti-Submarine Warfare Program...contract administration in response to Audit Report No. 93-042. Report No. 93-068, " Procurement of Services for the Non-Acoustic Anti- Submarine Warfare

  20. Study on the locational criteria for submarine rock repositories of low and medium level radioactive wastes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G. H.; Kang, W. J.; Kim, T. J. and others [Chungnam National Univ., Taejon (Korea, Republic of)

    1992-01-15

    Submarine repositories have significant advantages over their land counterparts locating close to the areas of daily human activities. Consequently, the construction of submarine repositories on the vast continental shelves around Korean seas is considered to be highly positive. In this context, the development of locational criteria primarily targeting the safety of submarine rock repositories is very important.The contents of the present study are: analyzing characteristics of marine environment: Search of potential hazards to, and environmental impact by, the submarine repositories; Investigation of the oceanographic, geochemical, ecological and sedimentological characteristics of estuaries and coastal seas. Locating potential hazards to submarine repositories by: Bibliographical search of accidents leading to the destruction of submarine structures by turbidity currents and other potentials; Review of turbidity currents. Consideration of environmental impact caused by submarine repositories: Logistics to minimize the environmental impacts in site selection; Removal and dispersion processes of radionuclides in sea water. Analyses of oceanographical characteristics of, and hazard potentials in, the Korean seas. Evaluation of the MOST 91-7 criteria for applicability to submarine repositories and the subsequent proposition of additional criteria.

  1. The risk of hydrogen explosion in a submarine p.I Catalytic combustion of hydrogen

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2016-09-01

    Full Text Available The series of articles discuss issues related to conducting high risk projects on the example of modernisation of hydrogen incinerators on a submarine. The article depicts a technical problem situation connected with catalytic hydrogen combustion on a submarine.

  2. Historical Ground-Water Development in the Salinas Alluvial Fan Area, Salinas, Puerto Rico, 1900-2005

    Science.gov (United States)

    Rodriguez, Jose M.; Gómez-Gómez, Fernando

    2008-01-01

    The Salinas alluvial fan area has historically been one of the most intensively used agricultural areas in the South Coastal Plain of Puerto Rico. Changes in agricultural practices and land use in the Salinas alluvial fan have also caused changes in the geographic distribution of ground-water withdrawals from the alluvial aquifer. As a result, the ground-water balance and ground-water flow pattern have changed throughout the years and may explain the presence of saline ground water along parts of the coast at present. By providing a reconstruction of historical ground-water development in the Salinas alluvial fan area, from the initial years of aquifer development at about 1900 to the most recent conditions existing in 2005, water resources managers and planners can use the results of the analysis for a more complete understanding of aquifer conditions especially pertaining to water quality. This study effort was conducted by the U.S. Geological Survey in cooperation with the Puerto Rico Department of Natural and Environmental Resources as a contribution in the management of the Jobos Bay National Estuarine Research Reserve. The study area encompasses about 20 mi2 (square miles) of the extensive South Coastal Plain alluvial aquifer system (fig. 1). The study area is bounded to the north by foothills of the Cordillera Central mountain chain, to the south by the Caribbean Sea, and to the east and west by the Rio Nigua de Salinas and the Quebrada Aguas Verdes, respectively. Fan-delta and alluvial deposits contain the principal aquifers in the study area.

  3. Optimization of the Hockey Fans in Training (Hockey FIT) weight loss and healthy lifestyle program for male hockey fans.

    Science.gov (United States)

    Blunt, Wendy; Gill, Dawn P; Sibbald, Shannon L; Riggin, Brendan; Pulford, Roseanne W; Scott, Ryan; Danylchuk, Karen; Gray, Cindy M; Wyke, Sally; Bunn, Christopher; Petrella, Robert J

    2017-11-28

    The health outcomes of men continue to be poorer than women globally. Challenges in addressing this problem include difficulties engaging men in weight loss programs as they tend to view these programs as contrary to the masculine narrative of independence and self-reliance. Researchers have been turning towards sports fans to engage men in health promotion programs as sports fans are typically male, and tend to have poor health habits. Developed from the highly successful gender-sensitized Football Fans in Training program, Hockey Fans in Training (Hockey FIT) recruited 80 male hockey fans of the London Knights and Sarnia Sting who were overweight or obese into a weekly, 90-minute classroom education and group exercise program held over 12 weeks; a 40-week minimally-supported phase followed. A process evaluation of the Hockey FIT program was completed alongside a pragmatic randomized controlled trial and outcome evaluation in order to fully explore the acceptability of the Hockey FIT program from the perspectives of coaches delivering and participants engaged in the program. Data sources included attendance records, participant focus groups, coach interviews, assessment of fidelity (program observations and post-session coach reflections), and 12-month participant interviews. Coaches enjoyed delivering the program and found it simple to deliver. Men valued being among others of similar body shape and similar weight loss goals, and found the knowledge they gained through the program helped them to make and maintain health behaviour changes. Suggested improvements include having more hockey-related information and activities, greater flexibility with timing of program delivery, and greater promotion of technology support tools. We confirmed Hockey FIT was an acceptable "gender-sensitized" health promotion program for male hockey fans who were overweight or obese. Minor changes were required for optimization, which will be evaluated in a future definitive trial

  4. Utilizing borehole electrical images to interpret lithofacies of fan-delta: A case study of Lower Triassic Baikouquan Formation in Mahu Depression, Junggar Basin, China

    Science.gov (United States)

    Yuan, Rui; Zhang, Changmin; Tang, Yong; Qu, Jianhua; Guo, Xudong; Sun, Yuqiu; Zhu, Rui; Zhou, Yuanquan (Nancy)

    2017-11-01

    Large-scale conglomerate fan-delta aprons were typical deposits on the slope of Mahu Depression during the Early Triassic. Without outcrops, it is difficult to study the lithofacies only by examining the limited cores from the main oil-bearing interval of the Baikouquan Formation. Borehole electrical imaging log provides abundant high-resolution geologic information that is obtainable only from real rocks previously. Referring to the lithology and sedimentary structure of cores, a case study of fan-deltas in the Lower Triassic Baikouquan Formation of the Mahu Depression presents a methodology for interpreting the complicated lithofacies utilizing borehole electrical images. Eleven types of lithologies and five types of sedimentary structures are summarized in borehole electrical images. The sediments are fining upward from gravel to silt and clay in the Baikouquan Formation. Fine-pebbles and granules are the main deposits in T1b1 and T1b2, but sandstones, siltstones and mudstones are more developed in T1b3. The main sedimentary textures are massive beddings, cross beddings and scour-and-fill structures. Parallel and horizontal beddings are more developed in T1b3 relatively. On integrated analysis of the lithology and sedimentary structure, eight lithofacies from electrical images, referred to as image lithofacies, is established for the fan-deltas. Granules to coarse-pebbles within massive beddings, granules to coarse-pebbles within cross and parallel beddings, siltstones within horizontal and massive beddings are the most developed lithofacies respectively in T1b1, T1b2 and T1b3. It indicates a gradual rise of the lake level of Mahu depression during the Early Triassic, with the fan-delta aprons retrograding towards to the margin of the basin. Therefore, the borehole electrical imaging log compensate for the limitation of cores of the Baikouquan Formation, providing an effective new approach to interpret the lithofacies of fan-delta.

  5. Towards a three-component model of fan loyalty: a case study of Chinese youth.

    Directory of Open Access Journals (Sweden)

    Xiao-xiao Zhang

    Full Text Available The term "fan loyalty" refers to the loyalty felt and expressed by a fan towards the object of his/her fanaticism in both everyday and academic discourses. However, much of the literature on fan loyalty has paid little attention to the topic from the perspective of youth pop culture. The present study explored the meaning of fan loyalty in the context of China. Data were collected by the method of in-depth interviews with 16 young Chinese people aged between 19 and 25 years who currently or once were pop fans. The results indicated that fan loyalty entails three components: involvement, satisfaction, and affiliation. These three components regulate the process of fan loyalty development, which can be divided into four stages: inception, upgrade, zenith, and decline. This model provides a conceptual explanation of why and how young Chinese fans are loyal to their favorite stars. The implications of the findings are discussed.

  6. Towards a three-component model of fan loyalty: a case study of Chinese youth.

    Science.gov (United States)

    Zhang, Xiao-xiao; Liu, Li; Zhao, Xian; Zheng, Jian; Yang, Meng; Zhang, Ji-qi

    2015-01-01

    The term "fan loyalty" refers to the loyalty felt and expressed by a fan towards the object of his/her fanaticism in both everyday and academic discourses. However, much of the literature on fan loyalty has paid little attention to the topic from the perspective of youth pop culture. The present study explored the meaning of fan loyalty in the context of China. Data were collected by the method of in-depth interviews with 16 young Chinese people aged between 19 and 25 years who currently or once were pop fans. The results indicated that fan loyalty entails three components: involvement, satisfaction, and affiliation. These three components regulate the process of fan loyalty development, which can be divided into four stages: inception, upgrade, zenith, and decline. This model provides a conceptual explanation of why and how young Chinese fans are loyal to their favorite stars. The implications of the findings are discussed.

  7. Towards a Three-Component Model of Fan Loyalty: A Case Study of Chinese Youth

    Science.gov (United States)

    Zhang, Xiao-xiao; Liu, Li; Zhao, Xian; Zheng, Jian; Yang, Meng; Zhang, Ji-qi

    2015-01-01

    The term “fan loyalty” refers to the loyalty felt and expressed by a fan towards the object of his/her fanaticism in both everyday and academic discourses. However, much of the literature on fan loyalty has paid little attention to the topic from the perspective of youth pop culture. The present study explored the meaning of fan loyalty in the context of China. Data were collected by the method of in-depth interviews with 16 young Chinese people aged between 19 and 25 years who currently or once were pop fans. The results indicated that fan loyalty entails three components: involvement, satisfaction, and affiliation. These three components regulate the process of fan loyalty development, which can be divided into four stages: inception, upgrade, zenith, and decline. This model provides a conceptual explanation of why and how young Chinese fans are loyal to their favorite stars. The implications of the findings are discussed. PMID:25886557

  8. Post-eruptive Submarine Terrace Development of Capelinhos, Azores

    Science.gov (United States)

    Zhongwei Zhao, Will; Mitchell, Neil; Quartau, Rui; Tempera, Fernando; Bricheno, Lucy

    2017-04-01

    Erosion of the coasts of volcanic islands by waves creates shallow banks, but how erosion proceeds with time to create them and how it relates to wave climate is unclear. In this study, historical and recent marine geophysical data collected around the Capelinhos promontory (western Faial Island, Azores) offer an unusual opportunity to characterize how a submarine terrace developed after the eruption. The promontory was formed in 1957/58 during a Surtseyan eruption that terminated with extensive lava forming new rocky coastal cliffs. Historical measurements of coastline position are supplemented here with coastlines measured from 2004 and 2014 Google Earth images in order to characterize coastline retreat rate and distance for lava- and tephra-dominated cliffs. Swath mapping sonars were used to characterize the submarine geometry of the resulting terrace (terrace edge position, gradient and morphology). Limited photographs are available from a SCUBA dive and drop-down camera deployments to ground truth the submarine geomorphology. The results reveal that coastal retreat rates have decreased rapidly with the time after the eruption, possibly explained by the evolving resistance to erosion of cliff base materials. Surprisingly, coastline retreat rate decreases with terrace width in a simple inverse power law with terrace width. We suspect this is only a fortuitous result as wave attenuation over the terrace will not obviously produce the variation, but nevertheless it shows how rapidly the retreat rate declines. Understanding the relationship between terrace widening shelf and coastal cliff retreat rate may be more widely interesting if they can be used to understand how islands evolve over time into abrasional banks and guyots.

  9. Maximizing the probability an aerial anti-submarine torpedo detects its target

    Science.gov (United States)

    Wang, Zhi-Jie

    2009-06-01

    As a result of the high speed of anti-submarine patrol aircraft as well as their wide range, high efficiency and other characteristics, aerial torpedoes released by anti-submarine patrol aircraft have become the key anti submarine tool. In order to improve operational efficiency, a deep study was made of the target detection probabilities for aerial torpedoes released by anti-submarine patrol aircraft. The operational modes of aerial torpedoes were analyzed and mathematical-simulation models were then established. The detection probabilities of three attacking modes were then calculated. Measures were developed for improving low probabilities of detection when attacking a probable target position. This study provides an important frame of reference for the operation of aerial torpedo released by anti-submarine patrol aircraft.

  10. Main devices design of submarine oil-water separation system

    Science.gov (United States)

    Cai, Wen-Bin; Liu, Bo-Hong

    2017-11-01

    In the process of offshore oil production, in order to thoroughly separate oil from produced fluid, solve the environment problem caused by oily sewage, and improve the economic benefit of offshore drilling, from the perspective of new oil-water separation, a set of submarine oil-water separation devices were designed through adsorption and desorption mechanism of the polymer materials for crude oil in this paper. The paper introduces the basic structure of gas-solid separation device, periodic separation device and adsorption device, and proves the rationality and feasibility of this device.

  11. Micro-tunneling as an alternative to submarine cable

    Energy Technology Data Exchange (ETDEWEB)

    Russo, D.A. [Seattle City Light, WA (United States); Hansen, D. [CH2M Hill, Bellevue, WA (United States)

    1994-12-31

    The geography that gives Seattle its beauty can pose unique challenges for the engineers attempting to provide service to the customers who live near or upon these features. Steep, wooded hills and greenbelts create familiar problems of construction and right-of-way maintenance. The waterways and adjoining shoreline zones present a more difficult set of requirements. When Seattle City Light determined it was necessary to install 2-26 KV feeders across the Salmon Bay waterway, they discovered that submarine cables could not be used. Shallow angle directional drilling and micro-tunneling were examined and it was fond that a microtunneled duct bank was the best method to use.

  12. Football Fan Aggression: The Importance of Low Basal Cortisol and a Fair Referee

    OpenAIRE

    Leander van der Meij; Fabian Klauke; Hannah L Moore; Yannick S Ludwig; Mercedes Almela; Van Lange, Paul A. M.

    2015-01-01

    Fan aggression in football (soccer) is a societal problem that affects many countries worldwide. However, to date, most studies use an epidemiological or survey approach to explain football fan aggression. This study used a controlled laboratory study to advance a model of predictors for fan aggression. To do so, football fans (n = 74) saw a match summary in which their favorite team lost against their most important rival. Next, we measured levels of aggression with the hot sauce paradigm, i...

  13. GIS-based cell model for simulating debris flow runout on a fan

    Science.gov (United States)

    Gregoretti, Carlo; Degetto, Massimo; Boreggio, Mauro

    2016-03-01

    A GIS-based cell model, based on a kinematic approach is proposed to simulate debris flow routing on a fan. The sediment-water mixture is modeled as a monophasic continuum, and the flow pattern is discretized by square cells, 1 m in size, that coincide with the DEM cells. Flow occurs from cells with a higher mixture free surface to those with a lower mixture free surface. A uniform-flow law is used if the elevation of the former cell is higher than that of the latter; otherwise, the flow is simulated using the broad-crested weir law. Erosion and deposition are simulated using an empirical law that is adjusted for a monophasic continuum. The sediment concentration in the routing volume is computed at each time step and controls both erosion and deposition. The cell model is used to simulate a debris flow that occurred on the Rio Lazer (Dolomites, North-Eastern Italian Alps) on November 4th, 1966. Furthermore, the hydrologic and the hydraulic conditions for the initiation of debris flow are simulated, providing the solid-liquid hydrograph of the resulting debris flow. A number of simulations has been carried out with physically reasonable parameters. The results are compared with the extension of the debris-flow deposition area and the map of observed depths of deposited sediments. This comparison shows that the proposed model provides good performance. The analysis of sensitivity carried out by systematically varying the model parameters shows that lower performances are associated with parameter values that are not physically reasonable. The same event is also simulated using a cellular automata model and a finite volume two-dimensional model. The results show that the two models provide a sediment deposition pattern less accurate than that provided by the present cell model.

  14. Geophysical evidence and inferred triggering factors of submarine landslides on the western continental margin of the Ulleung Basin, East Sea

    Science.gov (United States)

    Cukur, Deniz; Kim, Seong-Pil; Kong, Gee-Soo; Bahk, Jang-Jun; Horozal, Senay; Um, In-Kwon; Lee, Gwang-Soo; Chang, Tae-Soo; Ha, Hun-Jun; Völker, David; Kim, Jung-Ki

    2016-12-01

    Submarine landslides form very complex depositional and erosional features on the seafloor, and their dynamics and triggering processes are yet to be understood completely. Numerous studies are being undertaken both because of the scientific significance but also for their potential harm to seafloor infrastructure and coastal areas. This study investigates the styles and causes of landsliding along the western margin of the Ulleung Basin in the East Sea, based on multiple sparker, subbottom profiler, multibeam echosounder and sediment core datasets collected in 2015. The bathymetric analyses indicate that the southern slope of the Ulleung Basin has experienced at least seven submarine failures. These failures left clear arcuate-shaped scarps that initiated at water depths of 600 m. The observed headwall scarps have heights that exceed 60 m and appear to be the result of retrogressive-type failures. Seismic reflection data clearly image the basal sliding surface that is characterized by a prominent high-amplitude reflector. Chaotic-to-transparent seismic facies occur immediately downslope of the headwall scarps; these represent 20 m thick landslide deposits. Gravity cores taken from areas adjacent to the scars suggest that these slides are older than ca. 97 ka. Interpretation of the present data shows that faults appear to cut recent sediments upslope of scarps, and that the slope may still be in an active phase of failure. Seismic data also image various overpressurized gases and/or gas fluids, as evidenced by the occurrence of pockmarks and seismic chimneys in upslope or adjacent areas of the scarps. Hence, earthquakes associated with tectonic activity and development of fluid overpressure may have acted as the main conditioning factor for destabilizing the slope sediments. Geotechnical stability analyses indicate that the sampled slope sediments are exceptionally stable under present-day conditions, even under seismic loading. This finding points to additional

  15. Motivational factors affecting fan decisions to attend Premier Soccer ...

    African Journals Online (AJOL)

    Individuals' involvement in sport comes in different forms such as a profession, a hobby, or as entertainment. As part of the entertainment experience, an individual may be either a spectator or a fan. In South Africa, soccer is arguably the most popular sport, recreationally, economically as well as regarding active and ...

  16. Why do fans attend world Wrestling Entertainment? | Kruger | South ...

    African Journals Online (AJOL)

    This research examined the travel motives of South African World Wrestling Entertainment (WWE) fans at a live Smackdown event in July 2011, which was part of the WWE's world tour. Based on these motives, different market segments at the events were identified and profiled. This was the first time that the motives of ...

  17. The Alcyonacea (soft corals and sea fans) of Antsiranana Bay ...

    African Journals Online (AJOL)

    ... and 16 % of the reef benthos surveyed; 11 genera belonging to four families, and several unidentified gorgonians (sea fans) were recorded. Abundant and diverse Alcyonacea assemblages were recorded on reefs that were exposed with high water clarity. However, abundant and diverse communities were also observed ...

  18. K-pop Reception and Participatory Fan Culture in Austria

    National Research Council Canada - National Science Library

    Sang-Yeon Sung

    2014-01-01

    .... After South Korean pop singer Psy’s “Gangnam Style” music video topped the Austrian chart in October 2012, the number and size of K-pop events in Austria sharply increased, with fans organizing various participatory events, including K-pop auditions...

  19. K-pop Reception and Participatory Fan Culture in Austria

    National Research Council Canada - National Science Library

    Sang-Yeon Sung

    2013-01-01

    .... After South Korean pop singer Psy’s “Gangnam Style” music video topped the Austrian chart in October 2012, the number and size of K-pop events in Austria sharply increased, with fans organizing various participatory events, including K-pop auditions...

  20. Fans' multiple points of attachment and their influence on ...

    African Journals Online (AJOL)

    Rugby is one of South Africa's big three sports, alongside soccer and cricket. For many South African fans, rugby is a medium that provides entertainment, cultural identity and a sense of belonging to a particular sport. One of the main appeals for watching competitive sport events is the distinctive nature of competition.

  1. Are fan fiction and mythology really the same? [symposium

    Directory of Open Access Journals (Sweden)

    Tony Keen

    2016-03-01

    Full Text Available This short piece addresses some of the assumptions about the connections between Greek and Roman mythology and fan fiction that underlie this special issue of Transformative Works and Cultures, arguing that the connections are not always as simple as they are sometimes made out to be.

  2. The Nonrelativistic Scattering States of the Deng-Fan Potential

    Directory of Open Access Journals (Sweden)

    Bentol Hoda Yazarloo

    2013-01-01

    Full Text Available The approximately analytical scattering state solution of the Schrodinger equation is obtained for the Deng-Fan potential by using an approximation scheme to the centrifugal term. Energy eigenvalues, normalized wave functions, and scattering phase shifts are calculated. We consider and verify two special cases: the l=0 and the s-wave Hulthén potential.

  3. Identifying Crosscutting Concerns Using Fan-in Analysis

    NARCIS (Netherlands)

    Marin, M.; Van Deursen, A.; Moonen, L.

    2006-01-01

    Aspect mining is a reverse engineering process that aims at finding crosscutting concerns in existing systems. This paper proposes an aspect mining approach based on determining methods that are called from many different places, and hence have a high fan-in, which can be seen as a symptom of

  4. Design analysis, selection and application of fans for ventilation and ...

    African Journals Online (AJOL)

    ... fluid mechanics and head losses due to friction and across fittings were considered. Practical illustrations are provided for ducted and non-ducted ventilation and air conditioned distribution in buildings. The use of characteristic curves for selection of fans is also discussed. Journal of Applied Science and Technology Vol.

  5. Placing Fandom : Film Tourism in Contemporary Fan Culture

    NARCIS (Netherlands)

    A.S. Waysdorf (Abby)

    2017-01-01

    markdownabstractFilm tourism – visiting places associated with a film or television show – is an increasingly visible and popular practice. It is now almost expected whenever a new movie or television show draws on a particular place as a setting. But how are these places experienced by the fans who

  6. College Sports Fan Aggression: Implications for Residence Hall Discipline.

    Science.gov (United States)

    Coons, Christine Jansen; And Others

    1995-01-01

    Evaluated relationship between spectator aggression at football games and residence hall discipline. Results indicated that there is significant correlation, on five variables tested, between fan behavior and the increase of disciplinary cases during football weekends. Provides suggestions for interventions to reduce disciplinary actions. (JBJ)

  7. On passion and sports fans: a look at football.

    Science.gov (United States)

    Vallerand, Robert J; Ntoumanis, Nikos; Philippe, Frederick L; Lavigne, Geneviève L; Carbonneau, Noémie; Bonneville, Arielle; Lagacé-Labonté, Camille; Maliha, Gabrielle

    2008-10-01

    The purpose of the present research was to test the applicability of the Dualistic Model of Passion (Vallerand et al., 2003) to being a sport (football) fan. Three studies provided support for this dualistic conceptualization of passion. Study 1 showed that harmonious passion was positively associated with adaptive behaviours (e.g. celebrate the team's victory), whereas obsessive passion was positively associated with maladaptive behaviours (e.g. risking losing one's job to go to a game). Study 2 used a short Passion Scale and showed that harmonious passion was positively related to the positive affective life of fans during the 2006 FIFA World Cup, psychological health (self-esteem and life satisfaction), and public displays of adaptive behaviours (e.g. celebrate the team's victory into the streets), whereas obsessive passion was predictive of maladaptive affective life (e.g. hating opposing teams' fans) and behaviours (e.g. mocking opposing teams' fans). Finally, Study 3 examined the role of obsessive passion as a predictor of partner's conflict that in turn undermined partner's relationship satisfaction. Overall, the present results provided support for the Dualistic Model of Passion. The conceptual and applied implications of the findings are discussed.

  8. 30 CFR 75.310 - Installation of main mine fans.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Installation of main mine fans. 75.310 Section 75.310 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.310 Installation of main...

  9. Pump and Fan Technology Characterization and R&D Assessment

    Energy Technology Data Exchange (ETDEWEB)

    William Goetzler, Matt Guernsey, Greg Chung

    2015-10-01

    This report provides the Building Technologies Office (BTO) and the research and development (R&D) community with a technical and market analysis of pumps and fans as they pertain to commercial and residential buildings as well as key conclusions regarding the R&D opportunities that can help achieve BTO’s energy savings goals.

  10. Intermittent Flow Regimes in a Transonic Fan Airfoil Cascade

    Directory of Open Access Journals (Sweden)

    J. Lepicovsky

    2004-01-01

    velocity.To date, this flow behavior has only been observed in a linear transonic cascade. Further research is necessary to confirm this phenomenon occurs in actual transonic fans and is not the by-product of an endwall restricted linear cascade.

  11. Female fans of men's football - a case study in Denmark

    DEFF Research Database (Denmark)

    Pfister, Gertrud Ursula; Lenneis, Verena; Mintert, Svenja-Maria

    2013-01-01

    . The sources of information are reader and user data of mass media, results of surveys about the habits of the Danish population and the results of an interview study with female fans. A specific focus of this article is on the minority of female supporters who attend football games. How do they adapt...

  12. 78 FR 51749 - Proposed Information Collection; Ventilation Plan and Main Fan Maintenance Record (Pertains to...

    Science.gov (United States)

    2013-08-21

    ... collection for updating Ventilation Plan and Main Fan Maintenance Record 30 CFR 57.8520, and 57.8525. DATES...: Ventilation Plan and Main Fan Maintenance Record. OMB Number: 1219-0016. Affected Public: Business or other... Safety and Health Administration Proposed Information Collection; Ventilation Plan and Main Fan...

  13. Debris-flow dominance of alluvial fans masked by runoff reworking and weathering

    NARCIS (Netherlands)

    de Haas, Tjalling; Ventra, Dario; Carbonneau, Patrice E.; Kleinhans, Maarten G.

    2014-01-01

    Arid alluvial fan aggradation is highly episodic and fans often comprise active and inactive sectors. Hence the morphology and texture of fan surfaces are partly determined by secondary processes of weathering and erosion in addition to primary processes of aggradation. This introduces considerable

  14. Fans' Judgments about the 1994-95 Major League Baseball Players' Strike.

    Science.gov (United States)

    Mellor, Steven; Paley, Michael J.; Holzworth, R. James

    1999-01-01

    Used a multilevel analysis of surveys completed by 119 baseball fans to examine how strike tactics influenced fan support of the 1994-1995 Major League Baseball players' strike. Discusses factors that influenced fan opinion and the use of hierarchical linear modeling. (SLD)

  15. Football fan aggression: The importance of low basal cortisol and a fair referee

    NARCIS (Netherlands)

    van der Meij, L.; Klauke, F; Moore, H.L.; Ludwig, Y.S.; Almela, M.; van Lange, P.A.M.

    2015-01-01

    Fan aggression in football (soccer) is a societal problem that affects many countries worldwide. However, to date, most studies use an epidemiological or survey approach to explain football fan aggression. This study used a controlled laboratory study to advance a model of predictors for fan

  16. Interaction between Dutch soccer teams and fans: a mathematical analysis through cooperative game theory

    NARCIS (Netherlands)

    Hou, D.; Driessen, Theo

    2012-01-01

    Inspired by the first lustrum of the Club Positioning Matrix (CPM) for professional Dutch soccer teams, we model the interaction between soccer teams and their potential fans as a cooperative cost game based on the annual voluntary sponsorships of fans in order to validate their fan registration in

  17. "We're Gators...Not Just Gator Fans": Serious Leisure and University of Florida Football.

    Science.gov (United States)

    Gibson, Heather; Willming, Cynthia; Holdnak, Andrew

    2002-01-01

    Interviewed University of Florida Gator football fans to examine meanings, rituals, and practices associated with being a fan. Emergent themes confirmed Stebbins' (1979; 1992) six characteristics of serious leisure (e.g., perseverance, unique ethos, and identification). Results suggest that being a Gator football fan provides both a source of…

  18. Surface morphology of fans in the high-Arctic periglacial environment of Svalbard : Controls and processes

    NARCIS (Netherlands)

    De Haas, Tjalling; Kleinhans, Maarten G.; Carbonneau, Patrice E.; Rubensdotter, Lena; Hauber, Ernst

    2015-01-01

    Fan-shaped landforms occur in all climatic regions on Earth. They have been extensively studied in many of these regions, but there are few studies on fans in periglacial, Arctic and Antarctic regions. Fans in such regions are exposed to many site-specific environmental conditions in addition to

  19. Radionuclides as tracer for submarine groundwater discharge (SGD) research at Dapeng Bay in Southern Taiwan

    Science.gov (United States)

    Huang, Jun-Chen; Su, Chih-Chieh

    2017-04-01

    Conventionally, river is the most important source for delivering nutrients, such as nitrogen, phosphorus and silicon, and trace elements into the ocean. The issues of land-sea interaction by rivers have been long-tern concerned and studied, on contrary, the pathway and impact through submarine groundwater discharge (SGD) is still unclear and the relevant researches need to be strengthened. The research site, Dapeng Bay, is located at Pingtung County in Southern Taiwan. Dapeng Bay is an bag-shape lagoon with a sand spit serving as the single outlet of the bay. The longshore currents transport sediments which delivered by Donggang and Linbian Rivers deposited at the nearshore and eventually form the semi-enclosed shallow bay. In the Dapeng Bay, there is no river poured into the lagoon and the main sources of freshwater are rainwater, domestic wastewater and fish ponds etc. The tidal driven water exchange between lagoon and ocean is through the sand spit outlet. The purpose of this study is to evaluate the weighting and seasonal change between SGD and riverine input in the Dapeng Bay. The radium isotopes, 223Ra (11.4d), 224Ra (3.7d), 226Ra (1600y), 228Ra (5.7y), were used as tracers for assessing SGD and riverine inputs. Samples were collected by using MnO2-coated fibers for radium isotopes adsorption.

  20. Submarine landslides of San Pedro Escarpment, southwest of Long Beach, California

    Science.gov (United States)

    Bohannon, R.G.; Gardner, J.V.

    2004-01-01

    The coastal infrastructure of the southern greater Los Angeles metropolitan area would be profoundly affected by a large tsunami. Submarine slope failures and active faults, either of which could have generated a tsunami, are known on the shelf and slope near Long Beach. Large slope failures are present on the San Pedro Escarpment and on the basin slope adjacent to the San Pedro shelf. The southeastern part of the escarpment has had a long history of slope failure. The most recent failure, the Palos Verdes slide, is over 4.5 km long, has been dated as 7500 years old, and involved over 0.34 km 3 of material, which now litters the adjacent basin floor. Other, smaller, deposits from nearby failures are also present, as are buried wedges of debris that indicate slope failures have occurred locally throughout the Holocene and much of the late Pleistocene. Slope failures have occurred in response to continual Quaternary uplift of the Palos Verdes anticlinorium. The Palos Verdes slide could potentially have generated a failure-related tsunami with an amplitude in the range of 8-12 m because it apparently failed catastrophically, started in shallow water, evolved on low-drag bedding planes, had a long slide path, and involved high-strength lithified material. ?? 2003 Elsevier B.V. All rights reserved.

  1. On the geotechnical characterisation of the polluted submarine sediments from Taranto.

    Science.gov (United States)

    Vitone, Claudia; Federico, Antonio; Puzrin, Alexander M; Ploetze, Michael; Carrassi, Elettra; Todaro, Francesco

    2016-07-01

    This paper reports the results of the first geomechanical laboratory experiments carried out on the polluted submarine clayey sediments of the Mar Piccolo in Taranto (South of Italy). The study had to face with extreme difficulties for the very soft consistency of the sediments and the contaminants. The mineralogy, composition and physical properties of the sediments were analysed, along with their compression and shearing behaviour. The investigation involved sediments up to about 20 m below the seafloor, along three vertical profiles in the most polluted area of the Mar Piccolo, facing the Italian Navy Arsenal. The experimental results were used to derive a preliminary geotechnical model of the site, necessary for the selection and design of the most sustainable in situ mitigation solutions. Moreover, the experimental data reveal that the clayey sediments of the most polluted top layer do not follow the classical geotechnical correlations for normally consolidated deposits. This seems to open interesting perspectives about the effects of pollutants on the geotechnical behaviour of the investigated sediments.

  2. Worst case meteorological scenario for Norway in case of hypothetical accident related to recovery of the Russian submarine K-27

    Energy Technology Data Exchange (ETDEWEB)

    Bartnicki, J.; Klein, H. [Norwegian Meteorological Institute, Oslo (Norway); Centre for Environmental Radioactivity, Aas (Norway); Amundsen, I.; Hosseini, A. [Norwegian Radiation Protection Authority, Oesteraas (Norway); Centre for Environmental Radioactivity, Aas (Norway); Haakenstad, H. [Norwegian Meteorological Institute, Oslo (Norway); Lind, O.C.; Salbu, B. [Norwegian University of Life Sciences, Aas (Norway); Centre for Environmental Radioactivity, Aas (Norway)

    2014-07-01

    This study is a part of a comprehensive Norwegian project led by Norwegian Radiation Protection Authority assessing risks related to a potential salvaging and decommissioning of the Russian nuclear submarine, K-27. In September 1981, the K-27 submarine was scuttled at shallow waters in the outer part of Stepovogo Bay, situated at the north-eastern coast of Novaya Zemlya. One of the scenarios that are included in the assessment is the lifting of the submarine to the surface and the subsequent transport to the Murmansk area for decommissioning. Thus, the risk of a criticality accident as a consequence of lifting and transport event cannot be ignored. A hypothetical accident might pose a serious threat to Norwegian territories and has to be considered from different perspectives. Here, we focus on the worst case meteorological scenario for Norway, but the same approach can be applied for other Scandinavian countries and Russia. As a first step, a large database with meteorological data has been prepared for the period of thirty years (1980-2010). These meteorological data are available in the 1000 km x 1000 km domain which includes both the entire Norwegian territory and the region of Novaya Zemlya. The spatial resolution of the meteorological data is 11 km and temporal 3 hours. The vertical structure includes 40 layers. The most important meteorological elements are the 3-D velocity field, the surface precipitation field and the 3-D temperature field. The second step is the development of the source terms for potential accidents which can be used by the dispersion model SNAP (Severe Nuclear Accident Program). Three locations for potential accidents with subsequent releases of radioactivity to the environment are assumed: 1) at the present location of K-27, 2) transport on the route to Murmansk and 3) in the Murmansk region. In the third step, the SNAP model will be run with meteorological data starting every 6. hour of each day during the 30 years period. As a result

  3. Life Sciences Laboratory 2 Fan Exhaust Mixing Study

    Energy Technology Data Exchange (ETDEWEB)

    Flaherty, Julia E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Antonio, Ernest J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-28

    An SF6 tracer release was performed in the LSL-II ventilation stack over the weekend of March 5, 2016. The primary purpose of this study was to experimentally determine the gaseous concentration of material from a fume hood to the fan outlet, as well as at typical worker locations, to gain an understanding of potential worker exposures impacts. Five different fan operating configurations were utilized to ensure that the full spectrum of historical operating configurations was addressed. Some summary points from this study include: •Relatively high concentrations were observed within the stack area. –Between 50 and 100% of the exhaust concentration may be observed within the stack. •Background concentrations were observed outside the stack area. –Workers outside the stack itself, but on the roof, are unlikely to be impacted by the exhaust. •Elevated concentrations on the order of 25% of the exhaust concentrations were observed within the Penthouse. •Transport time from a laboratory fume hood to the exhaust fan is within one to two minutes. •Penthouse concentrations climb from background levels to steady state over 15+ minutes. •Wind speed and wind direction did not play a significant role in the test outcomes. –A slight bias in the concentration distribution may be discernable based on wind speed and direction. •When both fans are operating, material from fume hoods on the east side preferentially flow through the east fan, while material from fume hoods on the west side preferentially flow through the west fan. This effectively doubles the concentration at that fan. This mixing study will inform other study components to develop a more complete picture of the worker potential exposure from LSL-II Rooftop activities. Estimating the mean concentration in the stack from chemical inventories and fume hood emissions for both current and historical laboratory activities is a separate effort. These estimates of mean ventilation

  4. Experimental Evaluation of Installed Cooking Exhaust Fan Performance

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Brett C.; Delp, William W.; Apte, Michael G.

    2010-11-01

    The installed performance of cooking exhaust fans was evaluated through residential field experiments conducted on a sample of 15 devices varying in design and other characteristics. The sample included two rear downdraft systems, two under-cabinet microwave over range (MOR) units, three different installations of an under-cabinet model with grease screens across the bottom and no capture hood, two devices with grease screens covering the bottom of a large capture hood (one under-cabinet, one wall-mount chimney), four under-cabinet open hoods, and two open hoods with chimney mounts over islands. Performance assessment included measurement of airflow and sound levels across fan settings and experiments to quantify the contemporaneous capture efficiency for the exhaust generated by natural gas cooking burners.Capture efficiency is defined as the fraction of generated pollutants that are removed through the exhaust and thus not available for inhalation of household occupants. Capture efficiency (CE) was assessed for various configurations of burner use (e.g., single front, single back, combination of one front and one back, oven) and fan speed setting. Measured airflow rates were substantially lower than the levels noted in product literature for many of the units. This shortfall was observed for several units costing in excess of $1000. Capture efficiency varied widely (from<5percent to roughly 100percent) across devices and across conditions for some devices. As expected, higher capture efficiencies were achieved with higher fan settings and the associated higher air flow rates. In most cases, capture efficiencies were substantially higher for rear burners than for front burners. The best and most consistent performance was observed for open hoods that covered all cooktop burners and operated at higher airflow rates. The lowest capture efficiencies were measured when a front burner was used with a rear backdraft system or with lowest fan setting for above the range

  5. Seismicity and sedimentation rate effects on submarine slope stability

    Science.gov (United States)

    Ten Brink, U. S.; Andrews, B. D.; Miller, N. C.

    2016-12-01

    Large submarine mass-transport scars are commonly observed on continental margins, but are noticeably less abundant on margins that experience frequent earthquakes than on those that seldom experience them. This is a surprising observation, given that horizontal acceleration from earthquakes and associated strength loss from cyclic loading and liquefaction are commonly thought to provide the primary triggers for inducing failures and subsequent mass movements. Mapping submarine failure scars in ten margins worldwide, we find decreasing scar abundance with both increasing frequency of earthquakes and decreasing sedimentation rate. The decrease in scar abundance is interpreted to represent increasing slope stability. The increase in stability is non linear (power law with btectonic activity (salt diapirs, seamount subduction, etc.) leads to relatively rapid oversteepening of the slope, implying that the morphology of most margins is in fact, stable over many earthquake cycles. Note that the above correlation averages scar area and sedimentation rate over entire margin areas. Variations in sedimentation rate with time, such as over glacial-interglacial cycles, and intra-margin variations in seismic attenuation, sedimentation rate, composition, and pore pressure, have likely affected the abundance of slope failures in time and space.

  6. An Automatic Procedure for the Quantitative Characterization of Submarine Bedforms

    Directory of Open Access Journals (Sweden)

    Massimo Di Stefano

    2018-01-01

    Full Text Available A model for the extraction and quantitative characterization of submarine landforms from high-resolution digital bathymetry is presented. The procedure is fully automated and comprises two parts. The first part consists of an analytical model which extracts quantitative information from a Digital Elevation Model in the form of objects with similar parametric characteristics (terrain objects. The second part is a rule-based model where the terrain objects are reclassified into distinct landforms with well-defined three dimensional characteristics. For the focus of this work, the quantitative characterization of isolated dunes (height greater than 2 m is used to exemplify the process. The primary metrics used to extract terrain objects are the flatness threshold and the search radius, which are then used by the analytical model to identify the feature type. Once identified as dunes, a sequence of spatial analysis routines is applied to identify and compute metrics for each dune including length, height, width, ray of curvature, slope analysis for each stoss and lee side, and dune symmetry. Dividing the model into two parts, one scale-dependent and another centered around the shape of the landform, makes the model applicable to other submarine landforms like ripples, mega-ripples, and coral reefs, which also have well-defined three-dimensional characteristics.

  7. Fin propulsion on a human-powered submarine

    Science.gov (United States)

    Anderson, Iain A.; Pocock, Benjamin; Harbuz, Antoni; Algie, Cam; Vochezer, Daniel; Chao, Ryan; Lu, Benjamin

    2015-03-01

    Nearly all surface and underwater vessels are driven by screw propulsion; ideal for coupling to rotary engines and well understood after over a century of development. But most aquatic creatures use fins for swimming. Although there are sound evolutionary reasons why fish have fins and not propellers, they are nevertheless agile, fast and efficient. Although fish-like robots such as the MIT Robotuna are providing good insight into fin-based swimming there are advantages for using humans in the experimental device. Like an airplane test pilot they can write crash reports. We present preliminary observations for the human powered finned submarine: Taniwha. The sub participated in the 2nd European International Submarine races in Gosport UK where it received a trophy for "Best Non-Propeller Performance". Two sets of Hobie Mirage fin drives fixed to the upper and lower rear surfaces of the sub are pedaled by the pilot. The pilot also has two levers at the front, one to pitch a pair of dive planes and one for yawing a large rudder. Good speed, we estimate to be greater than 6 m/s is possible with these fins although we haven't explored their full potential. Straying too near the surface or bottom can lead to an instability, synonymous to a stall, such that control is lost. The mechanism for this will be discussed and solutions offered. Fish are 400 million years in front of us but one day we'll catch them.

  8. Are tilt measurements useful in detecting tsunamigenic submarine landslides?

    Science.gov (United States)

    Brune, Sascha; Babeyko, Andrey Y.; Sobolev, Stephan V.

    2009-06-01

    Large submarine landslides can generate dangerous tsunamis. Because of their long-period signal, detection of landslides by common seismological methods is difficult. Here we suggest a method of detecting submarine landslides by using an array of land-based tiltmeters. The displacement of a large volume of sediments during landsliding produces a detectable elastic response of the lithosphere. We propose a technique to calculate this response and to invert for tsunami relevant parameters like slide location, volume, and velocity. We exemplify our method by applying it to the Storegga slide west of Norway and other tsunamigenic landslide events. The parameter which can be most robustly estimated from tiltmeter array measurements is the product of slide volume and its velocity (slide tsunamigenic potential). This parameter also controls the amplitude of the generated tsunami wave. The inversion accuracy of this parameter and the estimated tsunami height near the coast depends on the noise level of tiltmeter measurements, distance of the tiltmeters from the slide, and slide tsunamigenic potential itself. The tsunamigenic potential of the most dangerous slides like Storegga can be estimated well by tiltmeters at the coast if the effective noise level does not exceed 50 nrad.

  9. Feasibility study of submarine diesel exhaust valve interspace coating application

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, W.; Zhou, M.; Bibby, D.; Huang, J.

    2008-05-15

    This document described a feasibility study conducted to evaluate surface coating systems applied to the surface of a diesel exhaust valve interspace on a VICTORIA Class submarine. A series of laboratory studies were conducted to determine the physical characteristics of the coatings, which will be subjected to high service temperatures, diesel exhaust gas, and seawater. The valves were made of Q1N steel castings. The surface coatings were designed to provide corrosion resistance and thermal protection to the valves. As part of the study, a survey was conducted on various state-of-the-art surface coating systems. Coatings were rated on their ability to protect the Q10 steel surface from corrosion, high temperatures and seawater. An additional requirement was that the coatings should not produce high amounts of hydrogen. Plating trials were conducted with a nickel-based alloy (Ni-Cu-P) placed on Q1N steel substrates with a hypophosphite reducing agent. The results of X-ray diffraction (XRD) analyses suggested that the coatings can also be used to protect the external surfaces of various submarine components. 54 refs., 4 tabs., 10 figs.

  10. Cyclic eruptions and sector collapses at Monowai submarine volcano, Kermadec arc: 1998-2007

    Science.gov (United States)

    Chadwick, W. W.; Wright, I. C.; Schwarz-Schampera, U.; Hyvernaud, O.; Reymond, D.; de Ronde, C. E. J.

    2008-10-01

    Repeated multibeam bathymetric surveys at Monowai Cone, a shallow submarine basaltic volcano and part of the Monowai Volcanic Center in the northern Kermadec arc, were conducted in 1998, 2004, and 2007. These surveys document dramatic depth changes at the volcano including negative changes up to -176 m from two sector collapses and positive changes up to +138 m from volcanic reconstruction near the summit and debris avalanche deposits downslope of the slide scars. One sector collapse occurred on the SE slope between 1998 and 2004 with a volume of ˜0.09 km3, and another occurred on the SW slope between 2004 and 2007 with a volume of ˜0.04 km3. The volume of positive depth change due to addition of volcanic material by eruption is of the same order: ˜0.05 km3 between 1998 and 2004 and ˜0.06 km3 between 2004 and 2007. During these time intervals, monitoring by the Polynesian Seismic Network detected frequent T wave swarms at Monowai, indicative of explosive eruptive activity every few months. An unusual T wave swarm on 24 May 2002 was previously interpreted as the collapse event between the 1998 and 2004 surveys, but no similarly anomalous T waves were detected between 2004 and 2007, probably because the Polynesian Seismic Network stations were acoustically shadowed from the second slide event. We interpret that the sector collapses on Monowai are caused by the unstable loading of fragmental erupted material on the summit and steep upper slopes of the volcano (>20°). Moreover, there appears to be a cyclic pattern in which recurrent eruptions oversteepen the cone and periodically lead to collapse events that transport volcaniclastic material downslope to the lower apron of the volcano. Volumetric rate calculations suggest that these two processes may be more or less in equilibrium. The repeated collapses at Monowai are relatively modest in volume (involving only 0.1-0.5% of the edifice volume), have occurred much more frequently than is estimated for larger debris

  11. Tectonic controls on nearshore sediment accumulation and submarine canyon morphology offshore La Jolla, Southern California

    Science.gov (United States)

    Le Dantec, Nicolas; Hogarth, Leah J.; Driscoll, Neal W.; Babcock, Jeffrey M.; Barnhardt, Walter A.; Schwab, William C.

    2010-01-01

    CHIRP seismic and swath bathymetry data acquired offshore La Jolla, California provide an unprecedented three-dimensional view of the La Jolla and Scripps submarine canyons. Shore-parallel patterns of tectonic deformation appear to control nearshore sediment thickness and distribution around the canyons. These shore-parallel patterns allow the impact of local tectonic deformation to be separated from the influence of eustatic sea-level fluctuations. Based on stratal geometry and acoustic character, we identify a prominent angular unconformity inferred to be the transgressive surface and three sedimentary sequences: an acoustically laminated estuarine unit deposited during early transgression, an infilling or “healing-phase” unit formed during the transgression, and an upper transparent unit. Beneath the transgressive surface, steeply dipping reflectors with several dip reversals record faulting and folding along the La Jolla margin. Scripps Canyon is located at the crest of an antiform, where the rocks are fractured and more susceptible to erosion. La Jolla Canyon is located along the northern strand of the Rose Canyon Fault Zone, which separates Cretaceous lithified rocks to the south from poorly cemented Eocene sands and gravels to the north. Isopach and structure contour maps of the three sedimentary units reveal how their thicknesses and spatial distributions relate to regional tectonic deformation. For example, the estuarine unit is predominantly deposited along the edges of the canyons in paleotopographic lows that may have been inlets along barrier beaches during the Holocene sea-level rise. The distribution of the infilling unit is controlled by pre-existing relief that records tectonic deformation and erosional processes. The thickness and distribution of the upper transparent unit are controlled by long-wavelength, tectonically induced relief on the transgressive surface and hydrodynamics.

  12. Gas Turbine Engine Having Fan Rotor Driven by Turbine Exhaust and with a Bypass

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2016-01-01

    A gas turbine engine has a core engine incorporating a core engine turbine. A fan rotor is driven by a fan rotor turbine. The fan rotor turbine is in the path of gases downstream from the core engine turbine. A bypass door is moveable from a closed position at which the gases from the core engine turbine pass over the fan rotor turbine, and moveable to a bypass position at which the gases are directed away from the fan rotor turbine. An aircraft is also disclosed.

  13. Fans and their applications in General Topology, Functional Analysis and Topological Algebra

    OpenAIRE

    Banakh, Taras

    2016-01-01

    A family of closed subsets of a topological space $X$ is called a (strict) $Cld$-fan in $X$ if this family is (strictly) compact-finite but not locally finite in $X$. Applications of (strict) $Cld$-fans are based on a simple observation that $k$-spaces contain no $Cld$-fan and Ascoli spaces contain no strict $Cld$-fan. In this paper we develop the machinery of (strict) fans and apply it to detecting the $k$-space and Ascoli properties in spaces that naturally appear in General Topology, Funct...

  14. Numerical investigation of geometric parameter effects on the aerodynamic performance of a Bladeless fan

    OpenAIRE

    Jafari, Mohammad; Afshin, Hossein; Farhanieh, Bijan; Sojoudi, Atta

    2016-01-01

    Aerodynamic performance of a Bladeless fan is numerically investigated considering the effect of five geometric parameters. Airflow through this fan was analyzed by simulating a Bladeless fan within a 2 m × 2 m × 4 m room. Analysis of the flow field inside the fan and the evaluation of its performance were obtained by solving conservations of mass and momentum equations for the aerodynamic investigations. In order to design the Bladeless fan an Eppler 473 airfoil profile was used as the cross...

  15. Comparison of Subaerial and Submarine Mixing and Sediment Transport in Sinuous Channel Bends Using Turbulence-Resolving Numerical Models

    Science.gov (United States)

    Schmeeckle, M. W.

    2014-12-01

    Large eddy simulations (LES) of turbulence and sediment suspension are conducted in both subaerial and submarine meandering channels. The Boussinesq approximation of buoyancy is applied to the spatially-filtered, Navier-Stokes equations through the simultaneous solution of the suspended sediment continuity equation with the Smith-McLean boundary condition. Production of turbulence and, consequently, turbulent kinetic energy is stronger at channel bends than in straight sections. This pattern is more pronounced in subaerial channels. Depth integrated, two-dimensional models of turbidity currents critically rely upon parameterization of the entrainment of water at the top of the flow and sediment exchange with the bed. Secondary flow and turbulence structure due to channel sinuosity significantly alter these parameterizations and the assumed vertical profiles of velocity and sediment concentration. Large turbulent structures episodically inject relatively clear water from the top to the base of the flow at the outside of channel bends, and, simultaneously, sediment laden fluid is ejected from the bed at the inside of channel bends. As a result, sediment deposition in sinuous channels is reduced compared to application of two-dimensional models. The LES turbidity current model is extended to channel morphodynamics by grid adjustment at each fluid and sedment time step. The LES morphodynamic model has been tested, thus far, in strongly depositional sinuous channel turbidity currents. Relatively uniform channel deposition and rapidly developing sharp-crested levees are built in these conditions. Further simulations involving partially erosional conditions and bedload transport will be presented.

  16. Occupational stress in submariners: the impact of isolated and confined work on psychological well-being.

    Science.gov (United States)

    Brasher, Kate S; Dew, Angela B C; Kilminster, Shaun G; Bridger, Robert S

    2010-03-01

    This study aimed to identify work-related and personal factors associated with occupational stress in submariners. Work and well-being questionnaires were distributed to 219 male submariners (mean age 34 years), as part of a larger cohort study involving a stratified sample of 4951 Royal Navy (RN) personnel. The stress rate in submariners was 40%; significantly higher than the stress rate in the general RN, although once demographic factors were controlled for in a matched control sample, this difference was no longer significant. A summary model accounted for 49% of the variance in submariner stress, with key differences emerging between the occupational factors associated with stress in submariners and in the general RN. The longitudinal nature of this study permits stress in submariners to be monitored over 5 years, which will provide valuable insights into the chronicity of stress in this specialised occupational group. STATEMENT OF RELEVANCE: This paper contributes to the current literature on the negative impact of working in isolated conditions. It is demonstrated that occupational stress in submarines can be partially explained using current theories of stress in the workplace. However, the constraints of a restricted environment introduce additional factors which can also be associated with occupational stress.

  17. Measuring currents in submarine canyons: technological and scientific progress in the past 30 years

    Science.gov (United States)

    Xu, J. P.

    2011-01-01

    The development and application of acoustic and optical technologies and of accurate positioning systems in the past 30 years have opened new frontiers in the submarine canyon research communities. This paper reviews several key advancements in both technology and science in the field of currents in submarine canyons since the1979 publication of Currents in Submarine Canyons and Other Sea Valleys by Francis Shepard and colleagues. Precise placements of high-resolution, high-frequency instruments have not only allowed researchers to collect new data that are essential for advancing and generalizing theories governing the canyon currents, but have also revealed new natural phenomena that challenge the understandings of the theorists and experimenters in their predictions of submarine canyon flow fields. Baroclinic motions at tidal frequencies, found to be intensified both up canyon and toward the canyon floor, dominate the flow field and control the sediment transport processes in submarine canyons. Turbidity currents are found to frequently occur in active submarine canyons such as Monterey Canyon. These turbidity currents have maximum speeds of nearly 200 cm/s, much smaller than the speeds of turbidity currents in geological time, but still very destructive. In addition to traditional Eulerian measurements, Lagrangian flow data are essential in quantifying water and sediment transport in submarine canyons. A concerted experiment with multiple monitoring stations along the canyon axis and on nearby shelves is required to characterize the storm-trigger mechanism for turbidity currents.

  18. Evaluation of tsunami hazard associated to the Assi submarine landslide along the Ionian Calabrian margin, Italy

    Science.gov (United States)

    Zaniboni, F.; Tinti, S.; Pagnoni, G.; Ceramicola, S.; Planinsek, P.; Marson, I.

    2012-04-01

    Continental margins are frequently prone to submarine sliding, which constitutes a severe hazard when the slides occur close to the coast and move in shallow water, since they might generate destructive waves. In the Mediterranean Sea, especially, the potential sources of landslide-induced tsunamis are often located critically close to coastal communities, and the knowledge of how the event may evolve together with awareness of the associated risk are key factors for civil protection issues. A series of recent geophysical surveys carried out by OGS in the framework of The MAGIC (Marine Geohazards along the Italian Coasts) project, brought relevant contribution to the imaging and functioning of submarine landslides. Along the tectonically active Ionian Calabrian Margin (ICM) a multiple failure event has been identified (Assi landslide) at about 6 km away from the coastline nearby Riace Marina: headwall scars, mobilized sediments along the scour, stacked deposits at and near the seabed, at the foot of the slope have been identified. The data allowed to estimate the volume of mobilized material and to reconstruct the failure dynamics. One of the most susceptible areas along the ICM is located in the southern part, around the coastal village of Riace Marina in the province of Reggio Calabria. The coastal area adjacent to Riace Marina is not a very urbanized settlement, however becomes intensely crowded in the tourist season. The evidence of the occurrence of such an extensive failure event so close to the coast, motivated us to assess the potential tsunamigenic hazard associated to the Assi submarine landslide event in this area. A number of scenarios were considered starting from a more conservative scenario (i.e. a sequence of successive failures) to the most critical case (i.e. a unique big event mobilizing all the sediments at once). In this work we present the results concerning the worst-case scenario, that is we assume that a single big landslide event occurred

  19. Tsunami run-up and inundation along the coast of Sabah and Sarawak, Malaysia due to a potential Brunei submarine mass failure.

    Science.gov (United States)

    Tan, Wai Kiat; Teh, Su Yean; Koh, Hock Lye

    2017-07-01

    Submarine landslides, also known as submarine mass failures (SMFs), are major natural marine disasters that could critically damage coastal facilities such as nuclear power plants and oil and gas platforms. It is therefore essential to investigate submarine landslides for potential tsunami hazard assessment. Three-dimensional seismic data from offshore Brunei have revealed a giant seabed mass deposited by a previous SMF. The submarine mass extends over 120 km from the continental slope of the Baram Canyon at 200 m water depth to the deep basin floor of the Northwest Borneo Trough. A suite of in-house two-dimensional depth-averaged tsunami simulation model TUNA (Tsunami-tracking Utilities and Application) is developed to assess the vulnerability of coastal communities in Sabah and Sarawak subject to potential SMF tsunami. The submarine slide is modeled as a rigid body moving along a planar slope with the center of mass motion parallel to the planar slope and subject to external forces due to added mass, gravity, and dissipation. The nonlinear shallow water equations are utilized to simulate tsunami propagation from deepwater up to the shallow offshore areas. A wetting-drying algorithm is used when a tsunami wave reaches the shoreline to compute run up of tsunami along the shoreline. Run-up wave height and inundation maps are provided for seven densely populated locations in Sabah and Sarawak to highlight potential risks at each location, subject to two scenarios of slide slopes: 2° and 4°. The first wave may arrive at Kudat as early as 0.4 h after the SMF, giving local communities little time to evacuate. Over a small area, maximum inundated depths reaching 20.3 m at Kudat, 26.1 m at Kota Kinabalu, and 15.5 m at Miri are projected, while the maximum inundation distance of 4.86 km is expected at Miri due to its low-lying coast. In view of the vulnerability of some locations to the SMF tsunami, it is important to develop and implement community resilience

  20. Representation of American versus non-American fans in Baillie Walsh's Springsteen & I

    Directory of Open Access Journals (Sweden)

    Maryn Claire Wilkinson

    2015-06-01

    Full Text Available This article explores the representation of American versus non-American fans in Baillie Walsh's 2013 crowd/fan-sourced documentary Springsteen & I. The film—as much as it was fed by a wide and international range of fan-produced material—ultimately produced and presented one particular type of fan as privileged and appropriate to speak for all: the American Springsteen fan. The film does so in three main ways: by presenting American fans as more authentically connected to Springsteen's language and lyrics (they truly "understand" his work; by showing that American fans relate to Springsteen's world and themes in more authentic ways; and by presenting American fans as experiencing a better, closer, more authentic Springsteen when seeing him perform live. The essay thus reexamines fan stereotyping from the perspective of national identity. It aims to rearticulate the necessity of the vigilance and scrutiny of crowd-sourced fan texts because they have profound effects on how fans are taught to view themselves in and by the media.